DETERMINATION OF GLAZING AREA IN DIRECT GAIN SYSTEMS FOR 3 DIFFERENT CLIMATIC ZONES

This study determines the glazing area in direct gain passive systems needed to ensure thermal comfort inside a building (room air temperatu re 20 +/- 2-degrees-C). A 4 m X 4 m X 3 m single zone isolated house i s analyzed in three different types of climates namely composite (8-de grees-C to 20-degrees-C, New Delhi), cold-cloudy (-2-degrees-C to 5-de grees-C, Srinagar), and cold-sunny (-14-degrees-C to -3-degrees-C, Leh ). The analysis is based on the periodic solution of the heat conducti on equations describing heat transmission in the building components, floor, walls, and roof, and the Fourier representation of the ambient temperature and the total solar radiation intercepted by the building envelope. Two types of construction are analyzed: the first type is a traditional construction with 22-cm-thick brick wall, plastered 15 mm on both the sides (U = 2.0 W m-2 K-1); and the second one is of the sa me type but with 10 cm of expanded polystyrene insulation on all the f our walls and the roof (U = 0.31 W m-2 K-1). It is found that for trad itional construction with U = 2.0 W m-2 K-1, the glazing U value has a lmost no effect on the room temperature even for large variation of th e glazing area ( 10% to 40%, expressed in terms of percentage of floor area). For a well-insulated house (U = 0.31 W m-2 K-1), the glazing U value has no effect upon the room air temperature if the glazing area is small (less than 10%). The position of the insulation on the exter nal surfaces is more effective in reducing large in-room air temperatu re. Finally, for an insulated house, we recommended glazing is 30%, 20 %, and 10% for cold-sunny, cold-cloudy, and composite climates, respec tively.