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Article Excerpt
INTRODUCTION
The PMV model is used to predict the thermal sensations of a large group of people using six variables: activity, clothing, air temperature, mean radiant temperature, air velocity, and humidity (Fanger 1982). The advantage of the PMV model is that it is a flexible tool that includes all the major variables that influence thermal sensation and can, therefore, be used in indoor environments with widely different activities and different clothing habits (Fanger and Toftum 2002; Becker et al. 2003) and in other fields (Yang and Su 1997; Aynsley 1999; Jang et al. 2007; based on a large number of subjects (over a thousand). Can it be used for a small number of people? In addition, the mean body temperature of the subjects--an important physiological variable to include in the external temperature of clothes for PMV calculation--are uniformly fixed once their activity states are determined, regardless of changes in the thermal environments. There exist great differences in skin temperature among people. Hence, the fixed mean skin temperature (MST) will make the PMV model deviate greatly from actual situations.
In this paper, the skin temperatures of male and female subjects were investigated using fourteen measurement methods. The differences of MSTs between the male and the female, as well as the variation patterns of partial skin temperatures under different thermal conditions, were analyzed according to the experimental data. Meanwhile, the validity of the PMV model was studied using different MSTs based on different measurement methods.
The objectives of this study are mainly to discuss the following questions:
* What impact does the changed ambient air temperature have on the MST of people with little clothing? And what is the difference for males and females?
* How does the MST influence the validity of the PMV model?
* Which measurement method of MST is best for application of the PMV model?
MEASUREMENT METHODS OF MEAN SKIN TEMPERATURE
The methods of measurement for the MST suggested by Mitchell et al. (1969) were adopted in this study (see Figure 1). The fourteen calculation formulas for the MST that were investigated (Mitchell et al. 1969; Choi et al. 1997) are listed as follows:
[FIGURE 1 OMITTED]
Burton (3 points):
[t.sub.sk, mean] = [0.5t.sub.sk, C] + [0.14t.sub.sk, F] + [0.36t.sub.sk, J] (1)
Ramanathan (4 points):
[t.sub.sk,mean] = [0.3t.sub.sk, C] + [0.3t.sub.sk,D] + [0.2t.sub.sk,H] + [0.2t.sub.sk,J] (2)
Newburg/Spealman (4 points):
[t.sub.sk,mean] = [0.34t.sub.sk,C] + [0.15t.sub.sk,F] + [0.33t.sub.sk,H] + [0.18t.sub.sk,J] (3)
Houdas (5 points):
[t.sub.sk,mean] = [0.07t.sub.sk,C] + [0.175t.sub.sk,E] + [0.175t.sub.sk,N] + [0.19t.sub.sk,D] + [0.39t.sub.sk,P] (4)
Palmes/Park (6 points):
[t.sub.sk,mean] = [0.14t.sub.sk,B] + [0.19t.sub.sk,C] + [0.19t.sub.sk,N] + [0.11t.sub.sk,F] + [0.05t.sub.sk,G] + [0.32t.sub.sk,H] (5)
Hardy/DuBois (7 points):
[t.sub.sk,mean] = [0.07t.sub.sk,A] + [0.35t.sub.sk,E] + [0.14t.sub.sk,F] + [0.05t.sub.sk,G] + [0.19t.sub.sk,H] + [0.13t.sub.sk,J] + [0.07t.sub.sk,K] (6)
Gagge/Nishi (8 points):
[t.sub.sk,mean] = [0.07t.sub.sk,A] + [0.175t.sub.sk,C] + [0.175t.sub.sk,M] + [0.07t.sub.sk,D] + [0.07t.sub.sk,F] + [0.05t.sub.sk,G] + [0.19t.sub.sk,H] + [0.2t.sub.sk,J] (7)
Nadel (8 points):
[t.sub.sk,mean] = [0.21t.sub.sk,A] + [0.1t.sub.sk,C] + [0.17t.sub.sk,E] + [0.11t.sub.sk,M] + [0.12t.sub.sk,D] + [0.06t.sub.sk,F] + [0.15t.sub.sk,H] + [0.08t.sub.sk,J] (8)
Houdas/Colin (9 points):
[t.sub.sk,mean] = [0.20.sub.sk,B] + [0.05t.sub.sk,C] + [0.125t.sub.sk,E] + [0.2t.sub.sk,M] + [0.1t.sub.sk,D] + [0.05t.sub.sk,F] + [0.125t.sub.sk,H] + [0.075t.sub.sk,J] + [0.075t.sub.sk,Q] (9)
QREC (10 points):
[t.sub.sk,mean] = [0.10.sub.sk,B] + [0.125t.sub.sk,C] + [0.07t.sub.sk,D] + [0.07t.sub.sk,F] + [0.06t.sub.sk,G] + [0.125t.sub.sk,H] + [0.15t.sub.sk,J] + [0.05t.sub.sk,K] + [0.125t.sub.sk,N] + [0.125t.sub.sk,R] (10)
Colin/Houdas (10 points):
[t.sub.sk,mean] = [0.06.sub.sk,A] + [0.12t.sub.sk,C] + [0.12t.sub.sk,E] + [0.12t.sub.sk,M] + [0.08t.sub.sk,D] + [0.06t.sub.sk,F] + [0.05t.sub.sk,G] + [0.19t.sub.sk,H] + [0.13t.sub.sk,J] + [0.07t.sub.sk,K] (11)
Hardy/DuBois (12 points):
[t.sub.sk,mean] = [0.07.sub.sk,A] + [0.0875t.sub.sk,C] + [0.0875t.sub.sk,E] + [0.14t.sub.sk,F] + [0.05t.sub.sk,G] + [0.095t.sub.sk,H] + [0.065t.sub.sk,J] + [0.07t.sub.sk,K] + [0.0875t.sub.sk,N] + [0.095t.sub.sk,P] + [0.065t.sub.sk,Q] (12)
Stolwijk/Hardy (Unweighted 10 points):
[t.sub.sk,mean] = [1/10][SIGMA]([t.sub.sk,A] + [t.sub.sk,C] + [t.sub.sk,E] +[t.sub.sk,M] + [t.sub.sk,D] + [t.sub.sk,G] + [t.sub.sk,H] + [t.sub.sk,P] + [t.sub.sk,Q] +[t.sub.sk,K]) (13)
Mitchell/Wyndham (Unweighted 15 points):
[t.sub.sk,mean] = [1/15][SIGMA][[t.sub.sk,A] + [t.sub.sk,C] + [t.sub.sk,D] +[t.sub.sk,E] + [t.sub.sk,F] + [t.sub.sk,G] + [t.sub.sk,H] + [t.sub.sk,J] + [t.sub.sk,K] +[t.sub.sk,L] + [t.sub.sk,M] + [t.sub.sk,N] + [t.sub.sk,P] + [t.sub.sk,Q] + [t.sub.sk,R] (14)
PMV MODEL
The PMV index, which was first developed by Fanger (1982) and has widely been used to evaluate human thermal comfort (Jang et al. 2007; Kosonen and Tan 2004), represents most...
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