(ii)
EDUCATION AND TRAINING EQUIPMENT
Declaration of Conformity:
Directives
I
(where applicable)
89/392JCEE as amended by 91/368/EEC
89/336/CEE
72/23/CEE
We declare that the following unit complies with the above EEC directives:
A660 Air Conditioning Laboratory Unit
The use of the apparatus outside the classroom, laboratory, study area or similar
such place invalidates confonnity with the protection requirements of the
Electromagnetic Compatibility Directive (89/336/EEC) and could lead to local.
prosecution.
For and on behalf of
P.A. niL TON LIMITED
Technical Director
n
Ii~
I
P .A. HILTON
LIMITED
Horsebridge Mill, King's Sombome,
Stockbridge. Hampshire. SO20 6PX.
England.
Tel No. National Romsev (01794) 388382
International
+44 1794 388382
Fax No. +44 1794 388129
E-mail:
sal~s@p-a-hilton.co.uk
(iii)
INDEx.
~
SYMBOLS AND UNITS
2
SUFFDCES and/or STATES
3
SCHEMA TIC DIAGRAM
4
CONTROL PANEL DIAGRAM
6
INTRODUCTION
7
Air Conditioning
7
Air Conditioning Plant
7
Hygrometers
8
Comfort Conditions
8
Human Comfort
OPTIONAL UPGRADES
Order of Installation
INST ALLA TION AND COMMISSIONING
Accessories
Installation
Description
Specification
Services Required
Useful Data
Operation
Shutting Down After Use
Icing at Evaporator
High PressureCut-Out
High TemperatureCut-Out (In Duct)
High TemperatureCut-Out (Steam Generator)
RECOMENDED TEST CONDITIONS
Humidification
De-humjdification
Unit Capabilities
Energy Transfers
MAINTENANCE
Earth LeakageTesting
Refrigeration Circuit
Leak Detection
8
10
II
12
12
13
24
2S
26
27
28
29
29
29
29
29
30
30
30
30
30
32
32
32
32
~
(iv)
~
n,~~!
~1
t
I
m
I
Re-charging
32
Cleaning
33
SuperheatControl
33
Manometers
33
Care of Boiler
33
Wet Bulb Sensors
33
Testing the RCCB
34
DETERMINATION
OF HEAT LOSS FROM BOILER
THEORY
36
Composition of Air
36
Behaviour of Moist Air
36
Summary of Definitions and Terms
38
The Psychrometric Chart
41
SAMPLE TEST RESULTS AND CALCULATIONS
44
Observation Sheet
4S
Derived Results
46
SPECIMEN CALCULATIONS
47
Calculation of Air Mass Flow Rate
Application of Energy and Mass BalancesbetweenA and B
Boiler - Theoretical Evaporation Rate
D
3S
47
47 .
49
Refrigeration System
50
Application of Energy and Mass Balancesbetween B and C
53
Volumetric Efficiency of Compressor
55
Application of Energy Balance between C and 0
56
To Oetennine the Specific Heat Capacity (Cp) of Air
58
SPECIMENS
61
Observation Sheet
61
Derived Results Sheet
62
A660A DIGITAL TEMPERATURE
UPGRADE KIT
63
Operation
6S
Maintenance
6S
A660B RECIRCULATING
Schematic Diagram
Introduction
Description
DUcr
.
UPGRADE KIT
67
70
72
73
I ~f:
'.':
~~I!
I
(v)
~
In Duct Orifice Calibration
Operating Procedure
Wet Bulbs
Degreeof Recirculation
SampleTest Resultsand Calculations
AC660A COMPUTER LINKED UPGRADE and AC660B SOFfW ARE UPGRADE
Introduction
APPENDICES
A: A660A Digital Temperature UpgradeKit Installation Instructions
B: A660B Recirculating Duct Upgrade Kit Installation Instructions
C: AC660A Computer Linked Upgrade Kit
D: AC660B Software Upgrade
E: A660C PID Control Upgrade Kit
F: A660D Environmental Chamber UpgradeKit
75
76
76
76
77
83
85
2
SYMBOLS AND UNITS
Symbol
Quantity
Fundamental
--
!l!!i!
A
Area
H
Enthalpy
h
SpecificEnthalpy
Current
lit
MassFlow Rate
P
Power
p
Pressure(Absolute)
Q
Heat Transfer
Q
R
Heat Transfer Rate
W
Electrical Resistance
Q
Temperature(Customary)
°C
m2
J
J kgA
kg Sol
W
. N m-l or Pa
J
v
Specific Volume
x
Time Interval
mJ kg"
s
Orifice Differential Pressure
.
Relative Humidity
J1
PercentageSaturation
CJ)
Specific Humidity
l\
.Note:
mrn H2O
Changeor Difference
Bar = 105N mo:= 105Pa = 100 kN mo]
Presentationof Numerical Data
In this manual, numerical quantities obtained during experiments,etc., are expressedin a nondimensional manner. That is, the physical quantity involved has beendivided by the units in which
it has been measured.
As an example:
p
This indicates that
or
alternatively
=
150
loJ Nm-2
p = 150 x I ij3 N m-2
p = 150 kN mol
0
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it
7
INTRODUCTION
Air Conditionlne
Air Conditioning, which may be described as the control of the atmosphereso that a desired
temperature, humidity, distribution and movement is achieved, is a rapidly expanding activity
throughout the world.
Obvious applications for air conditioning are homes,hospitals,public meeting places,mines, shops,
offices, factories, land, air and sea transport, but there are numerous other applicatiQnsin which
human comfort is not the prime consideration. These include textile and printing industries,
computers, laboratories, photographic and pharmaceutical industries, manufacture, inspection and
storage of sensitive equipment, horticulture, animal husbandry, food storageand many others.
Air Conditionine Plant
Air conditioning plant usllally consistsof a numberof components(e.g. fans, filters, heat exchangers,.
humidifiers, etc.) enclosed in a sheet metal casing. Intake to the plant is usually from a clean
external atmosphere(plus, in some cases,air recirculated from the building) and delivery from the
plant is via ducting to suitable distribution points. Alternatively small self-containedpackagedunits
may be used to air condition individual rooms or enclosures.
Components
f1!!m-
Coarse
- usually wire mesh. To remove insects,leavesand other large.
airborne particles.
"
Fine-
~-
paper or viscous or electrostatic type.
airborne dust.
To removemost of the
are required to cause the air movement and to make good the pressuredrop
due to the duct and system resistances.
HeatExchan2er5
- which usually are finned on the air side, are neededto increaseor decreasethe
air temperature.
Heaters may use stearn,hot water or electricity as the heating medium
Coolen may be supplied with chilled water or may be of the direct expansion
type in which liquid refrigerant boils at a low temperature within the heat
exchanger.
Humidifiers-
are used to increasethe moisture content of the air. Water may be sprayed
directly into the air, may be evaporatedfrom a moist surface,or alternatively,
steam may be injected into the air. The latter also results in heating of the air.
Dehumidifiers-
are used to reducethe moisture content of the air. This is usually achievedby
cooling the air below its dew point so that surplus moisture is precipitated.
Sometimeshygroscopicmaterialsare usedto achievedehumidification, but, of
course, these require regeneration.
Eliminators-
are speciallyshapedbafflesthroughwhich the air flows and which remove
entrainedwaterdropletsfrom the air stream.
~-
are employed to blend two streams of air to achieve a desired condition and/or
economy.
~
."'"
W",";,
'r!ijr:
,
c',',
:
;
8
..-
Instruments
and Controls
are neededto sensethe condition of the air at various stations, and to vary the
output of the componentsto bring about the desired final condition. In many
installations these may fonn part of a total building
system.
energy management
AssociatedEauiDmentmay include:
~
-
for humidification and/or for the air heaters.
Refri2eration Plant - for the air coolers/dehumidifiers.
HV2rometers are instrumentsfor measuringthe,moisture.content of the atmosphere.
There are many types of hygrometerranging from the paper hygrometerwhich relies on the change
of dimensions of vegetablematter with moisture content, to electronic sensors.
Electronic sensorsusually operate on a capacitive principle. Two electJically conducting surfaces
are separatedby thin insulating material. This fonns a capacitor in an electronic circuit.
The insulating material used is hygroscopic(absorbswater) and changesvolume dependingupon its
water content. This changein volume affects the thicknessof the material :md hencethe capacitance.
The change in capacitanceis sensedby the electronic circuit and this gives an output that may be
sensedby additional electronics and displayed digitally or sent to a computer.
Unfortunately such sensorsare relatively expensiveand have limited accuracy(of the order of:!:3%
RH). While this is acceptablefor general purposes, it is not sufficiently accurate for use with the
Hilton Air Conditioning Laboratory Unit A660.
The Hilton Air Conditioning Laboratory Unit employs the well kno\\n wet and dry bulb type
hygrometer for detennining air condition. This is the most accurate method and is still used in
whirling hygrometers which fonn the standardby which other sensing methods are compared. A
brief description of the operation of the wet and dry bulb sensors used on the Hilton Air
Conditioning Laboratory Unit A660 are given in this manual in the Theory section.
.
,
Comfort Conditions
All animals consumefood (Chemical Energy),do work and reject most ot the unusedenergy to their
surroundings principally to the atmosphere.
-
A manrejectsup to about400W (accordingto his level of activity) to tl-.eatmosphere.This heat
loss is accounted for by a combination of convection and radiation from his body surfaces, and
evaporation of moisture from his lungs and skin.
As the air temperature increases,the amount of heat which can be rejected by convection and
radiation decreases,thus the evapordtioncomponent must increase. If the relative humidity of the
atmosphereis already high, evaporation will be sluggish, skin surfacesb~ome wet, and the person
feels uncomfortable. In hot ~ humid conditions, personnelare quickly exhaustedand are unable
to maintain vigorous activity. In addition, theseconditions favour the growth of moulds and fungi some of which causeskin ailments.
:
Very low humidities on the other hand.causerapid evaporationfrom the lungs, throat, eyes,skin and
nasal passagesand these can also causediscomfort.
Human Comfort
Depending upon their physical activity, clothing and surroundings,most people are comfortable in
gently moving air (free of draughts) which is at about 20°C and which has a relative humidity of
:
..
~_.
.f;'
'i\
...
9
about 50%. However, there is considerable variation of what is considered comfortable between
individuals and betweennations, and in any case,there is a zoneof temperatureand humidity around
the "ideal" which is acceptableto most people. The prime function of many air conditioning plants.
is to provide a comfortable environment in terms of air freshness,temperature, humidity and
movement.
The Hilton Air Conditioning Laboratory Unit A660 allows the processesgoverning air conditioning
to be demonstratedand investigated. It also allows studentsto investigate the measurementand
calculation of all the thermodynamic processesinvolved in the heating, cooling. humidification and
dehumidification of air.
With the addition of optional items the A660 may be expandedto allow demonstrationand
measurementof the mixing of tWo air streams,electronic thermometry,computeriseddata acquisition
and environmental control.
The Hilton Air Conditioning Laboratory Unit A660 and its optional extra componentsare a valuable
teaching aid for students in a wide range of courses from technician to graduate level.
t
10
OPTIONAL UPGRADES:
The baseunit has a straight-through duct. Product description:
A660 Air Conditioning Laboratory Unit
The supplied unit will have a product code:
A660220 for electrical supply 380/415 Volts, 3 Phase+Earth+N (5 wire supply) 50 Hz.
OR
A660110 for electrical supply 200/220 Volts, 3 Phase+Earth (4 wire supply) 50/60 Hz.
Both units use single-phasecomponents,but require 3-phasesupplies. The total current exceeds
normal single-phasecapacity.
The loads on the S-wire model are between Line and Neutral 220/240Y.
The loads on the 4-wire model are Line to Line 200/220Y.
Installation of the 200/220V 3-phase(4 wire supply) 50/60 Hz model includesthe correct positioning
of a wire in the compressorstep-up transformer. Full details appearlater in this section.
The following upgrades may have been received, if ordered together:
AC660A Computer Linked Upgrade (Factory Fitted)
or AC660A Computer Linked Upgrade Kit (Supplied in kit form for installation on site)
Installation instructions are contained in Appendix C of this manual.
AC660B Computer Linked Software Upgrade (Supplied on disk)
Software installation instructions are contained in Appendix D of this manual.
A660A Digital Temperature Upgrade Kit
(Shipped in individual packing case,accompaniedby packing list)
Installation instructions are contained in Appendix A of this manual.
A660B Recirculating Duct UpgradeKit
(Shipped in individual packing case, accompaniedby packing list)
Installation instructions are contained in Appendix B of this manual.
A660C
pm Control Upgrade(Factory Fitted)
or A660C pro Control Upgrade Kit(Supplied in kit fonn for installation on site)
Installation instructions are contained in Appendix E of this manual.
A660D Environmental Chamber Upgrade Kit
(Shipped in individual packing case, accompaniedby packing list)
Installation instructions are contained in Appendix F of this manual.
11
ORDER OF INST ALLA TION WHEN RECEIVED WITH OPTIONAL
factory fitted):
UPGRADES (not
:;tj\;.,:
d-,,:
~~,
12
Remove the unit from its packing case and examine it for damage in transit.
contact the insurers without delay.
If damage is found,
~
The Air Conditioning Laboratory Unit dissipatesto its surroundingsa maximum of about 6 kW of
sensible heat plus 4 kW as latent heat (water vapour) and has an air delivery of about 0.13 m3s'l.
It is desirablethat the intake conditions should be constant,thus, the unit should be placed in a room
with sufficient volume and ventilation that ambient conditions are not materially changed when it
is operating.
The unit must be positioned so that there is no obstruction to the air inlet or to the air flow through
the condenser.
ACCESSORIES:
C30/2S
PF20/2
CS7/8
C30/14
CIO/2
C30/18
A660/6/1
A660/6/2
R633n/1
R633n/2
2
2
I
I
I
I
I
I
I
I
A66on/1
SFI/SS
SF3/2
I
12
12
SFI/S6
C20/24
IM3/2
1M12/8
12
4
4
4
Rubber Stopper,25mm dia.
300mm Spirit in Glass Thennometer, 0 to 50°C
IM3/5
2
150mm Spirit in Glass Thennometer, 0 to 50°C
Reinforced Supply and Drain Hose, 15mm push fit
Stem Elbow, 15mm
RI34a PressureEnthalpy Diagram
R 134aThennal PropertiesTables
EncapsulatedPsychrometricChart, SI units
PsychrometricTables, 700 to 1100 mbar
SchematicDiagram, A3
SchematicText Diagram, A4
A3 SchematicHolder
A4 Schematic Holder
Dust Cover
M6 SS Washer
M6 Nylon Washer
M6 x 25 Hex Head Bolt
Wet Bulb Spirit in Glass Thennometer, 0 to 50°C
IM3/6
I
150mm Spirit in Glass Thennometer, -10 to +1 10°C
AS71/4/1
1
Water Measuring Cylinder
C4S/3
A660/IO/I
I
I
CompressorCharging Valve Key
10/1lmm Open Jaw Spanner
LAJ/184
AS74/37/1
C20/4
I
1
I
E38/4S
I
Unpacking Case Label
Evaporator Gasket
Hose Clip, 13 to 20mm
8mm Nut Runner
SF20/l
2
M6 Plastic Fluted Nut
Set of Manometer Accessories(Fluid, filling syringe, scales)
Product Envelopecontaining:
Experimental, Operating and MaintenanceManual
Test Sheet
Packing List
Wiring Diagram
13
Installation
Remove complete unit from packing case and check with Packing List
Before discarding any packing material ensurethat all items are identified and checkedagainst
the Packing List. Ensure the Sparesare also identified.
2.
3
4
Detach the downstream duct from its storage position under the main duct. Examine the two
wet
bulb to
water
reservoirs
andofrefer
to Figure
7fitting
on Page
22. toIf the
necessary
reservoir
the correct
height
I OOmm
~
the duct
unit. set.the internal
Remove
the bolted supportangle from the evaporatorlower flange and put to one side for
refitting later.
-
Fit the rubber evaporatorgasket(AS74/37/1) and downstreamduct to the evaporatorflange using
the M6 x 2Smm hex head screws (SFI/56) and M6 washers(SF3/2) provided. Refer to Figure
I on Page 14. Refit the lower support angle on the outside of the duct flange.
Ensure that the flange is not over-tightened as damage to the evaporator flange will result.
Ensure that the flange is tightened evenly.
6.
Ensure that no powcr connection has yet been made.
Refer to the wiring diagrams supplied in colour and Figure 2 on Page 1S for 220V 3ph SO/60Hz
units (Drawing No 6602SM) and Figure 3 on Page 16 for 41SV 3ph SOHzunits (Drawing No
66O22M).
.
The 2 x I.OkW re-heaters and duct thennostat in the downstream duct are connectedto the
cables in the loose flexible conduit leading from the control panel. Note that the cables are
marked with numbers that correspond to the wiring diagrams in Figures 2 and 3.
Locate the appropriate wiring diagram for the unit and in Area 2A of the diagram locate the
I.OkW Air Heater(First Reheat)and I.OkW Air Heater(SecondReheat). By convention the first
reheater is closest to the fan.
Using the 415V 3ph 50Hz wiring diagram, Figure 3, as an example. Connect the red wire
labelled 253 to one side of the 1.0kW Air Heater(First Reheat). Connect the black wire labelled
254 to the other side and ensure that the black link 254 to 257 is made between both heaters.
Connect the red wire labelled 256 to the remaining tenninal
A connector block fitted to the downstream duct allows the earth lead from the heaten
(green/yellow stripe) to be connectedto the earth lead in the conduit 255.
Connect the wires labelled 251 and 252 to the thennostatas shown in the diagram
Note that for operator safety it is essential that the earth leads are connectedconectly.
Connection of the heaters for the 220V 3ph SO/60Hzunits are carried out in a similar manner
with reference to the diagram, Figure 2. Note that in the caseof 220V 3ph SO/60Hzunits the
heatersare connectedbetween phasesand connectionsto both ends of the heatersare red. The
correct cable numbers should always be observed according to the diagram.
Finally. fit the plastic terminal cover to the duct with the hex head screws provided
NI
~
\D
\D
~
>
0
N
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18
3Ph 60Hz Machines ONLY
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CONNECTINCOMING
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200/220v
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220V Joh SO/60HzMachines only
The condensing unit supplied is suitable for operation on BOrn 50Hz and 60Hz electrical
supplies. However, it is only available for operation on 220/250 Volt supplies. Therefore a step
up transfonner is provided to increasethe voltage supplied to the condensing unit (ONL Y) to
a suitable value.
The transfonner is located on the lower frame adjacentto the condensing unit itself. Refer to
Figure 4, Page 17.
Remove the screws securing the transfonner cover and locate the brown wire. This will be
factory fitted to the 230V input tenninal of the transfonner.
It will be necessaryto measurethe line' to linez voltage of the local supply. This should only
be undertaken by a competent person.
Once the local line to line voltage has beenmeasured,connectthe brown wire to the transfonner
tenninal that correspondsas close as possible to the measuredvalue. Replace the transfonner
cover and securewith the original screws.
8
-
nov Joh SO/60HzMachines Main Wirin2 Connection
If required by the local regulations, the following should be carried out by a competent
electrician.
Refer to the wiring diagram 6602SM and the detailed view of the main switch enclosure,Figure
S on Page 18.
The unit can draw up to 32 Amps on each phaseand the supply conductors should be sized for
this current according to the local regulations.
Remove the main switch and enclosure cover to gain accessto the terminals
Connectthe three lines (LI, L2, L3) and the earthing conductor(E) as shown in the main switch
diagram. Strain relief for the supply cable or suitable conduit should be titted according to the
local regulations.
For operator safety it is essentialthat a low impedanceearth of adequatesize is connectedto the
unit earthing tenninal.
Refit the main switch and cover.
440V Joh 50Hz Machine!
If required by the local regulations, the following should be carried out by a competent
electrician.
Refer to the wiring diagram 66022M and the detailed view of the main switch enclosure, "igure
6 on Page 19.
The unit can draw up to 20 Amps on each phaseand the supply conductors should be sized for
this current according to the local regulations.
Remove the main switch and enclosure cover to gain accessto the tcrminals
Connectthe three lines (LI, L2, L3) and the Neutral (N) and Earth to the main switch as shown
in the diagram.
For operatorsafety it is essentialthat a low impedanceearth of adequatesize is connectedto the
unit earthing terminal.
Refit the main switch and cover
21
9,
Water Supply
The boiler requires fresh water (if possible distilled or de-mineralised)at a maximum rate of 10
litre/hour with a minireum head of 2m.
The boiler feed point is a I Smm push-fit fining labelled "cold water inlet" locatedbelow the fan.
Connect this to the local water supply via an isolating valve using the water inlet tube assembly
1/1"bore (C30/4) and elbow (PF20/2) supplied in the accessorieskit.
It is recommendedthat when the unit is not in use the locally supplied isolating valve is closed.
