Abstract: A sensor assembly is shown for sensing a crossing of the critical point in a system utilising a working fluid in a transcritical cycle passing through the critical point. A first broadband acoustic sensor is located upstream of a component and a second broadband acoustic sensor is located downstream of the component, each of which are arranged to detect high-frequency and low-frequency sounds caused by the crossing of the critical point. A flow regulation device regulates flow of working fluid through the component in response to the output of one or both of the first broadband acoustic sensor and the second broadband acoustic sensor, thereby adjusting the location of the crossing of the critical point.

Abstract: A trans-critical thermodynamic system includes an expansion device and a separator. The expansion device receives a supercritical fluid containing solutes. The expansion device is operable to expand the supercritical fluid to produce a sub-critical gas by reducing a temperature and/or a pressure of the supercritical fluid. The separator removes the solutes from the sub-critical gas.

Abstract: A turbomachine (105) configured to compress supercritical carbon dioxide is shown. The turbomachine comprises, in fluid flow series, an inlet (201), an inducerless radial impeller (202) having a plurality of backswept blades (211,212) each of which have a blade exit angle (?2) of from ?50 to ?70 degrees, and a fully vaneless diffuser (203).

Abstract: A turbomachine (105) configured to compress supercritical carbon dioxide is shown. The turbomachine comprises, in fluid flow series, an inlet (201), an inducerless radial impeller (202) having a plurality of blades, and a fully vaneless diffuser (203).

Abstract: A turbomachine (105) configured to compress supercritical carbon dioxide is shown. The turbomachine comprises, in fluid flow series, an inlet (201), an inducerless radial impeller (202) having a plurality of blades, and a fully vaneless diffuser (203). The inlet is radially flared to induce a radial component in flow prior to an entry to the impeller.

Abstract: A turbomachine (105) configured to compress supercritical carbon dioxide is shown. The turbomachine comprises, in fluid flow series, an inlet (201), an inducerless radial impeller (202) having a plurality of blades, and a fully vaneless diffuser (203). The radius of the inlet (r0) is from 25 to 50 percent of the radius of the impeller (r2).