A hybrid air PV collector: The hot air behind the photovoltaic modules is sucked into a ventilation system. Photo: Conserval Engineering
With Solar Duct PV/T, Conserval Engineering supplies modular hybrid elements which can be fixed to flat roofs. The Canadian company combines trapeze-shaped metal plates, which it normally uses as solar air collectors, with solar modules which are mounted above. The metal plates are perforated so that air heated above the plates can be sucked into a ventilation system. The airflow also extracts heat from the solar modules and thus cools them.
The Solarwall plates and the photovoltaic modules in the Solar Duct PV/T are mounted on a sloping frame which can be assembled and connected to a ventilation system. Conserval Engineering had its system tested last year at the Canadian National Solar Test Facility. According to the company the tests showed that it is possible to get two to three times as much heat from solar modules as electricity. The combined system increased the total solar efficiency to over 50 % compared to the 10 to 15 % of a typical photovoltaic system. “Because we draw heat off the solar modules and thus lower the operating temperature, we get significant gains in system performance and can use the heat for heating purposes,” says the head of Conserval Engineering, John Hollick. He had his system tested with various module types, including ones by BP Solar, Evergreen Solar und Unisolar.
This text was written by Joachim Berner, a German journalist and solar thermal expert.