Environmental and human factors influencing thermal comfort of office occupants in hot—humid and hot—arid climates

The effects of environmental and individual factors on thermal sensation in air-conditioned office environments were analysed for two large, fully compatible thermal comfort field studies in contrasting Australian climates. In the hot—humid location of Townsville, 836 office workers were surveyed; 935 workers participated in hot—arid Kalgoorlie-Boulder. Overall perceived work area temperature and measured indoor operative temperature correlated moderately with thermal sensation for Townsville (T) subjects but only perceived temperature correlated with Kalgoorlie-Boulder (KB) sensation. Multiple regression analyses confirmed that indoor climatic variables (including Predicted Mean Vote) contributed to actual thermal sensation vote (24% T; 15% KB), with operative temperature having more of an effect in T than in KB. Subsequent analyses of individual characteristics showed no linear contributions to thermal sensation. The remaining variances were significantly related to perceived work area temperature (7% additional explained variance in T; 12% in KB). Mann Whitney analyses (after correction for climatic variables) showed that T subjects with higher job satisfaction had thermal sensations closer to ‘neutral’. Males, healthier subjects, non-smokers, respondents with earlier survey times and underweight occupants had lower median thermal sensations in KB. Townsville occupants appeared more adapted to their outdoor climatic conditions than Kalgoorlie-Boulder respondents, perhaps due to limited home air-conditioning. Further research into non-thermal impacts on gender-related thermal acceptability is suggested.     

Grey prediction on indoor comfort temperature for HVAC systems

This paper describes determination of indoor comfort temperature for efficiently Heating, Ventilating, and Air-Conditioning (HVAC) system under dynamical environment. Making occupants’ satisfaction on thermal comfort is still challenging by how the temperature setpoint of the fresh made-up air in conventional HVAC systems can be adapted properly (normally fixed) when surroundings changes in time. Essentially, being unknown ahead of time, the outdoor temperature is systematically predicted by grey prediction model in this work. The Adaptive Comfort Theory (ACT) model captures relation of the indoor comfort temperature to the outdoor temperature based on the survey data on thermal comfort in real occupants’ living environment. With the grey prediction model and the ACT model, the predicted indoor comfort temperature can be implemented as the comfort temperature reference for HVAC control systems. The experiment results show the viability of the proposed methodology for efficient HVAC control system.     

Environmental and human factors influencing thermal comfort of office occupants in hot - humid and hot - arid climates

The effects of environmental and individual factors on thermal sensation in air-conditioned office environments were analysed for two large, fully compatible thermal comfort field studies in contrasting Australian climates. In the hot - humid location of Townsville, 836 office workers were surveyed; 935 workers participated in hot - arid Kalgoorlie-Boulder. Overall perceived work area temperature and measured indoor operative temperature correlated moderately with thermal sensation for Townsville (T) subjects but only perceived temperature correlated with Kalgoorlie-Boulder (KB) sensation. Multiple regression analyses confirmed that indoor climatic variables (including Predicted Mean Vote) contributed to actual thermal sensation vote (24% T; 15% KB), with operative temperature having more of an effect in T than in KB. Subsequent analyses of individual characteristics showed no linear contributions to thermal sensation. The remaining variances were significantly related to perceived work area temperature (7% additional explained variance in T; 12% in KB). Mann - Whitney analyses (after correction for climatic variables) showed that T subjects with higher job satisfaction had thermal sensations closer to 'neutral'. Males, healthier subjects, non-smokers, respondents with earlier survey times and underweight occupants had lower median thermal sensations in KB. Townsville occupants appeared more adapted to their outdoor climatic conditions than Kalgoorlie-Boulder respondents, perhaps due to limited home air-conditioning. Further research into non-thermal impacts on gender-related thermal acceptability is suggested.     

Radiant heat and thermal comfort in vehicles

Infrared-reflective (IRR) treatment of automotive glass has been shown to reduce air temperature in vehicle cabins, thereby increasing fuel economy and occupant comfort. Its effect on radiant heat, however, may augment these benefits. In this study, the hypothesis that radiant heat affects subjective comfort ratings in a vehicle was tested. IRR films were systematically applied to the driver-side window of an outdoor stationary vehicle. In Phase 1, cabin air temperature was controlled while participants rated their thermal comfort. In Phase 2, air temperature was adjusted according to participants' responses. Results in Phase 1 showed that the IRR treatment improved thermal comfort on the left forearm, which was exposed to direct solar irradiance, but not whole-body thermal comfort. In Phase 2, participants indicated that they were comfortable at a higher air temperature (mean of 2.5 degrees F [1.4 degrees C]) with the IRR treatment than in the untreated condition. The results indicate that reducing radiant heat via IRR treatment affects subjective assessments of thermal comfort and allows occupants to maintain the same level of comfort in a warmer vehicle cabin. Applications of this research include future implementations of IRR treatment on automotive glass that may lead to greater fuel economy savings and occupant comfort than have previously been estimated.     

