The collector perform high absorptivity ,low emission rate ,well-structured,reasonable designed and high thermal efficiency.. ... 0.7mm, width of Calandria is 0.5mm.4.Glass Cover:Low-iron tempered glass has more than 92% transmittance,with width 3.2mm ... and durable.5. Insulation layer:composed of 25mm high density glass wool plate,insulation layer guarantees to reduce heat loss to ...