This paper focuses on thermal environmental conditions in the stone dwellings of a Tibetan village in Danba County, Sichuan, China, in winter. During the study, field measurements and subjective survey studies were collected, simultaneously, to provide a comprehensive understanding of the thermal comfort conditions that were experienced by residents in cold rural areas of Sichuan. Subjective surveys involved questions about thermal comfort perceptions and acceptability in cold conditions. The status of thermal comfort and characteristics of indoor environmental qualities were investigated in the study. The majority of survey participants (47% and 74%) voted as “slightly cool” for temperature, and “slightly dry” for humidity in the studied typical winter days, respectively. The available adaptive opportunities for the residents were investigated through the survey studies. Adjusting clothing, drinking hot beverages, blocking air infiltration through windows, and changing activities were the most common adaptive measures. An adaptive coefficient ( ) was determined based on adaptive predicted mean votes (aPMV) models using least square methods to assess the different adaptation measures in the region. Findings of this study provided a valuable reference for thermal comfort adaptations in cold climates, where limited adaptive opportunities were available due to the low standard of living.
Urban residents are suffering from serious thermal stress resulting from urban heat island and global warming. Investigators have explored several methods to address this issue. Vegetation, especially trees, were found to play a vital part in urban environments. It produces a cooling effect by reducing temperature and radiation levels. To find thermal performances of trees in detail, this study physically measured two urban parks during August 2019 in a satellite city of China regarding their thermal environments relevant to tree planting indices. There were three planting indices used, sky view factor, leaf area index and enclosure area. Through associating them with thermal indicators by linear regression, all of the indices were confirmed to have significant thermal effects. Every 0.1 increase in sky view factor resulted in an increase of 1°C air temperature, 0.16 m/s air velocity, 40 W/m2 solar radiation level and 1.6°C mean radiant temperature. Same effects were found in nearly 0.4 leaf area index decrease and approximately 20 m2 enclosure area increase. These results provide very optimistic directions for future urban forestry planning and landscaping.
Located on the east side of China’s Qinghai–Tibet Plateau is the Western Sichuan Plateau, the courtyard adopts a passive design to withstand the harsh climate in cold areas, and its internal thermal environment has a direct impact on the productivity and activities of the residents. This paper takes a plateau village (3500 m above sea level) beside the Sichuan–Tibet line as the research area, and selects four typical local courtyard layouts and an outdoor reference point for the measurement and comparison of the thermal environment. By comparing the measured parameters inside and outside the courtyard, and the correlation analysis, it was deduced as follows. (1) In the cold winter, traditional plateau residential courtyards can create a stable internal micro-climate, but the cold resistance of the courtyards is closely related to its layout. (2) Except for wind speed, other thermal environment parameters of the courtyard are all affected by solar radiation (3) The correlation analysis of the various environmental parameters and physiologically equivalent temperature (PET) showed that the correlation coefficient between the mean radiation temperature (Tmrt) and all courtyard PET values is <0.0001, showing a significant correlation. The indicators of mean temperature radiation are mainly affected by the temperature and the wind speed; furthermore, the temperature and solar radiation are positively correlated, which confirms that the solar radiation and wind speed within the courtyard are the main factors affecting the internal thermal environment in the courtyard. (4) Feedback the courtyard layout problems through the difference in the thermal environment parameters within different courtyards, and then determine some shortcomings in the current courtyard layout design. The inferences drawn from this work will provide a scientific basis for the design, layout, and construction of courtyards in other cold plateau areas.