Wind-driven rain effects on annual energy use of low-rise residential buildings in the hot-summer and cold-winter region: A numerical simulation

Wind-driven rain (WDR) significantly impacts the hygrothermal performance of building envelopes in the hot summer and cold winter (HSCW) region. However, research on this topic concerning low-rise residential buildings is lacking. This study utilized the WUFI Plus software to conduct numerical simulations exploring the influence of WDR on the indoor hygrothermal environment and annual air-conditioning energy consumption of flat roof (FR) and sloped roof (SR) low-rise residential buildings in four microclimate subregions of the HSCW region. A coupled model integrating WDR-envelope heat and moisture transfer with air-conditioning energy consumption was developed and validated. The findings indicate that SR buildings exhibit better hygrothermal stability compared to FR buildings. WDR leads to a decrease in summer cooling energy consumption and an increase in winter heating energy consumption, with more pronounced effects on FR buildings. In summer, WDR lowered peak indoor temperatures of FR buildings by 0.6–1.8 °C across the four representative cities. Across the HSCW sub-climates, cooling energy consumption decreased by 4.6%–11.5% for FR buildings and 3.8%–10.2% for SR buildings; conversely, heating energy consumption rose by 1.4%–3.4% and 1.2%–2.8%, respectively. This study provides theoretical and practical insights for climate-adaptive energy-saving design of low-rise residences in the HSCW region and contributes to building carbon reduction efforts.