scholarly journals Thermal Comfort Characteristic of 5 Patterns of a Persian Garden in a Hot-Arid Climate of Shiraz, Iran

2019 ◽  
Vol 12 (3) ◽  
pp. 1-33
Author(s):  
Morteza Ojaghlou ◽  
Mehdi Khakzand
Keyword(s):  
Thermal Comfort ◽  
Fossil Fuels ◽  
Shortwave Radiation ◽  
View Factor ◽  
Physiological Equivalent Temperature ◽  
Hot Climate ◽  
Hot Arid Climate ◽  
Urban Heat ◽  
Radiant Temperature ◽  
Rayman Model

Abstract Thermal comfort in the open spaces is a significant parameter in public mentally and physically healthy. Increased hot days of cities because of the urban heat island is the common phenomenon in cities. This phenomenon effect cites quality by a different aspect such as air quality, Use of fossil fuels etc. therefore, cooling strategies in the urban and urban park’s design is one of the important issues of the designers. Urban parks have a significant effect on heat stress mitigation. Persian garden is known for its microclimate effect on pedestrians, so different patterns of Persian garden is selected to be analyzed in terms of thermal comfort condition on the hottest day of summer so far in the dry hot climate of the Shiraz(12th of July 1998 with the maximum 42°C Ta). In this paper 8 conditions are simulated by Envi-met3.1 to get environment data of these patterns and also the Rayman model is used to calculate the Physiological Equivalent Temperature (PET) as the proper thermal index for outdoor condition. The results demonstrate that alteration of Shortwave radiation both direct and diffuse conditions and mean radiant temperature are affected by both sky view factor and the orientation of the Persian garden. Pavilion location has an important effect in mitigation of the Tmrt by preventing the afternoon powerful sun rays through to the paths in the End.E-W pattern. Therefore, this pattern has a better condition of PET value than the others in Shiraz setting.

scholarly journals Biomimicry-Based Strategies for Urban Heat Island Mitigation: A Numerical Case Study under Tropical Climate

Biomimetics ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 48
Author(s):  
Kevin Araque ◽  
Paola Palacios ◽  
Dafni Mora ◽  
Miguel Chen Austin
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Urban Areas ◽  
Outdoor Thermal Comfort ◽  
Base Case ◽  
Heat Island ◽  
Urban Heat ◽  
Historical Heritage ◽  
Pet Index ◽  
Radiant Temperature

In recent years, demographic growth has caused cities to expand their urban areas, increasing the risk of overheating, creating insurmountable microclimatic conditions within the urban area, which is why studies have been carried out on the urban heat island effect (UHI) and its mitigation. Therefore, this research aims to evaluate the cooling potential in the application of strategies based on biomimicry for the microclimate in a historical heritage city of Panama. For this, three case studies (base case, case 1, and case 2) of outdoor thermal comfort were evaluated, in which the Envi-met software was used to emulate and evaluate the thermal performance of these strategies during March (highest temperature month) and October (rainier month). The strategies used were extracted from the contrast of zebra skin, human skin, evaporative cooling, and ant skin. The results showed a reduction of 2.8 °C in the air temperature at 11:00, the radiant temperature decreased by 2.2 °C, and the PET index managed to reduce the thermal comfort indicator among its categories. The importance of thinking based on biomimicry in sustainable strategies is concluded; although significant changes were obtained, high risks of discomfort persist due to the layout and proximity of the building.

scholarly journals The Evaluation of Outdoor Thermal Sensation and Outdoor Energy Efficiency of a Commercial Pedestrianized Zone

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1324 ◽  
Author(s):  
Xuan Ma ◽  
Hiroatsu Fukuda ◽  
Dian Zhou ◽  
Mengying Wang
Keyword(s):  
Energy Efficiency ◽  
Thermal Comfort ◽  
Open Space ◽  
Thermal Sensation ◽  
Heat Island ◽  
Physiological Equivalent Temperature ◽  
Winter Climate ◽  
Coverage Ratio ◽  
Urban Heat ◽  
The Relationship

