SUPPORTING DATA FOR STANDARD PROTOCOL FOR
DAIRY HEAT EXCHANGER
Submitted to
REGIONAL TECHNICAL FORUM
Submitted by
CASCADE ENERGY
5257 NE MLK Jr. Blvd., STE 301
Portland, OR 97211
February 20, 2013
Standard Savings Estimation Protocol - Dairy Heat Exchanger
1. ANALYSIS ASSUMPTIONS
Several assumptions were made in the analysis for the use of default values. They are listed below.
Beginning Milk Temperature (Tm-in). Assumed to be 98°F based on industry standard practice of milk temperature production.
Milk Storage Temperature (Tfinal). Assumed to be 38°F based on industry standard practice of refrigerated milk storage temperatures.
Milk Transfer Pump. The heat addition of a milk transfer pump is expected to contribute minimally to the overall temperature of the milk prior
to entering the heat exchanger. No additional heat gain has been accounted for in the savings estimation calculations between the milk
temperature out of the cow to the inlet of the heat exchanger.
Cameron Hydraulics book assumes entire pump efficiency loss turned to heat:
Temp Rise = H(1.0-E)/(778*EU)
Where H = Total head in feet (assume 100ft of lift)
E = Efficiency of the pump (Assume 1hp pump at 65% Efficiency)
U = Specific heat of the pumped liquid in BTU/lb-Deg. F (0.94 BTU/lb-Deg for Milk)
Example: [(100)(1.0-0.65)[ / [(778)(0.65)(0.94)] = 0.07°F temperature rise in fluid
Addition of Milk Transfer Pump VFD. The project may often times include a separate measure of installing a VFD on the milk transfer pump
from the wash tank to the heat exchanger. No additional savings are claimed in the protocol from reduced pumping energy due to the VFD,
however the reduced, and more constant milk flow rate would increase the heat transfer in the heat exchanger. This increase in the heat
transfer may be substantial in some cases. So long as the test period measurement called for in the protocol occurs while the VFD is in operation
during normal operating conditions, these additional savings will be accounted for in the protocol calculation methodology.
http://www.placesense.com/component/docman/doc_view/279-dairy-farm-energy-efficiency
http://asset.sce.com/Documents/Business%20-%20Services%20for%20Your%20Business/CompleteGuide_102005REV.pdf
Cascade Energy
1
Standard Savings Estimation Protocol - Dairy Heat Exchanger
2. COP SENSITIVITY ANALYSIS
The following tables show how much a change in COP affects the predicted energy savings for a given refrigerant, over a wide range of suction
temperatures and discharge pressures. Discharge pressures are shown instead of discharge temperatures because compressor control setpoints
are based on pressure. COP is a function of both suction and discharge temperature/pressure for a given refrigerant in a specific compressor.
For this sensitivity analysis, a nine-term polynomial equation was created to model the changes in COP for a wide range of Copeland mediumtemperature discus compressors under 50 hp, similar to those typically found in dairy refrigeration systems eligible for this project. Each of the
tables below shows the percent difference in energy savings calculated by the dairy heat exchanger tool; this is the difference between the
calculated energy savings at each suction temperature and discharge pressure based on the COP used in this tool versus the calculated energy
savings using the actual COP at that condition. The red indicates an operating parameter that has an error greater than 20%. The green
indicates an operating parameter with an error less than 10%. The suction temperature is assumed to be 18°F and the discharge pressure is 200
psig based off industry standard practice.
