Improvement of the Outdoor Thermal Comfort by Water Spraying in a High-Density Urban Environment under the Influence of a Future (2050) Climate

2021 ◽  
Vol 13 (14) ◽  
pp. 7811
Author(s):  
Ka-Ming Wai ◽  
Lei Xiao ◽  
Tanya Zheng Tan
Keyword(s):  
Climate Change ◽  
Thermal Comfort ◽  
Thermal Sensation ◽  
Ambient Air ◽  
Outdoor Thermal Comfort ◽  
Future Climate Change ◽  
Physiological Equivalent Temperature ◽  
Adaptation Measures ◽  
Prevailing Wind Direction ◽  
The Impact

Adaptation to prepare for adverse climate change impacts in the context of urban heat islands and outdoor thermal comfort (OTC) is receiving growing concern. However, knowledge of quantitative microclimatic conditions within the urban boundary layer in the future is still lacking, such that the introduction of adequate adaptation measures to increase OTC is challenging. To investigate the cooling performance of a water spraying system in a sub-tropical compact and high-rise built environment in summer under the influence of future (2050) climatic conditions, results from two validated models (Weather Research and Forecast (WRF) and ENVI-met models) have been used and analyzed. Our results indicate that the spraying system provides cooling of 2–3 °C for ambient air temperature at the pedestrian-level of the urban canyons considered here, which benefits pedestrians. However, improvement of the OTC in terms of the physiological equivalent temperature (PET—a better indicator of human thermal sensation) was noticeable (e.g., <42 °C or from very hot to hot) when the urban canyon was orientated parallel to the prevailing wind direction only. This implies that in order to improve city resilience in terms of heat stress, more holistic adaptation measures in urban planning are needed. This includes the introduction of more breezeways and building disposition to facilitate the urban ventilation, as well as urban tree arrangement and sunshades to reduce direct solar radiation to plan for the impact of future climate change.

Implications of Building Material Choice on Outdoor Microclimate for Sustainable Built Environment

2015 ◽  
Vol 650 ◽  
pp. 82-90 ◽  
Author(s):  
D. Kannamma ◽  
A. Meenatchi Sundaram
Keyword(s):  
Thermal Comfort ◽  
Building Material ◽  
Building Materials ◽  
Climatic Factors ◽  
Outdoor Environment ◽  
Outdoor Thermal Comfort ◽  
Physical Factors ◽  
Physiological Equivalent Temperature ◽  
Material Choice ◽  
The Impact

The climatic conditions in a man-made urban environment may differ appreciably from those in the surrounding natural or rural environs.... each urban man-made buildings, roads, parking area, factories......creates around and above it a modified climate with which it interacts [1].Outdoor thermal comfort has gained importance in thermal comfort studies especially in tropical countries. In country like India, culturally the activities are spread both indoors and outdoors. Therefore the need for ambient outdoor environment gains importance. As there are many factors that contribute to outdoor thermal comfort (climatic factors and physical factors), this study aims in analyzing the impact of building material contribution, in an institutional courtyard. In order to understand the thermal contribution of various building materials and to suggest material choice to designers, ENVIMET is used for simulation purpose. The outdoor thermal comfort index employed in this study is PET (Physiological Equivalent Temperature), calibrated using RAYMAN.

scholarly journals Assessing The Thermal Comfort Conditions In Open Spaces: A Transversal Field Survey On The University Campus In India

2021 ◽  
Vol 8 (3) ◽  
pp. 77-92
Author(s):  
Pardeep Kumar ◽  
Amit Sharma
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Arid Regions ◽  
Thermal Sensation ◽  
Probit Analysis ◽  
Outdoor Thermal Comfort ◽  
Cold Weather ◽  
Open Spaces ◽  
Physiological Equivalent Temperature ◽  
Preferred Temperature

Outdoor thermal comfort (OTC) promotes the usage frequency of public places, recreational activities, and people's wellbeing. Despite the increased interest in OTC research in the past decade, less attention has been paid to OTC research in cold weather, especially in arid regions. The present study investigates the OTC conditions in open spaces at the campus area in the arid region. The study was conducted by using subjective surveys(questionnaire) and onsite monitoring (microclimate parameters). The study was conducted at the Deenbandhu Chhotu Ram University of Science and Technology, Murthal, Haryana-India campus during the cold season of 2019. The timings of surveys were between 9:00 and 17:00 hours. The authors processed the 185 valid questionnaire responses of the respondents to analyze OTC conditions. Only 8.6% of the respondents marked their perceived sensation "Neutral." Regression analysis was applied between respondents' thermal sensations and microclimate parameters to develop the empirical thermal sensation model. The air temperature was the most dominant parameter affecting the sensations of the respondents. The empirical model indicated that by increasing air temperature, relative humidity, and solar radiation, the thermal sensations also increased while wind speed had an opposite effect. Physiological equivalent temperature (PET) was applied for assessing the OTC conditions; the neutral PET range was found to be 18.42-25.37°C with a neutral temperature of 21.89°C. The preferred temperature was 21.99 °C by applying Probit analysis. The study's findings could provide valuable information in designing and planning outdoor spaces for educational institutions in India's arid regions

