Patent ID: 8590302

Claim:
A method for heat-exchanging in and work-exchanging with a working fluid in a heat engine, or a heat pump if the method and its sub-processes are reversed, wherein a thermodynamic cycle for the working fluid is approximately described through the polytropic relation PV n =constant, where P is the pressure, V is the volume and n is the polytropic index of the working fluid with adiabatic index gamma (γ), and where the engine has at least one working mechanism provided with a first and at least a second volume change chamber, wherein the method in sequence comprises: a) in a first volume change process, carrying out a first polytropic volume change of the working fluid in a first volume change chamber, where n<γ, and b) in a second volume change process, carrying out at least one second near-adiabatic or polytropic volume change of the working fluid from a first to a second volume change chamber, where n<γ, or where a volume change starts with n<γ and ends near-adiabatic (n≈γ).