EP2776712A1 - Methods and apparatus for thermal energy storage control optimization - Google Patents
Methods and apparatus for thermal energy storage control optimizationInfo
- Publication number
- EP2776712A1 EP2776712A1 EP12847282.6A EP12847282A EP2776712A1 EP 2776712 A1 EP2776712 A1 EP 2776712A1 EP 12847282 A EP12847282 A EP 12847282A EP 2776712 A1 EP2776712 A1 EP 2776712A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- heat transfer
- transfer fluid
- phase change
- bucket
- change material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
- F28D20/02—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using latent heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S10/00—Solar heat collectors using working fluids
- F24S10/30—Solar heat collectors using working fluids with means for exchanging heat between two or more working fluids
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03G—SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR
- F03G6/00—Devices for producing mechanical power from solar energy
- F03G6/003—Devices for producing mechanical power from solar energy having a Rankine cycle
- F03G6/005—Binary cycle plants where the fluid from the solar collector heats the working fluid via a heat exchanger
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S60/00—Arrangements for storing heat collected by solar heat collectors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
- F24S60/00—Arrangements for storing heat collected by solar heat collectors
- F24S60/10—Arrangements for storing heat collected by solar heat collectors using latent heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
- F28D2020/0065—Details, e.g. particular heat storage tanks, auxiliary members within tanks
- F28D2020/0082—Multiple tanks arrangements, e.g. adjacent tanks, tank in tank
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
- Y02E10/44—Heat exchange systems
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/40—Solar thermal energy, e.g. solar towers
- Y02E10/46—Conversion of thermal power into mechanical power, e.g. Rankine, Stirling or solar thermal engines
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/14—Thermal energy storage
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E70/00—Other energy conversion or management systems reducing GHG emissions
- Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin
Definitions
- the embodiments disclosed herein are directed toward control optimization methods and apparatus for thermal energy storage.
- the disclosed embodiments are more particularly directed toward control optimization for thermal energy storage in a cascaded phase change material thermal energy storage system associated with a concentrated solar power generation system.
- the basic phase change material thermal energy storage concept features the use of a material with a melting temperature in between the hot and cold side temperatures of a solar field as a thermal energy storage medium.
- heat transfer fluid from the solar field is cooled by melting the phase change material.
- phase change material based system relatively cool heat transfer fluid is heated by running it in reverse through the thermal energy storage system thus solidifying the phase change material.
- the benefit of a phase change material based system is the high energy density realized by exploiting the latent heat of a suitable material in addition to utilizing the sensible heat.
- the energy storage density of a suitable energy storage material can typically be doubled by adding latent heat storage over a 100 °C temperature range.
- Phase change material based thermal energy storage systems must include multiple types of salts with different melt temperatures to effectively store and discharge energy over a temperature range of 100 °C or more.
- the total amount of energy that can be stored for a given storage mass over the 100 °C temperature differential can be greatly increased.
- the forgoing arrangement of linearly arrayed phase change material groups, (with each group or container of a given phase change material being known as a "bucket") is called a cascade and can be thought of like a cascading waterfall, with the highest melt temperature at the top followed by progressively lower melt temperatures to the bucket at the bottom.
- phase change material thermal energy storage system having a sufficient number of buckets provides for energy storage at the highest temperature possible.
- a theoretical best case phase change material system would have an exceptionally large number of phase change material buckets with different melt temperatures spread equally through the range of expected heat transfer fluid temperatures.
- Implementing an exceptionally large number of distinct phase change material buckets is not practical however, in part because there are a limited number of suitable phase change material choices. It is generally more feasible to utilize 3-5 phase change materials with melt temperatures spread as evenly as possible throughout the designed storage temperature range.
- thermal energy storage systems can be described as belonging to one of two categories: active and passive.
- An active system is classified as a system that actively engages its storage material with the system's heat transfer fluid, typically through mechanical interactions.
- a two-tank molten salt system is classified as an active system because the molten salt is actively pumped.