R-22
Suction Temperature
12
13
14
15
16
17
18
19
20
21
22
23
24
Discharge Pressure (psig)
160
164
22.0%
20.1%
21.9%
20.0%
21.7%
19.8%
21.6%
19.7%
21.5%
19.6%
21.5%
19.5%
21.4%
19.4%
21.4%
19.4%
21.4%
19.4%
21.4%
19.4%
21.5%
19.4%
21.5%
19.4%
21.6%
19.5%
168
18.2%
18.0%
17.8%
17.7%
17.5%
17.4%
17.4%
17.3%
17.3%
17.3%
17.3%
17.3%
17.3%
172
16.3%
16.0%
15.8%
15.7%
15.5%
15.4%
15.3%
15.2%
15.1%
15.1%
15.1%
15.1%
15.1%
176
14.3%
14.0%
13.8%
13.6%
13.4%
13.3%
13.2%
13.1%
13.0%
12.9%
12.9%
12.9%
12.9%
180
12.3%
12.0%
11.8%
11.5%
11.3%
11.2%
11.0%
10.9%
10.8%
10.7%
10.7%
10.7%
10.6%
184
10.3%
10.0%
9.7%
9.5%
9.2%
9.0%
8.9%
8.7%
8.6%
8.5%
8.4%
8.4%
8.4%
188
8.2%
7.9%
7.6%
7.3%
7.1%
6.9%
6.7%
6.5%
6.4%
6.3%
6.2%
6.1%
6.0%
192
6.2%
5.8%
5.5%
5.2%
4.9%
4.7%
4.5%
4.3%
4.1%
4.0%
3.9%
3.8%
3.7%
196
4.1%
3.7%
3.4%
3.0%
2.8%
2.5%
2.3%
2.0%
1.9%
1.7%
1.5%
1.4%
1.3%
200
2.0%
1.6%
1.2%
0.9%
0.6%
0.3%
0.0%
-0.2%
-0.4%
-0.6%
-0.8%
-0.9%
-1.1%
204
-0.1%
-0.5%
-0.9%
-1.3%
-1.7%
-2.0%
-2.3%
-2.5%
-2.8%
-3.0%
-3.2%
-3.3%
-3.5%
208
-2.2%
-2.7%
-3.1%
-3.5%
-3.9%
-4.2%
-4.5%
-4.8%
-5.1%
-5.3%
-5.5%
-5.7%
-5.9%
212
-4.3%
-4.8%
-5.3%
-5.7%
-6.1%
-6.5%
-6.8%
-7.1%
-7.4%
-7.7%
-7.9%
-8.1%
-8.3%
216
-6.4%
-7.0%
-7.5%
-7.9%
-8.3%
-8.7%
-9.1%
-9.4%
-9.8%
-10.0%
-10.3%
-10.6%
-10.8%
Table 1: R-22 Sensitivity Analysis – Effect of COP on Calculated Energy Savings
2
Cascade Energy
220
-8.6%
-9.1%
-9.6%
-10.1%
-10.6%
-11.0%
-11.4%
-11.8%
-12.1%
-12.4%
-12.7%
-13.0%
-13.2%
224
-10.7%
-11.3%
-11.8%
-12.3%
-12.8%
-13.3%
-13.7%
-14.1%
-14.4%
-14.8%
-15.1%
-15.4%
-15.7%
228
-12.8%
-13.4%
-14.0%
-14.5%
-15.0%
-15.5%
-16.0%
-16.4%
-16.8%
-17.1%
-17.5%
-17.8%
-18.1%
232
-14.9%
-15.6%
-16.2%
-16.7%
-17.3%
-17.8%
-18.2%
-18.7%
-19.1%
-19.5%
-19.9%
-20.2%
-20.5%
236
-17.0%
-17.7%
-18.3%
-18.9%
-19.5%
-20.0%
-20.5%
-21.0%
-21.4%
-21.8%
-22.2%
-22.6%
-22.9%
240
-19.1%
-19.8%
-20.5%
-21.1%
-21.7%
-22.2%
-22.8%
-23.3%
-23.7%
-24.2%
-24.6%
-25.0%
-25.4%
Standard Savings Estimation Protocol - Dairy Heat Exchanger
R-404
Suction Temperature
12
13
14
15
16
17
18
19
20
21
22
23
24
Discharge Pressure (psig)
160
164
18.6%
16.8%
18.7%
16.9%
18.8%
17.0%
19.0%
17.1%
19.1%
17.3%
19.3%
17.4%
19.4%
17.6%
19.6%
17.8%
19.8%
17.9%
20.0%
18.1%
20.1%
18.3%
20.3%
18.5%
20.5%
18.7%
168
14.9%
15.0%
15.1%
15.3%
15.4%
15.6%
15.7%
15.9%
16.1%
16.2%
16.4%
16.6%
16.8%
172
13.0%
13.1%
13.3%
13.4%
13.5%
13.7%
13.8%
14.0%
14.2%
14.4%
14.5%
14.7%
14.9%
176
11.1%
11.2%
11.4%
11.5%
11.6%
11.8%
11.9%
12.1%
12.3%
12.4%
12.6%
12.8%
13.0%
180
9.2%
9.3%
9.4%
9.6%
9.7%
9.8%
10.0%
10.1%
10.3%
10.5%
10.7%
10.9%
11.1%
184
7.3%
7.4%
7.5%
7.6%
7.7%
7.9%
8.0%
8.2%
8.3%
8.5%
