Dual-Use Solar: PV Panels Now Can Heat Your Home's Water

icture this: solar panels on your roof don't just slash your electricity bills – they also supply hot water for your daily use. Scientists at the Multiphysics Interaction Lab (MiLab) in the United States have introduced a new photovoltaic-thermal (PVT) solution that not only ramps up the efficiency of solar panels but also turns the heat they generate into a bonus: hot water for homes.

A Two-in-One Energy Solution

This technology hinges on a simple yet effective system of parallel water pipes attached to the backside of solar panels. This cooling mechanism significantly drops the operating temperatures of the panels, boosting their efficiency. However, the real game-changer is the system's ability to convert the waste heat generated during the cooling process into domestic hot water.

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The Science Behind the System

The experimental setup revolved around a 250W polycrystalline PV panel oriented south with a 30-degree tilt. Copper pipes, encased in aluminum for added durability, were affixed to the panel. As water circulated through these pipes, it effectively removed excess heat, keeping the panel cool and optimizing its efficiency.

The setup also included a hot water storage tank and an 11 W centrifugal pump, ensuring a constant flow of water at just the right rate. The team used an array of sensors and measuring devices to track everything from water temperature to solar radiation.

Impressive Results

During trials in Zouk Mosbeh, Lebanon, the PVT panel outperformed a standard solar panel without cooling, generating 4% more power thanks to the copper pipes. The system achieved an average electric efficiency of 11.5%, compared to the 10% efficiency of the non-cooled panel. Furthermore, the overall efficiency reached approximately 75%, with the thermal efficiency from waste heat recovery standing at 60%.
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While the results are encouraging, there's room for improvement. According to scientists, fine-tuning the cooling system and better handling the cooling water could enhance the performance over a longer period, paving the way for even more impressive outcomes down the line.

Sources:

https://www.sciencedirect.com/science/article/pii/S2666202723002537