- Passive systems do not have mechanical interaction.
- a common example of a passive system is concrete storage where the storage material encases heat transfer fluid pipes and passively accepts and gives thermal energy to the working fluid.
- a phase change material thermal energy storage system as described above is a type of passive storage system.
- phase change material storage system Certain physical limitations cause difficulty controlling a passive phase change material storage system for optimal transient performance.
- the salts used as phase change materials have very low heat transfer rates compared to the heat transfer fluid.
- the lower heat transfer rate of a phase change material occurs in part because the material is stationary and also because suitable phase change materials conduct heat poorly. Low heat transfer rates cause power output from the storage system to be lower even if the total energy storage is
- phase change materials accept and release heat isothermally over the melting region whereas heat transfer fluid accepts and releases heat over a range of
- the highest temperature bucket will have a substantially lower temperature than the maximum heat transfer fluid temperature.
- day-to-day repeatability presents a significant difficulty in the operation of a passive thermal energy storage system.
- Problems arise from driving temperature differences during charge and discharge in combination with variable solar field outlet temperature and variation in heat transfer fluid flow rates.
- a third bucket may have a driving temperature difference of nearly 30°C during charge compared to only a 10°C temperature difference during discharge. These temperature differences are constrained by the availability of materials with desired melt temperatures.
- a bucket sees a varying mass heat transfer fluid flow rate that may fluctuate between 0 kg/s and a maximum rate during charge operation compared to a constant mass flow rate at or near the maximum during discharge.
- the heat transfer characteristics for a given phase change material salt are different for charge and discharge.
- One embodiment is a solar power generation system including a heat transfer fluid circuit, a solar energy concentrator and a thermal energy storage system.
- the thermal energy storage system comprises a cascaded series of multiple buckets of phase change material all in thermal communication with the heat transfer fluid circuit.
- an outlet from one of the buckets of the thermal energy storage system is in direct communication through a secondary branch of the heat transfer fluid circuit with an inlet into a power block steam train component.
- the secondary branch provides for the routing of some or all of the heat transfer fluid flowing from the solar field to the power block through a storage bucket during active energy production.
- the bucket in direct thermal communication with the power block may be a high temperature bucket containing a phase change material that has a melting temperature greater than the phase change materials contained in other buckets of the cascaded series.
- a related embodiment is a cascaded thermal energy storage system having multiple buckets of phase change material connected in series by a heat transfer fluid circuit.
- This embodiment further includes a secondary branch of the heat transfer fluid circuit connecting an outlet of one or more buckets directly to a power block inlet. The foregoing connection is made through the secondary branch while producing energy within the power block.
- Another related embodiment is a method of utilizing solar energy comprising the following steps; providing a heat transfer fluid circuit, a solar energy concentrator, a cascaded thermal energy storage system and a power block all connected by a primary heat transfer fluid circuit. The method further includes flowing heat transfer fluid from the solar energy
- the bucket may be a high temperature bucket containing a phase change material that has a melting temperature greater than the phase change materials contained in other buckets of the cascaded series.
- Another embodiment is a solar power generation system generally as described above but further comprising an inlet to one or more selected buckets of the thermal energy storage system in direct communication through a secondary branch of the heat transfer fluid circuit with an outlet from a power block component.
- an outlet from the one or more selected buckets is in direct communication through the heat transfer fluid circuit with the solar energy concentrator or the power block.
- This configuration provides for heat transfer fluid flow to be preheated after at least one bucket of the thermal energy storage system has been substantially discharged but before the thermal energy system is recharged.
- the buckets of the thermal energy storage system in communication with the power block outlet may be colder temperature buckets containing a phase change material that has a lower melting temperature than the phase change materials contained in at least one other bucket of the cascaded series.
- a related embodiment includes a cascaded thermal energy storage system as generally described above but further comprising at least one secondary branch of the heat transfer fluid circuit connecting an outlet from the power block to the inlet to one or more buckets of the cascaded thermal energy storage system.
