Solar photovoltaics thermal management by employment of microchannels: A comprehensive review

Abstract

Issues related to the heavy consumption of fossil fuels namely coal and oil have necessitated development of renewable energy sources as alternatives. Solar photovoltaic (PV) modules are one of the most attractive options for electricity generation by use of solar energy as the most abundant renewable energy source. One of the main disadvantages of PV cells is their relatively low efficiencies that leads to low power generation intensity. In this regard, concentrators can be applied to exploit further electricity per area of the cell; however, it causes increase in the temperature and consequently reduce the efficiency. To overcome the efficiency degradation due to the temperature increase, thermal management of cell has been introduced and applied recently. One of the efficient active techniques for cooling PV cells is making use of microchannels for circulation of coolants inside it. This article reviews the research works implemented on the use of microchannels as thermal management unit of PV cells. According to the findings it can be concluded that performance of this cooling techniques is influenced by variety of factors like the coolant mass flow rate, configuration and characteristics of microchannels, thermophysical properties of coolant and heat transfer mechanisms. It is reported that employment of microchannels with modified architecture can lead to better thermal management and consequently higher efficiency of the cells. Furthermore, it is found that use of modified coolants, i.g. nanofluids, would result in higher heat removal and electrical efficiency. One of the main challenges in use of microchannels for thermal management is its manufacturing and related difficulties and issues.