It is a glass wool board manufactured with black color in special sizes. It is used for thermal insulation of solar collectors and tanks.
For the thermal insulation applications of solar collectors, collector blankets and boards are used together. It is also possible to use glass wool boards faced with aluminium foil in order to prevent heat losses from absorptive surface to the inside body due to the radiation and in order to reflect that to the selective surface. If the case height is suitable, the product is placed between the absorbing surface and the soffit insulation by leaving a 10 – 20 mm gap. In order to ventilate the collectors, 2-3 mm diameter holes should be drilled where rain water cannot reach. Otherwise, it may cause condensation of water vapor on window panes at nights and that may affect the efficiency of the collector.