2
27-29 $ 2549 ''( )*(
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#
#!$
Utilization of Year Round Integrated Part-Load Energy Consumption
as a Factor for Suitable Chiller Selection
+
,
-
.
(/0 61 3. '+
/)/) 5 10900 ' 02-579-1111 / 1202 0: Chonlathis@gmail.com
Chonlathis Eiamworawutthikul
Department of Mechanical Engineering, Sripatum University
61 Paholyothin Rd, Jatujak District, Bangkok 10900, Thailand Tel 02-579-0111 ext 1202 E-mail: Chonlathis@gmail.com
DE!
)*\]^3]
_\
chiller _```(a`+
) '*a.
``
._\b``_` 1 c _
^. integrated part load value (IPLV) i]a.j`
k/_\ kW/ton an``
chiller o/ -\ (building load)
. -j
a \ *i0 (entering
cooling
water
temperature ECWT) i]/*
a``) (-\3
. /
)*(0
)(q\joj\`````
(a``
)._\ chiller _\
(__\ (
+
- ]
o
]^_\na.
._\b IPLV ``)aq_a\_)3]r/
a`` **_
.
_\ chiller n/*`(as_
_\ IPLV )///(-\3
/(
-\ -_ -``` compressor chiller
Abstract
The study presented in this report investigates the amount of
energy consumption by a chiller used in typical commercial
building by means of year-round integrated part load value. The
method takes into account of the variation of chillerts kW/ton
energy consumption rating due not only to variation of internal &
external heating load of the building but also the changing of
entering cooling water temperature (ECWT) through out the
operating hours of the system according to local weather
condition. The objective of this report is to provide system
designer information to be taken as a factor for more suitable
chiller selection in order to achieve better energy efficient
operation. The results of this investigation indicate that the
utilization of year-round integrated part load value to estimate
total average energy consumption of a chiller is essential for a
designer to better understand behavior of the designed system
and to reduce error in energy usage estimation. The significant
of this method, however, may varied due to the differences in;
local weather condition, share between internal vs. external
heating load of the building, and type of compressor control (i.e.
variable speed or constant speed drive).
1. q`_)(a`xxy(_s_\_
+
)3j_\_``an` (a`
```*_s``an``aa
n (chiller plant) _\`*)3j_\
a chiller *
0r/
_\
chiller /-an
3j /\ )] )a q (a ` / * (
_)oj\ ``_
)._\``(
(`(as((
+
//_\
chiller /*an ( kW/ton) -
\ (building load) .-j
(`\
( a) \*i0 n/
0
_\ chiller 3z
`/
'* )
). /_\ . ``i] q ENETT49-094-2
(--\ .-j
a
`\\*i0(* '*\j)
3jaq`*k_ chiller _\a
_/_\/*an (kW/ton) /a(*
) * ) ./* ) _\ * */_\ chiller _\
*(
+
-_\
*(*
_q)
\-\.-j
a`\/*a
`` * chiller plant ]|)(-a*a
n(j(* . )*_\_`` *]_\
)\ 1 % ``a
``a n c [3, 4] * a .
._\
``an `k-\
(--j `` )_\ ._\
)
a_\_\ chiller *_s
)aq
3]\_))`oj\``oj\o
/*\
*
]_
._\bc
). chiller '*a]3] kW/ton chiller o /*a n i] _/ a n/
).* q
z
`/
'*)_a.*\j
* ))oj\ o / '*b \ j / _\ kW/ton chiller /.-j
a
`\\*i0 i]oj\)a chiller _
\/*_\\j`k //
Hartman [2] 3]r/
_\
chiller ```\*\a (water cool) o/
(*(*an.-j
a`\
\*i0 entering cooling water temperature (ECWT)
*\(* *an chiller ]| )
kW/ton //3] 30-50% ECWT ` 29.4°C
(85°F) 18.9°C (55°F) )
) [1] *\)a
/03]r/
_\ chiller '*,
])n`\ja)
100 *\a]3]
+
ECWT *\o\_(``)a*\ ).3]
+
ECWT /
._\b
chiller plant c _^. integrated part load value (IPLV)
*\(*\_(\
[5] i]/(-
Balimore k Maryland (k
chiller plant _\ chiller `` variable speed drive (3` ECWT *\/a3]
55°F ( 12.8°C) )_\\ chiller plant _\ chiller
``*/)a* ECWT *\ 75°F ( 23.9°C) 3].
