Vacuum glazing units and solar collectors

Possible application of vacuum glazing (VG) units for transparent insulation of solar collectors (SC) to reduce their heat losses is considered. Taking into account the SC operating conditions, the heat insulating parameters of VG samples measuring 0.3 × 0.3 m² and 0.5 × 0.5 m² are experimentally studied and compared to those of double glazing (DG) of the same size. Basing on the experimental data, the order of the vacuum in the VG is calculated. The contribution of the vacuum gap to the total heat transfer resistance of the VG is evaluated.