Integrated supercritical CO2/multiple thermal cycles

This disclosure relates to the unique integration of a plurality of thermodynamic cycles comprised of a supercritical carbon dioxide thermodynamic cycle, one or more other thermodynamic cycles with multiple heat sources derived from nuclear fuel, solar energy, hydrogen, and fossil fuels, with the energy production systems configured to noticeably improve power plant efficiency, cost and performance.

FIELD

The present invention relates to using energy discharged from a heat source into a Heat Recovery Unit (HRU) wherein exhaust energy is used and shared by several fluids, at least one of which is a supercritical fluid.

BACKGROUND

The Second Law of Thermodynamic states that thermal efficiency depends on the temperature difference between a heat source and a heat sink. Various thermodynamic cycles have been developed to efficiently convert energy into useful work.

The Rankine closed-system steam cycle has been is use for well over a century. The cycle involves pressurizing water using a plurality of pumps, with heat from an energy source and a plurality of heat exchangers used to increase the temperature of the water, with the heat exchangers typically located within a Heat Recovery Unit (HRU) or boiler. A plurality HRU evaporator heat exchangers boil the water to create steam that is further heated by a plurality of HRU heat exchangers that superheat the steam subsequently directed to a turbine/generator, with the turbine discharging low-pressure steam into a cooler that condenses the water for reuse. The boiling of water requires a considerable amount of energy to evaporate the liquid, thereby causing constraints on the efficient use of energy source's heat. More specifically, the energy required to vaporize (boil) a liquid exceeds that necessary to heat the liquid just short of the commencement vaporization. However, for very hot energy sources, the HRU energy available after vaporization can significantly exceed that necessary to heat the liquid. That is why multiple pressure reheat steam turbines are generally necessary to efficiently use very hot energy sources.

The open-system Brayton combustion turbine cycle has been in use since the 1940s. Air is pressurized by a compressor, fuel added and ignited, with the hot gas used to rotate a turbine that drives the compressor. The turbine can also produce electrical energy by rotating a generator in addition to the compressor.

In the early 1960s, the open-system combustion turbine Brayton air cycle was combined with an HRU that uses the combustion turbine's hot exhaust gas to create steam associated with the Rankine closed-system cycle.FIG. 1illustrates a typical triple-pressure, multiple-reheat steam turbine configuration. Such combined-cycle power plants have become more powerful and efficient as combustion turbine firing temperatures and pressures have steadily increased. However, the ever-higher combustion turbine firing temperatures also increase the temperature of the turbine's exhaust gas entering the HRU. In order to efficiently use the exhaust gas, a plurality of multiple-pressure steam turbines employing reheating of the turbine's discharged steam are necessary. Additionally, the HRU's heat energy can be augmented by fuel fired burners used to further increase exhaust gas temperatures to support additional steam production to meet power grid peaks. The higher HRU temperatures and plurality of reheat steam turbines face material issues, plant control issues, and higher plant capital costs as well as plant reliability problems. The higher firing temperatures of modern combustion turbines are challenging the ability of steam turbines to economically and technically accommodate the increasing steam temperatures caused by higher gas turbine firing temperatures.

Supercritical CO2thermodynamic cycles have been in development for over 50 years. The physical characteristics of supercritical CO2hold the promise of significantly reduced equipment sizes and power plant costs because, unlike cycles employing fluids such as water, boiling of CO2is not a required; the supercritical CO2behaves as neither a distinct vapor nor liquid. Additionally, cooling methods can be employed similar to those used with combustion turbines employing very hot turbine inlet temperatures.FIG. 2illustrates a typical closed-system Brayton supercritical CO2cycle. A Heat Recovery Unit (HRU) employs a heat exchanger to extract heat from the energy source, thereby allowing hot, high pressure supercritical CO2to be used by a turbine/generator. The intermediate pressure exhaust from the turbine is used by a plurality of recuperator heat exchangers to preheat re-pressurized supercritical CO2directed to the HRU; re-pressurization is accomplished by pumps and/or compressors. The recuperators face formidable issues (e.g., effectiveness, high temperature materials and associated costs) owing to the somewhat similar properties of the opposing recuperator supercritical CO2and the need for large scale recuperator energy transfers. In order to efficiently and effectively transfer energy, the recuperators become impractically large. Additionally, pressurization of the supercritical CO2faces formidable equipment design, efficiency and operational problems. Successful commercial deployment of the supercritical CO2cycle power plants remains elusive.