- a related embodiment includes a method of preheating a solar energy system comprising the step of flowing heat transfer fluid from a power block outlet through one or more partially discharged buckets of the thermal energy storage system prior to charging the thermal energy storage system.
- the method thus provides for preheating heat transfer fluid which may then be flowed to the solar energy concentrator and the power block before active power generation commences.
- An alternative embodiment includes a solar power generation system as generally described above but further comprising multiple secondary heat transfer fluid circuit branches directly connecting at least two buckets of the thermal energy storage system to at least two corresponding steam train components.
- the secondary heat transfer fluid branches provide for direct heat transfer fluid injection between individual phase change material buckets and corresponding steam train components during the discharge phase of power generation.
- the melting temperature of the phase change material in each bucket may correspond to the designed operating temperature of the corresponding steam train component.
- a related embodiment includes a cascaded thermal energy storage system as generally described above but further comprising multiple secondary branches of the heat transfer fluid circuit connecting outlets from at least two buckets to inlets to at least two steam train components during discharge of the thermal energy storage system.
- the melting temperature of the phase change material in each bucket may correspond to the designed operating temperature of the corresponding steam train component.
- a related embodiment includes a method of utilizing solar energy comprising the step of flowing heat transfer fluid from at least two selected buckets of phase change material to the inlet of at least two corresponding steam train components while discharging the thermal energy storage system. This method provides for direct heat transfer fluid injection between individual phase change material buckets and corresponding steam train components during the discharge phase of power generation.
- Another embodiment includes a solar power generation system generally as described above but further comprising secondary branches of the heat transfer fluid circuit connecting one or more buckets of the thermal energy storage system with an outlet from the power block and further connecting the one or more buckets with the solar energy concentrator.
- This embodiment provides for heat transfer fluid flowing in the heat transfer fluid circuit to be heated by partial discharge of the thermal energy storage system during periods of insufficient insolation to charge the thermal energy storage system.
- the one or more buckets of the thermal energy storage system in communication with the power block outlet may be colder temperature buckets containing a phase change material that has a lower melting temperature than the phase change materials contained in other buckets of the cascaded series.
- a related embodiment includes a cascaded thermal energy storage system generally as described above but further comprising one or multiple secondary branches of the heat transfer fluid circuit connecting the power block to an inlet to one or more buckets during periods of insufficient insolation to charge the thermal energy storage system.
- a related embodiment is a method of utilizing solar energy comprising the step of partially discharging the thermal energy storage system during periods of insolation too low to charge the thermal energy storage system by flowing heat transfer fluid from the power block outlet through one or more buckets of the thermal energy storage system.
- Another embodiment includes a solar power generation system as generally described herein comprising any combination of secondary branches of the heat transfer fluid circuit extending between selected phase change material buckets and selected steam train components and/or any combination of secondary branches of the heat transfer fluid circuit extending between selected phase change material buckets and the solar field.
- a related embodiment is a cascaded thermal energy storage system generally as described above further comprising any combination of secondary branches of the heat transfer fluid circuit extending between selected phase change material buckets and selected steam train components and/or any combination of secondary branches of the heat transfer fluid circuit extending between selected phase change material buckets and the solar field.
- Fig. 1 is schematic diagram representation of a prior art concentrated solar power generation system operating in charge mode.
- Fig. 2 is schematic diagram representation of a prior art concentrated solar power generation system operating in discharge mode.
- FIG. 3 is schematic diagram representation of an improved concentrated solar power generation system operating to produce energy.
- Fig. 4 is schematic diagram representation of an improved concentrated solar power generation system during warm-up operations prior to charging and after discharge.
- FIG. 5 is schematic diagram representation of an improved concentrated solar power generation system operating in discharge mode.
- Fig. 6 is schematic diagram representation of an improved concentrated solar power generation system operating in a partial discharge mode.
