Evaluating the performance of thermal sensation prediction with a biophysical model

Neutral thermal sensation is expected for a human body in heat balance in near‐steady‐state thermal environments. The physiological thermoneutral zone (TNZ) is defined as the range of operative temperatures where the body can maintain such heat balance by actively adjusting body tissue insulation, but without regulatory increases in metabolic rate or sweating. These basic principles led to the hypothesis that thermal sensation relates to the operative temperature distance from the thermoneutral centroid (dTNZ_op). This hypothesis was confirmed by data from respiratory climate chamber experiments. This paper explores the potential of such biophysical model for the prediction of thermal sensation under increased contextual variance. Data (798 votes, 47 participants) from a controlled office environment were used to analyze the predictive performance of the dTNZ_op model. The results showed a similar relationship between dTNZ_op and thermal sensation between the dataset used here and the previously used dataset. The predictive performance had the same magnitude as that of the PMV model; however, potential benefits of using a biophysical model are discussed. In conclusion, these findings confirm the potential of the biophysical model with regard to the understanding and prediction of human thermal sensation. Further work remains to make benefit of its full potential.     

现场研究中热舒适指标的选取问题

对热舒适现场研究结果进行了总结，并对热舒适指标的选取、有效温度的计算、热感觉的表述方式等问题进行了讨论分析。认为当相对湿度在热舒适范围内时，采用有效温度作为热舒适指标并采用平均热感觉值，能更好地预测人体热感觉。     

The distorted power of medical surgical masks for changing the human thermal psychology of indoor personnel in summer

The medical surgical mask (MSM) has been the essential protective equipment in people's daily work. The experimental purpose is to explore the effects of wearing MSM on human thermal sensation, thermal comfort, and breathing comfort in office buildings in summer. A total of 30 healthy college students were recruited for the testing. The experiment was carried out in a climate chamber, which can simulate the office buildings in summer. The experiment collects the subjects’ skin temperature, microclimate in the mask, and subjective votes, including thermal sensory votes (TSV), thermal comfort votes (TCV), and respiratory comfort votes (BCV). Experimental results show that wearing MSM has no significant effect on the skin temperature of the human body. The microclimate temperature inside the MSM reaches over 34℃, and the relative humidity reaches over 70%. The high-temperature and high-humidity microclimate put human beings in an uneven thermal environment, which leads to poor human tolerance to the thermal environment and becomes the main reason for destroying human thermal comfort. Wearing MSM has a significant impact on the subjective thermal sensation, thermal comfort, and breathing comfort of the human body, and the impact becomes more significant as the environmental temperature increases. Once the mask is taken off, the human body will enter an extremely comfortable environment, resulting in an excessively high vote value. The difference in voting values before and after removing the mask becomes larger with the environmental temperature. By fitting the voting results and perform data processing, it can be found that wearing MSM will reduce the neutral temperature by 1.5°C, and the environmental temperature with the optimal thermal comfort by 1.4°C, and as the temperature increases, the respiratory discomfort will become more and more intense. Regardless of whether wearing a MSM, the subjects preferred a slight warmer environment. In conclusion, with the increase of ambient temperature, wearing MSM can cause the human worse tolerance to the thermal environment, and this disturbance will become more and more intense.     

Shading effect on long-term outdoor thermal comfort

Shading affects outdoor thermal environments and, therefore, influences the thermal perceptions of people in outdoor spaces. Since most field studies examining outdoor thermal comfort merely elucidated characteristics measured on a particular day, these studies may not represent annual thermal conditions accurately. Therefore, this study conducted 12 field experiments to analyze outdoor thermal conditions on a university campus in central Taiwan, and utilized RayMan model for predicting long-term thermal comfort applying meteorological data for a 10-year period. The physiologically equivalent temperature (PET) is employed as a thermal index. The thermal comfort range of Taiwanese residents obtained in a previous survey was applied as the criterion for determining whether a thermal environment is comfortable or uncomfortable. Analytical results indicate that the sky view factor (SVF), which represents the percentage of free sky at specific locations, significantly affects outdoor thermal environments. Analytical results indicate that a high SVF (barely shaded) causes discomfort in summer and a low SVF (highly shaded) causes discomfort in winter. As Taiwan has hot summers and mild winters, sufficient shading should be provided by trees and buildings to improve thermal comfort in summer. However, since the Taiwanese have poor tolerance of cold temperature, outdoor space planning should avoid creating areas with excessive shading. Therefore, the thermal requirements of residents and characteristics of the local climate and environment must be considered when creating shaded outdoor areas.     