Water will not flow to the boiler until electrical power is supplied to the machine.
Inside the boiler are two electrical level sensersthat control the water solenoid valve.
Connectthe remaining hose to the overflow connection and position thee free end in a floor
level open drain.
Water Overflow
In the unlikely event of component failure, the overflow pipe allows excesswater to flow from
the tank and prevent water entering the air duct. Reducethe level by draining into a receptacle.
The solenoid valve will open again to refill. Note than an open pipe extends from the copper
overflow pipe vertically upwards and ends just below the frame. Do not block this as it is a
syphon break.
To test operation of the unit turn on the electrical supply and the water isolating valve.
Turn on the unit main switch on the instrument panel, seecontrol panel diagram on Page6, and
water will be heard to flow into the boiler tank.
Observethe sight glass on the steamgeneratortank. Water should be seenin the sight glass and'
then the level sensorwill close and turn off the solenoid valve.
10. Instrumentation
The air condition is measured by four pairs of wet and dry bulb thermometers.
The wet bulb thennometers are pre-assembled(IMI2/8) and the dry bulb thennometers are
selected from the O°C to 50°C 300mm thennometers(IM3/2) supplied.
A sectional view of a typical wet bulb station is given in Figure 7 on Page22.
To support the wet and dry bulb thermometersin the duct. rubber discs (C20n4) are supplied
and these are carefully slid over each thermometer from the top down towards the measuring
bulb.
Adjust the height of the rubber discs so that when inserted in the measuring station holes in the
duct the measuring bulbs are at approximately mid duct height.
Tl and 1'2 are retained by thumb screws at the fan inlet.
Th~ accuracyof the wet and dry bulb measurementwill influence the overall accuracyof ~nergy
balancesrelating to the air stream. To ensurema.~imummeasurementaccura<:ythe wet and dry
bulb thermometersmay be calibrated in water by selecting one thermometer as a reference,or
by using a locally available reference.
Nole that the optional A660A Temperature Upgrade Kit replaces all of the thennometerswith
thennocouples and a single switched digital temperatureindicator.
Marking all tht thennometers and recording variations from the reference will then allow
individual variations to ~ addc.'dor subtractedas appropriate from the in duct measurements.
rTt
~
~
~
1
22
A660: CROSS SECTIOr-JOF DUCT THROUGH WET BULB RESERVOIR
t6
V
CR'y 9..lB n£Rr'OETER
NOT St-KJWNFOO CLARITY
CENTRAL
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RESERV~
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RESERVOR
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,
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WET aJLB RESERV~
FIGURE 7
~
23
It is recommendedthat the wet bulb thennometersare kept wet when not in use to prevent the
wicks drying out. This is best achieved by keeping the wet bulb reservoir full to its minimum
level.
The wet bulb reservoir should be connected,then filled with distilled or demineralisedwater so
that scale depositsdo not build up on the wick material. Replacementwick material is supplied
for future use (RMX8/2).
The refrigeration system thermometer pockets (13, 14 and 15) are designed to accept either
1SOmmO-SO°Cthermometers(IM3/S), or -10 to + 110°Cthermometers(1M3/6). The appropriate
thermometer for the three measuring stations will depend upon the local conditions and the
conditions establishedin the air duct. If the red spirit reachesa temperaturenear the top of the
O-SO°Ctube then insert the higher l:al\ge theanometer.
II.
Manometer
Remove the blanking caps from the two manometer tubes and retain for future use.
Connect the grey plastic tube supplied to the tapping point on the side of the downstreamduct
and to the left hand tapping on the manometer.
When the unit is in its final position in the laboratory, adjust the manometer level by releasing
the right hand mounting screw and adjusting according to the integral spirit level.
With no air flow adjust the knurled nut on the right hand manometertapping until the red fluid
is at the zero mark.
12. Fan Speed Adiustment
Refer to Control Panel Schematic, Page 6. Switch on the power supply to the unit. Check all
control panel s\vitches are otTo Isolate the water supply.
Rotate the fan speed control fully clockwise to maximum speed. Switch on the main switch.
The main solenoid will click and the fan will start. Reduce fan speed to the minimum stop
(fully anti-clockwise) and observe manometerscale. It should be approximately 3mm HID or
more.
The following should only be carried out by a competent person as the adjustment has to
be carried out with the power switched on.
~linimum fan voltageis adjustableby meansof a singletrim potentiometerfitted to the Fan
SpeedControl insidethe control panel. The controlpanelhingedlid mustbe openedto gain
accessto the inside. CAUTION - LIVE ELECTRICS!
Locate the potentiometer on the fan speedcontrol circuit board. This is a squareplastic device
approximately 2cm x Icm x O.5cmwith a small brassscrew head on the top.
With the Fan Speed Control in the minimum (fully anti-clockwise) position, rotate the
potentiometer to vary the fan speed to achieve 3mm H2O duct pressure.
Before closing the control panel, take this opportunity of testing the RCCB in accordancewith
the instructions listed in the MAINTENANCE section.
The installation is now complete
24
DESCRIPTION - THE HILTON AIR CONDITIONING
(Pleaserefer to Sthematic Diagram, Page4)
LABORATORY
UNIT A660
Note that optional upgradesA660A Digital TemperatureUpgradeKit and AC660A ComputerLinked
Upgrade Kit. and the item label numbers are shown.
With the exception of filtration and mixing, the Hilton Air Conditioning Laboratory Unit has been
designedto demonstrateand to evaluatethe energy transfersoccurring in all the processeswhich are
required in an air conditioning plant.
The unit is mounted on a mobile frame which housesthe refrigeration unit and stearngenerator
Untreatedair entering the ducting passesin seri~ through
2.
3
4
6.
An axial flow radial fan with speedcontrol (9) and (10).
Steam can be added by a steam injector after the fan discharge(3).
A pre-heater(4).
A cooler/dehumidifier with a precipitate water outlet (5) and (22).
Are-heater (6).
An air measuring duct orifice (7) and manometer(14).
The arrangementof a pre-heaterbefore the evaporator/coolingcoil is I.ot standard air conditioning
practice, but the heater has been included at this point close to the !i.earn injector for a specific
teaching purpose.
If the local relative humidity is close to saturation, injection of steam can simply result in the duct
running with water as the air cannot absorb more vapour than that required to saturateit at the given
dry bulb temperature.
The addition of sensibleheat as well as the steam raisesthe dry bulb temperatureand takes the air
away from the saturatedcondition to a lower Relative Humidity.
Similarly, the location of steam injection before the evaporator/cooling coil is not normal for air
conditioning where humidity control is required. This would usually be located after the
evaporator/coolingcoil. However, in locations where the relative humidity is very low, the ability
to demonstratethe de-humidification processwould be impossible. Therefore by injecting steam
before the evaporator/cooling coil the relative humidity of incoming air can be raised close to
saturation so that dehumidification &nd the mass transfer processcan iJe demonstrated.
In caseswherethe humidity and temperaturecontrol upgrade(A660C) is purchased,the stearn
injectoris relocatedto a pre-installedpoint after the evaporator/cooling
coil.
With the physical arrangementdescribed above and by selection of the individual heaters.steam
injection and refrigeration/cooling system, the following data may be readily obtained:
(a) The condition of the air before and after the various processes(via wet and dry bulb
sensors).
(b) The energy transfer rate at each heater,the boiler, fan and refrigeration unit.
(c) Air mass flow rates.
(d) Pressuresand temperaturesof refrigerant.
(e) Refrigerant mass flow rate.
(f) The generation of a refrigeration cycle diagram on a pressure-enthalpy chart for the
refrigerant in use. The analysis of the energy transfers in the refrigeration system.
(g) Rate of precipitation at cooler.
This infonnation, combined with thc use of air and refrigerant tables or charts. enables the operator
to demonstrate and evaluate all the effects likely to be met in an Air Conditioning Plant. The unit
is also an excellent vehicle for demonstrating energy transfers in steady now processessince it
includes heating. cooling and work transfer (at the fan).
,
~
25
SPECIFICATION
Duct
Centre line length:
A660
A660B
A660B
= 2298mrn
= 6098mm 100% fresh
= 6886mm 100% recirc.
Material: PVC
Thermal conductivity: 0.16 W/mK
Maximum temperature:70°C
Air Throughput
0.14 m3 s.t (max)
Pre-heater
Extended fin electric heating elements. 2 x 1.0 kW (nominally) at
220V
.
Effective iength: 1.414m
Exposedtubesurfacearea:0.0355m
2
Exposed fin surface area: 0.2876m2
Cooler
Direct expansion,extendedfin coil. Cooling rate approx. 2.0 kW
51S"o.d. copper tube, 20swg.
4 rows deep x 5 rows high: 0.253m1exposedto air flow.
61 fin plates: 4.227m1exposedto air flow.
Re-heater
Extendedfin electricheatingelements. 2 x 0.5 kW (nominally)at
220V
Effectivelength:1.414m
Exposedtubesurfacearea:0.03SSm1
.
Exposed fin surface area: 0.2876m1
Fan
Centrifugal (variable speed). Power input approx. 120W, at 240V
50Hz.
R.P.M.: 0-2400
Power: 0-0.9A, 210W
Volts: 220-240
Humidifier
Electrically heatedand working at atmospheric pressure. Fitted with
water level float switch and in line solenoid valve.
Heaters: I x 1.0 kW and 2 x 2.0kW at 220V (nominally).
Volume: 2.5 litres (to mid-sight glass) under control of level control
float switch.
Overflow protection: A secondfloat valve will open circuit at 4 litres
in the event of failure of the level control float switch.
Water Solenoid Valve:
Orientation: Any
Inlet Pressure:0-45 bar
Power Consumption: 19vA
Refrigerator
INSTRUMENT A TION
Air Flo\v
Measurement
Hennetic unit with air cooled condenser.
Refrigerant: R 134aTetrafluoroethaneCFJCH2F
Compressorspeed: 2700 to 3000 rev.minl at 50Hz. according
to load. 3300 to 3600 rev.minl at 60Hz.
Swept volume: 25.95 cmJ rev'l.
- A660 (with no optional uDllrades)
Orifice plate with inclined tube manometer.
Range: O-12mm Water
.
26
Temperature
Measurement
4 pairs Wet and Dry Bulb glass thennometers300mm long.
Refrigerant
Circuit
3 x 300mm Glass thennometers.
SAFETY
Refrigerator high pressurecut-out.
Temperature limit (50"C) thermostatsat the pre-heaterand re-heater
stations.
.
All moving parts are enclosed.
All electrical components are individually switched by miniature
circuit breaker switches to protect against overload and short circuit.
The unit is protectedby a ResidualCurrent Circuit Breaker which cuts
off the power should the current in and out differ by more than 30mA,
as in a leakageto earth situation
To ensure heaters are not switched on without air flowing, the fan
speedregulator is pre-set to give an adequateair flow as soon as the
three phasemains switch is closed.
SERVICES REQUIRED
Electrical
Either
Or
380/440 volt, 3 phase,50Hz. 5 wire system comprising
3 phases,neutral and earth.
Typical line currents can be up to 20 Amps per phase.
2. 208/220 volt, 3 phase, 50 or 60Hz. 4 wire system
comprising 3 phasesand earth.
Typical line currentscan be up to 32 Amps per phase.
Water
Approximately 10 litre per hour at a minimum head of 2m. (To
reduce scaling in the boiler this water should, if possible, be distitled
or de-mineralised.) Note this can be a smatl reservoir specificatly for
the unit and does not have to be a mains supply.
.I
27
USEFUL DATA (see also.Specification)
Note:
For 380/440V 3ph. 50Hz. machines, the heaters are connected line to neutral and the heater
voltage may be between 220 and 254V.
For 200/220Y 3ph. 60Hz. machines, the heaters are connected line to line and the heater voltage may
be between 200 and 220Y.
The fan power input can be detennined from the graph (Figure 12) on Page 48 relating the Fan
Power Consumption to Supply Volts.
The specificheatof air Cplir = 1.005kJ kg" 1<'\
The specificheatof waterC,Hel\t loss from boiler: 1.33~
I<
= 4.18 kJ kg" 1<,1
(SeePage35)
~
ma . 0.0517
Orifice calibration:
kg$-1
~ VD
Where, Z = Orifice differential (mm H2O)
VD = Specific volume of air at Station D (from psychrometric chart)
Compressor swept volume: 25.95cmJ rev"
Compressor speed: 2700 to 3000 rev.min-' (typical at 50Hz.)
JJOOto 3600 rev.min-' (typical at 60Hz.)
bar =
x 105 N mol
=
100 kN
mol (or
100 kPa) = 14.5Ibf in2
Absolute pressure = Gauge pressure+ Atmospheric pressure
Standard atmosphericpressure = 101.3 kN m-z(1013 mbar)
lkW
= 3412 Btu h-'
28
OPERATION
(Pleaserefer to Schematic Diagram, Page4, and the Control Panel Diagram, Page 6)
Check the wet bulb reservoiris filled to the level mark.
Turn on the water supply to the boiler and supply power to the unit. Turn on the main switch on
the left of the control panel and the water solenoid valve will be heard to open. (In addition, the fan
will run as soon as the main switch is turned on.) The panel voltmeter will indicate supply volts L I
to N (415Y units, or LI to L2 (220V units).
Ensure that water is visible in the sight glass of the steam generator before turning on any of the
steamgeneratorwater heaters.
.
The eight switches on the control panel are combined double pole switches and miniature circuit
breakers. These control all of the heatersand the compressorof the refrigeration systemas indicated
by the labels on the panel.
The MCB button on the left of the control panel (or two buttons in the caseof a 220V 3ph SO/60Hz
unit) protect the fan supply from overload conditions. If the buttons protrude from their normal
position then a fault condition will be indicated and the causeshould be investigated. It will also
open circuit the supply to the main magnetic contactor. The unit is therefore shut down when the
fan MCB is tripped.
To reset these circuit breakerssimply press the button back in.
Note that if the fault still exists the button will not remain in a locked position.
ill
On the left of the control panel is the fan speedcontrol. Turning the speedcontrol clockwise will
increasethe fan speed.and anti-clockwise will reduce speed.
Pressingthe biased switch will causefan volts to be displayed by the voltmeter.
Note that the minimum pressureindicated by the manometershould not drop below 3mm water
gauge when the fan speed control is fu\Jy anti-clockwise. This should be set as part of the
(nsta\Jationand Commissioning procedure. See Fan SpeedAdjustment, Page23.
Obtainin2 Stable Conditions
The unit should be started according to the above procedureand, dependingupon the parametersto
be investigated,the appropriate controls turned on or adjusted.
The time taken for the unit to stabilise will vary dependingupon the local ambient conditions. This
can vary from 10 minutes to 20 minutes.
The humidification processcan be started more rapidly if all the water heatersare turned on until
the water is boiling. Then turn off the heatersthat are not required.
Note that the refrigeration plant will not begin to stabilise from initial start up until the refrigerant
shown in the variable area glass flowmeter is a column of liquid without bubbles.
When changesare made to the conditions upstreamof the evaporator.the refrigerant flow rate will
be seento alter due to the increasedor decreasedheat loadi~g.
29
Shuttin2 Down After Use
Before switching ofT:
(a) Switch off all boiler heaters.
(b) Switch off all air heaters.
(c) Switch off refrigeration circuit.
(d) Set the fan to maximum speed.
Then allow the fan to run for at least five minutes to dry the ducting, after which the main switch
and isolator may be switched off.
Turn off the locally supplied water isolating valve and drain the steamgeneratorto reducescalebuild
up.
Icin2 at Evaoontor
At low air flow rates, accompanied by low ambient temperature, it is possible for the R134a
evaporating conditions to fall below O°C/300 kN moJ.
If this happens, it is probable that ice will fonn on the air side of the evaporator tubes and fins and
on the expansion valve.
While no damage is likely to occur if operated in this condition for a few minutes, it is inadvisable
to operate in this condition since the ice will eventually stop the air now.
Icing can be avoided by increasing the air flow rate and/or switching on the air pre-heaters.
Hi2h Pressure Cut-Out
If the condenserpressureexceeds 1400 kN m-2gauge(e.g. due to restriction of cooling air flow), a
high pressurecut-out will switch otTthe refrigeration compressor,but the air fan will continue to run.'
The high pressurecut-out is adjacent to the compressor.
When the condenser pressure has fallen to about 800 kN m-1 gauge, the compressor will
automatically re-start if the control panel switch is still in the On position-
Hieh Temperature Cut-Out (In Duct)
In duct thennostats are !ocated at the pre-heater and re-heater stations to limit the maximum
temperature to 50°C. In the event that this temperatureis exceededthe main contactor relay will
open, turning off the power to all of the heaters(boiler, pre-heater and fe-heater). The fan will
continue to run and so help to cool the duct.
Once
the temperaturehas reducedat both thennostats,the main contactor relay will close and supply
power to the heaters.
Hi2h Temperature Cut-Out (Steam Generator)
The three heater elements fined to the stearn generator are fined with automatic reset high
temperature cut-out devices. In the event that the user forgot to turn on the water surply to the
steam generator the elements would boil dry and overheat. The thermostatswill turn off the power
at the heater and prevent a dangeroussituation developing.
The thermostatswill operate more than once, but it is not recommendedthat the situation is allowed
to occur repeatedly as Ihe healers will eventuallv fail.
30
r!!
RECOMMENDED TEST CONDITIONS
Provided the air temperatureis not allowed to exceedSOOC,
any operating conditions may be used.
However, satisfactory results are more likely to be achievedif the following points are noted
(a) l~umidification
When humidification is required, the rate of steam injection should not exceed that which. can
be absorbedby the air.
If it is found
thatthe
mist
is seen
downstream
of the steam distributor, either,
(i)
Reduce
heat
inputsome
to thedistance
boiler, or
.
(ii)
(iii)
Increasethe air flow rate, or
Increasethe air dry bulb temperatureby switching on more pre-heat.
(b) De-humidification
(i)
When it is intended to demonstratede-humidification, the air should be fairly humid
(say. 650/.)at Station B. If necessary,steam may be injected.
(ii)
The cooler hasa large surfaceareaon which the condensationtakes place. Due to this,
an appreciabletime elapsesbefore condensateis dischargedfrom the drain at the same
rate as it is precipitated.
(iii)
The changeof moisture content of the air is easily determined from the product of the
air massflow rate and the changeof specific humidity. Agreement between this, and
the drainagerate wilt be obtained after a sufficient period under steady conditions.
Unit Caoabilities
As shown in the following observations and specimen calculations, the Air Conditioning Laboratory
Unit may be used to demonstrate and evaluate energy and mass balances in most of the processes
found in practical air conditioning plant, (i.e. heating, cooling, humidification, and de-humidification).
In addition. the unit may be used:
(i)
(ii)
To detennineCp for air. (FromQ = ri1 Cp t\t. when 0) is constant)
To provide a hot, cold, humid or dry condition under which articles may be placed. (The
article must be capable of insertion into the duct through the orifice plate.)
To estimatethe volumetric efficiency of the compressor
To draw the cooling curve for a boiler and estimate heat loss at various temperature
differences.
Ener2v Transfen
All the processesin the Air Conditioning Laboratory Unit may be treated as steady flow processes
with insignificant changesof kinetic and potential energy.
Thus. for any portion of the unit treated as an open system
Q-P=4H
L\H is the enthalpy rate(s) of the nuid(s) leaving enthalpy rate(s) of the fluid(s) entering
~
31
Q is the heat transfer rate (positive if ill the system)
it is the work tra.'1sferrate (electrical or mechanical)(positive if
f!:Q!!!,
the system).
"'
1I .::
'
rE..\I~
!!; ~
it'.t
32
MAINTENANCE
,"~l
r'
;
:!~II
i
WARNING:
I'
I!:
.
"
Earth Leaka2e Testin2.
Due to local legislation some establishmentsmaintain a register of electrical appliancesand subject
them to periodic tests for earth leakageand earth continuity.
Before conducting
anysupply
fonn oftotest
will subject
the unit
or its components
abnonnal voltages,
disconnect
the power
thethat
following
optional
components
if they aretofitted:
'
A660A Digital TemperatureUpgrade
AC660A Computer Linked Upgrade
The digital temperatureindicator in the A660A kit and the data logger in the AC660A kit are both
plugged into a 4-way socket at the rear of the unit. Unplugging them will disconnectthem from the
system
These components are likely to be permanently damaged if not disconnected before the other
components of the A660 are tested.
Befri2eration Circuit
The refrigerant circuit was correctly charged with approximately .4 kg of R134a before it left the
P.A. Hilton Ltd., works.
If it is found that there is continuous gassing in the R 134a flowmeter it is possible that a leak has
occurred.
The refrigeration condensingunit is of a standardand widely used type. It can be serviced by any
goodrefrigerationcontractor.
Note that the unit should not be charged with any refrigerant other than.Jot;~~::
"Drop in" replacement or alternatives are.!!Q! suitable for use with this ~~Z~
~
~134a).
