Investigation of Indoor Asymmetric Thermal Radiation in Tibet Plateau: Case Study of a Typical Office Building

Meilin Wang,Pengyuan Shen

doi:10.3390/buildings12020129

Abstract

The unique climate in cold plateaus leads to long and cold winters, which result in the characteristics and creation of an indoor thermal environment different from that of plain areas. However, there is a lack of detailed research on and evaluation of indoor temperature distributions. This study took an office building in Lhasa as an example to study the indoor non-uniform temperature distributions with radiator and solar radiation. The indoor and outdoor thermal environment parameters were tested. Next, a numerical model was established and verified. On a typical winter weather day, although the average indoor air temperature and radiation temperature in Lhasa are higher than those in Beijing (both are cold areas), the temperature in both is lower than comfortable levels. The indoor vertical air temperature differences are below 3 °C, with a 5% dissatisfaction most of the time. Solar radiation and radiators seriously affect the uniformity of the indoor thermal environment. The radiation asymmetry in Lhasa is significant, and the maximum radiation temperature asymmetry can reach 8.73 °C. In addition, the setting of north-facing windows should be avoided as far as possible in Tibetan areas. Suitable design and evaluation standards should pay attention to the obvious phenomenon of uneven indoor temperature distribution.

Highlights

Tibet is called the “Roof of the World” and the “Third Pole of the Earth” [1] due to its average altitude of over 4000 m and unique ecological features [2]
According to the measured data of the office room, the outdoor air temperature in Lhasa ranged between 0.05 °C and 17.96 °C, and the indoor air temperature between 17.01 °C and 24.05 °C
According to the simulation results, the air temperature had obvious stratification in the vertical direction, and the temperature rises with the increase in height, which had the same trend as the internal wall temperature

Summary

Introduction

Tibet is called the “Roof of the World” and the “Third Pole of the Earth” [1] due to its average altitude of over 4000 m and unique ecological features [2]. The mean indoor air temperature of the Tibet Plateau in winter is very low, only 5– 12 °C for rural buildings [4] and 3.8–7.8 °C for traditional houses [5] in Lhasa; 2.8 °C in Kangding [6]; 4.16 °C in Nyingchi [7]; 2.5 °C in Gannan [8]; and 6 °C in Qamdo [9]. The perception of discomfort can be attributed to the special characteristics of solar radiation, sky background temperature, and outdoor temperature in Tibet, which makes the internal surface temperature vary greatly between walls and leads to variations in radiative heat exchange differences between the human body and each internal surface. Asymmetric radiation is an obstacle to achieving satisfying indoor thermal comfort in Tibet

Methods

Results

Discussion

Conclusion