The growth of the scale of cities intensifies urban heat island (UHI) by obstructing the wind and building more radiation at pedestrian level, thus leading to an energy consumption. Commercial pedestrianized-zones cannot only become symbols of cities but also an important factor increasing local economic income. This study conducts on-site measurement and numerical simulation to evaluate the cooling energy efficiency of different parameters (building, vegetation, pavement material) in Fo Shan city, which locates in hot-summer and warm-winter climate region of China. Also, calculations are done to evaluate the index physiological equivalent temperature (PET) for understanding thermal sensation at a pedestrian level (1.5 m). To evaluate different impacts of this zone renewal on the environment and choose the most energy-saving method, it is easy for us to utilize the linear regression for understanding the relationship between coverage ratio of trees (TCR) and thermal comfort in canyon space, which shows that ∆PET = 0.1703 × TCR + 0.2444 with a most important R2 value of 0.9836, for TCR increases from 12.5% to 22%. In open space, also increasing coverage ratio of trees (TCR) can effectively improve humans’ thermal comfort, which shows that ∆PET = 0.2644 × TCR + 0.3955 with a most important R2 value of 0.8892.

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 Bioclimatic Architecture and Urban Morphology. Studies on Intermediate Urban Open Spaces

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5819
Author(s):  
Alessandra Battisti
Keyword(s):  
Thermal Comfort ◽  
Urban Heat Island ◽  
Well Being ◽  
Urban Morphology ◽  
Urban Heat Island Effect ◽  
Heat Island ◽  
Open Spaces ◽  
Physiological Equivalent Temperature ◽  
Island Effect ◽  
Urban Heat

This paper deals with the interactions between biophysical and microclimatic factors on the one hand with, on the other, the urban morphology of intermediate urban open spaces, the relationship between environmental and bioclimatic thermal comfort, and the implementation of innovative materials and the use of greenery, aimed at the users’ well-being. In particular, the thermal comfort of the open spaces of the consolidated fabrics of the city of Rome is studied, by carrying out simulations of cooling strategies relating to two scenarios applied to Piazza Bainsizza. The first scenario involves the use of cool materials for roofs, cladding surfaces, and pavement, while the second scenario, in addition to the cool materials employed in the first scenario, also includes the use of greenery and permeable green surfaces. The research was performed using summer and winter microclimatic simulations of the CFD (ENVI-met v. 3.1) type, in order to determine the different influences of the materials with cold colors, trees, and vegetated surfaces on the thermal comfort of the urban morphology itself. Meanwhile, the comfort assessment was determined through the physiological equivalent temperature (PET) calculated with the RayMan program. The first scenario, with the use of cool materials, improves summer conditions and reduces the urban heat island effect but does not eliminate thermal discomfort due to the lack of shaded surfaces and vegetation. The second scenario, where material renovations is matched with vegetation improvements, has a slightly bad effect on winter conditions but drastically ameliorates the summer situation, both for direct users and, thanks to the strong reduction of the urban heat island effect, to urban inhabitants as a whole.

scholarly journals Urban heat resilience at the time of global warming: evaluating the impact of the urban parks on outdoor thermal comfort

2020 ◽  
Author(s):  
Farshid Aram ◽  
Ebrahim Solgi ◽  
Ester Higueras García ◽  
Amir Mosavi
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Mental Image ◽  
Urban Parks ◽  
Cooling Effect ◽  
Outdoor Thermal Comfort ◽  
Heat Island ◽  
Physiological Equivalent Temperature ◽  
Urban Heat ◽  
The Impact

