Quantitative Analysis of the Outdoor Thermal Comfort in the Hot and Humid Summertime of Shenzhen, China

Outdoor thermal comfort has always been a major issue due to its irreplaceable role in maintaining good health and energy use. Thus,quantitative analysis of outdoor thermal comfort and discussions on influential factors seem very necessary to achieve the climate-conscious urban design. Therefore,an outdoor thermal comfort questionnaire survey and the simultaneous field measurement were conducted in six different places during the hot and humid summertime in Shenzhen. The results show that the overall weather conditions during the investigation can be expressed with high temperature and high humidity with strong solar radiation. The micro-meteorological parameters of six test sites vary greatly due to their different regional spatial layouts.Moderate range of air temperature( Ta) is between 28 to 30 ℃ while that of relative humidity( RH) mainly concentrates in 60%-70% with the thermal sensation votes. The main influential factors impacting outdoor thermal comfort are obtained and Tahas the greatest effect. The overall thermal comfortable ranges in Shenzhen are expressed by the range of 28. 14-32. 83 ℃ of PET and 24. 74-30. 45 ℃ of SET*. With the correlation analysis between the characteristic parameters of regional spatial layout and thermal climate and thermal comfort,it reveals that increasing the coverage ratio of water and green space( S) helps lower Taand increase RH. The global solar radiation( G) has a significant negative correlation with the height of buildings( H) and a positive correlation with sky view factor( SVF). Overall,reasonable configuration of the regional spatial layout contributes to providing a thermal comfortable environment.

Urban Microclimate and Outdoor Thermal Comfort of Public Spaces in Warm-Humid Cities: A Comparative Bibliometric Mapping of the Literature

Intensified human population encourages urbanization changing the morphology and metabolism of urban environments, thus altering the local climate and outdoor thermal comfort (OTC) in public spaces. OTC is an increasingly urgent area of research for tropical climates. This study explores the literature from the Scopus database on urban microclimate and OTC in public spaces and contrasts the studies in warm-humid cities through a bibliometric mapping of literature. The adapted methodology includes;Bibliometric Search, Scientometric Analysis, and Content analysis using VOSviewer software to identify the evolution paths, gaps, and the most recent movement of OTC assessments in urban public spaces. Results reveal five evolution paths related to all climatic regions;1) materials and cooling strategies, 2) simulation modeling and urban planning, 3) design parameters affecting thermal perception, 4) cooling effects of green infrastructure, and 5) thermal adaptation in urban design. Although urban morphology and vegetation have been received the highest attention respectively, only a few for blue infrastructure related to warm-humid cities. This review identified five research gaps;the impact of blue infrastructure on OTC, strategies to overcome the effect of reflective materials, vegetation configurations in street canyons with wind flow, OTC improvements in asymmetrical street canyons, and how local climate zone (LCZ) classification approach could be used for OTC assessments. Past empirical studies have revealed that urban vegetation, surface materials, and morphological parameters are of paramount importance. Yet, the urban blue infrastructure has not received adequate research. Recently, the attention of researchers has been drawn to strategies in improving OTC using micro-meteorological simulation modelling to examine the impact of urban design interventions. Finally, comprehensive content analysis, bibliographic coupling based on documents, co-occurrence of all-keywords, are suggested for future bibliometric reviews. Finally, further research on recommended areas would assist decision-makers in planning and design to enhance livability by improving microclimate and OTC in urban spaces.

An investigation of the influence of ground surface properties and shading on outdoor thermal comfort in a high-altitude residential area

Landscape elements in residential areas can effectively improve the outdoor thermal environment,with different outcomes depending on the climate conditions.This study explores how the ground surface and shading properties affect the outdoor thermal environment in a high-altitude plateau climate where few studies have been conducted.The measurements were conducted during summer and winter in a residential area in Lhasa,Tibet.Without natural shading such as trees,there is a positive correlation between Sky-view factor(SVF)and Physiological equivalent temperature(PET)during winter and a negative correlation during summer.When SVF exceeds 0.65 in summer,it may cause human discomfort.Compared to artificial shading such as a tensioned membrane,deciduous trees are superior at improving human comfort,as they can increase PET by 10.56℃ in winter and decrease it by 9.73℃ in summer.During summer,high-reflection water-permeable bricks can reduce the PET by 1.08℃,and lawns can reduce the mean rachation temperature(Tmrt)by 1.650C;however,the lawns may produce a microclimate with a high air temperature.The results from this paper can be used as a reference for landscape planning and design in residential areas in high-altitude cold-climate regions.

