¶ Hot Water-only Heat Pumps
Where a combination heat pump is present, i.e., the heat pump is providing both space and water heating, follow the guidance in the heat pumps section of the space heating tab here. The guidance in this section relates to heat pumps providing water heating only.
¶ In scope of Ecodesign/ Energy Labelling Directive or with EN16147 data available
If the heat pump is in scope of the Ecodesign and Energy Label Directives or I.S. EN 16147 test data is available, the following methodology is applied.
If heat pump data is imported from the HARP database, this will automatically populate the relevant fields in the DEAP software.
If a heat pump is not on the HARP database, but it has DHW test data compliant with the Ecodesign Product Information requirements or accredited test data to EN16147, that data must be used in DEAP.
The required data from EN16147 test data or Ecodesign technical data or certified EN16147 data is as follows:
- Coefficient of Performance for domestic hot water (CoP) or the water heating energy efficiency (ηwh). The CoP is the term used in EN16147 test reports and is expressed in kW/kW, for example 2.5. The term ηwh is the water heating efficiency displayed on Ecodesign technical data and is expressed as a percentage, for example 100%.
- Reference hot water temperature (⁰C) from EN16147 testing. If there is no appropriate evidence, the default of 40⁰C should be applied.
- Rated Heat Output (kW).
- Declared load profile.
- Standing heat loss of test storage tank (kWh /day) - set as 0 if unknown.
- Volume of DHW accounted for in test (L).
DEAP uses the test data along with system information and hot water demand calculations from the DEAP survey to determine the water heating efficiency and efficiency adjustment factor. DEAP determines if and to what extent a backup water heater is required to meet the dwelling’s water heat requirements when deriving the overall heat pump efficiency.
In the following cases the DEAP software alerts the BER Assessor that some of the data is not in line with requirements of Ecodesign Regulations. In these instances, the BER Assessor should seek the correct data from the client, supplier, or manufacturer. If this is not available, the BER Assessor should inform the client and designer/installer, advising them that the heat pump may not perform to the calculated efficiency:
- Where the volume of DHW accounted for in testing does not meet the requirements in the Ecodesign Regulations
- Where the size of the installed hot water storage in the dwelling is not compatible with the test conditions of the Ecodesign Regulation.
In both instances above, the BER assessor may still use the test data available, but only after seeking revised data as indicated from the supplier/manufacturer.
¶ Hot-water-only Heat Pumps - not in scope of Ecodesign/ Energy Label Directive or EN16147
If the heat pump is not in scope of the Ecodesign and Energy Label Directives or has not been tested to I.S. EN 16147, the following methodology is applied.
It is necessary to determine if the heat pump can meet all of the DHW demand where the Ecodesign Regulations do not apply. Where the heat pump can heat the DHW to the required temperature and does not have an integral immersion or integral electric element capable of providing hot water, the heat pump is assumed to meet all of the DHW demand in DEAP and the guidance here applies. If the heat pump has an integral immersion/element OR cannot heat the stored/supplied DHW to the required temperature, then Section G2.1.1 below applies:
Ability of heat pump to meet temperature:
- As detailed in Section G1.1, the temperature required by the heat pump to meet the DHW requirement is based on the type of installation.
- The maximum flow temperature output from the heat pump is taken from CE marked literature, CE marked data plates or accredited test data for the heat pump in question.
Identifying integral immersion/electric element for water heating
The following rules apply when identifying integral immersion/element for water heating in a heat pump:
- An immersion or water heating electric element is considered to be integral if it is within the heat pump unit and is capable of providing DHW. This would typically be part of the DHW circuit in the heat pump unit or part of a DHW store built into the unit.
- An integral immersion/element must be considered present regardless of whether it is used during normal operation or if it is only provided as a backup to the heat pump.
- An immersion/element is not considered to be integral if it is either absent or is only present in a DHW store physically separate from the heat pump unit.
- Evidence of presence or absence of an integral immersion is taken from product literature, test data, site evidence or a written statement from the system designer/installer for the heat pump make/model and dwelling being assessed.
- If it is not clear if there is an immersion/element integral to the heat pump DHW circuit, assume that it is present.
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DHW heated by heat pump not meeting all DHW demand
This section applies for heat pumps not in scope of the Ecodesign or Energy Labelling Directives or without EN16147 test data and there is an integral immersion/element in the heat pump or the heat pump cannot meet the required DHW temperatures detailed above. The water heating efficiency and water heating efficiency adjustment factor in DEAP are set out below and are automatically derived by DEAP.
Where the heat pump does not meet all of the DHW demand and EN14511-2/ EN255-2 or Table 4a default data is used as the basis for the DHW efficiency, DEAP assumes that 50% of DHW is heated by the heat pump and 50% by an immersion heater. The heat pump water heating efficiency is adjusted by DEAP as follows:
- SPF is the seasonal performance factor of the heat pump entered by the user in DEAP as determined by one of the following methods and is entered in kW/kW units (e.g., 320% would be 3.2):
- EN 14511-2 (from HARP or certified test data averaged from test points in DEAP Appendix G).
- EN 255-2 (from HARP or certified test data test data averaged test points in DEAP Appendix G).
- Table 4a default in DEAP manual.
- The water heating efficiency adjustment factor is set to 1 by DEAP in this case.
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DHW efficiency in DEAP based on EN 255-3
Where the heat pump has been tested to EN255-3 and this is used as the basis for the DHW efficiency, DEAP bases the proportion of domestic hot water provided by the heat pump on the ’Reference hot water temperature‘ from the EN 255-3 test certificate and calculates the remaining portion to be provided by the backup water heater. The efficiency for water heating is calculated based on the COP of the heat pump to EN 255-3 and the fraction of hot water provided by the backup heater (if present) and the corresponding efficiency of the backup heater. Key data entries are as follows:
- COP (in kW/kW rather than as a percentage) is taken directly from EN255-3 certified data and entered by the user in DEAP.
- The reference hot water temperature (OC) and heating capacity are entered in DEAP. Where reference hot water temperature is unknown, default it to 40OC.
- DEAP calculates the overall efficiency based on the requirement for backup heater as the efficiency of main water heating system.
- The water heating efficiency adjustment factor is set to 1 by DEAP.
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DHW heated by heat pump meeting all DHW demand
This section applies for heat pumps not in scope of the Ecodesign or Energy Labelling Directive or EN16147 test data where there is no integral immersion/element in the heat pump and the heat pump meets the required DHW temperatures detailed above. The water heating efficiency and adjustment factor in DEAP are set out below.
Where the heat pump meets all of the DHW demand and EN14511-2 or EN255-2 are used as the basis for the DHW efficiency, it is assumed that all of the DHW is heated by the heat pump:
- SPF is the seasonal performance factor of the heat pump entered by the user is determined from one of the following methods
- EN 14511 -2 (from HARP or certified test data averaged from test points in DEAP Appendix G)
- EN 255-2 (from HARP or certified test data averaged from test points in DEAP Appendix G)
- DEAP sets the efficiency adjustment factor to 0.7.
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DHW heated by immersion only
Where an immersion heater is used for heating all hot water, the main water heater is specified as an immersion as per Table 4a.