8.7%
8.9%
9.1%
188
5.3%
5.4%
5.5%
5.6%
5.7%
5.9%
6.0%
6.2%
6.3%
6.5%
6.7%
6.9%
7.1%
192
3.3%
3.4%
3.5%
3.6%
3.7%
3.9%
4.0%
4.2%
4.3%
4.5%
4.7%
4.9%
5.1%
196
1.2%
1.3%
1.4%
1.5%
1.7%
1.8%
1.9%
2.1%
2.3%
2.4%
2.6%
2.8%
3.0%
200
-0.8%
-0.7%
-0.6%
-0.5%
-0.4%
-0.3%
-0.1%
0.0%
0.2%
0.3%
0.5%
0.7%
0.9%
204
-2.9%
-2.8%
-2.7%
-2.6%
-2.5%
-2.4%
-2.3%
-2.1%
-2.0%
-1.8%
-1.6%
-1.4%
-1.2%
208
-5.0%
-5.0%
-4.9%
-4.8%
-4.7%
-4.5%
-4.4%
-4.3%
-4.1%
-3.9%
-3.8%
-3.6%
-3.4%
212
-7.2%
-7.1%
-7.0%
-7.0%
-6.8%
-6.7%
-6.6%
-6.5%
-6.3%
-6.1%
-6.0%
-5.8%
-5.6%
216
-9.4%
-9.3%
-9.2%
-9.2%
-9.1%
-8.9%
-8.8%
-8.7%
-8.5%
-8.4%
-8.2%
-8.0%
-7.9%
220
-11.6%
-11.6%
-11.5%
-11.4%
-11.3%
-11.2%
-11.1%
-10.9%
-10.8%
-10.6%
-10.5%
-10.3%
-10.1%
224
-13.9%
-13.8%
-13.7%
-13.7%
-13.6%
-13.5%
-13.3%
-13.2%
-13.1%
-12.9%
-12.8%
-12.6%
-12.4%
228
-16.1%
-16.1%
-16.0%
-16.0%
-15.9%
-15.8%
-15.7%
-15.5%
-15.4%
-15.3%
-15.1%
-14.9%
-14.8%
232
-18.5%
-18.4%
-18.4%
-18.3%
-18.2%
-18.1%
-18.0%
-17.9%
-17.8%
-17.6%
-17.5%
-17.3%
-17.1%
236
-20.8%
-20.8%
-20.7%
-20.6%
-20.6%
-20.5%
-20.4%
-20.3%
-20.1%
-20.0%
-19.9%
-19.7%
-19.5%
240
-23.2%
-23.1%
-23.1%
-23.0%
-23.0%
-22.9%
-22.8%
-22.7%
-22.6%
-22.4%
-22.3%
-22.1%
-22.0%
216
-10.9%
-10.6%
-10.2%
-9.8%
-9.5%
-9.1%
-8.7%
-8.3%
-7.9%
-7.5%
-7.0%
-6.6%
-6.2%
220
-13.1%
-12.8%
-12.4%
-12.1%
-11.7%
-11.3%
-10.9%
-10.5%
-10.1%
-9.7%
-9.3%
-8.9%
-8.4%
224
-15.3%
-15.0%
-14.6%
-14.3%
-13.9%
-13.5%
-13.1%
-12.7%
-12.3%
-11.9%
-11.5%
-11.1%
-10.7%
228
-17.5%
-17.2%
-16.8%
-16.5%
-16.1%
-15.8%
-15.4%
-15.0%
-14.6%
-14.2%
-13.8%
-13.3%
-12.9%
232
-19.7%
-19.4%
-19.1%
-18.7%
-18.4%
-18.0%
-17.6%
-17.2%
-16.8%
-16.4%
-16.0%
-15.6%
-15.2%
236
-21.9%
-21.6%
-21.3%
-20.9%
-20.6%
-20.2%
-19.8%
-19.4%
-19.1%
-18.7%
-18.2%
-17.8%
-17.4%
240
-24.1%
-23.8%
-23.5%
-23.2%
-22.8%
-22.4%
-22.1%
-21.7%
-21.3%
-20.9%
-20.5%
-20.1%
-19.7%
Table 2: R-404 Sensitivity Analysis – Effect of COP on Calculated Energy Savings
Suction Temperature
R-507
12
13
14
15
16
17
18
19
20
21
22
23
24
Discharge Pressure (psig)
160
164
19.3%
17.3%
19.7%
17.7%
20.1%
18.1%
20.5%
18.4%
20.9%
18.8%
21.3%
19.2%
21.7%
19.6%
22.1%
20.0%
22.5%
20.4%
22.9%
20.9%
23.3%
21.3%
23.7%
21.7%
24.1%
22.1%
168
15.2%
15.6%
16.0%
16.4%
16.7%
17.1%
17.5%
18.0%
18.4%
18.8%
19.2%
19.6%
20.0%
172
13.1%
13.5%
13.9%
14.2%
14.6%
15.0%
15.4%
15.9%
16.3%
16.7%
17.1%
17.5%
17.9%
176
11.0%
11.3%
11.7%
12.1%
12.5%
12.9%
13.3%
13.7%
14.1%
14.6%
15.0%
15.4%
15.8%
180
8.8%
9.2%
9.6%
10.0%
10.4%
10.8%
11.2%
11.6%
12.0%
12.4%
12.8%
13.3%
13.7%
184
6.7%
7.0%
7.4%
7.8%
8.2%
8.6%
9.0%
9.4%
9.8%
10.2%
10.7%
11.1%
11.5%
188
4.5%
4.9%
5.2%
5.6%
6.0%
6.4%
6.8%