Abstract Background: In densely populated urban centers, increased air temperature due to urban heat island (UHI) effect can undermine the thermal comfort and health of citizens. Research has shown that large urban parks can mitigate the effect of UHIs and improve thermal comfort, especially in the warmer months of the year when temperature changes are more noticeable. This study investigated the cooling effect intensity (CEI) of the Retiro Park in the center of Madrid at three different distances from its southern edge and the impact of this cooling effect on thermal comfort from physiological and psychological perspectives. This investigation was performed by measuring microclimate data and conducting a survey simultaneously during the summer days. Results: The results showed that the CEI of the park varies with distance from its edge. Because of this effect, air temperature within the 130m and 280m distance of the park was respectively 1.6°C and 0.9°C lower than the temperature at the 520m distance (the nearest heat island). After examining the effect of the park in terms of Physiological Equivalent Temperature (PET), it was found that the PET at the 130m and 280m distance of the park was 9.3% and 5.4% less than the PET in the heat island domain. More than 81% of the respondents (in all three areas) had a mental image of the park as the place where they would experience the highest level of outdoor thermal comfort, and this rate was higher in the areas closer to the park. The analysis of citizens’ responses about perceived thermal comfort (PTC) showed that citizens in areas with higher CEI had perceived a higher degree of thermal comfort from the psychological perspective.Conclusion: This study demonstrates the significant role of large urban parks located in the core of the populated cities in providing thermal comfort for citizens from both physiological and psychological perspectives. Additionally, the results of this study demonstrated that among the environmental (natural and artificial) factors around the park (topography, urban structure, etc.), the aspect ratio has the greatest impact on thermal comfort.

scholarly journals How Parks Provide Thermal Comfort Perception in the Metropolitan Cores; A Case Study in Madrid Mediterranean Climatic Zone

2020 ◽  
Author(s):  
Farshid Aram ◽  
Ebrahim Solgi ◽  
Sepideh Baghaee ◽  
Ester Higueras García ◽  
Amir Mosavi ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Field Measurements ◽  
Urban Heat Islands ◽  
Cooling Effect ◽  
P Value ◽  
Physical And Mental Health ◽  
Physiological Equivalent Temperature ◽  
Urban Green Spaces ◽  
Urban Heat

The combined effects of global warming and increasing urban heat islands (UHIs) on air temperature and heat stress in cities are notable physical and mental health implications for citizens. With research having shown the effective role of urban green spaces in decreasing urban heat, this study investigated the cooling effect of a large urban park on thermal comfort outside the park area, from psychological and physiological perspectives. The studied park is located in the center of Madrid and adjacent to UHI. The study was performed by conducting field measurements and a survey with questionnaires. The measurements made on six summer days (with two-week intervals) showed that the park&rsquo;s cooling effect could decrease the air temperature by 2.4-2.8&deg;C right up to the edge of the heat island (600m), and decrease the physiological equivalent temperature (PET) by about 3.9&deg;C. By decreasing air temperature and PET, this park was also shown to increase the perceived thermal comfort (PTC) of the citizens from the psychological perspective in the defined area of effect. This perceived thermal comfort was found to have a significant inverse relationship with PET (P-value &lt;0.05). The examination of cognitive maps drawn by citizens showed that out of the 145 respondents, 68.3% marked the park as the area that they perceive as having the greatest thermal comfort, and prefer as the place to spend time enjoying thermal comfort, irrespective of its distance from their location.

scholarly journals Field Assessment of Neighboring Building and Tree Shading Effects on the 3D Radiant Environment and Human Thermal Comfort in Summer within Urban Settlements in Northeast China

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Jing Du ◽  
Lin Liu ◽  
Xin Chen ◽  
Jing Liu
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Short Wave ◽  
Radiant Flux ◽  
View Factor ◽  
Mean Radiant Temperature ◽  
Human Thermal Comfort ◽  
Long Wave ◽  
Shading Effects ◽  
Radiant Temperature

Shading is one of the most effective strategies to mitigate urban local-scale heat stress during summer. Therefore, this study investigates the effects of shading caused by buildings and trees via exhaustive field measurement research on urban outdoor 3D radiant environment and human thermal comfort. We analyzed the characteristics of micrometeorology and human thermal comfort at shaded areas, and compared the difference between building and tree shading effects as well as that between shaded and sunlit sites. The results demonstrate that mean radiant temperature Tmrt (mean reduction values of 28.1°C for tree shading and 28.8°C for building shading) decreased considerably more than air temperature Ta (mean reduction values of 1.9°C for tree shading and 1.2°C for building shading) owing to shading; furthermore, the reduction effect of shading on UTCI synthesized the variation in the above two parameters. Within the shaded areas, short-wave radiant components (mean standardized values of 0.104 for tree shading and 0.087 for building shading) decreased considerably more than long-wave radiant components (mean standardized values of 0.848 for tree shading and 0.851 for building shading) owing to shading; the proportion of long-wave radiant flux densities absorbed by the reference standing person was high, leading to a relatively high long-wave mean radiant temperature, and R2 between long-wave mean radiant temperature and air temperature exceeded 0.8. Moreover, the directional sky view factor (SVF) was utilized in this study, and it showed significant positive correlation with short-wave radiant flux densities, but no statistically evident correlation with long-wave radiant flux densities. Meanwhile, Tmrt was most relevant with SVFS⟶ with R2 of 0.9756. Furthermore, UTCI rose two categories at the sunlit areas compared with that at the shaded areas. In contrast, Ta and Tmrt played the first positive role in UTCI at shaded and sunlit areas, respectively.

