Products reached the level of
1, the use of special hard high borosilicate 3.3 glass tubes (Pyrex), the transmission ratio is less than 0.89, the bending degree is less than or equal to 0.12%.
2, the solar selective absorption coating of solar absorption than alpha is greater than or equal to 96%; solar selective absorption coating hemisphere than epsilon h is less than or equal to 5% (70 DEG C) emission.
3, air drying function parameters and solar irradiance G is greater than or equal to 700w/m2 and environment temperature of 5 DEG C is less than or equal to TA is less than or equal to 28 DEG C, with water refrigerant heat transfer, air drying temperature ts, air drying function parameter Y = (TS TA) / g, y is greater than or equal to 185 M2 DEG C /Kw.
4, sunning solar radiant exposure, solar irradiance G is greater than or equal to 700w/m2 and environment temperature of 5 DEG C is less than or equal to TA is less than or equal to 28 DEG C, with water refrigerant heat transfer. At the beginning of the temperature not below ambient temperature, stuffy drying to a temperature increase of 35 DEG C required solar radiant exposure quantity h is less than or equal to 3.0MJ/ m2.
4, the gas pressure inside the vacuum layer 10-3Pa < 3 * P.
5, the inner tube uncoated length is less than 20mm, to further expand the area of heat absorption tube, reduce the heat loss coefficient.