2007, Piran, Slovenia

Thermal comfort
and heart rate using a polar transducer. All objective measurements were recorded 1 second
intervals throughout the trial.
Subjects were provided with a clothing ensemble (boxers, sports trousers, and a sweat shirt
worn over the APV), and supplied their own athletic footwear. The thermal environment
within the APV was modified throughout the trial. Figure 1 shows the 4 different RH profiles
for the APV. The temperature in the APV was maintained at 35 o C, while the RH of the
microclimate was modified at four controlled rates of change (2.12, 4.25, 7.5, 15 %/minute),
separated by 10 minute static periods. Exposure to these different controlled rates was
randomized between subjects; each subject experienced a full cycle (increasing and
decreasing) at each rate.
Thermal Perceptual Scales: Local and whole body thermal perceptions were captured during
static and dynamic periods. The visual analog thermal perceptual scales (VAS), were used to
investigate local and whole body temperature sensation and thermal comfort in dynamic
(Zhang, 2003), asymmetric environments. The scales were computerized and displayed via a
touch screen monitor with a stylus pen acting as the mode of data entry.
RESULTS AND DISCUSSION
Individual thermal perception profiles and average (n=8) profiles were plotted for each
perception and ramp rate an example for TTS is shown in Figure 2. A baseline of the torso
perceptions was selected for each subject at the 25% RH static level, this baseline was
subtracted from the peak perceptions at the static 85% RH level. Using this metric the TTS
perception was found to be most responsive to changes of RH in the vest, TTC showed only
61% of the change of TTS and TSW only 32%. A further trend can be identified from Figure
2 that suggests subjects displayed an overshoot response previously identified by de Dear et al
(1993). The response to “RH cooling” appears to be stronger than to “RH heating”, further
work is necessary to confirm this finding. Significant differences were observed between the
three fastest ramp rates and the slowest; however, no differences could be determined within
the three fast rates. Correlations of thermal perception scales were modelled using an
ANOVA type analysis at an alpha=0.05. The following variables were identified as
significant for the whole body
perceptions: mean skin
temperature (MST), core
temperature (CT), subject, and test
time. The variables found
significant for the torso thermal
perceptions were: mean vest skin
temperature (MVST), core
temperature (CT), change in mean
vest skin temperature over 120
seconds (DMVST), subject, test
time, and chest RH. Results are
shown in Table 1.
Thermal Perception Values
120
110
100
90
80
Figure 2: Average Profiles for TTS at Different Ramp Rates
70
60
50
15%/min
4%/min
7%min
2%/min
Slightly Cool
0 10 20 30 40 50 60 70
Time Minutes
Warm
Slightly Warm
Neutral
A general linear model was constructed using the variables identified above, regression
coefficients and confidence internals at an alpha=0.05 were calculated. A regression plot for
TTS is shown in Figure 3. As reported earlier smaller changes were observed in TTC when
compared to TTS, these differences may account for the lower R 2 of TTS (0.78) as compared
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