Transparent insulation materials; Solar glazing; Transmittance-absorptance product; Solar energy materials
The transmittance-absorptance product of solar glazing containing the transparent insulation
material (TIM) of square celled honeycomb is investigated. A method is developed for the
determination of transmittance-absorptance product of beam, sky and ground diffuse solar
radiations using the individual transmittances of cellular array and encapsulating covers; the
internal reflections are taken into account. Three practical cases; cellular array, cellular array with top cover, and cellular array with top and bottom covers are considered. The results are presented for beam radiation as a function of angle of incidence and sky and ground diffuse radiation as a function of tilt angle. The predicted results are tested by measuring the global radiation transmittance of commercial TIM; the predicted results deviate from the measurements by an average of 2.0%.