Optimal absorption of distributed and conductive heat loads with cryocooler regenerators
Ryan Snodgrass, Joel Ullom, Scott Backhaus
The second-stage regenerators of pulse tube refrigerators are routinely used to intercept heat in cryogenic systems; however, optimal methods for heat sinking to the regenerator have not been studied in detail. We investigated intermediate cooling methods by densely instrumenting a commercial, two-stage pulse tube refrigerator with thermometers and heaters. We then experimentally emulated heat loads from common sources such as arrays of electrical cables (a conductive load) and 3He return gas for dilution refrigerators (a distributed load). Optimal methods to absorb these heat loads, whether applied independently or simultaneously, are presented. Our study reveals the importance of understanding the response of the regenerator temperature profile for optimal thermal integration of heat loads along the regenerator, i.e., temperatures and heat flows at all heat sink locations. With optimal utilization of regenerator intermediate cooling, 3He flow rates of up to 2 mmol/s can be cooled from 50 K to 3 K and fully condensed using this pulse tube refrigerator; alternatively, the heat leak from a large number of electrical cables can be cooled across that same temperature span while simultaneously condensing 1.4 mmol/s of 3He.
Advances in Cryogenic Engineering: Proceedings of the Cryogenic Engineering Conference (CEC) 2021
, Ullom, J.
and Backhaus, S.
Optimal absorption of distributed and conductive heat loads with cryocooler regenerators, Advances in Cryogenic Engineering: Proceedings of the Cryogenic Engineering Conference (CEC) 2021, N.A./Remote, CO, US, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933102
(Accessed September 24, 2023)