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 &deg;C warmer than other orientations. In summer, streets with intercardinal orientations (i.e., northeast-southwest and northwest-southeast) provided the lowest PET (about 2 &deg;C cooler than other orientations) and better thermal comfort

scholarly journals The Impacts of Morphology of Traditional Alleys on Thermal comfort: A case study of Da Long Wang Xiang in Zhenjiang, China

2021 ◽  
Vol 283 ◽  
pp. 02045
Author(s):  
Cen Chen ◽  
Lu Ding ◽  
Yuhan Zhang ◽  
Hainan Qiu ◽  
Yingnan Li
Keyword(s):  
Thermal Comfort ◽  
Rational Design ◽  
Physical Space ◽  
Width Ratio ◽  
View Factor ◽  
Physiological Equivalent Temperature ◽  
Historical District ◽  
New Strategy ◽  
Shading Device

Traditional alleys in China are mostly characterized by dense population, poor infrastructure, and narrow streets. The general renewal approaches of traditional alleys paid more attention to the physical space while they lack consideration for the thermal comfort of residents, which often results in declines in the rational design of the space and vitality of the community. This research takes Da Long Wang Xiang historical district in Zhenjiang as a case study to investigate the relationship between the morphology of street spaces (Alley Width (W), Sky View Factor (SVF), Height to Width Ratio (H/W), building height on both sides of alley) and microclimatic parameters, such as Potential Air Temperature (Ta), Relative Humidity (RH), Wind Speed (WS), Mean Radiation Temperature (Tmrt) and Physiological Equivalent Temperature (PET). The results have shown that: 1) the peak temperature was found at 14:00, and the thermal comfort of all alleys is overheated during this period, particularly NW-SE alleys are hotter than NESW alleys; 2) the deviation of Ta, RH, WS, and Tmrt among the NW-SE alleys during 13:00 to 15:00 are smaller than those among the NE-SW alleys; and 3) set a shading device or higher buildings on the side of the afternoon solar incidence can help to create a more comfortable thermal comfort. The findings of this research will provide a new strategy for the renewal design of traditional alleys.

scholarly journals Monitoring and evaluation of thermal comfort in urban areas: application to Valencia city

2019 ◽  
Author(s):  
David Alfonso-Solar ◽  
Paula Bastida-Molina ◽  
Lina Montuori ◽  
Carlos Vargas-Salgado
Keyword(s):  
Thermal Comfort ◽  
Urban Areas ◽  
Low Cost ◽  
Monitoring And Evaluation ◽  
Temperature Data ◽  
Ambient Conditions ◽  
Physiological Equivalent Temperature ◽  
Globe Temperature ◽  
Rayman Model ◽  
Black Globe Temperature

In this paper, it is presented preliminary results of a methodology for thermal comfort monitoring and evaluation in urban areas based on local metering of ambient conditions and Rayman model application. In the framework of GROWGREEN European project it was installed six monitoring stations for data acquisition of air temperature, relative humidity, wind speed, solar radiation and black globe temperature. Data of first 5 months of monitoring and modelling of one location with Rayman model to calculate  PET (physiological equivalent temperature) is presented. Based on PET it was calculated the percentage of hours with thermal comfort per month, and it was made a comparison between PET and black globe temperature (GT) in order to evaluate the suitability of GT as a single, low cost and robust indicator of thermal comfort in urban areas.

Sign in / Sign up

Export Citation Format

Share Document