The unit contains sufficient Ester oil for its lifetime operation. Do not add any oil to the refrigerant
circuit.
Leak Detection
(i) Assuming that the refrigerant pressuregaugesread aboveatmosphericpressure,leaksare readily
detectedby normal methods,e.g. electronic leak detector, or soap solution.
Note that electronic leak detectorspreviously used for detecting CFC12 are often not suitable
for detecting leaks of HFC134a. Check with the leak detector supplier for their suitability.
(ii) If the refrigeration circuit is completely discharged,the systemmay be pressurised(through the
charging valve) to about 600 kN m-2gaugewith dry nitrogen. Having located and rectified the
leak, the refrigeration circuit must be evacuatedto IOmm.Hg.Abs.to ensureno moisture exists
in the circuit, before it is re-charged.
Always slacken the gland nut before turning the service valves. Retighten after movement. A
10/11mm open jaw spanneris provided for this purpose.
Re-chareine
Having establishedthat there are no leaks in the circuit, a cylinder of Rl34a should be connected
to the charging point in the compressorsuction line. Purge the connecting pipe with R 134abefore
tightening the connection to the compressor.
33
Turn the back seating valve spindle on the compressorsuction line two turns clockwise and allow
the pressure in the system to rise to about 600 kN mo2.then switch on the compressorand allow
refrigerant to flow into the circuit. Only R134a gas (not liquid) must be allowed to enter the system
(i.e. the valve on the R13'~acylinder must be at the top).
The charging processshould be interrupted at intervals of 2-3 minutes to allow the plant to stabilise.
Continue to charge the circuit until the gassing in the flow meter ceases-and then add a further 0.5
kg.
Back. seat the charging valve and disconnect the Rl34a cylinder. Retighten the glanc;inut on the
service valves and replace the caps.
Cleanine:
.
The air cooled condensermust be kept clean. If dust or fluff is seento build up on the heat transfer
surfaces, it may be removed with a soft brush or with a compressedair jet.
Superheat Control
The superheatcontrol is set to give approximately 3 to 5 K of superheatat normal conditions. If it
is necessaryto adjust this, remove the cap nut from the expansionvalve. Rotatethe screw clockwise
to increase the superheat. Any adjustments must be made with the unit running and in small
increments (i.e. 1,4turn), allowing time for the unit to stabilise between each adjustment. After
adjustment, replace the cap nut.
Manometers
This has been correctly filled and had a sealing cap fitted before leaving our works. The cap must
be removed and the appropriate tube fitted before the manometeris used. If the manometerneeds
re-filling or topping up, the correct fluid (supplied with the unit) should be used. If an alternative
is used, ensure that it has the correct specific gravity as stated on the manometerscale.
Care of Boiler
If distilled or demineralised water is used, the boiler should require little attention.
If untreated water is used:
(i)
It is possible that the heating elementswill require de-scaling after prolonged operation. Local
experience with the de-scaling of the heating elements in electric kettles will guide the user in
this matter.
(ii) There may be a tendency for the water in the boiler to "foam" as the concentrationof impurities
increases.
Foaming will cause the water level in the sight glass to behave erratically and water may be
dischargedwith the steam into the duct. If this happens,switch off the heatersand turn off the
water supply. Drain the water from the boiler through the drain point provided. Then turn on
the water, check that the level rises to the normal position and switch on the heating elements
as required.
The frequency at which the boiler must be drained and re-tilled will be found by experience
it is, of course, advisable to do this before foaming occurs.
Water for Wet Bulb Sensors
It is necessaryto use distilled or demineralised\vater to fill the reservoir for the wicks of the wet
bulb sensors. This is to prevent impurities building up in the wicks and reducing their absorption
properties.
I
II
,
,
§
34
The condensatefrom the air cooling/de-humidifying section may be regardedas distilled water and
can be used for the above purpose.
, '
! !':
If it becomesnecessaryto replacethe wicks on the wet bulb sensors,it is essentialthat the new wick
is in f1rn1thennal contact with the bulb. This is achievedby pulling the wick in an axial direction
(which will cause it to contract circumferentially) and then securing it with heat shrink sleeving
supplied.
T~tinl! the RCCB
The Residual Current Circuit Breaker (RCCB) is situated inside the control panel adjacent to the
power cable connector and main switch.
The RCCB should be testedby a comoetent oerson at intervals as required by the local regulations.
Remove the hex headscrews and open the switch panel. Supply power to the unit and turn on the
main switch. Press the button marked 'Test' or 'T' on the RCCB, but DO NOT TOUCH
ANYTHING ELSE INSIDE THE UNIT. The large lever on the RCCB should turn from the ON
('I') to OFF ('0') position immediately and the unit isolated from the supply. If this does not occur,
the RCCB may be faulty and needsto be repaired/replacedby a qualified electrician.
Return the lever to the ON ('I') position and the unit should be switched on again. Close and secure
the switch panel in position with the hex head screws.
35
DETERMINATION
OF HEAT LOSS FROM BOILER
Note that this can only be undertaken if the A660A Temperature Upgrade Kit has been fitted
or if a thermocouple type temperature indicator is available.
Tape a thennocouple onto the outer surface of the boiler at about the mid water depth.
Switch on the heatersand raise the water temperatureto 100°C.
Switch
(i)
(ii)
(iii)
off the heating elements and then note, at intervals:
The temperature indicated by the thennocouple.
The time
The ambient temperature (tJ.
.
Draw a graphof temperaturev. time, and from this estimatethe rateof cooling(~
whenthe
temperatureis t OO°C.
L\time
Figure 8
From the dimensions of the boiler calculate the mass of water present (mw)' The water equivalent
(mJ of the boiler is 0.54 kg.
Heat loss rate from boiler,
Q
= (m.
+ m.>
x 4180
This is at a temperaturedifference of (100 - t.) K.
Thus,
Typically, for the boiler
Q=
AI
.33 ~
K
(~>
A time
W
36
rI
t"1
I.rI
THEORY
(Note: In the following, "stearn" and "water vapour" are interchangeable.)
~
IIe
ti
I
i
Introduction
Fresh air contains about 23% oxygen and 76% nitrogen by mass. The remainder is composedof
small quantities of other gasesand vapours, and of thesethe most important is water vapour. The
vaponr content of the atmosphereis loosely referred to as the HumiditY.
Although the water vapour content is usually very small, (usually < 2%), it has a considerableeffect
on the rate of evaporation from moist surfacesand materials. An understandingof the moisture
content of the atmosphereand of how it may be controlled is an important part of the education of
all engineersand technologists.
1
:t , .
,1.
:\.,
W.i
Behaviour of Moist Air
Dalton's and Gibb's Laws give us the following conclusions,
(i) Each gas or vapour in a mixture obeys its own physical laws as if it were the sole occupant of
the space, at the sametemperatureas the mixture.
(ii) The enthalpy, internal energy and entropy of a mixture is the sum of the enthalpies, internal
energiesand entropiesrespectively, which each constituent would have if it alone occupied the
spaceat the sametemperatureas the mixture.
Examole (See p-v diagram for steam)
Let us consider air of specific humidity, i.e.
massof steam
mass of dry air
of 0.0I at atmosphericpressureand 20°C. The density of this air will be approximately 1.2 kg mo)
The composition of I.Om} of this "air" will be:
lQ.Q.x 12 =
188 kg of dry air (i.e. the gases)
101
-
x
.2
=
0.012 kg of HzO
101
From Dalton's Law the H2O behavesas ifit was the sole occupantof the space(1.0m3). Thus the
H2O is at 20°C and has a specific volume of:
-L
= 83 m3 kg"
(Point A)
0.012
From steamtables we seethat at 20°C, VI = 57.8 mJ kg-I and P...= 0.0234 bar (2.34 kN m-2),(Point
B). The steam at A is therefore superheatedand at a lower pressurethan 0.0234 bar.
At low densities, water vapour very nearly obeys Boyle's Law, thus
p" V" = PBVB
p" =
0.0234x 57.8 = 0.0163 bar (1.63 kN m-2)
83
In a stearn/air mixture, the ratio
actual ressure 0 steam
pressure of saturated steam at the same temperature
is called the RelativeHumidity (+).
j
37
.
~
..
p
..!;.,
...,. _.2
p - V ~grOIl
for SleoII
\
\
0"°2.34
0016
0.0087
200(
\
~.B
"*
~
0
c
';::::~~:~:;;
5°(
, x. 0.56
~
v
83
578
147
-;Jkg-:r
Figure 9
If our sample of air is cooled, at constantvolume, to 14°C the steamwill just become saturated(v.
= 83m} kg"' at 14°C, Point C).
This temperature is known as the Dew Point.
If the air is cooled, in thennal equilibrium, to a temperaturebelow the dew point, the steam in it
must become wet, e.g. if the steam is cooled to 5°C (Point D) when v. = 147m] kg-I, the dryness
fraction (x) will be y- = .J1 = 0.56
v.
147
Thus, of the 0.012 kg of H2O in the air,
0.56 ;It 0.012 = 0.0067 kg will be saturatedsteam
and,
0.44 x 0.012 = 0.0053 kg will be saturatedwater (liquid).
;tfl'
38
The liquid may appear as mist (i.e. suspendedwater droplets), or as condensationon the cooling
surface.
~:
In this example it has been assumedthat
(i) the air is cooled at constant volume
(ii) the water vapour obeys Boyle's Law
However,the resultsare also substantiallycorrectfor constantpressurecooling over the same
temperature
range.
From the foregoing it will be seenthat if the relative humidity is high, (up to 1000/0)the air cannot
absorbmoresteamunlessits temperatureis raised).
-
The lower the relative humidity, the greaterwill be the readinesswith which air absorbsmore steam.
It is now necessaryto define some tenns of reference.
Summary or Definitions and Terms
Humidity
When an atmospherehasa large water vapour component,(e.g. in a room containing large quantities
of exposedhot water), we say (loosely) that the humidity is high.
Morc clearly defined terms are:
(i)
Absolute or Specific Humidity «I) is the ratio (in a given atmosphere),
moss of water vapour
mossof dry air
(ii)
(~
kg)
Percentap;eRelative Humiditv (cjI)is the ratio,
p. = partial pressure of the steam in an atmospher;;x 100 (%)
p.
(iii)
saturation pressure of steam at the same temperature
Percentae.eSaturation (~) is the ratio,
mass of steam in a given atmoshperex 100
(%)
mass of steam to salUrate the atmosphereat the same temperature
~:
Under nonnal atmosphericconditions, the Relative Humidity=PercentageSaturation(within
1%).
The easewith which the air takes up moisture from any surfaceor processdependsupon how close
the air is to being saturatedrather than its absolutevapour content.
The relative humidity or percentagesaturation is therefore of greater significance than the absolute
Q! specific humidity when drying or air conditioning processesare being considered.
39
Measurementor Air Condition
Dew Poin!
The dew point is the temperatureat which the steamin the air becomessaturatedand therefore
beginsto condenseto a liquid.
Above the dew point the steam in the air is superheatedat a pressure < Pili for the temperature.
Below the dew point the water in the air will be a mixtUre of saturatedsteam and liquid water.
Hence by slowly cooling a polished metal surface and observing when water begins to condenseas
mist, the dew point temperaturecan be determined if the temperatureof the surface is known. The
partial pressureof the steam in the atmosphereat the dew point temperatureis the saturationpressure
of the water vapour at that temperature. Hence if~e know the atmospherictemperatureand the dew
point temperature,we can determine the Relative Humidity with referenceto the Relative Humidity
definition.
For example, if the Ambient temperatureis 20°C and the dew point temperaturehas been measured
as 11°C, from Steam tables
Temperature
20°C
II"C
Saturation Pressure
0.02337 Bar absolute
0.01312 Bar absolute
Relative Humidity = 0.01312 x 100%
0.02337
= 56.1%
.
The measurementof dew point temperature is carried out to measureair condition, but the use of
"wet and dry bulb" temperaturemeasurementis more convenient.
II
Wet and Dry Bulb Temperature Measurement
If a steam of air flows past a temperaturesensor having a wet sleeve of cotton or linen around it,
the temperature recorded will be less than the actual temperatureof the air.
The temperaturefalls due to evaporation from the wetted sleeveand as a result there is a transfer of
heat from the air to the wetted sleeve to sustain the evaporation.
The temperature falls to a steady state value called the wet bulb temperaturewhen the rate of heat
transfer balancesthe loss of energy due to vaporisation.
The actual temperature of the air is sometimes called the dry bulb temperature to emphasisethe
destination.
The lower the relative humidity of the air the more rapid the evaporation from the wet bulb and the
larger the difference between the wet bulb and dry bulb temperature.
When the air is saturated(RH = 100%) the wet bulb, dry bulb and dew point temperatureare the
same.
Since the evaporation.and hencewet bulb temperature,dependsupon the heat and masstransferrates
trom the wetted sleeve, any slight draught increasesthe wet bulb depression. It is found, however,
that though the wet bulb temperature falls for velocities up to approximately 2 mIs, it remains
sensibly constant up to approximately 40 rn/s.
II
40
r
Provided that the air velocity remainswithin this range,the relative humidity can be determinedfrom
the wet and dry bulb temperaturesalone.
The wet bulb temperaturewithin the 2 m/s - 40 m/s air velocity range is often referred to as the
"Sling temperature".
The following equation may be used to determine the vapour pressurePv of the water in the air.
P.
- P., - 101.325
A (t~ - t..,
= Saturatedvapour pressureat tsli.. kPa
= Sling wet bulb temperature
,., = Dry bulb temperature
°C
Where p.,
,.,
;
!
A
°C
= 6.66x I O~K" whentsiinS
~ O°C
= 5.94 x
10'" Ko1when t.sI,n.
< OoC
(Ref. Chartered Institute of Building ServicesEngineers Guide, Volume C, 1988.)
For example, if the dry bulb temperatureis 25°C and the "Sling" wet bulb temperature is 20.6°C,
then,
From Steam Tables at 20.6°C Psi D 2.426 kPa
Hence,
Pw
=
2.426
-
101.325x 6.66 x 10-4(25- 20.6)
= 2.426- 0.2969
= 2.129kPa
From Steam Tables at 25°C
p., = 3./66kPa
Hence, from the definition,
Relative Humidity =
P.
p2.129
x 100%
3.166
67.2%
The above method allows relative humidity to be determined from wet and dry bulb temperatures
and also allows for computerisedmonitoring and calculation of relative humidity.
From Relative Humidity and dry bulb temperature all of the other relevant parameters may be
determined by calculation, from tables or the psychrometric chart.
41
THE PSYCHROMETRIC CHART
While it is possible to calculate the properties of moist air from Dalton's and Gibb's Laws, it is far
more convenient to use the encapsulatedpsychrometric chart provided.
For the majority of situations the standardlarge psychrometricchart supplied in the spareskit (Part
No C 10/2) will be sufficiently accurate.
This chart is calculated for a barometric pressureof 1013.25mBar which is a figure for a standard
atmosphereat sea level.
However. under extreme weather conditions or at-very high or very low (below sea level) altitudes
the effect of barometric pressurewill become significant.
In order to allow for thesesituations a set of small charts are also supplied that cover the range from
700 mBar to 1100 mBar in 2S mBar steps.
In order to use thesecharts measurethe local barometric pressureand convert ifnecessary to mBar.
Note:
mBar
= 0.001
Bar
= 100 N/m2 = 0.749mm Mercury
The nearest applicable chart should then be used for all calculations under those conditions.
Given any two independentproperties, a state point may be marked on the chart, and from this a
number of properties may be determined. The propertiesrelated by the chart are:
.
(i)
(ii)
(iii)
(iv)
(v)
(vi)
Dry bulb temperature
Wet bulb temperature(sling)
Specific volume
Specific humidity
Specific enthalpy
Percentagesaturation (which may be taken as equal to relative humidity)
It should be noted that the specific enthalpy scale is the enthalpy of the dry air ~ the enthalpy of
the steam associatedwith it (both reckoned from O°C) but expressedin kJ/kg of 5!!Y. air.
Example
Observed Wet bulb temperature = 20.6°C
Observed Dry bulb temperature = 25°C
The state point on the psychrometric chart is located at the intersectionof 25°C Dry bulb and 20.6°C
Wet bulb (sling) - see Figure 10, Page42.
From the chart it will be seen that, at this state, the air has the following properties:
(i)
(ii)
(iii)
and (iv)
Specific volume (v) =
Specific humidity (co) =
Specific enthalpy (h) =
Percentagesaturation =
0.862 m]/kg
0.0135 kgikg
59.3 kJ/kg
67%
The percentagesaturation may be compared with the Relative Humidity calculated from the same
wet and dry bulb conditions of 25°C dry bulb and 20.6°C wet bulb.
From the chart, PercentageSaturation = 67%
By calculation on Page40, Relative Humidity = 67.2%
42
\. ...."...1.. .
..
/
0
I
~.
I
/'
'.
.
.
\
I;
I
0..
..c
.
0-.
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.
~~~
..:
w
..,.
\ \
-0-.\)
1"-..A
..~\
.
.
w
;o.~
,:..:-:!.
-
,---
(")
:J:
>
~
-t
~.j
L:
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..)-.
I,
~
;0
/'"
2
""
III
III
C
2
"'
~
III
'"
0
C
~
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~
2
0
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..
2
n
2
~#
0':-:
.;.
w
~
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..
..
.
..,..~
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-,..
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,..","r-1.1.
.,.jor:';':","";O"~..r-.;
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.,.
c
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o~
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--
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=
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1..
I"""\-;
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('")
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3:
m
-t
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of'"
=
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-e' ~
-
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qq.
"'0
(/)
...
~
I
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-c
.-'
.
.
c
..
.
_w
1ft
w
0
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1ft
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1ft::
n
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)a
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;
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I~~:
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=
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00
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43
CI
,
.~
~
W
Q:
=>
~
[[
"
"I
m
~
\D
W
44
SAMPLE TEST RESULTS AND CALCULATIONS
The following pages give typical observations and derived results from a test with the Air
Conditioning Laboratory Unit.
Note that if the AC660A Computer Linked Upgrade Kit has been fitted. the test results may be
automatically recordedusing the data logging software. The data may then be converted to spread
sheet fonnat and analysedon any suitable spreadsheet package.
;
All, or any of the processesmay be investigated in anyone test provided that the restrictions given
in the RecommendedTest Conditions, Page 30, are heeded.
i
In the following results, all of the facilities are in use and the changesof the properties of the air,
i.e.
and
the wet and dry bulb temperatures
the specific enthalpy
the relative humidity or percentagesaturation
the specific humidity or moisture content
are clearly illustrated and evaluatedby referring to the statepoints and processpaths plotted on the
psychrometric chart.
It should be appreciated that individual units will give slightly different results and that local
atmosphericconditions will have a large effect on the initial condition of the air.
I
In addition, as statedin Useful Data on Page27, the actual output from all heaterswill be influenced
by the supply voltage and this can be calculated using the heater resistance,and the 'local mains
voltage which is given by the panel meter.
The conditions for the following example test results were:
lkW Pre-heating
2kW + IkW Steam Injection
Cooling/Compressoron
Re-heating IkW
Air flow set to a low rate of 3-4mm water gauge
(fthe A660A Digital TemperatureUpgrade Kit hasbeenfitted, then eachof the temperaturesreferred
to on the schematic diagrams may be selectedand displayed on the digital indicator. ;
45
A660 OBSERVATION SHEET
Atmospheric Pressure:
mBar
2
TEST REF.
Dry
I.
°C
23.5
Wet
t1
'C
18.3
Dry
tJ
°C
38.0
Wet
t.
'C
29.2
Dry
t,
DC
25.2
Wet
t,
°C
24.7
Dry
t7
°C
37.0
Wet
t.
'C
27.4
Evaporator Outlet
tlJ
'C
21.5
Condenser Inlet
tJ4
DC
81.0
Condenser Outlet
tis
'C
43.0
Supply Volts: Ll to N (415V)
or LIto L2 (220V)
VL
VAC
225
Evaporator Outlet Pressure
PI
A
B
Air at Fan Inlet
After Pre-heat or
Steam Injection
c
After Cooling/
Dehumidification
n
After Re-heating
Condenser Inlet Pressure
p~
kN m1(g)
290
kN ml(g)
1008
1000
Condenser Outlet Pressure
PJ
kN m1(g)
Duct Differential Pressure
z
mm "10
Fan- -Supply
Voltage
----
Vr
100
Condensate Collected
m.
123
Time Interval
RI34a Mass Flow Rate
3
4
3.9
x
5
600
iii..,
g 5"
14.2
I
4~
I
A660 DERIVED RESULTS
TEST REF.
--
Fan Power
(see
Fan
Volts
v.
