Solar thermal and ground source absorption heat pump: Energy analysis for a nearly Zero Energy Building

The retrofitting of an existing gymnasium building located in Northern Italy is simulated by TRNSYS-17 environment. The retrofitting allows to reduce heating and cooling needs of the building, as to convert it to a nearly zero energy building (nZEB). It is equipped with a solar thermal and ground source absorption heat pump system, operating with the ground as source/sink. Besides the direct use for domestic hot water and for heating, solar thermal energy is used as heat source for the heat pump, or as regeneration of ground when the system operates for summer air conditioning. In this case, condensation heat from the absorption chiller can be usefully directed to post-heating coils of the air handling units, or to regenerate the ground as well. The system simulation allows to size the plant and to evaluate its performance in terms of solar ratio and primary energy ratio