CO2 isn’t a liquid at normal room temperature and pressure. It is a gas.
In this graph from The Engineering ToolBox, the equilibrium curve is the colored one between the triple point and the critical point.
The Triple Point is the only point in which CO2 exists in a solid, liquid and gaseous phase at the same time, due the specific combination of temperature and pressure. The Critical Point is characterized by the disappearance of the difference between gaseous phase and liquid phase.
When temperature and pressure are increased over the critical point, we have supercritical fluid. The CO2 is at the same time a liquid and a gas at every point along the Equilibrium Curve.
Maintaining the CO2 along this curve will save a lot of energy. Our system is designed to maintain this equilibrium in the reservoir, one of the most important vessels in the system. Without a good control of temperature and pressure at the reservoir’s level, you’ll never be able to have a stable flow in the system.
In our system it’s easy to set the pressure in the reservoir at the desired value. We suggest 48 bar. The system, thanks to our full adaptive automation control, will stabilize the pressure automatically.