Small nuclear reactors are being developed as a potential means to further nuclear energy. Generally, such reactors rely on utilization of a Rankine closed-system cycle. However, the historical record favors energy production plants that are more efficient and larger than earlier designs, casting doubt on the competitiveness of small reactors that do not possess some forms of economic, technical, and efficiency advantages.

SUMMARY

The disclosure relates to power/energy plants and includes a plurality of heat sources, a plurality of heat recovery units, a plurality of heat exchangers as well as a plurality of recuperators, a plurality of heat exchanger coolers and a plurality of turbines and compressors. The elements of the disclosure are uniquely comprised to allow a plurality of thermal cycles and a Brayton Supercritical CO2cycle to optimally operate while collectively overcoming earlier limitations. The innovation produces more efficient and economic power plants. The energy of the thermodynamic cycles is not limited to particular heat source. Heat sources, including nuclear energy, fossil fuels, hydrogen and solar energy can be used. Combustion turbines using different fuel sources such as gasified coal, natural gas, or hydrogen can be employed. Also, supplemental energy additions to the heat sources can include natural gas, hydrogen and gasified coal, for example. Embodiments of the innovation include nuclear reactors employing a variety of working fluids, including liquids; gases; and fluids containing fissile nuclear materials.

The disclosure's integration of thermal cycles supports power plant efficiency and power output improvements as well as plant simplifications.

DETAILED DESCRIPTION

FIG. 3illustrates a preferred embodiment of the invention in power plant1000. Referring toFIG. 3, the Rankine closed-system cycle200, Brayton closed-system supercritical CO2cycle300and Brayton open-system air cycle100are uniquely integrated. Energy transfer by a plurality of multi-media heat exchangers and recuperator heat exchangers is more efficiently and practically accomplished by sequentially interweaving multi-cycle energy transfers from a plurality of heat sources, including the exhausts associated from the plurality of Brayton open-system air cycle100and Brayton closed-system supercritical CO2cycle300turbines. A plurality of the heat exchanger types allows practical deployment of the Brayton closed-system supercritical CO2cycle300by avoiding the heat transfer complications of earlier approaches. Additionally, pressurization of the CO2is more practically and efficiently accomplished owing to the use of a plurality of electrically motor driven pumps/compressors305used to pressurize a largely CO2fluid to a supercritical state. Relative to earlier approaches employing a plurality of Rankine closed-system cycle200and Brayton closed-system supercritical CO2cycle300turbines, the number of turbines is reduced, simplifying the power plant, enhancing economics and improving power plant efficiency.

Broadly, as illustrated byFIG. 3of power plant1000, energy transfer between a Rankine closed-system cycle200, Brayton closed-system supercritical CO2cycle300and Brayton open-system air cycle100is accomplished using a plurality of heat exchanger and recuperators. A plurality of heat exchangers located in EMU125of the Brayton open-system air cycle100sequentially transfer energy from Brayton open-system air cycle100to both the Brayton closed-system supercritical CO2cycle300and to Rankine closed-system cycle200. A plurality of heat exchangers and recuperators are used to sequentially transfer energy from intermediate pressure supercritical CO2of the Brayton closed-system supercritical CO2cycle300to both the high pressure CO2of the Brayton closed-system supercritical CO2cycle300and the high pressure liquid and vapor of the Rankine closed-system cycle200. The Brayton closed-system supercritical CO2cycle300is efficiently optimized to use the heat source121energy while the Rankine steam cycle200efficiently uses heat source energy121to support the practical capabilities of steam turbines245and265and the Heat Recovery Unit (HRU125). The ability to simultaneously control the pressure and fluid flow of the Rankine closed-system cycle200and control the flow of the Brayton closed-system supercritical CO2cycle300collectively provide net design, operational and efficiency benefits not ordinarily available. These features also provide net operational and control benefits in dealing with the variable flows and temperatures associated with the Brayton open-system air cycle100.