Impact of building regulations on the perceived outdoor thermal comfort in the mixed-use neighbourhood of Chennai

The population in urban areas is increasing rapidly around the world in most of the cities.In India,this growth has forced the local governments to review the planning norms regularly with the main focus of making an affordable urban living.This resulted in increasing the built density without evaluating the effect of such developments on human thermal com-fort.Outdoor microclimate is one of the significant factors that determine the quality of out-door spaces.This study investigates the potential impact of the built geometry guided by the newly published development control rules of Chennai,India on the various parameters that influence microclimate.The existing and future scenario has been modelled for three locations in a typical mixed-use neighborhood of Chennai.Further,air temperature and relative humid-ity were measured in three locations on a typical summer month of May 2018.The recorded data was used for validating the simulated model and calibrating the model settings.Mostof the studies on outdoor thermal comfort compare a base case scenario and project future scenarios.This paper is a more realistic comparison of outdoor thermal comfort between the actual resultant built environment guided by the new Tamil Nadu Combined Development and Building Rules,2019 for selected locations and the existing built geometry which is the outcome of revised development control rules of 2013.The study found a significant reduction of 18℃in mean radiant temperature(Tmrt)and a reduction of 12℃in Physiological Equiv-alent Temperature(PET)between the 2013 and the predicted built geometry as per 2019 build-ing rules.Further the duration of extreme heat stress in the Physiological Equivalent Temperature(PET)scale show a reduction of 3 h during the day time,The study will assist ur-ban planners and designers to include outdoor thermal comfort also as an important factor while developing building rules.

Research on Thermal Comfort of Outdoor Space in Summer Urban Park: Take Mianyang Urban Park as an Example

One of the factors for the evaluation of the space environment is the comfort of outdoor activities spaces in urban parks. The space composed of different landscape elements has different microclimate environment. In this paper, in order to evaluate the role of thermal comfort in influencing resident’s assessment of the outdoor space and activities of the park, a thermal comfort survey was conducted on the outdoor open space of Mianyang Urban Park in summer. In this article, meteorological surveys, questionnaire surveys and observation of park attendance are selected to collect data. The physiological equivalent temperature (PET) assessment was selected as the index to evaluate resident’s thermal comfort level, and the comprehensive evaluation and analysis of the spatial thermal environment of different outdoor landscape elements in the park. The overall comfort of current visitors is mainly influenced by their subjective heat perception voting (TSV). In this article, we focus on providing microclimate adjustment considerations for urban park landscape design, and may help people understand the outdoor thermal comfort of Mianyang in summer, increase the using time of outdoor activities, and promote the use of outdoor space.

Effects of Outdoor Thermal Environment upon the Human Responses

In a summer outdoor space, the influence of short-wave length solar radiation on the human body is strongly apparent, heat is retained in the body, and the risk of heat disorders such as heat stroke increases. To avoid this, it is essential to seek shade to avoid the influence of short-wave length solar radiation. In addition, natural ground surfaces such as green spaces and water surfaces are useful in reducing the air temperature. It is indispensable to consider climate mitigation effect of outdoor space. The purpose of this study is to clarify the influence of the thermal environment of an outdoor space on the human body in rural and suburban regions where paddy fields remain. Subject experiments were conducted to examine the relationship between the thermal environment evaluation index enhanced conduction-corrected modified effective temperature (ETFe) in an outdoor space and the physiological and psychological responses of the human body. Experiment sites were selected with consideration for the natural ground surface such as bare ground where the surface is gravel or soil;paved ground such as concrete, asphalt or blocks;green areas covered in plants;and water surfaces, as well as the sky factor due to buildings or trees etc. and the proportion of the solid angle of components of greenery and water etc. comprising the solid angle of the total celestial sphere. A ground surface feature with a high heat capacity may promote sensation of hot and deteriorate the thermal sensation. A landscape of thick vegetation with a high green factor may have a strong feeling of confinement, which can make it somewhat hot and somewhat uncomfortable thermal environment due to the sense of stagnation. Compared with the urban environment, it is conceivable that the difference in the perceptual environment, whereby it is subconsciously assumed to be a comfortable thermal environment, had an effect in the rural and suburban regional environment, resulting in an ETFe lower than the upper limit of comfort in a summer urban environment.

