Performance evaluation of a novel solar photovoltaic–thermal collector with dual channel using microencapsulated phase change slurry as cooling fluid

Abstract

In a photovoltaic–thermal solar collector, only a small percentage of the absorbed solar radiation can be converted into electricity, the rest is converted into heat. The waste heat gathering and transferring rate is the key to improve the module efficiency. In this work, a type of microencapsulated phase change slurry was employed in the photovoltaic–thermal solar collectors to improve the thermal and electrical performances. The designed photovoltaic–thermal collector was reduced to a 2–dimension physical model and numerically studied. Solar cells temperature, outlet temperature and pressure drop of the fluid, electrical, thermal and overall net efficiency were simulated and analyzed to evaluate the dynamic performance of the hybrid photovoltaic–thermal collector. Energetic efficiencies for photovoltaic–thermal model with various light concentrations versus the mass flow rate of the microencapsulated phase change slurry flow were investigated. When the concentration is 10wt%, the photovoltaic–thermal collector obtained the highest net efficiency with the flow rate of 0.02kg/s and the piping height of 10mm. And it was found that the temperature variation of both fluid and PV cells employing microencapsulated phase change slurry was much smaller than water, which would improve both thermal and electrical performances. Then the optimized photovoltaic–thermal module was simulated in a daytime with the comparison of conventional water type. It was found that overall net efficiency of the photovoltaic–thermal collector with microencapsulated phase change slurry reached 80.57% at 11:00, about 1.8% higher than the conventional water type. The maximum overall net exergy efficiency was 11.4% in the morning. Above all, the proposed photovoltaic–thermal collector with microencapsulated phase change slurry flow has potential for further development in solar collector.