To prevent solar cells from overheating, researchers have developed decoupled photovoltaic thermal systems, which use a liquid to filter out excess heat and light. By drawing away ultraviolet rays that would overheat the solar cells, the liquid filter keeps solar cells cool while storing the heat away for later use.
Decoupled photovoltaic thermal systems have traditionally used water or nanoparticle solutions as their liquid filters. The trouble is that water and nanoparticle solutions aren’t very good at filtering out UV rays.
“De-coupled photovoltaic-thermal systems utilize liquid filters to absorb non-effective wavelengths, such as ultraviolet, visible light, and near-infrared. However, water, a popular filter, cannot effectively absorb ultraviolet rays, which limits system performance,” a research team at the Korea Maritime & Ocean University (KMOU) explained to CleanTechnica.
The team at KMOU found that fish oil excelled at filtering out excess light. While most water-based decoupled systems operate at 79.3% efficiency, the KMOU team’s fish oil-based system achieved 84.4% efficiency. For comparison, the team measured standalone solar cells as operating at 18% efficiency and standalone solar thermal systems at 70.9% efficiency.
“The [fish oil] emulsion filter effectively absorbs ultraviolet, visible light, and near-infrared wavelengths, which do not contribute to electricity generation in PV modules, and converts them into thermal energy,” the team’s report read.
Decoupled photovoltaic thermal systems can provide both heat and electricity. “The proposed system can even be operated under specific requirements and environmental conditions. For example, during summer, the fluid in the liquid filter could be bypassed to maximize electricity production, while in winter, the liquid filter could capture thermal energy for heating applications,” the KMOU team reported.
As demand for renewable energy increases, researchers have been working tirelessly to increase the affordability, sustainability, and efficiency of solar energy. Durable perovskite solar cells are high-performing without breaking the bank, while silicon nanoparticles could convert low-energy light into high-energy. The KMOU team’s discovery represents another step forward for the efficiency of more affordable energy.
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