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Application Mistakes to Avoid When Using a Fan or a Blower

using fans and blowers on enclosures

With the primary goal of moving air through the enclosure, how do you know whether a fan or blower is the better choice for an application? Take a few moments to compare the similarities and differences of each cooling device in order to  make the most informed decision of which is best for you.

 

If ambient air is clean and cool enough to maintain the necessary temperature within an enclosure, open-loop cooling systems can be utilized. With differences mainly in design and operation, fans and blowers are both examples of open-loop cooling devices. Knowing more about their particular operation will help avoid guesswork. Both options are typically easy to install, require little maintenance and are the most economical cooling solution available. Since the surrounding air should adequately accomplish the heat dissipation needed, this cooling method avoids the necessity for a more complex and costly cooling system, such as an air conditioner or heat exchanger. Additionally, due to the footprint, these units may allow for a smaller enclosure to be used, thus allowing for cost savings that would have been associated with using a larger cabinet.

 

Features common to both fans and blowers

 Fan and blower performance is measured using the same methodology. The amount of airflow is the chief concern, typically expressed in cubic feet per minute (CFM), and corresponds to the air volume a device is capable of moving. However, the amount of air a device can move alone is not enough information to select a unit. In every installation, there will be some level of resistance to the airflow, known as static pressure. This could be caused by a tightly packed enclosure or the distance heated air must travel to escape the enclosure through an opening.

 

Static pressure is expressed in inches of water column; in all types of air moving devices, the airflow will decrease as static pressure increases. To remove heat adequately, a properly sized unit will provide the right combination of CFM of air and have adequate “push” against the static pressure. When making a product selection, refer to performance charts (such as the graph below) for guidance.  

 chart2.gif

 

What are the major differences between fans and blowers?

 

Features of Fans:

  • Use an axial blade design to move the air
  • Typically used to move high volumes of air against low static pressure systems
  • Occupy minimal cabinet space and will move a substantial volume of air where    flow is virtually unimpeded
  • Normally use air filtration
  • Lower cost than blowers
  • Provide a wide air circulation path

 

fans.gif

 

blower.gif

Features of Blowers:

  • Use a “squirrel cage” type impeller
  • Required for medium to high static pressure systems
  • Designed to move air in more densely packed spaces
  • Incoming air filtration is usually optional
  • More costly than fans, but provide a stronger airflow to circulate cooling around heated components
  • Sometimes used to deliver air to a specific area or hot spots

 

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While fans and blowers have similarities, such as both devices use ambient air to dissipate heat, they are different in their ability to perform under various conditions. When considering all factors, individual unit performance graphs or interactive sizing programs can be helpful tools when determining the most appropriate air mover for a specific application. If you feel more information is needed before you can make a decision, consult with an enclosure cooling expert who will help you choose the cooling system that is best suited for your project.

Topics: Cooling basics, Fans and Blowers

Steve Coulton

Written by Steve Coulton

Steve is the Sales and Marketing Manager at Kooltronic

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