Future development in the field of transparent insulation systems

The utilisation of solar energy in the area of active and passive thermal systems needs cover or glazing systems, which have both high total energy transmittance and good thermal insulation qualities. The recent development of transparent insulation materials (TIM's) allows to design optimised transparent insulation systems for application fields from flat-plate collector technology to daylighting systems. When TIM's are combined with selective coatings, low pressure or special gas fillings, heat resistances from the absorber to the ambient of more than 1.5 mhigh2K/W may be achieved, where the total energy transmittance (equivalent to the effective transmittance-absorptance-product) still is around 85 percent for vertical and around 70 percent for diffuse irradiation.