Georeferenced four-dimensional virtual environments: principles and applications

This paper introduces and defines the concept of a four-dimensional virtual environment as “multidimensional/multimedia representations of phenomena in natural and built environments permitting the realistic monitoring, analysis and evaluation of the component phenomena”. It is argued that current geographic information systems cannot handle these representations and so new tools need to be built. This paper describes two applications of virtual environments: the first is an application which can link oblique or vertical aerial videography to map or surface models in real-time, while the second example is an application which links a user-browseable virtual world with a map. The paper concludes by suggesting that the approaches demonstrated here are indicative of what the next generation of geographic information handling might look like.     

Comfort seat design: Thermal sensitivity of human back and buttock

In recent years, comfort seat design has received widespread attention from researchers. One of the factors that could contribute to comfort is the thermal influence due to the interaction between the human and the seating surface, for which literature is limited.In this paper, a laboratory experimental setup was used to detect and analyse the temperature changes at interface between seated subjects and a sensorized automotive seat. Acquired temperatures were processed in order to identify a mathematical model for describing the temperature changes at the interface.The main target of the study was the identification of the most sensitive areas of the human body to temperature variation while seated and its effect on local and overall perceived thermal comfort.Statistical analysis showed that the effects of temperature were most perceived in the “Upper Body” (UB) and less in the “Lower Body” (LB). The shoulders, the sides of the back, the back and the buttocks were most sensitive to temperature changes at the interface. Differences have been highlighted also between male and female subjects.Relevance to industryThe identification of the most sensitive areas of the human body to temperature variation, while seated, and the identification of the logarithmic model for describing the temperature changes should allow seat designers to define targets and strategies in developing cooling and heating systems for car seats, taking into account, in a preventive evaluation, the most probable perceived thermal comfort.     

Avatars Versus Agents: A Meta-Analysis Quantifying the Effect of Agency on Social Influence

Existing research has investigated whether virtual representations perceived to be controlled by humans (i.e., avatars) or those perceived to be controlled by computer algorithms (i.e., agents) are more influential. A meta-analysis (N = 32) examined the model of social influence in virtual environments (Blascovich, 2002) and investigated whether agents and avatars in virtual environments elicit different levels of social influence. Results indicated that perceived avatars produced stronger responses than perceived agents. Level of immersion (desktop vs. fully immersive), dependent variable type (subjective vs. objective), task type (competitive vs. cooperative vs. neutral), and actual control of the representation (human vs. computer) were examined as moderators. An interaction effect revealed that studies conducted on a desktop that used objective measures showed a stronger effect for agency than those that were conducted on a desktop but used subjective measures. Competitive and cooperative tasks showed greater agency effects than neutral tasks. Studies in which both conditions were actually human controlled showed greater agency effects than studies in which both conditions were actually computer controlled. We discuss theoretical and design implications for human–computer interaction and computer-mediated communication.     

面向高铁站的热舒适度和能耗综合预测

针对高铁站这类半封闭建筑的热舒适度影响因素众多,影响机制复杂以及热舒适度与能耗存在背反等问题,提出了基于机器学习的高铁站热舒适度与能耗综合预测方法。首先采用传感器数据捕获及Energy Plus仿真两种方式对高铁站室内外状态、多联机及热交换机等控制单元及热能传导环境进行建模;其次提出影响高铁站热舒适度的八类因素——多联机开启台数、多联机设置温度、热交换机开启台数、客流密度、室外温度、室内温度、室内湿度和室内二氧化碳浓度,并设计424种模型运行工况以及3 714 240个实例;最后设计6种机器学习模型——深度神经网络、支持向量回归、决策树回归、线性回归、岭回归和贝叶斯岭回归,来对高铁站室内热舒适度和空调能耗进行有效预测。实验结果表明,6种机器学习模型中决策树回归预测模型能够在较短的时间内获得最优的预测性能,其平均均方误差低至0.002 2。所得研究成果可直接为下一阶段的温控策略提供主动预判的环境状态参数并实现实时决策。     

Saliency detection analysis of collective physiological responses of pedestrians to evaluate neighborhood built environments

