scholarly journals Investigating micrometeorological differences between saline steppe, forest-steppe and forest environments in northern Serbia during a clear and sunny autumn day

2020 ◽  
Vol 24 (3) ◽  
pp. 176-186
Author(s):  
Dragan Milošević ◽  
Jelena Dunjić ◽  
Vladimir Stojanović
Keyword(s):  
Thermal Comfort ◽  
Endemic Species ◽  
Early Morning ◽  
Outdoor Thermal Comfort ◽  
Forest Steppe ◽  
Natural Environments ◽  
Wind Speeds ◽  
The North ◽  
Saline Habitats ◽  
Autonomous Province

Saline habitats of the Pannonian plain are specific regarding their extraordinary biodiversity with many endemic species, yet they are among the most threatened European Communities with limited spatial distribution. These habitats are present in the Autonomous Province of Vojvodina in the North of Serbia, in the area of Srednja Mostonga, and they are in the procedure of protection as the II category protected area - "region of exceptional characteristics". Great variety of rare and endemic species makes this area interesting for recreational and educational activities. In this paper we investigate micrometeorological and outdoor thermal comfort conditions in different natural environments at the area of Srednja Mostonga. This is the first micrometeorological field measurement study conducted in this region. Measurements were performed during the daytime of a sunny autumn day in 2019. The results showed that daytime air temperature was up to 3.4 °C lower in forest compared to steppe, while relative humidity was up to 5-6% higher in forest than in steppe with up to 3.2 m/s lower wind speeds in forest than in steppe area. Micrometeorological values were similar between forest-steppe and steppe. However, the outdoor thermal comfort conditions expressed via Humidex showed that 'some discomfort' was most often observed in forest-steppe during 27% of measurement time, followed with 13% of 'some discomfort' observed in steppe and only 1% of 'some discomfort' was observed in forest. Accordingly, during the warmest daytime hours outdoor activities could be performed in forest, while early morning and evening hours could be spent in steppe and forest-steppe areas of Srednja Mostonga.

Study on Design Strategies for Improving Outdoor Thermal Comfort in the Cold Regions of China

2011 ◽  
Vol 250-253 ◽  
pp. 3798-3801 ◽  
Author(s):  
Jing Li ◽  
Yu Liu
Keyword(s):  
Thermal Comfort ◽  
North China ◽  
Outdoor Environment ◽  
Outdoor Thermal Comfort ◽  
Design Strategies ◽  
Cold Regions ◽  
Winter Climate ◽  
Thermal Environments ◽  
The North ◽  
Xi’An City

Along with the improvement of dwelling quality, the length of time and frequency of outdoor activities in winter greatly increase in the north China area, although the outdoor thermal environments are still unsatisfactory. It is necessary for both planners and architects to improve outdoor thermal environments in the cold regions of north China. This paper firstly introduces the general winter climate features in some north China cities. Then, it takes Xi'an city as an example to show the shortage of uncomfortable outdoor environment. Thirdly, the design strategies to improve outdoors thermal comfort include wind and snow protection, sunlight usage, environmental zones and recreational facilities, etc. are discussed.

scholarly journals The Effect of Street Orientation on Outdoor Thermal Comfort in a Cold Mountainous Climate

2021 ◽  
Author(s):  
Narges Delpak ◽  
Hassan Sajadzadeh ◽  
Saide Hasanpourfard ◽  
Farshid Aram
Keyword(s):  
Thermal Comfort ◽  
Urban Spaces ◽  
Outdoor Thermal Comfort ◽  
Mean Radiant Temperature ◽  
Direct Sunlight ◽  
Physiological Equivalent Temperature ◽  
The North ◽  
Radiant Temperature ◽  
Climatic Characteristics ◽  
New Settlements

Lack of due attention to the orientation of streets and establishment of urban blocks without regard for climatic characteristics and conditions of the environment have an adverse effect on thermal comfort in open urban spaces. Construction of new settlements without taking into account climatic requirements undermines thermal comfort for pedestrians and other users, especially in cold regions. Considering the coldness of the region under study and the significance of the orientation of streets in absorbing radiation and providing heat to outdoor urban spaces, this study investigates the effect of the orientation of streets on microclimatic comfort in one of the residential towns of Hamadan City in Iran. For this purpose, microclimate simulation was performed using ENVI-met software. A residential block with four different orientations (the most common orientations of its surrounding buildings) were simulated in the coldest day of winter and the hottest day of summer. The results suggest that streets have different thermal behavior in different orientations. Orientation affects mean radiant temperature (Tmrt), the duration of exposure to direct sunlight, wind speed, and physiological equivalent temperature (PET), which are all important factors in thermal comfort. Based on these findings, north-south streets in Hamedan receive more radiant temperature during winter compared to other simulated orientations and provide more desirable thermal comfort. The average PET value on a winter day at a point on the north-south passage was 4.5-8 °C warmer than other orientations. In summer, streets with intercardinal orientations (i.e., northeast-southwest and northwest-southeast) provided the lowest PET (about 2 °C cooler than other orientations) and better thermal comfort

scholarly journals Evaluation of Subjective Feelings of Outdoor Thermal Comfort in Residential Areas: A Case Study of Wuhan

