Joule-Thomson Refrigeration

Sam Coogan

Adiabatic Expansion

• Many ways to have adiabatic expansion– Constant Entropy

(Isentropic)– Constant Internal Energy

(Free Expansion)– Constant Enthalpy

(Joule-Thomson)

Joule-Thomson Effect

• Throttling process reduces pressure• Caused by non-idealities• Joule-Thomson Coefficient

Why?

• Cooling at very low temperatures• Achievable Cryogenics• Short cool down time

Applications

• Cryogenic Freezing (Cryonics)• Gas liquefaction (O2, N2, Ar)• Linde Technique (Liquefaction of Air)

Sources

• http://www.aero.org• http://www.thales-cryogenics.com• http://www.wikipedia.org• www.cryogenicsinternational.com