- Fig. 7 is schematic diagram representation of a concentrated solar power generation system featuring a combination of improvements.
- FIG. 1 A conventional concentrated solar energy power generation system 100 is schematically illustrated in Figs. 1 and 2.
- Various embodiments of solar powered generation systems having enhanced thermal energy storage control methods and apparatus are disclosed herein and illustrated in Figs. 3-7.
- the enhanced thermal energy storage embodiments disclosed herein are improvements upon the basic design of Figs. 1 and 2
- the solar power generation system 100 of Figs. 1 and 2 may be considered to have multiple functional blocks including; one or more solar energy concentrators 102, one or more thermal energy storage systems 104 and one or more power blocks 106.
- a commercially implemented solar power generation system 100 will generally have many solar energy concentrators 102 in a solar field for each thermal energy storage system 104 or power block 106.
- the solar energy concentrator elements 102 may be of any known type, including but not limited to, parabolic trough reflectors, heliostat based solar energy towers or similar apparatus. In all cases the solar concentrator element 102 concentrates reflected sunlight upon the surface of a tube or other receiver structure within which heat transfer fluid is circulated. The heat transfer fluid is thus heated by the concentrated sunlight to a temperature sufficient to drive a steam turbine generator as described below.
- the solar energy concentrator 102, thermal energy storage system 104 and power block 106 are each maintained in thermal communication through a heat transfer fluid circuit 108.
- the heat transfer fluid circuit 108 as shown on Figs. 1 and 2 is referred to herein as the primary heat transfer fluid circuit.
- the heat transfer fluid circuit 108 has heat transfer fluid flowing within pipes, valves, pumps, heat exchange elements and other structures of the circuit 108.
- the heat transfer fluid flowing in the circuit 108 is typically heat transfer oil or other liquid having appropriate chemical, thermal and physical qualities.
- the power block 106 includes various steam train components 110 which provide for heat exchange between heat transfer fluid flowing in the heat transfer fluid circuit 108 and water flowing in a steam circuit 112.
- the power block 106 includes at least the following steam train components; a pre -heater 114, an evaporator 116 and a super-heater 118, arranged in order from lesser to greater operational temperature.
- heat is exchanged between the heat transfer fluid circuit 108 and the steam circuit 112 resulting in the production of super heated steam which may be used to drive a steam turbine 120 for power generation. It is important to note that a commercially implemented power block is substantially more complex than schematically illustrated in Fig. 1.
- the thermal energy storage system 104 includes a series of multiple buckets, each containing a phase change material having a selected melting temperature.
- phase change material buckets 122, 124, and 126 respectively are illustrated in a cascaded series. It is important to note however, that a commercially implemented thermal energy storage system may have more than or less than 3 buckets.
- a commercially implemented system may have multiple containers of any shape or size holding a specific type of phase change material. In this case, each collection of interlinked containers holding the same phase material constitutes one functional bucket.
- the buckets 122, 124, 126 are arranged in a cascade. As defined herein, a
- phase change material bucket 122 nearest the outlet from the solar field is designated as a "hot” phase change material bucket.
- This bucket contains a phase change material having a melting point temperature higher than the phase change materials contained in other buckets in the series.
- a heat transfer fluid circuit outlet from the hot phase change material bucket 122 leads to an inlet to a medium phase change material bucket 124.
- An outlet from the medium temperature phase change material bucket 124 leads to a cold bucket 126 and so on until a complete cascade from the highest temperature bucket to lowest temperature bucket is complete.
- relatively simple or more complex heat exchange apparatus provides for heat exchange between the heat transfer fluid flowing in the heat transfer fluid circuit 108 and the phase change material contained within each bucket.
- the solar power generation system 100 may be operated in two modes with respect to the thermal energy storage system 104; charge mode and discharge mode. Operation in the charge mode is schematically represented in Fig. 1.
- charge mode incident solar radiation falling upon a solar energy concentrator 102 is concentrated by reflection upon a portion of the heat transfer fluid circuit 108 flowing through or near the concentrator.
