Please read this detailed description on DC Fans and it's uses!

1. Choosing the Best DC Fans for your
Application
To keep your sensitive computer parts from
overheating, the use of DC fans is a cool solution for
your hardware.
Your computer hardware is sensitive to high
temperature environments, which could reduce their life
span and effectiveness.
In order to get the equation right and keep temperatures
down, a fan is crucial.
When it comes to choosing what type of fan to use,
some people prefer DC fans over AC fans, and not
without reason.

2. DC fans have greater durability and their life span is
longer than their AC counterparts, and cost-wise they
are cheaper as well.
Selecting the best fan for your application requires
some serious thought on your part.
You need to analyze the airflow required to keep the
thermal equation in control.
Temperature Analysis
To choose the right fan, first you need to analyze the
amount of heat that will be generated by the system
during operation.
Next you need to identify the different heat generating
units, thermal resistance, and the amount of heat that is
dissipated.
Lastly, you should determine the case temperature, and
the range of maximum and minimum conditions the
system can operate at.
This will allow you to assess the volume of air required
to cool the system.
Check the System Resistance
No matter what the fan manufacturer’s claim is
regarding the max inflow of their products, you are
likely not going to get what is advertised.

3. In an enclosed environment, the back pressure is bound
to resist the flow, therefore reducing the max flow.
Please be aware of the resistance level of your system,
which you can analyze by attaching the airflow
chamber to your system, and measuring the amount of
air resistance built up in the chamber.
Analyze the System
Different applications have different mechanisms,
structure, hardware, material, and mounting methods
upon which they work.
Therefore, you need to understand the features of each
application. After analyzing these factors, you should
choose which fan to opt for.
For instance, previously computers used a
92x92x25mm fan for cooling the internal system.
Then came the age when fan designs of 60x60mm and
80x80mm began getting used by engineers.
DC Fan’s Correct Voltage
Next, choose the correct voltage. Every product comes
with different voltage specifications, and some products
have a bad habit of coming with industry specific
voltages as well.

4. In the telecommunication industry, 48 volt DC fans are
used for the components that require higher power.
If a low voltage fan is used, it will get burnt out. This
could lead to a system shut down or failure due to
overheating.
Other Features to Check for your DC Fans
Other properties which you can check for are the noise
level a fan generates and the bearings used in the fan.
You can choose a dual ball bearing fan, which will last a
long time, although you have to pay a higher price for
that.
Next, you can choose a fan assembled with ball/sleeve
bearings which can operate up to 50,000 hours.
Lastly, there is the least expensive one which has only a
sleeve bearing, and has a life span somewhere around
30,000 hours.
If you check out the above parameters, you can
calculate the equation for choosing the right fan to cool
your specific systems.