2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
were dressed on the manikin similarly. Heat flux supplied to each manikin zone was recorded
on a notebook computer until the experiment ended. In the stomach zone, we also recorded
the skin temperature of 3 points, each covered by refrigerant, and a point in the area which
was not covered by a refrigerant by a flat type thermistor.
RESULTS
The heat fluxes of 4 zones in torso were shown in Figure 1. Before dressing with the cooling
vest, heat fluxes were steady in both refrigerant types. On attaching the cooling vest, the heat
fluxes increased sharply and then decreased gradually. Especially in the back and stomach,
type B absorbed more heat than type A in the first 3 hours (Figure 1).
Heat Flux (w/m 2 )
H eat Flux (W /m 2 )
Figure 1: Heat flux of torso before and after the attachment of cooling vest. At Time 0, the
cooling vest was attached to the manikin after having reached the steady state with T-shirts,
long trousers and fire-fighter’s clothing.
Heat was calculated by integrating heat flux with time. The theoretical heat needed to warm
the refrigerants was also calculated with specific heat and heat of fusion of paraffin. Though
theoretical heat of type B was smaller than that of type A, type A had more cooling power
than type B during the first 3 hours. In the first 3 hours, 48% of cooling power of type A was
used in comparison with 79% of type B.
Figure 2: Total extra heat supply to torso when wearing cooling vest with Type A or Type B.
448
200
150
100
50
Type A-
Shoulder
Type B-
Shoulder
0
-2 200 0 2 4 6 8 10 12 14 16 18 20
150
100
50
Type A-
Back
Type B-
Back
0
-2 0 2 4 6 8 10 12 14 16 18 20
Time (hour)
Heat (Kcal)
25
20
15
10
5
200
150
100
50
Type A-
Chest
Type B-
Chest
0
200 -2 0 2 4 6 8 10 12 14 16 18 20
Type A-
150
Stomach
100
50
Type A
Type B
0
01234567891011121314151617181920
-5
Time Hour
Type B-
Stomach
0
-2 0 2 4 6 8 10 12 14 16 18 20
Time (hour)