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COOLING TECHNOLOGIES GROUP OF
NMB TECHNOLOGIES CORPORATION
15 Ways to Improve Cooling Efficiency
When using Airmoving Devices
USA Headquarters Chatsworth, CA Fan Manufacturing Shanghai, China
Dr. Yousef Jarrah
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#1: Use the Largest and thickest fan possible
The larger the fan size the higher the efficiency and the
lower the noise.
small fan efficiency = 10%
large fan efficiency = 30%
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#2: Use thermal data to control fan speed
Size the fan for the worst case cooling condition, but operate
the fan for the optimum cooling required.
Example: A 19 rack mount system uses four 2415KL (70mm x 70mm x38mm) fans
Nominal airflow required: 40 CFMMaximum airflow required: 60 CFM
(failure mode or high temp operation)
Power required at max airflow: 16.6 WattsPower required at nominal airflow: 4.9 Watts
One year operating costs for 4 fans at max airflow: $58.17
Power required at nominal airflow: $17.17
Difference: $41 per year*
* Assumes $0.10 per KW/hour charge (Phoenix prices) 24 hr operation 7 days a week
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#3: Allow for sufficient Air plenum
Exhaust
Inlet
Minimize downstream blockage
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#4: Minimize the turns the airflow needs to take to cool the system
Exhaust
InletSide View
Circuit Cards
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#5: Pick the correct type of rotating turbomachine
Airflow
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#6: Operate the axial fan at the peak efficiency point
Peak Efficiency point
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#7: Operate motorized impellers at the peak efficiency point
Peak Efficiency point
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This is effective for axial fans too!
#8: Use Inlet Rings for motorized impeller solutions
#9: Minimize the gap between the inlet ring and the motorized impeller
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#10: Use scrolls for motorized impeller solutions where the
air is exhausting out in one direction
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#11: Minimize obstructions on the inlet/exhaust of the fan.
Airflow
Fingerguard
Fingerguard
Airflow
Fan Tray Design Example
Without finger guard,efficiency improves x% !
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Airflow
Electronics
Electronics
Electronics
Loss
Loss
#12: Minimize dead air spots in the system
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This eliminates circulating airflow
Air recirculation will hurt
Performance.
Much better.
#13: Size the inlets and outputs appropriately
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#14: Ask for an impeller blade customized for the system
impedance point for maximum efficiency
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15: Ask airmover vendors for higher efficiency motor designs
(And be prepared to pay a little more in up front costs)
Typical motor efficiency of
standard fan motors: 60%
Stronger magnet material Three phase driver designs
Optimized stator design
Motor efficiency can reach: 85%
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#1: Use the largest and thickest fan possible
#2: Use thermal data to control fan speed
#3: Allow for sufficient air plenum
#4: Minimize the turns the airflow needs to take to cool the system
#5: Pick the correct fan for the direction of airflow needed
#6: Operate the axial fan at the peak efficiency point
#7: Operate the motorized impellers at the peak efficiency point
#8: Use inlet rings for motorized impeller cooling applications
#9: Minimize the gap between the inlet ring and the impeller#10: Use scrolls for motorized impeller solutions where the air isexhausting in one direction
#11: Minimize or eliminate finger guards and other obstructions
#12: Eliminate Dead air spots in the system#13: Size the inlets and outlets appropriately
#14: Ask for an impeller blade customized for the system operatingimpedance point
#15: Ask airmover vendors for higher efficiency motor designs in theirairmoving solutions (and be prepared to pay a bit more up front)
SUMMARY
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THANK YOU !
Cooling Technologies Group