scope:

Users of heat pump systems, and those interested in using them, wish to be clear about the environmentally relevant results to be expected, about energy consumption and heating costs. Governmental and other authorities granting support with the aim of reducing the CO2 emissions and the consumption of primary energy by means of this technology expect realistic statements regarding anticipated savings. This guideline provides the seasonal performance factors of heat generation as necessary input data.

The energy efficiency of heat pumps is determined by quite a number of factors relating particularly to the boundary conditions of operation. In addition to the heat source temperature, the supply temperature of the heating system, and the variations of these quantities over the heating season, the energy consumptions for the auxiliary drives of the heat source systems and the difference between the supply and return temperatures of the heating system are also relevant.

Laboratory measurements of the appliances can only yield accurate information on the energetic benefit if they are related to the design parameters of the entire heat pump system. Measurements of systems do yield actual consumptions depending on the accuracy of measurement, but these results only apply to existing systems already in operation and for which the manner in which the users operate them may well differ. Insufficient results are difficult to explain, and in most cases, cannot subsequently be improved. Easy-to-handle data for correct assessment of the entire heat pump system, i.e., of the appliance and the associated peripherals, is therefore particularly important to provide guidance to all those working in this trade.

The guideline is not meant to replace detailed simulation calculations, nor can it serve as an instruction for dimensioning. However, it allows to make statements on the seasonal performance factor even under deviating conditions

Due to the varying, and quite influential, user behaviour being a significant problem as already mentioned above, a comparison to measured energy consumptions can only be made with reservations.

This guideline applies to electrically driven heat pump systems for space heating and DHW heating up to a useful heat flow up to 100 kW. Heat sources considered are groundwater, ground source (borehole heat exchangers and horizontal ground heat exchangers) and air. The heat is delivered to a water-based central heating system (heat sink).