Outdoor thermal comfort in a tropical coastal tourist resort in Haikou, China

2019 ◽  
Vol 29 (5) ◽  
pp. 730-745 ◽  
Author(s):  
Chunjing Shang ◽  
Xinyu Huang ◽  
Yufeng Zhang ◽  
Maoquan Chen
Keyword(s):  
Solar Radiation ◽  
Thermal Comfort ◽  
Thermal Sensation ◽  
Outdoor Thermal Comfort ◽  
Survey Period ◽  
Physiological Equivalent Temperature ◽  
Local Climate ◽  
Acceptable Range ◽  
Tropical Areas ◽  
Autumn And Winter

Considering the importance of thermal comfort in decision-making in tourism, a transverse study involving micrometeorological measurements and questionnaires was performed at a popular coastal destination during the seasons of spring, autumn and winter. We examined the thermal sensation and thermal acceptability using the physiological equivalent temperature (PET). The results indicate that tourists’ thermal sensations varied with the season and the neutral PETs were 19.2°C, 23.8°C and 23.3°C in winter, spring and autumn. The 90% acceptable ranges of the PET affected by the local climate were 19.6–29.5°C during the entire three-season survey period, 21.4–27.1°C in the spring, 19.2–32°C in the autumn and more than 15.9°C in the winter. The analysis of microclimate parameters that affect thermal comfort in three seasons reveals that people expected weaker solar radiation, stronger wind and lower humidity with the air temperature rising, and vice versa. The acceptable range of wind speed was 0.6–2.5 m/s in winter, 0.6–3.5 m/s in spring and autumn. The acceptable range of solar radiation was 0–150 W/m2 in autumn and 0–250 W/m2 in winter. These findings contribute to the better designs for coastal facilities and the thermal comfort of tropical areas.

scholarly journals Thermal Sensation in Courtyards: Potentialities as a Passive Strategy in Tropical Climates

2020 ◽  
Vol 12 (15) ◽  
pp. 6135 ◽  
Author(s):  
Ivan Julio Apolonio Callejas ◽  
Luciane Cleonice Durante ◽  
Eduardo Diz-Mellado ◽  
Carmen Galán-Marín
Keyword(s):  
Climate Change ◽  
Urban Areas ◽  
Thermal Sensation ◽  
Thermal Response ◽  
Tropical Climate ◽  
Design Strategies ◽  
Physiological Equivalent Temperature ◽  
Synoptic Conditions ◽  
The Impact ◽  
Passive Strategy

Climate change will bring changes to our living conditions, particularly in urban areas. Climate-responsive design strategies through courtyards can help to moderate temperatures and reduce the thermal stress of its occupants. Thermal response inside courtyard is affected not only by its morphological composition but also by subjective factors. Thus, standardized thermal scales may not reflect the stress of the occupants. This study investigated the impact on thermal attenuation provided by a courtyard located in a tropical climate under extreme cold and hot synoptic conditions by means of local thermal sensation scales. Microclimatic variables were monitored, simultaneously with the application of a thermal comfort questionnaire, by using weather stations installed outside and inside the courtyard. The Modified Physiological Equivalent Temperature Index (mPET) was utilized to predict the heat stress. Calibration was conducted using linear regression to attribute particular thermal sensation votes to correspondent mPET values. It was found that thermal sensation can be affected by factors such as psychological, behavioral, and physiological. The courtyard’s form provides a passive cooling effect, stabilizing interior thermal sensation, with attenuation peaks of 6.4 °C on a cold day and 5.0 °C on a hot day. Courtyards are an alternative passive strategy to improve thermal ambience in tropical climate, counterbalancing climate change.

scholarly journals In-situ Measurement of Pedestrian Outdoor Thermal Comfort in Universities Campus of Malaysia

