A trans-critical thermodynamic system includes an expansion device and a separator. The expansion device receives a supercritical fluid containing solutes. The expansion device is operable to expand the supercritical fluid to produce a sub-critical gas by reducing a temperature and/or a pressure of the supercritical fluid. The separator removes the solutes from the sub-critical gas.

A combined cooling, heating and power system is formed by integrating a CO.sub.2 cycle subsystem, an ORC cycle subsystem, and an LNG cold energy utilization subsystem based on an SOFC/GT hybrid power generation subsystem. The combined system can achieve efficient and cascade utilization of energy and low carbon dioxide emission. An SOFC/GT hybrid system is used as a prime mover. High-, medium-, and low-temperature waste heat of the system are recovered through CO.sub.2 and ORC cycles, respectively. Cold energy (for air conditioning and refrigeration), heat, power, natural gas, ice, and dry ice can be provided by using LNG as a cold source of the CO.sub.2 and ORC cycles. Low CO.sub.2 emission is achieved by condensation and separation of CO.sub.2 from flue gas, so energy loss of the system can be reduced, and efficient and cascade utilization of energy can be achieved, thereby realizing energy conservation and emission reduction.

Gas turbine engines are described. The gas turbine engines include a compressor section, a combustor section, a turbine section, a nozzle section, wherein the compressor section, the combustor section, the turbine section, and the nozzle section define a core flow path that expels through the nozzle section, and a waste heat recovery system. The waste heat recovery system includes a heat recovery heat exchanger arranged at the nozzle section, wherein the heat recovery heat exchanger is arranged within the nozzle section such that the heat recovery heat exchanger occupies less than an entire area of an exhaust area of the nozzle section and a heat rejection heat exchanger arranged to reduce a temperature of a working fluid of the waste heat recovery system.

A supercritical hydrothermal combustion device comprises a main enclosure and a top cap. A partition is mounted in the main enclosure and divides the interior of the main enclosure into a main combustion space and a mixing space. The top cap is provided with a primary fuel inlet, an oxidant inlet and a secondary fuel inlet. A high-temperature ignition bar sleeve, having a high-temperature ignition bar arranged therein, is disposed in the top cap. A combustion sleeve, having a stable combustion space formed therein, is mounted at a bottom of the top cap, and has a top communicated with the high-temperature ignition bar sleeve and the oxidant inlet, as well as a bottom communicated with the main combustion space. The secondary fuel inlet and a secondary oxidant inlet are communicated with the main combustion space. Supercritical hydrothermal combustion is realized to generate a hybrid thermal fluid or treat organic wastes.

A supercritical hydrothermal combustion device comprises a main enclosure and a top cap. A partition is mounted in the main enclosure and divides the interior of the main enclosure into a main combustion space and a mixing space. The top cap is provided with a primary fuel inlet, an oxidant inlet and a secondary fuel inlet. A high-temperature ignition bar sleeve, having a high-temperature ignition bar arranged therein, is disposed in the top cap. A combustion sleeve, having a stable combustion space formed therein, is mounted at a bottom of the top cap, and has a top communicated with the high-temperature ignition bar sleeve and the oxidant inlet, as well as a bottom communicated with the main combustion space. The secondary fuel inlet and a secondary oxidant inlet are communicated with the main combustion space. Supercritical hydrothermal combustion is realized to generate a hybrid thermal fluid or treat organic wastes.

Methods for thermalsiphoning supercritical CO.sub.2 within a geothermal formation includes providing a geothermal energy system that includes an underground hot rock reservoir, a production well, and an injection well that together form a fluid path suitable for circulating supercritical CO.sub.2. The supercritical CO.sub.2 flows by thermosiphoning. Thermosiphoning is maximized by maintaining a pressure between 1400-4000 psia, an injection temperature in a range from 50-200 C and a production temperature in a range from 150-600 where injection temperature and the production temperature differ by at least 50° C.

Various technologies pertaining to tuning composition of a fluid mixture in a supercritical Brayton cycle power generation system are described herein. Compounds, such as Alkanes, are selectively added or removed from an operating fluid of the supercritical Brayton cycle power generation system to cause the critical temperature of the fluid to move up or down, depending upon environmental conditions. As efficiency of the supercritical Brayton cycle power generation system is substantially optimized when heat is rejected near the critical temperature of the fluid, dynamically modifying the critical temperature of the fluid based upon sensed environmental conditions improves efficiency of such a system.

Various technologies pertaining to tuning composition of a fluid mixture in a supercritical Brayton cycle power generation system are described herein. Compounds, such as Alkanes, are selectively added or removed from an operating fluid of the supercritical Brayton cycle power generation system to cause the critical temperature of the fluid to move up or down, depending upon environmental conditions. As efficiency of the supercritical Brayton cycle power generation system is substantially optimized when heat is rejected near the critical temperature of the fluid, dynamically modifying the critical temperature of the fluid based upon sensed environmental conditions improves efficiency of such a system.

Gas turbine engines are described. The gas turbine engines includes a compressor section, a combustor section, a turbine section, and a nozzle section. The compressor section, the combustor section, the turbine section, and the nozzle section define a core flow path that expels through the nozzle section. A cooling duct is provided that is separate from the core flow path. A waste heat recovery system is arranged with a heat rejection heat exchanger arranged within the cooling duct and a blower is arranged within the cooling duct and configured to generate a pressure drop across the heat rejection heat exchanger.

A process for regasifying a fluid and generating electrical energy includes subjecting an operating fluid to 1) pumping, the pumping step including a low pressure pumping step 1a) and a high pressure pumping step 1b), 2) heating in a recuperator to obtain a heated flow, the heating step including a low temperature heat recovery step 2a) and a high temperature heat recovery step 2b), 3) further heating through a high temperature source to obtain a further heated flow, 4) expanding in a turbine, with generation of electrical energy to obtain an expanded flow, 5) cooling by heat exchange to obtain a cooled flow, and 6) condensing the flow of the operating fluid and regasifying the fluid. After low pressure pumping, a portion of the flow of the operating fluid is subjected to recompression to obtain a flow combined with the flow of the operating fluid obtained from step 2a).