WO2010146194A1 - Solar thermal power station with exergetic management of heat - Google Patents

Solar thermal power station with exergetic management of heat Download PDF

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Publication number
WO2010146194A1
WO2010146194A1 PCT/ES2010/000229 ES2010000229W WO2010146194A1 WO 2010146194 A1 WO2010146194 A1 WO 2010146194A1 ES 2010000229 W ES2010000229 W ES 2010000229W WO 2010146194 A1 WO2010146194 A1 WO 2010146194A1
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WO
WIPO (PCT)
Prior art keywords
fluid
exchanger
storage
heat
thermal
Prior art date
Application number
PCT/ES2010/000229
Other languages
Spanish (es)
French (fr)
Inventor
José María MARTÍNEZ-VAL PEÑALOSA
Manuel VALDÉS DEL FRESNO
Alberto ABÁNADES VELASCO
Ruben Amengual Matas
Mireia PIERA CARRETÉ
María José MONTES PITA
Antonio Rovira De Antonio
Javier MUÑOZ ANTÓN
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Universidad Politécnica de Madrid
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Publication of WO2010146194A1 publication Critical patent/WO2010146194A1/en

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Classifications

    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/006—Methods of steam generation characterised by form of heating method using solar heat
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K3/00—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K3/00—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein
    • F01K3/12—Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein having two or more accumulators
    • 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
    • F03G6/06—Devices for producing mechanical power from solar energy with solar energy concentrating means
    • F03G6/064—Devices for producing mechanical power from solar energy with solar energy concentrating means having a gas turbine cycle, i.e. compressor and gas turbine combination
    • 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
    • F03G6/06—Devices for producing mechanical power from solar energy with solar energy concentrating means
    • F03G6/065—Devices for producing mechanical power from solar energy with solar energy concentrating means having a Rankine cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S90/00—Solar heat systems not otherwise provided for
    • 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
    • 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

Definitions

  • the invention falls within the field of thermal power plants whose thermal source is solar radiation, concentrated by some of the possible modes of optical concentration, and particularly by means of fields of parabolic trough collectors with absorber tube in the focal axis , or through mirrors of concentration of the radiation on a central receiver located in a tower.
  • thermal power plants whose thermal source is solar radiation, concentrated by some of the possible modes of optical concentration, and particularly by means of fields of parabolic trough collectors with absorber tube in the focal axis , or through mirrors of concentration of the radiation on a central receiver located in a tower.
  • thermodynamic cycle which can be used by a Rankine type cycle, with a vapor that condenses in the cold focus of the cycle, or a Brayton type cycle, with a gas that does not condense, as a working fluid.
  • the invention relates to the way of structuring the various components of the plant, so that it takes full advantage of the solar energy collection capacity of its solar collector battery, depending on the type of cycle and its nominal performance. Regarding the latter, it is especially taken into account that the turbine of the cycle will have its best performance when the working fluid enters it with the nominal temperature, pressure and flow.
  • the invention takes into account the variation of the power of solar irradiation, both daily and seasonal, and the relevance, therefore, of having a thermal storage, which in turn can be of various types, but which It must be adjusted properly so that, for as long as possible, the plant operates in nominal conditions.
  • thermodynamic cycle there is a wide variety of systems to structure solar power plants.
  • An essential alternative is if the same fluid is used in the thermodynamic cycle and in the solar collector battery, this being understood as the set of elements where the absorption of solar radiation occurs.
  • the same fluid, or different fluids can be used for the collector battery and for the cycle, depending on the type of cycle especially.
  • heat fluid the one that extracts the heat from the solar collector battery, and by working fluid to the one that evolves in the thermodynamic cycle.
  • the heating fluid is a thermal oil, such as the Therminol VP; while the working fluid of the thermodynamic cycle is water, which follows a Rankine cycle, where three levels of thermal performance are typically found; water preheating; the boiling of it; and overheating.
  • the heating fluid is usually a molten salt; typically using water as a working fluid.
  • gas non-condensable
  • the gas can also be used as a heating fluid.
  • the gas has to be compressed to the nominal high pressure, and circulated through the solar collector battery so that it is heated, being sent to the gas turbine for expansion, with the consequent conversion into mechanical energy.
  • thermal storage loading salts are transferred from the lower temperature tank to the higher one, in a countercurrent exchanger, whose hot fluid (which cools) is the heating fluid, which is returned to the solar collector battery.
  • Said thermal load storage process continues while the power absorbed by the solar collector battery is greater than the nominal power of the plant.
