Evaluation of thermal comfort in a rail terminal location in India

The recent Indian Railway budget proposes upgrading and development of fifty railway stations to world class standards. These stations act as crucial transport nodes for effective operation of the railway network and passenger well being. One of the important aspects regarding passenger satisfaction in these places is an acceptable thermal environment. This article studies the thermal comfort of passengers in a large and significant railway station in South India in the summer month of June. The study entails field measurements and questionnaire responses from 402 individuals over a period of fifteen days. The thermal comfort is estimated using the air temperature and the PET (Physiological Equivalent Temperature) scale. The neutral temperature obtained through questionnaire surveys is 31.93 °C. In presence of fair air movement, there is some relaxation to neutral temperature, although the range of relaxation is much narrower than the models presented by other researchers. Comparing the Thermal sensation votes (ASHRAE 7-point scale) with comfort votes (Bedford 7-point scale), it is observed that the passengers exhibit high tolerance and adaptivity. Further, some observations are made on the relationship between the nature of waiting areas and their spatial influence on passenger thermal comfort.     

Modeling dynamic responses of aircraft environmental control systems by coupling with cabin thermal environment simulations

Commercial aircraft use environmental control systems (ECSs) to control the thermal environment in cabins and thus ensure passengers’ safety, health, and comfort. This study investigated the interaction between ECS operation and cabin thermal environment. Simplified models were developed for the thermodynamic processes of the key ECS components in a commercial software program, ANSYS Simplorer. A computational fluid dynamics (CFD) program, ANSYS Fluent, was employed to simulate the thermal environment in a cabin. Through the coupling of Simplorer and Fluent, a PID control method was applied to the aircraft ECS in Simplorer to achieve dynamic control of the temperature of the supply air to the cabin, which was used as a Fluent input. The calculated supply air temperature agreed with the corresponding experimental data obtained from an MD-82 aircraft on the ground. The coupled model was then used to simulate a complete flight for the purpose of studying the interaction between ECS operation and the cabin thermal environment. The results show that the PID controller in the ECS can maintain the cabin air temperature within ±0.6 K of the set point, with an acceptable air temperature distribution. The coupled models can be used for the design and analysis of the ECS and cabin thermal environment for commercial airplanes.     

Local and overall thermal comfort in an aircraft cabin and their interrelations

In this study the interrelation between local and overall thermal comfort of passengers in aircraft cabins was investigated by thirteen simulated flights. For each of the tests forty test persons filled out questionnaires concerning their perceived overall and local thermal comfort at temperatures of 20 °C–25 °C, which were measured at every second seat. With these physical and subjective data PMV (Predicted Mean Vote) and TSMV (Thermal Sensation Mean Vote) of test persons as well as PPD (Predicted Percentage of Dissatisfied) and PD (Percentage of Dissatisfied) were compared. The PMV was consistently similar to the TSMV, while the thermal dissatisfaction in tests was always higher than PPD. The hypothesis at the beginning of this study was that the high ratio of thermal dissatisfaction in the aircraft cabin reported in literature might be caused by local discomfort. Therefore statistical analyses about the interrelations between local and overall thermal comfort were performed and models indicating such interrelations were developed. Some local perceptions are significantly different from overall thermal perception and these body segments alter in dependence of the overall thermal environment. Also body segments rated similarly were detected and these segments were pooled to distinct body regions using principal component analysis. Under the same overall thermal sensation the local thermal perception on a certain body region predominantly influenced the overall thermal comfort. Therefore weighting factors of local body regions on the overall thermal comfort were determined in dependence of the overall thermal sensation by means of multiple linear regression models.     

