Apparatus and method of utilizing thermal energy using multi fluid direct contact hydraulic cycles

An apparatus for extracting useful work or electricity from low grade thermal sources comprising:

• a chamber;
• a source of heated dense heat transfer fluid in communication with a heat transfer fluid conduit that is in communication with the chamber;
• a source of motive fluid in communication with a motive fluid conduit that is in communication with the chamber, wherein the motive fluid comprises a liquid phase;
• a flow control mechanism comprising:
• a heat transfer fluid pump to provide a flow of the heat transfer fluid to the chamber;
• a heat transfer fluid valve cooperating with the heat transfer fluid conduit to control the flow of the heat transfer fluid to the chamber;
• a motive fluid pump to provide a flow of the motive fluid to the chamber;
• and
• a motive fluid valve cooperating with the motive fluid conduit to control the flow of the motive fluid into the chamber;
• wherein the flow control mechanism cooperates with the source of heated dense heat transfer fluid and with the source of motive fluid to deliver said fluids into the chamber in a manner that said fluids come into direct contact with each other in the chamber to effect a phase change of the motive fluid from liquid to gas to increase the pressure within the chamber to yield pressurized fluids, wherein the heat transfer fluid and the motive fluid do not dissolve into each other;
• and
• a work extracting mechanism in communication with the chamber that extracts work from the pressurized fluids by way of pressure let down.