SRI/USEPA-GHG-VR-34
September 2006
THE ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM
SOUTHERN RESEARCH
INSTITUTE
U.S. Environmental Protection Agency
ETV Joint Verification Statement
TECHNOLOGY TYPE: Ground-Source Heat Pump Water Heating System
APPLICATION: Water Heating
TECHNOLOGY NAME: EarthLinked® Water Heating System
COMPANY: ECR Technologies, Inc.
ADDRESS: 3536 DMG Drive
Lakeland, FL 33811
E-MAIL: info(S>ecrtech.com
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification (ETV) program to facilitate the deployment of innovative or improved environmental
technologies through performance verification and dissemination of information. The goal of the ETV
program is to further environmental protection by accelerating the acceptance and use of improved and
cost-effective technologies. ETV seeks to achieve this goal by providing high-quality, peer-reviewed data
on technology performance to those involved in the purchase, design, distribution, financing, permitting,
and use of environmental technologies
ETV works in partnership with recognized standards and testing organizations, stakeholder groups that
consist of buyers, vendor organizations, and permitters, and with the full participation of individual
technology developers. The program evaluates the performance of technologies by developing test plans
that are responsive to the needs of stakeholders, conducting field or laboratory tests, collecting and
analyzing data, and preparing peer-reviewed reports. All evaluations are conducted in accordance with
rigorous quality assurance protocols to ensure that data of known and adequate quality are generated and
that the results are defensible.
The Greenhouse Gas Technology Center (GHG Center), one of six verification organizations under the
ETV program, is operated by Southern Research Institute in cooperation with EPA's National Risk
Management Research Laboratory. GHG Center stakeholders are particularly interested in building
heating and cooling technologies, including technologies used primarily to heat domestic hot water, with
the potential to improve efficiency and reduce concomitant GHG and criteria pollutant emissions.
The GHG Center collaborated with ECR Technologies, Inc. (ECR) to evaluate their EarthLinked Ground-
Source Heat Pump Water Heating System's performance as installed in a commercial setting. The system
incorporates a ground-sourced heat pump into a building's water heating system. ECR states that the
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EarthLinked system may provide up to 70% reduction in power consumption when compared to electric
water heating systems of equivalent capacity. This reduced energy consumption would also reduce
emissions from the electric power system's generators or natural gas combustion in direct-fired systems.
Broad utilization of such technologies could have a significant beneficial impact on GHG and pollutant
emissions.
TECHNOLOGY DESCRIPTION
The following technology description is based on information provided by ECR and does not represent
verified information. The EarthLinked system typically consists of two or more 50- or 100-foot copper
refrigerant loops (earth loops) installed in the ground, a compressor, a heat exchanger, refrigerant liquid
flow controls, and an active charge control. The earth loops can be installed in horizontal, vertical, or
diagonal configurations. The EarthLinked system circulates non-ozone depleting refrigerant (R-407c)
through the copper earth loops. The manufacturer claims that the system's direct heat transfer from the
earth to the refrigerant is intended to improve heat transfer efficiency.
The liquid refrigerant absorbs heat from the ground, which is typically at a constant temperature year
round (40-80 °F, depending on location), and vaporizes. A compressor raises the refrigerant pressure and
routes it to a heat exchanger. There, the vapor condenses and yields the latent heat of vaporization to
domestic water passing through a heat exchanger and circulating back to the hot water tanks. Refrigerant
is then returned to the earth loops via a patented refrigerant flow control device.
The EarthLinked system consumes power in the compressor and hot water circulation pump, and has no
direct emissions. ECR states that typical EarthLinked heating systems will focus on commercial
applications that require a minimum of 2,000 gallons per day such as restaurants and laundries.
The reader is encouraged to note that this is a heat pump water heater and performance results cannot be
directly compared with those of conventional heating, ventilation, and air conditioning heat pumps.
The test plan defines the EarthLinked heat pump as the device under test (DUT). The DUT and its
integration into the host facility are known as the system under test (SUT).
HOST FACILITY and INSTALLED SYSTEM DESCRIPTION
The Lake Towers Retirement Community, located in Sun City Center, Florida, served as the host facility.
Tests occurred at the Sun Terrace, a one-story building with two residential wings for assisted living.
Each wing has 15 rooms, each with a small vanity sink. Other domestic hot water (DFfW) uses include
two shower rooms, one bathtub, two utility closets, four nurses' stations, and a kitchen.
The system has four 100-ft copper earth loops installed at a depth of 100-ft and in a vertical configuration.