Fan
Watts
-
curve)
P,
kW
0.080
p
kW
,180
p
kW
p
kW
1st Pre-heat Power
,,2/R @ 235V
a
2nd Pre-beat Power
V1/R @
C1
Boiler, Lower 2kW Power
V2/R @
Q
Boiler, Upper 1kW Power
Vl/R @ 23SV
a
p
kW
2.254
Boiler, lkW Power
V1/R @ 235V
n
p
kW
ISS
1st Re-heat Power
y2/R @ ...,
n
p
kW
2nd Re-beat Powcr
V1/R @
(}
p
kW
Evaporator Outlet Pressure
PI
kN m1 (abs)
390
Condenser Inlet Pressu~
PI
kN m1 (abs)
1109
Condenser Outlet Pressure
PI
kN m1 (abs)
.101
Evaporator Inlet
tli
'C
8.0
Condensate Rate
m.
kg/sec
0.205
2
3
4
!
47
SPECIMEN CALCULATIONS
From the psychrometric chart on Page 42 the following air properties may be obtained:
I, = 23.3 °C
h"
~ = 18.3 °C
Q)"
= 0.0109kg kg"'
= 38.0 °C
hB
= 94.4 kJ kg"'
t)
51.3 kJ kg-'
= 0.0219 kg kg"
t4 = 29.2 °C
Q)B
ts
= 25.2 °C
~ = 24.7 °C
hc = 75.0kJ kg-'
roc = 0.0195kg kg-
~ = 37.0.C
ho = 86.1 kJ kg".
ta = 27.4 °C
(1)0
Yo
From Steam tables:
ll~
= 0.0190kg kg-I
= 0.905 m) kg"
11
For the ambient air the enthalpy of the water vapour,
h. at atmospheric pressure = 2676 kJ kg-'
Boiler feed water,
hj at 20°C (assumed)
CALCULATION
m
= 84 kJ kg-'
OF AIR MASS FLOW RATE
From Useful Data, Page27.
Air mass flow rate,
APPLICATION
m,
= 0.0517~
~ "0
ria,
.
m,
=
0.0517
~
~~
0.101 k! 'y-l
OF ENERGY AND MASS BALANCES BETWEEN A AND B
Using the Fan Power curve, Figure
power is approximately 80 Watts.
on Page43, at a fan supplyvoltageof 100 Volts, the fan
'I
,
i
The majority of this will result in heating of the air streams via losses in the motor and friction
effects.
For the boiler heatersat 235 VL:
'Ii
:.~
I~
'"
:11
II
Upper 2kW Heater Power =
~
R.
2352
24.S
= 2.254kW
~
lkW Heater Power Rb
2352
47.8
1.155 kW
'itl
il
48
Hence,
.
Boiler Total Po~r InpIlI
2.254
+
1.155
. 3.409
kW
For the 1st IkW Pre-heaterat 235 VL:
-~
Heater Power.
R,
=~
46.8
= 1.lAo kW
'-
..~
Ob
.
3.409 kW
Figure 11
For the system enclosedby the chain line:
By conservation of mass,
m
.
111.«(1).
- (I)..)
. 0.105(0.0219 - 0.0109)
. 1.15 x 10-3 iI ~:I
Applying SFEE,
Heat Transfer Rate Work Transfer Rate
-
Enthalpy ChangeRate
Heat Transfer Rate. Work Transfer Rate:
= Q. + Q, - -PI
= 3.400 + 1.180.. 0.080kW
= 4.669kW
49
Enthalpy Change ~ate:
= m.(h. - h..)
- m. h.
= 0.107(94.4- 51.3) -
= 4.515kW
IS
X 10-3 X 84
This indicates a discrepancy of 154 W.
There is also heat loss from the boiler, from Useful Data,Page27, heat loss rate from boiler =
1.33W/K. Allowing for a temperaturedifferenceof 100 - 23.5= 76.5K,theheatlossfrom the
boiler is 1.33x 76.5 = ~
.
.
Other discrepanciesmay be attributed to inaccuraciesin measurement,the use of the psychrometric
chart and heat loss from the duct.
BOILER
Iheoretical Evaporation Rate
Assumptions:
!
(i)
Steamproduced is saturatedat atmosphericpressureand has a specific enthalpy of 2676 kJ
kg"'.
I
(ii)
The feed water is at 20°C and has a specific enthalpy of 84 kJ kg"'.
(iii)
The rate of heat transfer is 3.125kW 0.102 kW (calculated loss).
-
R
Rate of Evaporation
=
Ah
- 0.102 kg ,,"
3.12S
2676- 84
=
t
1~
._.~
~
x
tn-)
I.U
lrn
&6"
~-1
This may be comparedwith 1.15 x 10.) kg s.\ obtainedfrom the changeof specific humidity between
A and B.
;
.,t~
: ;l:
"~?'
..~t..
c"
:\¥t
REFRIGERATION SYSTEM
The pressuresrecorded from the system are in gauge units relative to atmosphere. In order to
convert these to absolutepressurethe local ambient pressuremust first be added.
The ambient pressurewas
1010
mBar
or 0.757mm Mercury
or 29.8" Mercury
This equatesto 101 kN/m2.
290 + 101 = 390 kN m-t
1008 + 101 = 1109 kn mot
CondenserOutlet = 1000 + 101 = 1101 kN mot
Hence, Evaporator Outlet
CondenserInlet
=
=
II
Ii
,I
Note that a measurablepressuredrop exists in the condenserdue to friction effects. The condenser
is a commercial unit and as such is designedby the manufacturerswith minimum cost as a prime
consideration. The evaporator,however, is purposedesignedfor the A660 unit and utilises oversize
diameter tube to reduce the pressuredrop to a negligible value.
Using the absolutepressuresand temperaturesrecordedaroundthe refrigeration system,a full cycle
diagram may be drawn on a refrigerant Rl34a pressure-enthalpydiagram.
The state points may be detenninedas follows. Refer to Figure 13 on Page51 where the state points
are shown diagrammatically.
Evaporator Outlet/Compressor Inlet (State Point 1)
Locate the 390 kN molhorizontal pressureline and its intersectionwith a superheatedtemperature
of 21.5°C (t,J. The vertical Enthalpy line hi at this point is 314 kJ kg-' and the specific volume is
1.056 mJ kg.l.
Condenser Inlet (State Point 2)
Locate the 1108 kN m-: horizontal pressureline and its intersectionwith a superheatedtemperature
of 81.0°C (tI4). The vertical Enthalpy line hz at this point is 364.4 kJ kg-I.
Condenser Outlet (State Point 3)
Locate the 110 kn mozhorizontal pressureline and its intersectionwith the vertical sub-cooled liquid
line from 43.0 saturatedliquid condition.
It will be found that the point in this case is Q.!!the saturatedliquid line. This indicates that the
liquid is not sub-cooled and reinforces the fact that the condenser is a commercial design. The
Enthalpy h) at this point is 163 kJ kg"l.
After leaving the condenserthe liquid enters the receiver and passesto the expansion valve where
it is assumedto expand adiabatically from 1100 kN m-zto 390 kN mol. Hence a vertical line is
drawn from State point 3 to State Point 4. The 390 kN mo2horizontal pressureline also corresponds
to a line of constanttemperaturebetweenthe saturatedliquid and saturatedvapour conditions at 390
kN mo2. The temperatureof saturation at 390 kN mo2is Soc.
The state points are shown on a real R134a Pressure-EnthalpyDiagram for reference in Figure 14,
Page 52. The conditions may also be determined from the R 134atables provided.
From
the test results the following conditions may be detennined for the refrigeration system:
hi
~,
314.0 kJ kg-.
~
l!
II
l!
. .
I
1
I
: 1
f
!
'I
I
CI
M
m
\D
\D
w
I
OJ
-
+=
:J
0
LOJ
(J)
C
QJ
U
C
0
U
&OJ
(D
C
OJ
U
C
0
U
,
~.
m'1.1
:i:
~
.-
>
~
v
<;~
/'
.
-"'
-OJ
:J
L-
d
L0
0
51
:)
~
~
w
~
rr1
0
~
...
'0
In
~
0
c:
w
>..
a.
0
.c
~
~
~
01
In
~
-
,
Ct:
""
a.
d
...;t
. '1;1
~t)o >
\ W
,c.Q
~ """ ~
0
~
xa.
w
La
(.
-
a.
a
La
d
>
LU
53
vI
-
h
-
0.056 mJ kg.'
364.4 kJ kg-'
161.9 kJ kg-I
14.2 g/s
1
h
=h
=
J
4
m,.,
APPLICATION
=
OF
ENERGY
.
AND
,~
:/
I
he 9'.' kJ kg-1
MASS
---
BALANCES
"
.
BETWEEN
~-
,
-"'.
-
BAND
~
-" "
C-
hC
.
75.0 kJ kg-1
,
I
we . 00219 kg kg-I
~
I
\
J..L.
\
.
~
-1
.
O. ~7
kg
s
..'~
,
..
h1
(
}
J
\
wC . 0.0195 kg kg-1
,
r:tJ
B
\
I
I
I
.
'.."
7
I_b:~
..
"
t
"'
~"C~lEnsote
0123kg 116005
iIe 0.205 x 1)-3
314.0kJ kg"'
v1 . 0056m3kg-1
.
~ . 1619kJ kg-1
Figure IS
From the observedand calculated data, the following parameterscan be stated for the system that
fonns the evaporator of the refrigeration system between Stations B and C of the air conditioning
system,
Calculated rate of condensation from air stream:
= '".(Co). Co)c)
= 0.107(0.0219 - 0.019S)
-
= 0.256 x 10-3 q
.I-I
Observed rate of precipitation
The discrepancy can be attributed to errors of measurementand the use of the psychrometric chart,
to water retention by the fins on the evaporator.and to re-entrainmentof water into the air stream.
Application of the Steady Flow Energy Equation,
Heat transfer rate.
Enthalpy change rate
- Work transfer rate
There is no work transfer rate between Band C, thus
Q,-c
:
(.Thi~ tenn is frequently ignored.)
m.(hc
- h,>
+ m«h; + m,J.h.
- h)
54
m.(hc
- h.>
. 0.107(75
- 94.5)+
+ m.h;
0.205 x 10-3 x 84 kW
= -2.07 kW
m,J-h.
- hJ
=
14.2 x 10-3(314.4- 161.9)
a
2.16 kW
<J.-c
=
<J.-c
= 0.09 kW
-2.07 + 2.16 kW
I
This indicates that there hasbeen a small external heat transfer betweenB and C. as the heat gained
by the refrigerant is slightly higher than the heat given up by the air stream.
Condenser Power Dissipation
The refrigeration systemcondenserservesto reject heat from the systemthat hasbeenextracted from
the air stream, via the evaporatorand the compressionwork input to raise the pressurefrom that of
the evaporator to the condenser.
/
\
,
FO.R.
Application of the Steady Flow Energy Equation,
Heat transfer rate = Enthalpy change rate
-
Work transfer rate
There is no work transfer rate in the above system, hence
Qco.-lISU = tn", (~
= 14.2 X
- ~)
10-3(161.9- 364.4)
= -2.87 kW
Comoressor Power Inout and Coefficient of Performance
!!
the optional AC660A Computer Linked Upgrade is fitted then the compressor current will
be recorded.
This, together with the mains voltage, provides an indication of the compressor electrical power
input.
.
Typically the compressorcurrent under the test conditions, I. = 7.0 Amps.
Hence the compressorreactive power
=
VL x IC
3
=
235 x 7
1645 VA
~
55
Note that the true or active power would be VL Ic x Cos eJ
Where Cas '2} is the power factor.
The power factor is always less than 1.0 for an induction motor and is typically between 0.5 and 0.8
depending upon the quality of the motor.
The coefficient of perfonnance of a Refrigerator
Heat removedat Evaporator Qs-c
Compressorwork W
Based upon the refrigerant enthalpy change acrossthe compressor,
W
- ~)
10-] (314.0- 364.4)
=
dire! (hi
=
=
14.2 X
-0.715 kW (Work into the system)
This compareswith the 1645 VA electrical input.
The difference may be accounted for by power factor (Cas 0). motor
losses and volumetric losses.
r
R heating losses,friction
From the example test results,
Qs-c (basedon refrigerantenthalpy) = 2.16 kW
CoP for a refrigerator based on refrigerant enthalpy changeat the compressor.
- -2.16
0.715
3:.02
CoP for a refrigerator based on electrical input,
2.16
1.645
Ul
It can be seen that the theoretical CoP is much higher than that based on electrical input.
~
Volumetric Efficiencv of Compressor
Volume flow rate at compressor intake,
yI -=
=
.
m,q
VI
/
~r~
lit
0.0142 x 0.056
7.952
x 10-4 m3 .\'-1
'rom Useful Data on Page 27, assumea mean compressorspeedof
2700 + 3<XX> =
.2
t.(
I'X
/),
Compressor swept volume,
2850 rpm at 50Hz.
~~\'i
,r...
!
56
11.
Swept volume
x 10-4
. 7.952
c:c;'~'!"
1.232 X 10-J
=.6ift
III
~
VI I
. _,i'~lf~:
APPLICATION
OF ENERGY BALA~CE BETWEEN C AND D
For the final Re-heaterat 23SV,
Y!
2
Heaterpower Q,
R,
23S2
=
46.4
1.19 kW
hC - 75.0 k. kg,-1
wC a 0.0195
kg
k
hD - 86.1 kJ kg
g.,"
,'
'~:r.'!
t
,
wD
. 0.0190 kg kg
0
C
rho - 0.10 kg s
".I
'1
j'
Or z
1.19kW
Figure 17
Since there has been no increaseor decreasein the moisture content betweenC and D, (J)cand (J)D
should be equal. The small discrepancycan be accountedfor by observation and instrument errors.
Applying the SFEE between C and D,
Q = m(ho - hc>
ma(ho -hc)
= 0.107(86.1
- 75)
= +1.18kW
Discrepanciesbetweenelectrical input and air enthalpychangecalculationswill arise due to
measurement
and instrumenterrors.
I
~
t
57
-
!
t :-
It should be noted that since there is no change in moisture content between C and D, the enthalpy
change of the air may be calculated from,
A.H = m.
Cp(tO4
- tC)
-
m. Cp(T7 T,>
= 0.107 x 1.005[(37 + 273.15)
= 1.26 kW
=
-
(25.2 + 273.15)]
The difference between this and the previously calculated value of 1.18 kW can be accOUnted for by
the factors mentioned above.
m
n
tf
I
I
I
I
I
I
I
58
~o ~.EIERMINE THE SPECIFIC HEAT CAPACITY IC,\ OF AIR
Providedno changeof moisturecontentis involved, the specific heat capacityof air may be
determinedby any convenientsteadyflow process(e.g.heatingor cooling).
Procedure
Having switched on the Air Conditioning Laboratory Unit, the air flow should be set to a convenient
value and the pre-heatersswitched to give 2 kW (nominal) heating.
When conditions have stabilised the following observationsshould be made,
i
TvoicaJ
Dry bulb temperatureat fan inlet
i
i
I
!
Ii
.
t,
20.5 °C
Dry bulb temperatureafter pre-heater t)
45.0 °C
Dry bulb temperatureafter re-heating t7
33.0 .C
Wet bulb tempetatureafter re-heating ta
17.3 °C
Orifice differential pressure
Z
4 mm H2O
Supply Voltage
VL
110 V
Fan Supply Voltage
V,
110 V
1010 mbar
Atmospheric pressure
Typical observationsare given in the following Observation Sheet,
Calculations
Specific volume of air at orifice (from psychrometric chart and t7 and I.)
=
0.876 m) kg-I
Alternatively, since the relative humidity is fairly low (18%), the specific volume may be calculated
from the gas equation,
..
RT
P
~1
=
xJ:}3.0+
273}. m3 kg-I
1.010 x IOS
0.870 m3 k-t
(The discrepancy betweenthe two values is due to ignoring the moisture content of the air.
Using the Fan Power curve, Figure
power is approximately 100 Watts.
on Page 43, at a fan supply voltage of 110 Volts the fan
Air mass flow rate,
:
rI
~"0
0.0517
. 0.0517 rI
kg $-1
~Wj
a
0.110 ia .I-I
Applying the Steady Flow Energy Equation between StationsA and B
Fan Power .. Q,
Iii
= m. (h, - hA)
S9
A660 OBSERVATION SHEET
Atmospheric Pressure.
1010 mBar
TEST REF.
2
Dry
t.
'C
Wet
t2
'C
Dry
t)
'C
Wet
t.
'C
Dry
ts
'C
Wet
I,
'C
Dry
t~
'C
33.0
Wet
t.
'C
17.0
Evaporator Outlet
tu
'C
f:()ndenser Inlet
t,.
'C
Condenser Outlet
tl!
'C
Supply Volts: Ll to N (415V) or
Lito L2 (220V)
VI.
VAC
Evaporator Outlet Pressure
PI
kN
m1(g)
Condenser Inlet Pressure
p,
kN
m1(g)
Condenser Outlet Pressure
P1
kN
mZ(g)
Duct Differential Pressure
z
Fan Supply Voltage
Vt
Condensate Collected
m.
A
B
Air at Fan Inlet
After Pre-heat
or
Steam Injection
c
After Cooling!
Dehumidification
n
After Re-heating
Time Interval
RI34a Mass F1ow Rate
mm H1O
45.0
235
4,0
10
5
iii ~,
20.S
g 5..
3
4
60
As there is no moisture change betweenA and B (there is no steam injection),
. m. C,..(t.~- fA)
=
m. Cp..(t)
-
fa>
C = Fan Power + Q..
P.
m.) (t - t 1)
From the mains voltage V L and the Pre-heaterresistances,
Q = ~
,
#.8
+ .2352
46.4
= 2.39kW -
This compareswith 1.005 kJ kg-' K-' as the acceptedvalue.
This proceduremay alternatively be undertakenacross Station C to Dusing Re-heating.
61
A660 OBSERVATION SHEET
Atmospheric Pressure:
mBar
TEST REF.
J
Dry
t.
'C
Wet
IJ
'C
Dry
tJ
'C
Wet
t.
'C
Dry
t!
'C
Wet
t,
'C
Dry
t,
'C
Wet
t,
'C
Evaporator Outlet
tl)
'C
Condenser Inlet
t'4
'C
Condenser Outlet
t'$
'C
Supply Volts: LI to N (4ISV) or
LIto L2 (220V)
VI.
VAC
Evaporator Outlet Pressure
PI
kN
m2(g)
Condenser Inlet Pressure
PI
kN
ml(g)
Condenser Outlet Pressur~
PJ
kN
m1(g)
Duct Differential Pressure
z
Fan Supply Voltage
Vt
Condensate Collected
m~
A
8
Air at Fan Inlet
After Pre-heat
or
Steam Injection
c
After Cooling!
Dehumidification
D
After Re-heating
Time Interval
RI34a Mass F1ow Rate
I
lit rcl
mm "10
5
g 5-1
1
J
4
62
A660 DERIVED RESULTS
t
TEST REF.
FaD Power
(ste Fan Volts v. Fan Watts curve)
kW
1st Pre-beat Power
V1/R @ 235V
n
p
kW
2nd Pre-heat Power
y1/R @
n
p
kW
p
kW
n
p
kW
y1/R @ 23SV
n
p
kW
1st Re-beat Power
y2/R @
Q
p
kW
2nd Re-beat Power
yz/R @
a
p
kW
Evaporator Outlet Pressure
PI
kN ml (abs)
Condenser Inlet Pressure
p,
kN ml (abs)
Condenser Outlet Pressure
PJ
kN ml (abs)
Evaporator Inlet
I"
Condensate Rate
m.
Boiler, Lower 1kW Power
V1/R
@
Boiler, Upper 2kW Power
V1/R @ 235V
Boiler, lkW Power
1:11
P,
Q
'C
kg/sec
1.
3
4
63
Free Standing Instrument Case housing a Digital Indicator
and 15-way Selector Switch
with attached wet and dry thermocouples
65
OPERATION
There are no special instructions for operation of the A660A Digital TemperatureUpgradeKit once
correctly titted. When power is supplied to the A660 unit the display will automatically illuminate
and display the temperatureselected.
The numbers on the selector switch correspondto the temperaturechannel numberson the schematic
diagram.
Temoerature Indicator
The digital temperature indicator has five function keys on its front fascia. These are used only
during manufactureto configurethe instrument..
Pressing the keys may disturb the displayed value. The displaywill revert to nonnal after a 60
second delay.
The individual temperaturepoints referred to in the schematicdiagram are selected and displayed
on the indicator by switching to the correspondingnumber on the selector switch below the digital
temperature indicator.
MAINTENANCE
In the unlikely event that the digital temperature indicator should fail to illuminate or show
unexpected temperatures,check the following.
.
Failure to IlluDlinate:
Check that the 3-pin UK plug is inserted correctly in the 4-way socket at the rear of the unit.
2.
3.
The digital display operatesat 220/230V on ~ local supplies.
On European voltage (220V L-N) machines the supply is 1 phase and a neutral giving 230V.
On 220V L-L machines the supply is 2 phasesgiving 220V.
