Reply To: Thermodynamic system

  • Encyclios

    May 10, 2023 at 4:04 PM

    Types of thermodynamic system

    Based on the type and combination of properties of the control surfaces, the following types of thermodynamic system can be distinguished:

    • open system: its boundaries are permeable, albeit partially, to the passage of matter;
    • closed system: it is delimited by boundaries impermeable to the passage of matter; in other words, a closed system cannot exchange matter with the environment, but only energy;
    • isolated system: a system is said to be isolated when, in addition to being closed, it does not exchange energy with the external environment.

    The thermodynamic systems listed above are nothing more than a combination of these properties:

    • open system: porous, mobile, and diathermic;
      • adiabatic open system: porous, movable and adiabatic;
    • closed system: impervious, mobile and diathermic;
      • adiabatic closed system: impervious, movable and adiabatic;
    • isolated system: impervious, rigid and adiabatic.

    It is clear, from these definitions, that a closed system is characterized by the constancy of its mass, while the opposite is not true, in the sense that a system with constant mass is not necessarily closed: in fact, it could also be an open system in permanent regime, that is a system in which, instant by instant, the incoming mass is perfectly equal to the outgoing one.