Thermal management systems for Photovoltaics (PV) installations: A critical review
Strong solar radiation and high ambient temperature can induce an elevated Photovoltaic (PV) cell operating temperature, which is normally negative for its life span and power output. Different temperature dependences for PV performance have been reported and it has been found that the efficiency of crystalline silicon cells drops at a rate of around 0.45%/°C. Various cooling methods have been proposed to achieve lower PV cell temperature in favour of higher cell efficiencies. Passive cooling by heat spreader or heat sink can provide enough cooling to get a relatively low cell temperature even for Concentrator PV (CPV), but the heat sink surface area can be extremely large. Natural ventilated systems can achieve PV temperature in a range of 50–70 °C and forced ventilated systems are found to achieve a lower temperature range of 20–30 °C at the price of parasite electric consumption. Forced de-ionized liquid immersion cooling, jet impingements techniques and heat pipe cooing mainly applicable to CPV systems and can achieve a temperature range of 30– 96 °C. Phase change material (PCM) system due to a choice of melting temperature, amount of material to be used, and different system designs is a promising thermal management of flat plate PV and can maintain PV temperature below its melting temperature e.g. 27 °C for a relatively long time. A facility to re-utilize of the heat energy stored in PCM is encouraged.