NIST Publication on Inefficient Cryocooler Compression

NIST Publications

Published March 10th, 2026

Detected March 11th, 2026

Summary

NIST published a study on March 10, 2026, detailing inefficiencies in low-frequency cryocoolers used in scientific research. The publication highlights that the compression process is a major source of energy loss, suggesting potential for significant electricity savings with improved compressor technology.

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What changed

NIST has published a research paper on March 10, 2026, concerning the inefficiencies of low-frequency cryocoolers, which are essential for achieving millikelvin temperatures in scientific applications like quantum information processing. The study, authored by Snodgrass, Kotsubo, Hoehne, and Ullom, combines theoretical calculations with experimental data to show that the electrical power consumed by the compressor is converted to acoustic power at a low rate of 0.24, with transmission efficiency at 0.66. This indicates that the compression stage is the primary bottleneck for system efficiency.

While this publication is a research finding and not a regulatory mandate, it has implications for manufacturers and researchers in the field of cryogenics. The findings suggest that advancements in compressor technology, such as the metal-bellows compressor tested, could potentially reduce electricity consumption by two to three times. Compliance officers in research institutions or companies involved in developing or utilizing such equipment should be aware of these findings for potential future technology adoption or efficiency improvements.

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PUBLICATIONS

Low-frequency cryocoolers are compressed inefficiently

Published

March 10, 2026

Author(s)

Ryan Snodgrass, Vincent Kotsubo, Jens Hoehne, Joel Ullom

Abstract

Millikelvin refrigerators are enabling tools for many fields of modern science, including quantum information processing. They are typically precooled to 4 K by low-frequency pulse-tube refrigerators, which perform a thermodynamic cycle based on compressing and expanding helium gas. Although the efficiency of these refrigerators is known to be poor, only the loss mechanisms that occur near the cold end have been sufficiently studied and characterized. Here, we combine thermoacoustic calculations with measurements from a commercial pulse-tube refrigerator to determine the efficiency of the generation and transmission of acoustic power, which the refrigerator uses to provide cooling. We find that electrical power consumed by the compressor is converted to acoustic power at a rate of only 0.24, while acoustic power is transmitted through the refrigerator at a comparatively high efficiency of 0.66. The compression process therefore dominates the portion of the system efficiency that is not limited by fluid and material properties. To show that more efficient compression is possible, we also performed measurements on a new metal-bellows compressor that converts electricity to acoustic power at factors up to 0.43. Our results show that low temperatures may be achievable with two or perhaps even three times less electricity. Citation Physical Review Applied Volume 25 Issue 3 Pub Type Journals

Download Paper

https://doi.org/10.1103/jcb9-j97v Local Download

Keywords

Efficiency, exergy, cryocooler, pulse tube refrigerator, cryogenics, compressor, helium Thermodynamics and Quantum information science

Citation

Snodgrass, R.
, Kotsubo, V.
, Hoehne, J.
and Ullom, J.

(2026),
Low-frequency cryocoolers are compressed inefficiently, Physical Review Applied, [online], https://doi.org/10.1103/jcb9-j97v, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=960142       
  (Accessed March 11, 2026)