ASHRAE
POCKET GUIDE
for
Air Conditioning, Heating,
Ventilation, Refrigeration
I-P
9th Edition
ASHRAE · 1791 Tullie Circle, NE Atlanta, GA 30329 · www.ashrae.org
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1/18
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Library of Congress Cataloging-in-Publication Data
Names: ASHRAE (Firm), author.
Title: ASHRAE pocket guide for air conditioning, heating, ventilation,
refrigeration.
Other titles: Pocket guide for air conditioning, heating, ventilation,
refrigeration
Description: 9th edition, I-P. | Atlanta, GA : ASHRAE, [2017] | Includes
index.
Identifiers: LCCN 2017058775| ISBN 9781939200822 (softcover : alk. paper) |
ISBN 9781939200846 (PDF)
Subjects: LCSH: Heating--Equipment and supplies--Handbooks, manuals, etc. |
Ventilation--Handbooks, manuals, etc. | Air conditioning--Handbooks,
manuals, etc. | Refrigeration and refrigerating machinery--Handbooks,
manuals, etc.
Classification: LCC TH7011 .A38 2017b | DDC 697.9--dc23 LC record available at https://lccn.loc.gov/2017058775
ASHRAE Staff
Special Publications Mark S. Owen, Editor/Group Manager of Handbook and Special Publications
Cindy Sheffield Michaels, Managing Editor
Lauren Ramsdell, Assistant Editor
Mary Bolton, Editorial Assistant
Michshell Phillips, Editorial Coordinator
Publishing Services David Soltis, Group Manager of Publishing Services and Electronic Communications
Jayne Jackson, Publication Traffic Administrator
Publisher
W. Stephen Comstock
Updates and errata for this publication will be posted
on the ASHRAE website at www.ashrae.org/publicationupdates.
CONTENTS
Preface........................................................................................................................viii
1
Air Handling and Psychrometrics
Air Friction Chart .....................................................................................................1
Velocities vs. Velocity Pressures ............................................................................2
Noncircular Ducts....................................................................................................2
Fittings and Flexible Ducts......................................................................................2
Duct Leakage......................................................................................................3–4
Fitting Losses..........................................................................................................5
Circular Equivalents of Rectangular Ducts .........................................................6–7
Flat Oval Duct Equivalents......................................................................................8
Velocities for HVAC Components ...........................................................................9
Fan Laws ........................................................................................................11–12
Types of Fans .................................................................................................13–20
Fan System Effect.................................................................................................21
Psychrometric Chart .............................................................................................22
Air-Conditioning Processes.............................................................................23–25
Enthalpy of Air.......................................................................................................26
Standard Atmospheric Data..................................................................................27
Moist Air Data .......................................................................................................27
Space Air Diffusion .........................................................................................28–29
Principles of Jet Behavior ...............................................................................30–32
Airflow Patterns of Different Diffusers .............................................................33–35
Mixed-Air Systems ................................................................................................36
Fully Stratified Systems ..................................................................................40–41
Partially Mixed Systems........................................................................................42
Return Air Design..................................................................................................44
2
Air Contaminants and Control
Air Quality Standards ............................................................................................45
Electronic Air Cleaners .........................................................................................46
Bioaerosols ...........................................................................................................46
Filter Installations ..................................................................................................46
MERV Parameters ................................................................................................47
Filter Application Guidelines .................................................................................48
Indoor Contaminant Sources ..........................................................................49–51
Gaseous Contaminants by Building Materials ................................................52–53
Kitchen Ventilation ..........................................................................................54–66
3
Water
Pump Terms and Formulas ..................................................................................69
Pump Affinity Laws ...............................................................................................69
Application of Affinity Laws ...................................................................................70
Net Positive Suction Characteristics ...............................................................71–73
Typical Pump Curves............................................................................................73
General Information on Water...............................................................................74
Mass Flow and Specific Heat of Water .................................................................75
Freezing Points of Glycols ....................................................................................75
Vertical Cylindrical Tank Capacity ........................................................................76
Horizontal Cylindrical Tank Capacity ....................................................................76
Volume of Water in Pipe and Tube .......................................................................77
Water Pipe Friction Chart, Copper........................................................................78
Water Pipe Friction Chart, Plastic .........................................................................79
Water Pipe Friction Chart, Steel ...........................................................................80
Friction Losses in Pipe Fittings .......................................................................81–86
4
Steam
Steam Table..........................................................................................................87
iii
Steam Chart..........................................................................................................88
Steam Pipe Flow Rate ..........................................................................................89
Steam Pipe Capacities....................................................................................90–91
Steam Pipe Capacities—Return Mains and Risers ..............................................92
5
Piping
Steel Pipe Data ...............................................................................................93–95
Copper Tube Data ..........................................................................................96–98
Properties of Plastic Pipe Materials ..............................................................99–100
Pipe, Fitting, and Valve Applications...........................................................101–109
Thermal Expansion of Metal Pipe .......................................................................110
Hanger Spacing and Rod Sizes..........................................................................110
6
Service Water Heating
Service Water Heating System Elements ...........................................................112
Legionella pneumophila ......................................................................................112
Load Diversity .............................................................................................113–114
Hot-Water Demand for Buildings ........................................................................115
Hot-Water Demand per Fixture...................................................................116–118
Hot-Water Flow Rate ..........................................................................................119
7
Refrigeration Cycles
Coefficient of Performance (COP) ......................................................................122
Vapor Compression Cycle ..........................................................................123–124
8
Refrigerants
Refrigerant Data..........................................................................................125–126
Pressure-Enthalpy Chart—R-22 .........................................................................127
Property Tables—R-22 ...............................................................................128–129
Pressure-Enthalpy Chart—R-123 .......................................................................130
Property Table—R-123 .......................................................................................131
Pressure-Enthalpy Chart—R-134a .....................................................................132
Property Tables—R-134a ...........................................................................133–134
Pressure Enthalpy Chart—R-245fa ....................................................................135
Property Table—R-245fa ....................................................................................136
Pressure Enthalpy Chart—R-404A .....................................................................137
Property Table—R-404A.....................................................................................138
Pressure Enthalpy Chart—R-407C.....................................................................139
Property Table—R-407C ....................................................................................140
Pressure Enthalpy Chart—R-410A .....................................................................141
Property Table—R-410A.....................................................................................142
Pressure Enthalpy Chart—R-507A .....................................................................143
Property Table—R-507A.....................................................................................144
Pressure-Enthalpy Chart—R-717 (Ammonia).....................................................145
Property Tables—R-717 (Ammonia)...................................................................146
Pressure Enthalpy Chart—R-1233zd(E).............................................................147
Property Table—R-1233zd(E) ............................................................................148
