Patent ID: 8276384

Claim:
An ambient temperature thermal energy and constant pressure cryogenic engine, comprising: a cryogenic fluid reservoir (A) configured to hold a cryogenic work fluid in a liquid phase (A 2 ), the cryogenic fluid reservoir (A) comprising a fluid heat exchanger (A 3 ) for liquefaction of the fluid into the liquid phase, the cryogenic fluid is a gaseous state being a work gas; a gas compressor (B) to compress a vaporized phase of the fluid into the liquid phase of the fluid; a first duct (A 4 ) connecting the cryogenic fluid reservoir (A) to an inlet of the gas compressor (B); a constant pressure expansion tank ( 19 ), an exhaust of the compressor (B) being fed to the constant pressure expansion tank ( 19 ); an volumetric relief device (D) with an active chamber, the constant pressure expansion tank ( 19 ) connected to an inlet of the volumetric relief device (D), the active chamber (D) comprised of a drive piston ( 1 ), the drive piston sliding in a cylinder ( 2 ) and controlled by a pressure lever, the cylinder having an exhaust duct ( 23 ), the active chamber (D) defining a variable volume producing work, the variable volume coupled, and in permanent contact via a passage, with a space lying above the drive piston so that i) with the space lying above the drive piston at a smallest volume and under thrust of the work gas, the space will increase in volume while producing work, and ii) when the space is at a largest volume, the work gas expands in the engine cylinder thereby pushing back the drive piston in a downstroke while producing work in turn and thereby undergoing a reduction of temperature; and a cryogenic machine (E) for cooling the fluid before the liquefaction of the fluid by the heat exchanger (A 3 ) in the fluid reservoir (A), the exhaust duct ( 23 ) connecting the cylinder ( 2 ) to the cryogenic machine (E), wherein, in a thermodynamic cycle in the fluid storage reservoir (A) the liquid phase of the fluid is vaporized, substantially at a vaporization temperature of the fluid, and the vaporized fluid is supplied to the inlet (A 4 ) of the gas compression volumetric device (B), the gas compressor compressing the vaporized gas to a work pressure to form a compressed work gas at an outlet of the gas compress (B), the compressed work gas is discharged into the expansion tank ( 19 ) at the work pressure and taken, by heat exchange with atmosphere, substantially to ambient temperature, such that, under effect of transfer of thermal energy from the ambient temperature, the temperature of the compressed gas increases and the compressed gas volume increases in same proportions according to a constant pressure relation: V1/V2=T1/T2 so that with said gas still compressed at the work pressure and still substantially at the ambient temperature is let into the volumetric relief device, the work gas, on being exhausted from the exhaust duct ( 23 ) of the said volumetric relief device, is discharged towards the storage reservoir (A) to be liquefied in order to recommence a new thermodynamic cycle.