Estimation of Total Solar Transmittance for Twin-Wall Polycarbonate Sheet with Rectangular Structure on the Basis of Experimental Research

Abstract

The consumption of heat energy as well as electric power in an exploitation process of a building construction depends among others on properties of materials applied to construct its partitions. Increasingly, glass is being replaced by plastics in transparent partitions, including multi-wall polycarbonate sheets. Light transmission and solar radiation transferred to the object’s inside through transparent partitions are decisive factors for its lighting and energy balance. The present paper presents an analysis, on an experimental basis, of the changes of total solar transmittance (TST) for a clear twin-wall polycarbonate sheet with a rectangular structure applied as a swimming pool enclosure. Research shows that values of the above parameter do not depend meaningfully on cloudiness but on time of day. Values of TST can change in the daytime depending on incidence angles and on shares of direct and diffusive solar radiation in global solar radiation. TST values are in the range 0.6–0.7, and they are lower than the value of 0.8, which is given by the producer in the product card.