Leverkusen, Germany -- In close cooperation with Bayer MaterialScience, manufacturer puren GmbH of Überlingen, Germany has developed the Bomatherm, a solar air collector and roof-insulation system. In this device, energy from solar radiation is intelligently combined with highly efficient thermal insulation, said an announcement from the two companies.
The air collector/roof- insulation system is laid like a roof and performs five functions at once: vapour barrier, thermal insulator, rainproof roof substructure, cladding and solar collector.
The development was made possible by a newly developed sheet technology based on BMS's polycarbonate and rigid polyurethane foam, the statement added.
"Its key benefit is its outstanding energy efficiency," explains Guenther Winnerl, head of marketing, polycarbonate sheets at BMS. "The solar collector, which is made of highly heat-resistant Makrolon sheet, produces usable energy in the form of hot air 'free of charge,' said Winnerl, adding that the energy can be used directly, without further conversion, for heating.
"Moreover, the insulation, which is based on polyurethane rigid foam, does not create thermal bridges, so only a negligible amount of heat energy escapes through the roof and the collector is optimally insulated against energy losses," said Christoph Schlott of puren´s project management.
Rigid PU foam offers very efficient thermal insulation, as well as being lightweight and durable," so the panels not only give outstanding insulation at minimal wall thicknesses, but are "lightweight, durable and easy to machine thanks to their excellent compressive strength and dimensional stability," according to Thomas Seeger, a BMS expert in PU insulation.
The system is based on a simple principle. Cold air flows through the collector. By means of an absorber, solar energy is transmitted to the air. The warm air can be used for room heating or for heating domestic water by means of a heat exchanger. It can also be fed into a heat pump or a geothermal energy store, or used to operate agricultural and industrial driers, for example for drying tobacco, hay, fruit, plaster or paint.
The companies point out that Bomatherm is equally suitable for private and industrial use. The energy savings and the low follow-up and operating costs mean that the investment pays off within a few years, especially as many of the costs would also be incurred with "normal" roof cladding.