ENERGY STAR Qualifying Criteria for Ground Source Heat Pumps

Version 3.1

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Following is the Version 3.1 product specification for ENERGY STAR^®  qualified ground source heat pumps. A product shall meet all of the identified criteria if it is to earn the ENERGY STAR.

Products imported into and sold in Canada must meet all Canadian regulatory and safety requirements.

This technical specification is the same as the product specification published on the U.S. ENERGY STAR Web site and is provided as information only. Administered by Natural Resources Canada’s Office of Energy Efficiency, the ENERGY STAR Program in Canada uses the term Participant to designate companies, organizations and other stakeholders that promote the use of the ENERGY STAR mark on products or in promotional and marketing material and activities. This technical specification was modified to include this change. The use of the term Participant is similar in scope to that of Partner, which is used by the U.S. ENERGY STAR Program.

In order to promote ENERGY STAR qualified Ground Source Heat Pumps in Canada, we encourage manufacturers, retailers and distributors to sign a Participant Administrative Arrangement with Natural Resources Canada to take advantage of promotional and communications opportunities provided by the program.

In order to be marketed and sold as ENERGY STAR, a product must meet all of the identified criteria.

1) Definitions

1. Ground Source Heat Pump
   A ground source heat pump uses the thermal energy of the ground or groundwater to provide residential space conditioning and/or domestic water heating. A ground source heat pump model normally consists of one or more factory-made assemblies that include indoor conditioning and/or domestic water heat exchanger(s), compressors, and a ground-side heat exchanger. A ground source heat pump model may provide space heating, space cooling, domestic water heating, or a combination of these functions and may also include the functions of liquid circulation, thermal storage, air circulation, air cleaning, dehumidifying or humidifying. A ground source heat pump system generally consists of one or more ground source heat pump models, the ground heat exchanger(s), the air and/or hydronic space conditioning distribution system(s), temperature controls, and thermal storage tanks.
    
2. Single-Stage
   Ground source heat pumps that are designed to operate at one stage and one capacity.
    
3. Multi-Stage
   Ground source heat pumps that are designed to operate at more than one stage or capacity through the use of technologies such as multiple stage compressors, dual compressors, variable speed compressors, etc. Multi-stage models are more efficient while running at lower capacities, but have the capability to supply more heating or cooling using higher capacities when required.
    
4. Ground Heat Exchanger
   The method by which heat is exchanged with the ground, groundwater, or surface water. Ground source heat pumps may use any form of ground heat exchange, which includes horizontal, vertical, or submerged surface water closed loops; open loops using ground water, reclaimed water, or surface water; or direct refrigerant-to-ground or refrigerant-to-water heat exchange.
    
5. Closed Loop
   A ground heat exchange method in which the heat transfer fluid is permanently contained in a closed piping system. Also called a ground-loop system.
    
6. Open Loop
   A ground heat exchange method in which the heat transfer fluid is part of a larger environment. The most common open loop systems use ground water, reclaimed water, or surface water as the heat transfer medium. Also called a ground-water system.
    
7. Water-to-Air
   A ground source heat pump model that provides space conditioning primarily by the use of an indoor air heat exchange coil. Water-to-air models may also provide domestic water heating and hydronic space heating by using desuperheater and/or demand water heating functions.
    
8. Water-to-Water
   A ground source heat pump model that provides space conditioning and/or domestic water heating by the use of indoor refrigerant-to-water heat exchanger(s). Water-to- water models may provide domestic water heating by using desuperheater and/or demand water heating functions.
    
9. Direct Geoexchange (DGX)
   A ground source heat pump model in which the refrigerant is circulated in pipes buried in the ground or submerged in water that exchanges heat with the ground, rather than using a secondary heat transfer fluid, such as water or antifreeze solution in a separate closed loop.
    
10. Desuperheater
    A partial heat recovery system that captures heat from the hot refrigerant gas as it leaves the heat pump compressor and transfers it to the domestic hot water. Desuperheaters provide hot water only while the heat pump is providing space conditioning.
     
11. Demand Water Heating
    Demand ground source heat pump water heating models provides for all, or nearly all, of the domestic hot water needs even when space conditioning is not required. This may be accomplished by either stand-alone domestic water heating models or integrated models that use the same compressor for both space conditioning and domestic water heating. This product type is sometimes referred to as a dedicated or full-time water heater.
     
