Abstract
Photovoltaic-thermal system (PVT) is a renewable energy based cogeneration system and it converts solar radiation simultaneously into thermal or electrical energy. The design space, a collection of all feasible system sizes, is developed based on the principles of Pinch Analysis to design isolated energy systems. The design space for a PVT system is governed by the electrical demand, the thermal demand, the load temperature of the thermal demand, and the boiling point of working fluid. However, it is observed that a PVT system generates excess electrical energy, especially during noon where the solar radiation is high. This excess energy can be used for some other useful work when battery is in danger of overcharging. In this paper, the impact of using of this battery excess energy on sizing of overall PVT system is presented. The comparative analysis of PVT system with the battery excess energy dumped into the storage tank or use of an auxiliary heater for the domestic hot water system are carried out in this paper. The analysis suggests that the supply of excess energy in auxiliary heater is beneficial.
