An experimental study on the indoor thermal environment in prefabricated houses in the subtropics

• The air temperature inside the experimental PH was very high at daytime in summer, but very low at nighttime in winter.
• The variation of the air temperature inside the PH appeared synchronized with that of outdoor air temperature at daytime in summer.
• Air temperature stratification inside the PH was observed in both winter and summer.
• External roof temperature was lower than outdoor air temperature at nighttime.

Temporary prefabricated houses (PHs) can be effective in providing disaster victims with a temporary living place quickly whenever there is a natural disaster, and are also widely used in providing construction workers with living places. However, there are very limited studies on indoor thermal environment inside PHs, with their inadequacies. Therefore, an experimental study on the indoor thermal environments in an experimental PH located in the subtropics is reported in this paper. The study results suggested that at closed door and window situation, the air temperature inside the experimental PH was very high at daytime in summer, but very low at nighttime in winter. In addition, the variation of the air temperature inside the PH appeared synchronously with that of outdoor air temperature at daytime in summer, suggesting insignificant thermal mass of envelope to store solar heat gain. Furthermore, in both winter and summer, indoor air temperature stratification was observed. At daytime, indoor air temperature was increased with the height but at nighttime, decreased with the height. Finally, external roof temperatures in both winter and summer time were lower than outdoor air temperature, reflecting sky cooling effects for the experimental PH. The measured thermal environments inside the experimental PH, clearly demonstrated that the thermal environments inside PHs are highly unacceptable for long term occupation and that appropriate measures should be taken to improve the thermal environments in PHs.