While solar panels generate clean electricity, many of the maintenance practices are often not so clean, especially when it comes to cooling. A team from Stanford, however, claims to have found the recipe for making a new coating that allows panels to cool themselves without wasting any water or energy, while boosting their power generation.
A recognised disadvantage of regular solar cells is the fact that no matter how efficient they are, their maximum capacity is never reached. Many reasons are hidden behind this, but the most common one is the overheating of the panels. If overheating is not dealt with, it results in decrease in efficiency and shortening of solar cells’ lifespan. To be more precise here, it has been established that for every degree Celsius increase in temperature of the solar cells, their efficiency drops by as much as 0.5%.
Solar panel owners and manufacturers have come up with different ways to tackle the problem, introducing different coolants or high-tech ventilation systems, but unfortunately these waste a lot of energy and water.
Now, a team from Stanford University, led by Professor Linxiao Zhu, developed a new coating, or a passive cooling technology, which is essentially a layer of silica glass, patterned by small pyramid and cone-like structures. When applied onto regular solar cells, the pattern redirects the thermal radiation, or heat, away from the surface, providing the optimal radiative cooling capability.
As reported in the journal Optica, by the Optical Society, the choice for these structures was made after a series of experiments, during which the team tested various shapes as opposed to flat silica surfaces. The authors opted for the pattern, which allows visible light to pass through the layer uninterrupted, while stopping the most of the incoming thermal radiation.
According to the authors, the special coating does not have any negative influence on the performance of the solar cells. The only thing it does is to effectively send heat away from the cells by enhancing radiation at predetermined thermal wavelengths, which ultimately prevents loss of energy and decrease in lifespan.
The technology is still in its testing stage, although it is now moved out of the lab and it is being optimized for large scale outdoor environments.
Image (c) L. Zhu