The 3-pin UK plugs contain a cartridge fuse in addition to the panel mounted miniature circuit
breakers. Check the continuity of this fuse.
Unexpected Temperatures Displayed:
Check that the correct temperaturesensor is in the correct location. If necessary,remove the
sensor from its expectedlocation and warm it to ensureits responseis correct. If necessaryand
ice and water mix can be used to check the values indicated by all sensors.
Broken thennocouples usually result in an extreme positive or negative display or a fault
indication. If this occurs, the internal thennocouple connections may be checked after first
removing the 3-pin UK plug from its socket or disconnecting the A660 unit from its power
supply.
67
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72
INTRODUCfION
The addition of the A660B Recirculating Duct Upgrade Kit allows investigation of the more usual
practice of recirculating some of the used air from an air conditioning system.
When properly proportioned, this reduces the energy requirements for obtaining the desired
conditions within an enclosure.
However, when incorrectly adjusted, either by negligence or by the desire to reduce running costs
excessively,the result can be a condition sometimesknown as "sick building syndrome".
Recirculatedair can contain dust,micro-organisms,smokeparticles (from cigarettes)and undesirable
smells.
Though the standardair conditioning fittings can remove larger particles. it is not normal for these
to be capable of removing micro-organisms,smells and very small particles. Hence over a period
of time conditions in the building deteriorate to the point where occupants become physically
affected.
The A660B allows the thentlodynamics of the mixing and recirculation process to be investigated
for different recirculation ratios.
A typical recirculating air conditioning system is shown in Figure I
- ~ Fresh
= Air
FIGURE
Here two fans circulate air within the system,one passingair into the systemand another discharging
air from the
system.
The ratio of recirculated air to recirculated air is controlled by a combination of adjustable volume
control dampers and/or the fan speed.
The addition of the recirculating duct to the A660 unit establishesa similar system but using one fan
and one damper.
See Figure
2.
Refer also to the main Schematic Diagram on Page68.
The volumecontrolwhen~
causesall of the air flow to be dischargedfrom the duct.
When the volume control damper is fully open the resistanceto air flow caused by the fresh air
intake orifice causesthe majority of the air flow to be recirculated.
By adjusting the volume control damper to intermediate positions the ratio of recirculated to fresh
air may also be adjusted.
t:9;
,..
:II
73
"
FIGURE 2
DESCRIPTION
Compare the Schematic Diagram for A660 Air Conditioning Laboratory Unit and Upgrade Kits
A660A, A660B, A660C and AC660A on Page 70 with the standard Schematic Diagram for A660
Air Conditioning Laboratory Unit and Upgrades A660A and AC660A on Page 68.
It can be seenthat all of the featuresof the original A660 unit are retained after the addition of the
recirculating ductwork.
The air flow from the fan at top left is still from left to right.
Measuring Station A is still at the fan inlet. This is followed by the stearninjector and 2 x IkW preheaters then measuring Station B.
The evaporator/chiller is between measuring Stations Band C and 2 x lkW Re-heatersare between
measuring Stations C and D.
The discharge orifice from the basic A660 at Station D is removed and replaced by a return bend.
This brings the air flow down to a duct section with measuring Station E and an internal orifice
plate. The orifice plate allows the volume of air passingthrough the fan to be measured.
After the orifice plate is a T section with an exhaustand gravity operated flap valve on discharge.
following the T section is the main volume flow control damper and mixing T.
Fresh air is brought into the system through an orifice plate at measuring Station F. This orifice
plate is retained from the discharge of the basic A660 unit.
By comparing the total flow through the internal orifice plate at Station E and the fresh air at Station
F. the volume of recirculated air may be calculated.
After mixing, the air continues to the fan inlet measuringStation A.
/\11of the functionality of the refrigeration system is also retained and energy balancesacrosseach
component may also be carried out. The experimental procedure with recirculation is identical to
that used for the basic A660 unit and is dealt with in the main manual from Sample Test Resultsand
Calculations onwards.
I
74
The mixing processmay be investigated by the method in the following sections. However, the
orifice plate at measuring Station F is in a "standard" situation in that the coefficient may be
calculatedfrom a standardreference(in this case,ISO TR IS377:1998).
However, the in-duct orifice plate at Station E cannot be precededby the recommendednumber of
effective duct diametersdue to size restraints. Therefore it is necessaryfirst to calibrate the in-duct
orifice at Station E with the orifice plate at measuringStation F.
I,
75
IN-DVcr
ORIFICE
CALIBRATION
--
The in-duct orifice plate at Station E may be calibrated by first fully closing the volume flow control
damper.
Ensure that the reservoirs for the two additional wet bulb stations at E and F (t,. and t12)are filled
before operating the unit.
Level and zero the in-duct and fresh air intake manometersand then turn on the unit., Set the fan
speed at maximum and do not turn on any heaten or the refrigeration system.
Fir the intake orifice,
- 0.0517
rI
~ v,
m,
With the specific volume essentially constant and by conservation of mass, the coefficient for the
air duct orifice may be obtained from,
=
iii.
In -duct
Coefficient
x
For example, the following conditions were recorded
~ -
21.3°C Dry bulb at Station E
tlO = I S.4°C Wet bulb at Station E
tll - 19.6°C Dry bulb at Station F
tIt - 14.9°C Wet bulb at Station F
z. - S.4mm HzO Intake differential pressure(E)
Zp; - S.OmmH2O In-duct differential pressure(F)
(The small differences in temperatureare due to the heating effect of the fan.)
At Station F (the fresh air intake), tll = 19.6°C and tl1 = 14.98C.
From the psychrometric chart,
v£
.
0.84,..3 kg-I
Hence,
lit
= O.~17 f1I
~0:i4
.
At Station
the in-ducl orifice
o.l3.1 kg .r-1
r.= 21 3°C and = 15.4°C.
110
From the psychrometric chart.
v, .
0.84.1 m) kg-I
Hence
iii
.
.
0.131
=
MS3.8 =
In-duct
Co~ffic;~nt
x
~
~o:u;
In -duct Co~fficient
The value for each A660 unit is likely to be slightly different due to manufacturing tolerancesand
local operating conditions.
76
OPERATING PROCEDURE
Pleaserefer to the Schematic Diagram on Page70 (A660 with Recirculating Duct) and the Control
Panel Diagram on Page6.
The operating procedureis identical to that for the basic unit as given in the main manual from Page
28 onwards and including RecommendedTest Conditions.
The only difference is that in order to control the degreeof recirculation the volume control damper
in the lower duct is adjusted.
The volume of fresh air entering the system is shown by the manometerand orifice plate at the fresh
air intake Station F.
The volume of air being passedthrough the air conditioning processesis given by the in-duct orifice
and associatedmanometerat Station E. The difference betweenthe two figures is the amount of air
retirculated.
Wet Bulbs
The recirculating duct has addedtwo wet and dry bulb measuringstations at E and f (t91trOttal and
t.J. As the wet bulb reservoirs are in the lower section of the duct they have individual water
reservoirs which must be filled with demineralisedor distilled water.
~
I~
De2ree or Recirculation
Adjustment of the volume control damper allows the recirculation to be varied from 0 to
approximately 100%. However, the maximum sustainabledegreeof recirculation will dependupon
the local ambient conditions and the amount of stearn or heating that is applied, assuming that the
refrigeration plant is also nmning.
With no refrigeration, the heat put into the system will causethe temperatureto rise until the high
temperaturecut-out operatesat a duct ajr temperatureof 50°C.
Similarly, a high degreeof recirculation together with steam injection can result in a large amount
of water collecting in the lower duct where temperatureswill be lower due to heat losses.
77
SAMPLE TEST RESULTS AND CALCULATIONS
The following pages give typical observations and derived results from a test with the A660 Air
Conditioning Laboratory Unit with the addition of the A660B Recirculating Duct Upgrade Kit. Only
the mixing section is dealt with as the procedures and calculations for the other sections of the
system are identical to those given in the main manual from Page 44.
Note that if the AC660A Computer Linked Upgrade Kit has been fitted, the test results may
be automatically recorded using the data logging software supplied. The data may then be
converted to spreadsheet format and analysed on any suitable spreadsheet package.
It should be appreciated that individual units will give slightly different results and that local
atmospheric conditions will have a large effect on the initial condition of the air.
The conditions for the following example test results were:
IkW Re-heat
I kW Steam Injection
Air flow set to a low rate with moderaterecirculation
~
78
A660 OBSERVATION SHEET
mBar
Atmospheric Pressure:
I
TEST REF.
Dry
t,
'C
21.9
Wet
fa
'C
16.6
Dry
tJ
'C
Wet
t.
'C
Dry
t,
'C
Wet
t,
'C
Dry
t.,
'C
Wet
t.
'C
Dry
t,
'C
30.4
Wet
t'l
'C
21.S
Dry
ill
'C
18.4
tlJ
'C
14.1
Evaporator Outlet
tlJ
'C
Cnndenser (nlet
t'4
'C
Condenser Outlet
t.s
'C
Supply Volts: LI to N (415V)
or LI to L1. (1.1.0V)
VL
VAC
Evaporator Outlet Pressure
PI
kN mJ(g)
Condenser Inlet Pres5ur~
PI
kN mJ(g)
Condenser Outlet Pressure
p>
kN mJ(g)
Fresh Air Intake Differential
Pressure
z,
mm HID
1..5
Duct Differential Pressure
ZE
mm H1O
4
Fan Supply Voltage
v,
VAC
A
B
Air at Fan Inlet
After Pre-heat or
Steam Injection
c
After Cooling!
Dehumidification
D
Arter Re-heating
E
F
Return Air
Fresh Air Intake
Condensate Collected
It
Time Interval
RIJ4a Mass Flow Rate
t
Wet
ffi.
g
I
ritm
g 5".
1
J
4
79
RECIRCULATIONIMIXING
From the test results and the psychrometric chart. at the Fresh Air Intake Station F:
z, ttt
tlJ
V,
W,
h,
=
=
1.5mm H2O
18.4°C Dry bulb
14.loC Wet bulb
0.836 mJ kg.'
0.0082 kg kg"'
39.5 kJ kg-'
~
0.0517
-'
Hence,
iii,
~
)
v,
= 0.OS17r:::i:L
~0:i36
= 0.069kg .I-I
By conservation of mass this equals the air dischargedat the air exit.
At the in-duct orifice Station E:
~ ~ =
tit VE =
WE=
hE -
4.lmm H2O
30.4°C Dry bulb
21.5°C Wet bulb
0.876 m' kg-.
0.0124 kg kg-.
62.5 kJ kg-'
The air passing through the fan in A also passesthrough Station E.
mA
:
O.OS38
~
~~
from the earlier In-duct Orifice Calibration, Page 75.
Note that the value obtained for the unit in use should be used.
iii
A
~
~o:m
= O.OS38
.
O.1163q.r-l
80
From Figure 3 and by conservationof mass, the air flow recirculated back to the mixing section
- m-m
A ,
= 0.1163- 0.069
mA- m, = 0.0474kg $-1
Assuming no heat loss or gain from the mixing section (adiabatic flow) and applying the Steady
Flow Energy Equation:
.
hA
Substituting for the known values:
hA
5.688
01163
~
kJ kg-I
By mass balance,
iii.. w..
~
mF WF + (mA - mF) WE
m, w, + (mA - mF) WE
w..
iii..
Substituting for the known values,
WA
.
= 0.JX)22kg kg-I
Using the intersectionofh,. = 46.5 kJ kg". and w,. = 0.0099 kg kg-I, the State Point A may be plotted
(Refer to Page42 PsychrometricChart) and comparedwith the observedvalue from t. and ~"
the differences can be attributed to measurementerrors and heat loss/gain from the surroundings.
Note that from the Steady Flow Energy Equation and conservationof mass,
m.. h.. = mF hF + (m.. - mF) hE
mA
It can be shown that,
m~-
(mA- m,)
= m, + (mA- m,)
~~
hA- h,.
This is the ratio of
From the mass flows
0.069
0.0474
1.4SS:1
A:
,.
Oll
~II
~
011
,.
001
0.
01
i'
..
~'"
-
° .. . .. . .. , ,., to (IIY
Ala)
0
0 0 °
0000000000000
.,. r
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~
.-+
5./8~
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°
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':~'~~I"::'~'
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83
Ic',::
,.
.
IT
85
INTRODUCTION
The data logging software supplied with the AC660A Upgrade is an interim measure. Windows
software will be supplied without further charge when available.
The software provided is a fully operational copy of P.A. Hilton's HEAT97 data logging software
with pre-configured tiles that relate to the transducerchannelsin use on the A660 unit.
If the AC660A Computer Linked Upgrade Kit was factory fitted by P.A. Hilton Ltd. the
configuration files on the disc supplied will be pre-calibrated to match the transducers on the
particular machine.
If the AC660A was user fitted, the calibration is carried out s part of the AC660B Software Upgrade
installation carried out by the user.
The GETTING STARTED section of the AC660B Software Upgrade manual deals with initial
operation of the data logging software.
The pre-configured files for use with the factory fined AC660A are:
Channel config.fiIe
Conversion Factors file
Output file
)
66OCHAN
660CON
6600UT
The first screen displayed when starting the HEA1'97 software shows the file names of the.
configuration files in use.
The file namescan be changed by moving the highlight bar to the line required then pressingEnter.
The flashing cursor will indicate that text can be changed. Then pressing Enter again will confinn .
the change.
Changescan be made repeatedly in the case of errors.
Note that if a filename is entered for which there is no pre-configured file, a new file will be created.
However, each parameterfor the system will have to be specified.
I
I
I
I
Use of the above pre-configured files will ensurenonnal operation until familiarity with the software
has been gained.
It is recommendedthat the DLS Data Logging SystemSoftware User Guide. DLS/SOFT Issue .01,
Ref. August 97 is read in order to expand on the capabilities of the data logging software.
For reference.the Hilton Data Logger and Controller Connections,Specificationsand Instrumentation
Set Guide is also supplied. This gives details of hardwareconnectionsto the data logger and ASCII
serial commands for studentswishing to write software to accessdata directly from the data logger.
~
Free Standing Instrument Case housing a Digital Indicator
and 15-way Selector Switch
with attached wet and dry thermocouples
~
,
Al
A660A DIGITAL TEMPERATURE
UPGRADE KIT
FITTING INSTRUCTIONS
SUITABLE FOR:
A660 Air Conditioning Laboratory Unit
WITH OR WITHOUT:
A660B Recirculating Duct Upgrade Kit
OR:
A660C prD Control Upgrade Kit
SKILLS REOUIRED:
I.
This upgrade is well within the capabilities usually found in a Laboratory Technician or similar
tradesman. Only fitting of pre-wired thennocouples into the duct is involved.
The A660A Digital Temperature Upgrade Kit is built and shipped on a transit rack to obviate
tangles. The rack is hung on the rear of the evaporator. Each thermocoupleis unwound in turn
and titted in place of a spirit thermometer.
I
The power supply cable is simply plugged into a built in 4-gang socket outlet on the A660.
One person can perform this upgrade. Expect the job to take less than two hours.
No special safety considerations apply, with the exception of discoMection of electrical and
water supplies in some cases,to gain accessto the rear of the unit.
Operation of the A660 is unaffected. Temperature data is conveniently gathered at a centJal
point.
STANDARD PARTS SUPPLIED:
-~--
Q1Y
,
6
3
6
;
DESCRIPTION
Transit Rack, containing:
Instrument Case with indicator and I S-way selector switch
Dry Bulb, Type K Duplex Thennocouple, I SOmmacrylic
Dry Bulb, Type K Duplex Thennocouple, IOOmmcopper
Dry Bulb, Type K Duplex Thennocouple, 300mm acrylic
Power Supply Cable (attached)
PREPARATION:
Examine the packing case and infonn the shipping insurers immediately if damaged.
;'
,
2
Unpack and check ofT the contents against the Packing List. Note that the above list is for
guidanceonly. The Packing List supplied in the product envelopeis fully detailed and accurate.
),
Isolate the electric and water suppliesto the A660. Disconnectthem, if movementon the castor
wheels is necessaryto gain accessto the rear of the unit. Movement may strain or fracture the
supply lines.
4.
Remove and retain the existing wet/dry spirit thennometers Store them as a back-up system.
.
I
Note that T9 to TI2 are only used when the A660B Recirculating Duct Upgrade Kit is
il.l~
: Ii
I,.
'_l!
A2
fitted. Also note that the flyin2 leads stowed in terminal blocks are only used when the
AC660A Comouter Linked Uo2rade Kit is fitted.
u
Iii
Ilj
)\
i'.ll1
fill
tt~
1 "\:I;,
1\
; I:
A3
INST A LLA TION:
Carry the assembly to the rear of the A660 unit.
2.
Unhook the elastic strap and releasethe instrument casefrom its transit position. Use one hand
to hold the case and the other to hold the rack to avoid straining the umbilical cables.
3
that it hangsdown behindthe evaporator.
Place the instrument case on top of the evaporator and engagethe hooked edge of the rack so
.
4.
Rotate the tilting legs beneaththe caseand place on top of the evaporator.
s.
Unwind the wet/dry thennocouplesin turn and tit them into their duct locations or thennometer
pockets as applicable. The schematicdial!rams show the correct Dositionsfor TI to TIS.
6. Ensure the wet bulb locates inside the in-duct reservoir by entering centrally and at 90° to the
duct.
7.
Use the self-adhesive nylon clips to tidy the routing of the wires. Excess length may be left
coiled on the rack.
8. Uncoil the power supply cable and plug into the 4-gang socket outlet.
9.
Ensure the wet bulb distilled water reservoir is filled to the Max level mark.
10. Restore power and water supplies and switch on the main switch. The digital temperature
indicator will perform a self-test, then display the temperatureof the selectedchannel.
The push buttons on the face of the indicator were used to pre-configure the instrument to read
Type K thennocouples. They are not assignedto perfonn any function during nonnal use.
Pressing the buttons may disturb the display, but the measuredvalue will return after a short
pause.
12. Select each channel in turn to verify correct operation. Each dry bulb will indicate the duct air
temperature. The wet bulb temperaturedepressionwill be a function of RH% and dry bulb
temperature.
\,r
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l
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84
A660B RECIRCULATING
INSTALLATION
DUCT UPGRADE KIT
INSTRUCTIONS
SUITABLE FOR:
WITH OR WlmOUT:
A660 Air ConditioningLaboratoryUnit
A660A Digital TemperatureUpgrade Kit
AC660A Computer Linked Upgrade Kit
SKILLS REOUIRED:
This upgradeis well within the capabilitiesIJsualJyfound in a Laboratory Technicianor similar
tradesman. Only titting of and tightening of fasteningsis involved.
One person can perfonn this upgrade, but two arc preferred when manoeuvring long duct
sections. Expect the job to take less than half a working day.
No special safety considerationsapply, with the exception of disconnectionof electrical and
water supplies in some cases.
Where this upgrade is perfonned on a computer linked A660, a second differential pressure
transducermust be coMected to the data logger. The ability to follow a wiring diagram would
apply in this case. Follow instructions in Appendix C: Computer Linked Upgrade.
STANDARD PARTS SUPPLIED:
PART No.
A660B/I/I
A660B/I/2
A660B/1/3
A660B/I/4
A660/6/4
A660B/4/2
A660B/4/4
A660B/4/5
A660B/4/6
A660/3/4
A574/37/1
RMX58/1
IMI2/8
IM3/2
C20/24
RMX57/1
C13/41
IMI6i'1
SFI/54
SFI/28
SFI/41
SFI/t02
SF3/2
SFI/55
SF4/4
RMX29/1
SF20/1
QTY DESCRIPTION
1 Air Duct 180° Return Elbow
1 Air Exhaust Tee
I
Air Inlet 90° Elbow
1 Air Volume Control and Mixing Tee (trolley mounted)
I
A3 Schematic Diagram
2
Duct Support Strap
1 Support Frame, Front
I
Support Frame, Rear
I
Castor Wheel SupportAngle
I
Duct Support Angle
4
Rubber Gasket, Duct Flange
3
End Caps to blank manometer
3
Wet Bulb Spirit in GlassThermometer,0 to SO°C
3
300mm Spirit in GlassThennometer,0 to sooC
3
Rubber Stopper,25mm dia.
I
Duct Tape, 50mm wide
I
SqueezeDispenser,230ml
I
Inclined Manometer,0 to 12.5mm WG
2
M8 SS Washer
2
M8 x 20 Hex Head Screw
10 M6 x 20 Hex Head Screw
48 M6 x 30 Hex Head Screw
96 M6 Nylon Washer
116 M6 Plain Washer
58 M6 Nylock Nut
JOOcm6mm bore Clear PVC Manometer Hose
4
M6 Plastic Fluted Nut
B5
A660B/5/2
Tool Kit (ratchet handle, IOmm/13mm tools)
PREPARATION:
2.
Ensure the area around the A660 Air Conditioning
the completed recirculating duct.
