rayman model
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Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 99
Author(s):  
Olga Shevchenko ◽  
Sergiy Snizhko ◽  
Sergii Zapototskyi ◽  
Andreas Matzarakis

The human-biometeorological conditions in Ukraine during two mega-heat waves were analyzed. The evaluation is based on physiologically equivalent temperature (PET). The calculation of PET is performed utilizing the RayMan model. The results revealed these two mega-heat waves produced strenuous human-biometeorological conditions on the territory of Ukraine. During the summer 2010 mega-heat wave, strong and extreme heat stress prevailed at about midday at the stations where this atmospheric phenomenon was observed. The mega-heat wave of August 2015 was characterized by a lower heat load. The diurnal variation of PET values during the researched mega-HW was similar to that of the diurnal variation of air temperature with minimum values in the early morning and maximum values in the afternoon. On the territory where mega-heat waves were observed, the number of days during which heat stress occurred for 9 h amounted to 97.6% for the period from 31 July to 12 August 2010 and 77.1% for the mega-heat wave of August 2015.


Author(s):  
Christian A. Njoku ◽  
Ikenna Orisakwe ◽  
Vincent N. Ojeh

The human biometeorological conditions at mid-afternoon during 12 months of 2012 in the city of Minna North-Central Nigeria have been evaluated based on energy budget indices (UTCI and PET) using climate parameters -air temperature, relative humidity, wind speed and solar radiation) observed at 15:00LST as input into the Rayman model. Air temperature demonstrated strongest significant correlation coefficient (r) with UTCI and PET (r= 0.91, r= 0.93) (P<0.0001) while windspeed show weakest association with them(r=-0.10, r=-0.20) (P<0.03, P<0.001) respectively. March and August were characterized by peak and slightest monthly thermal stress conditions according to both indices. The correlation coefficient between both indices was significantly (P<0.0001) very strong (r=0.98) and more noticeable for equivalent temperatures in strong stress thresholds (UTCI>=32°C, PET>=35°C), which shows that both indices can be used indifferently in warm climates. However, during May to October, UTCI better expressed warm conditions than PET mainly due to the difference in the definition of reference environment for both indices; this study is relevant to the urban sightseeing industry as tourists would most likely opt for a period of lesser thermal discomfort.


2021 ◽  
Vol 54/55 (54/55) ◽  
pp. 43-54
Author(s):  
Olga Shevchenko ◽  
Sergiy Snizhko ◽  
Mariia Matviienko

The objective of this research is to assess the bioclimate of the city of Kharkiv in the summer season using the human thermal index of physiologically equivalent temperature (PET). The RayMan model has been used to obtain PET values. The results suggest that most days in Kharkiv during the summer are characterized by heat stress of various intensity 65.7% in June, 84.6% in July, 77.1% in August. The average frequency of comfortable weather is very low, varying from 12.6 to 25%. During heat waves, the frequency of days in Kharkiv with heat stress increases significantly, amounting to 96.3%. The results of the Kharkiv bioclimate assessment using PET may be used to create measures for heat adaptation and develop infrastructure for recreation and tourism in the city during hot periods.


Author(s):  
Jit Biswas

Gangetic West Bengal (GWB) belongs to Aw climate type after Köppen-Geiger climate classification (KGC). Human thermal comfort (HTC) and vapour pressure (VP) conditions together can represent human-biometeorological comfort conditions. Physiological equivalent temperature (PET) is used for indexing HTC. 3-hr PET and VP values are calculated based on hourly meteorological data of six selected cities for 18 years (2000-2017) time period. RayMan model has been applied to calculate hourly PETs and VPs. PET and VP data are grouped by frequencies and time period into several classes. Spatial distribution and dispersion characters of biometeorological comfort conditions are measured by statistical techniques. Thermally heat stress is very high in Apr and May. Months of winter indicate the presence of different thermal conditions. Annual comfort is maximum in the coastal city when stressful condition mostly prevails over Krishnanagar (KNG). Puruliya (PRA) shows the driest condition. The obtained information can be applied in planning, healthcare, and tourism sector.


2019 ◽  
Vol 12 (3) ◽  
pp. 1-33
Author(s):  
Morteza Ojaghlou ◽  
Mehdi Khakzand

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.


Author(s):  
David Alfonso-Solar ◽  
Paula Bastida-Molina ◽  
Lina Montuori ◽  
Carlos Vargas-Salgado

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.


2019 ◽  
Vol 8 (2) ◽  
pp. 95-102
Author(s):  
Melania A. Sumaryata ◽  
Charlie L. B. Afriesta ◽  
Mochamad D. Koerniawan
Keyword(s):  

Kenyamanan termal dalam perancangan kawasan menjadi salah satu yang perlu diperhatikan. Ruang luar merupakan ruang yang perancangannya harus memperhatikan kenyamanan dari segi termal. Kawasan Kampus Institut Teknologi Bandung (ITB) merupakan salah satu kawasan yang memiliki ruang luar dalam menunjang kegiatan civitas akademik, salah satunya adalah koridor ITB. Koridor ITB merupakan salah satu area ruang luar paling aktif di kawasan kampus, hal ini dikarenakan koridor ini merupakan axis utama yang ada di kawasan ini. Tujuan dari penelitian ini adalah untuk mengetahui persepsi dan preferensi kenyamanan termal pada koridor ITB. Metode pengumpulan data dilakukan dengan pengukuran data dan wawancara. Analisis pada penelitian ini menggunakan analisis distribusi dan analisis menggunakan alat pengukuran Rayman model untuk mendapatkan PET, PMV, SET*, dan SVF. Hasil dari penelitian menunjukan bahwa kenyamanan termal dipengaruhi oleh metabolisme tubuh laki-laki dan perempuan, jenis kegiatan yang dilakukan, serta pakaian yang dipakai.


2019 ◽  
Vol 136 ◽  
pp. 05010
Author(s):  
Moyan Zhang ◽  
Yan Liu ◽  
Ruixin Chen ◽  
Xiangfei Guo ◽  
Weiqing Yuan ◽  
...  

In this paper, the total daily global solar radiation is tested at 18 locations with different morphological characteristics in Xi’an University of Architecture and Technology. PTgui is used to convert the panoramic pictures from Baidu Street Map to fisheye images. Sky view factor (SVF) and tree view factor (TVF) are calculated by Rayman model with fisheye images. SVF is used to calculate the total daily global solar radiation at the 18 locations with two different methods and TVF is used to classify the locations. The calculations and testing results are compared and combined the morphological characteristics. Then it is found that using suitable methods on different locations is necessary to obtain more accurate results whether the TVF (tree view factor) is more than 0.3 or less. To obtain solar radiation at different locations in the urban area, the calculating methods should be carefully chosen based on the morphology characteristics of the location.


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