Combined building integrated photovoltaic-thermal collector with air source heat pump for cold climate

Abstract

A TRNSYS model was developed to conduct a comprehensive study of combining a building integrated photovoltaic thermal (BIPV/T) collector with an air source heat pump (ASHP) in an Archetype Sustainable House. The heat pump uses the warm air generated in the BIPV/T as the source for heat production. The coupling of BIPV/T and ASHP enables a highly efficient heating system in winter conditions. A numerical model was developed for an air-based PV/T collector. The model was used to predict the thermal and electrical performance of the collector and to conduct a comprehensive analysis for different configurations (number of PV/T panels in rows NR and in series NS) and different design parameters. TRNSYS simulation results showed that low air mass flow rate and low duct depth enhance the heat pump coefficient of performance (COP). The arrangement with a large number of PV/T systems connected in series has higher COP. The maximum obtained seasonal heating COP was 3.45, corresponding to duct depth of 1.5 in, NS=5 and low row mass flow rate of 0.03 kg/s. The heat pump cumulative electricity consumption for a typical heating season could be reduced by 20.2%. When the analysis was based only on sunny hours, the electricity consumption of the combined ASHP + PV/T system was reduced by 52% and the predicted seasonal COP of the heat pump was 5.98. A new full-scale test facility was presented to be implemented at Toronto and Region Conservation Authority to examine the performance of combining passive system and dynamic building envelope technologies (BIPV/T+ASHP+TES) under real weather conditions. It is important to match the maximum airflow for the BIPV/T system with the maximum airflow for the outdoor coil of the heat pump. The pressure drop inside the PV/T collector along with the connecting air duct from the BIPV/T to ASHP for a wide range of airflow rates and different duct depths was calculated. It was found that for air a flow rate around 2000 CFM, which is the maximum CFM for the custom-made ASHP for the test facility, the predicted fan energy was 195 kWh/year corresponding to 1.5 in. duct depth.