As shown inFIG. 3of power plant1000, the Brayton open-system air cycle100employs a compressor105that pressurizes ambient inlet air101to an intermediate pressure state with fuel601then injected and the air/fuel mixture ignited, the pressurized combustion gas106thereby causing the rotation of turbine120that drives compressor105and generator905that produces electrical energy. Combustion exhaust gas energy source121discharged from combustion turbine120constitutes heat source121athat can be augmented by additional energy created by combusting fuel602using HRU125duct burner605, resulting in heat source121b.HRU125contains a plurality of heat exchangers that sequentially transfer Brayton open-system air cycle100energy source121into the Rankine closed-system cycle200and Brayton closed-system supercritical CO2cycle300. Conduits or pipes direct hot high pressure superheated vapor of the Rankine closed-system cycle200discharged from HRU125to HP turbine245, with Rankine closed-system cycle200intermediate pressure vapor discharged from turbine245reheated by energy exhausted by the combustion turbine120of the Brayton open-system air cycle100and by energy discharged from turbine350of the Brayton closed-system supercritical CO2cycle300. The intermediate pressure reheated fluid of Rankine closed-system cycle200is directed from HRU125by conduits or pipes to intermediate pressure steam turbine265, fluid subsequently discharged to a cooling condenser heat exchanger805with conduits or pipe then directing the Rankine closed-system cycle200liquid to a pump to re-initiate the closed-system Rankine closed-system cycle200. Relative to the Brayton closed-system supercritical CO2cycle300, conduits or pipes direct hot high pressure Brayton closed-system supercritical CO2cycle300from HRU125to high pressure supercritical CO2turbine350. Conduits or pipes direct intermediate pressure Brayton closed-system supercritical CO2cycle300, discharged from supercritical CO2turbine350, to a plurality of heat exchangers and recuperators that transfer energy to both the high pressure Brayton closed-system supercritical CO2cycle300and the high pressure fluid of the Rankine closed-system cycle200. The intermediate pressure supercritical CO2is ultimately cooled by a plurality of heat exchangers810and re-pressurized by a plurality of pumps/compressors305to re-initialize the Brayton closed-system supercritical CO2cycle300. Turbine350of Brayton closed-system supercritical CO2cycle300and turbine245of Rankine closed-system cycle200rotate a plurality of generator(s)910that produces electrical energy.