北京校园建筑夏冬两季室内热舒适性现场调查研究

测试了空气温度、平均辐射温度、相对湿度、风速等环境参数,采用问卷的形式调查了受试者的主观热感觉,建立了热感觉与室内操作温度的对应关系。在夏季,人们对偏热环境的耐受力强于PMV预测结果;在冬季,人体对于偏冷环境具有适应性,若室内温度偏高,人会感觉不适,实际热感觉高于PMV预测值;由于供暖条件的差异,长期生活在我国南方的人冬季对于偏冷环境的适应性要强于北方人。     

不同行为方式下人体热感觉与室内环境之关系

对影响人体热舒适度的室内物理参数及瞬态热的影响关系进行了详细分析，并对不同行为方式下人体主观因素进行了阐述，指出设计人员在设计时应考虑诸多因素，不同的行为方式采取不同的设计，以使人体达到热平衡的理想状态。     

热舒适评价指标及冬季室内计算温度探讨

以Fanger热舒适方程及PMWV，PPD评价指标为理论依据，模拟计算了严寒地区居室热环境，结果表明，满足人体热舒适的室内空气温度为21－24℃，明显高于现行暖通规范规定的冬季居室内计算温度16－20℃。认为应研究适于我国严寒地区居民的热舒适标准。     

Perceived control in indoor environments: a conceptual approach

Building automation systems provide the potential to optimize the energy consumption of buildings as well as to detect failures in the operation of buildings. The system comprising building form–HVAC–building automation–user is becoming more complex. Providing the occupants with control over the indoor environment is widely accepted for its positive effect on their satisfaction. This paper explores what the term ‘perceived control’ means conceptually and draws implications for its application to the design and management of buildings. Personality- and environmental-psychology emphasize the importance of personal control to humans. The adaptive model of thermal comfort, findings from post-occupancy evaluations and surveys in real buildings also indicate the importance of high levels of perceived control. These models and findings exist in parallel and have not yet been interconnected and translated into models for the built environment. A new conceptual approach to explain perceived control is proposed. Satisfaction with the indoor environment occurs not only when ‘comfort’ is provided but also immediately after a successful control action, even if homeostasis has not yet been achieved (pleasure). Giving control to occupants can result in higher levels of satisfaction.     

路基温度场长期模拟中的地表热边界条件研究

在路基温度场模拟中,地表热边界常基于"附面层原理"确定,即假设一定深度(附面层厚度)的土体温度函数等于大气日平均温度函数加上一个温度增量。目前,附面层厚度和温度增量一般通过实际观测值回归分析得到,尚未建立起相应的理论和参数确定方法,无法定量分析路面材质、路面结构、太阳辐射、路面辐射对附面层厚度和温度增量的影响。首先通过理论分析,建立了附面层厚度的确定方法;然后建立了一维路面路基结构温度场模拟模型,并通过路基温度场反演分析,验证了数值模型的正确性;进而通过数值分析,研究了太阳辐射、路面辐射、对流换热和路面结构等因素对附面层底部温度增量的影响,给出了温度增量的确定方法和相应的设计图表和计算公式。     

焦作夏季居住建筑人体热舒适现场研究

采用环境参数测量与问卷调查同步进行的方式,研究了混合供冷模式下人们的热舒适性。结果显示,该地区夏季实测热中性温度为27.7℃,预测热中性温度为25.4℃,由热感觉法和直接询问法得到的80%可接受温度范围的上限分别为28.8℃和29.2℃,由这两种方法得到的期望温度分别为27.4℃和24.0℃;在混合供冷模式下,由于存在由空调环境进入非空调环境的情况,所以对热环境的不满意率要高于自然通风状态,可接受温度上限比自然通风状态低。     

