PROPOSED
STANDARD SAVINGS ESTIMATION PROTOCOL FOR
DAIRY HEAT EXCHANGER
Submitted to
REGIONAL TECHNICAL FORUM
Submitted by
CASCADE ENERGY
5257 NE MLK Jr. Blvd., STE 301
Portland, OR 97211
November 5, 2012
Standard Savings Estimation Protocol - Dairy Heat Exchanger
TABLE OF CONTENTS
1.
PURPOSE ................................................................................................... 1
2.
SUNSET CRITERIA ......................................................................................... 1
3.
DEFINITION
4.
ELIGIBLE PROJECTS ....................................................................................... 2
5.
REQUIRED KNOWLEDGE AND SKILLS OF PRACTITIONER .......................................... 2
6.
REQUIRED DELIVERY VERIFICATION .................................................................. 3
7.
DATA COLLECTION REQUIREMENTS .................................................................. 3
7.1.
7.2.
7.3.
OF KEY TERMS ............................................................................ 1
Required data collection - assumed constant for baseline and post cases............... 4
Required baseline data collection ............................................................................. 4
Required post data collection .................................................................................... 5
8.
PROVISIONAL DATA REQUIREMENTS ................................................................. 6
9.
SAVINGS ESTIMATION STEPS ........................................................................... 6
9.1.
9.2.
9.3.
9.4.
Compressor COP ........................................................................................................ 7
Calculate Baseline Milk Cooling Energy Requirement ............................................... 7
Calculate Post Milk Cooling Energy Requirement ..................................................... 8
Calculate Milk Cooling Energy Saved ......................................................................... 9
10.
SAMPLING PROCEDURE ................................................................................. 9
11.
RELATIONSHIP TO OTHER PROTOCOLS AND GUIDELINES ....................................... 10
12.
TYPICAL COST OF APPLYING THIS PROTOCOL ..................................................... 10
13.
USER’S GUIDE TO THE SAVINGS CALCULATOR .................................................... 11
APPENDIX A ......................................................................................................... 13
COP Sensitivity Analysis .......................................................................................................... 13
R-22 Baseline COP Values ....................................................................................................... 13
R-22 Post COP Values .............................................................................................................. 13
R-404 Baseline COP Values ..................................................................................................... 13
R-404 Post COP Values............................................................................................................ 13
R-507 Baseline COP Values ..................................................................................................... 13
R-507 Post COP Values............................................................................................................ 13
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Standard Savings Estimation Protocol - Dairy Heat Exchanger
1. PURPOSE
This protocol establishes a method by which annual electrical energy savings (kWh/yr) can be estimated
for the installation of a water-to-milk plate and frame heat exchanger to pre-cool milk prior to
mechanical refrigeration.
This protocol specifies the required data and the methodology used to calculate energy savings. Annual
energy savings are computed using the Microsoft Excel-based “Dairy Heat Exchanger Savings Calculator”
that accompanies this document to ensure standardized application of the savings estimation methods.
2. SUNSET CRITERIA
This protocol is approved for use until the Regional Technical Forum commissions another review of the
best available technology for milk pre-cooling, or five years from the approval date of this protocol,
whichever comes first.
3. DEFINITION OF KEY TERMS
Project: One plate and frame heat exchanger installed to cool a specified volume of milk.
Baseline: This modifier refers to the existing mechanical refrigeration system used for milk cooling at
the dairy where the project is being considered.
Post: This descriptor, as in post energy, refers to the period after the project heat exchanger is installed
and operating under normal conditions.
Normal Operating Conditions: The time when the number of cows being milked in a day is between
90% and 110% of the average for the year for that dairy, and the system is in steady-state operation.
Milk Production: The volume of milk (in pounds) that is produced at this dairy in a specified time
period, and that will be cooled as a part of this project.
Coefficient of Performance (COP): A standard method to benchmark the energy efficiency of the
refrigeration compressor that is used to cool the milk after passing through the project heat exchanger.
