System models of thermodynamics

                   Thermodynamic system is a precisely specified macroscopic region of the universe, defined by boundaries or walls of particular natures, together with the physical surroundings of that region, which determine processes that are allowed to affect the interior of the region, studied using the principles of thermodynamics.
                   The universe outside  system is known as the surroundings,  environment, or reservoir. A system is separated from its surroundings by a boundary, which may be notional or real but by convention, delimits a finite volume. Transfers of work, heat, or matter and energy between the system and the surroundings may take  across this boundary. A thermodynamic system is classified by the nature of the transfers that are allowed to occur across its boundary, or parts of its boundary.
                                       System models of thermodynamics  
 

isolated system

An isolated system has only isolating boundary sectors. Nothing can be transferred into or out of boundary.

closed system

 A closed system has no boundary sector that is permeable to matter, but in general its boundary is permeable to energy. For closed systems, boundaries are totally prohibitive of matter transfer.

opened system

An open system has a boundary sector that is permeable to matter; such a sector is usually permeable also to energy, but the energy that passes cannot in general be uniquely sorted into heat and work components. Open system boundaries may be either actually restrictive, or else non-restrictive.