I’ve written in the past about passive solar heat, such as Trombe walls, solar furnaces or solar heating walls. The idea is more familiar is solar hot water systems. But did you know that solar heat and solar electricity can be combined?
Hybrid solar panels have been on the market for a while, but the most versatile option I’ve come across is from French company Systovi. I encountered them at the EcoBuild exhibition recently. They sell a multi-functional system called R-Volt that combines electricity, heating, cooling and ventilation, all off one set of hybrid panels.
All solar panels get hot in the sun, and too much heat actually reduces efficiency. On a blazing hot summer’s day your panels may be losing 10 to 25% efficiency. Hybrid panels turn this problem into an advantage by running a current of air through the panel, harvesting the heat and keeping the panel cool. The panel runs at full efficiency, and you can pipe the heat into the building to reduce heating costs in the winter. Or you can put the heat into a hot water system, or both. Systovi call this ‘solar aerovoltaics’.
On hot summer nights the process can be reversed. The panels cool in the night air, and cold air can be run into the building to maintain a comfortable sleeping temperature. Since the warm or cold air is run through a filter on the way through, the whole house can be ventilated, improving indoor air quality and health.
This sort of solar power is often abbreviated to solar PVT, for photovoltaic + thermal. For most ordinary householders, it’s the most straightforward way of incorporating renewable heat into our homes – the next big challenge after renewable energy. Unfortunately, awareness of PVT is fairly low. The market is small, and they’re a bit niche and therefore expensive. But since they’re more efficient than normal solar panels and offer additional benefits, they’re going to be more common in future.