28%
)\ j \ /\ …_\ n _\ * a / _\ chiller ))aq/\
).3]
/_\ kW/ton o/ *
an chiller .-j
a`
\\*i0 i]/(-\3
_/
a `` a a .q ._\b_` 1 c _\*\ integrated part
load value `` (a`aq\j_/*(
_)
``_\ chiller (
n / a ._ ^.* i`i\ q/\_`` ) )aq_
|````a n i] )a q / a._^. integrated part load value )]j`^.
(--j
/\3
^. -
chiller _\ *oj\``)]/\
).3])aq
(/a. IPLV ``an/_\
//
*q\j`/\(a`
)._\a.
.b`` IPLV *\/\ )_
*\]^3]
._\ chiller /k _-
+
)-_/\(--j
b
'*a. integrated part load value (IPLV) .
chiller _\/*a_]c '*
).(a`
chiller `\``_\a '*a
0
3]
+
- .-j
a\ condenser entering cooling water
temperature //_\ chiller
- ^./ | / ( -\ ) -
-_ (internal load) - (external load) //
- (--j
\3
.-j
b//
- ```(i0`` constant speed drive (CSD)
variable speed drive (VSD)
2. JD
)) * (0 ] ^_ \ j `/\_ ^.
.- (qualitative) ._\
b (a` chiller /k -_/\(--j
\3
(a`+
) q\j_\oj\``
```3]
)._\a.`` IPLV *
]^)]``_\j`ka chiller
]//*/)a*`*
chiller (-
an* '* chiller ).*an/n
a` 1000 tons (a`-an(j(*
` 900 tons a 8760 '_]c `` |``_\_]^*
ENETT49-094-3
a.a'*_\'(an)j YorkCalc [5] i]
q'oj\_\(3/.0_`` chiller plant _
^./|_\_ aa.
._\
``/*a_` 1 c /
o -\ \ j (-b (weather data) //k ASHRAE /|'
i] 3j `) j \ _/ ' \ j (-3j`qa*` bin /*.-j
\ (dry bulb temperature) bin 5°F q'
.-j
\_/ bin j_/*_` 1 c
)\j.-j
c (wet bulb temperature)
bq'_ 1 c / bin *\3ja*
\_\j*\ /\j*\
(*\_j 1
3000
2500
2000
1500
1000
500
0
Dry B ulb Temperature B in [F]
B angko k
j 1 /\j)' YorkCalc [5]
' YorkCalc _\ Bin Method _.-
\)-- external load
( (
/ 0 . -j ) --_ internal load ( .0xxy) '*(\(+0
(\
`.-j
\ '*a*_\ .-j
(j(*
_\_`` 95°F q/a-an
(j(* 900 tons a*_\-an
\(*` 10% -an(j(* *].-j
\_ bin 20 /a.-j
(j(*i]n. 5°F
(+0
(\ (slope) .-j
` -\
)-)-_ i]3j`'*_\
.-j
(* (weather balance temperature) i]q
.-j
a_\-a\)-`j0 .-j
(*3j/\ 55°F *a*/(\
internal load / -\*)*
`` (+0. -j
-\ `a`` (3.*\*
/(*_j 2 (a`/( internal load 30% _(-
900
Building Load [Tons]
- .-j
a*_``: 95°F Dry Bulb 83 °F
Wet Bulb
- -\_``: 900 tons
- - chiller: 1000 tons centrifugal chiller `` electrical constant speed drive (CSD) variable speed drive (VSD)
- /_\ (Nominal part load energy
consumption): 0.6 kW/ton
- an evaporator: ` 55°F ) 45°F */` 20 ft
- a`\ condenser: \ 85°F 94.4°F */` 20 ft
800
700
External Load
Line
600
500
400
300
200
100
Internal Load
Line
0
5
15 25 35 45 55 65 75 85 95
Dry Bulb Temperature [F]
j 2 /(+0.-j
-\ 30% internal load
' YorkCalc aa.
