Analysis and numerical simulation of indoor thermal environments in some university classrooms

In order to study the indoor thermal environments in university classrooms in Tianjin,a field study and a questionnaire survey for a main teaching building are carried out.First,the thermal sensations of participants in the typical classrooms are studied by 180 questionnaires.Then,based on the measured data,the temperature changes in the classrooms during a year are simulated by the DeST software.The results show that the indoor thermal environments in the northern classrooms on the first floor are better than those in other classrooms.And the measurement results accord with the simulation results.These results can be used as a reference for the study of the indoor thermal environments in other seasons.

基于被动柔顺机理的电机遥操作更换机构设计和实验

核工业热室中智能装备的驱动电机受核辐射影响易损坏,采用电机遥操作更换技术是确保热室内智能装备正常运作的关键.针对这一问题,分析电机遥操作更换设计需求,提出基于被动柔顺机理的电机遥操作更换方法;分析轴孔装配3种接触状态,建立电机垂向插配力学模型,提出动力对接策略,设计五自由度(5-DOF)空间被动柔顺机构;基于热室中遥操作机械臂的特点,设计电机遥操作更换结构和工作流程.构建实验装置,测试统计电机更换成功率和耗时,并针对电机垂向插配力学模型所预测的插配力进行检测和理论计算比对,验证电机遥操作更换结构的可靠性和电机垂向插配力学模型的有效性.电机遥操作更换技术能为热室中智能装备的自动维护提供技术支撑,也为机器人执行其他自动化装配任务提供借鉴.

Improvement of thermal performance of envelopes for traditional wooden vernacular dwellings of Tujia Minority in Western Hunan,China

Thermal performance of envelopes and indoor thermal environment were technologically improved for traditional wooden vernacular dwellings of Tujia Minority in Western Hunan, China, on the premise of protecting their conventional styles. Thermal insulation boards and wooden boards were added to the interior side of external walls of vernacular dwellings to form two layers of air cavities, so as to gain excellent thermal performance. The indoor temperature of such dwellings after reconstruction was apparently improved compared with the data before reconstruction both in winter and summer, which verified the feasibility and the effectiveness of the reconstruction technologies proposed.

Impact of cold indoor thermal environmental conditions on human thermal response

To explore the thermal responses under the non-thermal equilibrium cold environmental conditions,a laboratory study was conducted in climate chamber.The local skin temperatures and thermal sensation of 20 subjects were recorded at 10 min intervals for 90 min under air temperatures of 7.4,9.1,11 and 15 °C.The results show that both local skin temperatures and mean skin temperature decrease not only with the drop of ambient air temperature but also with the exposure time.Local thermal sensation and overall the thermal sensation have the similar temperature-varying and time-varying characteristics.Predicted mean vote(PMV) model cannot correctly predict the thermal sensation under non-thermal equilibrium cold environment.The correlation between local thermal sensation and local skin temperatures shows that thermal sensation is closely related to skin temperature.Skin temperature is an effective indicator of thermal sensation.A linear relationship model between overall thermal sensation and mean skin temperature,considering both ambient temperature and exposure time,was established in the non-thermal equilibrium cold environment,which makes the evaluation of thermal sensation more objective.

Optimal design of vegetation in residential district with numerical simulation and field experiment

Vegetation plays a key role in improving wind environment of residential districts,and is helpful for creating a comfortable and beautiful living environment.The optimal design of vegetation for wind environment improvement in winter was investigated by carrying out field experiments in Heqingyuan residential area in Beijing,and after that,numerical simulation with SPOTE(simulation platform for outdoor thermal environment) experiments for outdoor thermal environment of vegetation was adopted for comparison.The conclusions were summarized as follows:1) By comparing the experimental data with simulation results,it could be concluded that the wind field simulated was consistent with the actual wind field,and the flow distribution impacted by vegetation could be accurately reflected;2) The wind velocity with vegetation was lower than that without vegetation,and the wind velocity was reduced by 46%;3) By adjusting arrangement and types of vegetation in the regions with excessively large wind velocity,the pedestrian-level wind velocity could be obviously improved through the simulation and comparison.

