 Thermally isolated system

A thermally isolated system is a physical system that does not exchange heat with its surroundings. This means that the system is insulated in such a way that any thermal energy (heat) generated or absorbed within the system does not enter or leave the system. In thermodynamics, a thermally isolated system is often assumed to help simplify analysis and calculations, particularly when applying the first law of thermodynamics (the law of conservation of energy).