VDI 4650 Blatt 1:2009-03

Space heating contributes to energy consumption to a large degree. In addition to a cutback on the demand by means of thermal insulation, heating technology offers a considerable potential for reducing energy consumption. In particular, the socalled thermodynamic heating using heat pumps can lead to significant savings in new, but also in existing buildings by making use of the ambient heat resulting from solar radiation, and of geothermal heat. Heat-pump heating is currently one of the best possibilities of using solar energy in Central European climate. This VDI guideline describes an easy, yet sufficiently exact, method for the calculation of the energy efficiency, which takes into account all influence quantities of technical relevance. 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).