Laboratory Unit is large enough to accept
Dimensions:
Hei~60 mm
Length 3630 mm
Depth 530 mm
3.
A pre~assembledlength of duct will be passed,from the fan end, under the existing duct.
Total
length of floor space required during assemblyis 6.6m.
4.
Unpack and check off the contents against the Packing List. Note that the Standard Parts
Supplied list is for guidance only. The Packing List supplied in the product envelope is fully
detailed and accurate.
5.
Isolate the electric and water suppliesto the A660. Disconnectthem if movement on the castor
wheels will strain or fracture the supply lines.
6.
7.
8.
Remove and retain the wet/dry thermometers(T: and 1'2) at the intake to the fan.
Disconnect
the 12 water
reservoir
and drain
into a receptacle,
or tie the hose up to prevent
damage.
9. Remove and discard the fan finger guard by unscrewing the duct clamp.
EXTENDED FRAME SUB-ASSEMBL X
Comprising:
PART No.
A660B/4/4
A660B/4/5
A660B/4/6
A660/3/4
SF1/41
SFI/55
SF4/4
SF20/1
QTY
I
I
I
I
10
20
10
4
DESCRIPTION
Support Frame,Front
Support Frame, Rear
Castor Wheel Support Angle
Duct Support Angle
M6 x 20 Hex Head Screw
M6 Plain Washer
M6 Nylock Nut
M6 Plastic Fluted Nut
10. Assemblethe three-sidedC-shapedframe to the right-hand end of the main frame. (See Figure
I for correct positioning of the lower cross bar and castor wheels.) Do not fully tighten the
attachmentscrews until they are all fitted.
Fit the duct support angle shown in detail A of Figure
to the plastic duct flange first using 2
86
plastic M6 thrum nuts as temporary fixings. Then use the remaining 2 plastic thumb nuts to
secure the duct support angle to the newly fitted front and rear frames.
12. The castorwheel is fitted with jacking pads. Screwthesefully down, they may be adjustedafter
passing the lower return duct assemblythrough the frame.
I
=1
I
l
-- I
m
m
~
~
w
B7
rT1
0"
0"
m
m
B8
IN
--
EXIT ORIFICE
PLATE
SHIPPED SUB-ASSEMBLIES
180. RETURN
ELBOWS
~
VOLUME CONTROL. MIXING TEE
AND FRESH AIR INLET {TROLLEY
HOUNTED)
RETURN DUCT. WITH FLOW ORIFICE
AND EXHAUST TEE
FIGURE
-=
89
LOWER RETURN DUCT ASSEMBLY
-
-
-
Comprising:
PART No.
A660B/I/2
A660B/I/4
A660B/4/2
A574/37/l
SF1/54
SFI/28
SFl/IO2
SF3/2
SFI/55
SF4/4
SF20/1
QTY
I
I
2
I
2
2
12
24
24
12
4
DESCRIPTION
Return Duct with Flow Orifice and Exhaust Tee
Air Volume Control and Mixing Tee (trolley mounted)
Duct Support Strap
Rubber Gasket,Duct Flange
M8 SS Washer
M8 x 20 Hex Head Screw
M6 x 30 Hex Head Scre.w
M6 Nylon Washer
M6 Plain Washer
M6 Nylock Nut
M6 Plastic Fluted Nut
13. Connect the two horizontal duct sections (refer to Figure 2 to identify the duct work
components)together on the floor to make the complete lower run of duct. Refer to Figure 3.
14. Refer to diagram for correct assemblyand note:
. Use a steel washer and nylon washerunderthe headof each hex bolt and each nut. Do not
over tighten.
Use a rubber gasket betweeneach flange.
. Exhaustgrille faces front, duct window is on top and thennometer reservoir faces towards
the operator.
The volume control handle facestowards the operator.
.
.
15. The exit orifice plate (removed at Step6 above)may now be fitted as the fresh air intake orifice.
Refer to Figure 2.
16. Remove the TIO internal wet bulb reservoir from the bottom of the duct to avoid damage.
Rotate the external reservoir to a horizontal position. This will be refitted later.
17. The duct sectionsare now ready for installation. Preparethe frame to acceptthe duct by laying
the two flat strips provided on top of the lower main frame. Theseprovide a flat surface for the
duct flange to slide along without damage.
18. Located betweenthe castor wheels,below the fan, there are two M8 captive nuts. These re the
anchor points for the trolley. Screw in two M8 x 20mm Hex bolts with large M8 washers,from
below. Enter by three threadsonly, final tightening will be done after docking the trolley.
Comprising:
PART No.
SF1/54
SFI/28
INSTALLATION
QTY DESCRIPTION
2
M8 SS Washer
2
M8 x 20 Hex Head Screw
OF PRE-ASSEMBLED DUCT
19. The assistanceof a second person is advised.
20. Position the pre-assembledduct in line with the existing duct at the fan end. Lift the return duct
to rest the flange on the support straps.
-
B10
21. Push the duct through until the slots in the trolley engagewith the M8 anchor bolts. Do not
tighten the M8 anchor bolts at this stage.
I
!
.
812
VERTICAL DUcrs
Comprising.
PART No.
A660B/I/2
A660B/I/3
A574/37/1
RMX57/1
SFI/I02
SF3/2
SFt/55
SF4i4
QTY
I
I
3
I
36
72
72
36
DESCRIPTION
Return Duct with Flow Orifice and ExhaustTee
Air Inlet 90° Elbow
Rubber Gasket, Duct Flange
Duct Tape, sOmmwide
M6 x 30 Hex Head Screw
M6 Nylon Washer
M6 Plain Washer
M6 Nylock Nut
Refer to Figure 2 to identify the ductwork components.
22. Connect the 90° duct betweenmixing tee and fan inlet. Usethe duct tape to hold the alignment
of the cin:ular stub with the fan intake, then fit the fast clamp.
I
23. The TIO internal reservoir was removed at Step 16 above. Refit and reconnectto the external
reservoir. Referto Figure4.
24. CoMect the 1800double elbow to complete the circuit to the return duct. Refer to Figure S
25. Once all componentshave been coupled together,tighten the flange bolts, frame bolts (replace
any plastic thumb nuts with the stainlesssteel locking nuts provided). Finally tighten the t"wo
M8 bolts securing the lower return duct assembly.
.
MANOMETERS
Comprising:
PART No
RMXS8/ I
IMl6l1
QTY DESCRIPTION
3
End Caps to blank.manometer
1 Inclined Manometer, 0 to 12.5mm WG
26. Fit the new inclined manometerat the fresh air intake and adjust until the spirit level bubble is
central.
.
27. After levelling, the transit caps should be removed from both ports before zeroing the scale by
use of the knurled adjusting nut. (Ensure the mm ~O scale is fitted.)
28. Connectthe hose betweenfresh air intake duct tapping and the manometerright-hand port. The
left-hand port remains open to atmosphere.
29. The other inclined manometermust be removed from the upper duct and relocatedon the lower
return duct. Disconnectthe manometertube and fit end caps to both ports to prevent spilla'ge
of manometerfluid. Transfer to the new location on the return duct.
30. Level and zero as for the fresh air manometer,but connectthe hoseseither side of the in-duct
orifice in accordancewilh the schematicdiagram, Page82.
r'1
0'
0'
~
m
I~
A660
CROSS SECTION OF DUCT THROUGH WET BULB RESERVOIR
t6
\i
woe
T W LB n£JIO£TER
PART~ 1H12/8
DRY Bll8 T~~
HOT SHO'w'N~
(LARTY
CENTRAL
~Al
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~
--==:=tI-~=
10,~
~"
NTE~.A.l
fESERWR
p
~
.0.
~p
RESERVOO UN<N3 TUBE TO
LPS1f£AH AN) OOWSTREN1 f)XTS
-~'
~
TOt
'-- -~
TO
4 WETBl1.B RESERVO~
B '¥E.T B..I..B FE SE ~
Ri~E4
~
H13
f'T1
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0'
m
ED
814
IU)
81~
~zi
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-I~
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11
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-=
HIS
THERMOMETERS
Note that if the A660A Digital TemperatureUpgradeKit has beenpurchased,the thennometerswill
be ultimately replaced by the thermocouplesensors.
Comprising:
PART No
1M12/8
1M3/2
C20/24
CIJ/48
QTY
3
3
3
I
DESCRIPTION
Wet Bulb Spirit in Glass Thennometer, 0 to 50°C
300mm Spirit in Glass Thennometer, 0 to 50°C
Rubber Stopper,25mm dia.
SqueezeDispenser,230m.
Refer to schematicdiagram on Page'82 for the location of the temperaturemeasuring points
31. Connect the new T2 internal wet bulb reservoir to the main reservoir systemand replenish with
distilled water.
32. Fill the new external reservoi~ located at TIO and Tl2.
33. Fit T
1'2, 1'9, TIO, TII and Tl2 wet and dry thermometers.
FUNCTIONAL TEST
34. Restorepower and water supplies and switch on the main switch. Run the following functional
test with air heatersand compressoroff.
35. Open the volume control device and verify that 1000/.recirculation can be achieved. The
exhaust gravity grille should close automatically and the inclined manometerat the fresh air
intake should be reading approximately zero (denoting no incoming fresh air).
36. Adjust the fan speed conh"ol to vary the air now velocity through the duct. The total orifice
differential pressurecan be set to any value betweenminimum flow (3mm H2O)and maximum
indicated now (12.5mm H2O) Water Gauge. The maximum value achieved will dependupon
the local mains supply voltage.
37. Shut the volume control and check that the exhaustgrille opens automatically. Both inclined
manometersshould read approximately the samevalue, indicating that all incoming fresh air is
passingthrough the exhaust. There may be a discrepancybetweenthe two readingsat identical
mass flow. The in-duct orifice may be calibrated from the intake orifice when the specific
volume of the air (m)/kg) is the same,i.e. TII = 1"9. A calibration constantmay be calculated
and this is dealt with in the supplementto the main manual.
38. The maximum flow will decreaseto lessthan full range of the manometer,possibly 9mm H2O.
This is due to reduced pressureat the fan intake. Air at atmospheric pressureis now being
drawn into the fan, but during the recirculation test air was being pushedinto the fan. The flow
is further restricted by the work done to open the exhaustgravity grille and to force the flow
through the two orifice plates.
39. Vary the position of the volume control to achievea visual representationof 50% recirculation,
such as intake orifice = 2mm, total orifice = 4mm. Try 75% recirculation at, say, intake = 3mm,
total flow = 12mm. (3/12 x 100/1 = 25% fresh)
40. The unit is now ready to perform the experimentslisted in the main manuaJunder the heading
.,Additional Experiments with A660B Recirculating Duct Upgrade".
c
Must be preceded by, or concurrent with
A660A Digital Temperature Upgrade Kit
Cl
AC"OA COMPUTER LINKED UPGRADE KIT
INSTALLATION
- WtlEN
RECEIVED WITH FACTORY FITTED AC660A
Yau have turned to this APPENDIX C in compliance with the Installation instructions contained in
the main manual. They are restatedhere.
ORDER OF INSTALLATION
WHEN RECEIVED WITH OPTIONAL UPGRADES:
On completion of the factory fitted computer linked upgrade, the Duct Differential Pressure
Transducerwas disconnectedfor transit. The signal cable (labelled Channel20) remains connected
at the Data Logger end and is coiled and tied to the frame.
The logger power supply cable may have been unplugged during packing.
They must be reconnected to complete the installation on site. The A660A Digital Temperature
Upgrade is obligatory in accordancewith Appendix A of this manual, as is the AC660B Software
Upgrade.
Where this upgrade is perfOrD1edon an A660 with A660B Recirculating Duct Upgrade, both
differential pressuretransducers (Channels 20 and 21) must be connectedto the data logger and
thermocouplechannels 1'9, TIO, Til and T12 utilised.
Where this upgrade is perfonned on an A660 with A66OC PID Control Upgrade,the PID Controllers
and the data logger may share the output from the duct RH% (Channel 22) and duct temperature
(Channel 23) transducers.
STANDARD PARTS SUPPLIED:
PART No.
1M20/5
ES/4
ESnB
E5/133
SFI4/1
E45/4
C7/3
C13/44
SF2S;2
C 19/6
RMX29/1
QTY DESCRIPTION
2
Differential PressureTransducer,0 to 25.4mm H10 WG (one fitted)
2
IJA Plug
3
JA Cartridge Fuse
1 4-gang Extension Lead
4
Self Tap x 9.5 Diff PX
1
External Serial Lead, 25F
25 Cable Tie
20 Cable Tie. long
5
Cable Tie and Base
10 Self Adhesive Cable Clip
300cm 6mm bore Clear PVC Manometer Hose
C2
C48/2
AC660B
£43/3
3
6mm Plastic Tee for manometerhose
Computer Linked Upgrade Software
2mm Hex Saewdriver for Logger
25M to 9F Serial Converter
Wiring Diagram, Logger to Transducers,Drg No 66OC04M
PROCEDURE:
Isolate A660 unit from power and water supplies,
2
Plug the logger power supply cable into the 4-gang socket outlet.
3
Connect the external serial lead by plugging' into the 'socketat the Status/Samplelamps
4
The second4-gang extension lead is provided for use by a computer, monitor or printer, able
to use the 220-240V AC available from the A660 socket outlet. This may be at 50 or 60 Hz.
Unclip the coiled "Channel 20" cable attachedto the rear of the frame.
6.
Route the cable to the downstreamduct differential pressuretransducer. Use self-adhesiveclips
on the dud and cable ties to the frame to keep it tidy.
7. Connect the cablesto the transducerterminals specified on the wiring diagram No 66OC04M.
A660B only - Fit the spare transducer to the recirculating duct abo~ the inclined
manometer. Pre-drilled fIXing holes exist in the ductfor this purpose.
Connect the manometerhoses by teeing into the existing i1k."linedmanometerhoses. The
SchematicDiagram may be usedas a guide.
Unclip the coiled "Channel 21" cable attached to the rear of theframe and connect.
8. All channels are now connectedwith the exception of the temperaturechannels. Install the
A660A Digital TemperatureUpgrade Kit in accordancewith Appendix A of this manual, but
return to this section before doing a functional test.
The leadsstowed in the tenninal blocks plug into the correspondingsocketson the data logger.
Note that the coloured numberson the thermocouplewires relate to the channelnumberson the
data logger tenninal label. Hence I (Brown or Green) is Channel 01+, 01-, terminals 02,04.
The plugs are pre-wired in order and all that is required is to check the correct location of one
channel on each block of 8. Refer to Figure 1 below.
T(J=
~
~
C3
FUNCTION TEST:
---
9.
Restorethe water and electrical supplies.
10. Switch on the main switch, the fan will run and the digital temperatureindicator will illuminate.
II. Observethe Data Logger at the moment of switching on. The Sample/FaultLED should flash
a few times as it perfonns a self-test, then go out. This LED will come on each time a logging
sampleis taken when the computer is connected. The Power LED will glow continuously when
power is supplied.
12. If satisfactory, continue with loading software and proving all channels. SeeAppendix D.
r
C4
AC660A COMPUTER LINKED UPGRADE
DISCLAIMER
The upgradeproceduresoutlined in the following manual may, at additional cost, be carried out by
Hilton personnelat our factory in the UK. If this option is chosenthen the normal Hilton parts and
labour warranty will be applied to the modification.
If the above option is not chosen and the upgrade is carried out by the customer or non-Hilton
personnel,then P.A. Hilton lid disclaim all responsibility for accidents,damageor injury resulting
from or during the upgrade procedureand/or by operation of the upgradedmachine.
AC660A COMPUTER LINKED UPGRADE KIT
-USER INSTALLED
C5
SUITABLE FOR:
A660 Air Conditioning Laboratory Unit
WITH OR WITHOUT:
A660B Recirculating Duct Upgrade Kit
A660C PID Control Upgrade Kit
MUST BE PRECEDED
BY OR CONCURRENT
WITH:
A660A Digital TemperatureUpgrade Kit
NOTE: Customers who have purchasedA660A Digital Temperature Upgrade Kit and AC660A
Computer Linked Upgrade Kit together should install the AC660A kit first followed by
A660A, in accordancewith ApP.endixA of this manual.
SKILLS
REOUIRED:
WARNING:
Local regulations may prohibit unqualified personnel from undertaking any
form of refrigeration work.
WARNING:
Pressurised refrigerant within the systemcould escapeif fitting instructions are
not followed exactly. Refrigerant gas or liquid under pressure can damage
eyes, cause frost damage to skin, and suffocation if inhaled to the exclusion of
oxygen. Compliance with the procedures listed below will reduce these risks.
This upgrade is well within the capabilities usually found in a Refrigeration Technician,
Electrician or Electronics Technician. Operatives must have the ability to read a wiring diagram
and make safe electrical connections.
Minimal computing skills are required, full instructions ar:eincluded in this Appendix,
One person can perform this upgrade. Expect the job to take one working day.
Where this upgrade is perfonned on an A660 with A660B Recirculating Duct Upgrade, both
differential pressure transducers (Channels 20 and 21) must be connected to the data logger and
thennocouple channels 1"9, TIO, TII and Tl2 utilised. As it is possible at any time to purchase
and fit the A660B Recirculating Duct Upgrade Kit it is recommended that BOTH the differential
pressure transducers are connected to the data logger so that both can be calibrated for future
use.
Where this upgrade is perfonned on an A660 with A66OC PID Control Upgrade, the PID
Controllers and the data logger may share the output from the duct RH% (Channel 22) and
Temperature(Channel 23) transducers.
C6
AC660A COMPUTER LINKED UPGRADE KIT
CHANNELS USED
LOCATION
.widl recirculating duct models
twidl PID control models
CHANNEL
Numb«r
SYMBOL
UNITS
A Fan Inlet Air (Dry)
TI (AJ
-c
z
A Fan Inlet (Wet)
n(A.)
~
J
B After Steam/Prebeat (Dry)
TJ (8,)
4
B After Steam/Preheat (Wet)
T4 (8.)
-c
-c
s
C After Cooling/Dchumidification
(Dry)
TS (C,)
8(:
6
C Alter Cooling/Dehumidification
(Wet)
T6 (C.)
-c
1
0 After Reheat -+ to Room (Dry)
1"7(0,)
~
.
0 After Reheat-.. to Room (Wet)
TI (0.)
-c
9
E Rettlrn from Room (DIy)-
T9(E,)
-c
10
E RebJrn from Room (Wet)-
TIO (E.)
~
II
F Fresh Air Intake (Dry).
TII (F,)
~
TI2 (F.)
-c
--
12
F fresh Air Intake (Wet)-
I.J
Evaporator
14
TI3
~
Condenser Inlet Temperature
T14
~
IS
Condenser Outlet Temperature
TIS
~
16
Supply
v
VAt
11
Evaporator
---
~
88(&)
I'
CondenserInlet Pressure
P.
B8(g)
19
Condenser Oudete Pressure
P.
8-<1>
20
Duct Differential
y
111mH1O
21
Fresh Air Intake DifferentiaJ Pressure-
.
mmWO
22
Return Aw RH-I.t
2J
Return Air Temperaturet Set Value OC
24
Fan Power (see Fan Volts Ys. Fan Watts curve)
25
1st Rc-hcat Power VIR @
26
2nd Rc-heat Power VIR @
27
RI34a Flow Rate
Outlet
Volts
- LI
Outlet
.
Temperatule
---
to N or LI
to L2 (Hot)
.
Pressu~
Pressure
-loR}{
Set
Set Value
Value %
0/.
.-
Q
P,
P
a
p
~
w
w
w
g/SCC
M,.
28
Boiler Lower 2kW Power V~
@
.Q
p
29
Boiler Upper 2kW Power V~
@
Q
p
w
30
Boiler IkW Power VIR @
{}
p
w
31
1st PreheatPower VIR @
a
p
w
32
2nd PrdICat Power VIR @
»
C~ressor
..'.
-.
n
,
w
A
Current
OUTPUT
~plc
OUTPUT 2
SIaIUSLamp
lamp
W
On/OtT
On/OtT
C7
STANDARD PARTS SUPPLIED:
Figure 2
or Figure 3
Figure 4
I
Wiring Diagram, Connection to Switch Panel (4l5V) Drg No 66OCO5M
Wiring Diagram, Connectionto Switch Panel (220V) Drg No 66OCO7M
Wiring Diagram, Logger to TransducersDrg No 66OC04M
PART No.
QTY DESCRIPTION
AC660/6/1
1
Refrigerant Flowmeter ft2, 0.05 to 1.6 Vmin
AC660B
1 Computer Linked UpgradeSoftware
PFI/34
1 3/8 Flare Copper Gasket
E3/124
I
Flowmeter Lead
I
Pre-wired DIN Rail Assembly (CT & Volts)
AC660/5/1
SF4/3
2
M5 Nylock Nut
16 M5 SS Washer
SFI/47
SF3/1
12 M5 Nylon Washer
SFl/18
16 M5 x 12 Hex Head Screw
AC660/2/1
I
Heater Relay PCB
3
PressureTransducer,-I to +15 Bar (gauge)
IM49/2
CIJ/56
3
P Clip for pressuretransducer
C6I14
3
Capillary Tube with depressor
3
M8 x 25 Hex Head Screw
SF1/29
SF1/54
3
M8 Washer, 19 o.d.
