[BLDG-SIM] DOE2.1e HP HEAT-EIR-FPLR Problems
Xiaobing Liu
XLiu at climatemaster.com
Wed Apr 4 09:23:06 PDT 2007
Chris:
In your message and data, It seems there are some misunderstandings about the EIR-FPLR used in the DOE-2 program. For heat pump application, which adjusts heating/cooling output by turning on and off the compressor, the value of EIR-FPLR is the actual heat pump run time during a hour. The definition of PLR is the ratio of heating/cooling demand to the heating/cooling capacity of the heat pump during a particular hour. In other word, PLR is the ideal heat pump run time without considering any cycling loss. Therefore, when PLR drops, the value of EIR-FPLR will also drop. Due to the cycling loss, the value of EIR-FPLR is usually larger than the PLR, which means the heat pump has to run a little longer to offset the cycling loss when providing required heating/cooling. The cycling loss of the heat pump can be determined from its Cycling Degradation factor (Cd), which is usually available from heat pump manufacturers.
BTW, If the fan power has been accounted for in the COP and the indoor fan of the heat pump will run continuously, you'd better subtract the effect of fan power when you converting COP to EIR. Otherwise, you may overestimate the fan energy consumption if you also specify a non-zero fan power in the simulation since you count the fan power twice by doing so.
Hope it helps,
Xiaobing
-----Original Message-----
From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com]On Behalf Of Chris Jones
Sent: Wednesday, April 04, 2007 9:42 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] DOE2.1e HP HEAT-EIR-FPLR Problems
I am comparing the default DOE2.1e HP heating curves to the
performance data from various manufacturers. In particular the
EIR-FPLR curve does not fit what the manufacturers show in their
data. The default curve shows the EIR dropping as the part load
ratio drops. My assumption is that PLR = Operating Capacity/Design
Capacity. With the Trane, McQuay, and Waterfurnace data, the EIR
increases as the PLR goes down. I am assuming that part load is a
result of lower flow through the unit or from higher entering dry bulb
temperature. So when I do create my set of heating curves
HEAT-EIR-FT, HEAT-CAP-FT and HEAT-EIR-FPLR, the performance is
significantly worse than with the default DOE2.1e curves.
Am I misinterpreting how to plot the data points for the HEAT-EIR-FPLR
curve? Example from Trane:
COP CAP
EIR
Ent
DB Ent
WT PLR
EIR/EIR
Design GPM
FPLR
4.2 112000
0.238 68
68
1.000
1.000
24.5
(1.000, 1.000)
3.1 62675
0.323
70
20
0.560
1.355
12.1
(0.560, 1.355)
3.1 64639
0.323
70
20
0.577
1.355
18.4
(0.577, 1.355)
3.2 65641
0.313
70
20
0.586
1.313
24.4
(0.586, 1.313)
3.3 71123
0.303
70
30
0.635
1.273
12.1
(0.635, 1.273)
3.4 73541
0.294
70
30
0.657
1.235
18.4
(0.657, 1.235)
3.4 74631
0.294
70
30
0.666
1.235
24.4
(0.666, 1.235)
3.5 79943
0.286
70
40
0.714
1.200
12.1
(0.714, 1.200)
3.6 82643
0.278
70
40
0.738
1.167
18.4
(0.738, 1.167)
3.6 83991
0.278
70
40
0.750
1.167
24.4
(0.750, 1.167)
3.7 88881
0.270
70
50
0.794
1.135
12.1
(0.794, 1.135)
3.8 91903
0.263
70
50
0.821
1.105
18.4
(0.821, 1.105)
3.9 93457
0.256
70
50
0.834
1.077
24.4
(0.834, 1.077)
4 98031
0.250
70
60
0.875
1.050
12.1
(0.875, 1.050)
4 101429
0.250 70
60
0.906
1.050
18.4
(0.906, 1.050)
4.1 103173
0.244 70
60
0.921
1.024
24.4
(0.921, 1.024)
4.2 107353
0.238 70
70
0.959
1.000
12.1
(0.959, 1.000)
4.2 111199
0.238 70
70
0.993
1.000
18.4
(0.993, 1.000)
4.3 113135
0.233 70
70
1.010
0.977
24.4
(1.010, 0.977)
4.4 116795
0.227 70
80
1.043
0.955
12.1
(1.043, 0.955)
4.4 121041
0.227 70
80
1.081
0.955
18.4
(1.081, 0.955)
4.5 123169
0.222 70
80
1.100
0.933
24.4
(1.100, 0.933)
4.5 126363
0.222 70
90
1.128
0.933
12.1
(1.128, 0.933)
4.6 130957
0.217 70
90
1.169
0.913
18.4
(1.169, 0.913)
4.7 133313
0.213 70
90
1.190
0.894
24.4
(1.190, 0.894)
Thanks for any help!
Chris Jones, P.Eng.
14 Oneida Avenue
Toronto, ON M5J2E3
Tel. 416 203-7465
Fax. 416 946-1005
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