Tubular solar thermal collector / rectangular
REGULUS SPOL SRO
Vacuum insulation in glass tubes. Two concentric glass tubes are used, with vacuum between them. The ends of the tubes are sealed so the vacuum is guaranteed for a long time. Vacuum surrounding the absorber is a perfect insulation, minimizing heat losses in a similar way like a vacuum flask does. Thanks to that, nor the tiniest heat gain from cloudy skies gets lost and warms up the fluid in the solar collector.
There is a tubular absorption surface transforming the incident radiation to heat. The collector then exposes the same surface area to the incident sunshine in the morning, at midday and in the evening. Unlike in flat plate solar collectors, performance of evacuated tube collectors is not impaired by a low incidence angle of solar radiation. Thanks to the cylindrical absorption area, heat is gained also from the diffuse solar radiation. The absorption surface available to diffuse radiation is three times larger than that for direct sunshine. Thanks to this, KTU collectors show heat gains even at bad weather.