Crawlspace heating system in detached house with insulated foundation

Two practical crawlspace heating systems introduced in detached houses have been chosen as a field study. One is the crawlspace warm air heating system and the other is the crawlspace hot water circulation system. Based on the field study result, by using the simulation sol, ware, THERB, the effectiveness of the crawlspace warm air heating system has been examined. The effect of the factors, such as the wind amount circulating between crawlspace and indoor space, foundation insulation condition, and heat amount into the crawlspace, on the indoor thermal environment has been analyzed. Based on these analyses, the measured crawlspace heating system can make the average temperature of the living room above 20℃. These two houses have excellent thermal environment. According to the simulating result, heat amount input into crawlspace, which can make comfortable indoor thermal environment, for every month in heating period has been roughly concluded, and they are 600 W in December and March and 800 W in February and January, respectively.

Indexes of Indoor Thermal Environment with Asymmetrical Radiant Field

The main features of top-flcor rooms with natural ventilation are identified by investigating indoor thermal environment in summer season. One is high indoor air temperature, for this reason the indoor climate is far beyond the thermal comfort standard; the other is the inhomogeneons temperature distribution of the inner wall surfaces, and high temperature of the inner surface of the roof causes much scorching to the head of occupant. This is the characteristic of such rooms. Both features mentioned above should be considered comprehensively for the evaluation of indoor thermal environment of the top-floor rooms with asymmetric radiant field. In order to characterize the indoor thermal environment of the rooms, the heat stress index, HSI and radiant heat flux reaching human head, Q_R should be introduced simultaneously as thermal indexes for the indoor climate evaluation. The application of the indexes to a topfloor room is presented and analyzed.

Outdoor thermal environmental research of the mountainous city by GIS

The study of urban outdoor thermal environment was carried out in one of the mountainous cities by using geography information system(GIS) technique which is connected with predicting and evaluating models for the outdoor thermal environment, monitoring data and simulating data. A prediction and evaluation system were set up. A typical mountainous city, i.e., Yunyang city in Chongqing in China, was taken as an example, its urbanization trend and population growth was predicted and evaluated. The heat island intensity and its trend were simulated, the temperature field, velocity field and the humidity field were analyzed. The results show that GIS is an effective tool to deal with the outdoor thermal environment, especially for the mountainous cities with special geographical particularities. GIS can be used in the environmental management and the city planning especially for the mountainous cities.

Optimization of environmental maintenance system used in a refuge chamber

Mine refuge chambers are used to shield miners who fail to escape from the mine when incidents occur. Environment maintaining system plays a key role in stabilizing thermal environment of a mine refuge chamber against heat emitted from metabolism and transferred from outside. The safety and comfort of refugees are closely related to the environment maintaining system design. In order to improve the comfort of refugees, optimization on the environment maintaining system has been done based on the previous work. To evaluate the environment of the chamber, eight volunteers were involved into the experiment. Under close observation and safety protection, they lived in a heat-isolated test chamber for 106 hours. The volunteers were asked to maintain low level of activities to simulate refugees＇ situation. It shows that the environment maintaining system worked well and the temperature, relative humidity and emitted harmful air content such as CO2 and CO were all kept in the safety level, and no discomfort was felt by volunteers at all.

Adaptive Thermal Comfort for Occupants of Low-Cost Dwellings in a Hot Dry Climate

Adaptive models are based on the observation that there are some actions that people can and actually do take to achieve thermal comfort. Studies regarding thermal comfort conditions in economical dwellings were carried out simultaneously in seven Mexican cities, corresponding to warm dry and warm humid climates. In this article, case studies of low-cost dwellings in the city of Hermosillo （in northwest Mexico）, are presented and analyzed. Field surveys were carried out to obtain information about the physical characteristics of the dwellings and their occupants, as well as the indoor thermal environment. Neutral temperature was obtained from the applied survey. The high neutral temperature reveals the effect of inhabitants＇ adaptation mechanism to extreme climates. Occupant comfort votes as a function of indoor air temperatures were analyzed, and different characteristics such as age, size and gender were evaluated separately. The results show the variability of the neutral temperature and the tolerance to temperature changes, depending on the population＇s specific characteristics. In many cases where the population does not have access to artificial acclimatization devices, the neutral temperature values for specific climates and people can inform architects when choosing the most suitable thermal strategies for building design.