Combined comfort model of thermal comfort and air quality on buses in Hong Kong

Air-conditioning settings are important factors in controlling the comfort of passengers on buses. The local bus operators control in-bus air quality and thermal environment by conforming to the prescribed levels stated in published standards. As a result, the settings are merely adjusted to fulfill the standards, rather than to satisfy the passengers' thermal comfort and air quality. Such "standard-oriented" practices are not appropriate; the passengers' preferences and satisfaction should be emphasized instead. Thus a "comfort-oriented" philosophy should be implemented to achieve a comfortable in-bus commuting environment. In this study, the achievement of a comfortable in-bus environment was examined with emphasis on thermal comfort and air quality. Both the measurement of physical parameters and subjective questionnaire surveys were conducted to collect practical in-bus thermal and air parameters data, as well as subjective satisfaction and sensation votes from the passengers. By analyzing the correlation between the objective and subjective data, a combined comfort models were developed. The models helped in evaluating the percentage of dissatisfaction under various combinations of passengers' sensation votes towards thermal comfort and air quality. An effective approach integrated the combined comfort model, hardware and software systems and the bus air-conditioning system could effectively control the transient in-bus environment. By processing and analyzing the data from the continuous monitoring system with the combined comfort model, air-conditioning setting adjustment commands could be determined and delivered to the hardware. This system adjusted air-conditioning settings depending on real-time commands along the bus journey. Therefore, a comfortable in-bus air quality and thermal environment could be achieved and efficiently maintained along the bus journey despite dynamic outdoor influences. Moreover, this model can help optimize air-conditioning control by striking a beneficial balance between energy conservation and passengers' satisfaction level.     

Evaluating the commercial airliner cabin environment with different air distribution systems

Ventilation systems for commercial airliner cabins are important in reducing contaminant transport and maintaining thermal comfort. To evaluate the performance of a personalized displacement ventilation system, a conventional displacement ventilation system, and a mixing ventilation system, this study first used the Wells‐Riley equation integrated with CFD to obtain the SARS quanta value based on a specific SARS outbreak on a flight. This investigation then compared the three ventilation systems in a seven‐row section of a fully occupied, economy‐class cabin in Boeing 737 and Boeing 767 airplanes. The SARS quanta generation rate obtained for the index patient could be used in future studies. For all the assumed source locations, the passengers’ infection risk by air in the two planes was the highest with the mixing ventilation system, while the conventional displacement ventilation system produced the lowest risk. The personalized ventilation system performed the best in maintaining cabin thermal comfort and can also reduce the infection risk. This system is recommended for airplane cabins.     

Advantages for passengers and cabin crew of operating a gas-phase adsorption air purifier in 11-h simulated flights

Experiments were carried out in a three-row, 21-seat section of a simulated aircraft cabin installed in a climate chamber to evaluate the extent to which passengers' perception of cabin air quality is affected by the operation of a gas-phase adsorption (GPA) purification unit. A total of 68 subjects, divided into four groups of 17 subjects took part in simulated 11-h flights. Each group experienced four conditions in balanced order, defined by two outside air supply rates (2.4 and 3.3 l/s per person), with and without the GPA purification unit installed in the recirculated air system, a total of 2992 subject-hours of exposure. During each flight the subjects completed questionnaires five times to provide subjective assessments of air quality, cabin environment, intensity of symptoms, and thermal comfort. Additionally, the subjects' visual acuity, finger temperature, skin dryness, and nasal peak flow were measured three times during each flight. Analysis of the subjective assessments showed that operating a GPA unit in the recirculated air provided consistent advantages with no apparent disadvantages. PRACTICAL IMPLICATIONS: Operating a gas-phase adsorption (GPA) air purifier unit in the recirculated air in a simulated airplane cabin provided a clear and consistent advantage for passengers and crew that became increasingly apparent at longer flight times. This finding indicates that the expense of undertaking duly blinded field trials on revenue flights would be justified.     

