Impact of the design of urban block on buildings’ indoor daylight and energy loads in semi-arid regions

Abstract

It has been proven that designing sustainable buildings starts from early stages of urban design. The design of urban blocks, specifically, is deemed one of the pragmatic approaches of sustainable urban design. Studies have focused on the impact of urban block design and regulation on the outdoor thermal comfort in the semi-arid regions. However, limited studies have been found in the semi-arid regions, which examined that impact, on the indoor behaviour of buildings (specifically, the daylight quality and energy performance). Further, heating load is neglected in most studies of the semi-arid regions in which the focus is only on the cooling load reduction. The study has focused on two parameters of urban block distribution, which are the surface-to-volume ratio of blocks and their orientation with the consideration of both heating and cooling loads of buildings. In Duhok (a semi-arid city in the Kurdistan region of Iraq), daylight quality and energy consumption of various types of residential blocks have been observed using dynamic simulation. The results propose that there is a substantially higher energy demand for heating than cooling, providing attention to the heating load in semi-arid regions. Reasonably, because of the high U-values of buildings in Duhok. The findings also suggest that changing blocks’ orientation can alter the total energy consumption by 8%. With regards to the surface-to-volume ratio (S/V), an increment of 15% of overall energy consumption is noticed after doubling the ratio (S/V), though the research reveals the opportunity of decreasing energy consumption with the rise of the S/V through passive design strategies of urban blocks. Based on the results, recommendations are given for revising the design of current/future residential urban blocks to maximise indoor daylight quality with a higher S/V and more energy saving in these regions.