KTU 15 Solar Collector
Parameters and specification
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.
Solar fluid passes through a U-shaped copper tube down to the tube and when warmed up, it returns up to the header pipe. An aluminum lamella gathers heat from the entire inner surface of the evacuated tube and transfers it to the solar fluid inside the copper tube. The lamella fits precisely to the glass tube and embraces tightly the copper tube with solar fluid. Thanks to this and to the very short distance between the absorber and the solar fluid the heat transfer is highly effective.
Thermal insulation of the header pipe is formed by a 3cm layer of mineral wool with transverse-oriented fibers and an aluminum foil to minimize heat losses of the header.
Regulus solar collectors are developed and manufactured by Regulus in the Czech Republic. Their excellent parameters and mechanical resistance are verified by a certification by an authorized body according to the latest European standard EN 12975-2. This standard involves among others also measurement of the performance and efficiency, of mechanical resistance incl. hail resistance and long-term weather resistance.