Theoretical effective reflectivities, absorptivities, and transmissivities of draperies as a function of geometric configuration

Abstract

S OLAE heat gain is a quantity of great importance in architectural design and in the evaluation of heating and air-conditioning requirements. In its determination it is necessary to know the physical properties of the transparent portions or fenestration. For the calculation of the heat transmitted by a window, constructed of one or more layers of ordinary or special glasses and Venetian blinds or draperies, information must be available on the individual layers. A method will be presented by which the apparent reflectivities, absorptivities, and transmissivities of draperies can be determined theoretically from the corresponding properties of the flat material. This information is usually available from the manufacturer. The theoretically obtained values are, in many cases, considered better than the experimental results, which varied somewhat according to the method employed. The theoretical values were close to the average value of a great number of readings over the hanging drapery.