Domestic Annual Heat Pump System Efficiency DAHPSE
Domestic Annual Heat Pump System Efficiency (DAHPSE) was developed by bre to show the annual efficiency of a heat pump in a similar way to the use of SEDBUK for boilers, to account for elements that are missing from other efficiency assessments allowing for better comparisons of different actual products.
Whilst there are a number of ways to calculate the efficiency of a system such as Coefficient of Performance (COP), Seasonal Coefficient of Performance (SCOP) or Seasonal Performance Factor (SPF) they all have varying degrees of accuracy. For example COP is limited when considering efficiency throughout a whole year, both COP and SCOP exclude dwelling heat losses, the impact of avereaged climate data, and hot water operation, heating hours, heat pump cycles and so on. Whilst on the other hand whilst SPF allows greater flexibility for the inclusion or exclusion of various aspecst depending on the boundaries considered (SPF1-4) they often don't for example include the impact auxiliary components such back-up direct-electric heaters or circulation pumps.
Heat Pump (HP) Compliance for the Building Regulations Part F for dwellings is carried our through SAP (Standard Assessment Procedure) the UK’s National Calculation Methodology for the energy rating of dwellings based on annual energy. The revised SAP calculation method for Heat Pumps (also developed by bre) is based on the Ecodesign HP test data (EN14825 and EN16147) and the EN15316-4-2 calculation method. The test data requirements and SAP HP calculation is published in CALCM:01 assessing the annual energy consumption for space and hot water including these auxiliary components such as pumps and backup heating.
The intention of DAHPSE is to provide a route to estimate and compare the annual efficiency of real heat pumps, in the full real, if you like situation of use scenario. The bre DAHPSE estimator is on online tool that helps to show DAHPSE for any heat pump system that is listed in the bre Product Characteristics Database (PCDB).
For further information see related articles and under each of the secttions bre DAHPSE beta Efficiency estimator, bre DAHPSE beta Background, bre DAHPSE beta Dwelling heat loss and bre DAHPSE beta Hot water consumption
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