  • the storage charging process ends, and the discharge process begins, in which the heat contributed to the thermodynamic cycle by the solar collector battery, is supplemented by the heat extracted from thermal storage.
  • the invention consists in configuring the solar thermal power plant with a sectorization of its battery of solar collectors and other elements, so that each sector serves a purpose of heating the thermodynamic working fluid, possibly being able to have a single sector, by identifying only one function of work fluid heating.
  • the working fluid is the same in all the sectors that the plant has, and they are connected to each other through a single working fluid circuit; unlike the heating fluid, which will have a specific current for each sector, which includes its battery of collectors and its own thermal storage system, and the pumps or compressors, valves and instrumentation detectors that also constitute the thermo-fluid circuit from each sector of the collector field; that as a circuit it also has the heat exchangers to thermally connect with the indirect thermal storage system in its load and in its discharge, and with the main heat exchanger to thermally connect with the thermodynamic working fluid circuit.
  • Each sector of the plant consists of a large thermo-fluid circuit that contains: a battery of solar radiation sensors, which will have an optical concentration part and some absorber tubes through which the heating fluid circulates and heats; - a main exchanger, which can be of direct or indirect contact, depending on the type of thermodynamic cycle used, and which transfers heat from the heating fluid to the thermodynamic working fluid, performing in that transmission the specific function of that sector of the field, which it can be of mere sensible heating, with the consequent increase of temperature of the working fluid, or of boiling of this when the function is that of steam generation; although in the case of direct contact in the exchanger, the same heating fluid becomes working fluid, leaving this component as such, and returning to it as returned working fluid, which again becomes heating fluid upon returning to go out for him conduit that communicates with the circuit that goes to the battery of solar radiation sensors; a reservoir of the heating fluid that provides fluid to the sector circuit, or extracts it, depending on the working conditions of the sector; circulators (pumps or compressors) that promote the movement of the heating fluid along the sector
  • the aforementioned high temperature storage system comprises: a heat exchanger of thermal connection of the emerging heating fluid of the solar collector battery with high temperature storage, this indirect heat contact exchanger of the heating fluid with the storage fluid, and therefore there is no mixing of the two fluids; a deposit, single or multiple, of heat-resistant material that welcomes the heat provided by the exchanger; and that as heat resistant material can use the storage fluid itself that circulates through the circuit; and that in the case of indirect internal thermal contact, it has its own indirect heat exchanger that thermally connects the storage fluid with the heat-resistant material itself; circulators (pumps or compressors) that promote the movement of the storage fluid along the thermal load circuit of the mentioned high temperature tank, and the shut-off and regulating valves that control the movement; a heat exchanger heat exchanger of high temperature storage, with indirect thermal contact of the storage fluid with the heating fluid, which emerges heated from this exchanger, to enter the main exchanger, where it is thermally connected to the working fluid; circulators (pumps or compressors) that promote the movement of indirect
  • a general or direct thermal storage system of (relatively) low temperature comprising: a reservoir of heat-resistant material that welcomes the heat provided directly by the heating fluid, either by direct heating; either by having an indirect heat exchanger that thermally connects the heating fluid with the heat-resistant material itself; a thermal load circuit, which extracts heat fluid from the main circuit of the latter, which is the one that connects the collector battery to the main exchanger, so that its heat is transferred in direct storage, returning the flow of the heating fluid downstream of the exchanger principal; a thermal discharge circuit, inverse to the previous one, that takes heat fluid after emerging from the main exchanger, and is returned, after heating as it passes through storage, upstream of the thermal discharge exchanger of the indirect storage system; the circulators (pumps or compressors) that promote the movement of the heating fluid along the thermal loading and unloading circuits of the low temperature storage, and the cutting and regulating valves that control the movement of this fluid to connect directly with The circuit of the heating fluid.