Pressure Enthalpy Chart—R-1234yf...................................................................149
Property Table—R-1234yf ..................................................................................150
Pressure Enthalpy Chart—R-1234ze(E).............................................................151
Property Table—R-1234ze(E) ............................................................................152
Comparative Refrigerant Performance .......................................................153–154
Refrigerant Line Capacities—R-404A.........................................................155–156
Refrigerant Line Capacities—R-507A.........................................................157–158
Refrigerant Line Capacities—R-410A.........................................................159–160
Refrigerant Line Capacities—R-407C.........................................................161–162
Refrigerant Line Capacities—R-22 .............................................................163–164
Refrigerant Line Capacities—R-134a .........................................................165–166
Oil Entrained in Suction Risers—R-22 and R-134a ....................................167–168
Oil Entrained in Hot-Gas Risers—R-22 and R-134a...................................169–170
iv
Refrigerant Line Capacities—Ammonia (R-717).................................................171
Liquid Ammonia Line Capacities.........................................................................172
Lubricants in Refrigerant Systems ......................................................................173
Secondary Coolants............................................................................................173
Relative Pumping Energy ...................................................................................174
9
Refrigerant Safety
Safety Group Classification.................................................................................175
Data and Safety Classifications for Refrigerants and Blends .....................176–181
10
Refrigeration
Transmission Load..............................................................................................183
Product Load.......................................................................................................185
Internal Load .......................................................................................................186
Packaging Related Load.............................................................................187–189
Infiltration Air Load ..............................................................................................190
Equipment-Related Load ....................................................................................190
Safety Factor.......................................................................................................190
Liquid Coolers .............................................................................................192–197
Forced-Circulation Air Coolers....................................................................197–198
11
Air-Conditioning Load Data
Cooling and Heating Loads.........................................................................199–200
Heat Flow Through Building Materials ................................................................202
Thermal Resistance of Plane Air Spaces ...........................................................203
Surface Conductances and Resistances ...........................................................204
Emissivity ............................................................................................................205
Thermal Resistance of Ventilated Attics .............................................................206
Thermal Properties of Materials..................................................................207–212
CLTDs for Flat Roofs ..................................................................................213–214
CLTDs for Sunlit Walls................................................................................215–216
Solar Cooling Load for Sunlit Glass ....................................................................217
Shading Coefficients for Glass............................................................................218
Heat Gain from People .......................................................................................219
Heat Gain from Lighting and LPDs .............................................................220–223
Heat Gain from Motors................................................................................224–225
Heat Gain from Restaurant Equipment.......................................................226–230
Heat Gain from Hospital and Laboratory Equipment ..................................231–232
Heat Gain from Office Equipment ...............................................................233–238
Display Fixtures Refrigerating Effect...................................................................238
12
Ventilation
ASHRAE Standard 62.2-2016 ....................................................................239–240
ASHRAE Standard 62.1-2016 ....................................................................241–244
Procedures from ASHRAE Standard 62.1-2016.........................................244–253
Normative Appendix A from ASHRAE Standard 62.1-2016 .......................253–256
Design Parameters for Health Care Facilities.............................................257–258
Operation and Maintenance........................................................................259–260
13
Energy-Conserving Design
Sustainability.......................................................................................................261
Energy Efficiency Standards...............................................................................262
Climate Zones for United States Locations.........................................................263
14
Electrical
Characteristics of AC Motors ..............................................................................264
Motor Full-Load Amperes ...................................................................................265
Useful Electrical Formulas ..................................................................................265
Motor Controllers ................................................................................................266
Variable-Speed Drives (VSDs) ...........................................................................266
v
15
Fuels and Combustion
Gas Pipe Sizing Table ........................................................................................267
Viscosity and Heating Values of Fuels................................................................268
Liquid Fuels for Engines .....................................................................................269
Fuel Oil Pipe Sizing Tables.................................................................................270
16
Owning and Operating
Maintenance Costs .....................................................................................271–272
Owning and Operating Cost Data .......................................................................272
Economic Analysis......................................................................................273–274
17
Sound
Sound Pressure and Sound Pressure Levels .....................................................275
Combining Sound Levels ....................................................................................276
Sound Power and Sound Power Level ...............................................................276
A- and C- Weighting............................................................................................276
Octave bands and 1/3 Octave Bands .................................................................277
Design Guidance for HVAC System Noise .........................................................278
Sound Rating Methods ...............................................................................279–280
Sound Paths in HVAC Systems..........................................................................280
Silencers .............................................................................................................281
Outlet Configurations ..........................................................................................281
Mechanical Equipment Noise Levels ..................................................................282
Mechanical Equipment Sound Isolation..............................................................283
18
Vibration
Single-Degree-of-Freedom Systems ..................................................................284
Two-Degree-of-Freedom Systems......................................................................284
Isolator Selection ........................................................................................285–293
19
HVAC Systems and Equipment
Furnaces .....................................................................................................294–299
Hydronic Heating Units and Radiators........................................................300–305
Unit Ventilators, Unit Heaters, and Makeup Air Units .................................306–318
Small Forced-Air Heating and Cooling Systems.........................................319–326
Unitary Air Conditioners and Heat Pumps ..................................................327–336
Water-Source Heat Pumps .........................................................................337–342
Variable-Refrigerant-Flow Heat Pumps ..............................................................342
Room Air Conditioners and Packaged Terminal Air Conditioners ..............343–347
Evaporative Cooling....................................................................................348–352
20
Automatic Controls
HVAC System Components........................................................................353–359
HVAC Systems ...........................................................................................360–361
21
Occupant Comfort
ASHRAE Standard 55-2010 ...............................................................................362
Graphic Comfort Zone Method ...........................................................................362
Operative and Effective Temperature .................................................................362
Clothing Insulation Values ..........................................................................363–364
Local Discomfort .................................................................................................366
Thermal Comfort in Naturally Ventilated Buildings .............................................367
22
General
System Design Criteria ...............................................................................368–371
Air-Conditioning Formulas ..................................................................................372
Sizing Formulas for Heating/Cooling ..................................................................373
Units and Conversions................................................................................374–375
Appendix: Climatic Design Conditions for Selected Locations...................376–438
Index ..................................................................................................................439–440
vi
PREFACE
The ASHRAE Pocket Guide was developed to serve as a ready, offline reference for engineers without easy access to complete ASHRAE Handbook volumes.
