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An international research team has placed a neem oil tank on the back of solar modules to cool them. The proposed solution improves the performance of photovoltaic panels by up to 17.8%.
A group of scientists led by Kongu Engineering College in India investigated the use of waste neem oil as a cooling solution for photovoltaic modules.
Neem oil is extracted from the seeds of the neem tree and is commonly used as a medicine for some skin diseases.
The researchers explained that this oil acts as a phase change material (PCM), which can absorb, store and release large amounts of latent heat in defined temperature ranges. PCMs have often been used in research for photovoltaic module cooling and heat storage.
“Neem oil has a good thermal range, its density is physically high, it is chemically stable and non-corrosive, it does not pollute the environment, it is reusable and recyclable, and it is economically cheap and easy to dispose of,” they add. “Typically, any PCM used for refrigeration must have low thermal conductivity, stability and cyclability. “Neem oil meets all the limitations.”
For their experimental setup, the academics used 50 W monocrystalline and polycrystalline modules with a surface area of ??43.18 cm × 35.56 cm. At the rear, they placed an oil tank with a depth of 4.064 cm and filled it 83.33% with used oil. The rest of the rear side surface was kept as “breathing space.”
The oil was replaced every 30 minutes and cost 15 rupees ($0.18) per day for both monocrystalline and polycrystalline configurations. To make room for the replaced oil, the residual oil that was already used for cooling was dumped into a tank. A valve controls the tank, so, after use, “removing the neem oil is very simple,” the group emphasizes.
The setups were tested outdoors on an April day and compared to control setups without neem oil cooling. At peak radiation, the monocrystalline module supplied 39.9 W of power, while the polycrystalline module produced 41.6 W.
As for the monocrystalline and polycrystalline cooling systems with neem oil, their temperatures were reduced by 2.29% and 4.34%, respectively, while their efficiency increased by 15.0% and 17.8%, respectively.
The scientists compared these results with those obtained by other oils used for cooling purposes in previous publications, and found that neem oil achieved the best performance for cooling solar panels to date. “Coconut oil reaches 9.0% and 10.40%, sesame oil 8.90% and 13.90%, and peanut oil 14.0% and 16.80%, respectively. ", they noted.
After compiling these results, the scientific group compared them with the use of other edible oils as photovoltaic coolants, according to previous literature.
The temperatures of monocrystalline and polycrystalline systems with neem oil cooling are reduced to 2.29% and 4.34%, respectively, compared to monocrystalline and polycrystalline temperatures of edible oils: coconut oil is 3 .76% and 4.09%, sesame oil is 4.27% and 3.98%, and peanut oil is 2.25% and 4.30%, respectively.
The results are presented in the study “ A new method for improving the solar photovoltaic unit efficiency through neem oil as coolant medium for high power applications-an experimental investigation ” as a cooling medium for high power applications: an experimental investigation), published in Electrical Engineering .
The research team consisted of scientists from Coimbatore Institute of Technology, Ramakrishna Institute of Technology and Theni Kammavar Sangam College of Technology as well as Qatar University. |