寒冷地区城市公园老年人秋季热舒适特征及影响因素分析

为进一步明确寒冷地区城市公园老年人秋季热舒适特征及影响因素,结合微气候实测和热舒适调研的方法,通过与非老年人进行对比,分析了老年人室外热感觉与热舒适的关系特征,从热中性生理等效温度(physiological equivalent temperature,PET)、满足80%热可接受率的PET范围以及热偏好PET 3个方面,划定了老年人热舒适评价标准,并探明了微气候因素对老年人热舒适的影响特征。结果表明:寒冷地区秋季城市公园中,相较于非老年人,老年人的耐热性较强,耐寒性较弱;老年人的热中性PET为8.3℃,非老年人为11.5℃,热可接受PET范围为3.2~28.0℃,非老年人为4.9~24.3℃,热偏好PET为25.8℃,非老年人为24.2℃;各微气候因素对老年人热感觉的影响程度由大到小依次为黑球温度>风速>相对湿度。

夏季华东地区室外热舒适经验指标模型建立

伴随国民经济水平的提高,室外的热舒适水平逐渐受到民众的广泛关注。尤其是在经济发达的华东地区,人口密集,夏季的炎热气候严重影响了民众在室外空间的热舒适与体验。已有研究表明,在一些地区,基于当地调研数据建立的经验指标模型能够更好地预测当地民众的室外热舒适状况。因此,文章对华东地区代表性城市金华市展开微气候环境测量与问卷调查,利用统计学方法多元回归对调研数据进行分析,最终建立经验指标模型并验证其适用性。研究结果表明,在回归分析得出的三个模型中,选取拟合度最优的模型为经验指标模型,具体公式为:TSV_(model)=0.228T_(a)-0.211V+0.201T_(g)-13.947(R^(2)=0.715,P<0.001)。所得经验指标模型为夏季华东地区基于室外热舒适的空间优化设计研究提供了评价指标选择的参考。

寒冷地区典型办公园区室外热舒适研究

办公建筑作为城市中常见的建筑类型,是城市居民的重要活动场所,室外热环境的改善能够有效提升办公园区的空间品质。选取大连市典型办公园区作为研究对象,采用类型学研究方法,以通用热气候指数(Universal Thermal Climate Index,UTCI)与热舒适预测平均投票数(Predicted Mean Vote,PMV)作为评价指标,通过软件模拟不同围合度条件下办公园区热舒适的分布情况。结果表明:①以平面围合程度作为划分依据,将研究样本按照围合程度从低到高分为点式、板式、L字型、U字型、庭院型、复合型六大类。②在建筑参数相近的条件下,随着建筑组团围合度的提高,办公园区建筑场地内的室外热舒适度越高,即场地热舒适度从高到低排序为:复合式>庭院式>U字型>L字型>板式>点式。在仅考虑室外热舒适度的情况下,寒冷地区办公建筑适合围合度高(复合型、庭院型、U字型)的建筑形式。

室外热舒适研究综述——基于Web of Science文献的知识图谱分析

良好的室外热环境有利于激发户外体力活动进而促进人体健康,并降低建筑能耗。文章利用Cite Space科学知识可视化图谱软件对2008—2023年Web of Science核心数据库检索到的1450篇“outdoor thermal comfort”研究相关文献,进行科技文本挖掘及可视化分析。结果表明:(1)室外热舒适的研究主要集中于热舒适、室外热环境、ENVI-met模拟、CFD模拟等方面;(2)移动测量、声学舒适度、空气污染成为近年室外热舒适研究热点,研究前沿方向集中于公共空间以及夏季炎热地区的热舒适研究;(3)越来越多的热舒适研究选择使用软件模拟和实地测量相结合的研究方法,目前普遍采用ENVI-met作为主要模拟工具表明该软件被普遍用于热舒适研究。

