Thermodynamic and transient analysis of the hybrid concentrated photovoltaic panel and vapour compression cycle thermal system for combined heat and power applications

摘要

This research conducts a thermodynamic and transient analysis of the hybrid concentrated photovoltaic panel and vapour compression cycle thermal (CPV-VCC/T) system that is designed for combined heat and power purposes. The model includes both the VCC's thermodynamic model and the evaporator (CPV side) heat exchanger's convective heat transfer effect. Various commercial refrigerants (R123, R22, R245fa and R134a) are analyzed where their performances are assessed in terms of coefficient of performance (COP) and the CPV's resulting operating temperature. After the comparative steady state analysis, the CPV-VCC/T system is then tested in a two-day transient simulation involving varying irradiances and hot water demands. Steady state results demonstrate that the COP efficiency relative to Carnot will generally decrease as the condenser temperature increases. Also, although refrigerants R134a and R22 yielded up to 12% higher static COPs than R245fa and R123, the yielded electric energy gain from the two-day transient simulation is different by no more than 1.5%. Positively, the CPV-VCC/T system is found to yield 35% more electric energy than the conventional electric heating system. Although the CPV-VCC/T system yielded 5% less electric energy than direct water cooling, the CPV temperature was successfully maintained at 330 K as opposed to over 380 K.