Review of cooling techniques used to enhance the efficiency of photovoltaic power systems

Abstract

Photovoltaic (PV) panels are one of the most important solar energy sources used to convert the sun’s radiation falling on them into electrical power directly. Many factors affect the functioning of photovoltaic panels, including external factors and internal factors. External factors such as wind speed, incident radiation rate, ambient temperature, and dust accumulation on the PV cannot be controlled. The internal factors can be controlled, such as PV surface temperature. Some of the radiation falling on the surface of the PV cell turns into electricity, while the remainder of incident radiation is absorbed inside the PV cell. This, in turn, elevates its surface temperature. Undesirably, the higher panel temperature, the lower conversion performance, and lesser reliability over the long term occur. Hence, many cooling systems have been designed and investigated, aiming to effectively avoid the excessive temperature rise and enhance their efficiency. Many cooling methods are used to cool solar cells, such as passive cooling, active cooling, cooling with phase change materials (PCMs), and cooling with PCM with other additives such as nanoparticles or porous metal. In this work, the common methods utilized for cooling PV panels are reviewed and analyzed, focusing on the last methods, and summarizing all the researches that dealt with cooling PV solar cells with PCM and porous structures.

Effects of nanocoatings on the temperature-dependent cell parameters and power generation of photovoltaic panels

“…In general, the rate at which heat energy (of flux) is conducted between two bodies is a function of the temperature difference between them and the properties of the interface through which the heat is transferred (Sharaf et al 2022 ). Hence, the heat transmitted from the top to the bottom surface is directly proportional to their temperature difference (Yanniotis 2008 ).…”

“…While effective in controlling the temperature rise of PV cells, all these techniques involve significant capital expenditure and physical modifications to the plant installation, such as piping, fixtures, mountings, etc. All these systems will have a long payback period making them economically less feasible (Dwivedi et al 2020 ) (Sharaf et al 2022 ). Developments in the field of nanomaterials have resulted in the advent of specialized coatings for the panel surface.…”

Heat Pipe as a Passive Cooling Device for PV Panel Performance Enhancement

“…The effects of temperature on photovoltaic efficiency can attribute to the influences on the current and voltage of the PV panels [1]. The increase in surface temperature of the PV cell, increases the circuit resistance, and this limits the velocity of the electron, which directly affects the open circuit voltage besides badly influencing the cell material [2]. The voltage drop-in or temperature rise unit, called temperature coefficient, describes the temperature reliance of the material used for PV cell performance analysis and indicates the strong dependency of PV power output on the surface temperature of the PV.…”

“…Sharaf et. al., [2] have reported, that heat pipe was the interest of some researchers to cool down the PV cell surface temperature passively. The obtained results from the studies shown an increment of the power output.…”

“…The obtained results from the studies shown an increment of the power output. The comparison between the difference of PV cells cooling technique has been discussed based on the PV surface temperature, initial cost, heat transfer rate, the power required and the life time of each technique [2]. Despite of high initial cost, the heat pipe proved to be low in maintenance cost, hight heat transfer, zero additional power required and longer lifetime.…”