Summer Thermal Challenges in Emergency Tents: Insights into Thermal Characteristics of Tents with Air Conditioning

Abstract

Emergency tents face challenges in harsh weather conditions and sometimes require the use of air conditioning for indoor thermal environment control. However, their lightweight structure makes their control methods different from conventional buildings. This study focuses on the indoor thermal environment and thermal comfort of air-conditioned tents during summer. Through experimental measurements, this study captures the distribution of air temperatures and inner surface temperatures within a tent, thus providing an understanding of the characteristics of indoor thermal environment in air-conditioned settings. Additionally, the numerical simulations conducted using the ANSYS FLUENT 2021 R1 calculate the Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD), thus contributing to a detailed analysis of the indoor thermal comfort states. The experiment revealed that the mean radiative temperature (MRT) inside the tent can exceed the air temperature by more than 10 °C. Even when the air temperature is around 26 °C, the excessively high MRT can cause occupants to feel uncomfortable, with the PMV exceeding 1.4 and the PPD surpassing 50%. Furthermore, the high MRT results in an increased demand for cooling airflow, with the cooling loss through gaps becoming a significant part in the cooling load. To ensure a comfortable thermal environment, the air-conditioning set temperature needs to be adjusted according to the weather conditions. For instance, even at the same air temperature of 35 °C, when solar radiation increases from 400 W/m2 to 1000 W/m2, the set temperature needs to be reduced from 24.7 °C to 20.7 °C. The findings of this study provide an important reference for establishing summer air-conditioning strategies for emergency tents.