This ninth edition has been revised for 2017 to include updates from current editions of the
ASHRAE Handbook series as well as from various ASHRAE standards. This edition also features a renewed emphasis in basic design aids: content on more specialized system types has
been replaced by an appendix containing climatic design data for selected worldwide locations.
This edition of the ASHRAE Pocket Guide, which was first published in 1987, was compiled by ASHRAE staff editors; previous major contributors were Carl W. MacPhee, Griffith C.
Burr, Jr., Harry E. Rountree, and Frederick H. Kohloss.
Throughout this Pocket Guide, original sources of figures and tables are indicated where
applicable. For space concerns, a shorthand for ASHRAE publications has been adopted.
ASHRAE sources are noted after figure captions or table titles in brackets using the following
abbreviations:
Fig
Tbl
Ch
Std
2017F, 2013F, etc
2016S, 2012S, etc.
2015A, 2011A, etc.
2014R, 2010R, etc.
Figure
Table
Chapter
ASHRAE Standard
ASHRAE Handbook—Fundamentals
ASHRAE Handbook—HVAC Systems and Equipment
ASHRAE Handbook—HVAC Applications
ASHRAE Handbook—Refrigeration
Complete entries for all references cited in tables and figures are available in the original
source publications.
vii
AIR HANDLING AND PSYCHROMETRICS
Figure 1.1
Air Handling and Psychrometrics
1.
Friction Chart for Round Duct ( = 0.075 lbm/ft3 and  = 0.0003 ft)
[2017F, Ch 21, Fig 10]
1
Air Handling and Psychrometrics
Table 1.1
Velocities vs. Velocity Pressures
Velocity V,
fpm
Velocity Pressure Pv ,
in. H2O
300
0.01
400
0.01
500
0.02
600
0.02
700
0.03
800
0.04
900
0.05
1000
0.06
1100
0.08
1200
0.09
1300
0.11
1400
0.12
1500
0.14
1600
0.16
1700
0.18
1800
0.20
1900
0.22
2000
0.25
2100
0.27
2200
0.30
2300
0.33
2400
0.36
2500
0.39
Pv = (V/4005)2
Noncircular Ducts
Hydraulic diameter Dh = 4A/P, where A = duct area (in.2) and P = perimeter (in.). Ducts
having the same hydraulic diameter will have approximately the same fluid resistance at equal
velocities.
Fittings
Resistance to flow through fittings can be expressed by fitting loss coefficients C. The friction loss in a fitting in inches of water is CPv. The more radically the airflow is changed in direction or velocity, the greater the fitting loss coefficient. See ASHRAE Duct Fitting Database for a
complete list. 90° mitered elbows with vanes will usually have C between 0.11 and 0.33.
Round Flexible Ducts
Nonmetallic flexible ducts fully extended have friction losses approximately three times
that of galvanized steel ducts. This rises rapidly for unextended ducts by a correction factor of 4
if 70% extended, 3 if 80% extended, and 2 if 90% extended. For centerline bend radius ratio to
diameter of 1 to 4, the approximate loss coefficient is between 0.82 and 0.87.
2
Duct Leakage Classificationa
Air Handling and Psychrometrics
Table 1.2
Predicted Leakage Class CL
Sealedb,c
Unsealedc
Duct Type
Metal (flexible excluded)
Round and flat oval
Rectangular
 2 in. of water
(both positive and negative pressures)
> 2 and  10 in. of water
(both positive and negative pressures)
Flexible
Metal, aluminum
Nonmetal
3
30
(6 to 70)
12
48
(12 to 110)
48
(12 to 110)c
6
8
12
Fibrous glass
Round
Rectangular
30
(12 to 54)
30
(4 to 54)
3
6
na
na
a
The leakage classes listed in this table are averages based on tests conducted by AISI/
SMACNA (1972), ASHRAE/SMACNA/TIMA (1985), and Swim and Griggs (1995).
The leakage classes listed in the sealed category are based on the assumptions that for
metal ducts, all transverse joints, seams, and openings in the duct wall are sealed at pressures over 3 in. of water, that transverse joints and longitudinal seams are sealed at 2 and 3
in. of water, and that transverse joints are sealed below 2 in. of water. Lower leakage
classes are obtained by careful selection of joints and sealing methods.
c Leakage classes assigned anticipate about 25 joints per 100 linear feet of duct. For systems
with a high fitting to straight duct ratio, greater leakage occurs in both the sealed and
unsealed conditions.
b
Table 1.3
Recommended Ductwork Leakage Class
by Duct Type
Duct Type
Leakage Class CL,
cfm/100 ft2 at 1 in. of water
Metal (flexible excluded)
Round
3
Flat oval
3
Rectangular
Flexible
6
6
Fibrous glass
Round
3
Rectangular
6
Leakage Class CL = Q/PS0.65
where
Q
=
Ps =
(1.1)
leakage rate, cfm/100 ft2 surface area
static pressure difference, inches of water between inside and outside of duct
3
Air Handling and Psychrometrics
Table 1.4
Duct Sealing Requirement Levels
Sealing Requirementsa
Duct Seal Level
A
B
C
a
All transverse joints, longitudinal seams, and duct wall penetrations
All transverse joints and longitudinal seams
Transverse joints only
Transverse joints are connections of two duct or fitting elements oriented perpendicular to flow. Longitudinal seams are joints oriented in the direction of airflow. Duct wall penetrations are openings
made by screws, non-self-sealing fasteners, pipe, tubing, rods, and wire. Round and flat oval spiral
lock seams need not be sealed prior to assembly, but may be coated after assembly to reduce leakage.
All other connections are considered transverse joints, including but not limited to spin-ins, taps and
other branch connections, access door frames, and duct connections to equipment.
