Assessment of the Setback Regulations’ Impact on The Quality of the Indoor Environment and Enhancement Strategies in Bethlehem-Palestine

Abstract

Urban context has a significant impact on energy consumption, daylighting intensity, in multi-story residential buildings which represent the largest construction sector in Palestine. The relationship between building blocks and indoor environment performance has become increasingly important. Because the building regulations especially setbacks regulations are the primary regulator of this relationship, this thesis examines the interaction between buildings' performance and setbacks regulations in residential B-Zone in Palestine. The study depends on quantitative and qualitative methods to achieve the research objectives. Simulation results were employed to investigate the impact of current setbacks regulations by using Design Builder software, then discusses alternative strategies for reducing energy consumption for lighting, heating, and cooling activates. Analysis of the most common residential building prototypes was carried out in terms of apartment area, number of floors, common residential spaces and their characteristics and the number of apartments on each floor to help in the assessment and proposing alternative phases. The simulation work was conducted along two consequent phases; firstly, simulating the current situation of the residential urban context with existing setbacks regulations and their impact on the natural daylight and thermal energy performance, and secondly optimizing these parameters by testing various alternatives. To further examine how the local setback affects the provision of daylighting and energy savings, both urban and building levels parameters were considered. Urban factors include the external blocks and the relations to each other. On the other hand, building level factors like window to wall ratio (WWR) and shading devices were included. In the assessment phase, the results show that existing setback distances in residential B-Zone are not sufficient to provide an acceptable level of daylighting and to enhance the thermal energy consumption inside residential spaces. In the optimization phase, the study found that, 10m of building separation is the minimum distance to obtain an acceptable level of daylighting and minimize total energy consumption to enhance the building performance. The optimal setback distance was in all cases higher than the current distance and often reached twice the existing distance. At the building level, the optimization process indicated as for windows characteristics, WWR has a significant impact on daylighting availability and on heating energy consumption at regulated setbacks distance. Optimal WWR, especially on lower floors, was higher than WWR in the current housing projects. For example, the optimum WWR for the living room in the north-oriented street was 60%, 40%, 20%, and 20% in the first, second, third, and fourth floors which are higher than the existing ratio of 22.70% on all floors. In addition, shading systems especially outside blind which is used in hot summer is the ideal strategy to be implemented to block direct sunlight in summer to reduce cooling consumption by about 4% to 35% and admit natural daylight and solar radiation in winter in all urban context cases.