Methods and systems of power generation that integrate SCO.sub.2 Brayton and Rankin steam power cycles with fossil fuel combustion, One such method involves combusting a fuel material with an oxidizer material in a combustor to produce heat and a combustion exhaust. At least a portion of the combustion exhaust and a first portion of heat produced by the combustion processing are fed to a SCO.sub.2 Brayton power cycle to produce power and a second exhaust. At least a portion of the second exhaust and a second portion of heat produced by the combustion processing are feed to a steam Rankine power cycle to produce additional power and a third exhaust.

Processes for controlling the flowrate of and recovering energy from a gas stream in a processing unit are described. One process comprises directing a portion of the gas stream through one or more variable-resistance power-recovery turbines to control the flowrate of the gas stream and generate electric power therefrom; and controlling the pressure and temperature of the gas stream so that the gas exiting the power-recovery turbine remains in the gas phase.

Processes for controlling the flowrate of and recovering energy from a gas stream in a processing unit are described. One process comprises directing a portion of the gas stream through one or more variable-resistance power-recovery turbines to control the flowrate of the gas stream and generate electric power therefrom; and controlling the pressure and temperature of the gas stream so that the gas exiting the power-recovery turbine remains in the gas phase.

Systems, apparatus, and methods described herein can overcome some of the disadvantages associated with existing internal combustion engines. In particular, systems, apparatus, and methods described herein relate to improving the combustion process of internal combustion engines through insert technologies, engine modifications, control technologies, and/or other methodologies.

A combined cooling, heating and power system is formed by integrating a CO.sub.2 and ORC cycle systems, and an LNG cold energy utilization system on the basis of an SOFC/GT hybrid power generation system. The combined systems provide utilization of energy and low carbon dioxide emission. The SOFC/GT is used as a prime mover, high-temperature, medium-temperature, and low-temperature waste heat of the system are recovered through a CO.sub.2 and ORC cycles, cold energy (for air conditioning and refrigeration), heat, power, natural gas, ice, and dry ice is provided by using LNG as a cold source of the CO.sub.2 cycle and the ORC cycle, and low carbon dioxide emission of the system is achieved by condensation and separation of CO.sub.2 from flue gas, so energy losses of the combined system is reduced, and efficient and cascade utilization of energy is achieved, thereby providing energy conservation and emission reduction effect.

An exhaust gas treatment device, an aircraft propulsion system and method for treating an exhaust gas stream are provided. The exhaust gas treatment has a condenser, which condenses at least a portion of water contained in the exhaust gas stream from the turbomachine and thereby releases a first energy; an evaporator, which evaporates at least a portion of the water condensed in the condenser and thereby absorbs a second energy, which is extracted from the exhaust gas stream from the turbomachine; a turbine, which is driven by steam output by the evaporator and expands the steam; a fan, which can be driven by the turbine and feeds the condenser ambient air in order that it absorb the first energy; and at least one exhaust apparatus, out of which the ambient air given off by the condenser and/or a dehumidified exhaust gas stream is exhausted from the condenser.

Processes for controlling the flowrate of and recovering energy from a gas stream in a processing unit are described. One process comprises directing a portion of the gas stream through one or more variable-resistance power-recovery turbines to control the flowrate of the gas stream and generate electric power therefrom; and controlling the pressure and temperature of the gas stream so that the gas exiting the power-recovery turbine remains in the gas phase.

Processes for controlling the flowrate of and recovering energy from a gas stream in a processing unit are described. One process comprises directing a portion of the gas stream through one or more variable-resistance power-recovery turbines to control the flowrate of the gas stream and generate electric power therefrom; and controlling the pressure and temperature of the gas stream so that the gas exiting the power-recovery turbine remains in the gas phase.

An apparatus configured to cool an electronic assembly includes an evaporator configured to evaporate a cooling medium using heat of the electronic assembly, and a power transformer configured to transform energy stored in the evaporated cooling medium into electric power. The cooling medium has an evaporating temperature at atmospheric pressure within a temperature range of 50 C. to 80 C.

An apparatus configured to cool an electronic assembly includes an evaporator configured to evaporate a cooling medium using heat of the electronic assembly, and a power transformer configured to transform energy stored in the evaporated cooling medium into electric power. The cooling medium has an evaporating temperature at atmospheric pressure within a temperature range of 50 C. to 80 C.