A Study On Building Solar Absorption And Effects On External Walls

The rapid growing of the world’s energy consumption has already raised concerns over supply difficulties, exhaustion of energy resources and heavy environmental impacts (ozone layer depletion, globalwarming, climate change, etc.). Growth in population, increasing demand for building services and comfort levels, together with the rise in time spent inside buildings, assure that the increasing trend in energy demands will continue in the future. For this reason,today, energy efficiency in buildings is a prime objective for energy policies at regional, national and international levels.The principal concern of this paper is to use solar energy to decrease the energy consumption of buildings by using CFD Modeling and 3D simulation. In this regard, by using solar absorption coefficients of different colors, the best color for the external walls of Mashhad’s buildings was chosen to reach the most optimal temperature on cold and warm days simultaneously. Solar load was calculated with the help of a solar calculator based on the geographical information of Mashhad. In addition, CFD simulations of the turbulent flow field were carried out using thestandard k–ɛ turbulence mode, and finally internal temperatures in the range of solar absorption coefficients (0.4 to 0.9) were determined. Using this information, the color which decreases the temperature by 1.5 Celsius degrees on warm days and increases it by about 1 Celsius degree on cold days was chosen,entailing a significant reduction in the energy consumption of buildings. This paper shows us that we can estimate suitable colors for other regions of the world depending on their geographical information and share of solar energy.

Keywords:

solar absorption coefficient , solar energy , CFD modeling , 3D simulation , building energy consumption