"Transcritical" Meaning Thermodynamics

Having an interest in refrigeration in general I’ve sort of wondered how R-744, carbon dioxide works in more detail since it’s going to end up being a supercritical fluid in at least part of the cycle.

Turns out this is described as a “transcritical cycle” and I’m just really pleased to be seeing “transcritical” meaning something thermodynamic rather than an attack on human rights, happiness, and flourishing!

So anyway the carbon dioxide ends up above the critical temperature and pressure and rejects heat as a supercritical fluid before being brought down below the critical pressure and turned into a liquid and gas mix, the liquid sent to the evaporator(s) for cooling and the gas passing directly back to the compressor.