Energy and exergy analysis and optimization of a novel heating, cooling, and electricity generation system composed of PV/T-heat pipe system and thermal wheel

Abstract

The present study aims to compare the energy and exergy performances of photovoltaic/thermal-thermal wheel (PT) and photovoltaic/thermal-heat pipe-thermal wheel (PHT) systems. These systems are able to preheat/precool the outside air in the cold/hot season and supply part of the electricity needed by a building. In the PT system, the ambient air exchanges heat directly with the photovoltaic panels, while in the PHT system, the evaporator section of heat pipes located under the panels transfers the heat received from the panels to the air stream through the condenser section of heat pipes. The annual useful energy and exergy produced by the system were taken as objective functions, the two-objective optimization of the systems was performed, and the performances of the optimal systems were assessed. Overall annual analysis of outcomes showed that the highest useful energy output is achieved by the optimal PT system which outperforms by 2.1% than that of the optimal PHT system, while the maximum useful exergy yield is attained by the optimal PHT system, which is 5.1% higher than that of the optimal PT system. The thermodynamic performance improvement of the PHT system is due to the electricity production increment by recovering the waste heat of photovoltaic panels.