scholarly journals The most problematic variable in the course of human-biometeorological comfort assessment — the mean radiant temperature

2011 ◽  
Vol 3 (1) ◽  
Author(s):  
Noémi Kántor ◽  
János Unger
Keyword(s):  
Thermal Comfort ◽  
Short Wave ◽  
Urban Environments ◽  
Outdoor Thermal Comfort ◽  
Radiation Environment ◽  
Wave Radiation ◽  
Mean Radiant Temperature ◽  
Radiation Fluxes ◽  
The Mean ◽  
Radiant Temperature

AbstractThis paper gives a review on the topic of the mean radiant temperature Tmrt, the most important parameter influencing outdoor thermal comfort during sunny conditions. Tmrt summarizes all short wave and long wave radiation fluxes reaching the human body, which can be very complex (variable in spatial and also in temporal manner) in urban settings. Thermal comfort researchers and urban planners need easy and sound methodological approaches to assess Tmrt. After the basics of the Tmrt calculation some of the methods suitable for obtaining Tmrt also in urban environments will be presented.. Two of the discussed methods are based on instruments which measure the radiation fluxes integral (globe thermometer, pyranometer-pyrgeometer combination), and three of the methods are based on modelling the radiation environment with PC software (RayMan, ENVI-met and SOLWEIG).

Differents Methods to Estimate the Mean Radiant Temperature in an Urban Canyon

2013 ◽  
Vol 650 ◽  
pp. 647-651 ◽  
Author(s):  
R. de Lieto Vollaro ◽  
A. Vallati ◽  
S. Bottillo
Keyword(s):  
Human Body ◽  
Street Canyon ◽  
The Other ◽  
Radiation Environment ◽  
Mean Radiant Temperature ◽  
Radiation Fluxes ◽  
Human Energy ◽  
Environment Simulation ◽  
The Mean ◽  
Radiant Temperature

The mean radiant temperature is one of the meteorological key parameters governing human energy balance and the thermal comfort of human body. This variable can be considered as the sum of all direct and reflected radiation fluxes to which the human body is exposed. After the basics of the Tmrt calculation a comparison between two methods suitable for obtaining Tmrt in a street canyon will be presented. One of the discussed methods of obtaining Tmrt is based on the utilization of a globe thermometer. The other method is the radiation environment simulation through three PC software (RayMan, ENVI-met and SOLWEIG).

scholarly journals Roof-Integrated Green Technologies, Energy Saving and Outdoor Thermal Comfort: Insights from a Case Study in Urban Environment

2021 ◽  
Vol 16 (1) ◽  
pp. 13-23
Author(s):  
Guglielmina Mutani ◽  
Valeria Todeschi
Keyword(s):  
Thermal Comfort ◽  
Energy Saving ◽  
Green Roofs ◽  
Outdoor Thermal Comfort ◽  
Mean Radiant Temperature ◽  
Green Technologies ◽  
Heating And Cooling ◽  
Before And After ◽  
The Mean ◽  
Radiant Temperature

Green urban infrastructures have a significant impact on urban climate mitigation, on indoor and outdoor thermal comfort and on energy performance of buildings. In this paper, outdoor thermal comfort conditions and energy saving for space heating and cooling were investigated before and after the use of roof-integrated green technologies. Existing urban energy and climate models and tools were applied to an urban area located in a Turin (Italy). CitySim, ENVI-met and SOLWEIG tools and a GIS-based model were used to evaluate the mean radiant temperature and the thermal comfort of outdoor spaces before and after the use of vegetated roofs and green surfaces such as the predicted mean vote (PMV), the physiological equivalent temperature (PET) and the universal thermal climate index (UTCI). A GIS-based engineering model and CitySim tool were used to evaluate the energy saving and energy independence index for space heating and cooling after the use of green roofs and solar technologies. According to the shape and the suitability of rooftop elaborated with GIS tools, some roofs were identified as potential green roofs other as potential solar roofs for installing solar thermal collectors and photovoltaic panels. According to the results it is possible to confirm that the use of green roofs and urban greenery can decrease the mean radiant temperature until about 10℃ during summer season, improving outdoor thermal comfort conditions and energy savings with a reduction of 12% for space cooling energy consumption.

scholarly journals Modelling mean radiant temperature in outdoor environments: contrasting the approaches of different simulation tools

2021 ◽  
Vol 2069 (1) ◽  
pp. 012186
Author(s):  
E Badino ◽  
M Ferrara ◽  
L Shtrepi ◽  
E Fabrizio ◽  
A Astolfi ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Outdoor Thermal Comfort ◽  
Mean Radiant Temperature ◽  
Simulation Tools ◽  
Outdoor Spaces ◽  
Outdoor Environments ◽  
The Mean ◽  
Radiant Temperature ◽  
Available Information ◽  
And Control