  • a substantial part of the invention is that the plant, and each of its sectors, are configured with the following operating circuits, which are determined by the opening of valves and by the activation of the pumps or circulators made in each case, as defined in each operating condition, taking into account that the position or state, by default, of the valves will be the closing one, and in the pumps Ia of inactivation: in conditions of capture of the solar irradiation with which the operation is not reached nominal, and there is no thermal energy stored in its systems, in each sector of the plant the heating fluid circulates directly from the solar collector battery to its corresponding main exchanger, through whose secondary circuit the working fluid circulates, all components being inactive of loading and thermal unloading of storage systems, and in particular the high or individual system load exchanger straight, whose secondary circuit does not circulate fluid, the operation of the exchanger being canceled for this purpose, its valves being closed, and its pumps inactive; and the valves of the loading and unloading branches of the direct low temperature thermal storage system being closed, their pumps being also inactive; in
  • valves 10 nominal temperature, the valves being open and the secondary circuit pump of the high exchanger activated; and opening the loading valves of the low temperature storage system, through whose branch, in which its pump is activated, the fluid flow rate passes
  • thermodynamic cycle of the plant 20 nominal operation of the thermodynamic cycle of the plant; the thermal storage being totally or partially filled, and being able to capture the solar irradiation that does not produce the nominal operation of the thermodynamic cycle of the plant,
  • Figure 1 shows the scheme of a sector of a helium-thermal power plant configured to work with exergetic management, in which the battery of sensors, the main exchanger and the rest of the components of the proposed invention are appreciated.
  • Figure 2 shows the scheme of the main circuit of the heating fluid in the operating mode in which it does not reach its nominal values, and the thermal storage is empty.
  • Figure 3 shows the scheme of the thermal load circuit of the storage systems, when the solar irradiation produces values of mass flow and temperature of the heating fluid above the nominal values, at the output of the collector battery. The connection part with the main exchanger is not drawn, which is the same as in the previous figure.
  • Figure 4 shows the scheme of the discharge circuit of the thermal storage systems, providing the complementary mass flow of heating fluid from the low temperature, and heating the whole flow in the exchanger that receives heat from the high temperature storage.
  • Figure 5 shows a scheme similar to that of Ia 4, but when there is no longer any solar irradiation, and no flow is provided from the collector battery.
  • Figure 6 shows a scheme of sectorization of a plant, with three sectors on the left, of preheating, boiling and overheating; plus a reheating sector on the right, and the power block of the thermodynamic cycle in the center.
  • Indirect or high temperature storage tank which in turn may have an indirect heat exchanger that thermally connects the storage fluid with the heat-resistant material itself.
  • Storage fluid recirculation pump in the indirect system load circuit 16.
  • Indirect or high temperature system discharge circuit which is the primary of the exchanger 20.
  • Low temperature storage tank which in turn can have an indirect heat exchanger that thermally connects the heating fluid with the heat-resistant material itself.
  • Mass flow rate and fluid temperature meter at the exit of the load exchanger of the high temperature storage system are Mass flow rate and fluid temperature meter at the exit of the load exchanger of the high temperature storage system.
  • Mass flow and fluid temperature meter after deviations from the loading and unloading branches of the low temperature storage system.
  • Mass flow and fluid temperature meter at the outlet of the main exchanger 28. Mass flow and fluid temperature meter at the outlet of the main exchanger.
  • Mass flow and fluid temperature meter after the return branch of the low temperature storage system, in discharge.
  • a tube and shell exchanger will be chosen against the current; in the boiling, the working fluid will be in phase change and at constant temperature, and the heating fluid will be a few degrees above, and it will be a steam generator, possibly with internal recirculation of the working fluid, to maintain a high film coefficient; in steam overheating, the film coefficient will be much lower, and The heating fluid will have to be noticeably hotter than the steam.
  • the storage fluid can be at a pressure significantly lower than that of the calorific, which can greatly facilitate the constructive aspects of the high-temperature storage system load exchanger (13) and the indirect storage tank (15), or high temperature, which in turn can have an indirect heat exchanger that thermally connects the storage fluid with the heat-resistant material itself, as well as the discharge exchanger (20), which can carry said fluid through the housing, leading to the calorific by the tubes (although in the figures it is not schematized thus, since it is the direct storage fluid that goes through the tubes).
  • this indirect storage must be of low entropy, such that the temperature extracted by the storage fluid is not reduced by a dispersion of heat in a large mass of heat-resistant storage material.
  • This type of storage can be achieved in multiple ways. For example, with two tanks of molten salts, one of base and another of heated salts, which would be heated when circulating inside the secondary circuit of the high temperature storage system load exchanger (14) (which could be in Ia housing of the high-temperature storage system load exchanger (13), even if it has been drawn from tubes inside), the heated salts of the indirect storage tank, or high temperature (15) would have a temperature lower than that of Exit the collector field at about ten degrees Celsius.
  • the heating fluid in the moments of greatest solar irradiation, could provide temperatures above the nominal in about 30 degrees Celsius or more.
  • Figure 2 shows the operative parts of the sector, in conditions of solar irradiation in which the nominal operation is not reached, and there is no thermal energy stored in its systems (for example, at the beginning of its daily regime).
