Variable Frequency Drives
Variable Frequency drives are one of the most cost effective ways of saving a large amount of money every month. If a fan or pump speed is reduced to 75 percent of the rated speed, power consumption can be reduced by as much as 42 % of the rated power. This follows The Affinity Law. Older systems were installed without VFD’s, and in most cases, they do not need to run at full speed.
In a fan system, this would be throttled back with dampers, or vanes in larger fans. In chillers, the inlet guide vanes lowered the capacity while the motor was still at full speed. In pumps, the discharge line would be throttled back to keep the amps under the nameplate rating, or a bypass valve would be installed. At lower loads, most systems do not need to run at full capacity. The energy loss due to these type of things adds up in a hurry.
Depending on each application, we install pressure transducers, gpm meters, or other sensors to calculate a building load. With this information, we can program a system to automatically adjust its speed throughout the day to accommodate the load on the building.
Starting an induction motor without a VFD causes high inrush current. It takes an enormous amount of energy to get a motor spinning from a stop. This increases as the size of fan or pump increases. A VFD will smooth this out and ramp this motor up at a adjustable rate. This saves energy, reduces heat on the motor, increases the life of motor, bearings, pulleys and belts. Saving money during normal operation and saving money on repair and maintenance costs.
- ACS can maintain, service, and install VFD’s of all manufactures.
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ACS also installs McQuay chillers with Variable Speed Turbocor compressors. Danfoss Turbocor’s family of compressors, the world’s first totally oil-free compressors, are specifically designed for the Heating, Ventilation, Air Conditioning and Refrigeration (HVACR) industry. The convergence of aerospace and industrially proven technologies which include magnetic bearings, variable-speed centrifugal compression and digital electronic controls, enable the Turbocor family of compressors to achieve the highest overall efficiencies for middle-market, water-cooled, evaporatively cooled and air-cooled HVACR applications. - ACS can integrate VFD’s with the building management system through Lonworks, Bacnet, or Modbus.
