Superfluid Joule-Thomson refrigeration, a new concept for cooling below 2 Kelvin

A new type of sub-Kelvin refrigerator, the superfluid Joule-Thomson refrige rator is discussed. The refrigerator uses the circulation of the He-3 compo nent of a liquid He-3-He-4 mixture through a throttle to provide cooling to temperatures of 0.5 K. A simple analytical model is developed to predict t he cooling power for this refrigerator as function of temperature. In addit ion, cooling power predictions are made using the equations of state of Rad ebaugh. The models are compared and discussed. This refrigerator can provid e cooling in a microgravity environment.