Process for converting the internal energy of liquid CO.sub.2 into mechanical energy capable of producing work as it changes from liquid to gas over its critical temperature

Process for converting the internal energy of a fluid into mechanical energy capable of producing work, based on the use of the fluid having two alternative states, liquid and gaseous, at temperatures below and above its critical temperature, said critical temperature being higher than but close to normal ambient temperature, essentially characterized in that it comprises several operative steps:

• liquefying the fluid at a temperature and a pressure below the critical temperature and critical pressure thereof;
• introducing the liquefied fluid into a chamber provided with means for transmitting movement and means for transmitting heat;
• pressurizing the fluid to a pressure at or above the critical pressure prior to heating;
• subjecting the liquefied fluid to a rapid heating, whereby the critical temperature is exceeded, the pressure is considerably increased, and the fluid is immediately converted to the gaseous state;
• expanding the gasified fluid rapidly in the interior of the chamber against resistence offered by the means for transmitting movement to produce work;
• and
• recovering and returning the fluid to the initial conditions below the critical temperature and critical pressure.