An analysis on spatial variation of urban human thermal comfort in Hangzhou, China

Urban human thermal comfort(UHTC) is affected for interacting of weather condition and underlying surface framework of urban area. Urban underlying surface temperature value and Normalized Difference Vegetation Index(NDVI) were calculated using image interpreting and supervised classification technique by ERDAS IMAGE software using 1991 and 1999 Landsat TM images data. Reference to the relational standard of assessing human thermal comfort and other meteorology data of Hangzhou City in summer, air temperature and relative humidity variation of different land types of underlying surface were inversed. By choosing discomfort index as an indictor, the spatial distribution characteristic and the spatial variation degree of UHTC were estimated and mapped on a middle scale, that is, in six districts of Hangzhou. The main characteristics of UHTC spatial variation from 1991 to 1999 were revealed using a GIS-based calculation model. The variation mechanism were analyzed and discussed from the viewpoint of city planning, construction and environmental protection.

The effect of Urban Heat Island mitigation strategies on outdoor human thermal comfort in the city of Baghdad

Todays,most Iraqi cities suffer from extremely hot-dry climate for long periods throughout the year.However,most urban patterns that exist inside these cities are not suitable for this harsh conditions and lead to an increase in the value of the Urban Heat Island(UHI)index.Consequently,this will increase outdoor human thermal discomfort as well as energy consumption and air pollution in cities.This study attempts to evaluate the effect of UHI mitigation strategies on outdoor human thermal comfort in three different common types of urban patterns in the biggest and most populated city in Iraq,Baghdad.Three different mitigation strategies are used here-vegetation,cool materials,and urban geometry-to build 18 different scenarios.Three-dimensional numerical software ENVI-met 4.2 is utilised to analyse and assess the studied parameters.The input data for simulations process are based on two meteorological stations in Baghdad:Iraqi Meteorological Organization&Seismology,and Iraqi Agrometeorological Network.All measurements are taken in a pedestrian walkway.The results of different scenarios are compared based on their effect on human thermal comfort.Outdoor thermal comfort is assessed according to Predicted Mean Vote index,as mentioned in ISO 7730 standard.This study provides a better understanding of the role of UHI mitigation strategies on human thermal comfort in the outdoor spaces of Baghdad’s residential neighbourhoods.This can help generate guidelines of urban design and planning practices for better thermal performance in hot and dry cities.

Impacts of Roof/Ground Mitigation Strategies on Improving the Urban Thermal Environment and Human Comfort over the Yangtze River Delta, China

The combined effects of global warming and the urban heat islands exacerbate the risk of urban heat stress. It is crucial to implement effective cooling measures in urban areas to improve the comfort of the thermal environment. In this study, the Weather Research and Forecasting Model(WRF), coupled with a single-layer Urban Canopy Model(UCM), was used to study the impact of heat mitigation strategies. In addition, a 5-km resolution land-cover dataset for China(ChinaLC), which is based on satellite remote sensing data, was adjusted and used, and 18 groups of numerical experiments were designed, to increase the albedo and vegetation fraction of roof/ground parameters. The experiments were conducted for four heatwave events that occurred in the summer of 2013 in the Yangtze River Delta urban agglomeration of China. The simulated results demonstrated that, for the single roof/ground schemes, the mitigation effects were directly proportional to the albedo and greening. Among all the experimental schemes, the superposed schemes presented better cooling effects. For the ground greening scheme, with similar net radiation flux and latent heat flux, its storage heat was lower than that of the roof greening scheme, resulting in more energy flux into the atmosphere, and its daytime cooling effect was not as good as that of the roof greening scheme. In terms of human thermal comfort(HTC), the improvement achieved by the ground greening scheme was better than any other single roof/ground schemes, because the increase in the relative humidity was small. The comprehensive evaluation of the mitigation effects of different schemes on the thermal environment presented in this paper provides a theoretical basis for improving the urban environment through rational urban planning and construction.

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.

Thermal Sense Prediction Model for Definite Human Group in Indoor Case

In order to build a prediction model of the indoor thermal comfort for a given human group, the original predicted mean vote （PMV） equation is reconstructed and simplified, the modified PMV equation is named PMVR （PMV for region） , where five variables are needed to be fitted with the dataset of actual thermal sense of a definite human group. As the fitting algorithm, the particle swarm optimization algorithm is used to optimize the solution, and a fixed PMVR can be finally determined. Experiment results indicate that for a definite human group, PMVR is more accurate on the prediction of thermal sense compared with some other models.

