Thermodynamic process

A thermodynamic process ( a thermodynamic transformation ) is a change in the thermodynamic state ( change of state). In the case of an equilibrium state, this can only happen with a change in one or more external parameter ( state variable ).

In quasi-static thermodynamic processes ( equilibrium process ), these parameters are changed so slowly that the system at any point in equilibrium ( or arbitrarily close to it) is, ie a sequence of equilibrium states by running ( → infinitesimally small changes of state ).

Quasi-static processes are called reversible (time- reversible ), if they are even reversed by reversing the change of the external parameters. The entropy increases not to. Not everyone quasistatic process is reversible.

Types of thermodynamic processes

Isobaric processes take place at constant pressure. May serve as an example, a movable piston in a cylinder, wherein the pressure within the cylinder is always under atmospheric pressure stops.

Under a Isochoric process is defined as a process that occurs at constant volume. The system does not perform mechanical work in energy intake. When heated. Is a closed system, for example, air in a closed sleeve, is only changed, the internal energy of the gas, that is, that the temperature and the pressure increases

An isothermal process is a process that occurs at a constant temperature. Adiabatic processes are processes at constant energy, ie without for energy supply or dissipation. Reversible adiabatic processes are identical to isentropic processes that take place at constant entropy.

From isenthalps processes occurs when the enthalpy of a system does not change.

Sometimes these processes are summarized under the term Isoprozesse.