2019 ◽  
Author(s):  
Nurnida Elmira Othman ◽  
Sheikh Ahmad Zaki ◽  
Nurul Huda Ahmad ◽  
Azli Razak
Keyword(s):  
Thermal Comfort ◽  
Field Measurement ◽  
Thermal Sensation ◽  
Outdoor Thermal Comfort ◽  
View Factor ◽  
Thermal Preference ◽  
Equivalent Temperature ◽  
Physiological Equivalent Temperature ◽  
Sky View Factor

The present study is intended to evaluate an outdoor thermal comfort at two universities campus in Malaysia. Field measurement and questionnaire survey were conducted simultaneously to assess the microclimatic condition and pedestrian thermal sensation. A total of 3033 samples were collected at seven different sky view factor (SVF) values that range from 0.2 to 0.9. The physiological equivalent temperature (PET) was estimated to evaluate outdoor thermal comfort. It was observed that at a highly shaded area (SVF < 0.35) the respondent’s thermal sensation vote (TSV) are neutral (> 25%), acceptable for thermal acceptance vote (TAV) (> 50%) and no change (> 50%) for thermal preference vote (TPV). For moderate shaded (0.35 ≤ SVF ≤ 0.70) TSV was voted as hot (> 25%), acceptable for TAV (40%), and prefer slightly cooler for TPV (>50%). For less shaded area (0.70 < SVF ≤ 1), TSV was voted as hot and very hot (> 25%), acceptable for TAV (>40%) and prefer slightly cooler for TPV (> 40%). Moreover, the PET value increases simultaneously with the increase of SVF. Results thus suggest that at any given activities such as sitting, walking, and standing also caused effects slightly on the way people thermally perceive it during the on-campus daytime.

scholarly journals Correlative Impact of Shading Strategies and Configurations Design on Pedestrian-Level Thermal Comfort in Traditional Shophouse Neighbourhoods, Southern China

2019 ◽  
Vol 11 (5) ◽  
pp. 1355 ◽  
Author(s):  
Shi Yin ◽  
Werner Lang ◽  
Yiqiang Xiao ◽  
Zhao Xu
Keyword(s):  
Thermal Stress ◽  
Thermal Comfort ◽  
Southern China ◽  
Simulation Models ◽  
Outdoor Thermal Comfort ◽  
Humid Climate ◽  
Physiological Equivalent Temperature ◽  
Axis Orientation ◽  
Covered Area ◽  
The Impact

Traditional shophouse neighbourhoods (TSNs) in southern China respond well to the local hot and humid climate through proper street configurations and the integration of different shading strategies. Investigating the impact of shading strategies and configurations in TSNs on outdoor thermal comfort is valuable for guiding current urban design. Three street canyons in a TSN of Guangzhou with different shading strategies were selected as basic cases for microclimatic measurement in the summer season, i.e., alleys, streets with arcade for pedestrians, and streets with high-density greenery. After validating their simulation models in ENVI-met, five groups of parametric simulations were generated by varying the canyon aspect ratio (CHW), the canyon axis orientation, arcade proportion (AHW), and the tree-covered area (TCA). Using the physiological equivalent temperature (PET) to assess the above results, the correlative impact of different variations on pedestrian’s thermal comfort and their corresponding favourable ranges are summarized. The findings suggest that: (a) only in alleys and arcade streets, the pedestrian-level thermal comfort was significantly influenced by canyon axis orientation. (b) The thermal stress for pedestrians increased dramatically when the CHW was lower than 1.5 in alleys and 0.78 in boulevards (in TCA = 89%), while the CHW higher than 1 indicated a remarkable reduction on the PET for pedestrians in arcades. (c) The pedestrians started losing the protection from shading strategy to thermal stress when the AHW was higher than 1.33 (in canyon with CHW = 1) or the TCA was lower than 33% (in canyon with CHW = 0.78).

scholarly journals Quantification of the Outdoor Thermal Comfort within Different Oases Urban Fabrics

2021 ◽  
Vol 13 (6) ◽  
pp. 3051
Author(s):  
Mohamed Elhadi Matallah ◽  
Djamel Alkama ◽  
Jacques Teller ◽  
Atef Ahriz ◽  
Shady Attia
Keyword(s):  
Climate Change ◽  
Thermal Comfort ◽  
Urban Sprawl ◽  
Green Infrastructure ◽  
Outdoor Thermal Comfort ◽  
Physiological Equivalent Temperature ◽  
Climate Change Effects ◽  
Mitigation And Adaptation ◽  
Study Results ◽  
Desert Regions

