An experimental technique based on globe thermometers for the measurement of mean radiant temperature in urban settings

Banfi, Alessia; Tatti, Anita; Ferrando, Martina; Fustinoni, Damiano; Zanghirella, Fabio; Causone, Francesco

doi:10.1016/j.buildenv.2022.109373

Cited by 9 publications

(10 citation statements)

References 26 publications

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“…Moreover, according to Humphrey [53], a 40 mm globe painted gray better approximates the mean radiant temperature than a standard 15 cm black globe indoors. This statement was also validated in outdoor conditions in [54,55]. Both cited studies undertook a local calibration to determine the relation between the mean radiant temperature and the globe temperature for their subtropical climates.…”

Section: Mean Radiant Temperature Via Globe Temperaturementioning

confidence: 90%

Advancing Urban Microclimate Monitoring: The Development of an Environmental Data Measurement Station Using a Low-Tech Approach

Lefevre,

Malet-Damour,

Boyer

et al. 2024

Sustainability

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Researchers studying urban climates aim to understand phenomena like urban heat islands (UHIs), which describe temperature differences between urban and rural areas. However, studies often lack numerous measurement points and frequently overlook parameters like radiation and air velocity due to the high cost of precision instrumentation. This results in data with a low resolution, particularly in tropical cities where official weather stations are scarce. This research introduces a new, low-tech tool for district-level outdoor thermal comfort assessment and UHI characterization to address these challenges. The automated weather station employs sensors to measure temperature, humidity, wind speed, solar radiation, and globe temperature. The paper details these sensors’ rigorous selection and validation process, followed by a description of the sensor assembly, data acquisition chain, and network operation mechanisms. Calibration outcomes in laboratory and in situ environments highlight the station’s reliability, even in tropical conditions. In conclusion, this weather station offers a cost-effective solution to gathering high-resolution data in urban areas, enabling an improved understanding of the UHI phenomenon and the refinement of urban microclimate numerical models.

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Section: Mean Radiant Temperature Via Globe Temperaturementioning

confidence: 90%

Advancing Urban Microclimate Monitoring: The Development of an Environmental Data Measurement Station Using a Low-Tech Approach

Lefevre,

Malet-Damour,

Boyer

et al. 2024

Sustainability

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“…Szczególnie trudne jest dokładne określenie ilości energii pochłoniętej przez człowieka, co wynika ze skomplikowanej budowy ciała ludzkiego oraz złożonych interakcji między poszczególnymi strumieniami promieniowania krótko-i długofalowego (Kenny et al, 2008). Co więcej, w środowisku zewnętrznym analiza pola promieniowania jest dodatkowo utrudniona przez dynamicznie zmieniające się warunki solarne oraz obecność wielu zróżnicowanych powierzchni, które mogą w różny sposób absorbować, emitować lub odbijać promieniowanie słoneczne (Banfi et al, 2022). Dlatego też w badaniach komfortu cieplnego stosuje się pewne uproszczenia i jako miarę termicznego wymiaru pola promieniowania wokół człowieka, najczęściej wykorzystuje się koncepcję średniej temperatury promieniowania (Mrt -Mean radiant temperature).…”

Section: Wstępunclassified

“…• sferyczny kształt tego przyrządu uśrednia pochłonięte promieniowanie jednakowo ze wszystkich kierunków, co daje dobre oszacowanie Mrt dla człowieka w pozycji siedzącej, ale nie dla osoby stojącej czy maszerującej (gdyż w tej pozycji przeważa dopływ bocznych strumieni promieniowania) (Thorsson et al, 2007;Kántor i Unger, 2011); • standardowe termometry kuliste posiadające czarną powłokę mają tendencję do przeszacowywania absorbcji promieniowania krótkofalowego w stosunku do rzeczywistej ilości pochłoniętej przez skórę i odzież (Johansson et al, 2014;Banfi et al, 2022;Tang i Li, 2022);…”

Section: Wstępunclassified

“…Sugeruje się stosowanie sfer pomalowanych na jasnoszary kolor, o wyższym albedo (International Organization for Standardization, 1998;Johansson et al, 2014). Dotychczas modyfikację tę zastosowano już z powodzeniem w wielu badaniach, stosując najczęściej kolor RAL 7001, jednak w warunkach intensywnego dopływu promieniowania słonecznego wartości Mrt wyznaczone takim instrumentem mogą być zaniżone (Thorsson et al, 2007;Vanos et al, 2021;Banfi et al, 2022).…”

Section: Wstępunclassified

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Niepewność pomiarów średniej temperatury promieniowania za pomocą termometrów kulistych = Uncertainty of mean radiant-temperature measurements using globe thermometers

Lindner-Cendrowska,

Baranowski

2023

Prz. Geogr.

