Numerical and experimental work to assess dynamic advanced exergy performance of an on-grid solar photovoltaic-air source heat pump-battery system

Abstract

In the near future renewable energy powered air conditioning systems will play an important role in the building sector. In this study a solar photovoltaic powered air source heat pump with a battery system was modeled and numerically simulated using Transient System Simulation Tool. The experimental studies were also carried out to validate the developed model. The novelty concerns to integrate conventional and advanced exergy analyses into the numerical model to annually determine the exergy destructions with main sources (exogenous endogenous unavoidable avoidable and their combination) at a component level. The results obtained from the experiments showed that on-site weather conditions air temperature difference occurring between inlet and outlet of the evaporator unit and the power flow between the main system components were considerably modeled well. Based on the simulated studies conventional exergy analysis revealed that the highest annual exergy destruction amount was due to the photovoltaic panels with 23.3 MWh while the lowest one occurred in the batteries with 156.1 kWh. This also indicated that the highest potential for improvement lays within the photovoltaic panels. According to the simulated results considering the advanced exergy analysis the yearly exergy destruction amount in the photovoltaic panels and in the heat pump (920.6 kWh) were fully endogenous corresponding to unavoidable values of 21.3 MWh and 455.3 kWh respectively. On the other hand all the main sources of exergy destruction were seen for both inverter and batteries where the contribution of the unavoidable endogenous (429.9 kWh) and unavoidable exogenous (66.2 kWh) parts were annually found to be significant for the inverter and the batteries respectively.