Buildings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 389
Author(s):  
Kun Li ◽  
Tingting Xia ◽  
Wenya Li
Keyword(s):  
Thermal Comfort ◽  
Meteorological Parameter ◽  
Central China ◽  
Outdoor Thermal Comfort ◽  
Residential Areas ◽  
Daily Lives ◽  
Object A ◽  
Wind Speeds ◽  
Level Of Satisfaction ◽  
Temperature Sensations

Outdoor thermal comfort in urban residential areas is closely related to the daily lives of their residents. Nine residential communities in Wuhan, a typical city in central China, were selected as the research object. A questionnaire survey, meteorological parameter measurements, and data analyses were used to investigate the influences of factors such as the characteristics of the spatial environments and the types of outdoor activities undertaken by the residents on the levels of comfort. This investigation was expected to provide a reference for improving these levels. The results show that the level of satisfaction of those in areas with building heights of more than 15 stories reached 51%. Wind speeds were higher in medium-density areas while comfort was the highest in residential areas with densities between 22% and 30%. High-quality areas, which benefitted mainly from higher sensations of wind speed, had the highest levels of comfort but the strongest sensations of heat. A positive correlation exists between green areas and comfort. Where the green coverage rate exceeded 70.0%, temperature satisfaction increased to 33.3–66.7%. Areas with impervious paving are negatively correlated to temperature sensations. Areas of 400–625 m2 had levels of temperature satisfaction lower than 21.5%.

Investigation on thermal comfort of the uniform for workers in tropical monsoon climates

2020 ◽  
Vol 32 (6) ◽  
pp. 849-868
Author(s):  
Jingxian Xu ◽  
Huijuan Liu ◽  
Yunyi Wang ◽  
Jun Li
Keyword(s):  
Heat Transfer ◽  
Thermal Comfort ◽  
Dynamic Condition ◽  
Thermal Manikin ◽  
Content Type ◽  
Wind Speeds ◽  
Subjective Perceptions ◽  
Tropical Monsoon ◽  
Four Levels ◽  
Thermal Insulations

PurposeThis study aims to investigate the heat transfer mechanism of the uniforms used by people working in hot, humid and windy environments. Furthermore, the effectiveness of an opening structure added to the armpit of the uniforms in improving thermal comfort was comparatively examined.Design/methodology/approachA set of uniforms was tested with the opening at the armpit alternatively zipped or unzipped. Thermal manikin and human tests were performed in a climatic chamber simulating the specific environmental conditions, including wind speeds at four levels (0.15, 0.5, 2, 4 m/s) and relative humidities at two levels (50 and 85%). Static and dynamic thermal insulations of clothing (IT) were examined by the thermal manikin tests. The human bodies' thermal responses, including heart rates (HR), eardrum temperatures (Te), skin temperatures (Tsk) and subjective perceptions, were given by the human tests.FindingsSpecial mechanisms of heat transfer in the specific uniforms used in tropical monsoon climates were revealed. Reductions on IT were caused by the movement of the human body and the environmental wind, and the empirical equations would underestimate this reduction. The opening at the armpit was able to prompt more heat transfer under dynamic condition, with reducing the IT by 11.8%, lowering the mean Tsk by 0.92°C, and significantly improving the subjective perceptions (p < 0.05). The heat exhaustion was alleviated with lowering the Te by 0.32°C.Originality/valueThis study managed to improve the thermal performance of uniforms for workers under unforgiving conditions. The evaluation and design methods introduced by this study provided practical guidance for similar products with strict dress codes and cost control requirements based on the findings from thorough product tests and analysis.

scholarly journals Urban Heat Islands and Thermal Comfort: A Case Study of Zorrotzaurre Island in Bilbao

2021 ◽  
Vol 13 (11) ◽  
pp. 6106
Author(s):  
Irantzu Alvarez ◽  
Laura Quesada-Ganuza ◽  
Estibaliz Briz ◽  
Leire Garmendia
Keyword(s):  
Thermal Comfort ◽  
Heat Waves ◽  
Urban Environments ◽  
Urban Heat Islands ◽  
Extreme Weather Events ◽  
Climate Index ◽  
Physiological Equivalent Temperature ◽  
Heat Islands ◽  
The North ◽  
The Impact

