IEA HPP Annex 28 – standardised testing and seasonal performance calculation for multifunctional heat pump systems

Overall energy rating of buildings including installed HVAC systems, as made in the frame of building energy certificates to be introduced in the EU, gets more important on the background of climate protection. Innovative multifunctional system layouts with heat pumps for combined space heating, domestic hot water and further integration of the ventilation system, however, are often not covered by current product test standards and calculation methods. Therefore, Annex 28 in the heat pump program (HPP) of the international energy agency (IEA) has delivered recommendations for comprehensive testing and subsequent performance calculation of residential heat pump systems with combined space- and domestic hot water heating for standardisation organisations. Both testing and performance calculation for combined operating systems are based on existing standards. A first comparison with systems in field monitoring of different types of combined operating heat pumps, including a ventilation compact unit with air-source heat pump, shows deviations between the calculated and monitored seasonal performance in the range of ±6%, approving the feasibility of the method. The recommendations are currently implemented in the frame of the revision of the European heat pump test standards for the domestic hot water testing and calculation standards in the frame of the EU directive on the energy performance of buildings (EPBD).