Environmental Engineering Reference
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Figure 9: Wind condition numbers corresponding to heat exchanger thickness
exceeding 0.2 m based on various fi n pair collocations [21].
is the most compact and lightest under this circumstance. Moreover, it can be
found in the fi gure that if the airside fi n size is changed and the liquid fi n size is
kept unchanged, there will be an obvious infl uence on the selected heat exchanger
thickness and weight; while if the liquid side fi n is changed instead of the airside
one, the change will be comparatively smaller.
It can be found from the above computing results, the heat exchanger adopting fi n
pair cc1 and ch1 can reach its lightest and most compact structure, which is, thus, in
favor of operating at a high altitude for the generating set. Considering that the liquid
side pressure drop is far less than that of the cooling medium running through the
generator and the control converter, this optimization focuses on the weight of the
cooling system. From computing results, the fi n pair cc1 and ch1 are adopted as
the optimum fi n pair. The results show that it would obtain a more effective fi n
function and comparatively higher fi n effi ciency by selecting low and thick fi n on
the liquid side with a large heat transfer coeffi cient and by selecting the high and
thin fi n on the small-heat-transfer-coeffi cient airside.
The relationship, shown in Fig. 10 [21], between the computed values of the
parameters and the wind speeds under 18 wind conditions adopting fi n pair cc1
and ch1 are computed by the commercial software, MATLAB. It can be concluded
from the modeling result that as the wind speed rises up, the computed values of
the heat exchanger thickness and the corresponding heat exchanger weight decline
gradually, while the pressure drop on the liquid side and the heat exchanger's effi -
ciency increase continuously. The maximum heat exchanger thickness is 116 mm,
appearing at 10 m/s wind speed, and the pressure drop on liquid side is 341.5 Pa
which meets the system pressure drop requirements.
The above optimization of liquid cooling systems is limited to the computed
result of heat transfers and structural dimension and weight, and based on the
hypothesis of steady working condition and thus no comprehensive conclusion
can be drew for the dynamic property, power consumption and operating cost of
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