Performance Analysis of a bi-fluid type photovoltaic/thermal (PV/T) Solar Collector under low-cost solar simulator and tropical climate conditions

Performance analysis of a photovoltaic/thermal solar collector with bi-fluid configuration (air and water) was conducted under a low-cost solar simulator and under real sky condition of the tropical climate of northern peninsular Malaysia. The PV/T solar collector is capable of producing three different modes of fluid operation namely the i) air mode, ii) water mode, and iii) simultaneous (bi-fluid) mode. The third mode of fluid of operation is the primary focus in this paper. This paper highlights the performance of the collector indoor and outdoor, in the view of experimental and 2-D theoretical analysis at steady state. For the indoor testing, the setting of the test rig facilities are suitable for the mathematical validation purposes and also to investigate the collector performance with the variation in the mass flow rate. However, due to different spectral distribution of the simulator and the real sunlight, inconsistencies in the thermal and electrical performance of the collector between indoor and outdoor testing were observed. From the indoor experimental analysis, at wind speed of 1 m/s and average solar radiation of 700 W/m2, when air was fixed at flow rate of 0.0262 kg/s while water mass flow rate was varied from 0.0017 to 0.0265 kg/s the electrical and thermal performance of the PV/T solar collector are ranging from 4.10% to 4.20%, and 54.51% to 65.70 %. Meanwhile when water was fixed at flow rate of 0.0066 kg/s, with air mass flow rate was increased from 0.0074 kg/s-0.090 kg/s, the aforementioned efficiencies are ranging from 4.10% to 4.40%, and 51.87% to 66.12% respectively. When tested under real sky condition, at air and water mass flow rate of 0.0262 kg/s and 0.0066 kg/s respectively, with average wind speed of 3.30 m/s, the electrical efficiency and total thermal efficiency varies within 6.20% - 9.78%, and 43.12% - 47.85% respectively. The theoretical analysis was compared with the experimental analysis by comparing the trend of the curves and also by using mean absolute percentage error analysis (MAPE). The curves were found to be in good agreement and the computed MAPE for the fluids’ output temperature are less than 1.5% for both indoor and outdoor analysis. The feasibilities of incorporating two different types of working fluids into the same PV/T solar collector has been proven based on the thermal and electrical energy output of the collector when it was tested in the lab and under the real sky condition. Therefore, this research is concluded to serve as the starting platform for further research in the bi-fluid type PV/T solar collector, both experimental and theoretical wise