Why is Energy Efficiency Important?

Drives provide additional savings by reducing the speed of the motor and therefore the horsepower required to operate. Longer motor life, improved power factor, reduced noise and greater flexibility also contribute to lower operating cost.

Fans and Pumps consume the same amount of energy as 30% of the automobiles driven in the United States.

Building control systems have to be designed for the worst case scenario; to be able and either cool or heat a building on the hottest and coldest days of the year. Average systems however are not required to output at maximum level during normal operation.

80% of the time pumps and fans operate at 60% of their full capacity.

Why VFD Drives Make Sense

• Federal mandates for energy efficiency.
• Energy savings over the life of the system far outweigh initial system installation cost.
• Reduced mechanical stresses on mechanical systems such as ducts due to lower pressure spikes as a result of the soft start capability with drives.
• Motors and V-Belt stresses are also lower and therefore life of these components is increased.
• Increased system uptime due to less maintenance.
• Enhanced process control functions.
• Audible Noise reduction.

Affinity Laws in Action

Energy savings are possible because of the affinity laws that govern the operation of centrifugal pumps and fans. Compared with throttled valves and bypass systems, speed reduction provides significant energy savings at partial load. To reduce output from a pump or fan in a fixed speed application an Inlet Guide Vane for a Fan or a Pump Valve must be used. This can result in excessive energy consumption over using a variable speed drive.

Running a fan / pump at 60% operating speed or volume requires only 22% input power.

At 100 Hp, a variable speed drive operating a pump / fan at 60% speed will result in over $20,000 a year in energy savings when compared to running at 100% flow volume. This can pay for the installation of a drive in less than six months!