Environmental Engineering Reference
In-Depth Information
Analysis of Results
Temperature
This is the most contributory factor with a percentage close to 97% (See Table 6). As in
common heat exchangers, since the heat transfer rate is related to the temperature difference,
when the temperature difference between the outdoor and the return airstreams rises, the
sensible heat recovered is higher. (See Figure 11).
Furthermore, next to temperature level 3 (T3) a change can be clearly observed, fact
which represents a different behaviour of the device from heating mode to cooling mode
falling from positive values to negative ones. (See Figure 11)
In Table 7 the average values of sensible heat recovered for the combined system and the
single systems are given and in Table 8 the corresponding ANOVA are shown. In Figure 13
the single devices contribution in comparison with combined system contribution is given.
Table 7. Single factors mean values for the combined system
and the single systems separately
Sensible Heat Recovered
(W)
Combine
d System
Evaporative Cooling System
Heat Pipes System
Mean
Values
Factors
Factors
Mean values
Factors
Mean Values
V1
-1124.22
V1
-1104.45
V1
-19.77
V2
-1439.77
V2
-1402.66
V2
-37.10
V3
-1691.29
V3
-1640.12
V3
-36.35
T1
977.19
T1
878.70
T1
98.49
T2
577.93
T2
562.59
T2
59.79
T3
-203.78
T3
-251.93
T3
48.14
T4
-785.89
T4
-765.58
T4
-20.30
T5
-1220.62
T5
-1189.54
T5
-31.07
T6
-1984.62
T6
-1920.03
T6
-64.59
T7
-2591.93
T7
-2503.58
T7
-88.35
T8
-3491.74
T8
-3366.12
T8
-125.62
T9
-4042.37
T9
-3886.21
T9
-156.16
Table 8. ANOVA (combined system and single systems separately)
Sensible
Heat
Combined System
Evaporative Cooler
Heat Pipe System
Factors
DoF
SS
%
SS
%
SS
%
V
2
1453205.1
1.9
1296814.6
1.9
1727.2
0.9
T
8
73561119.0 96.7 67024437.0 96.5 181267.1 97.0
VxT
16
1065784.6
1.4
1102928.9
1.6
3956.1
2.1
Error
0
0.0
0.0
0.0
0.0
0.0
0.0
Total
26
76080109.0 100.0 69424180.0 100.0 186950.5 100.0
