Abstract: A method and apparatus for compressing a gas by adiabatic compression and isothermal compression. In a preferred embodiment, the gas is first adiabatically compressed from a first state to a second state and then isothermally compressed to a third final desired state. The disclosed two stage compression allows rejection of the heat generated during isothermal compression at a somewhat elevated temperature so that the radiator or other heat exchanger used to reject this heat may be significantly smaller than would be needed if the gas were isothermally compressed starting from the first state.

Abstract: A method and apparatus are disclosed for minimizing the increase of entropy of an adiabatic enthalpizer by means of a thermal sweep insulation system which surrounds at least a portion of the adiabatic enthalpizer and through which the working fluid for the adiabatic enthalpizer passes whereby the fluid both causes the thermal sweep insulation system to operate and the fluid is pre-enthalpized. Examples of adiabatic enthalpizers include but are not limited to compressors, expanders, devices to heat and expand a gas, Roots blowers, ammonia absorption chambers, etc.

Abstract: A method and apparatus for transferring energy from a first fluid flow to a second fluid flow via vortex generating means. Various embodiments and various support means for elements of the apparatus are also disclosed.