Thermal management of photovoltaic solar cells using polyethylene glycol 1000 (PEG1000) as a phase change material

Photovoltaic (PV) solar cells are used for the conversion of renewable solar to electrical energy. Elevated operating temperature more than 25 degrees C causes a drop in conversion rate between 0.4% and 0.65% per Celsius degree. Different heat removal techniques have been employed to maintain PV cells at an optimum temperature. One of the cooling methods which have been presented in the literature is using free or forced convection in the back of the panel. Phase change materials (PCMs) are substances that absorb and release energy during the phase change process (solidification/liquefaction) as a latent heat. One of the major advantages of using PCMs is the constant temperature during the process. Phase change materials can be used as one of the most efficient techniques to absorb the excess heat from the back of the solar panels. This paper presents the results of an experimental investigation for a system including a solar cell and phase change materials (PCMs) for the thermal management of the cell to maintain the temperature of the panel close to the optimum operating temperature. The solar radiation of 800 W/m2 and panel inclination of zero and 15 degrees has been applied in the experimental runs. Polyethylene glycol 1000 (PEG 1000) with melting point of 38-40 degrees C has been used as a phase change material. The results show that adding the PCM in the solar panel improves the efficiency of the system up to 8% in the conversion of solar to electrical energy. The panel temperature is also decreased by 15 degrees C in comparison to the single panel without PCM. It can be concluded from the results that using phase change materials is seemed to be an effective method for thermal management of the photovoltaic solar cells.