Abstract Global warming and increasing urbanization are expected to threaten public health in cities, by increasing the heat stress perceived by the inhabitants. Outdoor thermal comfort conditions are influenced by the material and the geometric features of the surrounding urban fabric at both the urban and building scales. In built environments, performance-aware design choices related to street paving or building façade can enhance outdoor thermal comfort in their surroundings. Reliable estimations of outdoor thermal comfort conditions are required to evaluate and control the micro-bioclimatic influences of different design choices. The mean radiant temperature is the physical variable that has the greatest influence on outdoor thermal comfort conditions during summertime. Since its calculation is complex, the available simulation tools employ different approaches and assumptions to estimate it, and potential users need to be aware of their capabilities and simplifications. This research compares the calculation procedures and assumptions of different performance simulation tools (i.e. ENVI-met, TRNSYS, Ladybug/Honeybee, CitySim, and SOLENE-microclimat) to predict the mean radiant temperature in outdoor spaces, based on the available information in the scientific literature. Their ability to account for different radiative components in both the longwave and shortwave spectra is summarized, and practical information regarding the degree of interoperability with the modelling environments and the level of geometrical detail of the virtual model supported by the tools is provided. This work aims to help potential users in the selection of the most appropriate performance tool, based on the requirement of their projects.

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.

scholarly journals Evaluating the Effects of Façade Greening on Human Bioclimate in a Complex Urban Environment

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Britta Jänicke ◽  
Fred Meier ◽  
Marie-Therese Hoelscher ◽  
Dieter Scherer
Keyword(s):  
Heat Stress ◽  
Short Wave ◽  
Wave Radiation ◽  
Short Wave Radiation ◽  
Long Wave ◽  
Building Facades ◽  
Urban Heat ◽  
The Mean ◽  
Human Bioclimate ◽  
Radiant Temperature

The evaluation of the effectiveness of countermeasures for a reduction of urban heat stress, such as façade greening, is challenging due to lacking transferability of results from one location to another. Furthermore, complex variables such as the mean radiant temperature(Tmrt)are necessary to assess outdoor human bioclimate. We observedTmrtin front of a building façade in Berlin, Germany, which is half-greened while the other part is bare.Tmrtwas reduced (mean 2 K) in front of the greened compared to the bare façade. To overcome observational shortcomings, we applied the microscale models ENVI-met, RayMan, and SOLWEIG. We evaluated these models based on observations. Our results show thatTmrt(MD = −1.93 K) and downward short-wave radiation (MD = 14.39 W/m2) were sufficiently simulated in contrast to upward short-wave and long-wave radiation. Finally, we compare the simulated reduction ofTmrtwith the observed one in front of the façade greening, showing that the models were not able to simulate the effects of façade greening with the applied settings. Our results reveal that façade greening contributes only slightly to a reduction of heat stress in front of building façades.

scholarly journals Thermal comfort of patients in hospital ward areas

1977 ◽  
Vol 78 (1) ◽  
pp. 17-26 ◽  
Author(s):  
R. M. Smith ◽  
A. Rae
Keyword(s):  
Steady State ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Hospital Ward ◽  
Patient Comfort ◽  
Mean Radiant Temperature ◽  
Air Velocity ◽  
Assessment Techniques ◽  
The Mean ◽  
Radiant Temperature

SUMMARYThe patient is identified as being of prime importance for comfort standards in hospital ward areas, other ward users being expected to adjust their dress to suit the conditions necessary for patient comfort. A study to identify the optimum steady state conditions for patient comfort is then described.Although this study raises some doubts as to the applicability of the standard thermal comfort assessment techniques to ward areas, it is felt that its results give a good indication of the steady-state conditions preferred by the patients. These were an air temperature of between 21.5° and 22° C and a relative humidity of between 30% and 70%, where the air velocity was less than 0.1 m/s and the mean radiant temperature was close to air temperature.

scholarly journals PAIR INFLUENCE OF WIND SPEED AND MEAN RADIANT TEMPERATURE ON OUTDOOR THERMAL COMFORT OF HUMID TROPICAL ENVIRONMENT

2017 ◽  
Vol 10 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Sangkertadi Sangkertadi ◽  
Reny Syafriny
Keyword(s):  
Wind Speed ◽  
Thermal Comfort ◽  
Significant Role ◽  
Tropical Environment ◽  
Outdoor Thermal Comfort ◽  
Regression Equations ◽  
Mean Radiant Temperature ◽  
Walking Activity ◽  
Globe Temperature ◽  
Radiant Temperature

The purposes of this article is to explore knowledge of outdoor thermal comfort in humid tropical environment for urban activities especially for people in walking activity, and those who stationary/seated with moderate action. It will be characterized the pair influence of wind speed and radiant temperature on the outdoor thermal comfort. Many of researchers stated that those two microclimate variables give significant role on outdoor thermal comfort in tropical humid area. Outdoor Tropical Comfort (OTC) model was used for simulation in this study. The model output is comfort scale that refers on ASHRAE definition. The model consists of two regression equations with variables of air temperature, globe temperature, wind speed, humidity and body posture, for two types of activity: walking and seated. From the results it can be stated that there is significant role of wind speed to reduce mean radiant temperature and globe temperature, when the velocity is elevated from 0.5 m/s to 2 m/s. However, the wind has not play significant role when the speed is changed from 2 m/s to 3.5 m/s. The results of the study may inspire us to implement effectiveness of electrical-fan equipment for outdoor space in order to get optimum wind speed, coupled with optimum design of shading devices to minimize radiant temperature for thermal comfort.

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