[Encyclios]

Adiabatic transformation

An adiabatic transformation is a type of thermodynamic transformation characterized by the fact that the system does not exchange heat with the environment: this means that \(Q_{1,2} = 0\) and therefore that the first principle of thermodynamics assumes the formulation \(\Delta U_{1,2} = W_{1,2}\). According to this relation, the mechanical energy supplied (or subtracted) to the system, in an adiabatic transformation, is entirely found as an increase (or decrease) of internal energy of the system itself.

A quasi-static adiabatic transformation is also representable in the Clapeyron plane, however, its course depends strictly on the equation of state of the system. Physically, an adiabatic transformation can be considered realized in a system bounded by walls that are perfect insulators.