Thermal environment optimisations of cave dwellings for the elderly in heating season among cold regions of China

Abstract

In the vast developing world represented by China, the unsatisfactory thermal and humidity conditions among rural built environments are extremely harmful to the elderly-health in cold regions. The cave-dwellings maintain competent thermal stability, while with current refurbishment still cannot meet their relatively demanding thermal comfort needs. In fact, few studies have highlighted the optimisation effect of passive designs engaging various buffer spaces. Through experimental field measurements of representative cave dwelling and numerical simulations based on the DesignBuilder tool for the corresponding retrofit prototypes, this study investigated in detail the hidden correlations between key buffer space design variables (sunroom, under-eave gray space, courtyard, etc.) and the resulting indoor thermal and humidity performances for the elderly. The results of the study showed that:1) The average winter room temperatures of both heated (11.2 ± 1.5 °C) and unheated (6.4 ± 2.7 °C) rooms in traditional cave-dwellings fail to meet the recommended standard by World Health Organization (18 °C) and the Chinese national standard (16 °C–24 °C). 2) For living track temperature steps reduction, the southern sunroom has obvious impact (mostly <10 °C), while enclosed courtyards with glass-top can even enhance such performance (mostly <5 °C). 3) For boosting indoor temperatures in winter, sunroom with enclosed courtyard are most effective in unheated and heated conditions. As the first systematic work to reveal the thermal-enhancing effectiveness of the south-facing buffer space for cave-dwellings in cold climates, the research findings can assist optimizing-retrofitting for cave-dwellings among similar climatic regions globally.