Table 1.5
Duct Sealing Recommendations
Recommended Duct Seal Levels
Duct Location
Outdoors
Unconditioned spaces
Conditioned spaces (concealed ductwork)
Conditioned spaces (exposed ductwork)
Table 1.6
Return
A
B
C
B
Duct Leakage per Unit Length
Unsealed Longitudinal Seam Leakage,
Metal Ducts
Type of Duct/Seam
Rectangular
Pittsburgh lock
26 gage
22 gage
Button punch snaplock
26 gage
22 gage
Round
Spiral (26 gage)
Snaplock
Grooved
4
Duct Type
Supply
2 in.
>2 in.
Exhaust
of water
of water
A
A
A
B
A
B
C
B
B
A
A
B
Leakage, cfm per ft Seam Length
at 1 in. Water Pressure
Range
Average
0.01 to 0.02
0.001 to 0.002
0.0164
0.0016
0.03 to 0.15
NA (1 test)
NA (1 test)
0.04 to 0.14
0.11 to 0.18
0.0795
0.0032
0.015
0.11
0.12
Air Handling and Psychrometrics
Figure 1.2
At Exit, the Fitting Coefficient Co Affects t Loss [2017F, Ch 21, Fig 7]
5
Air Handling and Psychrometrics
6
Table 1.7
Lgth.
Adj.b
3.0
4.0
5.0
Lgth.
Adj.b
6
8
10
12
14
16
18
20
24
28
32
36
40
44
48
52
56
60
64
4.0
3.8
4.4
4.9
6
6.6
7.6
8.4
9.1
9.8
10.4
11.0
11.5
12.4
13.2
14.0
14.7
15.3
15.9
16.5
17.1
17.6
18.1
4.5
4.0
4.6
5.2
5.0
4.2
4.9
5.5
5.5
4.4
5.1
5.7
Circular Equivalents of Rectangular Duct for Equal Friction and Capacitya
6.0
4.6
5.3
6.0
7
8
9
10
11
8.2
9.1
9.9
10.8
11.3
11.9
12.6
13.5
14.5
15.3
16.1
16.8
17.5
18.1
18.7
19.3
19.8
20.3
8.7
9.8
10.7
11.4
12.2
12.9
13.5
14.6
15.6
16.5
17.4
18.2
18.9
19.6
20.2
20.9
21.5
22.0
10.4
11.3
12.2
13.0
13.7
14.4
15.6
16.7
17.7
18.6
19.5
20.3
21.0
21.7
22.4
23.0
23.6
10.9
12.0
12.9
13.7
14.5
15.2
16.5
17.7
18.8
19.8
20.7
31.5
22.3
23.1
23.8
24.5
25.1
12.6
13.5
14.4
15.3
16.0
17.4
18.7
19.8
20.9
21.8
22.7
23.6
24.4
25.2
25.9
26.6
Length of One Side of Rectangular Duct (a), in.
6.5
7.0
7.5
8.0
9.0
10.0
4.7
4.9
5.1
5.2
5.5
5.7
5.5
5.7
5.8
6.1
6.4
6.7
6.2
6.4
6.7
6.9
7.3
7.6
Length of One Side of Rectangular Duct (a), in.
12
13
14
15
16
17
18
19
13.1
14.2
15.1
16.0
16.8
18.3
19.6
20.8
21.9
22.9
23.9
24.8
25.7
26.5
27.3
28.0
14.7
15.7
16.7
17.5
19.1
20.5
21.8
22.9
24.0
25.0
26.0
26.9
27.7
28.6
29.3
15.3
16.4
17.3
18.2
19.9
21.3
22.7
23.9
25.0
26.1
27.1
28.0
28.9
29.8
30.6
16.9
17.9
18.9
20.6
22.1
23.5
24.8
26.0
27.1
28.2
29.2
30.1
31.0
31.9
17.5
18.5
19.5
21.3
22.9
24.4
25.7
27.0
28.1
29.2
30.3
31.2
32.2
33.1
19.1
20.1
22.0
23.7
25.2
26.6
27.9
29.1
30.2
31.3
32.3
33.3
34.3
19.7
20.7
22.7
24.4
26.0
27.4
28.8
30.0
31.2
32.3
33.4
34.4
35.4
21.3
23.3
25.1
26.7
28.2
29.6
30.9
32.2
33.3
34.4
35.5
36.5
11.0
6.0
7.0
8.0
12.0
6.2
7.3
8.3
13.0
6.4
7.6
8.6
14.0
6.6
7.8
8.9
15.0
6.8
8.0
9.1
20
22
24
26
28
30
21.9
34.9
25.8
27.5
29.0
30.5
31.8
33.1
34.3
35.4
36.5
37.6
25.1
27.1
28.9
30.5
32.1
33.5
34.9
36.2
37.4
38.5
39.6
26.2
28.3
30.2
32.0
33.6
35.1
36.6
37.9
39.2
40.4
41.6
29.5
31.5
33.3
35.1
36.7
38.2
39.6
41.0
42.3
43.5
30.6
32.7
34.6
36.4
38.1
39.7
41.2
42.7
44.0
45.3
33.9
35.9
37.8
39.5
41.2
42.8
44.3
45.7
47.1
16.0
7.0
8.3
9.4
Lgth.
Adj.b
6
8
10
12
14
16
18
20
24
28
32
36
40
44
48
52
56
60
64
Table 1.7
Lgth.
Adj.b
32
36
40
44
48
52
56
60
64
68
72
76
80
84
88
92
96
a
b
32
35.0
37.1
39.0
40.9
42.6
44.3
45.8
47.3
48.7
50.1
51.4
52.7
53.9
55.1
56.3
57.4
58.4
Circular Equivalents of Rectangular Duct for Equal Friction and Capacitya (Continued)
Length of One Side of Rectangular Duct (a), in.
