Pochari Technologies has devised a novel form of iso-thermal piston compressor.
A dense pattern of relatively thin wall cooling tubes extend out and fasten to the compressor cylinder head, the cooling tubes feature an internal passageway for high heat capacity coolants. The pressure of the liquid medium is set at close to the compressor’s operating pressure to minimize the thickness of the cooling tubes. The piston’s compressor features internal bores to accommodate the space of these cooling tubes. A small gap is left as to prevent any friction between the piston’s female bores and the cooling tubes. As the piston reaches the top of the cylinder assembly, the gas is squared tightly between the female bores and the male cooling tubes, allowing extremely rapid heat transfer into the cooling medium.
Even with the high density cooling tubes, there is sufficient space on the cylinder head for gas exit, since the density of the compressed gas is so much greater than during the inlet stroke, the valves can be quite small. During the intake stroke, a wall-valve similar to a two-stroke is used, or a long residence time can be used. A series of small valves are placed at the top of the cylinder assembly between the extending cooling tubes. In the piston assembly, it would be possible to also accommodate small cooling channels in the space between the female bores. To minimizes the thickness of the metal, it would be desirable to also keep the pressure of the coolant as high as possible. Higher pressure also raises the boiling point of the liquid cooling medium. Water has a boiling point of 375 degrees Celsius at 225 bar, this forms the working principle of the famous pressurized water reactor.
With this iso-thermal compression concept, it would be possible to achieve a complete atmospheric to ammonia-synthesis ready 300 bar in a single compression stroke, massively improving the flow capacity and productivity of a single compressor. Due to the fact that the surface area of the cooling tubes is quite high due to their spacing count and relative small size, the total potential thermal flux is immense. The limiting factor would not be metal surfaces, but the cooling medium which would have to be pumped at a high enough flow rate to purge the heat from the gas compression.