Improving the efficiency of photovoltaic cells using PCM infused graphite and aluminium fins

Abstract

The purpose of this paper is to assess, through experiment and Matlab modelling, whether the use of phase change material (PCM) infused graphite with an external finned heat sink is viable as a method of PV thermal regulation. The effect four different thermal regulation techniques (cases A, B, C and D) on the thermal performance, point-based efficiency and overall efficiency of a PV panel have been studied. These four cases are case A, the PV panel with no thermal regulation, case B, the PV panel with 30mm thick PCM infused graphite attached to the rear, case C, the PV with a finned heat sink attached to the rear and case D, the PV panel with a combination of PCM infused graphite and finned heat sink. Special attention has been paid to the effect that the infusion of PCM into graphite has on the thermal regulation effects of the PCM itself.The experimental setup consisted of two mono-crystalline silicon solar panels linked independently to a computer, which recorded the power generated from each solar panel, as well as the temperature at the front and rear of each panel. The insolation was supplied by two 500W halogen lamps positioned 0.15m away from the centre of each solar panel, with a peak insolation of 920W/m2. The intensity of the insolation was measured with an incident-light photometer. The power supplied to the halogen lamps was controlled by the computer and a simple voltage control device.Out of the four thermal regulation techniques, case D was the most effective at increasing overall efficiency of the PV panel, with the greatest overall efficiency increase of 12.97. The thermal regulation effects of PCM and heat sinks are additive since the PCM creates a shift in temperature rise, whilst heat sink reduces the peak temperature. The increase in thermal conductivity of the PCM from 0.25Wm−1K−1 to 16.6Wm−1K−1 provided by the infusion of PCM into graphite has significant added benefits over pure PCM. Further analysis based on overall efficiency demonstrates that combining PCM with heat sinks is in fact essential.