The COP is defined as the ratio of the cooling provided by the compressor over the electrical energy
consumed by the compressor. It is assumed that the mechanical refrigeration system is the same in
both the baseline and post cases, but that the reduced runtime of the refrigeration compressor (i.e.,
increased cycling) in the post case will reduce the COP in the post case by 5%.
Specific Heat: The amount of heat required to change a unit mass of a substance by one degree in
temperature. By definition, the specific heat of water is equal to 1 BTU/lb-°F. The specific heat of milk is
0.94 BTU/lb-°F.
Heat Exchanger Passes: The number of times a fluid passes through the heat exchanger before exiting.
VFD: Variable Frequency Drive.
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4. ELIGIBLE PROJECTS
The following criteria define the eligible heat exchanger projects.
 The baseline system may include an existing milk-to-water heat exchanger that is being replaced with
a more efficient heat exchanger, if one of the following two criteria can be met:
 The temperature of the milk after the milk-to-water heat exchanger and before the glycol
chiller or other mechanical refrigeration can be directly measured using acceptable
methods listed in Section 7.
 The inlet and outlet water temperature can be measured near the heat exchanger and
the water flow can be measured using acceptable methods listed in Section 7.
 The milk must be cooled in the baseline and post cases from the starting temperature or pre-cooler
outlet temperature to the storage temperature using a glycol chiller and/or other means of
mechanical refrigeration.
 The refrigeration system must use R-22, R-404, or R-507 as a refrigerant.
 The post heat exchanger can be single-pass or multi-pass.
 The post heat exchanger must be of the plate and frame type.
 The post heat exchanger can be new or used.
 The post heat exchanger can be part of a new construction project or a retrofit project.
 The cooling medium used to pre-cool the milk in the post heat exchanger must be water.
 The project may include installing a VFD on the milk transfer pump from the wash tank to the heat
exchanger. No savings are claimed from reduced pumping energy, but the reduced milk flow rate
increases the heat transfer in the heat exchanger.
5. REQUIRED KNOWLEDGE AND SKILLS OF PRACTITIONER
The practitioner responsible for entering data into a savings calculator to develop project-specific
energy savings must possess the following:

This protocol and the accompanying savings calculator.

Understanding of how to use available milk production data and judgment to estimate annual milk
production.

Knowledge of the type of refrigerant used in the refrigeration system.
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The practitioner responsible for applying this protocol to a dairy heat exchanger must possess the
following:

A full understanding of appropriate safety procedures for work involving heat exchangers, pumps,
and the measurement equipment required by this protocol.

Ability to gather spot measurements of fluid temperatures entering and exiting the heat exchanger.
These temperature measurements can be taken from installed temperature gauges, or estimated by
using an infrared thermometer to measure the outside temperature of the un-insulated pipe at the
desired location. If an infrared thermometer is used, the practitioner should understand how
emissivity affects the IR readings, and be able to correctly adjust the emissivity settings as required.

Ability to gather spot measurements of water flow by installing inline flow meters or by using a
bucket and stopwatch. This is only necessary if the practitioner is unable to gather spot
measurements of milk temperature at all necessary points.

Ability to log the duty cycle of the milk transfer pump using a current transducer or induction-based
time-of-use logger.

Ability to verify the refrigerant used in the refrigeration compressor.
6. REQUIRED DELIVERY VERIFICATION
Delivery Verification requires documentation of the following:
 Verification that the installed heat exchanger meets the criteria in Section 4.
 Beginning milk temperature during normal operation.
 Milk temperature between the water-to-milk heat exchanger and the mechanical refrigeration
system during normal operation, if possible.
 Milk storage temperature.
 Annual milk production volume.
 Type of refrigerant.
7. DATA COLLECTION REQUIREMENTS
The following data must be collected and entered into the savings calculator. Data collection is required
during post operation. If a water-cooled heat exchanger exists in the baseline case, data collection is
also required during baseline operation.
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7.1. Required data collection - assumed constant for baseline
and post cases
 Milk Production (mm). The annual total volume of milk (pounds) that passes through the heat
exchanger. This parameter is normally tracked accurately by plant personnel and will be kept in
electronic or paper records.
