Hourly dynamic calculation of the primary energy with heat pump generation system (EN 15316-4-2): A case study in Italy

With the aim of reducing greenhouse gas emissions, more and more heat pump generators are being used in the residential space heating sector to replace traditional condensing gas boilers. This paper discusses the application to an Italian case study of the new draft of EN 15316-4-2, which provides a methodology for the calculation of the energy performance of heat pump systems used for domestic hot water preparation or space heating purpose. The case study involves a two-storey residential building equipped with several modulating air-to-water heat pumps. Two different daily profiles for heating were considered: continuous heating mode (heating system on 24 hours a day) and intermittent heating mode. Hourly building energy need for heating, calculated according to EN ISO 52016-1:2017, were used as input. The seasonal coefficient of performance (SCOP) of heat pumps analysed with an intermittent profile are 45.77 % higher on average than those in continuous heating mode, even if, in the intermittent system configuration, there is always an amount of missing energy. Finally, the results show that oversizing the heat pump leads to low SCOP and high non-renewable primary energy; while undersizing the heat pump leads to high SCOP but non-negligible missing energy values.