Environmental Engineering Reference
In-Depth Information
set, and thus facilitates the generating effi ciency. Meanwhile, the design of the sealed
nacelle prevents the invasion of wind, blown sand and rain, creating a good working
surrounding for the wind turbine, which greatly extends the duration of the devices.
4 Design and optimization of a cooling system
As has been mentioned above, the increasing power capacity of wind turbines calls
for a matching cooling system. With the widespread use of MW wind turbines, the
liquid cooling system has been prevalently used in current wind turbines. Accord-
ingly, the design and optimization of a liquid cooling system is briefl y introduced
in this section. Since currently very few researches are conducted on the heat dis-
sipating regularity in wind turbine operation and experimental data are scarce,
the following research is based on a steady working condition, where the heat
production of the generating set is under a steady-state condition. According to the
ambient conditions and technical requirements provided by wind turbine compa-
nies, the liquid cooling system is designed and analyzed under the maximum heat
load. On this basis, the commercial software, MATLAB, is used for the purpose
of optimal design, and the interaction and mechanism of action are investigated
among parameters, such as wind speed, fi n combinations, etc. These researches
are somehow valuable to be referred to for the design and optimization of the MW
wind turbine cooling system.
4.1 Design of the liquid cooling system
The cooling system of one certain MW wind turbine is shown in Fig. 5. This sec-
tion proposes the design of the liquid cooling system for the generator and the
control converter, which is shown as follows [14]. And as the designs of oil cool-
ing system and liquid cooling system are basically the same, contents on those will
be excluded due to restriction of the article length.
4.1.1 Given conditions
This MW wind turbine is located in the coastal area with a temperature ranging
from
35 to 40°C. The start-up wind speed is 4 m/s, while the shutdown wind speed
is 25 m/s. The relationship between the generated output
P
and wind speed
V
c,in
is
shown in Fig. 6. Other initial parameters are shown in Table 2. The objective is to
design a liquid cooling system to meet the cooling demands of the wind turbine and
to control its structural sizes to be most favorable for the durable operation of the
wind turbine based on the giving ambient conditions and technical requirements
from the wind turbine companies. Focusing on this objective, this section introduces
how to select key components and explain the method of optimal computation to
obtain the size of the ethylene glycol aqueous solution-air-typed heat exchanger.
−
4.1.2 Selection of the cooling medium
To meet the technical requirement of
35°C for the minimum ambient temperature
in winter, the ethylene glycol aqueous solution with a concentration of 50% and a
freezing point of
−
−
38°C is picked according to Cao [15] and Tan [16].
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