Experimental exergy analysis of a Ground Source Heat Pump with combi-thermal storage

European climate policies have recognized that the energy communities can play a key role in the energy transition. Indeed, the Clean Energy for all Europeans Package pushes the promotion of renewable-based distributed systems that share electricity produced exclusively from RESs among neighbours connected by electric micro-grids, constituting the so-called Renewable Energy Communities (RECs). In this framework, this paper proposes a techno-economic analysis of a small renewable energy community composed of two office buildings located in Naples (south of Italy). On the roof of each building a rooftop photovoltaic plant (9 kWEl and 14.25 kWEl peak power) is installed and one office is equipped with an electric vehicle. The heating and cooling demands of both offices are satisfied by two reversible air to water heat pumps. Buildings and plants are modelled and simulated by means of TRNSYS 17 simulation software. Each office is able to self-consumed the electricity produced by the photovoltaic plant installed on own roof and to share the surplus electricity with the neighboured office. Thus, an energy, environmental and economic analysis has been carried out to compare the performance of the systems achieved in renewable energy community configuration and from individual buildings in terms of quantity of electricity imported, exported from/to power grid and consumed on-site. The economic analysis has been carried out by considered the current economic support mechanism available in Italy under the transposition of Renewable Energy Directive (RED II) included in the Clean Energy for all Europeans Package. The outcomes evidence that the amount of electricity exported to the grid significantly reduces and the quantity of electricity consumed on-site increases a lot when the buildings are connected within the community. The share of self-consumed photovoltaic electricity rises up to 79% when energy sharing is allowed.