46
48
50
52
56
60
64
34
36
38
40
42
44
38.2
40.3
42.2
44.0
45.7
47.3
48.9
50.4
51.8
53.2
54.5
55.8
57.0
58.2
59.3
60.5
39.4
41.5
43.5
45.3
47.1
48.8
50.4
51.9
53.4
54.8
56.2
57.5
58.8
60.1
61.3
62.4
42.6
44.7
46.6
48.4
50.2
51.9
53.5
55.0
56.5
57.9
59.3
60.6
61.9
63.1
64.3
43.7
45.8
47.9
49.7
51.6
53.3
54.9
56.5
58.0
59.5
60.9
62.3
63.6
64.9
66.2
48.1
49.1
51.0
52.9
54.7
56.4
58.0
59.6
61.1
62.6
64.0
65.4
66.7
68.0
50.2
52.2
54.2
60.0
57.8
59.4
61.1
62.6
64.1
65.6
67.0
68.4
69.7
51.4
53.4
55.4
57.3
59.1
60.8
62.5
64.1
65.7
67.2
68.7
70.1
71.5
52.5
54.6
56.6
58.6
60.4
62.2
63.9
65.6
67.2
68.7
70.2
71.7
73.1
55.7
57.8
59.8
61.7
63.6
65.3
67.0
68.7
70.3
71.8
73.3
74.8
56.8
59.0
61.0
63.0
64.9
66.7
68.4
70.1
71.7
73.3
74.9
76.3
61.2
63.4
65.4
67.4
69.3
71.1
72.9
74.6
76.3
77.9
79.4
65.6
67.7
69.8
71.8
73.7
75.4
77.3
79.1
80.8
82.4
70.0
72.1
74.2
76.2
78.1
80.0
81.8
83.5
85.3
68
72
76
80
84
74.3
76.5
78.6
80.6
82.5
84.4
86.2
88.0
78.7
80.9
82.9
85.0
86.9
88.8
90.7
83.1
85.2
87.3
89.3
91.3
93.2
87.5
89.6
91.7
93.7
95.7
91.8
94.0
96.1
98.1
Lgth.
Adj.b
32
36
40
44
48
52
56
60
64
68
72
76
80
84
96.2
88
98.4
92
100.5 96
88
Table based on De = 1.30 (ab)0.625/(a + b)0.25
Length of adjacent side of rectangular duct (b), in.
7
Air Handling and Psychrometrics
Air Handling and Psychrometrics
8
Table 1.8
Circular
Duct
Diameter,
in.
5
5.5
6
6.5
7
7.5
8
8.5
9
9.5
10
10.5
11
11.5
12
12.5
13
13.5
14
14.5
15
16
17
18
3
4
5
6
Equivalent Flat Oval Duct Dimensions* [2017F, Ch 21, Tbl 3]
Minor Axis a, in.
7
8
9
10
11
12
14
16
Major Axis A, in.
8
9
11
12
15
19
22
7
9
10
12
13
15
18
20
21
8
10
—
11
13
14
18
19
21
8
9
—
11
12
14
15
17
19
20
23
25
28
30
33
36
39
45
52
59
10
—
12
13
15
16
18
20
21
23
—
—
—
—
—
—
—
* Table based on De = 1.30 (ab)0.625/(a + b)0.25.
10
—
11
13
14
16
17
—
19
21
22
24
27
30
35
39
12
—
14
15
—
17
18
20
22
23
—
—
—
12
—
13
15
16
—
18
19
21
24
27
30
14
—
16
17
—
19
22
24
—
14
—
15
17
18
20
21
25
17
19
22
19
Circular
Duct
Diameter,
in.
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
40
42
44
8
9
10
11
46
50
58
65
71
77
—
—
—
—
—
—
34
38
43
48
52
57
63
70
76
—
—
—
—
—
—
—
—
—
Minor Axis a, in.
12 14 16 18
Major Axis A, in.
28 23 21
31 27 24
34 28 25
37 31 29
42 34 30
45 38 33
50 41 36
56 45 38
59 49 41
65 52 46
72 58 49
78 61 54
81 67 57
71 60
77 66
69
76
79
21
23
26
27
29
32
34
37
40
43
46
49
53
56
59
65
68
71
78
20
26
29
31
34
36
39
40
44
47
51
55
58
61
64
67
77
22
24
35
38
39
42
46
47
50
53
57
60
69
75
82
37
40
41
44
46
49
52
55
62
68
74
Typical Design Velocities for HVAC Components
Duct Element
Louvers
Intake
7000 cfm and greater
Less than 7000 cfm
Exhaust
5000 cfm and greater
Less than 5000 cfm
Filters
Panel filters
Viscous impingement
Dry-type, extended-surface
Flat (low efficiency)
Pleated media (intermediate efficiency)
HEPA
Renewable media filters
Moving-curtain viscous impingement
Moving-curtain dry media
Electronic air cleaners
Ionizing type
Heating Coils
Steam and hot water
Electric
Open wire
Finned tubular
Dehumidifying Coils
Air Washers
Spray type
Cell type
High-velocity spray type
Air Handling and Psychrometrics
Table 1.9
Face Velocity,
fpm
400
See Figure 1.3
500
See Figure 1.3
200 to 800
Duct velocity
Up to 750
250
500
200
150 to 350
500 to 1000
200 min., 1500 max.
Refer to mfg. data
Refer to mfg. data
400 to 500
Refer to mfg. data
Refer to mfg. data
1200 to 1800
9
Air Handling and Psychrometrics
Figure 1.3
10
Criteria for Louver Sizing [2017F, Ch 21, Fig 19]
No.
Dependent Variables
Air Handling and Psychrometrics
Table 1.10 Fan Lawsa,b
For All Fan Laws: t1 = t2 and (point of rating)1 = (point of rating)2
Independent Variables
1a
Q1 = Q2
D 3 N
  ------1-  -------1
N2
 D 2
1b
Pressure1 = Pressure2c
 D 1 2  N 1 2
  -------   -------
 D 2
 N 2
1c
W1 = W2
 D 1 5  N 1 3
  -------   -------
 N 2
 D 2
2a
Q1 = Q2
 D  2  Press.  1/2
  ------1-   ----------------1-
 D 2
 Press. 2
2b
N1 = N2
 D   Press.  1/2
  ------2-   ----------------1-
 D 1  Press. 2
2c
W1 = W2
 D  2  Press.  3/2
  ------1-   ----------------1-
 Press. 2
 D 2
   1/2
  -----2-
  1
3a
N1 = N2
D 3 Q
  ------2-  ------1Q2
 D 1
 
3b
Pressure1 = Pressure2
 D 2 4  Q 1 2
  -------   -------
 D 1
 Q 2
3c
W1 = W2
 D 2 4  Q 1 3
  -------   -------
 Q 2
 D 1
 
1
 -----2
1
 -----2
  2 1/2
  ------
  1
   1/2
  -----2-
  1

 -----12
1
 -----2
a. The subscript 1 denotes that the variable is for the fan under consideration.
b. The subscript 2 denotes that the variable is for the tested fan.
c. Fan total pressure Ptf , fan velocity pressure Pvf , or fan static pressurePsf .