 Beginning Milk Temperature (Tm-in). The temperature (°F) of the milk entering the heat exchanger.
If
this parameter is not known it is assumed to be 98°F, a typical temperature for fresh milk production.
 Milk Storage Temperature (Tfinal). The temperature (°F) of the milk where it is stored prior to
transportation. This parameter can be read from an installed temperature probe and entered into the
savings calculator, or a default value of 38°F will be used. Research shows this is a very common milk
storage temperature.
 Refrigerant. The calculated COP is a function of the refrigerant used in the mechanical refrigeration
compressor(s) used to cool the milk after passing through the heat exchanger.
7.2. Required baseline data collection
If no water-cooled heat exchanger exists in the baseline case, skip to Section 7.3
7.2.1.
Option A: known milk temperature after precooling
 Exiting Milk Temperature (Tm-out-base). The temperature (°F) of the milk exiting the water-cooled
portion of the heat exchanger, prior to any glycol chiller loop or other mechanical refrigeration. This
temperature should be collected using an installed temperature probe, a temporary temperature
probe, or an infrared thermometer on an exposed section of pipe. If an infrared thermometer is used,
the reading should be calibrated by also measuring the temperature of a similar pipe with a known
temperature fluid, such as the milk inlet pipe to the heat exchanger.
7.2.2.
Option B: unknown milk temperature after precooling
 Entering Water Temperature (Tw-in). The temperature (°F) of the water entering the heat exchanger.
This parameter can be read from an installed temperature probe, or estimated by using an infrared
thermometer to measure the pipe wall temperature into the heat exchanger. If neither of these
methods is possible, this parameter can be estimated from temperature readings at other locations
throughout the facility that use the same water source as the heat exchanger.
 Exiting Water Temperature (Tw-out-baseline). The temperature (°F) of the water exiting the heat
exchanger during normal operating conditions as defined in Section 3. This parameter can be read
from an installed temperature probe, or estimated by using an infrared thermometer to measure the
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pipe wall temperature exiting the heat exchanger. The same method must be used to calculate both
the entering and exiting water temperature in order to obtain a calibrated ΔT.
 Water Flow Rate (mw). The average volumetric flow rate (gallons per minute) of water passing
through the heat exchanger. This parameter can be obtained from the following sources:
Best: Read from an installed and calibrated flowmeter, installed permanently or
temporarily.
Good: Measured by diverting flow into a measurement vessel or bucket of a known volume
and using a stopwatch to measure time.
Fair: Estimated from pipe diameter, pressure readings, and the distance between those
pressure readings, using fluid dynamic equations found in common fluid mechanics
textbooks.
 Milk Transfer Pump Runtime (tpump): The runtime of the pump that transfers milk through the heat
exchanger, in hours, over an uninterrupted period of at least two hours. The milk production during
that exact period must also be known. If milk production is only measured on a daily basis, then the
tpump should be monitored for the entire day. This data collection period does not need to occur
during the collection of other parameters.
 Test Period Milk Production (mtest): The amount of milk produced during the tpump calculation period.
This can be obtained by storage vessel measurements or other types of collection logs.
7.3. Required post data collection
One of the following two options is required.
7.3.1.
Option A: known milk temperature after precooling
 Exiting Milk Temperature (Tm-out-upgrade). The temperature (°F) of the milk exiting the water-cooled
portion of the heat exchanger, prior to any glycol chiller loop or other mechanical refrigeration. This
temperature should be collected using an installed temperature probe, a temporary temperature
probe, or an infrared thermometer on an exposed section of pipe. If an infrared thermometer is used,
the reading should be calibrated by also measuring the temperature of a similar pipe with a known
temperature fluid, such as the milk inlet pipe to the heat exchanger.
7.3.2.
Option B: unknown milk temperature after precooling
 Entering Water Temperature (Tw-in).
Assumed to be equal for baseline and post cases. The
temperature (°F) of the water entering the heat exchanger. This parameter can be read from an
installed temperature probe, or estimated by using an infrared thermometer to measure the pipe
wall temperature into the heat exchanger. If neither of these methods is possible, this parameter can
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be estimated from temperature readings at other locations throughout the facility that use the same
water source as the heat exchanger.