Referring to ofFIG. 3of power plant1000, the closed-system Rankine closed-system cycle200is herein described in detail. Reduced pressure liquid267enters a plurality of electrically motor driven pumps/compressors205that pressurize low-pressure liquid267to high pressure liquid206directed by conduits or pipes to Rankine closed-system cycle200heat exchanger210where energy is transferred from Brayton closed-system supercritical CO2cycle300intermediate pressure supercritical CO2366into exiting Rankine closed-system cycle200high pressure fluid211. Heated high pressure fluid211is directed by conduits or pipes to Rankine closed-system cycle200heat exchanger215where intermediate pressure supercritical CO2362transfers energy into exiting high pressure liquid216directed by conduits or pipes to Rankine closed-system cycle200heat exchanger220located in HRU125of Brayton open-system air cycle100. Brayton open-system air cycle100heat source121gtransfers energy to Rankine closed-system cycle200high pressure liquid221exiting HRU125heat exchanger220with liquid221then directed by conduits or pipes to Rankine closed-system cycle200heat exchanger/evaporator225where Brayton closed-system supercritical CO2cycle300intermediate pressure supercritical CO2356transfers energy into entering high pressure Rankine closed-system cycle200liquid221that may begin to partially boil. Conduits or pipes transport potentially partially saturated Rankine closed-system cycle200fluid226exiting heat exchanger/evaporator225to HRU125heat exchanger/evaporator230where the boiling process is completed by energy transferred from HRU125heat source121eof Brayton open-system air cycle100. Saturated high pressure fluid231exiting HRU125heat exchanger/evaporator230is transported by HRU125conduits or piping to HRU125heat exchanger235where heat source121dtransfers energy into Rankine closed-system cycle200fluid231that then attains superheated vapor236subsequently transported by conduits or pipes to high pressure turbine245of Rankine closed-system cycle200; de-super heater240can spray fluid into superheated vapor236to prevent excessive fluid temperatures. High pressure superheated vapor241enters turbine245, which rotates a shaft that drives a plurality of generator(s)910. Intermediate pressure vapor246exiting Rankine closed system cycle200turbine245is directed by conduits or pipes to heat exchanger250of Rankine closed-system cycle200where intermediate pressure supercritical CO2361exiting Brayton closed-system supercritical CO2cycle300recuperator heat exchanger330/360superheats intermediate pressure Rankine closed-system cycle200vapor251. Conduits or pipes direct supercritical vapor251from heat exchanger250to HRU125heat exchanger255where Brayton open-system air cycle100heat source121ctransfers energy to further superheat Rankine closed-system cycle200vapor251to a superheated vapor256state. Conduits or pipes transport intermediate pressure super-heated vapor256exiting HRU125heat exchanger255to Rankine closed-system cycle200steam turbine265; de-super heater260can spray fluid into superheated vapor256to prevent excessive fluid temperatures. HRU125heat exchangers235and255are illustrated in a series configuration but could also be arranged in a parallel/series configuration. Intermediate pressure superheated vapor261enters a plurality of Rankine closed-system cycle200intermediate pressure steam turbine(s)265, thereby rotating a shaft that drives a plurality of generator(s)910. Low-pressure fluid266discharged from steam turbine265is directed into condensing heat exchanger805where the cooling fluid804is heated by energy transferred from fluid266exiting steam turbine265, thereby causing the Rankine closed-system cycle200fluid266to revert to liquid267state, then directed by conduits or pipes to a plurality of motor driven pumps/compressors205, thus re-initializing the closed-system Rankine closed-system cycle200.

Referring to power plant1000ofFIG. 3, the energy of heat source121is practically and efficiently distributed to the Rankine closed-system cycle200and Brayton closed-system supercritical CO2cycle300. Further, the energy collectively discharged to the environment's ultimate heats sinks (ambient air and potentially a river, lake or ocean) is minimized, thereby improving the efficiency and output of power plant1000.

Referring toFIGS. 4A, 4B, and 4Cof power plant1005of another embodiment of the invention involves a hybrid-nuclear integration of a Brayton open-system air cycle100, closed-system Rankine closed-system cycle200, Brayton closed-system supercritical CO2cycle300, and Brayton closed-system nuclear cycle400employed to drive the main air compressor of the Brayton open-system air cycle100. The Brayton closed-system nuclear cycle400consists of a working gas (e.g., helium), a nuclear reactor405, a plurality of turbines410and415, a plurality of recuperators440/420and425/435, a plurality of cooling heat exchangers830and835, a plurality of high pressure compressor(s)430driven by a plurality of turbine(s)410of the Brayton closed-system nuclear cycle400, and a plurality of compressor(s)110of the Brayton open-system air cycle100driven by a plurality of turbine(s)415of the Brayton closed-system nuclear cycle400.

