Joule-Thomson effect
Throttling temperature change
The Joule-Thomson effect is the temperature change that occurs when a gas expands through a valve or porous plug without exchanging heat with its surroundings.
Most gases cool when they expand this way, which is the principle behind refrigeration and air conditioning.
Some gases, like hydrogen and helium at room temperature, warm instead.
The effect is named for physicists James Joule and William Thomson (Lord Kelvin), who described it in the 1850s.
- throttlingRestricting flow or speed
- enthalpyThermodynamic total heat quantity
- liquefactionConversion to liquid state
- thermodynamicsScience of heat-energy relationships
- cryogenicsUltralow temperature science
Dewar flask · ideal gas · temperature · inversion · porous · temperature change · cooling · cold spot · expansion · gas · pressure differential · gas laws · pressure · pressure drop · refrigeration · chilling · nozzle · flow
- gasesgas, air, oxygen, helium, nitrogen
- coolingair conditioning, refrigeration, air cooler, heat sink, evaporator
- refrigerationcompressor, refrigerator, refrigerant, condenser, refrigerants
- thermodynamicsentropy, enthalpy, heat transfer, free energy, heat capacity