长沙地区公共建筑热湿现状与热舒适性研究

本文通过对长沙地区夏季和冬季办公楼、博物馆、火车站候车室、酒店、商场和医院等公共建筑室内环境热湿参数进行实测以及对人员热感觉进行问卷调查,分析了不同公共建筑内的热湿现状和人体热舒适性。对现场测试结果进行分析可知,夏季火车站室内平均空气温度高达29.8℃,而博物馆内只有22.7℃;冬季大部分公共建筑(除酒店外)室内平均空气温度低于18.0℃。问卷调查统计结果表明夏季博物馆内人们热感觉偏冷、火车站候车室内热感觉偏热;而冬季博物馆、火车站候车室和商场内人们热感觉均偏冷。此外,各公共建筑内夏季实测平均热感觉投票值TSV低于理论PMV,而冬季高于理论PMV。进一步的人体热舒适性分析得到夏季和冬季公共建筑内实测热中性温度分别为27.4℃和15.7℃,而根据PMV获得的理论热中性温度分别为26.6℃和19.8℃,实测值与理论值的差别说明在该地区公共建筑内,人们的耐热和耐冷能力都有所增强。夏季和冬季公共建筑内能被80%的人们所接受的热舒适温度范围分别为25.5～29.4℃和13.5～19.6℃。本文分析得到的热中性温度和热舒适温度范围可为夏热冬冷地区公共建筑暖通空调系统的节能设计提供一定的参考。     

A novel on-off TRV adjustment model and simulation of its thermal dynamic performance

Field test results show that about 15% to 40% of building heat loss in China is attributable to poor heating systems regulation. The current method for addressing this problem is to install thermostatic radiator valves (TRVs) to the ends of radiators, a method adapted from northern Europe. However, this method has resulted in poor performance from delayed controlling action due to thermal inertia as well as insufficient system control accuracy. This is further compounded by incorrect operation by system users and a lack of financial incentives to regulate the system if users are not billed for their heat consumption. We present a new method for simultaneously heat controlling and metering. The core challenge is to design a control strategy that will maintain the room’s temperature. Thus, we established dynamic heat transfer models for water flow, the radiator and the building so as to obtain the optimal heating strategy. We also simulated the indoor thermal dynamic performance of the heating system with different heating loads, supply water temperatures, and supply water flow rates using three methods: a continuously changing flow rate (Method 1), a step-change flow rate based on temperature deviation (Method 2) and an intelligent step-change flow rate (Method 3) which predicts the duty cycle of the valve in the proceeding period and controls the valve’s on-time. The simulation results indicate the performance of these three methods. For Method 1, as the room temperature is above the set point, the flow rate can be automatically reduced to a level which is proportional to the room temperature deviation. Further, the scale factor of the flow rate is designed according to the +2°C deviation, so it is accepted that the room temperature is higher than the set point by +2°C using this method. However, this low control precision is unsatisfactory. The mean temperature is higher than the set point and greatly affected by the heating load and supply water’s temperature and flow rate. For Method 2, the controlling action is delayed by thermal inertia, the room temperature fluctuates between the highest and lowest levels, and the temperature deviation can be greater than the set value. For Method 3, both the simulation and field test results showed that room temperature deviation was maintained within a ±0.5°C range under the various conditions. This method appears relatively robust and adaptable, and was the best control strategy of the three methods.     

A comparative analysis of urban and rural residential thermal comfort under natural ventilation environment

The paper presents a field study of occupants’ thermal comfort and residential thermal environment conducted in an urban and a rural area in Hunan province, which is located in central southern China. The study was performed during the cold winter 2006. Twenty-eight naturally ventilated urban residences and 30 also naturally ventilated rural residences were investigated. A comparative analysis was performed on results from urban and rural residences. The mean thermal sensation vote of rural residences is approximately 0.4 higher than that of urban residences at the same operative temperature. Thermal sensation votes calculated by Fanger’s PMV model did not agree with these obtained directly from the questionnaire data. The neutral operative temperature of urban and rural residences is 14.0 and 11.5 °C, respectively. Percentage of acceptable votes of rural occupants is higher than that of urban occupants at the same operative temperature. It suggests that rural occupants may have higher cold tolerance than urban occupants for their physiological acclimatization, or have relative lower thermal expectation than urban occupants because of few air-conditioners used in the rural area. The research will be instrumental to researchers to formulate thermal standards for naturally ventilated buildings in rural areas.     

