Variable Frequency Drives:
Saving money through energy management programs is something that has been on the table for many years now. Energy usage is a massive expense for any building and with today’s market it looks to only increase with time. In the United States, 50% of our total energy consumed is created by rotating equipment and 65% of that total is consumed by centrifugal or flow related applications such as pumps, motors, fans, blowers and compressors… Variable Frequency Drives are a technology which will allow for significant energy savings on equipment such as this.
What is a VFD?
A variable frequency drive is an electric controller that allows you to control the speed, torque, direction and resulting horsepower on multiple applications, which would otherwise not be possible.
Who are VFD’s for?
Variable frequency drives are a well rounded option and can be a very attractive energy management investment for almost any buildings. Anyone who is looking for an effective way to reduce the cost of running their variable torque motors should look into VFD’s. Some examples of possible applications are cooling tower fans; air handling units, cooling tower pumps, chillers, and circulation pumps.
Benefits of a VFD:
While variable frequency drives have multiple benefits, the most obvious benefit of VFD’s is the ability to have speed control on equipment. Having a VFD in place allows for continuous control which would otherwise not be achievable. Having this continuous control in place allows the VFD to ramp up or decrease the equipment depending on load requirements. Being able to lower the usage depending on the load turns into instant energy savings and allows for a much more efficient system in place.
Another major benefit of a VFD is the ability to change starting characteristics on motors and other equipment. Start up on motors without a VFD in place usually leads to 500 to 600% the equipments full load amps rating. This can affect the buildings peak demand which will have a negative effect on the buildings energy consumption and cost. A VFD allows the motor to be brought up to full speed quickly, with minimal load usage by drawing a smaller percentage of the full load amps. This in turn has a positive effect on motor longevity and peak load demand.
Above is an example of achievable paybacks.
Installation:
Installation of a VFD is something that should be done by only a professional contractor. Installing a VFD requires attention to such details as location, environment, electrical connections, supply voltage and protective devices. Missing any of these details can lead to drive failure or worse. Over 50% of drive failures come from improper installation and can be avoided if a proper contractor were to do the installation.
Summary:
VFD’s are a superior option whenever a load has either a variable torque or variable speed and this makes it applicable for many situations. The ability to ramp up or down based on load requirements turns directly into energy savings and those savings positively affect profit. If VFD’s are not in place already, they should be given serious thought by any building owner, manager or engineer.
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