Simultaneous compressor-expander

A simultaneous compressor-expander for simultaneously compressing a first working fluid in a gaseous phase and decompressing a second working fluid in a liquid phase, the simultaneous compressor-expander comprising:

• a first liquid ring compressor and a second liquid ring compressor, each of the first and second liquid ring compressors comprising:
• a respective first end wall at a respective first end thereof;
• a respective second end wall at a respective second end thereof, the respective second end opposite the respective first end;
• a respective outer wall extending from the respective first end to the respective second end, the respective outer wall configured to be rotationally symmetric about a respective chamber axis;
• a respective chamber defined by the respective first end wall, the respective second end wall and the respective outer wall, the respective chamber having:
• a respective gas inlet;
• a respective gas outlet;
• a respective liquid inlet;
• and
• a respective liquid outlet;
• and
• a respective set of vanes disposed within the respective chamber, the respective set of vanes configured to rotate about a respective vane axis parallel to, and spaced from, the respective chamber axis,
• wherein each respective liquid ring compressor is configured to form a respective liquid ring from a second working fluid moving between the respective liquid inlet and the respective liquid outlet, and to compress a first working fluid in a gaseous phase from the respective gas inlet to the respective gas outlet;
• a gas connection between the respective gas outlet of the first liquid ring compressor and the respective gas inlet of the second liquid ring compressor, such that the first working fluid is moved, in use, through the first liquid ring compressor and the second liquid ring compressor in series;
• and
• a liquid connection between the respective liquid outlet of the second liquid ring compressor and the respective liquid inlet of the first liquid ring compressor, the liquid connection comprising a flow regulator configured to permit a substantially unidirectional flow of the second working fluid, in use, from the second liquid ring compressor to the first liquid ring compressor.