  • the heating fluid circulates directly from the solar collector battery (1) to its corresponding main exchanger (2), through whose secondary circuit the working fluid circulates, for which the pump (34) of recirculation of the heating fluid in the circuit operates.
  • the valves of the loading (41 and 38) and discharge (36 and 40) branches of the direct low temperature thermal storage system are closed (see figure 1).
  • the level of solar irradiation that produces the nominal operation of the thermodynamic cycle of the plant is exceeded, the mass flow rate and the temperature of the heating fluid in each sector are above their corresponding nominal values, activating the thermal load mode of the systems storage, as shown in Figure 3.
  • the mass flow meter and fluid temperature meter at the exit of the solar collector field (1) marks those values of mass flow and temperature above of nominal, and this starts up the circulation through the secondary circuit (14) of the high temperature exchanger (13), opening the closing valves (18) of the secondary circuit of the load exchanger of the high storage system temperature (see figure 1) and starting the recirculation pump (16) of the storage fluid in the charging circuit of the indirect system.
  • the activated flow of storage fluid is adjusted so that it acquires a temperature above the nominal one, thus heating the thermal reservoir (15) of said high temperature system.
  • the transfer is adjusted so that the heating fluid leaves said exchanger precisely at nominal temperature, which is verified in the mass flow meter and fluid temperature at the outlet of the load exchanger of the high temperature storage system .
  • valves (41 and 38) (see figure 1) of the low temperature storage system are also opened, through which the mass flow of excess heating fluid over the nominal value passes.
  • the diversion of said surplus through said branch is verified by the measurements of the mass flow meter and fluid temperature (25) after the deviations of the loading and unloading branches of the low temperature storage system, which have to coincide with the nominal values. If they do not match, the states of the valves and pumps involved are modified.
  • the closing-regulation valves of the load branch of the low temperature storage system (41) and the closing-regulation of the return branch must be opened further from the low temperature storage system to the main circuit, on load (38) (see figure 1), and eventually give more power to the recirculation pump (37) of the heating fluid in the connection return between direct storage and main circuit, in storage load.
  • the thermal energy stored in the indirect (15) and direct (22) systems is increased, whose temperatures are controlled by the temperature meters of the high-temperature storage material of the high-temperature storage (32) and the temperature of the storage tank. heat-resistant material of the low temperature storage (33) respectively, which measure on the part or mass of the tank of heat-resistant material that has already been energized at that time.
  • the closing valve (36) of the return branch to the low temperature storage system (22) and the closing valve (40) of the discharge branch are opened further of the low temperature storage system, or eventually more power is given to the heat recirculation pump (35) in the return connection between the main exchanger (2) and the direct storage (22).
  • the meter (25) of mass flow and fluid temperature after deviations of the loading and unloading branches of the low temperature storage system indicates that the mass flow is nominal, but the temperature does not reach nominal, for Io that this combined flow is heated in the discharge exchanger (20) taking advantage of the heat of the high temperature storage (15), whose fluid is put into circulation when opening the shut-off valves (19) of the primary circuit of the discharge exchanger of the high temperature storage system (see figure 1) and start the recirculation pump (17) of the storage fluid in the discharge circuit of the indirect system, or high temperature, with which the movement of the fluid is regulated of that storage, so that in the meter (27) of mass flow and fluid temperature at the inlet of the main exchanger, it is verified that the temperature is the nomination to the.
  • a tank (7) that contains heating fluid, and to which part of the mass content in the circuit can be evacuated, opening The shut-off valve (9) regulating the transfer branch (8) of the heating fluid to the tank, from the circuit, or vice versa, injecting in the more fluid circuit, at more pressure, for which the pump is provided ( 12) of transfer of the heating fluid from the tank to the circuit, the valve (11) opening-regulating the transfer branch of the heating fluid (10) from the tank to the circuit being opened for this purpose.
  • Sectors such as those described, integrated by a battery of collectors, storage systems, the main exchanger and the auxiliary elements of circulation, instrumentation and flow control, are grouped, sharing the working fluid, to give rise to a thermal power plant.
  • solar with energy management aimed at its exergy optimization, of which a scheme is presented in figure 6.
  • four sectors have been represented, which conceptually, by their relative position, can be described as preheating sector (49); steam generation sector (50); overheating sector (51) and overheating sector (52).