Crowdsourcing pedestrians’ physiological responses (e.g., electrodermal activity (EDA), gait patterns, and blood volume pulse) offers a unique opportunity for assessing and maintaining built environments in a neighborhood. However, raw physiological signals acquired from naturalistic ambulatory settings cannot effectively capture prominent local patterns in the data stream, since diverse technical challenges (e.g., electrode contact noise and motion artifacts) and confounding factors (e.g., heightened physiology due to the movement) make it difficult to detect significant fine-grain signal fluctuations. Motivated by this issue, this paper proposes a method to identify physical disorders that cause pedestrians physical discomfort and/or emotional distress, by using saliency detection analysis on physiological responses. A bottom-up segmentation approach was used as an unsupervised way to divide each physiological signal into homogeneous segments. A physiological saliency cue (PSC) is proposed to calculate the distinctiveness of physiological responses over each segment in contrast to the remaining segments, and the collective PSC of a physical point of interest is computed across participants. The results, obtained from physiological signals collected from wearable devices, indicate that the suggested saliency detection analysis is effectual in capturing prominent local patterns. Our statistical analysis further indicates that the proposed PSC features can be indicative of physical disorders. The outcome of this research will provide a foundation towards using physiological signals to evaluate built environments, and towards promoting neighborhood walkability, increasing feelings of safety in the urban space, and augmenting residents’ well-being.     

Realization of reconfigurable virtual environments for virtual testing

1 Introduction The scalability of virtual environments (VEs) that allow users to change and modify their contents and context depending on application requirements has been a de facto feature of virtual reality technology. Engineering uses such as virtual testing and exper- imenting applications demand VEs to be highly or fully reconfigurable. In reality, however, satisfactory reconfiguration of a virtual environment is yet to be achieved, due to the high accuracy of spatial data in- put and…     

A guide to thermal comfort

This guide provides a simple design procedure for dealing with the requirements for a comfortable thermal environment. From the expected activity level and clothing insulation of the people concerned, a subjective temperature is calculated which will provide thermal comfort. This subjective temperature is a combination of physical parameters of the environment, ie, air and mean radiant temperatures, and air speed. A heating system must be designed to that the parameters combine to give the optimum subjective temperature. The guide also considers other possible sources of discomfort, and gives acceptable limits for them.     

基于深度森林的高铁站室内热舒适度等级预测

对于高铁站这类半封闭半开放空间的室内环境热舒适度等级难以准确预测的问题,提出基于深度森林（DF）的深度学习方法对热舒适度等级进行科学预测。首先基于现场调研和Energy Plus平台对高铁站室的热交换环境进行建模;其次提炼出客流密度、多联机开行台数和多联机设置温度等8个影响因素,并设计424种工况以获取海量数据;最后采用DF挖掘热舒适度与影响因素之间的关系,以对高铁站室内热舒适度等级进行预测。采用深度神经网络（DNN）和支持向量机（SVM）作为对比算法进行验证。实验结果表明,在3种模型中,DF在预测正确率和weighted-F₁上表现最佳,DF的预测正确率最高达到99.76%,最低为98.11%。因此,DF能够有效预测高铁站室内的热舒适度等级。     

Recovery in sensory-enriched break environments: integrating vision,sound and scent into simulated indoor and outdoor environments

To deal with stress and exhaustion at work, personal resources need to be replenished during breaks. The aim of this laboratory study (n?=?122 students) was to test the restorative potential of sensory-enriched break environments (SEBEs) in between-subjects with repeated measures design, focusing on the type of the environment (natural outdoor vs. built indoor environment) and sensory input (no sensory input vs. audiovisual input vs. audiovisual and olfactory input). Analyses showed that SEBEs simulating either a natural or a lounge environment were perceived as more pleasant and restorative (fascination/being away) than a standard break room, which in turn facilitated the recovery of personal resources (mood, fatigue, arousal). Moreover, adding a congruent scent to an audiovisual simulation indirectly facilitated the recovery of personal resources via greater scent pleasantness and higher fascination and being away. The current study shows the opportunities for sensory enrichment to foster restoration in break environments.     

Navigation in hypertext through virtual environments

Users of hypertext systems require some form of navigation aid or 'browser'. Typically these have been produced as schematic representations of the hypertext network. The advent of 'virtual reality' technology, and particularly less costly forms of this, offers new possibilities for hypertext navigation whereby information can be presented in the form of a virtual environment. Users can then move around the virtual world in much the same conceptual fashion as they move around the real world. Based upon an extensive review of hypertext navigation problems and the aiding systems proposed to deal with these, four different types of navigation aid have been built; these are schematic and spatial representations in two and three dimensions. Of particular interest is the 3D spatial representation, built as a virtual environment in Virtus Walkthrough; the proposition is that such a virtual world navigation aid will offer substantial usability advantages for hypertext databases.     