 Exiting Water Temperature (Tw-out-upgrade). The temperature (°F) of the water exiting the heat
exchanger during normal operating conditions as defined in Section 3. This parameter can be read
from an installed temperature probe, or estimated by using an infrared thermometer to measure the
pipe wall temperature into the heat exchanger. The same method must be used to calculate both the
entering and exiting water temperature in order to obtain a calibrated ΔT.
 Water Flow Rate (mw). Assumed to be equal for baseline and upgrade case. The average volumetric
flow rate (gallons per minute) of water passing through the heat exchanger. This parameter can be
obtained from the following sources:
Best: Read from an installed flowmeter, installed permanently or temporarily.
Good: Measured by diverting flow into a measurement vessel or bucket of a known volume
and using a stopwatch to measure time.
Fair: Estimated from pipe diameter, pressure readings, and the distance between those
pressure readings, using fluid dynamic equations found in common fluid mechanics
textbooks.
 Milk Transfer Pump Runtime (tpump). Assumed to be equal for baseline and upgrade case. Heat
transfer from the milk to the water through the heat exchanger can only occur when milk is flowing.
This parameter represents the runtime of the pump that transfers milk though the heat exchanger, in
hours, over an uninterrupted period of at least two hours. The milk production during that exact
period must also be known. If milk production is only measured on a daily basis, then the tpump should
be monitored for the entire day. This data collection period does not need to occur during the
collection of other parameters.
 Test Period Milk Production (mtest). Assumed to be equal for baseline and upgrade case. The amount
of milk produced during the tpump calculation period. This can be obtained by storage vessel
measurements or other types of collection logs.
8. PROVISIONAL DATA REQUIREMENTS
No provisional data requirements.
9. SAVINGS ESTIMATION STEPS
Savings are estimated using the savings calculator that accompanies this protocol. Savings are
estimated as follows:
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Standard Savings Estimation Protocol - Dairy Heat Exchanger
9.1. Compressor COP
 The COP is a function of the suction pressure/saturated temperature, discharge pressure/saturated
temperature, refrigerant, and compressor characteristics. The suction pressure is a function of the
milk storage temperature and the chiller sizing. The discharge pressure is a function of the condenser
sizing, ambient temperature, and the holdback regulator setting (assuming the unit has a holdback
valve). The following assumptions will be applied to simplify the effect of COP on milk chilling
calculations:
 The average suction temperature is assumed to be 20°F below the milk storage
temperature, Tfinal. 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.
 A typical suction temperature is 18°F for dairy refrigeration systems. A typical average
discharge pressure is 200 psig.
 A representative sample of medium temperature Copeland semi-hermetic discus
compressors ratings were averaged for R-22, R-404, and R-507. 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 included in
the Appendix.
 The post COP is assumed to be 5% lower than the baseline COP due to the slight efficiency
penalty incurred by cycling the compressor more often.
9.2. Calculate Baseline Milk Cooling Energy Requirement
 The baseline energy requirement is the electrical energy consumed by the refrigeration system in
order to cool the milk from its initial temperature to its final (storage) temperature.
9.2.1.
Option A: No baseline water-cooled heat exchanger exists, or
milk temperature after pre-cooling is known
 The baseline milk heat load is calculated from the following equation:
𝐸𝑛𝑒𝑟𝑔𝑦𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 [𝐵𝑇𝑈/𝑦𝑟] = 𝑚𝑚 ∗ 𝐶𝑝 ∗ (𝑇𝑚−𝑜𝑢𝑡−𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 − 𝑇𝑓𝑖𝑛𝑎𝑙 ) 𝐸𝑞. (1)
 If no baseline water-cooled heat exchanger exists, then 𝑇𝑚−𝑜𝑢𝑡−𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒
= 𝑇𝑚−𝑖𝑛
 The annual milk production should be known by the practitioner.
 The specific heat of milk is 0.94 BTU/lb-°F.
