Convective Heat Transfer Coefficients and Clothing Insulations for Parts of the Clothed Human Body Under Calm Conditions

Abstract

Convective heat transfer coefficlents fbr calm conditions were evaluated f ｛)r each part of the clothed human body ， and compared to those of 中 e nude bod) J ． This was done f-) r both standing and sitting postures ， using a heated therma 【 manikin ， Clothing surface temperatures were measured with an inf 士 ared imaging radiemeter ． The convective heat transfer coefficients were larger for the clothed ma 通 kin than f｛)r the nude manikin ， both f｛)r the whole body and f () r the individual body parts， Large differences were observed in the head， the pelvic region ， the chest ， and the back． 「 This resulted in 40 to 50 ％ increases of convective heat transfer coeC5cients fbr the whole body． Regressbn models for convection heat transfer under ca 】 m condition were presented for use in thermophysiological modeling ． Clothing insu 】 ations were also evaluated and compared between three methods ， The results demonstrate that three methods of estimating clothing ｛ nsulatlon can produce slgnificant ［ y different resu ］ ts、 Keywords ' (／ ' onvective heat tran ． gfer ． clothing insutation， 1召かα 一 red thermography ． human body， thermal con 言 ／-) rt ， natural con りection

Analysis of sensible heat exchanges from a thermal manikin

“…heat felt through temperature variation) from the human body was presented by de Dear et al (1997). Recently, contributions from Oguro et al (2002) attempted to include clothing effects. Within the so-called developed countries, the 24-h cycle of persons engaged in sedentary activities, such as office work, comprises almost equaltime periods of the person in the common occidental postures: standing, sitting or lying down.…”

Theoretical analysis of the effects of human movement on the combined free-forced convection

“…Since the advent of thermal manikin in 1940s, researchers have already conducted several experiments to investigate the detailed knowledge of the heat exchanges between the human body and the environment [2][3][4][5][6][7][8], among which it can be speculated that the environment and the posture of the human body affect more for the convective heat transfer than the radiative heat transfer. During the last decade, experimental researches have been focused on the effects of wind speed, wind direction angle, temperature difference, body posture and limbs swing on the convective heat transfer coefficient [9][10][11][12][13][14]. One of the most noted study was by de Dear et al [15], who measured the convective heat transfer coefficients of the human body under different wind speeds and wind direction angles in the wind tunnel, and correlated the convective heat transfer coefficients as a power exponent function of the wind speed.…”

Measurement of ambient air temperature for evaluation of human heat convective losses

“…Various studies contribute to the determination of the local convection coefficient h c [8,9]. In the case of forced convection, many studies show the same type of correlation: h c = B Á v b .…”