1
Data Logger with Hex key
DLS/l/l
1
RS232 Socket. Statusand Sample Lamps
HC655/5/1
2
Data Logger Mounting Plate
AC660/1/1
1 Data Logger Power Supply Cable, 13A plug
E3/249
4
Self Tap x 20 Logger
SFI/118
C7/J
25 Cable Tie
CIJ/44
20 Cable Tie, long
SF25/2
5
Cable Tie and Base
10 Self Adhesive Cable Clip
C19/6
RMX15/5
6cm 1/4" Nylon Tube
RMX29/1
300cm 6mm bore Clear PVC Manometer Hose
C48/2
3
6mm Plastic Tee for manometerhose
E2/22
6
Crimp Terminal, 3.5mm fork
E4/16
2
3 core, 0.5mm Cable, 4m long
1M20/5
2
Differential PressureTransducer,0 to 25.4mm H2Q WG
E5/4
2
13A Plug
E3nS
3
3A Cartridge Fuse
E5/133
I
4-gang Extension Lead
4
Self Tap x 9.5 Diff PX
SFI4/1
E45/4
I
External Serial Lead, 25F
C20/28
2
Grommet for 30mm hole
E43/3
125M
to 9F Serial Converter
-
Small scale copies of the larger colour drawings supplied are contained in Figures 2, 3 and 4 for
identification purposes.
Ensurethat the correct mains wiring diagram is referredto, e.g. 415V or 220V as appropriateto the
unit ordered and the local supply.
-rl
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STANDARD TOOLS SUPPLIED:
A660/10/1
1
IO/llmm Open Jaw Spanner
C4S/3
1 CompressorCharging Valve Key
C4S/2
I
Refrigerant Charging Line
C13/63
I
4mm Flat Blade Insulated Screwdriver
CI3/62
I
3.2mm Flat Blade Logger Terminals Screwdriver
B500/10/3
1 No.2 Pozidrive Screwdriver
AC660/3/1
2
3/4 x 7/8 AF OillE Spanner
T/I/I
I
90° Adjustable Spanner
B500/IO/I
1 8" Parrot Nose Adjustable Spanner
TOOLS AND EOUIPMENT NOT SUPPLIED:
Vacuum pump
Tool kit
Multimeter
Wire preparation tools
PREPARATION:
Examine the packing case and inform the shipping insurers immediately if damaged
2.
Unpack and check ofT the contents against the Packing List. Note that the Standard Parts
Supplied and Standard Tools Supplied lists are for guidance only. The Packing List supplied
in the product envelope is fully detailed and accurate.
3
The refrigerant flow transducer and the pressure transducers are to be introduced into the
refrigerant system. To achieve this without loss of charge, the RI34a must be pumped down
into the liquid receiver.
4
Run the compressorto facilitate pumping down
,
Slacken the gland seal on the liquid receiver back-seatvalve then close (front seat) the valve.
Retighten the gland seal.
6. The refrigerant in the refrigerant flowmeter glass tube will stan to boil then becomedry.
7.
The suction pressurewill fall to Zero bar (gauge). If allowed to continue to run, the pressure
may fall to sub-zero. Ideally, switch QfE the compressorat zero so that opening the systemwill
not causeair to rush in to fill the vacuum. A ~
positive pressureis more acceptable.
8
The Rl34a is now retained in the liquid receiver. Close (front seat) the suction valve at the
compressor(after slacking the gland seal).
9
Close the liquid stop valve at the inlet to the expansion valve, thus isolating the system to be
opened to atmosphere.
\0. Switch off and isolate the electric and water supplies to the A660 unit.
movement in the castor wheels will strain or fracture the supply lines.
Disconnect if
II. Open the main control panel to expose the DIN rail by removal of the MS hex retaining screws
12. Leave the A660 in the pumped-downcondition and proceed with bench assemblywork
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C13
DATA LOGGER PREP~RATION AND FITTING
PARTS REQUIRED:
PART No.
SFl!47
SF3!1
SFl!18
AC660/1fl
DLS/l!l
QTY
16
12
16
2
I
DESCRIPTION
MS SS Washer
MS Nylon Washer
MS x 12 Hex Head Screw
~ata Logger Mounting Plate
Data Logger with Hex key
Remove the 2mm hex socket screws with the Hex key provided and lift off the Data Logger
cover. (Refer to Figure 5 on Page CI2.)
2.
Set the binary identification on Switch S17 (see following page for method).
I
3.
Move the Hz jumper ~osuit the electrical supply, 50 or 60Hz.
4.
s.
All thennocouple grounding switches should be,!!r.. The duplex thennocouples are grounded
via the digital temperatureindicator.
I
The power supply must always be set for 240V when fitted to the A660.
6. Refit the cover but use the top four screws only. The remaining screws will not be accessible
when fitted to the A660.
7.
Remove the four rubber feet from the baseand fit the two mounting plates horizontally, in their
place.
;
8.
Fit the assemblyto the rear of the upstreamduct betweenthe Evaporator and Preheatercover.
Threadedbrass inserts:exist in the duct for this purpose. The Logger terminals must be nearest
the Evaporator. the terminal label will then be the correct way up.
C14
AC660A LOGGER
-SWITCH
S17. BINARY IDENT SWITCH
The RS232 addressof the logger must be set to identify the type of machine. The first portion
of the switch, labelled P & L on the PCB, are for identifying how many loggers are daisychainedtogether. The AC660A utilises a single logger therefore P & L are both set to the off
position.
2
The software for the straight through A660 air conditioner will have less temperaturestations
than a recirculating duct A660B air conditioner. The remaining six switches.labelled D. E. V.
I. C and E. are used to identify the machine. A660 = 25. A660B = 26 and A660C (pID Control
Upgrade) = 27.
LOGGER NUMBER
No.3
No.2
ON
OFF
ON
ON
ON
Single
Logger
OFF
OFF
OFF
No
BINARY
VALUE
SWITCH
NUMBER
2
3
4
S
6
1
8
OFF
0
OFF
OFF
I
OFF
OFF
OFF
OFF
OFF
0
-2
P
L
D
E
V
I
3
C
4
5
Single logger
off, off=O
On-I
On=2
00=4
00=8
On = 16
E
On = 32
Single logger
off, off=O
AC660 Fitted to A660 (STRAIGHT THROUGH)
LOGGER No ZERO
Bin ary
MachiRe Identity
No. 25
2
3
4
S
6
7
I
Off
0
P
Off
I
L
ON
0
D
OFF
.t
E
OFF
2
V
ON
:I
I
ON
4
C
OFF
AC660 Fitted to A660B (RECIRCULATING
LOGGER No ZERO
Bin ary
Machine Identity
No. 26
..
~
OFF
On=8
On = 16
S
E
Total = 2S
DUCT UPGRADE)
0
P
L
2
OFF
3
OFF
4
ON
S
OFF
2
6
~
1
~
.
ON
3
ON
4
S
OFF
On=l
0
-
Single logger
off, off=O
0
E
On = 2
C
00=8
On = 16
V
E
Total = 26
CIS
AC660 Fitted to A660C (pm CONTROL UPGRADE)
LOGGER No ZERO
2
3
4
Binary
Machine Identity
No. 27
,
6
7
8
OFF
0
P
OFF
I
L
ON
0
D
ON
I
E
OFF
2
V
ON
3
I
ON
4
C
OFF
S
E
Total ~ 27
l
Single logger
off, off=O
On=1
On=2
00=8
On = 16
C16
CONNECTIONS
-SWITCH
PANEL TO DATA LOGGER
PARTS REOUIRED:
Figure 2
or Figure 3
1
1
PART No.
AC660ISI1
SF4/3
SFl/47
SF3/1
SF1Il8
AC660/2/1
HC6SSISII
C7/3
QTY
I
2
8
4
6
I
I
25
Wiring Diagram, Connectionto Switch Panel (415V) Drg No 66OCO5M
Wiring Diagram, Connectionto Switch Panel (220Y) Drg No 660CO7M
DESCRIPTION
Pre-wired DIN Rail Assembly (CT & Volts)
M5 Nylock Nut
M5 SS Washer
M5 Nylon Washer
M5 x 12 Hex Head Screw
Heater Relay PCB
RS232 Socket, Statusand SampleLamps
Cable Tie
Removethe 4Ommplug from the baseof the switch panel. This hole will be the exit route for
the RS232 connector and other cablesto the Logger.
RS232. Status and Samole Lamos
2. Remove the 92mm x 92mm dummy DIN casefrom the hinged lid and fit the RS232 module in
place of it.
),
Route the RS232, status and sample cables out via the 40mrn hole. You may prefer to mark
these wires now, to avoid confusion when making the connection at the logger end.
Heater Relay PCB
4. Fit the heater relay PCB to the centre of the rear face of the switch panel. Four captive nuts
exist for this purpose. The terminal block with short red and black wires should be at the
bottom.
s,
Route the two multi-core cablesout from the PCB via the 40mm hole. Wire to the logger later.
6. Connect the Red and Black cables from the PCB to DIN rail terminals specified on the wiring
diagram.
Pre-wires DIN Rail
7. Fit the pre-wired DIN rail assemblyto the baseand to the right of the existing DIN rail.
8.
Route the
metre flying leadsout to the logger via the sparecable gland on the right.
9. Connect the short flying leadsto the DIN rail tenninals specified on the wiring diagram above.
Note that the wire from the Line Filter must passthrough the Current Transfonner to enable
compressorcurrent to be sensed. The redundantcompressorwire may be left in the loom but
cut the exposedcopper wires ofT where it was disconnectedfrom the DIN rail.
Connect to the Data L022er
10. Route all cables to the logger tenninals through the tnmking provided.
Connect all cables to the logger terntinals specified on the wiring diagram above.
12. Tidy excesslengthsand securewith cable ties. Ensurethe hinged lid can be openedand closed
without straining cables.
J. The 40mm plastic plug should be drilled or punchedout, cut and refitted to protect cablesfrom
sharp edges.
C17
CONNECTIONS
-TRANSDUCERS
TO DATA LOGGER
PRESSURE TRANSDUCERS (CHANNELS 17. 18 and 19)
PARTS REQUIRED:
Figure 4
PART No.
IM49/2
CI3156
C6I14
SF1/29
SFI/S4
T/I/I
8500/10/1
Wiring Diagram, Logger to TransducersDrg No 66OC04M
QTY
3
3
3
3
3
1
1
DESCRIPTION
PressureTransducer,-1 to +15 Bar (gauge)
P Clip for pressuretransducer
Capillary Tube with depressor
M8 x 25 Hex Head Scre..w
M8 Washer, 19 o.d.
90° Adjustable Spanner
8" Parrot Nose Adjustable Spanner
Examine the capillary coupling tubes. Note that one end contains a depressorpin and both ends
are fitted with an "0" ring. The depressorwill unseata Schraedervalve when fitted to the rear
of the pressuregauge,giving accessto system pressure.
Fit a capillary tube to each pressuretransducerwith the depressorat the free end. Use two
spannerto tighten - one to hold the hex boss of the transducer,one to turn the capillary nut.
Detach the pressuregauge housing fi"om the frame plate and rotate it to gain accessto the
Schraederpressuretappings. (The housing remains tethered by the system capillary tubes.)
4. Remove the dust caps from the Schraedervalves.
s.
Have the 90° adjustableand parrot nose spannersready. The next operation must be perfOmted
smartly to avoid loss of refrigerant charge.
6. Attach the first capillarytube,makingsureit is not cross-threaded.The first threaddoesnot
cause the Schraedervalve to open. Finger tighten the nut to reach the "0" ring seal quickly.
Finish tightening immediately, using the 90° adjustablespannerto hold the gauge tee and the
parrot nose spanneron the nut.
7.
Repeatthis operation for the other two gauges.
8. Fit the large "P" clips to each pressuretransducerand secure to the M8 captive nuts on the
pressuregauge housing.
9. The condenserinlet and outlet pressuregaugeswill be indicating pump-down pressureat this
time. Do a leak test using soap and water solution to confirm these connectionsare gas tight.
A complete system leak test will be done later.
10. Identify the cables to avoid cross-channelconnection at the logger.
II. Securethe gauge housing to the frame plate.
1
12. Route the cables to the logger via the tnmking attachedto the condenser.
13. Connect all cables to the logger tenninals specified on the wiring diagram above. Tidy excess
lengths and securewith cable ties.
CONNECTIONS
-TRANSDUCERS
DUCT DIFFERENTIAL
TO DATA LOGGER
PRESSURE TRANSDUCERS (CHANNELS 20 and 21)
Channel 2] applicable to A660B Recirculating Duct Upgrade only. However it is
recommendedthat it is connected to the Data Logger and calibrated by connecting in
parallel with the Duct Differential Manometerfor later use. Once calibrated in accordance
with the AC660B Software Upgrade Kit it may be disconnectedand stored.
PARTS REQUIRED:
Figure 4
PART No.
RMXlS/S
RMX29/1
C48/2
E2/22
E4/16
IM20/S
SFI4/1
CI9/6
Wiring Diagram, Logger to TransducersDrg No 66OC04M
QTY DESCRIPTION
6cm 1/4" Nylon Tube
300cm 6rnrn bore Clear PVC Manometer Hose
3
6rnrn Plastic Tee for manometerhose
6
Crimp Terminal, 3.5mm fork
2
3 core, O.5mmCable, 4m long
2
Differential PressureTransducer,0 to 25.4mm H2O WG
4
Self Tap x 9.5 Diff PX
10 Self Adhesive Cable Clip
Cut the 1/4" nylon tube into four equal lengths and fit to the pressureports on the Differential
Pressuretransducers. They will then match the inclined manometerport size.
2.
Fit the transducersto the ducting, adjacentto the inclined manometers. Pre-drilled fixing holes
exist in the duct for this purpose.
3.
Preparethe 3-core cable by fitting the crimp terminals to the transducerend.
4.
Route the cable back to the logger and apply self-adhesiveclips to the duct or cable tie to the
frame to keep it tidy.
5.
Connect the cable to the logger tenninals specified in the wiring diagram.
6.
Connect the manometer hoses by teeing into the existing inclined manometer hoses.
Schematic Diagram may be used as a guide.
The
f11
n
~
~
~
~
I~
I A660 REFRIGERANT FLOWMETER ASSEMBLY (PART NO. AC660/6/1J
r
NOTE ORIENT A TION
FIGUft
6
-=
C19
C20
CONNECTIONS
-TRANSDUCERS TO DATA
LOGGER
REFRIGERANT FLOW TRANSDUCER (CHANNEL 17)
PARTSREQUIRED:
Figure 4
PARTNo.
AC~6/1
PFI/34
EJ/124
AC66OI3/1
Wiring Diagram. Logger to TransducersDrg No 66OC04M
QTY
1
1
1
2
DESCRIPTION
Refrigerant Flowmeter 1\2, O.OSto 1.6 I/min
3/8 Flare Copper Gasket
Flowmeter Lead
3/4 x 7/8 AF OJDE Spanner
The end fittings must be gas tight on completion. Keep all parts clean
2.
Examine the refrigerant pipelines to identify the location for fitting the refrigerant flow
transducer. Below the glass tube refrigerant flowmeter there is a copper tube, 125mm long,
connectedto a 3/8" male flare equal coupling. The combined length of these two is identical
to the length of the new sub-assembly.
3
Removal of this length must be perfonned with care to avoid breaking the glass tube. Two
colTectly sized spannersare provided. Use the 3/4 AF spannerto hold stationary the fitting at
the baseof the glass tube. Use the 1/8 AF spannerto undo the flare nut. Tilting the fitting will
crack the glass.
4
DiscOMect the lower flare nut and remove the combined tube and male flare.
oS
Blo\v through the flow transducerby mouth, noting the direction-of-flow arrow, to verify the
turbine rotates freely.
6.
Note the 3/8" female flare coupling fitted to the outlet side. Refer to Figure 6 on PageC19.
A copper flare gasket will provide the seal between here and the inlet to the glass tube
flowmeter.
1
Hold the flow transducervertical and drop the 3/8" flare copper gasketinto the outlet side. Use
a ballpoint pen to align centrally then hand tighten the complete assemblyonto the 3/82 male
flare at the bottom of the glass tube flowmeter.
8.
Couple the flare nut at the inlet side of the flow transducerand tighten both ends using the 3/4
AF and 7/8 AF spannersprovided.
Plug in the flow transducersignal lead by locating the keyway, then tighten the nut.
10. The body of the flow transducermay be rotated around the vertical axis, having swivel end
fittings.
Route the cable to the Joggervia the trunking attachedbeneaththe ducting.
12. Connect the cable to the logger tenninals specified on the wiring diagram.
13. Tidy excesslengths and securewith cable ties.
C2t
- TRANSDUCERS
CONNECTIONS
COMBINED
Note:
-I.aH
TEMPERATURE
TO DATA LOGGER
PROBE
(CHANNELS
23 and 24)
Channels23 and 24 applicable to A660C PID Control Upgrade only.
PARTS REOUIRED:
Figure4
PARTNo.
EJ/6S
1
Wiring Diagram, Logger to TransducersDrg No 66OC04M
QTY DESCRIPTION
30Ocm 5-core Cable (stowed inside the PID enclosure)
The output from the combined probe may be shared between the PID controllers and the Data
Logger.
2. Gain accessto the PID DIN rail by removal of the transparentcover.
3.
Locate the coil of cable, which is already connectedto the DIN rail tenninals from where the
signal may be taken.
4.
Route the 3 metre cable out via the spare cable gland provided.
5.
Route the cable to the logger via existing trunking or cable tie to the frame to keep it tidy.
6. Connect the Yellow, Clear and Blue wires to the logger tenninals specified on the wiring
diagram.
C1.1.
AC660A COMPUTER LINKED UPGRADE KIT
COMPLETION
OF INSTALLATION
PARTS REQUIRED:
E3/249
I
E514
2
Ens
3
SFI4/1
4
£4514
£43/3
A660/ICNI
C45/3
C45/2
I
I
I
I
I
E5/133
,
Data Logger Power Supply Cable, 13A plug
13A Plug
3A Cartridge Fuse
4-gang Extension Lead
Self Tap x 9.5 Diff PX
External SeriaJLead, 25F
25M to 9F Serial Converter
10/II mm Open law Spanner
CompressorCharging Valve Key
Refrigerant Charging Line
All channels are now connectedwith the exception of the temperaturechannels. Install the
A660A Digital TemperatureUpgrade Kit now in accordancewith Appendix A of this manual,
but return to this section before doing a functional test.
2.
If already fitted, simply plug in the tenninal blocks to the logger edgeconnector. Take care not
to cross channels.
3
The logger power supply lead must be fitted with the 3A fuse provided
Plug into the logger and the 4-gang socket outlet.
,
Connect the RS232 9-pin serial link to the logger
6.
Connect the external serial lead by plugging into the socket at the Status/Samplelamps.
1.
8.
The second4-gang extension lead is provided for use by a computer, monitor or printer, able
to use the 220-240V AC available from the A660 socket outlet. This may be at SOor 60Hz.
The refrigerant system is now contaminatedwith air and must be leak testedbefore use.
This can be achievedby one of two methods:
Method I: With Vacuum Pump
I
Removethe cap nut from the compressorsuction valve and connectthe vacuum pump. Set
the valve to the mid-position and start the vacuum pump.
2.
Open the refrigerant stop valve at the inlet to the expansionvalve. The vacuum pump now
has access to the system from liquid receiver stop valve, through the evaporator to
compressorsuction valve.
],
Run the vacuumpump to achieve IOmmHg (Abs) to ensurethat no moisture remainsin the
system.
4
Open (back seat) the suction valve, disconnectthe vacuum pump and refit the cap nut
s,
Open the liquid receiver front-seatedvalve to fill the lines with refrigerant pressure,then
close again.
6.
Use soap and water solution to check for refrigerant leaks. If available, an electronic leak
detector for R 134a is preferred. Rectify any leaks found before continuing.
Method 2: Without
vacuum RumR
Refrigerant pressurecan be usedto push the air out if a vacuum pump is not available.
2
3.
4.
s.
Confirm that the compressor suction valve is still front-seated and cap fitted.
refrigerant stop valve at the inlet to the expansionvalve is still closed.
Open the liquid receiver front-seatedvalve to fill the lines with refrigerant pr~re,
close.
then
Use two spannersto slacken the nut at the entrance to the refrigerant stop valve (at the
expansion valve). Allow air and a sma11amount of refrigerant to leak out before retightening.