- relatively cooler heat transfer fluid enters a solar field inlet 128 in the heat transfer fluid circuit 108 and flows to a solar field outlet 130 on the opposite side of a solar energy concentrator 102 while being heated by concentrated sunlight.
- the heated heat transfer fluid is routed to the power block 106 and/or the thermal energy storage system 104.
- the heat transfer fluid flows through various steam train components to create super-heated steam for power generation as described above.
- the cooled heat transfer fluid is then returned in the heat transfer fluid circuit 108 to the solar field for additional heating.
- a portion of the heat transfer fluid in the heat transfer fluid circuit 108 may be routed through the thermal energy storage system 104.
- heat transfer fluid flows first into the phase change material hot bucket 122, then into the medium temperature bucket 124 and finally into the coldest temperature bucket 126.
- heat exchange with the phase change material causes heat energy to be transferred to the phase change material.
- heat is transferred to the phase change material until the phase change material becomes fully molten.
- the somewhat cooled heat transfer fluid exiting bucket 122 still is sufficiently hot to melt the material in bucket 124 and so on.
- the thermal energy storage system may be described as "charged” or fully charged.
- a solar energy power generation system 100 may be operated in charge mode at the discretion of the system operator provided sufficient insolation is available to heat the heat transfer fluid flowing through the solar energy concentrators 102 to a sufficiently high temperature to melt the phase change material in each bucket.
- the thermal energy storage system 104 provides the system 100 with the ability to generate power for a period of time after the sun has set or when the sun is obscured by cloud cover.
- the system is defined herein as being operated in a "discharge" mode. Operation of the basic system in the discharge mode is schematically illustrated in Fig. 2. As shown in Fig. 2, heat transfer fluid flowing in the heat transfer fluid circuit 108 flows through the steam train components 110 in the same direction to accomplish the same steam and power production steps described above. In discharge mode however, the high temperature heat transfer fluid is obtained by flowing cooled heat transfer fluid in reverse order through the cascaded buckets of phase change material.
- cooled heat transfer fluid is flowed through the cold phase change material bucket 126, the medium temperature phase change bucket 124 and the hot phase change material bucket 122 in that order. As the phase change material in each bucket solidifies, heat is transferred to the heat transfer fluid.
- the thermal energy storage system may be described as fully “discharged” and typically it is inefficient or impossible to further extract sensible heat from the system for additional power generation.
- Fig. 3 schematically illustrates an improved method and apparatus for optimizing the control of a thermal energy storage system 104 to improve transient performance.
- the enhanced method illustrated in Fig. 3 includes routing some or all of the heat transfer fluid flow from the solar field through a phase change material bucket before the heat transfer fluid is routed to the power block 106. This re-routing occurs during active energy production.
- some or all of the heat transfer fluid taken from the solar field outlet 130 over a selected period of time may be routed through the hot phase change material bucket 122 before sending it to the power block.
- the hot bucket 122 can charge fully even when the charge driving temperature difference is much lower than the discharge driving temperature difference.
- FIG. 4 An alternative control improvement method and apparatus is schematically illustrated in Fig. 4.
- This embodiment includes preheating the system 100 in the morning or when the system is otherwise cold by more fully discharging one or more relatively colder temperature buckets, for example bucket 126. Because the melt temperatures of the one or more cold buckets are too low to heat the heat transfer fluid sufficiently to run the power block after the hot bucket 122 has fully discharged, the thermal energy storage system 104 and power block 106 must typically be shut down when there is still some latent energy available in the colder buckets. This energy can be used to improve overall plant performance by discharging it to preheat the solar field and power block 106 before the commencement of power generation operations.
- the startup period for a concentrated solar power plant is traditionally long, on the order of an hour. This period is required to warm up the turbines and the heat transfer fluid in the heat transfer fluid circuit pipes.
- This period is required to warm up the turbines and the heat transfer fluid in the heat transfer fluid circuit pipes.