7.2%
7.6%
8.1%
8.5%
8.9%
9.3%
192
2.3%
2.7%
3.0%
3.4%
3.8%
4.2%
4.6%
5.0%
5.4%
5.9%
6.3%
6.7%
7.1%
196
0.1%
0.5%
0.8%
1.2%
1.6%
2.0%
2.4%
2.8%
3.2%
3.7%
4.1%
4.5%
4.9%
200
-2.1%
-1.7%
-1.4%
-1.0%
-0.6%
-0.2%
0.2%
0.6%
1.0%
1.4%
1.9%
2.3%
2.7%
204
-4.3%
-3.9%
-3.6%
-3.2%
-2.8%
-2.4%
-2.0%
-1.6%
-1.2%
-0.8%
-0.4%
0.1%
0.5%
208
-6.5%
-6.2%
-5.8%
-5.4%
-5.0%
-4.6%
-4.2%
-3.8%
-3.4%
-3.0%
-2.6%
-2.2%
-1.7%
212
-8.7%
-8.4%
-8.0%
-7.6%
-7.2%
-6.9%
-6.5%
-6.1%
-5.6%
-5.2%
-4.8%
-4.4%
-4.0%
Table 3: R-507 Sensitivity Analysis – Effect of COP on Calculated Energy Savings
Cascade Energy
3
Standard Savings Estimation Protocol - Dairy Heat Exchanger
3. VARYING REFRIGERANT TYPES
The vast majority of mechanical refrigeration systems at dairies use R-22, R-404 and R-507. In the
protocol, R-22, R-404 and R-507 are assumed to result in the same COP as R-404 based on industry
standard practice. The suction temperature is assumed to be 18°F and the discharge pressure is 200 psig
based off industry standard practice. A representative sample of medium temperature Copeland semihermetic discus compressors ratings were averaged for R-22, R-404, and R-507, which represent most
refrigeration systems found at dairies. The weighted average COP for R-22 was 3.20 at this typical
suction temperature and discharge pressure. The weighted average COPs for R-404 and R-507 were
respectively 3.30 and 3.75 at the same suction and discharge conditions. A sensitivity analysis for these
COP values is referenced above. All refrigerants other than R-22 and R-507 are assumed to result in the
same COP as R-404. Changing the suction temperature by 1°F changes the COP linearly by approximately
0.06 for R-22, and by approximately 0.04 for R-404 and R-507.
R-22
Storage
Tem p
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
42.0
43.0
44.0
Baseline
2.96
3.02
3.08
3.14
3.20
3.26
3.32
3.38
3.44
3.50
3.56
Post
2.81
2.87
2.93
2.98
3.04
3.10
3.15
3.21
3.27
3.33
3.38
R-22 Baseline and Post COP Values
R-404 and Default
Storage
Tem p
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
42.0
43.0
44.0
Baseline
3.06
3.12
3.18
3.24
3.30
3.36
3.42
3.48
3.54
3.60
3.66
Post
2.91
2.96
3.02
3.08
3.14
3.19
3.25
3.31
3.36
3.42
3.48
R-404 Baseline and Post COP Values, also used as default table for other refrigerants
4
Cascade Energy
Standard Savings Estimation Protocol - Dairy Heat Exchanger
R-507
Storage
Tem p
34.0
35.0
36.0
37.0
38.0
39.0
40.0
41.0
42.0
43.0
44.0
Baseline
3.51
3.57
3.63
3.69
3.75
3.81
3.87
3.93
3.99
4.05
4.11
Post
3.33
3.39
3.45
3.51
3.56
3.62
3.68
3.73
3.79
3.85
3.90
R-507 Baseline and Post COP Values
Cascade Energy
5