 Baseline energy (BTU/yr) is converted to electrical energy
by applying the coefficient of performance
of the refrigeration system according to the following equation:
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𝐸𝑛𝑒𝑟𝑔𝑦𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 [𝑘𝑊ℎ/𝑦𝑟] =
𝐸𝑛𝑒𝑟𝑔𝑦𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 [𝐵𝑇𝑈/𝑦𝑟]
𝐶𝑂𝑃 ∗ 3,412
𝐸𝑞. (2)
 The COP for R-22 is 3.20 at a milk storage temperature of 38°F.
The COPs for R-404 and R-507 are
respectively 3.30 and 3.75 at a milk storage temperature of 38°F. All of these values change linearly
with changes to milk storage temperature.
9.2.2.
Option B: Unknown milk temperature after pre-cooling
 The baseline rate of heat removed from the system due to pre-cooling is calculated using the
following equation:
𝑄̇𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 [𝐵𝑇𝑈/ℎ] = 𝑚𝑤 ∗ (𝑇𝑤−𝑜𝑢𝑡−𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 − 𝑇𝑤−𝑖𝑛 ) 𝐸𝑞. (3)
 The annual energy removed from the milk using mechanical refrigeration is calculated using the
following equation:
𝐸𝑛𝑒𝑟𝑔𝑦𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 [𝐵𝑇𝑈/𝑦𝑟]
= 𝑚𝑚 ∗ 𝐶𝑝 ∗ (𝑇𝑚−𝑖𝑛 − 𝑇𝑓𝑖𝑛𝑎𝑙 ) −
𝑄̇𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 ∗ t 𝑝𝑢𝑚𝑝 ∗ 𝑚𝑚
𝑚𝑡𝑒𝑠𝑡
𝐸𝑞. (4)
 The annual milk production (mm) and test period milk production (mtest) must be known by the
practitioner.
 The specific heat of milk is 0.94 BTU/lb-°F.
 Baseline energy (BTU/yr) is converted to electrical energy
by applying the coefficient of performance
of the refrigeration system according to the following equation:
𝐸𝑛𝑒𝑟𝑔𝑦𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 [𝑘𝑊ℎ/𝑦𝑟] =
𝐸𝑛𝑒𝑟𝑔𝑦𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 [𝐵𝑇𝑈/𝑦𝑟]
𝐶𝑂𝑃 ∗ 3,412
𝐸𝑞. (5)
 The COP for R-22 is 3.20 at a milk storage temperature of 38°F.
The COPs for R-404 and R-507 are
respectively 3.30 and 3.75 at a milk storage temperature of 38°F. All of these values change linearly
with changes to milk storage temperature.
9.3. Calculate Post Milk Cooling Energy Requirement
 The post energy requirement is the electrical energy consumed by the refrigeration system in order
to cool the milk from the water-to-milk heat exchanger outlet to its final (storage) temperature.
9.3.1.
Option A: Known milk temperature after pre-cooling
 The post milk heat load is calculated from the following equation:
𝐸𝑛𝑒𝑟𝑔𝑦𝑝𝑜𝑠𝑡 [𝐵𝑇𝑈/𝑦𝑟] = 𝑚 ∗ 𝐶𝑝 ∗ (𝑇𝑚−𝑜𝑢𝑡 − 𝑇𝑓𝑖𝑛𝑎𝑙 ) 𝐸𝑞. (6)
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Standard Savings Estimation Protocol - Dairy Heat Exchanger
 Post energy (BTU/yr) is converted to electrical energy
by applying the coefficient of performance of
the refrigeration system according to the following equation:
𝐸𝑛𝑒𝑟𝑔𝑦𝑝𝑜𝑠𝑡 [𝑘𝑊ℎ/𝑦𝑟] =
9.3.2.
