Anyone planning to install a photovoltaic system on the roof of their house will not be able to avoid the issue of winter at some point. What if it snows and the system can then generate no or only very little electricity? If the system is on a roof with a pitch of 30 degrees or ideally 40 degrees, then the snow will slide off the slippery modules on its own. If this is not the case, one waits for milder temperatures or has to remove the snow from the solar system by hand. The latter not only takes time and is a lot of work depending on the size of the system, it also involves a serious risk of accidents.
PVT collectors do not have this problem in the rules. The photo shows a PRISMA® PVT 3.0 test installation in the Upper Palatinate. As you can see, the snow has not slipped off the modules, but it has thawed on the modules. How can this be, if there is snow on the modules, surely they cannot produce electricity and therefore heat? This is true, but the PVT modules have a decisive advantage over simple PV modules; underneath the PV modules there are copper pipes that are connected to a brine circuit. When this circuit starts, the frost-proof solar fluid is heated by the heat exchanger in the buffer tank. As a result, the snow on the PRISMA® PVT collectors then thaws. In this example, the brine circuit was started manually. The modules were free of snow after about 30 minutes and were producing electricity again.
