Thermal comfort and energy-saving retrofits: An empirical study in high-altitude regions

With the intensification of global warming, issues related to human thermal comfort have become increasingly prominent. In Xizang's extreme climate, indoor thermal comfort faces significant challenges. This study conducts an empirical investigation of an office building in Lhasa, employing on-site surveys, questionnaires, and field measurements to evaluate and validate the effectiveness of passive retrofit strategies in improving indoor thermal environments and thermal comfort. The results indicate the following: (1) The synergistic application of passive solar heat gain and high/low-heat-capacity materials is the most suitable passive strategy for Lhasa; (2) optimizing external wall insulation, window materials, and increasing the window-to-wall ratio significantly enhances indoor thermal comfort levels but requires further integration with humidity control and thermal storage strategies; (3) for the retrofitting of envelope structures on different orientations and floors, differentiated strategies should be adopted based on local climate conditions and surrounding environmental characteristics to optimize thermal performance; (4) Retrofitting existing buildings should address both winter heat gain needs and indoor humidity and ventilation, achieved through indoor greenery and optimized ventilation strategies for precise temperature and humidity control. This study provides essential references and optimization strategies for the passive retrofitting of office buildings in high-altitude, cold regions.