Referring to power plant1005ofFIGS. 4A and 4B, the additional embodiment of the invention employing a Brayton closed-system nuclear cycle400is described in detail. Very hot high pressure gas406discharged from nuclear reactor405is directed by a conduit or pipe header to a plurality of parallel conduits or pipes that transport very hot high pressure gases407and408to parallel high pressure turbine410(which drives compressor430cooled by intercooler815) and high pressure turbine415(which drives compressor110of the Brayton open-system air cycle100). Hot intermediate pressure gases417and412(discharged respectively from parallel turbines415and410) are directed by parallel conduits or pipes to parallel recuperator heat exchangers425/435and440/420. Referring to recuperator heat exchanger425/435, intermediate pressure gas417transfers energy to high pressure gas433entering recuperator heat exchanger425/435. Referring to recuperator heat exchanger440/420, intermediate pressure gas412transfers energy to high pressure gas434entering recuperator heat exchanger440/420. Conduits or pipes direct intermediate pressure gases427and422to parallel heat exchanger coolers830and835; the coolers can be associated with refrigeration or absorption cooling systems850used to enhance the efficiency of the overall integrated thermal cycle by reducing the temperature of fluids entering compressors. Conduits or pipes direct cooled intermediate pressure merged gases429and424to intercooled (heat exchanger815) compressor430. High pressure gas432exiting compressor430is directed by conduits or pipes to recuperator heat exchangers425/435and440/420where energy is transferred into high pressure gases433and434from intermediate pressure gases417and412. Conduits or pipes transport high pressure gases437and442from recuperator heat exchangers425/435and440/420and combine the gases into high pressure gas444directed by a conduits or pipes to nuclear reactor405, thereby re-initializing the Brayton closed-system nuclear cycle400cycle. Motor/generators925and920provide the rotational forces needed for initial start-up of turbines410and415as well as providing auxiliary electrical energy.

Referring toFIGS. 4A, 4Ban4C of power plant1005, an embodiment of the disclosure involves enhancing the Brayton open-system air cycle100relative to that of power plant1000ofFIG. 3. As illustrated byFIG. 4C, a dedicated intercooled compressor115and saturator865are employed with gas turbine120to enhance the cooling of turbine120materials, thereby supporting higher gas turbine120firing temperatures, which in turn support increased output as well as efficiency. Refrigeration or absorption cooling system850fluid863associated with the compressor115intercooler860is evaporated into Brayton open-system air cycle100fluid118entering saturator865from compressor115, thereby resulting in reduced temperature fluid119used to cool turbine120components such as stators and blades. Similarly, Brayton open-system air cycle100compressor115working fluid117can be used to cool turbine120parts such as stators and rotors. Additionally, the temperature of Brayton open-system air cycle100working fluid102bentering compressor115ofFIG. 4Cand temperature of working fluid101bentering compressor110ofFIG. 4Bcan be reduced by using cooled fluids created by refrigeration or absorption cooling system850that uses waste energy from various heat exchanger, e.g.,860ofFIG. 4C and 830 and 835ofFIG. 4B. Referring toFIG. 4C, heated fluid861of refrigeration or absorption cooling system850can be used to preheat fuel gas601aused by turbine120ofFIG. 4A, thereby increasing the efficiency of power plant1005.

Referring toFIG. 4Aof hybrid-nuclear power plant1005, the integration of an enhanced Brayton open-system air cycle100, closed-system Rankine closed-system cycle200, and Brayton closed-system supercritical CO2cycle300parallels that described earlier in conjunction withFIG. 3. Broadly, as illustrated byFIG. 4Aof power plant1005, energy transfer between a Rankine closed-system cycle200, Brayton closed-system supercritical CO2cycle300and enhanced Brayton open-system air cycle100is accomplished using a plurality of heat exchanger and recuperators. A plurality of heat exchangers located in EMU125of the enhanced Brayton open-system air cycle100sequentially transfer energy from enhanced Brayton open-system air cycle100to both the Brayton closed-system supercritical CO2cycle300and to Rankine closed-system cycle200. A plurality of heat exchangers and recuperators are used to sequentially transfer energy from intermediate pressure supercritical CO2of the Brayton closed-system supercritical CO2cycle300to both the high pressure supercritical CO2of the Brayton closed-system supercritical CO2cycle300and the high pressure liquid and vapor of the Rankine closed-system cycle200. A plurality of supercritical CO2turbine(s)350of Brayton closed-system supercritical CO2cycle300efficiently optimized the use the HRU125heat source121benergy while the Rankine closed-system cycle200is efficiently optimized by using HRU125heat source121cto support the practical capabilities of steam turbines245and265. HRU125heat exchangers235and255are illustrated byFIG. 4Ain a series configuration but a parallel/series configuration could also be employed.