._\b
IPLV chiller /(+0-a
n\j(-b_` 1 c //(*_j
1 2 '*a\`/_\ kW/ton
Chiller /*an
.-j
a\ Condenser (ECWT) i]o/.-j
)j_ [2, 5] +
` /
_\ kW/ton chiller */ ECWT /a *an *
/_\ chiller ` compressor ``
VSD chiller ` compressor `` CSD
IPLV _\b chiller / /|
/`_\\/\*\_\3*
3. L$MN
_*\a]^``_\
Chiller '*
0``q0in/0//
(%IPLVDIFF) IPLV Chiller (3`.-j
a\
ENETT49-094-4
% IPLV DIFF =
IPLV ECWTMIN = high − IPLV ECWTMIN =low
IPLV ECWTMIN = high
(1)
× 100
'*
IPLVECWTMIN =high
= IPLV chiller )a* ECWTMIN (j
(_ ECWTMIN = 75°F)
IPLVECWT =low = IPLV chiller )a* ECWTMIN /a
MIN
(_ ECWTMIN = 55°F)
a._\(- /^._\
/(-\-_ (internal load)
// 20% 3] 80% -\ *(*_
j 3 '**\``o chiller `` CSD VSD \
_x*
0.80%
0.70%
VSD
0.60%
% IPLV_diff
0.50%
0.40%
CSD
0.30%
0.20%
0.10%
0.00%
0%
20%
40%
60%
80%
100%
% Internal Load
j 3 0in/0// IPLV Chiller )a*
ECWTMIN 75°F )a* 55°F ( %IPLVDIFF /( (1))
oa.*(*_j 3 _\n Chiller )a*.-j
a\ condenser /a(* (ECWTMIN) \ (_
55°F) ) IPLV /a (_\\) '*
// IPLV (3n*\*)](a`
chiller ``` VSD i]_\/(_\*
chilller `` CSD 3].` 2 q/o)
kW/ton chiller `` VSD o/
ECWT chiller `` CSD [2]
%IPLVDIFF chiller \)a*` .-j
a\ condenser // ] (a`
/(-\-_( j]
q
/( internal load (j chiller )a'*b
*an( j _/( internal load /a i] external load \ *an chiller
)o/(--\-
**\
'*\ kW/ton chiller `` CSD `` VSD )
o/.-j
a\ condenser *\*an
\_\ full load )o\/*a
n* *)]q/oa.(* %IPLVDIFF ] %internal load ]
)o*\3]\)``'\ IPLV chiller *\\*) /j```
compressor o/ /(-an
-_ /n/// IPLV *\
\ i]o*\(*\_j 3 %IPLVDIFF (j(*3]
1% i]//)\
[4] %IPLVDIFF 3]
` 30% chillers _^.*`]^_
(a`(-_k Maryland (k
(a`o*\_j 3 %IPLVDIFF \ qo
)
).a.'*_\
(-
i]^.\ (o_\)a'
a chiller .-j
a\ condenser 75°F 55°F \ 798 ' \ 10% 'a
* *)](/*\ .-j
b \3
o/
(as
+
.-j
a\ condenser / _\
chiller
)\(/\/\ .-j
\3
o /
.-j
a\ condenser q.-j
c (wetbulb) b\3
*q\(/ ]^
/
*\a'* %IPLVDIFF /| '
.-j
wet-bulb / \ax(*
(+0 *(*_j 4 '* ). %internal load ` 50% a. %IPLVDIFF q/( (1)
/)a* ECWTMIN chiller 3j_\``
ECWTMIN `.-j
wet-bulb (j(*\3
ECWTMIN ` \.-j
wet-bulb /a(*\3
%IPLVDIFF *\)a.q(* q*\
/\3
50
45
40
% kWh Different
condenser /a(* ( ECWTMIN) *\)a* 75°F ECWTMIN )a* 55°F '* %IPLVDIFF a.'*(
35
30
VSD
25
20
15
CSD
10
5
0
40
50
60
70
80
Average Wet Bulb Temperature [F]
j 4 0in/0// IPLV Chiller )a*
ECWTMIN .-j
wet bulb (j(* /a(* \3
_/|
ENETT49-094-5
)o(*_j 4 (**\*) %IPLVDIFF o/
.-j
Wet-Bulb \3
'*\3
_3`
\i].-j
b wet-bulb /a)_\ %IPLVDIFF (j )
(j3] 40% (a` chiller `` VSD _ .-j
wet-bulb b . 42-45°F ( Chicago _ USA Berlin _ Germany) (a` i] .-j
b
wet-bulb . 76°F %IPLVDIFF . 13% (a`
chiller `` VSD . 5% (a` chiller `` CSD
)o*\(3(*\ (as
+
)
o .-j
a\*i0 /
.-j
_
)./_\ chiller
)](a`\3
(- .-j
wetbulb /a / _\3
.-j
wet-bulb b.