- Using the cold buckets to do some portion or all of the required preheating will allow the system 100 to begin power production earlier in the day, thus increasing total power output.
- this method and apparatus causes the cold buckets to become fully discharged so the thermal energy storage system 104 can more efficiently be charged during the day.
- Implementation of the method of pre-heating the colder buckets requires the addition of one or more secondary branches to the heat transfer fluid circuit, for example pipe 134 leading from the power block to bucket 126 and then on to the inlet 128 of the solar field or back to the power block.
- pipe 134 leading from the power block to bucket 126 and then on to the inlet 128 of the solar field or back to the power block.
- FIG. 5 An alternative control improvement method and apparatus is schematically illustrated in Fig. 5.
- This embodiment includes direct heat transfer fluid injection between individual phase change material buckets and corresponding steam train components during the discharge phase of power generation.
- the heat transfer fluid temperature at the outlet of the phase change material cascade during discharge is required to be slightly less than the designed maximum power block inlet temperature; otherwise the heat transfer fluid at the maximum power block inlet temperature could not effectively charge the hot bucket 122. Therefore, the steam train 110 can not receive the designed maximum heat input during discharge operation.
- the various buckets in the thermal energy storage system may be linked through heat transfer circuit inlet and outlet pipes with any of the steam train components, it is desirable to match the discharge temperature of a selected bucket with the optimum operating temperature of the corresponding steam train component.
- the melting temperature of the phase change material in a given bucket may be approximately equal to the designed operating temperature of the corresponding steam train component.
- this embodiment may be implemented with one or more secondary branches to the heat transfer fluid circuit, for example, pipes 136 and 138 leading from intermediate buckets to corresponding steam train components.
- secondary heat transfer fluid pipes 140 and 142 may be required leading from the steam train back to the next warmest bucket
- FIG. 6 An alternative control improvement method and apparatus is schematically illustrated in Fig. 6.
- This embodiment features partial discharge of the thermal energy storage system 104 during periods of low insolation.
- heat transfer fluid flow from the solar field to the power block 106 is supplemented with heat transfer fluid flow from the thermal energy storage system 104 to maintain the optimum power block inlet flow rate.
- the colder buckets in a thermal energy storage system 104 typically have excess stored energy when compared to the hot bucket 122, it is possible to discharge the colder buckets 124, 126 first while maintaining full charge in the hot bucket.
- this embodiment features the routing of heat transfer fluid flow from the outlet of the steam train through one or two cold buckets to preheat it before sending it to the solar field for final solar heating to an operational temperature.
- the implementation of this improvement requires one or more secondary branches to the heat transfer fluid circuit, for example pipes 144 and 146 as shown on Fig. 6.
- Pipe 144 leads from the outlet of bucket 124 to the solar field inlet 128 and pipe 146 leads from the outlet of bucket 126 to the solar field inlet 128.
- FIG. 7 schematically illustrates a system 100 featuring each of the control
- the Fig. 7 embodiment includes, but is not limited to a solar power generation system or thermal energy storage system, that comprises both the primary heat transfer fluid circuit of Figs. 1 and 2, in particular heat transfer fluid circuit element 108 and various secondary heat transfer fluid circuit branches.
- the secondary heat transfer fluid circuit branches can be implemented in any combination and include but are not limited to pipes 132, 134, 136, 138, 140, 142, 144 and 146.
- the implementation of each improvement disclosed herein in any combination provides a concentrated solar power generation system operator with a great deal of flexibility over the charge and discharge management of a cascaded phase change material thermal energy storage system.
