A diagram showing the concept of a closed system in thermodynamics, able to receive and transmit energy, but with zero mass transfer.
<a href="//commons.wikimedia.org/wiki/User:Ariadacapo" title="User:Ariadacapo">Olivier Cleynen</a>
<span class="int-own-work" lang="en">Own work</span>, part of <a rel="nofollow" class="external text" href="https://thermodynamique.fr/"><i>Thermodynamique de l’ingénieur</i></a>