𝐸𝑛𝑒𝑟𝑔𝑦𝑝𝑜𝑠𝑡 [𝐵𝑇𝑈/𝑦𝑟]
𝐶𝑂𝑃 ∗ 3,412
𝐸𝑞. (7)
Option B: Known milk temperature after pre-cooling
 The post rate of heat removed from the system due to pre-cooling is calculated using the following
equation:
𝑄̇𝑢𝑝𝑔𝑟𝑎𝑑𝑒 [𝐵𝑇𝑈/ℎ] = 𝑚𝑤 ∗ (𝑇𝑤−𝑜𝑢𝑡−𝑢𝑝𝑔𝑟𝑎𝑑𝑒 − 𝑇𝑤−𝑖𝑛 ) 𝐸𝑞. (8)
 The annual energy removed from the milk using mechanical refrigeration is calculated using the
following equation:
𝐸𝑛𝑒𝑟𝑔𝑦𝑢𝑝𝑔𝑟𝑎𝑑𝑒 [𝐵𝑇𝑈/𝑦𝑟]
= 𝑚𝑚 ∗ 𝐶𝑝 ∗ (𝑇𝑚−𝑖𝑛 − 𝑇𝑓𝑖𝑛𝑎𝑙 ) −
𝑄̇𝑢𝑝𝑔𝑟𝑎𝑑𝑒 ∗ t 𝑝𝑢𝑚𝑝 ∗ 𝑚𝑚
𝑚𝑡𝑒𝑠𝑡
𝐸𝑞. (9)
 Post energy (BTU/yr) is converted to electrical energy
by applying the coefficient of performance of
the refrigeration system according to the following equation:
𝐸𝑛𝑒𝑟𝑔𝑦𝑝𝑜𝑠𝑡 [𝑘𝑊ℎ/𝑦𝑟] =
𝐸𝑛𝑒𝑟𝑔𝑦𝑝𝑜𝑠𝑡 [𝐵𝑇𝑈/𝑦𝑟]
𝐶𝑂𝑃 ∗ 3,412
𝐸𝑞. (10)
 Post COP is 95% of baseline COP to reflect part load losses.
9.4. Calculate Milk Cooling Energy Saved
 Energy savings (kWh/yr) are calculated by subtracting post energy from baseline energy.
This is the
avoided electrical energy consumption of the refrigeration compressor due to the lower milk heat
load. This does not account for any additional electrical energy required to pump water through the
project heat exchanger, or energy savings due to lower water heating requirements.
10. SAMPLING PROCEDURE
No sampling is allowed. Each project must be analyzed separately using this protocol.
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11. RELATIONSHIP TO OTHER PROTOCOLS AND GUIDELINES
The relationship between this protocol and other relevant protocols and guidelines is as follows:
 International Performance Measurement and Verification Protocol – 2007 (IPMVP), Efficiency
Valuation Organization. This protocol is consistent with Option A - Retrofit Isolation: Key Parameter
Measurement described in the IPMVP, as a number of key parameters are entered or indirectly
assumed.
 M&V Guidelines: Measurement and Verification for Federal Energy Projects Version 3.0, U.S.
Department of Energy Federal Energy Management Program. The relevant parts of this guideline are
principles from Section 11.5 Chillers. This guideline requires both baseline and post measurements,
which is not consistent with this protocol.
12. TYPICAL COST OF APPLYING THIS PROTOCOL
Shown below is an estimate of typical cost of applying this protocol for a single heat exchanger. Projects
that involve more than one heat exchanger at the same facility can multiply these unit costs by the
number of heat exchangers installed.
Category
Equipment
Item
TOTAL
10
$
/Hr
Unit
Cost
Total
Cost
$80
Temperature probe
2
$40
Flow meter
1
$200 $200
Time-of-Use Logger
1
$75
Labor - Practitioner Gather production info
Labor – Technician
Qty/Hours
$75
1
$110
$110
Savings estimate
1
$110
$110
Travel
2
$75
$150
Temperature, flow, and
time-of-use measurements
3
$75
$225
$950
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Standard Savings Estimation Protocol - Dairy Heat Exchanger
13. USER’S GUIDE TO THE SAVINGS CALCULATOR
The Dairy Heat Exchanger Savings Tool calculates the annual energy savings following the steps outlined
in Section 9 of this protocol.