Thermal perception,adaptation and attendance in a public square in hot and humid regions

Highly relevant to an individual's thermal perception, the thermal environment in outdoor public spaces impacts the use of such spaces. Thermal adaptation, which involves physiological, psychological and behavioral factors, also plays an important role in assessment of thermal environments by users. Given that these issues have rarely been addressed for outdoor environments in hot and humid regions, this study examines user thermal comfort in a public square in Taiwan. Physical measurements were taken and a questionnaire survey was used to assess the thermal comfort of subjects. The number of people visiting the square was also counted. Analytical results indicate that the thermal comfort range and neutral temperature of subjects was higher than those of people in a temperate region. Additionally, local subjects preferred a cool temperature and weak sunlight, and adapted to thermal environments by seeking shelter outdoors. Analytical results confirm the existence of thermal adaptation and illustrate the characteristics of, and variances in, thermal adaptation. During the cool season, the number of people visiting the square increased as the thermal index value increased. However, the number of people frequenting the square decreased as the thermal index increased during the hot season. These experimental results were compared with those for temperate regions, indicating that the human energy balance model cannot fully explain the influence of climate on use of public spaces; that is, psychological and behavioral factors also play important roles in outdoor thermal comfort. Study findings also elucidate design of outdoor public spaces in hot and humid regions.     

Thermal comfort in care homes: vulnerability,responsibility and ‘thermal care’

Care homes are a distinctive setting for the management of thermal comfort due to the expectations involving the provision of both a home environment and caring service. Based on six UK case studies, the care home setting is investigated for how owners, managers and staff understand thermal needs and how their management of thermal comfort is shaped. The core function of good quality care is understood as closely related to the provision of thermal comfort. The association between ‘old and cold' and the obligations that follow for the provision of care are deeply entrenched in activities: such as the provision of hot drinks, use of blankets and the non-stop operation of heating systems. The responsibility for the provision of ‘thermal care' for residents is challenging and complicated by the diversity of people living (and working) together, their occupation of communal spaces, and the interactions between the means of providing thermal comfort and physical safety. The wider implications are identified for the uptake of sustainable technology, patterns of thermal-related vulnerability and, most significantly, for how the ethics, agency and relationality of thermal care provision are to be understood. Future research needs and directions are considered.     

农村住宅夜间3种床/炕加热方式对比实验研究

提出一种新型热盘管炕作为夜间采暖方式,与村镇普遍使用的火炕、电热毯在被褥热环境和室内环境方面的差异进行对比实验。分析发现,电热毯采暖响应速度快,但被褥热均匀性差,供热能力有限,无法保障室内温度;火炕采暖响应速度较快,但被褥温度保障时间短、可调节性差,室内存在烟气,CO2浓度超标;热盘管炕采暖响应速度一般,但被褥温度分布均匀,温度稳定后人体热舒适区占比可达80%以上,且室内环境良好。     

The need for temperature zoning in high-performance residential buildings

The development from poorly insulated and leaky buildings to modern high-performance buildings, such as passive houses, has led to considerable improvements regarding thermal comfort. However, user evaluations of passive houses that solely employ air heating indicate that bathrooms are often perceived as too cold and bedrooms as too warm. Based on these experiences, the functional requirement of providing thermal comfort using only air heating has not been adopted in the Norwegian standard for passive houses. Instead, usually local heat sources are installed in living rooms and bathrooms to facilitate temperature zoning within the dwelling. The questions asked in this study are how well this heating and ventilation concept functions in practice from the occupants’ point of view and whether it provides thermal comfort in the various rooms. Therefore, a questionnaire was distributed to the occupants of a typical multifamily passive house project in Norway. Despite the small sample size, the findings give important insight into the residents’ perception of the thermal conditions and clearly demonstrate the limitations of the heating and ventilation solution. Based on the results, the need for further development and further studies to provide temperature zoning is outlined.     

