Determination of convective and radiative heat transfer coefficients using 34-zones thermal manikin: Uncertainty and reproducibility evaluation

• Convective & radiative heat transfer coefficients were determined across 34 zones.
• Sitting and standing postures were examined repeatedly (3×) using a nude manikin.
• Data were statistically processed, and Type A and B uncertainties were evaluated.
• The results were compared with two other authors, and a good match of mean values was stated.
• Repeated measurements and detailed data evaluation are recommended.

A lot of research has been done in order to investigate heat transfer coefficients of a human body in various postures, wind speeds and wind directions. However, there has not been any reference to measurement reproducibility and measurement confidence intervals. The purpose of this study is to determine heat transfer coefficients of a thermal manikin experimentally, while focusing on the repeated determination of the coefficients and statistical data evaluation. The manikin imitates human metabolic heat production; it measures combined dry heat flux from its surface and also its surface temperature.The major part of the radiative heat flux was eliminated by a low-emissivity coating applied to the surface of the nude manikin. The tests were performed across 34 zones that correspond to parts of a human body. Both standing and seated postures were investigated. The tests were conducted at constant air temperature (24 °C) and constant wind speed (0.05 m s−1). Based on three repetitions of each case, the mean values of heat transfer coefficients, with their uncertainty intervals, were calculated. Next, the results of this paper were compared to the results of similar experimental work of de Dear et al. (1997) and Quintela et al. (2004). A mismatch of the values is up to 1 W m−2 K−1, while an extreme was found on the manikin’s seat with a difference of over 1 W m−2 K−1. The outcomes of this study provide essential information in form of separated values of the convective and radiative heat transfer coefficients that enable us to create detailed computational models of a thermal comfort.