The facility's DFiW source consists of two 15 kilowatt (kW), 480 V electric water heaters operating in
parallel. Each water heater has two electric elements controlled by a single theremostat. One element
port in each heater was removed and is used for the heated water return from the DUT. As hot water at
the site is used, cold city water enters the tanks. ECR claims that the EarthLinked system operates most
efficiently when heating cold water. For this installation, the average return temperature to the heat pump
was 94 °F. Table S-l lists the specifications for the EarthLinked unit installed at the site.
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Table S-l. EarthLinked Specifications
(Source: ECR Technologies, Inc.)
Model Number
Rated Performance
Rated Coefficient of Performance
Heating Capacity
Width
Depth
Height
HC-036-3A
36,000 Btu
3.7
60 gal/hra
24.375"
12.375"
26.5"
a rated at 90 °F water temperature rise
A recirculation pump continuously cycles hot water from Tanks #1 and #2 through the building's DHW
piping and back to the tanks. The circulation loop ensures the immediate availability of hot water at each
tap throughout the facility. Thermal losses due to this loop can be substantial. For the purposes of this
test, thermal losses due to the recirculation loop are considered as part of the total site load.
VERIFICATION DESCRIPTION
A series of short-term tests and a long-term monitoring period were conducted to determine the
performance of the EarthLinked system as compared to the baseline electric resistance-type hot water
heaters.
Short-term testing was conducted on May 26, 2005. Industry-accepted American National Standards
Institute (ANSI) / American Society of Heating, Refrigerating and Air-Conditioning Engineers
(ASHRAE) Type V heat pump water heater test methods formed the basis for the short-term tests.
Short-term test verification parameters were:
• DUT water heating capacity while raising the lowest achievable city water
temperature (likely to be approximately 72 °F in Florida in May) 20 °F or to whatever
temperature can be achieved over a 60-minute period (whichever occurs first), British
thermal units per hour (Btu/h)
• DUT water heating capacity while raising the water temperature from 110 to 130 °F
or over a 60-minute period (whichever occurs first), Btu/h
• DUT coefficient of performance (COP) at the lower and elevated temperatures,
dimensionless
• DUT standby heat loss rate, Btu/h, while operating with the EarthLinked system at
120 ± 5 °F
Long-term monitoring began on May 25, 2006 and continued through July 12, 2006. The goal of the
long-term testing was to characterize the SUT performance in normal daily use. As such, the
ANSI/ASHRAE test method was not valid for long-term testing. The ANSI/ASHRAE method is
performed under controlled conditions over a specific temperature range and does not characterize in-use
operations.
Long-term monitoring results allowed the assessment of:
• difference between SUT electrical power consumption with and without the
EarthLinked system, kW
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• hot water usage and parasitic losses, kW
• operational COP of the DUT, dimensionless
• estimated EarthLinked carbon dioxide (CO2) and oxides of nitrogen (NOX) emission
changes as compared to the baseline electric water heater, Ib/year
• estimated simple cost savings based on the price of electricity saved, $/year
Rationale for the experimental design, determination of verification parameters, detailed testing
procedures, test log forms, and quality assurance/quality control (QA/QC) procedures can be found in the
test and quality assurance plan titled Test and Quality Assurance Plan - ECR Technologies, Inc.
EarthLinked Ground-Source Heat Pump Water Heating System (Southern Research Institute, 2005), and
the addendum to the test plan, titled Addendum to Test and Quality Assurance Plan - ECR Technologies,
Inc. EarthLinked Ground-Source Heat Pump Water Heating System (Southern Research Institute, 2006).
VERIFICATION OF PERFORMANCE
Results of the verification are representative of the EarthLinked system's performance as installed at the
Lake Towers Retirement Community. Quality assurance (QA) oversight of the verification testing was
provided following specifications in the ETV Quality Management Plan. This verification was supported
by an audit of data quality (ADQ) conducted by the GHG Center QA manager. During the ADQ, the QA
manager randomly selected data supporting each of the primary verification parameters and followed the
data through the analysis and data processing system. The ADQ confirmed that no systematic errors were
introduced during data handling and processing.
Short-Term Tests
Short-term tests first measured water heating capacity and COP. Water heating capacity assesses the heat
pump's ability to generate hot water. COP is a dimensionless ratio of water heating energy output to
input energy. The short-term tests consisted of three low temperature and three elevated temperature test
runs, as per the ANSI/ASHRAE test method for Type V water heaters. The system was configured such
that Tank #1 operated on the EarthLinked system and it was completely isolated from the facility's DHW.
