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Spool compressor achieves EER of 12 on R1234ze

USA: The company behind the development of a new design of compressor for chillers, air conditioners and heat pumps claims to have exceeded an EER of 12 using R1234ze. 

Tests on the latest generation of spool compressor being developed by Torad Engineering of Cumming, Georgia, are said to have recorded a system EER of 12.3 and COP of 3.61 when running on R1234ze.  An EER of 12 is seen as an efficiency milestone necessary for cost effective adoption of low and ultra-low GWP HFO refrigerants in light commercial chiller and heat pump applications. This includes refrigerants such as R513A and HFO1234ze.

The spool compressor resembles a rotary vane compressor, but is described as being smaller, lighter and cheaper to manufacture than current technology. It has just four main components: rotor, main housing, vane, and bearing housing.

The latest results follow two years of work by Torad to advance its spool compressor technology to specifically address HFO refrigerant efficiency requirements. The company has used comprehensive numeric modelling, computational fluid dynamics and rapid prototyping to produce multiple design enhancements and significant efficiency gains. Geometry and discharge valve optimisations are said to have yielded the most substantial improvement in the spool compressor’s overall isentropic efficiency. 

“With the spool compressor’s performance results using ultra-low GWP refrigerants now exceeding industry milestones, Torad intends to move to commercialisation optimised around low/ultra-low GWP refrigerants as soon as possible,” said Torad founder and CEO Greg Kemp.

“The Spool compressor’s performance and inherent cost advantages should facilitate a cost-effective migration to low/ultra-low GWP refrigerants for a broad range of heating and cooling applications,” he added.

An update on the development of the spool compressor will be presented at next month’s International Compressor Engineering Conference at Purdue University.

Related stories:

Spool compressor could offer an R410A-free future8 January 2019
USA: A new design of compressor using refrigerant R1234ze could provide a long-term, low GWP solution for packaged air conditioning and VRF. Read more…

Spool compressor efficiencies hit 80% – 11 July 2016
USA: Latest test results on a prototype 141kW spool compressor are said to have recorded overall isentropic efficiencies approaching 80%. Read more…

Spool compressor passes low GWP test – 14 June 2016
USA: Tests on a 40-ton spool compressor with low GWP refrigerants are said to have demonstrated improved efficiency and performance compared to current compressor designs. Read more…

$2m centre for spool compressor – 20 January 2015
USA: The company behind a new refrigeration and air conditioning compressor design has opened a $2m commercial development centre to support the technology. Read more…

Spool compressor hits peak note – 15 July 2014
USA: The company behind a new refrigeration and air conditioning compressor design claims that its latest prototype has achieved market level energy efficiency. Read more…

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