Indoor thermal environment of Mongolian traditional mobile housing used as urban habitat in winter

Abstract

Gers, which are traditional mobile tents used by nomadic society of Mongolia, are currently used for urban habitats, and pollutants emitted from coal stoves used in urban gers are one of the major causes of air pollution in Ulaanbaatar in winter. Replacing coal stoves with low-emission heating devices in ger housing is, therefore, a pressing issue. Nevertheless, fuel stoves have been used in gers for generation since the nomadic period, and a previous study reported that urban ger residents were generally satisfied with the indoor environment heated by a coal stove. Against this background, the present study aimed—based on field measurements—to characterize the spatial and temporal characteristic of the thermal environment within gers heated by coal stoves, to provide insights for smoothly shifting the current stoves to electric heating. The measurement results showed diverse daily fluctuations of indoor temperature among days and households dominated by the unstable heating power of stoves, which is influenced by the occupants' style of coal input. The indoor air temperature occasionally resulted in outliers beyond the comfort temperature range. By contrast, the operative temperature was above the lower limit of the ASHRAE comfort range for over 70% of the time owing to the direct radiation of stoves, highlighting that the current design of gers and the use of fuel stove are reasonable to achieve a comfortable indoor environment in winter under the conditions of nomadic mobile dwellings, which necessitates a lightweight envelope with poor insulation performance.