Solar energy system for heating and domestic hot water supply by means of a heat pump coupled to a photovoltaic ventilated façade

Abstract To spread the nearly Zero Energy Building (NZEB) concept, there is a need for the combined integration of energy saving measures and energy supply systems that minimize the non-renewable primary energy consumption. This paper aims to analyse the capabilities of a novel system composed of a photovoltaic (PV) double skin facade (PV-DSF) coupled to an air source heat pump system (ASHP). The main goal of this system is to provide heating and domestic hot water (DHW) using renewable energy. A quasi-steady mathematical model has been developed to assess the energy capabilities of the proposed system. The thermal and electric generation of the system can be estimated with the hourly outdoor temperature and solar radiation as input data. Calculations have been carried out on an existing block of flats in Bilbao (Spain) to estimate the energy viability of the proposed system. It has been proved that almost all the thermal energy demand can be supplied with the ASHP system, which improves its Seasonal Performance Factor (SPF) in 14.8%. Regarding electric energy, the PV-DSF panels can supply approximately 70% of the electricity consumed by the ASHP system and the fans of the PV-DSF. In addition, if more PV modules are installed on the roof, the demand can be covered with a surplus for other uses. Economically, comparing it with a conventional natural gas boiler facility, the investment cost is amortized in 6.4 years.