A further embodiment of the disclosure consists of not intercooling compressor115ofFIG. 4Cand not employing saturator865, thereby simplifying compressor115. This embodiment would, however, result in reduced efficiency and electrical generation relative to the preferred embodiment ofFIGS. 4A, 4B and 4C.

Referring toFIGS. 4A, 4B, and 4Cof the integrated hybrid-nuclear power plant1005, TABLES 1 and 2 provide illustrative energy balance information for the embodiment of the invention involving the integration of a Brayton open-system air cycle100, closed-system Rankine closed-system cycle200, Brayton closed-system supercritical CO2cycle300, and Brayton closed-system nuclear cycle400. Referring to TABLES 1 and 2, the Baseline hybrid-nuclear configuration consists of a conventional Rankine closed-system cycle200employing three reheat steam turbines similar to that illustrated byFIG. 1, but withFIGS. 4A, 4B and 4Cillustrating the configuration of Brayton open-system air cycle100compressors110and115and gas turbine120. Case A is the Hybrid-nuclear configuration ofFIGS. 4A, 4B and 4Cwith no HRU125duct firing605. Case B is the Hybrid-nuclear configuration ofFIGS. 4A, 4B and 4Cwith additional energy provided to HRU125by way of duct firing605using fuel602—heat source121bis roughly 13% hotter than heat source121a.

Referring to power plant1010ofFIG. 5A, a further embodiment of the disclosure involves a nuclear reactor system500employed with a closed-system Brayton closed-system supercritical CO2cycle300and a closed-system Rankine closed-system cycle200. A plurality of conduits or pipes transfer hot nuclear system working fluid506from nuclear reactor505to HRU510where heat sources511athrough511itransfer energy to a plurality of heat exchangers associated with a Brayton closed-system supercritical CO2cycle300and closed-system Rankine closed-system cycle200. A plurality of conduits or pipes transport cooled nuclear system working fluid512from HRU510to pump/circulator525where a plurality of conduits or pipes transport pressurized working fluid516to reactor505, thereby reinitializing the nuclear reactor system500. The energy transfer between the Brayton closed-system supercritical CO2cycle300and closed-system Rankine closed-system cycle200parallels that described for the embodiments of the disclosure illustrated and previously described forFIG. 3for power plant1000and illustrated and previously described forFIGS. 4A, 4B, and 4Cfor power plant1005. Reactor fluids506/511/512/516are not limited to a particular type and could be a gas, liquid, liquid metal, liquid salt or liquid fluid containing fissile material. Additionally, the nuclear reactor system500could include an intermediate heat transfer loop comprised of a second HRU to separate the primary reactor fluid506/512a working fluid employed with HRU510, thereby avoiding or minimizing radioactive contamination and safety issues between the reactor and Brayton closed-system supercritical CO2cycle300and Rankine closed-system cycle200.

Referring power plant1010,FIG. 5B, a further embodiment of the disclosure involves adding additional energy to the high pressure high temperature supercritical CO2of the supercritical CO2Brayton cycle prior to said supercritical CO2entering the high pressure high temperature turbine of said supercritical CO2Brayton cycle. A plurality of conduits or pipes direct a supplemental heating system working fluid751from working fluid storage tank(s)750to a plurality of pump(s)755that direct working fluid756to a plurality of heater(s)760that transfers ignited fuel energy604to heating system working fluid756directed by a plurality of conduits to a plurality heat exchanger(s)770wherein hot supplemental heating system working fluid766transfers energy to supercritical CO2Brayton cycle high temperature high pressure supercritical CO2working346aexiting a plurality of heat exchanger(s)765and subsequently directed by a plurality of conduits or pipes to a plurality of supercritical CO2high pressure high temperature turbine(s)350. The plurality of heater(s)760are comprised of a heat exchanger765and burner772fired by a fuel604, with blower145directing atmospheric air103through heater(s)760. A plurality of conduits or pipes transport reduced temperature working fluid771from heat exchanger770to a plurality of working fluid storage tank(s)750, thereby re-initializing the supplemental heating system. The working fluid of the supplemental heating system can include a variety of fluids, including molten salt, liquid metals, and vapors. Additional energy could be added to the working fluid of the nuclear reactor or working fluid of an intermediate heat transfer loop employing the supplemental heating system similar to that illustrated byFIG. 5B.

