Terraced houses in the Netherlands
In the urban environment, space is a rare commodity. In European cities for example, with typical terraced houses the roof space is perhaps just enough to cover with sufficient solar panels to provide electricity for the households, but that’s it. These panels will convert sun light into electricity with an efficience of say 10-20%. On sunny days the temperature of the solar panels can reach 35 Celcius above ambient temperature. The idea of PVT (Photo-voltaic Thermal) collectors is to use that heat as well, for tap water and space heating.
Research into PVT systems was carried out at MIT in the 1980s and the University of Eindhoven and ECN in the mid 1990s, both in the Netherlands. The limitation is that the higher the temperature of a solar panel, the lower the efficiency of the photo-voltaic conversion. Having a glass plate in front of a panel is not a good idea in the middle of the summer. The more promising alternative is to use a cooling liquid through pipes mounted at the backside of a panel. Another idea might be suitable for solar panel at ground level (garden), where glass plates will be removed in the summer, when no heating is necessary anyway, just electricity. During the heating season, the glass plates can be put in front of the panels again and the heated air between glass plate and panel can be pumped into the living space.
Test results from hybrid collector installation in Leipzig/Germany: add 3 units of thermal energy for 1 unit of electricity.
Hybrid collectors, delivering electricity and thermal energy to a city swimming-pool.
[tue.nl] – PV Thermal Systems: PV Panels Supplying Renewable Electricity and Heat
[ecn.nl] – Photovoltaic/Thermal Solar Collectors and Their Potential in Denmark
[faz.net] – Hybrid-Kollektoren liefern keine Wunder
[stoffstrom.org] – Strom und Wärme mit Hybrid-Luft Kollektoren (slides 46-47, 50)
[solimpeks.com] – PV-T Hybrid Collectors
[grammer-solar.com] – Grammer Solar homepage
[sciencedirect.com] – book: Performance and Economic Analysis of Hybrid PVT Collectors in Solar DHW System
[macsheep.spf.ch] – Solar heat pump system with hybrid PVT collectors
[solar-more.de] – Volther PowerVolt Hybridkollektor 190 watt
[aes-energie.com] – Volther PowerVolt Hybridkollektor 190 Watt