This study assesses the impact of a heat wave on the thermal comfort of an unconstructed area: the North Zone of the Island of Zorrotzaurre (Bilbao, Spain). In this study, the impact of urban planning as proposed in the master plan on thermal comfort is modeled using the ENVI-met program. Likewise, the question of whether the urbanistic proposals are designed to create more resilient urban environments is analyzed in the face of increasingly frequent extreme weather events, especially heat waves. The study is centered on the analysis of temperature variables (air temperature and average radiant temperature) as well as wind speed and relative humidity. This was completed with the parameters of thermal comfort, the physiological equivalent temperature (PET) and the Universal Temperature Climate Index (UTCI) for the hours of the maximum and minimum daily temperatures. The results demonstrated the viability of analyzing thermal comfort through simulations with the ENVI-met program in order to analyze the behavior of urban spaces in various climate scenarios.

scholarly journals Ag/VO2/Ag sandwich nylon film for smart thermal management and thermo-responsive electrical conductivity

2021 ◽  
pp. 152808372098654
Author(s):  
Linghui Peng ◽  
Lingling Shen ◽  
Weiren Fan ◽  
Zichuan Liu ◽  
Hongbo Qiu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Thermal Comfort ◽  
Thermal Management ◽  
Flexible Electronics ◽  
Sandwich Structure ◽  
Outdoor Thermal Comfort ◽  
Ir Radiation ◽  
Indoor Space ◽  
Layer Structures ◽  
Radiation Management

Due to the effects of climate changing, the importance of outdoor thermal comfort has been recognized, and has gained more and more research attentions. Unlike indoor space where air conditioning can be easily implemented, outdoor thermal comfort can only be achieved by localized thermal management. Using textile is a simple but energy-saving way to realize outdoor thermal comfort. Herein, we report the design of a smart thermal management film with the silver/vanadium dioxide/silver (Ag/VO2/Ag) sandwich structure prepared by one-dimensional (1 D) nanowires. It was found that the Ag/VO2/Ag sandwich film was able to lower the temperature by around 10 °C under intense infrared (IR) radiation. In addition, the Ag/VO2/Ag sandwich structure film showed a thermo-responsive electrical conductivity and an outstanding bending stability, due to network structure formed by nanowires. It was experimentally proved that this sandwich structure was superior to other layer structures in IR shielding performance and thermo-responsive electrical conductivity. The as-prepared Ag/VO2/Ag sandwich structure film has great potential for various applications such as wearable devices, flexible electronics, medical monitors and smart IR radiation management.

scholarly journals Modeling Mean Radiant Temperature Distribution in Urban Landscapes Using DART

2021 ◽  
Vol 13 (8) ◽  
pp. 1443
Author(s):  
Maria Angela Dissegna ◽  
Tiangang Yin ◽  
Hao Wu ◽  
Nicolas Lauret ◽  
Shanshan Wei ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Thermal Comfort ◽  
Leaf Area ◽  
Remote Sensing Data ◽  
Outdoor Thermal Comfort ◽  
Transfer Model ◽  
Mean Radiant Temperature ◽  
Area Index ◽  
Sensing Data ◽  
Radiant Temperature

The microclimatic conditions of the urban environment influence significantly the thermal comfort of human beings. One of the main human biometeorology parameters of thermal comfort is the Mean Radiant Temperature (Tmrt), which quantifies effective radiative flux reaching a human body. Simulation tools have proven useful to analyze the radiative behavior of an urban space and its impact on the inhabitants. We present a new method to produce detailed modeling of Tmrt spatial distribution using the 3-D Discrete Anisotropic Radiation Transfer model (DART). Our approach is capable to simulate Tmrt at different scales and under a range of parameters including the urban pattern, surface material of ground, walls, roofs, and properties of the vegetation (coverage, shape, spectral signature, Leaf Area Index and Leaf Area Density). The main advantages of our method are found in (1) the fine treatment of radiation in both short-wave and long-wave domains, (2) detailed specification of optical properties of urban surface materials and of vegetation, (3) precise representation of the vegetation component, and (4) capability to assimilate 3-D inputs derived from multisource remote sensing data. We illustrate and provide a first evaluation of the method in Singapore, a tropical city experiencing strong Urban Heat Island effect (UHI) and seeking to enhance the outdoor thermal comfort. The comparison between DART modelled and field estimated Tmrt shows good agreement in our study site under clear-sky condition over a time period from 10:00 to 19:00 (R2 = 0.9697, RMSE = 3.3249). The use of a 3-D radiative transfer model shows promising capability to study urban microclimate and outdoor thermal comfort with increasing landscape details, and to build linkage to remote sensing data. Our methodology has the potential to contribute towards optimizing climate-sensitive urban design when combined with the appropriate tools.

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