Field study of a thermal environment and adaptive model in Shanghai

A long-term field investigation was carried out in naturally ventilated residential buildings in Shanghai from April 2003 to November 2004. A total of 1,768 returned questionnaires were collected in the study. This study deals with the thermal sensation of occupants in naturally ventilated buildings and the change in thermal neutral temperature with season. The range of accepted temperature in naturally ventilated buildings is between 14.7 degrees C T(op) and 29.8 degrees C T(op). The results also report the findings of the adaptive comfort model in Shanghai that determines the adaptive relationship of neutral temperature with outdoor air temperature. A long-term field study was carried out in residential buildings in Shanghai to find the relationship between thermal sensation, indoor neutral temperature and outdoor temperature. This paper presents findings of thermal comfort and discusses the more sustainable standard for the indoor climate of residential buildings in Shanghai.     

Study on dynamic characteristics of natural and mechanical wind in built environment using spectral analysis

What are the differences and similarities between natural and mechanical wind in built environment? This is an interesting question that has not been well answered yet. In the paper, spectral analysis is applied to study the dynamic characteristics of natural and mechanical wind in different conditions. The results show that in the frequency region sensitive to human sensation, the power spectrum characteristics of natural wind and mechanical wind have obvious differences as well as interesting connections. The power spectrum exponent (β$\beta$ value) of natural wind is between 1.1 and 2.0 in the human sensitive frequency region, while the value of mechanical wind is between 0 and 0.5 around the air supply outlet. With the diffusion of mechanical wind, β$\beta$ value will increase gradually and reach the value of the typical natural wind when the mean velocity is lower than 0.25 m/s. Finally, the influence of spectral characteristics on human sensation for airflow is discussed.     

Assessment of the microclimatic and human comfort conditions in a complex urban environment: Modelling and measurements

Several complex thermal indices (e.g. Predicted Mean Vote and Physiological Equivalent Temperature) were developed in the last decades to describe and quantify the thermal environment of humans and the energy fluxes between body and environment. Compared to open spaces/landscapes the complex surface structure of urban areas creates an environment with special microclimatic characteristics, which have a dominant effect on the energy balance of the human body. In this study, outdoor thermal comfort conditions are examined through two field-surveys in Szeged, a South-Hungarian city (population 160,000). The intensity of radiation fluxes is dependent on several factors, such as surface structure and housing density. Since our sample area is located in a heavily built-up city centre, radiation fluxes are mainly influenced by narrow streets and several 20–30-year-old (20–30 m tall) trees. Special emphasis is given to the human-biometeorological assessment of the microclimate of complex urban environments through the application of the thermal index PET. The analysis is carried out by the utilization of the RayMan model. Firstly, bioclimatic conditions of sites located close to each other but shaded differently by buildings and plants are compared. The results show that differences in the PET index amongst these places can be as high as 15–20 ^°C${}^{°}\mathrm{C}$ due to the different irradiation. Secondly, the investigation of different modelled environments by RayMan (only buildings, buildings+trees$\mathrm{buildings}+\mathrm{trees}$ and only trees) shows significant alterations in the human comfort sensation between the situations.     

Measurement and simulation of the thermal environment in the built space under a membrane structure

This paper presents a study to clarify characteristics of the summer thermal environment in an actual membrane structure with a semi-closed space underneath by using field measurements and simulations. The first part of this paper describes the following findings from the field measurements conducted during a summer period: (1) the solar transmission through the membrane had a greatest impact on the thermal environment in the living space under the membrane structure during the daytime; (2) the mean radiant temperature (MRT) at the central part of the living space went higher than the air temperature due to heat storage in the ground and walls of surrounding buildings where radiation cooling to the sky was obstructed by the membrane. In the second part of the paper, a 3D CAD-based simulation tool (called the thermal environment simulator) developed by the authors' group was used to simulate the thermal environment in the test membrane structure. A comparison between the measured and simulated surface temperature of the membrane was carried out. As a result, it was found that the simulated results agreed well with the measurement data. In addition, the following subjects were discussed using the simulation tool: how the thermal environment under the membrane is influenced by changing the solar transmittance and absorptance of the membrane or changing the ground surface materials. Simulation results show that the simulation tool is able to provide a quantitative prediction and evaluation of the thermal environment in the living space under the membrane structure in terms of the surface temperature and mean radiant temperature distribution.     

西安某高校学生公寓冬季室内热环境实测分析

以西安某高校学生公寓宿舍作为测试对象,采用现场测试和问卷调查的方法从主观和客观两个方面研究了公寓室内热环境的状况,为今后学生公寓室内热环境的评价和改进提供依据。     

The influence of wind flows on thermal comfort in the Daechung of a traditional Korean house

Daechung, a semi-open space with wooden floor located between the front and backyards of traditional Korean residences, is well known as a cool space in summer due to cross-ventilation, but it has not yet been scientifically explained thoroughly. The purpose of this paper is to characterize the wind flow measured at a Daechung to interpret the effects of the wind characteristics on thermal comfort. We measured 10-Hz turbulence data at the Daechung and partitioned the wind vector into two directions (i.e. backyard to Daechung and front yard to Daechung). Interestingly, the wind from the cool backyard flowing through the Daechung was of less frequency and shorter duration but had higher velocity compared to wind from the opposite direction, which can provide thermal comfort to the dwellers. We suggest that the wind characteristics were determined by various aspects of the house's design, such as its location and the degree of enclosure in front and backyards. The results show that traditional Korean house made use of a natural ventilation system during the summer. The principles of this system could be helpful in constructing environmentally friendly and sustainable residences.     

大空间建筑室内热环境CFD模拟中壁温及室温的求解

应用PHOENICS软件模拟某体育馆的室内热环境,将壁温作为模拟的第一类边界条件。建立了室内表面对流辐射耦合换热方程,着重讨论了采用表面换热分析法求解表面传热系数以求解壁温的方法。因壁温计算和室温计算互相耦合,采用迭代计算的方法求解壁温和室温。模拟计算结果与实测结果基本吻合。