Spool compressor hits peak note

USA: The company behind a new refrigeration and air conditioning compressor design claims that its latest prototype has achieved market level energy efficiency.

Joe Orosz, chief operating officer at Torad, revealed the latest data and performance characteristics of his company’s 6th generation spool compressor prototype at this week’s International Compressor Engineering Conference at Purdue University.

“The performance characteristics, low cost structure, and low manufacturing capital requirements make the spool compressor a winning platform for refrigerant compression across a broad range of applications and capacities,” he told delegates.

Greg Kemp, Torad’s chief executive officer said, “Empirical data and numeric modelling indicate the spool compressor will have a significant market advantage over the scroll’s mid-to-high capacity range and over the screw’s low capacity range.

Described as being smaller, lighter and cheaper to manufacture than current technology, Torad’s spool compressor resembles a rotary vane compressor. It has four main components: rotor, main housing, vane, and bearing housing. Unlike scroll and screw compressors employing complex geometries, the components can be manufactured utilising lower cost capital equipment and easily scaled for larger sizes. The design is said to be uniquely durable with significant advantages in capacity density and variable speed operation.

However, while being compact with a high displacement density like a rotary compressor, it is said to reduce the friction between the vane tip and end planes. It is a positive displacement compressor with no internal compression ratio, two compression cycles per rotation, and positive sealing design attributes. Features include tolerance of liquid flood back, only one moving assembly and no axial loads.

Torad Engineering claims that its 6th generation spool compressor prototype has achieved 80% overall isentropic efficiency which equates to an estimated EER of 22.7 at the SEER B point.

“I have been working in the compressor industry for almost 30 years. I have been involved in the design, engineering and manufacturing of reciprocating, single screw, twin screw, scroll and turbo compressors with industry leading companies. To make this much progress, as fast as we have, is unimaginable,” said Joe Orosz. “It will be interesting to see how far this technology can go. We are still very early in the development cycle and already see outstanding operating characteristics and scaling potential.”

“It has been widely accepted that in production, the spool compressor will have a very competitive price structure,” added Greg Kemp. “Now that Torad has reached this efficiency milestone, system builders and compressor OEMs are showing great interest in the spool compressor as an alternative to legacy compressors, such as the scroll and screw. Torad’s greatest challenge now is identifying companies that have the resources and courage to innovate in a mature market.

“Our next step is to partner with market leading OEMs that are ready to change the industry,” added Greg Kemp. These discussions are going well. We expect to be announcing new partnerships over the next several quarters.”