  • the working fluid In the sector of preheating (49), the working fluid is in liquid phase, and passes through the main exchanger (2) of said sector, which will have a battery of solar collectors suitable to that temperature range, indicating that in that exchanger, the coefficient of film of the working fluid will be moderate, much smaller than the one that will have the fluid in the main exchanger (2) of the sector (50) with its battery of sensors, thermal storage systems and main exchanger, of boiling of the working fluid, because in this one there will be nucleated boiling, and its film coefficient will have very high values; which will also be higher than in the sectors where the working fluid circulates as dry steam, sector (51) with its battery of collectors, thermal storage systems and main exchanger, of overheating of the working fluid (51) or drying again in the sector of overheating of the working fluid (52).

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Abstract

The invention relates to a solar thermal power station with exergetic management of heat, in order to operate under nominal conditions for long periods of time every day. The power station is divided into sectors with different heating functions, in which each sector has its own heating fluid, but all of the sectors consecutively receive the same working fluid for the thermodynamic cycle. Each sector includes: an array of solar collectors (1), a main exchanger (2) in thermal contact with the working fluid, an indirect heat storage system and a direct heat storage system, as well as the pumps, valves and instrumentation necessary to configure each sector according to three different circuits, thereby allowing heat energy to be stored when the captured solar radiation is above the nominal value and for this heat to be used to operate the thermodynamic cycle under nominal conditions when the radiation value falls below the nominal value.

Description

CENTRAL HELIO-TÉRMICA CON GESTIÓN EXERGÉTICA DEL CALOR HELIO-THERMAL POWER STATION WITH EXERGETIC HEAT MANAGEMENT
SECTOR DE LA TÉCNICA La invención se encuadra en el campo de las centrales térmicas cuya fuente térmica es Ia radiación solar, concentrada por algunos de los posibles modos de concentración óptica, y particularmente mediante campos de colectores cilindro-parabólicos con tubo absorbedor en el eje focal, o mediante espejos de concentración de Ia radiación sobre un receptor central ubicado en una torre. Denominaremos batería de captadores solares al conjunto de elementos, sea cual sea Ia configuración, en los que se produce Ia absorción de Ia radiación solar. Estas centrales están dedicadas a Ia generación de electricidad, o de energía mecánica de rotación, mediante un ciclo termodinámico, que puede usar un ciclo tipo Rankine, con un vapor que se condense en el foco frío del ciclo, o un ciclo tipo Brayton, con un gas que no se condense, como fluido de trabajo.TECHNICAL SECTOR The invention falls within the field of thermal power plants whose thermal source is solar radiation, concentrated by some of the possible modes of optical concentration, and particularly by means of fields of parabolic trough collectors with absorber tube in the focal axis , or through mirrors of concentration of the radiation on a central receiver located in a tower. We will designate a battery of solar collectors to the set of elements, whatever the configuration, in which the absorption of solar radiation occurs. These plants are dedicated to the generation of electricity, or mechanical rotation energy, by means of a thermodynamic cycle, which can be used by a Rankine type cycle, with a vapor that condenses in the cold focus of the cycle, or a Brayton type cycle, with a gas that does not condense, as a working fluid.
La invención se refiere al modo de estructurar los diversos componentes de Ia central, para que ésta aproveche al máximo Ia capacidad de captación de energía solar que tenga su batería de captadores solares, en función del tipo de ciclo y de las prestaciones nominales del mismo. Respecto de esto último, se tiene especialmente en cuenta que Ia turbina del ciclo tendrá su mejor rendimiento cuando el fluido de trabajo entre en ella con Ia temperatura, presión y caudal nominales.The invention relates to the way of structuring the various components of the plant, so that it takes full advantage of the solar energy collection capacity of its solar collector battery, depending on the type of cycle and its nominal performance. Regarding the latter, it is especially taken into account that the turbine of the cycle will have its best performance when the working fluid enters it with the nominal temperature, pressure and flow.
En particular Ia invención tiene en cuenta Ia variación de Ia potencia de Ia irradiación solar, tanto con carácter diario como estacional, y Ia pertinencia, por tanto, de disponer de un almacenamiento térmico, que a su vez puede ser de diversos tipos, pero que se ha de ajustar adecuadamente para que, durante el mayor tiempo posible, Ia central funcione en condiciones nominales.In particular, the invention takes into account the variation of the power of solar irradiation, both daily and seasonal, and the relevance, therefore, of having a thermal storage, which in turn can be of various types, but which It must be adjusted properly so that, for as long as possible, the plant operates in nominal conditions.
