Design Research on Improving the Environmental Performance of Rural Dwellings in China’s Hexi Corridor with Seasonal Room Rotation

Since the reform and opening-up, China’s urbanization has progressed rapidly, leading to a continuous migration of rural populations to urban areas. This population outflow is particularly pronounced in the economically less developed Northwest China, triggering a series of issues such as rural vacancy and the idling of residential resources. Against this backdrop, there is an urgent need for scientific methods to guide the renewal design of rural residences, aiming to enhance living comfort, optimize spatial utilization efficiency, and curb rural decline. Although existing research often explores resource utilization strategies at the village level, systematic studies focusing on the individual building scale remain relatively scarce. This study targets rural residences in the Hexi Corridor region. It systematically identifies the “Seasonal Room Rotation” living pattern formed under the context of population contraction and analyzes the “conflict between solar gain and overheating” phenomenon caused by the extreme climate. By integrating architectural characteristics and psychrometric chart analysis, suitable passive design strategies are summarized. Furthermore, based on objectives for indoor light environment and thermal comfort, a genetic algorithm is employed to conduct multi-objective optimization of various building parameters. The results indicate an inherent contradiction in achieving both “warm in winter and cool in summer” within a single room. However, by functionally differentiating building spaces according to their season of use—designating separate “Winter Rooms” and “Summer Rooms”—both winter thermal insulation and summer cooling performance can be systematically enhanced. The research further proposes key design parameters applicable to this new “Seasonal Room Rotation” living pattern, including courtyard form, building height, window-to-wall ratio, and shading component dimensions. This elevates the seasonal adaptation strategy from an internal room-level compromise to a holistic building-level allocation of spatial resources. This study constructs a design methodology for enhancing the green performance of rural residences amidst population contraction. It simultaneously optimizes indoor comfort and spatial utilization efficiency, offering a highly operable new design paradigm for the green renewal of rural homes in complex climatic conditions.