哈尔滨高校教室热舒适现场研究

为了研究高校教室在学生上课期间的热环境和人体热舒适,在哈尔滨高校教室进行了现场研究。在测量室内热舒适参数的同时,学生填写对室内环境的热感觉和热舒适主观调查表,共调查了1285人次,得到了1285份人体热反应的样本。现场测试结果表明,哈尔滨高校自然通风教室全年人体热中性温度为23.4℃(t0)。     

载人航天器舱内通风空调特性和数值模拟

由于载人航天器这一密闭狭小空间及其微重力这一特殊环境,舱内通风空调问题和热舒适环境与地面的HVAC问题不同,微重力效应特别是自然对流大为减弱影响着通风换热效果。本文首先分析了舱内通风空调问题的特殊性,通过无量纲分析和计算微重力的流体力学效应,然后利用FLUENT软件对两种集中通风方式进行数值模拟。模拟结果表明：微重力下几乎不存在“冷风下坠”或者“热羽”现象;集中斜进风在一定的进风角度和Re数下出现分岔解现象;与常重力相同通风条件下,微重力下自然对流的减弱使得舱内温度降低,换热减少,因此满足常重力热舒适要求的通风条件不一定满足微重力下热舒适性的要求。     

基于变风量的相对热指标运行模式在地铁空调中的应用研究

地铁空调系统的控制站厅和站台在设计温度值不变的设计运行模式下不能满足乘客舒适性要求,乘客的舒适感随新风状态变化而变化。由于乘客在站厅和站台的停留时间短,应根据相对热指标来评价非稳定条件下乘客的舒适性要求。本文在变风量调节的基础上,建立了按相对热指标来调节运行地铁中央空调系统的理论模型,在满足人体舒适性要求的前提下,解决了站台和站厅温湿度耦合问题。本文以广州地铁二号线新港东站为例,对比分析了空调系统相对热指标运行模式和设计运行模式下的舒适性和能耗等特点,为运行模式的完善提供了参考。     

Spot Monitoring: Thermal comfort evaluation in 25 office buildings in winter

In Germany, the optimization of energy uses in buildings demands a strict compliance with the requirements for thermal comfort as proposed by the Norm DIN EN ISO 7730:2006 (originated in ISO 7730), regardless of the diagnosis the building users may state. In the present field study, a survey on thermal comfort is made for winter periods, covering 345 measurements in 148 work spaces belonging to 25 office buildings. The survey method consists on sensed measurements and simultaneously gathered questionnaire data given by office users. For measurements, a mobile unit equipped with temperature, air humidity and airflow speed sensors was employed; the questionnaire inquired on thermal aspects of the close environment within the office. The main objective of the survey is to define an optimal operative temperature that can be attained by assessing the relationship between the measured data and the subjective data given by the users. The evaluation of the thermal comfort takes on the basis of the Norms’ criteria and on the average rating (vote) on thermal sensation chosen by the users, namely, the Comfort Vote or CV. As a relevant result, it can be stated that the users express acceptance to pre-established thermal conditions, even though the thermal prediction index as proposed by the Norm (PMV, Predicted Mean Vote) indicates that said thermal conditions are not good.     

Post-occupancy evaluation and field studies of thermal comfort

The similarities and differences are explored in both the aims and the methods between post-occupancy evaluations and field studies of thermal comfort in buildings. The interpretations of the field study results are explored, especially the ways the results differ from laboratory experiments. Particular attention is drawn to the dynamic nature of the interaction between buildings and their occupants. Answers to questions of the type used in post-occupancy evaluations are compared with results from field studies of thermal comfort, and the implications of these findings for the evaluation of buildings and the conduct of post-occupancy evaluation are explored. Field studies of thermal comfort have shown that the way in which occupants evaluate the indoor thermal environment is context-dependent and varies with time. In using occupants as part of the means of measuring buildings, post-occupancy evaluations should be understood as reflecting the changing nature of the relationship between people, the climate and buildings. Surveys are therefore measuring a moving target, and close comparisons based on such surveys need to take this in to account.     