Step 1: Milk Production. Enter the annual milk production (pounds) into the Savings Calculator. This
must be a single number, not a range.
Step 2: Milk Storage Temperature. Enter the average milk temperature in the storage tank
downstream of the project heat exchanger. This is the target temperature of the mechanical
refrigeration system. This must be a single number, not a range. The default temperature is 38°F. If
a number greater than 60 or less than 34 is entered, an error message will appear indicating
“Temperature out of acceptable range.”
Step 3: Beginning Milk Temperature. Enter the average milk temperature as it enters the project heat
exchanger. This must be a single number, not a range. If there is no existing heat exchanger this will
be close to the temperature of the milk as it leaves the cow. The default temperature is 98°F. If a
number greater than 100 or less than 60 is entered, an error message will appear indicating
“Temperature out of acceptable range.”
Step 4: Refrigerant. Select the type of refrigerant used in the refrigeration system from the drop-down
list. The only choices are “R-22”, “R-404”, and “R-507”.
Step 5: Option “A” or “B.” Determine which calculation method will be used. If the project heat
exchanger only uses water as a coolant and temperature measurements can be made on the milk or
milk piping as it exits the heat exchanger, then choose “Option A” and go to Step 6.
If the project heat exchanger uses both water and another coolant and the milk temperature exiting
the water-cooled portion of the heat exchanger is known, then choose “Option A” and go to Step 6.
If the milk temperature exiting the water-cooled portion of the heat exchanger is not known then
choose “Option B” and go to Step 7.
Step 6: Exiting Milk Temperature. If “Option A” was selected in Step 5, enter the milk temperature
exiting the water-cooled portion of the heat exchanger. If there is no existing heat exchanger in the
baseline case, then this temperature should be equal to or close to the beginning milk temperature
entered in Step 3. Go to Step 13.
Step 7: Water Flow. If “Option B” was selected in Step 5, enter the flow rate of water through the
project heat exchanger.
Step 8: Entering Water Temperature. If “Option B” was selected in Step 5, enter the temperature of
the water entering the project heat exchanger.
Step 9: Exiting Water Temperature. If “Option B” was selected in Step 5, enter the temperature of the
water exiting the project heat exchanger.
Cascade Energy
11
Standard Savings Estimation Protocol - Dairy Heat Exchanger
Step 10: Milk Transfer Pump Runtime. If “Option B” was selected in Step 5, enter the number of
logged hours the milk pump operated to transfer a known volume of milk (see Step 11) through the
heat exchanger. This is the amount of time that milk flowed through the pump, not the total elapsed
time of the test period.
Step 11: Test Period Milk Production. If “Option B” was selected in Step 5, enter the volume of milk (in
pounds) that passed through the heat exchanger during the logged milk pump runtime recorded in
Step 10.
Step 12: Water/Milk Flow Ratio. If “Option B” was selected in Step 5, verify that this ratio is between 1
and 3. This is a calculated value; no inputs are required. If this ratio is outside of these parameters,
verify water flow (Step 7), milk pump runtime (Step 10), and milk flow (Step 11).
Step 13: Annual Energy Savings. The Annual Energy Savings in kWh/yr is calculated based on the
inputs from the previous steps. If the Annual Energy Savings displays “ERROR!” verify the inputs are
correct and are within the eligible criteria.
12
Cascade Energy
Standard Savings Estimation Protocol - Dairy Heat Exchanger
APPENDIX A
COP Sensitivity Analysis
R-22 Baseline COP Values
R-22 Post COP Values
R-404 Baseline COP Values
R-404 Post COP Values
R-507 Baseline COP Values
R-507 Post COP Values
Cascade Energy
13
Standard Savings Estimation Protocol - Dairy Heat Exchanger
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%.
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
14
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
15
Standard Savings Estimation Protocol - Dairy Heat Exchanger
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
Table 4: R-22 Baseline and Post COP Values
R-404
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
Table 5: R-404 Baseline and Post COP Values
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
Table 6: R-507 Baseline and Post COP Values
16
Cascade Energy