Assessment of the seasonal energy performance of a multi-function heat pump for domestic hot water preparation in different Italian climates

In this work, the seasonal energy performance of an air-to-water heat pump with condensation heat recovery to prepare Domestic Hot Water (DHW) while simultaneously satisfying the cooling energy needs is investigated numerically with the software TRNSYS 18. A large multi-storey building was considered a case study, and the building energy demand for space cooling and DHW production was calculated for five locations in different regions of Italy to evaluate the influence of climate on the system performance, The results show that adopting a multi-function heat pump allows improving the system Seasonal Performance Factor (SPF) by up to 15% compared to a conventional heat pump with no recovery of the condensation heat since up to 60% of the DHW energy demand can be covered in heat recovery mode. The climate has a strong influence on the applicability of this technology. In locations characterised by a hot summer, the cooling and DHW loads are simultaneous for a large share of the season, and, therefore, the recovery of condensation heat can be maximised.