Passenger evaluation of the optimum balance between fresh air supply and humidity from 7-h exposures in a simulated aircraft cabin

A 21-seat section of an aircraft cabin with realistic pollution sources was built inside a climate chamber capable of providing fresh outside air at very low humidity. Maintaining a constant 200 l/s rate of total air supply, i.e. recirculated and make-up air, to the cabin, experiments simulating 7-h transatlantic flights were carried out at four rates of fresh outside air supply--1.4, 3.3, 4.7, and 9.4 l/s per person (3, 7, 10, and 20 cfm/person)--resulting in humidity levels, ranging from 7% to 28% relative humidity (RH). Four groups of 16-18 subjects acted as passengers and crew and were each exposed to the four simulated flight conditions. During each flight the subjects completed questionnaires three times to provide subjective ratings of air quality and of symptoms commonly experienced during flight. Physiological tests of eye, nose, and skin function were administered twice. Analysis of the subjective assessments showed that increasing RH in the aircraft cabin to 28% RH by reducing outside flow to 1.4 l/s per person did not reduce the intensity of the symptoms that are typical of the aircraft cabin environment. On the contrary, it intensified complaints of headache, dizziness, and claustrophobia, due to the increased level of contaminants. PRACTICAL IMPLICATIONS: The investigation shows that increasing aircraft cabin humidity by decreasing the ventilation flow rate of fresh outside air would not decrease reports of discomfort made by cabin occupants.     

拉萨传统藏式建筑主观热舒适评

该文通过问卷访谈的方式对拉萨市传统藏式建筑居民的主观热舒适评价进行了调研,包括热湿感觉,室内风速的主要因素进行了分析,并提出主观热舒适具有差异性和动态性两种属性,为具有独特气候和地域特征等环境要素以及总体热舒适评价等。调查数据表明,虽然拉萨传市传统藏式建筑室内热环境不能达到ASHARE标准,但是居民总体热舒适满意程度较高,说明当地居民的热适应起到主导作用,该文对影响受访者的热适应地区的热舒适研究提供一个新的视角。     

对热舒适、空气感觉质量及能耗的模拟研究

室内空调设计温度和新风量对热舒适，室内空气质量及能耗量有重要影响，然而对它们之间相互关系进行研究的文献却较少。通过计算机模拟空调系统在7种室内设计温度和7种新风量条件下的运行情况，得到不同的设计条件组合对热舒适、人体感觉空气质量及建筑能耗量的影响。基于这项分析，提出了此办公建筑合理的室内设计温度和新风量取值。     

寒冷地区中小型高铁站候车厅夏季热舒适性及节能潜力研究

选取寒冷地区中小型高铁站,采用问卷调查与物理测试结合的方法,研究寒冷地区高铁站候车厅中旅客的热舒适度,得出旅客的中性温度与舒适温度阈值,并进而代入能耗模拟,探究热舒适与建筑能耗耦合作用下的高铁站房夏季节能潜力。研究结果表明,对于夏季高铁站候车厅,旅客中性温度为25.92℃,热舒适区间为22.03~28.43℃。通过中性温度及热舒适区间设置优化,其能降低约5%~11%的制冷能耗;而舒适区间范围内的能耗波动幅度为92 107 k W·h,约占制冷能耗的24.32%,节能效果可观。     

冬季室内热环境与被褥微气候的匹配

冬季睡眠状态下,室内热环境与被褥微气候分别对人体头部和被覆躯体的热感觉造成直接影响。为了分析两个热环境的匹配关系以满足睡眠人体的热舒适水平,实验在不同的室内温度下,调节被褥微气候温度,测试了受试者的皮肤温度,并记录了热感觉和热可接受水平。研究结果表明:睡眠状态下,相比于室内热环境,人体热感觉对被褥微气候更敏感;此外,通过分析室内热环境和被褥微气候分别与整体热感觉和整体不满意率的关系,得到了睡眠热环境舒适区间。