LAUSR

Abstract A share of 22% for residential buildings along with 18% for commercial ones has caused the share of buildings in energy consumption to reach 40% in 2020. Focusing on energy demand reduction, this numerical study examined the effectiveness of installing PCM into building envelopes in arid climate zones based on the Koppen–Geiger classification. For this purpose, four climate zones of Dubai, Jeddah, Kuwait City and Lahore City were selected and then a 20 mm PCM layer (SP-21EK) was incorporated into envelopes to examine the effects of PCM on HVAC energy usage defining two scenarios. In the first scenario, for Dubai, Jeddah, Kuwait City and Lahore City the incorporation of PCM into the envelopes reduced the annual HVAC power usage by 55.47, 53.89, 58.86 and 53.57%, respectively. In the second scenario, HVAC power usage reduced by 2.6, 2.03, 1.99 and 5.6%. Under the best conditions and owing to using SP-21EK, CO2 emission reduced by 56.27, 44.81, 45.27 and 58.5%. Due to the PCM phase change inside the envelopes, energy consumption is reduced if PCM is selected correctly. As a preliminary choice, the apparent PCM melting temperature for Lahore City is 21–23 °C, while for Dubai this figure is 23–25 °C and PCM with melting temperature within 25–27 °C can be a good choice for Jeddah and Kuwait City.