Evaluation of the Urban Compactness Indexes in Feasibility of Use of Solar Energy Potential using GIS (Case Study Ahvaz 4 Region)

Emission reduction of carbon dioxide and its impact on global warming process is one of the most important results in the use of renewable energy sources. In urban areas, solar systems stationed on building roofs are the most appropriate utilization method of stable source of solar energy. Urban compactness is a major urban form parameter that affects the accessibility of solar renewable energy in the built environment, so it is essential that the effects of urban compactness on buildings utilization of solar energy, be surveyed. The aim of this study is the evaluation of solar energy potential in urban areas and determination of the relation between urban compactness indicators and solar energy potential in the local scale. In this study, the annual solar radiation modeling for each of the building surfaces of the study area, over one year period, was performed using the Solar Analyst model. On the other hand, the relation between various compactness indicators including site coverage, plot ratio, volume-area ratio, Entropy, population density and building density with Annual solar radiation received by the study area was explored and using least squares regression model, the relationship between the solar radiation and urban compactness indicators was determined. Also potential of using two types of active solar systems including Building Integrated Photovoltaic Systems (PV) and Solar Thermal Collectors (STC) was evaluated. According to the results, the annual solar irradiation increase from 507 (in compression areas) to 741 (in scattered areas) Kilowatt hours per square meter. Volume-area ratio shows the highest determination coefficient, R2 equal to 0/805 with annual solar radiation. Also in the study area, the building roofs potential for the development of PV systems much more than STC systems, influenced by the degree of urban compactness.