Abstract: A heat exchanger comprising a pressure vessel (1). A plurality of serpentines (8) convey a fluid to be heated through the pressure vessel (1) in one direction. A duct (9) surrounding the serpentines (8) conveys a second fluid in the opposite direction to give up its heat to the first fluid. The duct (9) is spaced from the pressure vessel (1) and is surrounded with thermal insulation (23). An opening in the duct (9) equalizes the pressure between the inside and the outside of the duct (9) which is also supported against expansion caused by the pressure inside the duct (9) exceeding the pressure outside the duct (9).

Abstract: A compressor comprising a cylinder (1) with an axially reciprocating piston (5) which compresses gas in the cylinder. At least two circumferential rows of flat fan spray nozzles (10) spray water into the cylinder during compression. Each nozzle is arranged such that the spray is in a plane substantially parallel to the axis (4) of the cylinder and is directed towards a central region of the cylinder.

Abstract: A reciprocating gas compressor in which a piston (3) reciprocates within a compression chamber (1) in order to compress gas. Water is injected through nozzle (6, 7) into the compression chamber to cool the gas during compression. A source of pressurised liquid (13) is arranged to accelerate liquid through the nozzle (6, 7). At least one duct (14, 17, 19) connects the pressurised source (13) to the nozzles (6, 7). The dimensions of the duct (14, 17, 19) are sized to define the inertia of the liquid to control the acceleration of the mass flow through the nozzles during compression such that the cooling capacity of the liquid in the compression chamber increases as the pressure therein approaches its final value.

Abstract: An engine comprising an isothermal air compressor (1) into which liquid is sprayed as the air is compressed. A combustion chamber (4) receives and expands the compressed air from which the liquid has been removed, to generate power. A precompressor (21, 27) compresses the air upstream of the isothermal compressor. The compressed air from the isothermal compressor receives heat from the exhaust gas from the combustion chamber in a primary heat exchanger (3). A secondary heat exchanger (31, 45) transfers heat recovered from a part of the engine to the compressed air from the isothermal compressor (1) upstream of the primary heat exchanger (3).

Abstract: An internal combustion engine has a compression cylinder with a liquid spray apparatus for spraying sufficient liquid into the cylinder such that the liquid absorbs the heat of the gas as it is compressed without vaporizing. A separator removes the liquid from the gas/liquid mixture as it leaves the cylinder. The gas is then directed to a expansion cylinder for combustion with fuel delivered by a fuel supply apparatus. The cylinders being coupled together by a crankshaft.