Use soap and water solution to check for refrigerant leaks. If available, an electronic leak
detector for Rl34a is preferred. Rectify any leaks found before continuing.
6.
Open (back seat) the suction valve.
1.
Open the refrigerant stop valve at the inlet to the expansion valve.
Functional Test after Air Pur2e
I.
2.
3.
4.
Restorewater and electrical supplies.
Switch on the main switch, the fan will run and the digital temperatureindicator will illuminate.
Observe the Data Logger at the moment of switching on. Refer to Figure I on Page C2 or
Figure 5 on PageCIZ. The Sample/FaultLED should flash a few times as it performs a selftest, then go out. This LED will flash each time a logging sample is taken when the computer
is connected. The Power LED will glow continuously when power is supplied.
Start the compressorand slowly open the liquid receiver valve until fully back-seated.
s. Refrigerant flow in the glass tube flowmeter should become gas free liquid, i.e. no bubbles.
(Assuming no significant loss of charge.)
6. The pressure/temperaturerelationship should align with the P-h chart. High pressureis a sign
that air has enteredthe system. In this case,refrigerant recovery, vacuum and re-chargeare the
only cure.
,.
If satisfactory, continue with loading software and proving all channels.
For referencepurposes,Figure 7 {PageC24 gives the wiring details of the internal serial lead and
Figure 8 (Page C25) gives the details of the external serial lead. If accidentally damaged,the leads
can be easily repaired.
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Must be preceded by
AC660A Computer linked Upgrade Kit
Dl
AC660B COMPUTER LINKED SOFIW ARE UPGRADE KIT
SOFTWARE INSI'ALLATION
PARTS REOUIRED.
PART No.
AC6fJJB
QTY DESCRIPTION
1 ComputerLinked UpgradeSoftware
comprising
31h..Floppy Disk, pre-configuredDEAT97
Software RecordSheet
SoftwareUser'sGuide- VersionHEAT97.EXE, Issue1.01DI.SIOl/Soft
Copyright Notic~
COMPUTER REOUIREMENTS:
IBM PC or compatible; 286 processoror higher; 1MB RAM; DOS or Windows; VGA or colour
monitor; RS232serial port COMI or 2, and 31/28floppy drive.
PRINTER TYPE:
If hard copy is required during logging or data retrieval - EPSONcompatibledot matrix printer
connectedto the LPTI parallel port.
PLOTrER TYPE:
For plotting am plot overlay of retrieveddata- 2-pen (minimum). RS232serial COMl or COM2.
9600 baudand HPGL compatible.
DISK CONTENTS:
1. HEAT97.EXE is the pre-configuredoperatingsoftware. When usedON LINE, the RS232
seriatlink must be connectedbetweenthe Data Logger and the PC. Data may be monitored
on screenand savedto disk.
2.
HEA 1'97.EXE may alsobe usedwid1Outthe DataLoggerconnectedwhenOFF LINE hasbeen
selected. This facility allows reviewingpre-recordeddata remove from the laboratory.
3.
CONVERT .EXE facilitates export to spreadsheet such as ExcelTM,
4.
TALK.EXE
allows interrogation of individual channels at maximum update rate.
FUroRE SOFrW ARE UPGRADES:
Data logging software is suppliedwith this AC660A Upgradeas an interim measure. Windows
softwarewill be suppliedwithout further chargewhen available.
Windows software will include real time Psychrometric Chart and Refrigeration Enthalpy plotting.
Options to display raw data, calculated results, or convert numeric data to spreadsheet compatible
format.
The logging software, however, will still have a place when training mechanical engineers.
Understanding data acquisition, transducers and presentation of data to non-technical personnel is
essential.
P.A. Hilton Ltd. has been working with the United Nations Industrial Development Organisation
to help developing countries to make the change from Ozone depleting CFC refrigerants. The Data
Logger has proved an invaluable tool for showing refrigeration plant performance. before and after
conversion.
D2
GETfINGSTARTED
I
2.
Setup yoor COmplierwid1inreachof thepower supplyandthe RS232serial link connectedto
the A6(i} unit.
Com:M:ct
the serial link to COM I or 2. Usethe 25 109-pin converter if required. DQ00( use
a port assigned10a serial mouse.
3. Connectyour Dot Matrix printer to the parallel port, if applicable.
4.
5
After complying widt your local IT regulationsfor virus checkingof new software, copy this
disketteto a new directory or folder called HEA1'97. The originals shouldbe kept as a back
up.
Switch on the A~
to power up the logger aIxi establishserial communication.
6. From the C: drive, doubleclick on REAT97.EKE in its C:\HEAT97 directory.
7
Put d1CDnJseto ~
side. Navigationthroughmostof d1eprogrammeis by useof the up/<kJW,
- T1-, or useof the highlightedor !Lnderlinedletter keys.
left/right arrow keys,
8. The first screenis the pre-configuredSystemconfigurationmenu:
9
PressD to move the highlight to log-all nata file.
10. PressEnter- to changethe file name, type the new name,suchas XXXI.
11. PressL 10DX>ve
to me LoggerJX)rtdlat dte seriallink basbeen~ted
to in 2 above. Press
Enter- to switch betweenCOMl and COM2 as appropriate. PressEnter to ~ept.
12. Press M [0 move the highlight to Main menu.
13. PressEnter- to accept
D3
14. PressY to savethe change.
15. A smiley face@ appearsin d1etop left of dIe screen. Note that d1ecentre Red LED is 00, the
data logger will flash as each channel is programmed. This can take up to 30 seconds.
16. Wait, then the Main menu appears:
<Enter> to confirN
17. Press D to move the highlight to collect & Qisplay data, or use the down arrow to move the
bar.
18. PressEnter"" to accept.
D4
19. The collect & l2isplay menuappears;
<Enter)
to confi,..
20. PressEnter'" to acceptNumerical display
21. The active channelsare displayed
Note: This is not real data. but analyse each channel to check the data is reasonable.
Switch on a pre-healer arKi expect an iocrease in TJ. Also expect logic .ON. indication from
Channel 31 or 32.
22. The smiley face appearsin the t~ left of the screen. Data is being savedin the root directory
of the C: drive in a file namesXXXI aIx1at the interval chosen1inthe Systemconfiguration
menu.
23. To stop logging. pressthe FI functionkey
DS
24. The collect &.D.isplaymenuappears:
<Enter> to confirm
25. PressM to move the highlight to Main menu, then Enter-.
26. The main Menu appears:
<Enter> to confirN
27. PressR to selectRetrievestoreddata. then Enter28. The Retrieve storeddata menuappears
06
<Enter)
to
confir.
29. PressEnter to acceptNumerical display. the data file list is offered
30. Accessto all datafiles may be gainedfrom the abovescreen. Only one data file exists at this
time so pressingEnter"" will fiOOthe default file.
31. ~ retrieveddataappears,startingwith Data Point I. PressingN for Next screenwill advaoce
through the storeddata.
-"i~1
~
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"-8'.'-
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Label
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18.288
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,
T~ Ed RETURN
2e . 6'8
.C
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11
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TI1Fd FRESH
T13 EUAP OUT
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21.6~
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EUAP OUT Px
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21
23
FRESH DIFFP~
RETURN TEMP
I.t REHEAT
25
21
29
R1~ FlO~
UPPERH2o2kW
31
l,t
JJ
C~ESSOR
PREHEAT
255.289
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8.518
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66.Z88
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11
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T8 Dw t I)R(X»I
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T11f COHO IN
SUPP\.V UOLTS
COND IN Px
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FAN YOLTACE
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HonG
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D7
32. This endsthe -Getting Started- guided toUT.
33. PressM for the Retrieve storeddataMenu.
34. PressM for the main Menu.
35. PressEnter- to accept.
36. Press Q to Quit to OOS.
37. Exit the MEAT91 programmefrom DOS or closethe Window.
The aboveprocedurehas given experienceof:
.
.
.
.
Navigating through the menusand options
Collect & display of data in numeric format
Retrieval of storeddata in numeric fonnat
All channelshave beenshown to function, but may needfurther calibration.
The Software User's Guide should now be read to discover the full potential of tb~ data
logging system.
D8
TRANSDUCER CALIBRATION
Factory fitted AC660A Computer Linked Upgrades will arrive in a calibrated condition, but
cmtomer imtaJled upgradesshould be followed by t~ procedure.
Calibration is also a useful student training exercise, being representativeof the engineering
problemswhich they will encounter.
~bratioo is requiredto makeeachtransdoceriOOicate
correctly. The subjectis explainedin'the
Software User's Guide, sectionCANCaN 1.0.0 (Page22 onwards)
All transd\K:Crsused in dJe kit have an OUqxIt proponional to the measuredvalue. Thermocouples
produce approximately 40 microvolts for each ilegree of Celsius. The refrigerant transducer output
ilx:reases by 1 Volt DC for each 3.2 Bar ilx:rease in pressure. The flowmeter produces one pulse
each time a blade of its paddle wheel breaks a beam of light. The frequency (Hz) is therefore
proportional to flow rate.
To conven theseoutputsinto engineeringunits, we mustrefer to the DataSheetwbkh accompanies
each sensor. From the manufacturersstatedrangeand outputwe can calculatean exchangerate
Stx:has PSI/Voit or litres/~.
~
plottedin x/y graphform thesevaluesprodocea sl~ (K2)
and zero offset (Kl).
Kl
= Engineeringunits to display when transduceroutput = zero electronicunits. e.g.
PressuretransducerKl
- -4.2 Bar (Gauge)at zero volts output
Pressure
transducer
Kl = -00.9 PSI (Gauge)at zero volts output
Refrigerant flow transducerKl = 0 g/secat zeroHz output
K2 = Engineeringunits representedby eachunit of electronicoutput, e.g.
PressuretransducerK2 = +46.4 PSlNolt
Refrigerant flow transducerK2 = 0.00 g/puise
Duct differential pressuretransducerK2 = 5mmHzONoit
If using Excel be careful (0 have the unirs of inpu( (0 the logger on the baseline (x a.,-is)and the
measuredvalueon the vertical (y axis). The answerwill thenbe preseoredin an acceprableform:
mm/Volt or g/pulseor Amps/IDAor .C/mV. etc.
The pre-configuredHEAT97 "conversionfactors file- 6l«:ON usesthe abovecalculatedKl and
K2 valuesto converttransduceroutputinto unitsdisplayedon screen. The transduceroutputshave
been regarded as li~ar. producing a straight line. Non-li~
curves require the use of the
polynomial equationand K3 and K4 (seethe SoftwareUser's Guide).
During the "Getting Scaned" tests in the previous section lhere may have been some disagreement
betWeenme value displayed on screen and me indication by the inclined manometer or refrigerant
flowmeter. For example, calibration dlroogh software enablesus to make the transducers agree wim
the instruments.
For the purpose of this exercisewe sbaJl regard the manual indicator as the 8Master8 gauge.
A secondset of configurationftIes hasbeensuppliedon disk to enablefast gatheringof data from
the channelsundergoingrecalibration.
Use of the TALK.EXE programmemay also be explored later TALK. or Windows TM Hyper
D9
Terminal, allow any single channel to be accesseddirect from the keyboard and displayed
repetitively. Note that TALK-EXE can only Operate1via
COMl using upper casekeys, i.e. Caps
Lock. Refer to the SoftwareUser's Guide.
CALmRA TION PROCEDURE
Switch on the A6fJ>to power up the logger andestablishserial communication.
2.
3.
From the C: drive, doubleclick on HEA~.EXE
in its C:\HEAT97 directory.
Put die mouse to one side. Navigation dtrOUghmost of the progranune is by use of the up/dow,
left/right arrowkeys,- r 1-, or useof the'highlightedor !.lnderlinedletterkeys.
4. The flfSt screenis the pre-configuredSystemconfigurationmenu. For example,
,.
6.
7.
The file namesshould be changedto those shown below. Move the highlight bar to select
.c.hannelconfig. file, pressEnter-. Type the new file name66OPRODthen pressEnter again.
Repeat the procedureto amendthe conversionfactors and log-allllata file nameto 6roCAL
and PROD 1 as shown below.
I;
PressL to moveto the Loggerport that the serial link hasbeenconnectedto. PressEnter- to
switch betweenCOM I or COM2 as appropriate.
I
Move to Main menu(henpress Enter-.
DIO
8
PressY to savethe change
9.
A smiley facee appearsin the top left of the screeD.
10. Wait, then the Main menuappears
<Enter> to confir.
ll. Press D to move the highlight to collect &. D;isplaydata, or usethe down arrow to move the
bar.
12. PressEnter- to accept.
13. The collect & Display menuappears
<Enter> to confir8
14. PressEnter""to acceptNumerical display
15. The new list of -.:.tivechannelsis displayed. Note that the Value displayed is in default units
of Volts or Hz. The conversionfactors for thesecbarmelshavebeenleft at default:
,
Dll
16. If the A660B Recirculating Duct UpgradeKit is not fitted to your A660 unit there will be no
Fresh Air Intake inclined manometer,only a Duct manometer. In this caseChannel21 may
be ignored.
However, in the event that the Computer Upgrade Kit will la(er be used with an A6WB
Recirculating Duct UpgradeKit, or that the A6WB is already fitted, it will be necessaryto
calibrate the Fresh Air Intake transducer.
If the A660B RecirculatingDuct UpgradeKit is not yet fitted, the Fresh Air Intake transducer
may be coupledto, andcalibratedagaimt, the Duct Differential Pressureinclined manometer.
17. Vary the Fan SpeedaJxiVolume Control (ChanlM:121
only) to increasethe ioclined manometer
readings from minimum to maximum in Imm H2O steps. At each setting record the volts
output for Channels20 and 21. (Photocopythe observationsheeton the next page.)
18. Switch on the compressorto causethe refrigerant flowmeter to function.
19. Run without pre-heatand at minimum fan speedto reducethe load on the evaporator to a
minimum. If the recirculatingduct is fitted, 100%recirculationof chilled air will achievethe
lowest refrigerant flow rate.
20. Record the Hz (Channel27) and the indicatedrefrigerant flow rate at this setting.
21. Now increasethe evaJX>rator
load to maximum(0 achievemaximumrefrigerant flow. i.e. both
pre-heaterson and maximum fan speed.
22. Record the Hz and indicatedrefrigerant flow at this setting.
23. Use the data gatheredto constructnew curves and calibration factors for the abovechannels.
This may be donelonghandasexplainedin the SoftwareUser's Guide, or by use of third party
spreadsheetsoftware.
24. The pre-configured conversion flie must now be amendedto the more correct Kl and K2
values.
~
012
RECORD V ALVES to ~eneratean EXCEL SPREADSHEET
Note, depending upon local supply voltage, the maximum manometer reading may be below
l2mm H.O.
CHANNEL20
DUCT DIFFERENTIAL PRESSURE
INCLINED MANOMETER mm H1O
RECORD
VDC'
SET TO APPROX mm
RECO_~_~~~~
1.
3
4
5
6
7
.
,
10
11
u
ResultiJl,g;calibration factors
1:1-
K2-
CHANNEL 21
DUCT DIFFERENTIAL PRESSURE
INCUNED MANOMETER mm 810
RECORD
VDC
SF:r TO APPROX IDD1
RECORD ACTU.~ DUn
2
J
4
5
6
7
8
It
10
11
U
~~I!i~_ca!i~~~ factors
CHANNEL
K.l-
27
Rl34a VARIABLE AREA FLOW
RECORD Hz
Resulting calibration factOrs
K2-
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D17
AMENDING CONVERSION FACTORS
1
Switch on the A6a> to power up the logger andestablishserial communication.
2.
From the C: drive. double click on HEAT97.EXE in its C:\HEAT97 directory.
3.
Put the mouse to one side. Navigationthroughmostof the programmeis by useofdte up/dow,
left/rightarrowkeys,- r 1-, or useof dtehighlightedor !,!nderlinedletterkeys.
The first screenis the last usedSystemconfigurationmenu.
4.
s
6.
Move the highlight bar to select{;.hannelconfig file, pressEnter-. Type the new ftIe name
66OCHAN then pressEnter- again.
Repeatthe procedureto amendthe conversionfactors and log-all nata file nameto 66OCON
and XXX I as shownbelow.
1.
Move to Main menuthen pressEnter"", PressY to savethe change.
8.
A smiley facee appearsin the top left of (he screen
9.
Wait, then the Main menu appears
018
<E..l~r>
to c.;onrlr..
--
10. PressC to moved1ehighlight to,CbanDe1
configuration.or usethe00wn arrow to move~ bar
II.
Press Enter. me .(:haImel configuration appears
!f!i~r""1-,
"'"" -"
1Jrf""
12. Usethe arrow keys(0 moveacrossto the ConversionNo column and down to Channel20. as
above.
3. PressEnter- aM the conversionfactors dialoguebox is superimposed
D19
14. Use the arrow key to moveacrossto Kl column. PressEnter- then type in the new KI value
from the Excel spreadsheet.In this examplewe changeKl to 1.56. K2 to 5.31.
8:;:.
15. We enteredthroughChaIU1e120
and must exit the sameway. Move the highlight to 20.
s
s
0
21
22
23
Polyno8ial
Polyno8ial
Polyno8ial
Polyno8ial
1.56
e
e
-29
5.31
5.98
29
29
9
e
9
e
If the FreshAir transducerhas beencalibratedandK 1 and K2 factors are known, then repeat
the aboveprocedurefor Channe121starting from Point 12 overleaf.
16. PressM for Menu, the ~hannel configurationreturns:
~
D20
17. Notice the rangehasdefaultedto encompassthe total rangeof a +8V -8V channel. If this is
not adjustedto representthe range of likely duct pressures,the resolution of the graphical
display would be unsuitable.Ametxl the UpperLimit to 15mmH2OaOOLower Limit to zero:
19
28
21
kN.2
DIFF Px.. H2o
FRESHDIFFPx.. H2o
COND OUT Px
DUCT
18. Channel 21 may be ~00ed
19
29
21
L
L
L
1698
lS
lS
e
k-~
8
e
8
y
y
y
in the same way
19. The fmal example will be the Refrigerant Flow transducer Move the highlight to select
Channel21 for amendment.
-
20. Press Enter- to see the conversionfactors dialogue oox
channel, input optionsare offered:
21. Press Enter"" aOOchoose frequeocy from the following:
1
21
23
22
~AE$H
2..
25
AETUtON
A~
AETUAN
TE"~
~"'N
~OWEA
1G~
Ae:HE"'T
DX~~P.
--
H~o
AH7.
oC
WATTS
Non-
~
~~~;~;::.,;~.-:0
~~ P..-J.od
..
23
z',
'-
.--a
e..
Becausethis is a digital input
D21
22.
Press
.
Enter
to
see
17
EUAP
OUT
18
CO
IN
19
DUCT
21
FRESH
29
NO
the
conversion
CONDDIFF
OUTP
I1
DIFF
l1li26
28
factors
Polyno8ial
Polyno8ial
dialogue
box:
e
9
9
1
9666
1
e
e
e
8
8
8
23. Ameoodle CbaIU1el27K2 factor to thenew calculatedvalue. In this example.0.0948g/pulse.
11
18
19
28
21
~-
24. Rememberto exit via No 27. PressM for Menu or the ~pe
returns:
key. the ~hannel configuration
25. Move the highligi)t to Return and pressEnter. Note how the Channel27 unitShavedefaulted
back.to Hz. Amend to read g/sec again. Also the rangehasdefaultedto the maximum g/sec
at maximumHz measuringby the logger,4(XX)Hz. Amendthe Upper Limit and Lower Limit
to the valueson the variable area flowmeter, i.e. 30 and 4.
~""'adl;c
,...~
1S
16
11
18
19
29
21
22
23
lit
2S
26
21
28
29
39
31
32
II ~~1;l8!J
-~~
.c
CC
"c'~~
e
e
e
e
e
9
9
59
9
9
9
9
9
9
e
9
8
e
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y
y-
D~2
26. PressM to get back to the Main menu. PressY to savethe changesand wait.
27. Verify all ch~ls are oow functioningby logging somedata. Comparethe on screenvalues
with the iOOicationson the inclined manometeram refrigerant flowmeter. they should now
agree.
28. It is recommendedthat a back-upcopy of the configuration files is madeso that if files are
altered in error they can be recoveredfrom the back-up disc. It is recommendedthat the
original AC~ pre-configuredsoftwaredisc suppliedwith the AC~B Software Upgradeis
usedfor this pnrp>se.
29. The following flies will havebeenmodified as part of the calibrationprocess
6(OCHAN.DFT
6(OCON .DFT
SYSTEM.DFT
XXXI
To make a back-upof thesefiles copy them from their location on the comguter hard disc
to the AC6ro preconfiguredsoftwaredisc. The files will be loca1edwith the HEAT97.EXE
programmein the directory createdfor this purposewhen the softwarewas loaded.
Note that the files will havethe samenameas the original versionson the floppy disk and ~
copies on the flORD! d~ should be overwritten.
0
n
~
~