Assessing the accuracy of globe thermometer method in predicting outdoor mean radiant temperature under Malaysia tropical microclimate

Khrit, N. G.; Alghoul, M. A.; Sopian, Kamaruzzaman; Lahimer, A. A.; Elayeb, Omkalthum

doi:10.1051/e3sconf/20172301006

Cited by 7 publications

(3 citation statements)

References 14 publications

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“…It has been estimated by the formulation proposed in ISO 7726:1998 [49]. Different researchers employ the same solution to solve the mean radiant temperature [48,[50][51][52][53]. On the other hand, according to the Q value, a 5-point scale was defined for assessing people's sensations, as resumed in Table 5.…”

Section: Thermal Comfort Indexmentioning

confidence: 99%

Thermal Resilience of Citizens: Comparison between Thermal Sensation and Objective Estimation in Outdoor Spaces: A Case Study in Seville, Spain

et al. 2022

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Sanitary issues, combined with the effects of climate change, emphasize the comfort of outdoor spaces in cities. Numerous comfort models exist and can predict thermal sensation. However, these comfort indices need to be validated in hot zones and quantify the neutral range considering people’s thermal resilience. The present study investigates the outdoor thermal comfort of people who live in hot areas and are accustomed to this and quantifies this effect. For that, predictions provided by the COMFA thermal comfort model were compared with the occupants’ perceptions given in the field campaigns’ questionnaires. The field campaigns were associated with on-site monitoring of local climate variables. It was observed that during the survey period, the entire space was predicted to be uncomfortable by the COMFA model. On the contrary, the results of the questionnaires showed that the most frequently encountered thermal sensations were distributed between the comfort zone and the hot zone. The proposed methodology has been designed to be used by other researchers, and it is adaptable to other outdoor thermal comforts such as PET or ITS. The comparison between the model’s predictions and the users’ responses to space highlighted the tendency of the COMFA to overestimate the thermal sensations. This work’s results allow extending the neutral comfort band from 50 W/m2 (value of literature) to 80 W/m2. So, the paper quantifies that the effect of the thermal resilience of the people increases the thermal band of comfort by around 60%. These results will allow an accurate assessment of the effectiveness of future mitigation solutions implemented to improve outdoor thermal comfort in other world areas. It is due to the propose of a higher neutrality range researchers or designers could achieve outdoor thermal comfort in effective and reliable ways, even in hot climates.

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Section: Thermal Comfort Indexmentioning

confidence: 99%

Thermal Resilience of Citizens: Comparison between Thermal Sensation and Objective Estimation in Outdoor Spaces: A Case Study in Seville, Spain

et al. 2022

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“…Both Exp Gravel and Exp Asphalt produced very strong heat stress during daytime hours. The very small distinction between these two surfaces is likely due to the increased sensitivity of the black globe thermometer to direct solar radiation, especially in the middle of the day (Khrit et al 2017), and this could account for the low effect due to reflected solar radiation by different surfaces. A pedestrian in the unshaded gravel and asphalt area would experience a degree of heat stress for the full daytime period.…”

Section: Exp Gravelmentioning

confidence: 99%

UTCI field measurements in an urban park in Florence (Italy)

Petralli

Massetti

Pearlmutter

et al. 2020

Miscellanea Geographica

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The aim of this study is to evaluate human thermal comfort in different green area settings in the city of Florence by using the Universal Thermal Climate Index (UTCI). Field measurements of air temperature, solar radiation, relative humidity, wind speed and black globe thermometer were collected during hot summer days in various parts of Cascine Park, the biggest urban park in Florence (Italy). UTCI was evaluated over different surfaces (asphalt, gravel and grass) completely exposed to the sun or shaded by a large lime tree (Tilia × europaea). The results showed strong differences in UTCI values depending on the exposure to tree shade, while no significant difference was found among ground-cover materials when all surfaces were equally exposed to solar radiation. Future studies are needed to investigate the microclimatic effects of different tree species on UTCI.

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“…On the other hand, some researchers have researched the structure of the black bulb thermometer, aiming at improving the response time of the black bulb thermometer to improve the accuracy of calculating the mean radiation temperature. Khrit [19] conducted experiments in Malaysia by using two copper hollow spheres with diameters of 50 and 150 mm. Compared with the six-direction radiation method, we see that that the results of the black bulb thermometer with a smaller diameter respond faster, but the results fluctuate more when the radiation and wind speed change rapidly.…”

Section: Introductionmentioning

confidence: 99%

Study on the Influence of Globe Thermometer Method on the Accuracy of Calculating Outdoor Mean Radiant Temperature and Thermal Comfort

et al. 2022

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With global warming and the rapid development of urbanization, the outdoor thermal environment is deteriorating. More and more research focuses on the outdoor thermal environment and thermal comfort. The globe thermometer method is widely used in more than half of the outdoor thermal environment research studies, but there is a large error compared with the six-direction method. In order to explore the accuracy of the results of the globe thermometer method and its impact on the subsequent thermal comfort indicators, this study carried out a year-round comparative experiment under multiple working conditions outdoors in cold areas to explore the impact of meteorological parameters such as shortwave radiation, wind speed, and wind direction on the results of the globe thermometer method. The results show that the continuous increase of shortwave radiation reduces the accuracy of the black bulb thermometer to less than 60%, and the instantaneous change of wind speed will make the deviation of the mean radiation temperature obtained by the globe thermometer method exceed 5 °C. The influence of the mean radiation temperature obtained by the globe thermometer method on the thermal comfort index is mainly reflected in the working condition of a high temperature and strong radiation in summer. Taking the six-direction method as the standard, this study gives the scope of application of the globe thermometer method; and taking the human body calculation model of PET as an example, a universal optimization method for detailed division of radiation heat transfer calculation is proposed, so that it can get more accurate and rigorous conclusions in the evaluation of outdoor complex radiation environment.

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Assessing the accuracy of globe thermometer method in predicting outdoor mean radiant temperature under Malaysia tropical microclimate

Cited by 7 publications

References 14 publications

Thermal Resilience of Citizens: Comparison between Thermal Sensation and Objective Estimation in Outdoor Spaces: A Case Study in Seville, Spain

Thermal Resilience of Citizens: Comparison between Thermal Sensation and Objective Estimation in Outdoor Spaces: A Case Study in Seville, Spain

UTCI field measurements in an urban park in Florence (Italy)

Study on the Influence of Globe Thermometer Method on the Accuracy of Calculating Outdoor Mean Radiant Temperature and Thermal Comfort

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