Environmental Performance Evaluation for a Small Scale Trigeneration System

The modern buildings must have very high standards and require highly efficient energy supply systems due to space limitations for renewable installations. Electricity and thermal energy can be produced simultaneously with a photovoltaic-thermal (PVT) system. In the paper, an innovative concept of PVT system for a hospital is studied. PVT collectors serve as both a heat source and a heat sink for a reversible heat pump in the examined system. Due to the reduced electricity consumption from the network for heat rejection, the overall efficiency was improved by using a reversible water-to-water heat pump as heat and cold source compared to a conventional solar cooling system. Primary energy savings can be achieved with a maximum utilization of PV for electricity, heating and cooling (as air conditioning). The paper presents an original methodology for determining the environmental impact of the real PVT operation. The case study shows that for a real 4kWp PVT, the yearly energy savings reduce the greenhouse gas (GHG) emissions with 281.8 kg/year for SO₂ and 152.4 for CO₂.