HVAC Variable Speed Drives
Smart Motors – Saving Energy by Running Motors Smart Instead of Hard
Increase Motor Efficiency with Variable Speed Drives
Yet another HVAC innovation that may save you money and help your HVAC equipment last longer and work more efficiently is the Variable Speed Drive (VSD) or Variable Frequency Drive (VFD). VFD and VSD drives control the speed of motor-driven equipment such as fans, pumps, compressors, etc. That doesn’t sound very sexy, until you think about how motors work, and how expensive it is to run them, and then it becomes much more appealing. Motors generally have two speeds, full speed and stop. VFDs and VSDs allow the motors to run at varying speeds to produce the precise level of comfort you need in a much more efficient way.
To put a number on it, motors running at full speed use not two times, but nearly 8 times the energy of a motor running at half speed. Consider the impact of that on your electric bill… Because the majority of time, motors don’t need to be running at full speed, systems without VFD or VSD drives use dampers and valves to get rid of the extra cooling or heating. It’s similar to flooring the gas pedal on your car and using the brakes to regulate speed. In addition to being an enormous waste of energy, it’s also very hard on the car. The drives help reduce that wear by allowing the motor to start more slowly and maintain a managed pace. The drives function like a brain for the motor. Using sensors, the determine how fast and how long the motor must run to maintain desired temperatures, airflow, etc. Your motor is still able to provide you with ideal comfort but at much less cost. See the schematic below to see how the system works.
In addition to saving energy and reducing wear and tear on your equipment, the drives can also alert you of potential problems or needed maintenance, minimizing equipment downtime. In some cases repairs can be done even before anyone notices a problem. Advance Air has the ability to show you the savings that you will recognize when you install a VFD/VSD system in your building.
|Sample VFD/VSD Energy Savings Analysis Report|
|Project Reference: ABC Company|
|Equipment Reference:||Recirculation Pump #2|
|Motor nameplate HP:||75 HP|
|Cost of Electrical Power:||$0.11 per kW-hr|
|Existing System Flow Control Method:||Throttling Valve|
|Typical Hours of Operation Per Day:|| |
|Total annualized hours of operation:||8,395 hours|
|Estimated Cost of Operation using Throttling Valve (Existing System):||$44,793|
|Estimated cost of operation with VFD:||$17,747|
|Energy Savings using VFD:||$27,047 (60%)|
|Report Provided by Honeywell and Control Consultants Inc.|
For more information, or to find out if VFD/VSDs can help your business, call Advance Air at 508-763-3738 or send an email to firstname.lastname@example.org.