基于局地气候区的校园室外热舒适影响因素及优化策略研究

气候变化背景下校园室外热环境的重要性凸显,迫切需要科学的设计指引以提升校园热环境。然而,当前研究多局限于单一空间或室内环境,缺乏多空间的对比研究,忽略了室外热环境多要素相互影响的复杂特性。基于此,研究基于局地气候区理论,选取了3类开放空间和3类建成环境,结合实测和问卷调研探究校园室外热舒适关键影响因素,进而提出针对性的优化策略,以期为夏热冬暖地区校园室外热环境营造提供设计指引。

夏热冬冷地区养老院老年人冬季室外热舒适性探究

养老院室外空间是机构养老人群的主要室外活动场所,室外空间的热舒适性对老年人身心健康具有重要影响。为营造健康、舒适的室外热环境,文章以上海Q养老院为例,通过对养老院室外热环境实测和老年人室外热舒适问卷调查,分析老年人室外热舒适与热感觉关系,研究热环境因素对老年人冬季室外热舒适的影响,从热中性生理等效温度、热中性生理等效温度范围、满足90%热可接受率的生理等效温度范围和热偏好生理等效温度等4个方面,确定老年人冬季热舒适性评价基准;最后基于研究结果,从自然环境和建筑环境两方面提出养老院冬季室外热环境优化设计建议,为夏热冬冷地区养老院室外热环境改善提供参考。

Data generative machine learning model for the assessment of outdoor thermal and wind comfort in a northern urban environment

Predicting comfort levels in cities is challenging due to the many metric assessment.To overcome these challenges,much research is being done in the computing community to develop methods capable of generating outdoor comfort data.Machine Learning(ML)provides many opportunities to discover patterns in large datasets such as urban data.This paper proposes a data-driven approach to build a predictive and data-generative model to assess outdoor thermal comfort.The model benefits from the results of a study,which analyses Computational Fluid Dynamics(CFD)urban simulation to determine the thermal and wind comfort in Tallinn,Estonia.The ML model was built based on classification,and it uses an opaque ML model.The results were evaluated by applying different metrics and show us that the approach allows the implementation of a data-generative ML model to generate reliable data on outdoor comfort that can be used by urban stakeholders,planners,and researchers.

湿热地区老年人公园热舒适的环境因素

城市公园是老年人户外活动的主要场所,公园环境的热舒适与老年人身心健康息息相关。文章以湿热地区城市公园老年人为对象,针对休憩类活动场地进行热环境测量与问卷调查,探讨影响老年人夏季室外热舒适的公园环境因素。结果表明:(1)遮荫与水体对老年人室外热感觉影响较大,且利于维持微气候稳定性;(2)热参数水平接近时,降低太阳辐射仍可从心理上有效改善老年人“热感”,乔木比建筑遮荫更能减少太阳辐射、降低热中性PET值,提高热舒适性;(3)老年人在夏季喜欢“偏凉”的热环境,对风速需求强,对湿度的可接受度较高,水体是改善老年人热舒适的重要因素。基于研究结果,从选址规划、空间布局及环境要素3个方面提出城市公园环境设计启示,为湿热地区城市公园的热环境适老化提供借鉴。

街谷行道树种植对环境热舒适度的影响及适应性设计研究进展

行道树种植通常被作为改善城市街谷近地微气候的重要策略,如何发挥行道树对街谷热舒适度的提升潜力受到诸多学者的广泛关注。近年来“行道树种植与街谷热舒适度”相关研究获得了丰硕成果,通过总结梳理可将其归纳为行道树树木个体形态对热舒适度的调控、行道树绿带空间配置与街谷热舒适度整体提升的关联性、适应不同街谷空间形态的行道树种植设计策略等三个研究主题。在深入分析既有研究成果基础上,提出了一套改善热舒适度的街谷行道树种植设计方案技术框架。最后,分别从建立响应地域气候特征的街谷行道树种植设计模式、构建街谷环境热舒适度模拟评估导则、制定街谷环境热舒适度评价标准等方面开展深入讨论,以期为后续城市街谷绿化提升热环境的研究提供思路和借鉴。