上躯干皮肤温度冷热变化与热量调节区划分

针对制冷与加热一体式服装中冷热调节区域设计问题,以皮肤温度为依据,探究人体受冷热环境影响上躯干各部位的冷热需求程度。分别测量冷与热2种环境下,青年男子在静坐、站立、步行、快走4种运动状态中上躯干不同区域的皮肤温度,分析各部位皮肤温度变化来判断人体局部区域的冷热情况,对皮肤温度变化值采用聚类分析来进行冷热调节区域的划分。结果表明:在冷环境下,人体上躯干皮肤温度在任一状态下侧胸、后肩温度均较低,且在静坐、站立阶段中明显低于人体平均皮肤温度;热环境下,任一状态下前肩、后肩温度均较高,前肩、后肩、中背明显高于人体平均皮肤温度,故侧胸、前肩及后肩等部位的冷热需求是功能服装设计的重点。

被服系统热舒适性测评方法研究进展

为了对睡眠人体热舒适进行准确评估,提高睡眠质量,文章研究了被服系统热舒适性的测评方法。首先总结和分析了被服系统的热阻测量方法,包括热平板法、暖体假人测试法和数值模型预测法。其次,探讨了基于人体热反应的热舒适性测评方法,包括主观热评价、热生理评价和睡眠姿势监测评价,阐述了目前用于被服系统热舒适预测的数学模型。最后,剖析当前研究的不足,提出未来被服系统热舒适性测评方法的研究应从被服系统热阻的测定、非接触式的睡眠热舒适评价、机器学习算法的应用3个方面展开。

针对有热源情况下大空间厂房内两种送风方式的对比研究

通过数值模拟的方法对比研究机械通风(mechanical ventilation,MV)与自然通风(natural ventilation,NV)有室内发热源的情况下,室内热环境的动态变化特征。结果表明,在有热源情况下,室内房间会在高度方向形成明显的热力分层现象,从而导致工作台位置温度较高,降低人体热舒适性。MV和NV房间内,靠近进风百叶位置处的热环境明显优于室内其他位置的热环境。另外,无论是机械通风还是自然通风,在室内局部位置均存在气流死角,导致局部环境恶化,温度过高,不利于设备散热。

An Approach to Human Adaptability towards its Built Environment: A Review

This paper deals with the human adaptability to its built environment. The built environment as we know it rarely finds itself adapting to its surrounding context, whether it be on the level of interaction with humans or the climate. Humans and nature both are in a constant state of flux;moving, changing, sensing, and reacting to their context and information they gather and perceive. A barrier is formed between the built environment and humans and nature due to the fact that their inherent characteristics are utterly contrasting. It is commonly estimated that persons in urban areas spend at least 80% of their time indoors. This suggests that the quality of the indoor environment can have a significant impact on comfort, health, and overall sense of well being. The indoor environment of buildings should thus be designed and controlled, as to provide a comfortable and healthy space for occupants. In order to maintain the quality of the indoor environment, we mechanically condition our buildings to achieve constant, uniform and comfortable environments. The maintenance of thermal equilibrium between the human body and its environment is one of the primary requirements. History of thermal comfort and climate design shows a definite relation between them and research is needed to know “What are comfort conditions?” and “How buildings could adapt themselves to these conditions”.

气候适应性视角下传统村落空间格局分析——以南京市江宁区黄龙岘村为例

在乡村振兴背景下,对传统村落进行微气候和舒适度研究有利于保护传统村落的空间肌理和建设生态宜居的美丽乡村。以南京市江宁区黄龙岘村为对象,基于实地测量,针对庭院空间、街巷空间、滨水空间、休闲空间的微气候因子和可视因子开展定量研究,运用RayMan计算生理等效温度(PET),以PET量化各空间的客观热舒适度,结合问卷调查,分析人的主观热感受,通过主客观结合的方式研究微气候因子与人体热舒适度的相关性。结果表明,PET与空气温度呈显著正相关,与相对湿度呈显著负相关,相关性次于空气温度,与瞬时风速的相关性较弱。在此基础上,综合传统村落的空间格局,比较4种空间类型的气候条件,量化不同空间类型的热舒适性,并提出改造策略,以期为不同地区传统村落的空间设计提供新思路。