Unless otherwise identified, fan performance data are based on dry air at standard conditions 14.696 psi
and 70°F (0.075 lbm/ft3). In actual applications, the fan may be required to handle air or gas at some
other density. The change in density may be because of temperature, composition of the gas, or altitude.
As indicated by the Fan Laws, the fan performance is affected by gas density. With constant size and
speed, the horsepower and pressure varies directly as the ratio of gas density to the standard air density.
11
Air Handling and Psychrometrics
The application of the Fan Laws for a change in fan speed N for a specific size fan is shown
in Figure 1.4. The computed Pt curve is derived from the base curve. For example, point E(N1 =
650) is computed from point D(N2= 600) as follows:
At D,
Q 2 = 6 cfm and P tf = 1.13 in. of water
2
(1.2)
Using Fan Law 1a at Point E
Q 1 = 6000  650  600  = 6500 cfm
(1.3)
Using Fan Law 1b
P tf
= 1.13   650  600  = 1.33 psi
2
1
(1.4)
The completed P tf , N = 650 curve thus may be generated by computing additional points
1
from data on the base curve, such as point G from point F.
cfm  static pressure, in. of water
hp = ------------------------------------------------------------------------------fan efficiency (decimal)  6356
Figure 1.4
12
Example Calculation of Fan Laws [2016S, Ch 21, Fig 4]
(1.5)
Table 1.11 Types of Fans [2016S, Ch 21, Tbl 1]
Backward-Inclined
Backward-Curved
Centrifugal Fans
Airfoil
Type
Impeller Design
• Blades of airfoil
contour curved away
from direction of
rotation. Deep blades
allow efficient
expansion within
blade passages.
• Air leaves impeller at
velocity less than tip
speed.
• For given duty, has
highest speed of
centrifugal fan
designs.
• Single-thickness
blades curved or
inclined away from
direction of rotation.
• Efficient for same
reasons as airfoil fan.
Housing Design
Performance
Characteristics
Applications
• Scroll design for
• Highest efficiency of
efficient conversion of all centrifugal fan
velocity pressure to
designs and
static pressure.
peak efficiencies occur
• Maximum efficiency
at 50 to 60% of widerequires close
open volume.
clearance and
• Fan has a nonalignment between
overloading
wheel and inlet.
characteristic, which
means power reaches
maximum near peak
efficiency and
becomes lower, or
self-limiting, toward
free delivery.
• Uses same housing
• Similar to airfoil fan,
configuration as airfoil except peak efficiency
design.
slightly
lower.
• Curved blades are
slightly more efficient
than straight blades.
• General heating,
ventilating, and airconditioning
applications.
• Usually only applied
to large systems,
which may be low-,
medium-, or highpressure applications.
• Applied to large,
clean-air industrial
operations for
significant energy
savings.
• Same heating,
ventilating, and airconditioning
applications as airfoil
fan.
• Used in some
industrial applications
where environment
may corrode or erode
airfoil blade.
13
Air Handling and Psychrometrics
Air Handling and Psychrometrics
14
Table 1.11 Types of Fans [2016S, Ch 21, Tbl 1] (Continued)
Centrifugal Fans (continued)
Radial (R)
Radial
Tip (Rt)
Type
Impeller Design
• Higher pressure
characteristics than
airfoil, backwardcurved, and backwardinclined fans.
• Curve may have a
break to left of peak
pressure.
Housing Design
• Scroll similar to and •
often identical to other
centrifugal fan
designs.
• Fit between wheel and •
inlet not as critical as
for airfoil and
backward-inclined
fans.
•
•
Performance
Applications
Characteristics
Higher pressure
• Primarily for materials
characteristics than
handling in industrial
airfoil and
plants. Also for some
backward-curved fans. high-pressure
Pressure may drop
industrial
suddenly at left of
requirements.
peak pressure,
• Rugged wheel is
but this usually causes simple to repair in the
no problems.
field. Wheel
Power rises
sometimes coated with
continually to free
special material.
delivery, which is
• Not common for
an overloading
HVAC applications.
characteristic.
Curved blades are
slightly more efficient
than straight blades.
Table 1.11 Types of Fans [2016S, Ch 21, Tbl 1] (Continued)
Impeller Design
• Flatter pressure curve
and lower peak
efficiency than the
airfoil, backwardcurved, and backwardinclined.
ForwardCurved
Centrifugal Fans (continued)
Type
Housing Design
• Scroll similar to and •
often identical to other
centrifugal fan
designs.
• Fit between wheel and
inlet not as critical as •
for airfoil and
backward-inclined
fans.
•
•
Performance
Applications
Characteristics
Pressure curve less
• Primarily for lowsteep than that of
pressure HVAC
backward-curved fans. applications, such as
Curve dips to left of
residential furnaces,
peak pressure.
central station units,
Highest efficiency
and packaged air
occurs at 40 to 50% of conditioners.
wide-open volume.
Operate fan to right of
peak pressure. Use
caution when selecting
left of peak pressure,
because instability is
possible.
Power rises
continually to free
delivery which is an
overloading
characteristic.
15
Air Handling and Psychrometrics
Air Handling and Psychrometrics
16
Table 1.11 Types of Fans [2016S, Ch 21, Tbl 1] (Continued)
Plenum/
Plug
Propeller
Axial Fans
Centrifugal Fans (continued)
Type
Impeller Design
Housing Design
• Plenum and plug fans
typically use airfoil,
backward inclined, or
backward curved
impellers in a single
inlet configuration.
Relative benefits of
each impeller are the
same as those
described for scroll
housed fans.
• Plenum and plug fans •
are unique in that they
operate with no
housing. The
equivalent of a
housing, or plenum
chamber (dashed line),
depends on the
application.
• The components of the
drive system for the
•
plug fan are located
outside the airstream.
• Low efficiency.
• Limited to lowpressure applications.
• Usually low-cost
impellers have two or
more blades of single
thickness attached to
relatively small hub.
• Primary energy
transfer by velocity
pressure.
• Simple circular ring, •
orifice plate, or
venturi.
• Optimum design is
•
close to blade tips and
forms smooth airfoil
into wheel.
•
Performance
Characteristics
Plenum and plug fans
are similar to
comparable housed
airfoil/backwardcurved fans but are
generally less efficient
because of inefficient
conversion of kinetic
energy in discharge
airstream.
