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Air to Air Heat Pumps, Split, Multi-split and VRF

1.1           Scope

Air to air heat pumps are products that are specifically designed to transfer heat from the air in one space to the air within another space by means of a refrigeration cycle.

‘Split’ type heat pumps have separate heat collection and rejection units for each space known as ‘outdoor’ and ‘indoor’ units. The ’outdoor’ and ‘indoor’ units are specifically designed to be connected together during installation by refrigerant pipework to form a single functional system.

Variable Refrigerant Flow (VRF) heat pumps are systems specifically designed to automatically adjust the flow of refrigerant to each ‘indoor’ unit so that the heat delivered is matched to its demand. In particular, one of the ‘indoor’ units of a VRF system could be an air curtain.

1.2           Definitions

Air to Air Heat Pumps, Split, Multi-Split and VRF use an electrically operated refrigeration system to transfer heat from air outside a building to the air inside it. They can be used to provide space heating in a wide range of buildings, and some products also are able to provide cooling by reversing the refrigeration flows around the product (these products are also known as reversible ‘air-cooled’ air conditioning units).

Split, multi-split and VRF heat pumps are available with a wide range of efficiencies. The Energy Technology List (ETL) Scheme aims to encourage the purchase of higher efficiency products.

The ETL Scheme covers three categories of products:

1.    Single split (non-VRF) heat pumps that consist of one ‘outdoor’ unit and one ‘indoor’ unit.

2.    Multi-split (non-VRF) heat pumps that consist of one ‘outdoor’ unit connected to two or more ‘indoor’ units using either individual refrigerant circuits (with the indoor units individually controlled) or using a common refrigerant circuit with the indoor units controlled as one.

3.    VRF heat pumps that consist of one ‘outdoor’ unit connected to one or more ‘indoor’ units using a common refrigerant circuit with the indoor units individually controlled.

A heat pump driven air curtain unit for VRF heat pumps may replace one or more ‘indoor’ heat pump units within an ETL eligible VRF heat pump.

Systems with cascade refrigerant/other-medium (e.g. water) heat distribution shall be tested using same methodology as other VRF systems, taking into account all additional energy used in supplementary medium loops, such as circulation pumps’ consumption.

1.3           Requirements

1.3.1       Eligibility requirements

Eligible air to air heat pumps, split, multi-split and VRF shall comply with the requirements as set out below. The individual products do not need to be named on the ETL.

To be eligible, products shall:

  • Consist of an ‘outdoor’ unit and one or more ‘indoor’ units that are:
    • Factory–built sub-assemblies.
    • Supplied as a matched set of units.
    • Designed to be connected together during installation.
  • Incorporate an electrically driven refrigeration system.
  • Be designed for, and include fittings for, permanent installation.
  • Have an appropriate Conformity Assessment mark.

To be eligible, heat pump driven air curtain ‘indoor’ units for multi-split heat pump products shall also:

  • Be specifically designed to be fitted above a doorway or similar opening.
  • Be designed to use electrical air heaters (where fitted) only during defrosting or heat pump failure.

1.3.2       Performance requirements

Eligible products must meet the performance criteria set out in Table 1.1 for:

  • Seasonal Space Heating Energy Efficiency as defined by Ecodesign Commission Regulation (EU) 2016/2281.
  • Seasonal Space Cooling Energy Efficiency as defined by Ecodesign Commission Regulation (EU) 2016/2281.

Products with a rated cooling capacity less than, or equal to, (≤) 12kW shall meet the performance criteria set out in Table 1.1 for:

  • Seasonal Coefficient of Performance (SCOP) across the range of connected capacities.
  • Seasonal Energy Efficiency Ratio (SEER) across the range of connected capacities.

Table 1.1    Performance requirements for air to air heat pumps, split, multi-split and VRF ​​​​​

 

Rated Cooling Capacity

>12 kW

≤12 kW

 
 

Product Category

Heating mode (ηs,h)

Cooling mode (ηs,c)

Heating mode (SCOP)

Cooling mode (SEER)

1 Single split (non-VRF) heat pumps ≥165% ≥250% ≥4.20 ≥6.40
2 Multi-split (non-VRF) heat pumps ≥160% ≥240% ≥4.10 ≥6.30
3 VRF heat pumps ≥170% ≥260% ≥4.30 ≥6.50

“≥” means “greater than or equal to”

In addition, eligible heat pump driven air curtain ‘indoor’ units for multi-split heat pump products shall have an outlet air velocity uniformity (uACU), as defined in Section 5.4.4 of BS ISO 27327-1: 2009, greater than or equal to 70% over the range of doorway/opening heights that they are designed to be fitted above.

1.4           Measurement and Calculations

1.4.1       Energy efficiency metrics

Seasonal Space Heating Energy Efficiency (ηs,h) – ratio between the space heating demand for reference heating season, supplied by a space heater and the annual primary energy consumption required to meet this demand, as defined by Ecodesign Commission Regulation (EU) 2016/2281.

Seasonal Space Cooling Energy Efficiency (ηs,c) – ratio between the space cooling demand for reference cooling season supplied and annual primary energy consumption required to meet that demand, as defined by Ecodesign Commission Regulation (EU) 2016/2281.