基于近似动态规划的建筑能量管理系统日内优化调度方法

为了维持建筑内部温度和应对随机量的波动,提出了一种建筑能量管理系统的日内优化调度方法。首先考虑建筑围护结构热平衡关系,得出与室温相关的人体舒适度函数,并以经济性最优为目标建立了建筑能量管理系统日内调度优化模型。然后提出近似动态规划(ADP)与模型预测控制(MPC)相结合的求解方法,采用历史数据作为训练集以应对新能源出力和温度、辐照等大量不确定性因素,将离线训练得到的分段线性函数作为日内调度的未来值函数。最后,算例分析表明所提出的MPC-ADP算法可以通过不断迭代得到近似最优的日内调度方案,并大幅提升人体舒适度。

基于PPG信号的人体热舒适性研究

环境温度的过高或者过低会对工作学习效率产生一定的负面影响,甚至可能损害人体健康。当前绝大多数环境温度调控策略都努力维持某一普适的温度,并不能满足人们真正的热舒适需求。通过光电容积脉搏波信号预测出人体热舒适状态进而制定温度调控策略,能够实时为人们提供最佳的热舒适环境。实验通过采集在不同环境温度条件下人体手指末端的光电容积信号,使用经验模态分解消除呼吸运动干扰,利用Inception&GRU (Gated Recurrent Unit)并行复合模型对脉搏波信号建模。实验结果表明,通过脉搏波信号构建的人体热舒适性模型在训练集上和验证集上分别取得99.92%和97.18%的准确率,达到完美分类。

基于CiteSpace的人体热调节模型研究分析

人体热调节模型在“人体-服装-环境”系统的热湿传递机理研究中具有非常重要的作用,一直是传热传质学、生理学、工效学、纺织服装、建筑与环境等多学科交叉研究的重点。利用CiteSpace软件,从文献计量学的角度对Web of Science核心合辑收录的499篇有关人体热调节模型的研究论文进行数据可视化处理和分析。研究结果表明:东华大学、中国香港理工大学、清华大学是本领域的高产机构;Fiala模型、JOS模型和Gagge模型是近年来引用最多的热调节模型;我国热调节模型相关研究文献发表数位居世界第二,但因起步较晚,应用型研究较多,原创性热调节模型少,国际影响力较弱;计算流体力学和人工神经网络逐渐成为近几年的研究热点。

西安地区建筑空调供冷室内临界温度研究

发展超低能耗甚至近零能耗建筑已成为建筑行业实现“碳达峰、碳中和”的共识。以降低夏季空调能耗为切入点,针对无人工冷源情况下建筑室内设计温度上限的确定问题,以寒冷地区代表城市西安为例,以具有用户可调节空调的建筑为研究对象,在初夏时段采用客观物理环境测试和主观调查问卷收集相结合的方法,探究空调供冷室内临界温度,即室内温度达到多少度时使用者会开启空调。选取操作温度为室内热环境参数,在综合考虑前人热舒适现场调研成果的基础上,得到西安地区建筑空调供冷室内临界温度为28.16℃,对应实测不可接受率为15%;该温度阈值可作为节能建筑夏季室内热环境的控制目标,从而降低建筑空调能耗。

基于热舒适性的乘员舱气流组织设计

为研究乘员舱内不同气流组织下的人体热舒适性,找出进气参数对人体热舒适性影响的规律,将Fluent计算得到的9种进气方案的流场结果作为环境参数导入TAITherm中进行热舒适性分析。同时引入面部平均空气龄和能量利用率两项指标对乘员舱气流组织进行更全面的评价。结果表明进气总量对3位乘员热舒适性和平均面部空气龄影响程度最大,1号口进气温度对能量利用率的影响程度最大。综合考虑3位乘员的热舒适性、面部平均空气龄和能量利用率3项评价指标,发现当进气总量为1800 kg/h,1、2号口进气温度都为22℃,1、2号口进气量比值为6∶4时3项指标均表现良好,为最优的进气参数组合。

湿热地区夏季户外遮阳对人体生理温度与热舒适的影响

在全球气候变暖的背景下,湿热地区城市热环境面临着严峻的挑战,户外遮阳是改善城市热环境的有效措施,为探析夏季户外遮阳空间下人体生理量的变化与热舒适特点,选取无遮阳、植物与高架桥遮阳三类空间为研究对象,在夏季对其热环境参数与人体生理温度进行监测,并对人体热感觉和热舒适展开同步问卷调研。结果表明:从室内转向室外,人体生理温度变化主要分为两个阶段,第一阶段呈现不同程度的增大,无遮阳环境各生理温度增长速率均明显高于遮阳环境;第二阶段人体逐渐适应室外环境达相对稳态后,生理温度在一定范围内波动,期间无遮阳环境平均皮肤温度均值为34.42℃,分别高出植物与高架桥遮阳环境1.31℃与1.49℃;热舒适投票均值为1.24,分别高出植物与高架桥遮阳环境1.09和0.91个单位。此外,无遮阳环境下人体主观投票随停留时长变化明显,1 h内TSV与TCV均增大了约0.5个单位,而有遮阳环境的投票值则表现相对稳定。研究结果可为完善热适应模型、改良室外热舒适实验及理解城市微气候舒适感受机理提供数据支持与参考。