Referring to power plant1015ofFIG. 6, a further embodiment of the disclosure involves a solar energy system700employed with a closed-system Brayton closed-system supercritical CO2cycle300and closed-system Rankine closed-system cycle200. A plurality of conduits or pipes transfer hot solar system working fluid706from a plurality of solar energy system700working fluid storage tank705to HRU710where heat sources711athrough711itransfer energy to a plurality of heat exchangers associated with a Brayton closed-system supercritical CO2cycle300and closed-system Rankine closed-system cycle200. A plurality of conduits or pipes transport cooled solar system working fluid712from HRU710to a reduced-temperature solar system working fluid storage tank715from which a plurality of conduits or pipes transfer said solar system working fluid716to pump/circulator720where a plurality of conduits or pipes transport pressurized solar system working fluid721to solar receiver725, from which a plurality conduits or pipes transfer high temperature solar system fluid726to solar system working fluid storage tank705, thereby reinitializing the solar energy system700. The energy transfer between the Brayton closed-system supercritical CO2cycle300and closed-system Rankine closed-system cycle200parallels that described for the embodiments of the disclosure illustrated and previously described forFIG. 3for power plant1000and illustrated and previously described forFIGS. 4A, 4B, and 4Cfor power plant1005. Solar system working fluids706/712/716/721/726are not limited to a particular type and could be a gas, liquid, liquid metal, or liquid salt.

Referring to power plant1015ofFIG. 6, a further embodiment of the disclosure involves adding additional energy to the high temperature solar energy system700working fluid706acirculated between a plurality of storage tank(s)705and plurality of heater(s)740, with heated solar energy system700working fluid706creturned to storage tank(s)705. Supplemental heating system heater740is comprised of heat exchanger745and burner752fired by a fuel603with blower145directing atmospheric air102through heater740. A plurality of conduits or pipes direct hot solar energy system working fluid706afrom a plurality of high temperature working fluid storage tank(s)705to a plurality of pump735that direct working fluid706bto a plurality of heater(s)740where ignited fuel energy603transfer energy to working fluid706cdirected by a plurality of conduits or pipes to working fluid storage tank705, thereby re-initialized the supplemental heating system.

Referring to power plants1000,1005,1110and1115ofFIGS. 3, 4, 5, and 6, a further embodiment of the disclosures is comprised of employing clutches with a plurality of generator(s)910and plurality of supercritical CO2turbine(s)350and plurality of intermediate pressure Rankine closed-system cycle200turbine(s)245, allowing generator(s)910to disengage from the plurality of turbines245and350and thereby allow the plurality of generator(s)910to operate as a synchronous condenser during periods when power plants1000,1005,1010and1115are offline. Such a feature helps stabilize power grids subjected to intermittent renewable energy while providing an additional revenue source for power plants1000,1005,1010, and1015.

The disclosure's embodiments share a common feature whereby Brayton closed-system supercritical CO2cycle300energy transfer is accomplished by employing a plurality of heat exchangers and recuperator heat exchangers as opposed to employing a few recuperator heat exchangers, as illustrated byFIG. 2. TABLE 3 illustrates the difference.

Referring to power plants1000,1005,1010and1015, embodiments of the disclosure use of a Rankine closed-system cycle200with the other thermal cycles, thereby readily supporting a wide range of applications including: industrial processes; chemical production; cogeneration; municipal heating/cooling; desalination. All manner of steam pressures and temperatures are available using steam turbine extraction and/or steam de-superheators and pressure reducing valves. Sole use of a supercritical CO2cycle has limited flexibility in support of such applications.

