Solar panel reflectors Solar panel reflectors © Joshua M. Pearce

Using reflectors to increase the yield of solar panels

Ecohome March 13, 2018, 9:32 a.m.
Lydia Paradis Bolduc

A study showed that reflectors on solar panels can increase their performance by up to 30%

The ongoing drop in cost for home solar power generation has led to a dramatic increase in the rate of installations, for both residential and commercial use. Increasing the yield through reflection could make that an even more affordable energy supply option.

Most of the advances in solar power production come from increasing the efficiency of the photovoltaic cells; the goal being to increase the watts produced per panel. Joshua M. Pearce, professor of engineering at Michigan Technology University, recently published an article in Green Building Advisor that demonstrates the results of his research on this. Working in conjunction with a study group in Canada, his team has demonstrated that the use of mirrors, or reflectors, to further illuminate the panels could increase their performance by as much as 30%.

This cheap addition to boost power from solar arrays is not yet very widespread. According to Dr. Pearce, this is mainly due to concern on the part of manufacturers and their warranties. The calculation for the performance and longevity of panels is based on the assumptions of very specific energy input. If more light is fed to the panels through a reflector, the temperature variations of the panels themselves will be greater, and the energy output is less predictable. According to Pearce, many manufacturers are unnecessarily concerned about this leading to potential failures.

To counteract what he considers a false conclusion, Pearce and his team have put in place a reliable technique that can predict the effects of reflectors on panels. They use bidirectional reflectance distribution function (BRDF) simulations that calculate how light bounces off an uneven surface, and predict its dispersion. This makes it possible to predict how light will react with all types of reflectors, even imperfect ones since reflectors do not necessarily behave like mirrors.

The model was tested in real-life conditions in Kingston, Ontario and produced impressive results: the efficiency was increased by 45% in a case with poorly-angled panels, and by 18% when tested with a system that had optimally-angled panels. According to Pearce, in most cases with well-placed solar arrays, the energy collected should rise on average by 30% with the inclusion of reflectors.

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