Openwork Walls and Their Solar Applicability Range Jorge Hernan Salazar Trujillo

The environmental potential of perforated surfaces in the tropics is noticeable. They allow obtaining higher attenuation and spatial dispersion of both direct and diffuse lighting in indoor spaces, whereas in outdoor areas, the openwork elements reduce surfaces temperature and mitigate the characteristic glare of smooth surfaces when exposed to sunlight. Openwork walls have an immense sustainability potential in modern tropical buildings： they limit the solar rays＇ admission, as well as provide an advantageous use of natural light and cross ventilation, but the research on their solar behavior is scarce. In order to obtain suitable levels of solar gain, relationships among shape, proportion, thickness and partitions composing openwork elements must be studied. This research evaluates solar gain in perforated surfaces by defining the ＂solar applicability range＂, a property useful to identify intervals of guidance where a perforated pattern shape will present a definite solar gain, giving valuable input in the geometric design of openwork elements and introducing shade performance in the design of openwork walls. Results give geometric guidelines that allow to widen the solar applicability range of a perforation pattern and to define two perforation features that have impact on the solar performance of perforated surfaces： focalization and solar performance shift.

Faults and Claims about Thermal Environments in Relation to Energy Saving Measures in Smaller Office Buildings

Building equipment, energy-saving systems, and claims of inappropriate indoor thermal environments were analyzed in relation to the floor area using responses to a questionnaire survey of service managers of 157 buildings built in Osaka, Kyoto and Hyogo prefectures in Kinki area of Japan. Results show the following： （1） In smaller buildings （〈 5,000 m2）, setting temperatures are higher in summer and lower in winter, effects of ＂uncomfortable radiation from windows＂ are greater, energy-saving systems decrease indoor thermal comfort, but claims of ＂hot＂ and ＂cold＂ are fewer; （2） Claims of ＂hot＂ and ＂cold＂ are unrelated to the setting temperature and whether the air-conditioning control system is central or local; （3） The adoption rates of mitigation of dress codes （＂COOL-BIZ＂ and ＂WARM-BIZ＂） are higher than those of temperature mitigation of air conditioning.

Prediction model of the radiation from ground surface to the occupant in outdoor space

The outdoor ground radiation including the emitted radiation and reflected radiation plays an important role in the outdoor thermal environment. In this paper, based on the hypothesis of that the occupant body can be equivalent to a human cylinder and the outdoor ground surface is diffusive for radiation, a mathematical model is advanced to describe the radiation from the ground surface to the occupant. Through theoretical analysis of the mathematical model, general formulas for calculating the radiation arriving at the occupant from an annular ground surface and infinite ground surface are obtained. It shows that, the radiation from ground surface to the occupant depends on the surface temperature, reflectivity and emissivity, the arrange within the radius of 8.0m encircling the occupant can be defined as the dominant radiating area which radiates 90% radiation to the occupant. The radiative potentials of different pavement surface such grass, asphalt concrete surface, granite slab surface, terracotta bricks, colored concrete interlocking blocks are also compared with the datum measured by Tan Slew-Ann and Fwa Tien-Fang in Singapore, it shows that, in the summer sunny day, grass surface radiates more radiation in the morning but less in the afternoon than other pavement materials. Finally, discussions of reducing the radiation of outdoor ground surface are presented and main conclusions are drawn for improving the outdoor thermal environment.

Research on the Design and Energy Saving of New Rural Residential in the Southwest Area

The paper use advantage of local natural resources, greening and sufficient water resources, combine natural ecological environment design with rural architecture, and fully consider local economic base and material technical conditions, and takes site selection and planning, architectural design technology as the two core aspects to study rural residential energy conservation, improving thermal environment of indoor residential that use of nature building energy saving technique, efforts to reduce the use of mechanical equipment system, thereby reducing the rural residential building energy consumption.

Getting Free Heat Energy Based on Cavitation and Nuclear Fusion according to Revinov＇s Pilot Plants

In this report, the author describes and compares two innovative processes for producing thermal energy based on cavitation and nuclear fusion reactions in the indoor environment. Experiments conducted in the laboratory IHS （Intensive Heating System） of IE ＂Revinov N. M.＂ indicate that the process of lasso-vortex cavitation, which generates by means of an electric arc obtained HV-EI, gas-liquid plasma state in the EHH-CTC （electro-hydraulic heater with cavitation thermal camera） is not inferior and sometimes even superior in heat transfer to NF-AC （nuclear fusion reactions in ambient conditions）.