ACHRNEWS

Oil-Less Compressor Uses Magnetic Bearings

May 27, 2002
Turbocor's TT300 compressor is totally oil-free.
Contractors familiar with oil-lubricated compressors may want to start thinking magnetically.

Turbocor, from Montreal, PQ, Canada, is introducing a compact centrifugal compressor that uses magnetic bearings and variable-speed drives to deliver what the company claims to be better efficiencies than conventional oil-lubed recips, scrolls, and screws.

According to the company, “With a nominal 60- to 90-ton capacity range, the oil-free TT300 achieves the highest efficiencies for middle-market air-cooled chillers and rooftop systems, including water-, air-, and evaporatively cooled applications.”

Proponents of the concept contend that replacing oil-lubricated bearings with magnetic ones eliminates high friction losses, mechanical wear, and the need for oil management systems. They maintain that could mean energy savings of 30% or more.

Magnetic bearings levitate the rotor shaft.
Turbocor said the TT300’s one main moving part, the rotor shaft with impellers, is levitated during rotation by a digitally controlled magnetic bearing system. Position sensors at each magnetic bearing provide real-time feedback to the bearing control system, ensuring centered rotation, the company said.

The use of high-speed, variable-frequency operation is designed to afford part-load efficiency, compactness, and soft-start capacity. An inlet guide vane assembly trims compressor capacity and is digitally integrated with the variable-speed control to optimize energy efficiency and compressor performance throughout a wide range of load and temperature conditions, the company stated.

The compressor’s onboard digital controller manages compressor operation while providing external control. Web monitoring can be done through an RS-485 connection. It also is said to provide many of the control functions previously performed by power and control panels of chillers or rooftop packages.

The compressor is made from what the company calls “aircraft grade” aluminum castings with thermoplastic electronics enclosures. The unit weighs 135 kg, about 80% less than competitive compressors, according to company officials. It is also 50% smaller, the company said.

The unit uses R-134a refrigerant. A plug-and-play setup features the same standard suction, discharge, and economizer ports as conventional compressors, said the company.

Turbocor was formed in 1993 with the intent to bring high-efficiency compressor technology to the hvacr “middle market.” Its manufacturing plant in Dorval, PQ, was built in 1999 and is largely automated. It is capable of producing 10,000 units a year, according to company officials.

For more information, contact Turbocor at 717-699-5418 or visit ,www.turbocor.com (website).

Publication date: 06/03/2002