Glass–azimuth modification to reform direct solar heat gain

A means of reforming the solar heat gain, and hence, energy conservation in air-conditioning systems is suggested and studied. The main idea is to control the solar gain by horizontal rotation of glass windowpanes, i.e. modifying the glass–azimuth irrespective of the original orientation of the building wall. The influence of the rotation angle, magnitude and direction, on the instantaneous, daily and seasonal solar heat gain is investigated in detail. A computer program is coded to carry out the extensive computations. This program is prepared in a general and versatile form, in the sense that it can be used at any location and time, for any wall orientation and any type of glazing characterized by the extinction coefficient, index of refraction, and thickness. The study helps the designer to select an optimum glass rotation angle which increases or decreases the heat gain depending on the objective. There may be two optimum rotation angles, the first results in reducing the air-conditioning system size, while the second angle decreases the energy consumption.