Mathematical modelling of a dual-fluid concentrating photovoltaic-thermal (PV-T) solar collector

This study presents an improved photovoltaic-thermal (PV-T) solar collector system that integrates a PV panel with a serpentine-flow stainless steel tube as the water-heating component and a double-pass air channel as the air-heating component. A Fresnel lens is used as the glazing and primary concentrator, and compound parabolic concentrators (CPCs) are used as the secondary concentrator. The system can simultaneously generate hot air and hot water in addition to electricity, and the total energy generated per unit area is higher than that of a single-fluid system. This triple-function PV-T solar collector is well suited for a wide range of thermal applications and offers options for hot and/or cold air and water use depending on the application and energy needs. This paper establishes, develops, and validates a conceptual design for a concentrating PV-T dual-fluid solar collector with 1D steady-state energy-balance equations for the dual-fluid (air and water) configuration. Next, this model is used to predict the performance of the dual-fluid solar collector with varying air and water mass flow rates. Then, the simulation results of the single- and dual-fluid operational modes are compared. The simulated results have shown that the total equivalent efficiencies for single fluid condition have ranged from approximately 30 to 60%, and increased to a maximum efficiency of near to 90% for the case of the dual fluids. The dual fluids operation mode has reduced the solar cells temperature and hence increased the electrical output.