Analysis and Optimization Strategies for the Summer Indoor Thermal Environment of Existing Rural Houses in Relocated Rural Settlements

The thermal performance of buildings in relocated rural settlements is closely associated with the enhancement of residents’ living quality and the attainment of the Sustainable Development Goals (SDGs). This study investigates Zhufang New Village in Nanchang City, Jiangxi Province, utilizing a multi- dimensional analytical framework that integrates climatic conditions, spatial morphology, architectural layout, and construction methodologies. Field investigations and empirical data analysis were conducted to analyze the summer thermal performance of representative rural houses, with the objective of elucidating heat transfer mechanisms and identifying key limiting factors. Drawing upon these findings, targeted optimization strategies for thermal performance were formulated. The findings reveal that: (1) Disruptions in hygrothermal regulation substantially degrade the indoor thermal environment, as evidenced by mean temperatures (29.9℃) that surpass the upper limit of the national standard by 1.9℃. The peak temperature recorded on the second floor (31.2 °C) approaches the thermal tolerance threshold (33 °C), while spatial thermal comfort compliance ratios demonstrate marked spatial variability; (2) Interfacial thermal bridging and asymmetrical heat flux distribution generate dynamic thermal stresses. Temperature differentials (ΔT ≥ 2.3 °C) are observed at the roof-balcony junction, whereas radiative heat gain through the east wall produces a daily temperature fluctuation of 4.1 °C. The implementation of thermal inertia mechanisms effectively mitigates humidity oscillations within ±8%; (3) Validation through a climate-adaptive model (25.6–27.6 °C) demonstrates that enhancements to roof U-values, enclosed balcony reconstructions, and composite structural modifications to the east wall achieve a significant reduction in temperature amplitude and an increased proportion of thermal comfort hours.