Performance of Solar Window Film with Reference to Energy Rationalizing in Buildings

Abstract

In the last decades the growing need for comfort conditions in residential buildings and the severe summer conditions typical of Mediterranean climate have led to an ever-increasing request for the installation of air-conditioning systems. This has led to rising consumption of electricity and has influenced the cost of electricity and the need for more power plants. Furthermore, the CO2 equivalent emissions’ factors from electricity will rise. In this study, two wooden cabinets (cabinets A and B) were built to be a model for two rooms in a building in city of Duhok, Iraq. These cabinets were of double-glazed window, insulated by air. Solar control window film (SCWF) has been attached on the window of one of the cabinets (cabinet B). Measurements of the following physical variables parameter were performed, outside and inside the cabinets: solar radiation (SR), temperature (T), and relative humidity (RH). The measurements were done in two different cases: one, when the surface color (SC) of both cabinets was white and, for the other, when the SC was black.

In this study, we investigate the performance of solar control window films based on a clear double glass window for one of the cabinets. The study is generalized for a large-scale practical case if a window film of similar properties is applied to the windows of rooms in a building in Duhok, Iraq. Thermal conductivity of each glass, wood, and SCWF has been measured. The absorbance and transmittance of the window glass as well as the solar control window film have been measured by using the UV, VIS, and NIR spectrophotometer instruments. It was found that the temperature of cabinets depends on surface color (SC) of the cabinet. In case of white surface (WS) cabinet, the temperature of cabinet was approximately 10 °C lower than black surface (BS) of cabinet, while the temperature difference between cabinet A [CA] and cabinet B [CB] was approximately equal to 5 °C. In case of black surface) BS) cabinet, the temperature difference between CA and CB was about 7 °C. It was observed that the blocking capacity of thin solar control film depends on the time of day and weather conditions. Utilizing window films in a building will lead to reduction in heat gain from solar radiation, i.e., it will reduce the building cooling load in summer, or using the solar control window films in buildings will lead to reduce the electrical energy consumption in summer. Also, this will contribute in reducing CO₂ and other greenhouse gases (GHG) emissions that cause global warming in the world. Further advantages in using such film are the reduction of glare, heat, and UV.