12. Coefficient of Performance (COP)
    A measure of efficiency in the heating mode that represents the ratio of total heating capacity to electrical energy input.
     
13. Energy Efficiency Ratio (EER)
    A measure of efficiency in the cooling mode that represents the ratio of total cooling capacity to electrical energy input.
     
14. Product Family
    A group of models, where the same remote unit is used with several blower coil combinations (horizontal, vertical, A-coil, etc.). The “same remote unit” is defined as the unit with the same compressor and same direct geoexchange heat exchanger.
     

2) Scope

1. Included Products
   Open loop, closed loop, and DGX products that meet the definition of a Ground source Heat Pump as specified herein are eligible for ENERGY STAR qualification, with the exception of products listed in Section 2.B.
    
2. Excluded Products
   Ground source heat pumps intended for commercial use (i.e., 3-phase units) are not eligible for ENERGY STAR.

3) Qualification Criteria

1. Energy Efficiency Requirements

    

   Table 1: Tier 1 Requirements

   Product Type	EER	COP
   Water-to-Air
   Closed Loop Water-to-Air	14.1	3.3
   Open Loop Water-to-Air	16.2	3.6
   Water-to-Water
   Closed Loop Water-to-Water	15.1	3.0
   Open Loop Water-to-Water	19.1	3.4
   DGX
   DGX	15.0	3.5

    

   Table 2: Tier 2 Requirements

   Product Type	EER	COP
   Water-to-Air
   Closed Loop Water-to-Air	16.1	3.5
   Open Loop Water-to-Air	18.2	3.8
   Water-to-Water
   Closed Loop Water-to-Water	15.1	3.0
   Open Loop Water-to-Water	19.1	3.4
   DGX
   DGX	16.0	3.6

    

   Table 3: Tier 3 Requirements

   Product Type	EER	COP
   Water-to-Air
   Closed Loop Water-to-Air	17.1	3.6
   Open Loop Water-to-Air	21.1	4.1
   Water-to-Water
   Closed Loop Water-to-Water	16.1	3.1
   Open Loop Water-to-Water	20.1	3.5
   DGX
   DGX	16.0	3.6

2. Qualifying Multi-Stage Models

   Multi-stage models shall be qualified using the following calculations:

   • EER = (highest rated capacity EER + lowest rated capacity EER) / 2
      
   • COP = (highest rated capacity COP + lowest rated capacity COP) / 2
      
3. Significant Digits and Rounding
   1. All calculations shall be carried out with actual measured or observed values. Only the final result of a calculation shall be rounded. Calculated results shall be rounded to the nearest significant digit as expressed in the corresponding specification limit.
       
   2. Unless otherwise specified, compliance with specification limit shall be evaluated using exact values without any benefit from rounding.

4) Warranty Requirements

Participant shall provide, as standard, a manufacturer limited warranty for its ENERGY STAR qualified ground source heat pump models for all parts and labor for a minimum of two years. The major refrigerant circuit components, including the compressor(s), heat exchanger(s), and expansion and reversing valve(s) shall be warranted for parts and labor for a minimum of five years.

5) Test Requirements

1. Representative Models shall be selected for testing per the following requirements:
   1. For qualification of an individual product model, the representative model shall be equivalent to that which is intended to be marketed and labeled as ENERGY STAR.
       
   2. For qualification of a product family, any model within that product family can be tested and serve as the representative model.
       
2. When testing ground source heat pumps, the following test methods shall be used to determine ENERGY STAR qualification:
    

6) Effective Date

This ENERGY STAR Ground source Heat Pump Specification shall take effect on the dates specified in Table 5, below. To qualify for ENERGY STAR, a product model shall meet the ENERGY STAR specification in effect on the date of manufacture. The date of manufacture is specific to each unit and is the date (e.g., month and year) on which a unit is considered to be completely assembled.

7) Future Specification Revisions

EPA and Natural Resources Canada both reserve the right to change the specification should technological and/or market changes affect its usefulness to consumers, industry, or the environment. In keeping with current policy, revisions to the specification are arrived at through industry discussions. In the event of a specification revision, please note that the ENERGY STAR qualification is not automatically granted for the life of a product model.