Real gas effects on the temperature profile of regenerators

• Real gas effects influence the temperature profile of regenerators at around 4 K.
• The thermal conduction is found to be a minor role in shaping the profile.
• The heat-associated enthalpy flow is proved to be the major role in practical cases.
• Methods for improving the refrigeration efficiency are further discussed.

Real gas properties impose profound effects on regenerators. The enthalpy flow associated with the pressure dependence, abbreviated as the pressure-induced enthalpy flow, generally affects the temperature profile of regenerators and makes it far from linear at temperatures close to and below the critical point. This phenomenon has attracted great interest for a long time. In this paper, the factors in shaping the temperature profile are investigated. Different from previous studies, our analysis has revealed that the enthalpy flow associated with imperfect heat transfer and limited matrix heat capacity in the regenerator, abbreviated as the heat-associated enthalpy flow, together with the pressure-induced enthalpy flow plays the main role in shaping the temperature profile. This identification suggests a starting point for further investigation into the working mechanism at liquid-helium temperatures, and also for improvement of refrigeration efficiency in this temperature range.