How do thermal conditions in intensive care units affect the health and well-being of intensivists?

This study presents situational risk scenarios to predict the potential implications of predicted and perceived thermal configurations on the health and well-being of health care professionals in intensive care units (ICUs). Nine ICUs were selected, and thermal variables were collected; simultaneously, 128 health care professionals were interviewed to assess their perceptions, satisfaction, and health conditions related to their workplace environment. In scenarios with thermal comfort (either predicted or perceived), the risk of exposure to physical and psychological symptoms was reduced. This effect also extends to predictions and perceptions tending toward slightly cooler temperatures. In situations with a predicted mean vote below −1.5 and above 0.5, symptom complaints increased, even when the health care professionals perceived their environment as thermally comfortable, with the most extreme cases generating an increase of up to 27% in the baseline probability. Adjusting the workplace environment to be thermally comfortable can reduce symptom complaints.     

Mediating the expression of emotion in educational collaborative virtual environments: an experimental study

The use of avatars with emotionally expressive faces is potentially highly beneficial to communication in collaborative virtual environments (CVEs), especially when used in a distance learning context. However, little is known about how, or indeed whether, emotions can effectively be transmitted through the medium of a CVE. Given this, an avatar head model with limited but human-like expressive abilities was built, designed to enrich CVE communication. Based on the facial action coding system (FACS), the head was designed to express, in a readily recognisable manner, the six universal emotions. An experiment was conducted to investigate the efficacy of the model. Results indicate that the approach of applying the FACS model to virtual face representations is not guaranteed to work for all expressions of a particular emotion category. However, given appropriate use of the model, emotions can effectively be visualised with a limited number of facial features. A set of exemplar facial expressions is presented.     

Too hot to carry on? Disinclination to persist at a task in a warm office environment

We investigated the effect of an elevated ambient temperature on performance in a persistence task. The task involved the coding of incorrect symbols and participants were free to decide how long to spend performing this task. Applying a between-subject design, we tested 125 students in an office-like environment in one of the three temperature conditions. The comfort condition (Predicted Mean Vote [PMV] = 0.01) featured an average air temperature of 24 °C. The elevated ambient temperature condition was 28 °C (PMV = 1.17). Condition three employed an airstream of approximately 0.8 m/s, intended to compensate for performance decrements at the elevated air temperature (28 °C, PMV = 0.13), according to Fanger’s thermal comfort equation. Participants in the warm condition were significantly less persistent compared with participants in the control and compensation conditions. As predicted by the thermal comfort equation, the airstream seemed to compensate for the higher temperature. Participants’ persistence in the compensation and comfort conditions did not differ.

Practitioner Summary: A laboratory experiment involving a simulated office environment and three ambient temperature conditions (24 °C, 28 °C and 28 °C plus airstream) showed that persistence at a task is significantly impaired at 28 °C. An airstream of 0.8 m/s at 28 °C compensated for the disinclination to persist with the task.     

High-level interpretation in virtual environments

As virtual environments applications become more complex, there is a need to interpret user interaction in terms of high-level concepts. In this paper, the relations between conceptual representations of actions and their physical simulation in virtual worlds is investigated. A model inspired fromnatural language processing (NLP) research in the linguistic interpretation of dynamic scenes has been developed. The experiments are based on real-time animation software, which has been enhanced with a symbolic information processing layer, originally developed for NLP-based animation. We report the implementation of a high-level interpretation module that is able to recognize complex actions fromlow-level physical events in the virtual world and discuss its performance as well as directions for further developments.     

The assessment of heat radiation

Approximately 900 climatic chamber experiments were performed with 16 male subjects to study the thermal strain at climates including increased heat radiation. Based on the reactions of heart rate, rectal temperature and sweat rate, a heat stress index was developed for the assessment of climates with effective heat radiation intensities up to 1400 W m⁻². The index considers different combinations of dry air temperature (5–55°C), globe temperature (25–76°C), mean radiant temperature (25–160°C), air velocity (0.5–2.0 m s⁻¹), clothing, physical work load and directions of radiation and air flow.

The index integrates combinations of the variables producing the same degree of thermal strain into a single value. This value indicates the temperature of the physiologically equivalent climate in which air and radiant temperature are equal. It can be determined from a simple formula or from correspondent graphs.

In comparison, the international recommended heat stress indices are less capable to evaluate heat radiation correctly. The incorporation of the new partial index into the used indices may improve substantially their physiological validity in the assessment of climates with radiant heat stress.

Relevance to industry

The goal of this paper is to provide an improved assessment of thermal stress in working environments in which heat radiation is an important heat stress factor.