42°F a.
._\ chiller _`]c
'*_\\j kW/ton chiller )oj\o
/ a*_\ ECWT .-j
_`` )a_\*\_\
.b
(j
)
40% 15% (a` chiller `` VSD
CSD /a*` (a`\3
/\.-j
wetbulb b. 75°F *_\
b chiller a*_\ ECWT ``
)3]. 10% (a` chiller `` VSD 5% (a`
chiller `` CSD
\j
/
(a`
*\3ja.(a`
/(-an-_// %internal load
20% 80% '*/|q/*
o
a.3j(*_j 5
15
12.5
% IPLV_diff
10
7.5
5
2.5
0
0%
20%
40%
60%
80%
100%
% Internal Load
j 5 0in/0// IPLV Chiller _(-
)a* ECWTMIN 85°F /a(* 46.5°F
oa._j 5 ` %IPLVDIFF (-
\/* %internal load ).
)`` IPLV a chiller a* ECWT ` 85°F (a*_
``) ` chiller (3` ECWT *\/a.-j
wetbulb /a(* )_\ %IPLVDIFF . 13% (a` chiller
`` VSD . 5% (a` chiller `` CSD
4. P
)*\
03])aq_a_\
b)a_]c a.`` integrated
part load value (IPLV) ``q\j`_
). chiller ((a```ani]
^._\ // ). . ) * _\ q _``/* ]^*\`3]
a.
._\b_`]c chiller
```\*\a -_/\(-a
-\ (building load) . -j
a \ *i0 (ECWT) )(-\3
a.a'*_\'(an)ji]_\ Bin Method _(\
(+0
(\.-j
b_\3
`
-\_`]c
o] ^(3( *\ ) .
._\
b IPLV ``)aq_
\_)3]r/
a`` q\j`
/*(
_)_\ chiller (/_\*\*
]
n / * ` (a s )// /(-
\3
/(-an-_ -
``` compressor chiller variable
speed drive (VSD) constant speed drive (CSD)
0_\n.-j
a\*i0 (ECWT) /.-j
c o/
._\ chiller _` 1 c oa.
(a`(*3]*
IPLV 3] 13% (a` VSD chiller . 5%
(a` CSD chiller a*_\ ECWT `
_\_`` (` 85°F) IPLV chiller )
* ( _\\) (a` chiller (3`
.-j
a\ condenser (ECWT) *\/a '*
_\\)no*)](a`-
/(-\)-_(j] (a`
chiller _\````` VSD )`
.
_\*) chiller (3` ECWT /a*\
)no*)]o/.-j
cb
\3
5. RR
#$
oj\ / ` . ) 0 ] ^ - '*b *. r+0
` (a`aa_````` )0
/
*
Œ (+0 (a`xŽ_\j0
/0
ENETT49-094-6
]^' +,
(.*
,Π0 (
*
Π(a`_]^o
' (*\(as`. . '
/0
) `
^ 0 0*
() )a* (a`
(`(xŽ' YorkCalc (a`_\_]^
!!!
1. Jiratthitijaroen, W., District Cooling Plant: Refrigeration
Plant Simulation, Master of Engineering Thesis, Mechanical
Engineering Department, Faculty of Engineering,
Chulalongkorn University, 2000.
2. Hartman, T., All-Variable Speed Centrifugal Chiller Plants,
ASHRAE Journal, pp. 43-57, September, 2001.
3. Tongshoob, T., and Vitooraporn, C., A Probabilistic
Approach for Cooling Load Calculation, Proceedings of the
19th National Mechanical Engineering Network of Thailand
Conference, Phuket, Thailand, 19-21 October, 2005.
4. Chiller-Plant Energy Performance, HVAC&R Engineering
Update, YORK International, January 1, 1997.
5. YorkCalc Version 7.00.32b , Software Application by
YorkWorks Version : 7.00.FDW , York International Corp.,
1993-98.