Effect of Building Form on the Thermal Performance of Residential Complexes in the Mediterranean Climate of the Gaza Strip

Abstract

Climate is one of the most important factors that affect both urban planning and architectural design. Energy consumption of a building is strongly related to the climatic surrounding it which has a major effect on its thermal performance. Residential buildings are considered the most architectural structures consuming energy in the world. This research comes in an attempt to study the thermal performance of residential buildings and its impact on thermal comfort. The research also seeks to study the impact of climatic factors on the urban configuration, especially with regard to the geometric shape and orientation of the housing unit. Also the research provides an overview of the residential complexes in the Gaza Strip and their design especially with regard to their form and orientation. In this context, the research assumes that the geometric shape and orientation of the housing unit as well as the form and orientation of its urban configuration significantly affects the thermal performance of the housing unit, and thus the heating and cooling loads. Hence, the research seeks to evaluate the thermal performance of different geometrical shapes and orientations of the housing unit and within different urban configurations. The research is carried out using the analytical approach by using the computer programs ECOTECT and IES. The research aims to reach to the best possible configurations which present the high thermal performance in order to use it in residential buildings in the Gaza Strip. The results indicate significant thermal effects due to the form’s proportions and orientation. The research concluded that the surface to volume ratio is considered the main responsible for the thermal response in different geometric shapes. The energy consumption increases at the same rate of increasing in the surface to volume ratio (S/V) in the Mediterranean climate of the Gaza Strip. About 39% of energy consumption can be reduced by choosing the optimum width to length ratio (W/L) which is 0.8. The roof to walls ratio seemed to have a great influence on the thermal response. Using the (roof/ walls) ratio which ranges between 0.4 to 0.6 is more preferable for both cooling and heating requirements. The horizontal arrangements of residential apartments is better thermally than the vertical arrangements of the same (S/V) ratio. Convex shapes such as the court, L and U shape can be used as a more preferable option for building’s arrangements than the rectangular shape of the same (S/V) ratio. A spacing ratio (L1/L2) equals 0.1 and aspect ratio (H/W) equals 0.5 is the preferable option in the (E-W) street in the Gaza Strip. However, the more preferable option in the (N-S) street has a spacing ratio (L1/L2) equals 1.2, and aspect ratio (H/W) equals 4. Therefore, the research recommends to apply passive solar design strategies, especially with regard to geometric shape and orientation in the first stage of the design process. Thermal simulation programs have to be used in order to evaluate the thermal performance of buildings. Building’s proportions have to be determined with a full understanding to their relations with the urban morphology.