12 +jarrah+ +15+ways+to+improve+cooling+efficiency

8/2/2019 12 +Jarrah+ +15+Ways+to+Improve+Cooling+Efficiency

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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

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