The results of the test runs are shown in Table S-2.
Table S-2. Water Heating Capacity and Coefficient of Performance for Short-Term Tests
Runl
Run 2
Run 3
Average
Low Temperature Tests3
Water Heating
Capacity (Btu/h)
35700 ± 1200
3 5000 ±1200
34600 ± 1200
35100 ± 1300
COP
3.61 ±0.12
3.57 ±0.12
3.55 ±0.12
3.58 ±0.12
Elevated Temperature Testsb
Water Heating
Capacity (Btu/h)
32800 ±1100
32300 ±1100
3 1900 ±1100
32300 ±1100
COP
2.78 ±0.10
2.63 ±0.09
2.65 ±0.09
2.69 ±0.10
For the low temperature tests, the average initial tank temperature was 82.1 ± 0.6 °F and the average final tank
temperature was 102.3 ± 0.6 °F
b For the high temperature tests, the average initial tank temperature was 97.6 ± 0.6 °F and the average final tank
temperature was 120.7 ± 0.6 °F
Standby heat loss, a measure of the heat loss rate for the water heater, was also calculated during the
short-term testing. Three standby heat loss test runs were conducted with the system in the same
configuration as for the water heating capacity and COP tests. That is, the heat loss includes the
EarthLinked system, Tank #1, and the connecting pipes. As per the ANSI/ASHRAE test method and the
test plan, data were collected for three complete heating and cooling cycles and were used to calculate
average standby heat loss. The results of the test runs are shown in Table S-3.
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Table S-3. Standby Heat Loss
Cycle 1
Cycle 2
Cycle 3
Average
Heat Loss Rate (Btu/h)
490 ± 90
520 ± 90
450 ± 90
490 ± 90
Table S-3 shows that the average standby heat loss was calculated as 490 ± 90 Btu/h. The high heat loss
indicates that piping in the system may not be adequately insulated.
Long-Term Monitoring
During the long-term monitoring period, the power meter monitored electricity consumption for both
tanks and the DUT. System operators alternated between EarthLinked and resistive element heating on a
weekly schedule. A weekly schedule was chosen because GHG Center personnel predicted that day-to-
day variations in the data would likely follow a weekly pattern. All electric heating elements in both
tanks were disabled when the system was under EarthLinked operation. The thermostats for Tanks #1
and #2 were set to 110 °F during both EarthLinked and resistive element operations. This set point was
required by site management.
Analysts calculated power consumption separately as overall mean real power consumption while
operating from the EarthLinked system and from the heating elements. These measurements were then
normalized in terms of "efficiency" or mean energy consumption over the period divided by mean
thermal energy delivered to the site. The change in normalized electrical power consumption (AZkw) was
calculated by subtracting the mean normalized power consumption for the SUT during the three weeks of
EarthLinked operations (Zkw EarthLmked) from the mean normalized power consumption for both tanks
during the three weeks of resistive element heating (ZkWEiements). Table S-4 summarizes the results.
Table S-4. Electrical Power Consumption
ZkW,EarthLinked (kW)
0.58 ±0.03
ZkW,Elements (kW)
2.33±0.11
AZkW(kW)
1.75 ±0.11
% Difference
75 ± 6%
At this site, the load was substantially below the recommended range for the equipment. Parasitic thermal
losses from the recirculation loop represent 39 ± 8% of the total load.
The average system efficiency (r\) is equal to the average rate of thermal energy delivered to the site loads
divided by the average system input power consumption expressed in common units. The efficiency
provides a measure of the energy delivered to site loads versus the total input energy. It characterizes the
performance of the installation, rather than simply the performance of the DUT by itself. The
improvement in efficiency was calculated as an average improvement comparing the three weeks of
operation using the DUT (r|EarthLinked) to three weeks of operation using the heating elements (r|Eiements).
Table S-5 summarizes these values. The efficiency of the electric elements (rjmements) was expected to be
1.00 and this result was achieved within the confidence limits.
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Table S-5. Average System Efficiency
T|EarthLinked
4.01 ±0.07
^Elements
1.005 ±0.018
At]
3.00 ±0.07
The operational COP of the DUT was also calculated. Operational COP differs from the efficiency
reported in Table S-5. COP looks at the performance of only the DUT and is commonly used to
characterize heat pump technologies. The efficiency characterizes the performance of the whole system
installation, not just the DUT. Operational COP was calculated as the rate of energy delivered by the
DUT to the site (Zkw DUT ) versus the rate of energy consumed by the DUT (Zkw EarthLmked) during actual
operating conditions. This is distinct from the COP measured in the short-term tests. The short-term tests
were performed under controlled conditions for a specific temperature range. This calculation of COP is
performed during actual operating conditions. Table S-6 summarizes the results.
