Effectiveness of passive design measures under future climate change for residential building in a humid subtropical region

Abstract

Subtropical regions have suffered from the severe effects of climate change over the past few decades. To counteract the rising ambient temperature, indoor cooling demands have also risen. The high annual energy consumption of buildings is often offset by the adoption of passive cooling strategies, which are adapted to preserve indoor comfort. Passive design measures (PDM) are crucial in reducing buildings' annual energy consumption. Its continued efficacy in the face of future climate change, however, depends critically on the careful selection of appropriate passive design measures. This research simulates the effects of five passive design measures (front green wall, ventilation 24 hours, window louvers, combination of window louvers and overhangs, and C8 which is the combination of front green wall, night ventilation, and shading devices) for a house in the subtropical city Islamabad. Energy simulations are computed for typical metrological/base year as well as future weather files for 2050 and 2080. Results reveal that the combination of a front green wall (FGW), shading, and night ventilation (C8) has the maximum capacity to reduce the effect of future energy consumption. As the climatic conditions get more extreme in the future, C8 gives more effective results. C8’s annual energy consumption results reduces by 25%, 27%, and 30% when compared to non-passive results of TMY, 2050, and 2080 weather files respectively. Whereas, the effect of ventilation decreases, as it provides a 5.8%, 3%, and 2.7% decrease in annual mean energy consumption when compared with non-passive results of TMY, 2050, and 2080 results respectively. In the last section, the impact of different components of the most optimum PDM combination was also analyzed. Optimum values of leaf area index, louvers blade width & thickness & shading area all contributes to give overall better results.