基于行为活动的居住区室外公共空间热舒适性及热环境优化策略研究——以武汉典型居住区为例

以武汉典型居住区室外公共空间为研究范围,采用实测与问卷调查获得的室外热环境参数数据、使用者的热舒适性投票为数据来源,通过分析武汉地区居民室外活动特征和室外热舒适性特点,以及空间使用率与热舒适指标的关联性,探讨活动类型差异对热舒适适应性的影响。研究发现:公共空间的天空可视因子值越高,热舒适指标水平越高;社会性活动对于热环境变化的敏感性低于自发性活动;空间使用率与热舒适指标之间存在二次抛物线关系。最后,提出差异化的居住区室外公共空间热舒适性改善策略。

Effects of mask wearing duration and relative humidity on thermal perception in the summer outdoor built environment

During the pandemic,face masks are one of the most significant self-protection necessities,but they also cause heat stress.By using the ERA5(ECMWF Reanalysis 5th Generation)database and the local weather bureau data,the effect of mask wearing on outdoor thermal sensation has been investigated by a survey conducted in the hot summer and cold winter region of eastern China in the summer of 2020.Results show that wearing a face mask for a longer period result in a higher level of discomfort,and the primary source of discomfort is hot and stuffy feelings.The effect of relative humidity is crucial for mask wearers in warm-biased thermal environments,as mean thermal sensation vote(TSV)peaks when environmental relative humidity reaches the range of 70%to 80%and decreases after this range due to the evaporation within the microclimate created by a face mask.Meanwhile,prolonged mask wearing increases participants’hot feelings,especially in warm environments.Specifically,participants wearing face masks for less than 30 min feel hot at a physiological equivalent temperature(PET)value of 34.4℃,but those who wear them for over 60 min express hot feelings even at a PET value of 24.7℃.The participants who wear a face mask while walking slowly outdoors have similar thermal sensations to those who do not wear a mask,but are in a higher activity level.The findings demonstrate that mask wearing has a crucial impact on outdoor thermal comfort assessment in a warm-biased outdoor thermal environment.

夏热冬冷地区室外广场空间冬季热舒适研究

随着城市发展及居民室外活动时间不断增多,良好的室外空间环境及热舒适性对居民身心健康具有重要影响。针对关注较少的冬季室外环境热舒适问题,以夏热冬冷地区的重庆三峡广场为例,基于冬季热环境实测和热舒适问卷调查,利用Rayman软件计算PET(生理等效温度值)作为热舒适评价参数,建立TCV(热舒适投票值)、TSV(热感觉投票值)与PET的函数关系式,得到不同室外环境空间的冬季热舒适范围,提出适用于夏热冬冷地区的冬季综合舒适度评价模型。研究成果可为完善夏热冬冷地区的室外热舒适研究提供基础数据参考。

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。

夏热冬暖地区高校校前广场微气候改造策略研究——以广州大学校前广场为例

后疫情时代,部分高校实施封闭式管理,校园环境质量的好坏密切影响着师生的身心健康。以往高校校园空间比较注重轴线布局的形式感,对空间的舒适性关注不够,也忽视了景观要素对室外热环境的影响,未充分发挥校景观要素在生态建设方面的作用,对场地的热舒适潜力挖掘不足。在既有校园空间中,校园前广场作为校园的重要空间节点,其形象在师生意识中已根深蒂固,在不影响校园前广场形象的前提下,有必要对其当前的热舒适性进行研究,并通过热缓解策略发掘其热舒适的提升潜力。本文通过ENVI-met模拟软件对不同改造情景下的校前广场进行微气候模拟,并分析各改造策略在冬夏两季对广场热舒适的改善效果。