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Evaporative and thermoelectric cooling improve the efficiency of solar panels

Among several cooling methods reviewed in an article in Energies, evaporative and thermoelectric cooling offer substantial improvements in energy efficiency and a positive environmental footprint while maintaining economic viability.

With the construction of new large solar power plants, as well as an increase in rooftop solar installations for domestic and commercial applications, the International Energy Agency (IEA) predicts that solar energy will become the largest renewable energy source by 2030 [1].

 

Solar-energy-based photovoltaic (PV) panels constitute a widely used technology based on the principle of converting sunlight into electricity through semiconductor materials.

The main obstacle in this technology is that its efficiency decreases with high temperatures [2]. The constant contact of sun rays at the surface of the PV panel increases its temperature, thus decreasing its efficiency and output power. It was found that the efficiency of crystalline silicon solar cells falls by 0.45%–0.6% for every 1°C rise above STC (standard test conditions) in solar cell temperatures and varies according to the type of cell.

 

Researchers are actively exploring innovative strategies to enhance photovoltaic panel efficiency through advanced cooling methods. In a review article published in Energies, the authors conducted a comprehensive review of various cooling technologies employed to enhance the performance of PV panels, including traditional methods such as water and air cooling, along with innovative solutions such as incorporating phase-change materials (PCM), thermoelectric cooling, heat pipes, evaporative cooling, and nanofluids [3].

 

The authors found that among the reviewed cooling solutions, the automatic water spraying system, exhaust ventilated air, phase-change materials, and thermoelectric cooling methods exhibited the highest energy production levels. Furthermore, thermoelectric cooling, evaporative cooling, exhaust-ventilated air, and automatic water spraying demonstrated the greatest reductions in CO2 emissions. The thermoelectric cooling system had a maximum reduction in CO2 emissions, with an average of 28.334kg [3].

 

In terms of cost-effectiveness, thermoelectric cooling outperformed evaporative cooling, water-nanofluid cooling, and the automatic spraying system. Thermoelectric cooling delivered an average of 34.512 kWh and recorded the highest cost savings, with an average of USD 0.473 [3]. Moreover, the evaporative cooling technique, along with thermoelectric and PCM cooling methods, showed the shortest payback period.

 

Payback period of various cooling methods [3]

 

 

The authors conclude that evaporative and thermoelectric cooling emerge as particularly promising choices, offering substantial energy improvements, positive environmental effects, and favourable returns on investment.

 

Results from the study show the importance of integrating cooling strategies to improve the efficiency of photovoltaic panels and to maximize the generation of eco-friendly electricity.

 

For more information, the study is available in open access in Energies or on FRIDOC.

 

 

Sources

[1]  https://www.iea.org/energy-system/renewables/solar-pv

[2] Lazzarin R. Solar Cooling (2020), 40th Informatory Note on Refrigeration Technologies. International Institute of Refrigeration (IIR), Paris. http://dx.doi.org/10.18462/iif.NItec40.12.2020

[3] Ibrahim, T.; Abou Akrouch, M.; Hachem, F.; Ramadan, M.; Ramadan, H.S.; Khaled, M. Cooling Techniques for Enhanced Efficiency of Photovoltaic Panels—Comparative Analysis with Environmental and Economic Insights. Energies 2024, 17, 713. https://doi.org/10.3390/en17030713