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

journal article in Web of Science

en

A lot of research has been done in order to investigate heat transfer coefficients of human body in various postures, wind speeds and wind directions (e.g., [1-15]). However, there has not been any reference to measurement reproducibility and measurement confidence intervals. The purpose of this study was to determine heat transfer coefficients of a thermal manikin experimentally, while focusing on the repeated determination of the coefficients and statistic data evaluation. The manikin imitates human metabolic heat production; it measures a combined dry heat flux from its surface and also its surface temperature. The major part of the radiative heat flux was eliminated by 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) environment. Based on three repetitions of each case, the average values of heat transfer coefficients with their confidence intervals were calculated. Next, the results of this paper were compared to the results of similar experimental work of de Dear (de Dear et al. 1997) and Quintela (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 on how to create detailed computational models of thermal environment with regards to thermal comfort where separate values of convective and radiative heat transfer coefficients are required.

A lot of research has been done in order to investigate heat transfer coefficients of human body in various postures, wind speeds and wind directions (e.g., [1-15]). However, there has not been any reference to measurement reproducibility and measurement confidence intervals. The purpose of this study was to determine heat transfer coefficients of a thermal manikin experimentally, while focusing on the repeated determination of the coefficients and statistic data evaluation. The manikin imitates human metabolic heat production; it measures a combined dry heat flux from its surface and also its surface temperature. The major part of the radiative heat flux was eliminated by 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) environment. Based on three repetitions of each case, the average values of heat transfer coefficients with their confidence intervals were calculated. Next, the results of this paper were compared to the results of similar experimental work of de Dear (de Dear et al. 1997) and Quintela (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 on how to create detailed computational models of thermal environment with regards to thermal comfort where separate values of convective and radiative heat transfer coefficients are required.

Thermal manikin, Heat transfer coefficients, Experimental work, Thermal comfort, Confidence intervals

19.04.2016

Elsevier Inc.

0894-1777

77

2016

257–264

8