scope:

Users of sorption 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. As a measure of the saving to be expected, this guideline provides the calculation basis for the annual heating energy ratios and the annual gas utilisation efficiencies of sorption heat pump systems falling within the scope of this guideline.

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 period of use, 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 sorption heat pump system. Measurements of systems do yield actual consumptions within 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 sorption heat pump system, i. e., of the appliance and the associated peripheral equipment, are therefore particularly important to provide guidance to all parties 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 annual heating energy ratio even under deviating conditions.

The varying, and quite influential, user behaviour being a problem as mentioned above, comparisons to measured energy consumptions can only be made with great reservations.

This guideline applies to mono-energetic adsorption/ absorption heat pump systems for gaseous fuels as per worksheet DVGW G 260, intended for space and DHW heating, up to a maximum fuel input (thermal load) of 70 kW. Heat sources considered are groundwater, earth (borehole heat exchangers (BHE)), air and solar radiation (solar DHW heating, solar backup heating and solar backup for the ambient-heat source). The heat is delivered to a water-based central heating system (heat sink). Gas sorption heat pump systems with additional heater only fall within the scope of this guideline if marketed as one constructional unit where the separate heat-producing appliances cannot be recognised from the outside.