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In the analysis of the human heat balance, the biggest problem is to precisely determine the amount of energy absorbed by a human organism under dynamically changing solar conditions and while being surrounded by many different surfaces that can absorb, emit or reflect solar radiation in different ways. Therefore, in thermal comfort studies some simplifications of the radiation field around human body are necessary and thus the concept of mean radiant temperature (Mrt) is most often used. Mrt values can be derived either from direct instrumental measurements or calculated by one of the microclimate models. The most accurate way to determine the Tmrt outdoors is by integral radiation measurements and the calculation of angular factors (i.e. the proportion of radiation received by the human body from different directions). This method involves simultaneous measurements of long- and short-wave radiation flux densities in six directions, which requires three sets of net radiometers. Although this method of Mrt determination describes the radiation environment accurately and independently of the variable wind field, it requires the use of expensive and complex measurement devices. Cheap and easy to operate alternative offers globe thermometer. In steady state conditions, readings from the air temperature sensor inside the globe thermometer (tg) will reflect the convective and radiative heat exchange around the globe thermometer. Knowing tg, as well as globe emissivity and diameter, the Mrt may be calculated. In this research three different globe thermometers were used to determine Mrt: 15-cm standard globe thermometer (SGT) and two 4-cm custom made acrylic globe thermometers (AGT) painted in black and grey. The measurements were conducted in the summer in Warsaw, on two selected green areas, under sunny and warm weather conditions. In each location Mrt measurements were taken in two spots – in the shade of trees and in the open grassy spaces, with high SVF. Our results demonstrate, that globe thermometers, although being relatively cheap and less complex instruments for determining Mrt, can be used to a limited extend, due to high instability of their indications under significant radiative loads.

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“…A temperature sensor is placed in the center of a hollow sphere to form a globe thermometer, which was invented by Vernon in 1932 and designed for indoor use [12]. Additionally, globe thermometers have recently been used in outdoor settings as they can be a straightforward and less expensive alternative to net radiometers [16]. Globe temperature is therefore influenced by the values of air temperature, wind speed, and short and long-wave radiant fluxes.…”

Section: Introductionmentioning

confidence: 99%

An Investigation on Globe Temperature in Street Canyon: A Scaled Model Study Implementing Cool Materials

Zingre

2024

Preprint

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Measurement of Globe temperature is essential for investigating thermal comfort in street canyon. Globe thermometer is the most common instrument used to measure globe temperature (GT), however its application in scale models is still uncertain and not thoroughly investigated as of today. Therefore, this study is explicitly conducted to investigate globe thermometer measurements and proposed an improvised customization of the globe thermometer size to enhance reliability in scale models. The experiments were carried out outdoors using a typical street canyon model (scale 1:100) with East-West street orientation. The experiment presented a comparison between a low solar reflective street canyon (albedo of 0.4) and a high solar reflective canyon (albedo of 0.6) in terms of surface temperatures, heat flux and globe temperature. Furthermore, this study also investigated the influence of solar orientation on the globe temperature using both experimental using scale models and microclimatic modelling using ENVI-met. It is observed that although the surface temperatures are lower with high solar reflective canyon compared to that with low solar reflective canyon, GT is higher in high reflective canyon during daytime, which could be due to combined effect of direct radiation and shortwave reflection. However, for hours after the sun set, GT becomes lower (up to 1°C) in the case of high reflective canyon compared to low reflective canyon.

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An experimental technique based on globe thermometers for the measurement of mean radiant temperature in urban settings

Cited by 9 publications

References 26 publications

Advancing Urban Microclimate Monitoring: The Development of an Environmental Data Measurement Station Using a Low-Tech Approach

Advancing Urban Microclimate Monitoring: The Development of an Environmental Data Measurement Station Using a Low-Tech Approach

Niepewność pomiarów średniej temperatury promieniowania za pomocą termometrów kulistych = Uncertainty of mean radiant-temperature measurements using globe thermometers

An Investigation on Globe Temperature in Street Canyon: A Scaled Model Study Implementing Cool Materials

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