A review of passive cooling of photovoltaic devices

Our planet's ecosystems depend on the energy received from the sun to form a bubble of life. Technically, other sources of energy are converted from solar energy. An effective way to directly convert solar energy to electricity is through photovoltaic devices. They could be manufactured on small scales and used in pocket calculations up to large scales power plants. These power stations, known as a solar farm, is composed of grid-connected photovoltaic arrays. The conventional solar cells' efficiency, ceiled by the Shockley-Queisser limit, is in the range of 15%-25%. The rest of the solar energy is converted to heat which would have a detrimental influence on power production and the life span of photovoltaic devices. Hence, employing cooling systems to regulate their operative temperature is crucial. Passive cooling technologies without consuming additional power and with little maintenance cost could be a practical option. In this study, the extensive work of researchers applying passive cooling techniques is gathered and compared. Also, the study will shed light on finding an appropriate cooling technique concerning geographical or environmental conditions. Papers related to each specific passive method are discussed, and the challenges which have remained unsolved are noted. Finally, most of the papers with different environmental conditions are mentioned in an inventory which makes the comparison and evaluation easier. Among the six passive cooling methods, natural air ventilation is economically the most viable option. Hence, designing complex fin structures to help enhance air ventilation is recommended for most of the problems. In the case of water cooling, floatovoltaics are highly recommended because of supplementary advantages such as reducing the algae growth and evaporation rate.