A new method for measuring mean radiant temperatures in indoor spaces

A new method for measuring mean radiant temperatures in indoor spaces

WoS Article

The mean radiant temperature is a crucial parameter for assessing human thermal comfort in indoor and outdoor spaces. The black globe thermometer represents the most commonly used device to measure the mean radiant temperature. This paper presents a new method that solves the main problems of black globe thermometers. It removes the dependence on convective phenomena and the emissivity of the globe, which are two main sources of inaccuracies with black globe thermometers. The method is applicable to spaces that are in stationary thermal state, i.e. all room temperatures and air temperature are time independent at least within the period of measurement. The method represents a direct experimental procedure without the necessity of using any auxiliary formula, which is necessary when measuring with black globe thermometers. The method is based on doubletemperature measurements realized by contact and non-contact thermometers. This study brought new insight into the measurement of the mean radiant temperature. While black globe thermometers prefer highly absorptive coverings that maximize absorption and minimize reflection of radiant heat, white reflective thermometers are based on a fully opposite technical concept utilizing highly reflective coverings that minimize absorption and maximize reflection of heat. The main output of this study consists in presenting the new physical concept amended by the experimental verification based on a series of measurements in both isothermal and nonisothermal indoor spaces. The resulting mean radiant temperatures were obtained with an acceptable accuracy not exceeding 0.7 degrees C that may still be reduced by using highly accurate measuring electronic devices. The method has the potential to account for the thermal anisotropy of spaces and seems to be affordable for a wide group of practitioners who are testing the heat comfort of spaces.

The mean radiant temperature is a crucial parameter for assessing human thermal comfort in indoor and outdoor spaces. The black globe thermometer represents the most commonly used device to measure the mean radiant temperature. This paper presents a new method that solves the main problems of black globe thermometers. It removes the dependence on convective phenomena and the emissivity of the globe, which are two main sources of inaccuracies with black globe thermometers. The method is applicable to spaces that are in stationary thermal state, i.e. all room temperatures and air temperature are time independent at least within the period of measurement. The method represents a direct experimental procedure without the necessity of using any auxiliary formula, which is necessary when measuring with black globe thermometers. The method is based on doubletemperature measurements realized by contact and non-contact thermometers. This study brought new insight into the measurement of the mean radiant temperature. While black globe thermometers prefer highly absorptive coverings that maximize absorption and minimize reflection of radiant heat, white reflective thermometers are based on a fully opposite technical concept utilizing highly reflective coverings that minimize absorption and maximize reflection of heat. The main output of this study consists in presenting the new physical concept amended by the experimental verification based on a series of measurements in both isothermal and nonisothermal indoor spaces. The resulting mean radiant temperatures were obtained with an acceptable accuracy not exceeding 0.7 degrees C that may still be reduced by using highly accurate measuring electronic devices. The method has the potential to account for the thermal anisotropy of spaces and seems to be affordable for a wide group of practitioners who are testing the heat comfort of spaces.

Thermal comfort; Mean radiant temperature; Thermal critical point; Dynamic method; Algebraic radiosity concept.

Thermal comfort; Mean radiant temperature; Thermal critical point; Dynamic method; Algebraic radiosity concept.

FICKER, T.

15.12.2025

APPLIED THERMAL ENGINEERING

281

3

United Kingdom of Great Britain and Northern Ireland

1

24

24

https://www.webofscience.com/wos/woscc/full-record/WOS:001607184600004