Table S-6. Operational Coefficient of Performance of the DUT
Zkw,Dur(kW)
2.59 ±0.19
ZkW, EarthLinked (kW)
0.58 ±0.03
COP
4.43+0.09, -0.3
The average COP of the DUT during the in-use monitoring was higher than the average COP observed in
the short-term testing (refer to Table S-2). Calculation of COP for the short-term tests was conducted
following the ANSI/ASHRAE tests for Type V heat pump water heaters. Analysts found that this
procedure, however useful for comparison between different pieces of equipment of the same class under
controlled circumstances, may not provide results that are directly representative of in-service operating
conditions. Calculation of COP for the long-term tests was based on the ratio of thermal energy delivered
by the device and the electrical energy consumed by the DUT.
The procedure used for estimating SUT emission reductions correlates the estimated annual electricity
savings in megawatt-hours per year (MWh/year) with Florida and nationwide electric power system
emission rates in pounds per megawatt-hour (Ib/MWh). For this verification, analysts assumed that the
EarthLinked system operates continuously throughout the year with electric power savings as measured
during the long-term monitoring period (refer to Table S-4). Emission data from the EPA's "EGRID"
database were used to estimate state and nationwide emission rates. Table S-7 summarizes the estimated
yearly emission reductions.
Table S-7. Estimated Yearly Emissions Reductions
Pollutant
EREPS,i (Ib/MWh)
MWhDUT,Ann (MWh/year)
Emission Offset (Ib/year)
Florida
CO2
1420.42
NOx
3.36
Nationwide
CO2
1392.49
NOx
2.96
15 ±1
21,700 ±1,400
51±3
21,300 ±1,300
45 ±3
The procedure for estimating SUT simple cost savings is based on the Florida and nationwide prices for retail
electricity at "commercial" rates. Varying prices for retail electricity can be found in many resources. This
methodology of estimating simple cost savings uses the prices found in the Energy Information Agency's
Table 5.6.A. Average Retail Price of Electricity to Ultimate Customers by End-Use Sector, by State. Similar
to emissions reductions, analysts assumed that the EarthLinked system operates continuously throughout the
year with electric power savings as measured during the long-term monitoring period. The EarthLinked
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system does not use auxiliary fuel, nor is it intended as a power source, so their potential costs or revenues are
not considered for this verification. Table S-8 summarizes the estimated yearly cost savings.
Table S-8. Estimated Yearly Cost Savings*
MWhDUT,Ann (MWh/year)
RPeiec (cents/kWh)
Simple Cost Savings (dollars/year)
Florida
Nationwide
15 ±1
9.88
1,500 ±100
9.2
1,410 ±90
* Based on approximately 630 gallons per day average consumption on site. The
intended load for this product is 2,000 gallons per day.
Details on the verification test design, measurement test procedures, and QA/QC procedures can be found in
the test plan, titled Test and Quality Assurance Plan - ECR Technologies, Inc. EarthLinked Ground-Source
Heat Pump Water Heating System (Southern Research Institute 2005), and the test plan addendum, titled
Addendum to Test and Quality Assurance Plan - ECR Technologies, Inc. EarthLinked Ground-Source Heat
Pump Water Heating System (Southern Research Institute 2006). Detailed results of the verification are
presented in the final report, titled Environmental Technology Verification Report for ECR Technologies, Inc.
EarthLinked Ground-Source Heat Pump Water Heating System (Southern Research Institute 2006). Both
can be downloaded from the GHG Center's web-site (www.sri-rtp.com) or the ETV Program web-site
(www.epa.gov/etv).
Signed by Sally Gutierrez 09/27/06 Signed by Richard Adamson 09/20/06
Sally Gutierrez Richard Adamson
Director Director
National Risk Management Research Laboratory Greenhouse Gas Technology Center
Office of Research and Development Southern Research Institute
Notice: GHG Center verifications are based on an evaluation of technology performance under specific,
predetermined criteria and the appropriate quality assurance procedures. The EPA and Southern Research
Institute make no expressed or implied warranties as to the performance of the technology and do not certify
that a technology will always operate at the levels verified. The end user is solely responsible for complying
with any and all applicable Federal, State, and Local requirements. Mention of commercial product names does
not imply endorsement or recommendation.
EPA Review Notice
This report has been peer and administratively reviewed by the U.S. Environmental Protection Agency, and
approved for publication. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
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