Exergo-economic analysis method and optimization of a novel photovoltaic/thermal solar-assisted hybrid combined cooling, heating and power system

Abstract

This study integrates concentrated photovoltaic/thermal (PV/T) solar collectors into a natural gas combined cooling, heating and power (CCHP) system to both offer efficient use of solar energy and reduce greenhouse emissions. Using exergo-economic analysis based on energy level, an optimization method was proposed and used to configure and determine the PV coverage ratio on the PV/T collector for minimizing the products’ costs of the hybrid CCHP system. The optimization method considers the users’ annual variable energy loads and transforms the off-design operation conditions to the design parameters by employing the heat storage ratio of thermal storage tank and supplemental heat ratio of absorption heat pump. Based on the validated thermodynamic modeling, an exergy and exergo-economic analysis of the hybrid CCHP system are presented to reveal the influences of the PV/T configuration on the exergy efficiency and the products’ cost. As the PV coverage ratio on the PV/T collector was increased, it was found that the specific cost of the CCHP system-generated electricity rose and then slightly dropped, while the specific cost of the heat exergy decreased, and then slightly increased. The optimal coverage ratio, at which the minimal specific cost of the system products was attained, had a value of 1.0. The integration and optimization of the PV/T decreases the specific cost of the system products by 6.4%. Compared to the conventional exergo-economics analysis method, the specific cost of system electricity using the exergo-economic analysis based on energy level is 20.3% higher, and the costs of heat exergy are decreased.