Spool compressor hits new peak on R1234ze
13th January 2026
USA: Tests on a semi-hermetic spool compressor being developed by Torad have recorded a performance of 72.5% peak overall isentropic efficiency running on R1234ze refrigerant.
The 20TR compressor, tested at the ARI standard condition of 45°F/130°F ((7.2°C/54.4ºC) flange conditions, at 1800 RPM, with power measured at the motor terminals, is said to have achieved an EER of 12.2 and a COP of 3.58. According to Torad, this makes the compressor 4-9% more efficient than any compressor in this size range operating on R1234ze.
“This achievement creates a viable path to commercial HVAC adoption of environmentally sustainable zero-GWP systems without the cost typically associated with next-generation refrigerants,” said Torad president and COO Joe Orosz.
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. It is a positive displacement compressor with no internal compression ratio, two compression cycles per rotation, and positive sealing design attributes.
“The company’s spool compressor technology enables advanced chiller designs improving system efficiency and addressing the current industry trade-off between cost and environmental impact,” Orosz claims.
Torad CEO and founder Greg Kemp revealed that the latest tests received support from Johnson Controls, Solstice, Shrieve, Syensqo, GGB, Clayens and Force Technology.
“We look forward to working with industry partners to bring this technology into commercial production and accelerate the global transition to sustainable cooling solutions.”
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