Session: Research Posters

Paper Number: 109096

109096 - Double Solar Screens Installed on Window With Different Opening Sizes 

The external shading devices, such as solar screens, are boards that are made of wood, metal, or gypsum and punched to create a pattern of holes of decorative shapes. The heat gain through the window is influenced by heat transfer coefficient and air temperature at the indoor and outdoor sides of the window, the thermal and optical properties of window . High outdoor air velocity increases the heat transfer coefficient, and thereby the heat gain. Additionally, the outdoor shading devices add an additional astatic value to the building . Research accomplished before shows a positive influence of the shading devices on heat gains and daylighting performance in hot climate regions. The results show that the indoor air temperature is reduced to acceptable level, and the visual environment is substantially improved. Two white color solar screens are installed on the external side of a double-glazing window. The height and width of the solar screens are 135 cm and 290 cm, respectively, and their thicknesses are 0.5 cm. The distance between the first screen and the windows and the first screen and second screen are 10 cm. The building is located in Kuwait City (N29^o 18' 06", E47^o 52' 44") and the window is facing the west direction. Three circular hole diameters of the solar screen are considered: the small (10 cm), medium (12.5 cm), and large (15 cm). The distance between the centers of the holes is 20 cm for all arrangements. The illuminance level in the indoor space and heat flow through the window are measured. Nine solar screens arrangements have been considered: three single solar screens: small, medium, large, and six double solar screens: two smalls, two mediums, two larges, small and medium, small and large, and medium-and large. For comparative purposes, the measurements are done for a window without the solar screens.

Windows admit direct sunlight and diffused skylight into a building that create a visually comfortable and productive environment for the occupants. However, an excessive amount of daylight causes strong light contrast and glare that lead stress and fatigue. Therefore, windows are internally or externally shaded to reduce and diffuse the daylight. In present research, two perforated solar screens are installed on the external side of a window. Both solar screens have circular hole perforations but with different diameters. The objective of the solar screens is to reduce the level of sunlight entering the indoor space to an acceptable one. The effect of the solar screens on the illuminance distributions and heat gain to the indoor space is presented. Three diameters of the holes are evaluated: small, medium, and large. The heat flow at the indoor surface of the window, the air temperature, solar radiation, and illuminance level are measured. The effects of the screen’s holes diameter on the heat flow and illuminance distribution are presented, and the optimum holes diameters for solar screens are determined.

Presenting Author: Esam Alawadhi Kuwait University

Presenting Author Biography: Esam M. Alawadhi is professor of Mechanical Engineering at Kuwait University. He earned his Doctor of Philosophy in May of 2001 from Carnegie Mellon University, USA. His research focuses on thermal management of electronics devices, energy for buildings, fluid flow stability, and phase change heat transfer. He had the engineering research production award, Kuwait Foundation for Advancement Science, in October of 2010. He is the author of Finite Element Simulations Using ANSYS book published by CRC Press, and co-author of Eco-efficient Masonry Bricks and Blocks: Design, Properties and Durability book published by Woodhead Publishing. He published more than thirty papers in peer reviewed international journal, and presents more than thirty research outcomes in international conferences.

Authors:

Esam Alawadhi Kuwait University