Certification of hybrid PV and solar heat
A few years ago, a Dutchman invented a combined solar panel that not only generates electricity, but also uses waste heat from photovoltaics to heat water. Now, researchers have come together to develop certification standards for the hybrid technology.
In mid-2011, Stefan Roest of the Netherlands invented a new hybrid collector. The heat medium flows through small aluminum channels instead of thick copper tubes, and he uses thin film instead of crystalline solar cells.
The Solarzentrum Allgäu and TÜV Rheinland are working with the Fraunhofer Institute for Solar Energy Systems (ISE) and the University of Düsseldorf to come up with new standards for hybrid collectors, which use solar energy to create both electrical current and heat. The solar cells on the surface heat up, and the heat is passed on to the thermal absorber below. The absorber takes the heat storage, thereby drawing off heat from the solar cells, which work at greater efficiency as temperatures drop. Basically, the system uses waste heat from photovoltaics.
Hybrid collectors are already on sale, but "the products will be a hard sell as long as there are no standards to certify safety," explains Willi Bihler, project manager and director of Solarzentrum Allgäu. E withstand are much greater than with conventional solar thermal collectors. After all, the temperature difference between the waste heat from the photovoltaics on the top of the collector and the temperatures inside can be much greater than with normal collectors.
Scheduled to run for 18 months, the project will present its results for national and international committees that adopt standards. (Sven Ullrich / Craig Morris)