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Abstract
Description
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Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US201161558275P | 2011-11-10 | 2011-11-10 | |
PCT/US2012/060375 WO2013070396A1 (en) | 2011-11-10 | 2012-10-16 | Methods and apparatus for thermal energy storage control optimization |
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EP2776712A1 true EP2776712A1 (en) | 2014-09-17 |
EP2776712A4 EP2776712A4 (en) | 2015-07-15 |
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EP12847282.6A Withdrawn EP2776712A4 (en) | 2011-11-10 | 2012-10-16 | Methods and apparatus for thermal energy storage control optimization |
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US (1) | US20140299122A1 (en) |
EP (1) | EP2776712A4 (en) |
CL (1) | CL2014001129A1 (en) |
ES (1) | ES2540427R1 (en) |
WO (1) | WO2013070396A1 (en) |
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US20140238634A1 (en) * | 2013-02-26 | 2014-08-28 | Battelle Memorial Institute | Reversible metal hydride thermal energy storage systems, devices, and process for high temperature applications |
US10030636B2 (en) * | 2013-05-27 | 2018-07-24 | Stamicarbon B.V. Acting Under The Name Of Mt Innovation Center | Solar thermal energy storage system |
CN204187874U (en) * | 2014-05-22 | 2015-03-04 | 深圳市爱能森设备技术有限公司 | A kind of energy storage type solar steam boiler adopting heat-conducting oil |
ES2565690B1 (en) * | 2014-09-05 | 2017-01-20 | Abengoa Solar New Technologies,S.A. | Method and thermal storage system for solar steam generation plant and solar steam generation plant |
ES2763902T3 (en) * | 2015-03-20 | 2020-06-01 | Siemens Gamesa Renewable Energy As | Procedure to operate a thermal energy storage plant |
CN105698146A (en) * | 2016-03-24 | 2016-06-22 | 王顺滔 | Solar steam boiler |
EP3810352A4 (en) | 2018-06-20 | 2022-09-07 | David Alan McBay | Method, system and apparatus for extracting heat energy from geothermal briny fluid |
EP3990837B1 (en) * | 2019-06-26 | 2024-06-05 | University of Houston System | Systems and methods for full spectrum solar thermal energy harvesting and storage by molecular and phase change material hybrids |
US20210278147A1 (en) * | 2020-03-05 | 2021-09-09 | Uchicago Argonne, Llc | Additively Manufactured Modular Heat Exchanger Accommodating High Pressure, High Temperature and Corrosive Fluids |
CN113587064B (en) * | 2021-07-12 | 2022-05-06 | 西安交通大学 | Mirror field starting and stopping system of photo-thermal power station and control method |
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US4841946A (en) * | 1984-02-17 | 1989-06-27 | Marks Alvin M | Solar collector, transmitter and heater |
US6313391B1 (en) * | 1999-04-02 | 2001-11-06 | Russell M. Abbott | Solar power system using thermal storage and cascaded thermal electric converters |
WO2009108896A1 (en) * | 2008-02-27 | 2009-09-03 | Brilliant Film, Llc | Concentrators for solar power generating systems |
WO2010045130A2 (en) * | 2008-10-13 | 2010-04-22 | Saint-Gobain Ceramics & Plastics, Inc. | System and process for using solar radiation to produce electricity |
US20100101621A1 (en) * | 2008-10-28 | 2010-04-29 | Jun Xu | Solar powered generating apparatus and methods |
BRPI1016140A2 (en) * | 2009-04-09 | 2016-04-19 | Carding Spec Canada | apparatus for transfer and collection of solar energy. |
EP2480837A1 (en) * | 2009-09-23 | 2012-08-01 | Eagle Eye Research, INC. | Solar concentrator system with fixed primary reflector and articulating secondary mirror |
EP2496903A2 (en) * | 2009-10-14 | 2012-09-12 | Infinia Corporation | Systems, apparatus and methods for thermal energy storage, coupling and transfer |
WO2011067773A1 (en) * | 2009-12-06 | 2011-06-09 | Heliofocus Ltd. | Thermal generation systems |
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- 2012-10-16 US US14/357,295 patent/US20140299122A1/en not_active Abandoned
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CL2014001129A1 (en) | 2014-12-19 |
WO2013070396A1 (en) | 2013-05-16 |
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