寒冷地区体育馆不同运动强度下的人体热舒适实验研究

运动人体的热感觉会受到地区、气候、运动状态、代谢率等多方面因素影响。按照代谢率将运动强度分为低、中、高三级,并对应具体运动类型。选取寒冷地区北京市某高校体育馆进行实验,过程中监测环境参数并记录受试者的生理参数、主观感觉。分析不同运动强度下的人体热感知特点与影响因素。结果表明:运动强度升高,运动人体的皮肤温度降低,心率和代谢率升高,热感觉更强烈,适应运动状态需要的时间更长。低强度运动下热感觉主要受环境温度和皮肤温度的影响。利用主成分分析法建立热感觉和热环境参数的回归模型,根据模型看出,低强度运动热感觉受环境参数影响较大,影响因子分别达到了0.557、0.840和0.419,中高强度运动热感觉受湿度影响较小,影响因子不超过0.1,建议实测场馆在运行不同运动强度的项目时进行分区域精细化调控。比较被试者实测热感觉与PMV值,发现代谢率越高的运动,二者偏差越大。比较男女性受试者的主观投票,发现男性受试者的热感觉和热舒适投票值的变化范围大于女性,男性更容易感觉到“热”。

北京奥林匹克森林公园绿地人体感热舒适度空间差异特征

【目的】城市公园绿地区域热环境存在空间分异特征,对绿地空间内部景观异质性与人体感舒适热度(简称体感舒适度)相关关系进行定量化研究,对改善城市环境舒适度具有重要意义。【方法】在北京奥林匹克森林公园绿地内选定典型植物群落结构、群落类型及景观环境样点区域,基于实测数据并使用兼顾主客观因素的PMV-PPD体感舒适度指标,阐明该公园绿地区域体感舒适度的空间分异特征。【结果】研究表明:从公园绿地不同植物群落结构区域的体感舒适度水平来看,乔-草型及乔-灌型双层结构区域较高,草坪/地被型及灌-草型结构区域次之,乔-灌-草型结构区域最低;从不同群落类型区域的体感舒适度水平来看,落叶阔叶型区域高于常绿针叶型、针阔叶混交型及草坪/地被型区域,灌丛型区域最低;从不同典型景观环境的体感舒适度水平来看,双层群落结构区域高于滨水及复层群落结构区域,单层及滨水广场群落结构区域的体感舒适度水平最低。【结论】为基于改善城市环境舒适度为目的的城市绿色空间规划设计及更新提供科学依据。

城市人体热舒适性评价的研究进展与展望

快速城镇化和气候变化导致显著的城市热岛效应,成为城市规划和设计必须考虑和缓解的重要生态环境问题。过去几十年,许多学者已经研究发明了许多热指数,用于户外热环境的模拟,进而评价人体对户外热感知情况。通过综述有关户外热环境的研究文献,归纳了目前户外热环境研究中常用的热指数及其常见计算平台,分析其使用范围和优缺点,总结未来发展方向。结果发现,当前人体热舒适性评价在指数原理、数据来源、计算技术方面存在限制;总结未来的研究趋势,包括户外热舒适性研究的新技术需求、多源数据的综合使用、长时间序列人体热指数时空分析、城市热舒适性与景观规划结合等。

基于营造及评价非均匀热环境目标的人体对流换热系数研究

为了精确评价非均匀热环境下人体热舒适性以营造低碳健康建筑环境,需要了解各方向气流下人体局部对流换热系数。本文基于实测实验及CFD模拟,对水平及竖直方向气流对人体局部对流换热系数的影响进行了研究,得到了人体各部位对流换热系数的计算模型,分析了各方向气流对人体对流换热系数的影响机制。结果显示:水平气流工况下的人体整体对流换热系数大于竖直气流工况;位于肢体末端的手部、小臂、脚部的对流换热系数较大;处于人体中心部位的腰腹部和背部的对流换热系数较小,且受不同方向气流影响较小。