The use of a plurality of thermal cycles with the Brayton open-system air cycle100allows for simpler control of the closed-system Rankine closed-system cycle200because fewer and simpler Rankine closed-system cycle200turbines can be used.

Referring to power plants1000,1005,1010and1015, the embodiments of the disclosure can use a plurality of air cooled condenser heat exchanger(s)805to transfer Rankine closed-system cycle200energy to the atmosphere ultimate heat sink from low-pressure Rankine closed-system cycle200working fluid discharged from the Rankine closed-system cycle200intermediate pressure turbine, thereby condensing the Rankine closed-system cycle200working fluid to a liquid state. The embodiments of the disclosure can also use a plurality of water cooled condenser heat exchangers805to transfer Rankine closed-system cycle200energy to the atmosphere ultimate heat sink by way of using a plurality of forced mechanical draft or natural daft cooling towers in which cooling system working fluid water is circulated between the condenser heat exchanger(s)805and mechanical or natural draft cooling tower(s). The embodiments of the disclosure can also use a plurality of water cooled condenser heat exchanger(s)805to transfer Rankine closed-system cycle200energy to an ultimate heat sink in the form of a river, lake or ocean by directing, using a plurality of pumps, river, lake or ocean cooling water to the plurality of condenser heat exchanger(s)805and then returning the heated water to the river, lake, or ocean.

Referring to power plants1000,1005,1010and1015, Brayton cycle heat exchanger coolers810,830and835transfer Brayton open-system air cycle100and Brayton closed-system supercritical CO2cycle300energy to the coolest ultimate heat sinks by moving cooling system working fluid through the plurality of heat exchanger coolers810,830and835. Refrigeration or absorption cooling system850could also be used to further reduce the temperature of the cooling system working fluid, thereby reducing the energy required to pressurize and/or compress cycles100,300and400working fluids. Refrigeration or absorption cooling system850could be an absorption system using waste heat from the thermal cycles100,300or400and/or a mechanical compression refrigeration system.

The use of the Brayton closed-system supercritical CO2cycle300allows for more practical use of very hot energy discharged by the gas turbine of the Brayton open-system air cycle100because modest temperature high pressure supercritical CO2can be used to cool supercritical CO2turbine rotors, stators and materials initially exposed to high temperature high pressure supercritical CO2entering the supercritical CO2turbine(s). The cooled supercritical CO2turbines also support supplemental heating of the Brayton closed-system supercritical CO2cycle and open-system Brayton, as described previously and summarized in the following paragraph.

Referring to power plants1000(FIG. 3),1005(FIG. 4A),1110(FIG. 5B) and1115(FIG. 6), embodiments of the disclosure can use supplementally-fired heaters to augment heat source energy. Such augmented heat source energy increases the ability of said power plants to provide additional peaking energy to the electrical grid. Said additional energy can be derived from a variety of fossil fuels such as natural gas, gasified coal, and/or liquid fossil fuel. Said additional energy can also be derived from hydrogen derived from the electrolysis of water and wherein said hydrogen can be stored to support grid peaking applications and wherein said electrolysis input energy can be provided from intermittent renewable energy sources such as solar panels or wind turbines. No CO2emissions occur when renewable energy sources provide the energy for electrolysis derived hydrogen used in support of power plant1000,1005,1010, and1015temporary power increases.

The embodiments of this disclosure include methods to use temperature differences between heat sources and heat sinks through the integration of a plurality of thermodynamic cycles, thereby improving plant efficiencies, attendant power outputs, and power plant economics. Although a combination of features is shown in the illustrated examples, not all of them need be combined to realize the benefits of the various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all the features shown in any one of the figures or all of the portions schematically shown in the figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.

The preceding descriptions are exemplary rather limiting in nature. Variations and modifications that do not necessarily depart from the essence of this disclosure to the disclosed examples may become apparent to those skilled in the art.