Oases settlements are common entities of human agglomerations throughout desert regions. Oases settlements face several environmental challenges such as climate change, which can render them insufferably hot and unlivable within decades. Therefore, this study aims to assess the outdoor thermal comfort variation within three different oases urban fabrics of Tolga Oases Complex in Algeria. The overarching aim is to quantify thermal comfort and guide landscape, and urban designers improve outdoor thermal comfort. The methodology relies on microclimatic measurements and weather datasets (TMY2, TMY3, TMYx), combining observations and numerical simulations. A total of 648 Physiological Equivalent Temperature (PET) values were calculated in three different urban fabrics in Tolga Oases Complex, Algeria. Between 2003 and 2017, a remarkable microclimatic change was found, causing a high and accelerated heat stress level of 76%. The study results inform architects, urban planners and climatologists about climate change effects and urban sprawl impact on the oases lands. Moreover, urban strategies should seek mitigation and adaptation benefiting from the existing green infrastructure of palm groves.

scholarly journals Outdoor Thermal Comfort of Urban Park—A Case Study

2020 ◽  
Vol 12 (5) ◽  
pp. 1961 ◽  
Author(s):  
Lili Zhang ◽  
Dong Wei ◽  
Yuyao Hou ◽  
Junfei Du ◽  
Zu’an Liu ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Urban Areas ◽  
Thermal Sensation ◽  
Urban Parks ◽  
Living Environment ◽  
Outdoor Thermal Comfort ◽  
Climate Index ◽  
Urban Residents ◽  
Physiological Equivalent Temperature ◽  
Different Types

Urban parks are an important component of urban public green space and a public place where a large number of urban residents choose to conduct outdoor activities. An important factor attracting people to visit and stay in urban parks is its outdoor thermal comfort, which is also an important criterion for evaluating the liability of the urban environment. In this study, through field meteorological monitoring and a questionnaire survey, outdoor thermal comfort of different types of landscape space in urban parks in Chengdu, China was studied in winter and summer. Result indicated that (1) different types of landscape spaces have different thermal comforts, (2) air temperature is the most important factor affecting outdoor thermal comfort; (3) because the thermal sensation judgment of outdoor thermal comfort research in Chengdu area, an ASHRAE seven-sites scale can be used; (4) the neutral temperature ranges of Physiological Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) in Chengdu in winter and summer were obtained through research; (5) and UTCI is the best index for evaluating outdoor thermal comfort in Chengdu. These findings provide theoretical benchmarks and technical references for urban planners and landscape designers to optimize outdoor thermal comfort in urban areas to establish a more comfortable and healthy living environment for urban residents.

scholarly journals A Field Investigation on Adaptive Thermal Comfort in an Urban Environment Considering Individuals’ Psychological and Physiological Behaviors in a Cold-Winter of Wuhan

2021 ◽  
Vol 13 (2) ◽  
pp. 678
Author(s):  
Mehdi Makvandi ◽  
Xilin Zhou ◽  
Chuancheng Li ◽  
Qinli Deng
Keyword(s):  
Thermal Comfort ◽  
Large Scale ◽  
Thermal Sensation ◽  
Field Investigation ◽  
Outdoor Thermal Comfort ◽  
Sustainable Urban Development ◽  
Physical Factors ◽  
Cold Winter ◽  
Physiological Equivalent Temperature ◽  
Clothing Insulation

To date, studies of outdoor thermal comfort (OTC) have focused primarily on physical factors, tending to overlook the relevance of individual adaptation to microclimate parameters through psychological and physiological behaviors. These adaptations can significantly affect the use of urban and outdoor spaces. The study presented here investigated these issues, with a view to aiding sustainable urban development. Measurements of OTC were taken at a university campus and in urban spaces. Simultaneously, a large-scale survey of thermal adaptability was conducted. Two groups were selected for investigation in a cold-winter-and-hot-summer (CWHS) region; respondents came from humid subtropical (Cfa) and hot desert (BWh) climates, according to the Köppen Climate Classification (KCC). Results showed that: (1) neutral physiological equivalent temperature (NPET) and preferred PET for people from the Cfa (PCfa) and BWh (PBWh) groups could be obtained with KCC; (2) PCfa adaptability behaviors were, subjectively, more adjustable than PBWh; (3) Clothing affected neutral temperature (NT), where NT reduced by approximately 0.5 °C when clothing insulation rose 0.1 Clo; and (4) Gender barely affected thermal acceptance vote (TAV) or thermal comfort vote (TCV) and there was a substantial relationship between thermal sensation, NT, and PET. These findings suggest ‘feels like’ temperature and comfort may be adjusted via relationships between microclimate parameters.

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