Revisiting thermal comfort models in Iranian classrooms during the warm season

The validity of existing thermal comfort models is examined for upper primary school children in classroom settings. This is of importance to enhance productivity in the learning environment and to improve the control of artificial heating and cooling, including the potential for energy savings. To examine the thermal perceptions of children aged 10–12 years in non-air-conditioned classrooms, three sets of field experiments were conducted in boys’ and girls’ primary schools in Shiraz, Iran. These were undertaken during regular class sessions covering cool and warm conditions of the school year, polling responses from 1605 students. This paper illustrates the overall methods and reports the results of the warm season field survey (N?=?811). This investigation suggests that predicted mean vote-predicted percentage of dissatisfied (PMV/PPD) underestimates children's actual thermal sensation and percentage dissatisfied in the investigated classrooms. The analysis shows that sampled children may be slightly less sensitive to indoor temperature change than adults. The upper acceptable temperature derived from children's responses corresponding to mean thermal sensations of +0.85 is 26.5°C, which is about 1°C lower than the ASHRAE upper 80% acceptability limit. This implies that sampled children feel comfortable at lower temperatures than predicted by the ASHRAE Adaptive model during the warm season.     

Models of human thermoregulation and the prediction of local and overall thermal sensations

This study aims at comparing the predictions of skin temperature from different models of human thermoregulation and investigating the currently available methods for the prediction of the local and overall thermal sensations. In this paper, the Fiala model, the University of California, Berkeley (UCB) thermoregulation model and a multi-segmental (MS) Pierce model were tested against recently measured data from the literature. The local and overall thermal sensations were predicted for different room conditions, obtained from a recent experimental study, using the UCB comfort model coupled with the MS-Pierce model. The overall thermal sensation was further predicted using three other models. The predictions were then compared with the subjective votes obtained from that study. The equivalent temperature approach was also investigated based on the same experimental study. The results show comparisons of the predicted skin temperature by the thermoregulation models, under steady state and dynamic conditions, with the measured data as well as the predictions of the thermal sensations from the different models.     

A new thermal performance index for dwelling roofs in the warm humid tropics

This research aims to find a scientific rating scheme for roof system for the warm humid tropics. The overall air-to-air thermal transmittance (U-value) or thermal resistance (R-value) of roof are most widely used properties, but these are based on steady-state heat conduction and do not respond to changing conditions of climate, design and comfort needs. The paper presents a new thermal performance index, which is based on thermal comfort and actual thermal performance of a roof design option. It provides a basis for identifying the optimum roof design for unconditioned and acclimatised regimes. A review of the acceptable limits of ceiling surface temperature is presented. The mathematical modelling for predicting performance of roof based on admittance procedure and derivation of thermal performance index is described. In the proposed scheme the galvanized iron roof is given 0% rating and the roof satisfying the comfort needs for the given climate is rated as 100%. Illustrative examples of built roofs or design options are taken from India and Australia. It clearly shows that the roofs with the highest thermal resistance are not necessarily optimum solutions.     

严寒地区居住建筑室内热舒适模拟研究

将模拟计算得到的模型房间的温度场与经回归分析建立的平均热感觉MTS预测模型和热舒适评价指标PMV相结合,通过编制MATLAB程序,绘制了模型房间不同截面的MTS和PMV的三维分布图。比较了各个截面的MTS和PMV预测结果并分析了产生误差的原因。     

冰蓄冷低温送风系统设计方法(1):室内计算参数、舒适感、室内空气品质

介绍了国内外有关人体舒适感和室内空气品质的研究成果。认为低温送风空调系统可以改善室内环境、提高室内空气品质，给出了其室内计算参数并进行了详细说明。     

空调房间冬季室内致适参数的分析与研究

从人体热舒适感觉和室内空气品质方面分析了空调房间室内舒适性的影响因素,根据测试结果给出了致适范围,提出了工程应用中的注意的问题。     

Development of an adaptive window-opening algorithm to predict the thermal comfort,energy use and overheating in buildings

This investigation of the window-opening data from extensive field surveys in UK office buildings demonstrates: (1) how people control the indoor environment by opening windows; (2) the cooling potential of opening windows; and (3) the use of an ‘adaptive algorithm’ for predicting window-opening behaviour for thermal simulation in ESP-r. It was found that when the window was open the mean indoor and outdoor temperatures were higher than when closed, but it was shown that nonetheless there was a useful cooling effect from opening a window. The adaptive algorithm for window-opening behaviour was then used in thermal simulation studies for some typical office designs. The thermal simulation results were in general agreement with the findings of the field surveys. The adaptive algorithm is shown to provide insights not available using non adaptive simulation methods and can assist in achieving more comfortable, lower energy buildings while avoiding overheating.