How to Calculate Industrial Fan Power

Understand what fan power involves., Measure the air pressure., Measure the air speed., Measure the diameter., Determine the air flow., Determine the horsepower.

6 Steps 2 min read Medium

Step-by-Step Guide

  1. Step 1: Understand what fan power involves.

    Fan power measures exactly how much energy a fan must receive in order to be able to produce a specific amount of air flow.

    Fan power is a function of both air pressure and air flow and units of horsepower is typically the measure used.
  2. Step 2: Measure the air pressure.

    The very first thing you need to do is measure the fan’s total air pressure.

    This is measured in inches of water gauge (iwg).

    This is the unit of measure which is used for various fan calculations.

    In order to calculate it, you must place one of the ends of a manometer where the fan inlet is.

    The other end of the manometer must be placed at the end of the fan outlet.

    Now you simply measure the difference between the liquid height on both sides of the manometer in order to measure the total pressure. , Now that you have the total pressure, you will have to measure the air speed in feet per second.

    For this you will need a vane anemometer.

    Place the vane anemometer at different points of the fan face, in order to take more than one velocity measurement.

    After you have done that, average all of those readings in order to accurately measure air speed.

    The recommended amount of different velocity measurements is nine, according to the University of Connecticut. , At this point, you must accurately measure the fan diameter in feet.

    When you have the diameter, divide it by 2 and square the result.

    After doing so, multiply it by
    3.14 (or pi) in order to get the fan area. , Now that you know the fan area it is time to multiply it by the air speed of the fan.

    This will give you the air flow in CFM (or cubic feet per minute). , In order to find the horsepower, multiply the air flow by the total pressure and divide the result by
    6356.
  3. Step 3: Measure the air speed.

  4. Step 4: Measure the diameter.

  5. Step 5: Determine the air flow.

  6. Step 6: Determine the horsepower.

Detailed Guide

Fan power measures exactly how much energy a fan must receive in order to be able to produce a specific amount of air flow.

Fan power is a function of both air pressure and air flow and units of horsepower is typically the measure used.

The very first thing you need to do is measure the fan’s total air pressure.

This is measured in inches of water gauge (iwg).

This is the unit of measure which is used for various fan calculations.

In order to calculate it, you must place one of the ends of a manometer where the fan inlet is.

The other end of the manometer must be placed at the end of the fan outlet.

Now you simply measure the difference between the liquid height on both sides of the manometer in order to measure the total pressure. , Now that you have the total pressure, you will have to measure the air speed in feet per second.

For this you will need a vane anemometer.

Place the vane anemometer at different points of the fan face, in order to take more than one velocity measurement.

After you have done that, average all of those readings in order to accurately measure air speed.

The recommended amount of different velocity measurements is nine, according to the University of Connecticut. , At this point, you must accurately measure the fan diameter in feet.

When you have the diameter, divide it by 2 and square the result.

After doing so, multiply it by
3.14 (or pi) in order to get the fan area. , Now that you know the fan area it is time to multiply it by the air speed of the fan.

This will give you the air flow in CFM (or cubic feet per minute). , In order to find the horsepower, multiply the air flow by the total pressure and divide the result by
6356.

About the Author

L

Linda Jordan

A passionate writer with expertise in organization topics. Loves sharing practical knowledge.

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