They are more
susceptible to
performance
degradation caused by
poor installation.
High flow rate, but
very low pressure
capabilities.
Maximum efficiency
reached near free
delivery.
Discharge pattern
circular and airstream
swirls.
Applications
• Plenum and plug fans
are used in a variety of
HVAC applications
such as air handlers,
especially where
direct-drive
arrangements are
desirable.
• Other advantages of
these fans are
discharge
configuration
flexibility and
potential for smallerfootprint units.
• For low-pressure,
high-volume airmoving applications,
such as air circulation
in a space or
ventilation through a
wall without
ductwork.
• Used for makeup air
applications.
Table 1.11 Types of Fans [2016S, Ch 21, Tbl 1] (Continued)
Vaneaxial
Axial Fans (continued)
Tubeaxial
Type
Impeller Design
• Somewhat more
efficient and capable
of developing more
useful static pressure
than propeller fan.
• Usually has 4 to 8
blades with airfoil or
single- thickness cross
section.
• Hub is usually less
than half the fan tip
diameter.
• Good blade design
gives medium- to
high-pressure
capability at good
efficiency.
• Most efficient have
airfoil blades.
• Blades may have
fixed, adjustable, or
controllable pitch.
• Hub is usually greater
than half fan tip
diameter.
Performance
Applications
Characteristics
• Cylindrical tube with • High flow rate,
• Low- and mediumclose clearance to
medium pressure
pressure ducted HVAC
blade tips.
capabilities.
applications where air
• Pressure curve dips to distribution
left of peak pressure.
downstream is not
Avoid operating fan in critical.
this region.
• Used in some
• Discharge pattern
industrial applications,
circular and airstream such as drying ovens,
rotates or
paint spray booths,
swirls.
and fume exhausts.
Housing Design
• Cylindrical tube with • High-pressure
close clearance to
characteristics with
blade tips.
medium-volume
• Guide vanes upstream flow capabilities.
or downstream from • Pressure curve dips to
impeller increase
left of peak pressure.
pressure capability
Avoid operating fan in
and efficiency.
this region.
• Guide vanes correct
circular motion
imparted by
impeller and improve
pressure
characteristics and
efficiency of fan.
• General HVAC
systems in low-,
medium-, and highpressure applications
where straight-through
flow and compact
installation are
required.
• Has good downstream
air distribution.
• Used in industrial
applications in place
of tubeaxial fans.
• More compact than
centrifugal fans for
same duty.
17
Air Handling and Psychrometrics
Air Handling and Psychrometrics
18
Table 1.11 Types of Fans [2016S, Ch 21, Tbl 1] (Continued)
Mixed-Flow
MixedFlow
Cross-Flow
Cross-Flow
(Tangential)
Type
Impeller Design
• Combination of axial
and centrifugal
characteristics. Ideally
suited in applications
in which the air has to
flow in or out axially.
Higher pressure
characteristic than
axial fans.
• Impeller with forwardcurved blades. During
rotation the flow of air
passes through part of
the rotor blades into
the rotor. This creates
an area of turbulence
which, working with
the guide system,
deflects the airflow
through another
section of the rotor
into the discharge duct
of the fan casing.
Lowest efficiency of
any type of fan.
Performance
Applications
Characteristics
• The majority of
• Characteristic pressure • Similar HVAC
mixed-flow fans are in curve between axial
applications to
a
fans and centrifugal
centrifugal fans or in
tubular housing and
fans. Higher pressure
applications where an
include outlet turning
than axial fans and
axial fan cannot
vanes.
higher volume flow
generate sufficient
• Can operate without
than centrifugal fans.
pressure rise.
housing or in a pipe
and duct.
• Special designed
• Similar to forward• Low-pressure HVAC
housing for 90°or
curved fans. Power
systems such as fan
straight through
rises continually
heaters, fireplace
airflow.
to free delivery, which inserts, electronic
is an overloading
cooling, and air
characteristic.
curtains.
• Unlike all other fans,
performance curves
include motor
characteristics.
• Lowest efficiency of
any fan type.
Housing Design
Table 1.11 Types of Fans [2016S, Ch 21, Tbl 1] (Continued)
Centrifugal
Other Designs
Power Roof Ventilators
Tubular
Centrifugal
Type
Impeller Design
Housing Design
• Performance similar to
backward-curved fan
except capacity and
pressure are lower.
• Lower efficiency than
backward-curved fan.
• Performance curve
may have a dip to the
left of peak pressure.
• Cylindrical tube
•
similar to vaneaxial
fan,
except clearance to
wheel is not as close. •
• Air discharges radially
from wheel and turns
90° to flow through
•
guide vanes.
• Low-pressure exhaust
systems such as
general factory,
kitchen, warehouse,
and some commercial
installations.
• Provides positive
exhaust ventilation,
which is an advantage
over gravity-type
exhaust units.
• Centrifugal units are
slightly quieter than
axial units.
• Normal housing not •
used, because air discharges from impeller
in full circle.
• Usually does not
include configuration
to recover velocity
pressure component.
Performance
Characteristics
Performance similar to
backward-curved fan,
except capacity and
pressure are lower.
Lower efficiency than
backward-curved fan
because air turns 90°.
Performance curve of
some designs is
similar to axial
flow fan and dips to
left of peak pressure.
Usually operated
without ductwork;
therefore, operates
at very low pressure
and high volume.
Applications
• Primarily for lowpressure, return air
systems in
HVAC applications.
• Has straight-through
flow.
• Centrifugal units are
somewhat quieter than
axial
flow units.
• Low-pressure exhaust
systems, such as
general
factory, kitchen,
warehouse, and some
commercial
installations.
• Low first cost and low
operating cost give an
advantage over
gravity-flow exhaust
systems.
19
Air Handling and Psychrometrics
Air Handling and Psychrometrics
20
Table 1.11 Types of Fans [2016S, Ch 21, Tbl 1] (Continued)
Axial
Other Designs (continued)
Power Roof Ventilators (continued)
Type
Impeller Design
• Low-pressure exhaust
systems such as
general factory,
kitchen, warehouse,
and some commercial
installations.
• Provides positive
exhaust ventilation,
which is an advantage
over gravity-type
exhaust units.
• Hood protects fan
from weather and acts
as safety guard.