Seasonal Coefficient Of Performance (SCOP) – overall coefficient of performance of a heat pump using electricity, representative of the heating season, calculated as the reference annual heating demand divided by annual energy consumption for heating as defined by Commission Regulation (EU) No 206/2012.

Seasonal Energy Efficiency Ratio (SEER) –  ratio of the total cooling capacity to the effective power input of the unit Commission Regulation (EU) No 206/2012.

Primary energy consumption for electricity usage is obtained using Conversion Coefficient (CC), known also as Primary Energy Factor, equal to 2.5, as defined by Ecodesign Commission Regulation (EU) 2016/2281, Annex I.

Reference heating season, also called climate - set of operating conditions describing per bin the combination of outdoor temperatures and the number of hours these temperatures occur for heating for which the unit is declared fit for purpose. There are three reference heating seasons: “A” average, “C” colder and “W” warmer. UK is located in two reference zones: A and W, but for the ETL purposes “A” for average is to be used.

Correction factor (F1) is a correction that accounts for a negative contribution to the seasonal space heating energy efficiency of heaters due to adjusted contributions of temperature controls, equal to 3 % (BS EN 14825:2016).

In case of any changes regarding the value of CC in relevant regulations or test reporting procedures, performance indicators will be calculated using following equations:

(1)   ηs,h= SCOP/CC -F1

(2)   ηs,c= SEER/CC -F1

1.4.2       Test Requirements

No additional testing requirements beyond the measurement standard below.

1.4.3       Measurement standards

Testing for non-VRF products with a cooling capacity greater than 12kW and all VRF products shall be carried out in accordance with the procedures in Ecodesign Commission Regulation (EU) 2016/2281. The standard rating conditions are set out in the Table 1.2 below.

Table 1.2    Test conditions for air to air split, multi-split and VRF heat pumps >12kW ​​​​

 

Product Category

Heating mode (ηs,h)

Cooling mode (ηs,c)

1.

Single split (non VRF) heat pumps

Commission Regulation (EU) No 2281/2016 Annex III, tables 16, 21, 26, average rating conditions 

Commission Regulation (EU) No 2281/2016 Annex III, tables 16, 27, average rating conditions,

2.

Multi-split (non VRF) heat pumps

Commission Regulation (EU) No 2281/2016 Annex III, tables 16, 21, 26, average rating conditions 

Commission Regulation (EU) No 2281/2016 Annex III, tables 16, 27, average rating conditions

3

VRF heat pumps

Commission Regulation (EU) No 2281/2016 Annex III, tables 16, 21, 26, average rating conditions 

Commission Regulation (EU) No 2281/2016 Annex III, tables 16, 27, average rating conditions

Testing products should be carried out in accordance with the procedures in BS EN 14825: 2016 under the test conditions set out in the Table 1.3 below.

Performance data for units with cooling capacity greater than 12 kW should be obtained in accordance with requirements of Commission Regulation (EU) No 2281/2016 Annex III.

Performance data for non-VRF products with a cooling capacity less than or equal to 12kW should be determined following the requirements of Commission Regulation (EU) No 206/2012 Annex II.

Table 1.3    Test conditions for air to air heat pumps split, multi-split and VRF <12kW

 

Product Category

Heating mode (SCOP)

Cooling mode (SEER)

1.

Single, Multi-Split and VRF heat pumps

Commission Regulation (EU) No 206/2012 Annex II, table 1, average rating conditions 

Commission Regulation (EU) No 206/2012 Annex II, table 1

Please note that performance data obtained in accordance with the corresponding procedures and standard rating conditions laid down in BS EN 14825: 2013 will be accepted as an alternative to testing in accordance with BS EN 14825: 2016 until further notice.

1.4.3.1      Calculated results

Where results are determined by calculation then this should be on the basis of design and/or extrapolation from other combinations of indoor and outdoor units. In this case, details of such calculations and/or extrapolations, and of tests to verify the accuracy of the calculations undertaken (including details of the mathematical model for calculating performance of such combinations, and of measurements taken to verify this model) shall be made available. Tests undertaken to verify the accuracy of the calculations must be carried out in accordance with the test procedures described above.

1.4.4       Rounding 

For the avoidance of doubt test data should be presented to 0 decimal places for percentage points in ηsh and ηsc values and to 2 decimal places for SEER and SCOP indicators. As an example, a 20kW air source, single split (non-VRF) heat pump product with a heating mode ηsh of 164.4% would be deemed to be a fail.

1.5           Verification for ETL Listing

This sub-technology is “unlisted” therefore individual products do not need to be listed on the Energy Technology Product List.

1.6           Conformity testing

Products listed on the ETL may be subject to the scheme’s conformity testing programme in order to ensure listed models continue to meet the ETL requirements.

1.7           Review

1.7.1       Indicative review date

The next technical review is scheduled for 2022-23.

1.7.2       Illustrative future direction of the requirements 

Future changes to the Specification may include:

  • Increasing performance thresholds for ηsh, ηch and/or SCOP, SEER.
  • Introduction of refrigerant’s GWP requirements