Two-phase heat engine

A method for producing work, comprising the steps of:

• heating a heat transfer liquid (HTL) to a first temperature within a heating volume and delivering said HTL to an inlet of a nozzle at about a first pressure, wherein the nozzle is part of a reaction turbine;
• compressing gas by a compressor to about said first pressure and heating isobarically or quasi-isobarically the compressed gas within a heat receiving portion of a heat exchanger to about said first temperature or lower than about said first temperature;
• mixing in said nozzle said HTL at said first pressure and said first temperature with the compressed gas at about said first pressure and about said first temperature or lower than about said first temperature to obtain a gas and HTL mixture, wherein the gas and the HTL in the mixture reaches to about the same temperature after said mixing;
• allowing the gas in the mixture to undergo isothermal or quasi-isothermal expansion within said nozzle to a second pressure lower than said first pressure, thereby causing acceleration of said mixture towards an outlet of said nozzle;
• ejecting said mixture of gas and HTL through said outlet to produce mechanical work and separating the HTL from the gas following said ejecting;
• introducing the ejected gas into a heat removal portion of said heat exchanger to exchange heat with compressed gas exits said compressor;
• and
• directing at least a portion of the ejected HTL towards said heating volume.

A method for realizing a heat engine, comprising the steps of:

• introducing heat transfer liquid (HTL) into a nozzle at a first pressure and first temperature, wherein the nozzle is part of a reaction turbine;
• isothermally compressing gas by a compressor from second pressure and second temperature to said first pressure, wherein said second pressure and temperature are lower than said first pressure and first temperature, respectively;
• isobarically or quasi-isobarically heating the compressed gas, exiting the isothermal compressor at a first pressure and a second temperature, by passing it via a heat receiving portion of a counter flow heat exchanger to about said first temperature;
• injecting the heated gas exiting the heat receiving portion of said heat exchanger into said nozzle to obtain a HTL and gas mixture, thereby causing the mixture to expand isothermally or quasi-isothermally to said second pressure, resulting in acceleration of the mixture in the nozzle;
• and
• ejecting the accelerated mixture of gas and HTL from an outlet of the nozzle and separating the HTL from the gas following said ejecting;
• retrieving the ejected gas at about a second pressure and about a first temperature to a heat removal portion of the heat exchanger for exchanging heat to new compressed gas exiting from the compressor.

A system for producing work, comprising the steps of:

• a heating volume for allowing heating heat transfer liquid (HTL) to a first temperature by a heat source;
• a pump for raising pressure of said HTL to a first pressure at said first temperature;
• a compressor configured to compress gas to about said first pressure;
• a heat exchanger in fluid communication with the compressor and configured to receive the compressed gas into a heat receiving portion thereof to allow transfer of heat to the compressed gas to increase its temperature isobarically or quasi-isobarically to about said first temperature or lower than about said first temperature;
• a nozzle in fluid communication with the heat exchanger and the HTL pump having an inlet portion for receiving said HTL and a mixing portion for (i) allowing mixing said HTL at about said first temperature and at about said first pressure with said gas at about said first temperature or lower than about said first temperature and about said first pressure to obtain a mixture and (ii) allowing said mixture to undergo isothermal expansion to a second pressure lower than said first pressure, thereby causing acceleration of said mixture at said nozzle towards an outlet of the nozzle;
• a reaction turbine configured for rotation in result to the acceleration of said mixture, thereby converting the kinetic energy of the mixture to work;
• a separation unit for separating the HTL and the gas, said separation unit comprises a collection unit to collect the ejected HTL and to allow to direct it to either the heating volume, the pump or to the nozzle or towards the nozzle and one of the heating volume or the pump;
• wherein the separated ejected gas is transferred to a heat removal portion of the heat exchanger to exchange heat with new compressed gas in the heat receiving portion that flows from the compressor.