Performance
Characteristics
• Essentially a propeller • Usually operated
fan mounted in a
without ductwork;
supporting structure.
therefore, operates
• Air discharges from
at very low pressure
annular space at
and high volume.
bottom
of weather hood.
Housing Design
Applications
• Low-pressure exhaust
systems, such as
general factory,
kitchen, warehouse,
and some commercial
installations.
• Low first cost and low
operating cost give an
advantage over
gravity-flow exhaust
systems.
Figure 1.5
Air Handling and Psychrometrics
Fan System Effect
Deficient Fan/System Performance
Figure 1.5 illustrates deficient fan/system performance. System pressure losses have been
determined accurately, and a fan has been selected for operation at point 1. However, no allowance has been made for the effect of system connections to the fan on fan performance. To compensate, a fan system effect must be added to the calculated system pressure losses to determine
the actual system curve. The point of intersection between the fan performance curve and the
actual system curve is point 4. The actual flow volume is, therefore, deficient by the difference
from 1 to 4. To achieve design flow volume, a fan system effect pressure loss equal to the pressure difference between points 1 and 2 should be added to the calculated system pressure losses,
and the fan should be selected to operate at point 2.
For rated performance, air must enter a fan uniformly over the inlet area in an axial direction
without prerotation.
Fans within plenums and cabinets or next to walls should be located so that air may flow
unobstructed into the inlets.
21
Air Handling and Psychrometrics
Figure 1.6
22
Psychrometric Chart for Normal Temperature, Sea Level [2017F, Ch 1, Fig 1]
Figure 1.7
Direct Expansion or Chilled Water Cooling and Dehumidification
Figure 1.8
Direct Expansion or Chilled Water Cooling and Dehumidification
Air Handling and Psychrometrics
Air-Conditioning Processes
23
Air Handling and Psychrometrics
24
Figure 1.9
Direct Expansion or Chilled Water Cooling and Dehumidification
Figure 1.10
Direct Expansion or Chilled Water Cooling and Dehumidification
Air Handling and Psychrometrics
Figure 1.11
Direct Expansion or Chilled Water Cooling and Dehumidification
Figure 1.12
Direct Expansion or Chilled Water Cooling and Dehumidification
25
Air Handling and Psychrometrics
Table 1.12 Specific Enthalpy of Moist Air
at Standard Atmospheric Pressure, 14.696 psia
[2017F, Ch 1, Tbl 2, Abridged]
Temp.,
°F
–80
–70
–60
–50
–40
–30
–20
–15
–10
–5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
71
72
73
74
75
76
77
78
26
Specific
Enthalpy,
Btu/lbda
–19.213
–16.804
–14.390
–11.966
–9.524
–7.052
–4.527
–3.234
–1.915
–0.561
0.835
2.286
3.803
5.403
7.106
8.934
10.916
13.009
15.232
17.653
20.306
23.229
26.467
30.070
34.097
34.959
35.841
36.744
37.668
38.615
39.584
40.576
41.593
Temp.,
°F
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
110
120
130
140
150
160
170
180
190
200
Specific
Enthalpy,
Btu/lbda
42.634
43.701
44.794
45.914
47.062
48.239
49.445
50.682
51.950
53.250
54.584
55.952
57.355
58.795
60.272
61.787
63.343
64.939
66.578
68.260
69.987
71.761
92.386
119.615
156.077
205.828
275.493
376.736
532.269
793.142
1303.297
2688.145
Altitude, ft
–1000
–500
0
500
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
10,000
15,000
20,000
30,000
Temperature, °F
62.6
60.8
59.0
57.2
55.4
51.9
48.3
44.7
41.2
37.6
34.0
30.5
26.9
23.4
5.5
–12.3
–47.8
Air Handling and Psychrometrics
Table 1.13 Standard Atmospheric Data for Altitudes to 30,000 ft
[2017F, Ch 1, Tbl 1]
Pressure, psia
15.236
14.966
14.696
14.430
14.175
13.664
13.173
12.682
12.230
11.778
11.341
10.914
10.506
10.108
8.296
6.758
4.371
Source: Adapted from NASA (1976).
Table 1.14
Moisture and Air Relationships*
ASHRAE has adopted pounds of moisture per pound of dry air as standard nomenclature.
Relations of other units are expressed below at various dew-point temperatures.
Parts
Grains/
Percent
Equiv.
Lb H2O/
lb dry air
per million
lb dry aira
Moisture%b
Dew Pt. °F
100
0.000001
1
0.0007
—
–80
0.000005
5
0.0035
—
–60
0.000002
21
0.148
0.13
–40
0.000008
79
0.555
0.5
20
0.00026
263
1.84
1.7
10
0.00046
461
3.22
2.9
0
0.0008
787
5.51
5.0
10
0.0013
1315
9.20
8.3
20
0.0022
2152
15.1
13.6
30
0.0032
3154
24.2
21.8
40
0.0052
5213
36.5
33.0
50
0.0077
7658
53.6
48.4
60
0.0111
11080
77.6
70.2
70
0.0158
15820
110.7
100.0
80
0.0223
22330
156.3
—
90
0.0312
31180
218.3
—
100
0.0432
43190
302.3
—
a. 7000 grains = 1 lb
b. Compared to 70°F saturated.
* NUMBERS, 1985, Altadena, CA, by Bill Holladay and Cy Otterholm.
27
Air Handling and Psychrometrics
Space Air Diffusion
Room air diffusion methods can be classified as one of the following:
• Fully mixed systems produce little or no thermal stratification of air within the space.
Overhead air distribution is an example of this type of system.
• Fully (thermally) stratified systems produce little or no mixing of air within the occupied space. Thermal displacement ventilation is an example of this type of system.
• Partially mixed systems provide some mixing within the occupied and/or process
space while creating stratified conditions in the volume above. Most underfloor air distribution and task/ambient conditioning designs are examples of this type of system.
Air distribution systems, such as thermal displacement ventilation (TDV) and underfloor air
distribution (UFAD), that deliver air in cooling mode at or near floor level and return air at or
near ceiling level produce varying amounts of room air stratification. For floor-level supply, thermal plumes that develop over heat sources in the room play a major role in driving overall floorto-ceiling air motion. The amount of stratification in the room is primarily determined by the
balance between total room airflow and heat load. In practice, the actual temperature and concentration profile depends on the combined effects of various factors, but is largely driven by the
characteristics of the room supply airflow and heat load configuration.
28