ANTECEDENTES DE LA INVENCIÓNBACKGROUND OF THE INVENTION
Existe una amplia variedad de sistemas para estructurar las centrales solares. Una alternativa esencial es si se utiliza el mismo fluido en el ciclo termodinámico y en Ia batería de captadores solares, entendiendo por ésta el conjunto de elementos donde se produce Ia absorción de Ia radiación solar. En esta invención se puede utilizar el mismo fluido, o fluidos distintos, para Ia batería de captadores y para el ciclo, en función del tipo de ciclo especialmente. En este documento designaremos por fluido calorífero al que extrae el calor de Ia batería de captadores solares, y por fluido de trabajo al que evoluciona en el ciclo termodinámico.There is a wide variety of systems to structure solar power plants. An essential alternative is if the same fluid is used in the thermodynamic cycle and in the solar collector battery, this being understood as the set of elements where the absorption of solar radiation occurs. In this invention the same fluid, or different fluids, can be used for the collector battery and for the cycle, depending on the type of cycle especially. In this document we will designate by heat fluid the one that extracts the heat from the solar collector battery, and by working fluid to the one that evolves in the thermodynamic cycle.
Por ejemplo, en Ia tecnología convencional actual de colectores cilindro- parabólicos, el fluido calorífero, es un aceite térmico, como el Therminol VP; mientras que el fluido de trabajo del ciclo termodinámico es agua, que sigue un ciclo de Rankine, donde se encuentran típicamente tres niveles de actuación térmica; el de precalentamiento del agua; el de ebullición de ésta; y el de sobrecalentamiento. En el caso de receptor en torre, el fluido calorífero suele ser una sal fundida; usando típicamente agua como fluido de trabajo.For example, in the current conventional technology of parabolic trough collectors, the heating fluid is a thermal oil, such as the Therminol VP; while the working fluid of the thermodynamic cycle is water, which follows a Rankine cycle, where three levels of thermal performance are typically found; water preheating; the boiling of it; and overheating. In the case of a tower receiver, the heating fluid is usually a molten salt; typically using water as a working fluid.
Una alternativa es utilizar gas (no condensable) como fluido de trabajo (ciclo Brayton), y en tal caso el gas puede utilizarse así mismo como fluido calorífero. En este caso, el gas se ha de comprimir hasta Ia presión nominal de alta, y hacerse circular por Ia batería de captadores solares para que se caliente, enviándose a Ia turbina de gas para su expansión, con Ia consiguiente conversión en energía mecánica.An alternative is to use gas (non-condensable) as a working fluid (Brayton cycle), and in this case the gas can also be used as a heating fluid. In this case, the gas has to be compressed to the nominal high pressure, and circulated through the solar collector battery so that it is heated, being sent to the gas turbine for expansion, with the consequent conversion into mechanical energy.
Como condicionante común a todas las centrales solares térmicas, hay que señalar de nuevo Ia variación de Ia potencia solar. En un día soleado habitual, Ia batería de captadores solares irá recibiendo y absorbiendo cada vez mayor potencia térmica, tal como el sol se alce en su órbita diurna, y de igual manera se irán calentando el fluido calorífero y el fluido de trabajo; hasta que éste alcance el mínimo técnico de funcionamiento de Ia turbina, que es cuando comienza a funcionar verdaderamente Ia central. A partir de ahí va aumentando Ia potencia, gracias al aumento de temperatura en Ia batería de captadores y en los fluidos, que van además aproximando sus caudales másicos a los valores nominales correspondientes. A ellos, y a las temperaturas nominales, se llega cuando Ia irradiación solar alcanza el valor para el que se ha diseñado nominalmente Ia planta; pero Ia potencia absorbida en Ia batería de captadores sigue ascendiendo, porque Ia máxima potencia alcanzable por Ia batería de captadores de Ia central es mayor que Ia nominal, especialmente en días de primavera y, sobre todo, verano. Llegada a esa situación, Ia tecnología convencional es Ia de enviar Ia potencia térmica excedente a un almacenamiento térmico. Concretamente Io que se realiza en el estado actual del arte es Io siguiente: se sigue aumentando el caudal de Ia batería de captadores, y una vez que se ha llegado a temperatura nominal, se desvía el excedente de caudal de fluido calorífero a un intercambiador con el almacenamiento térmico, que típicamente consiste en dos tanques de sales fundidas, uno a temperatura menor, y otro a temperatura mayor. En el proceso de carga térmica del almacenamiento, se transfieren sales del tanque de menor temperatura al de mayor, en un intercambiador a contracorriente, cuyo fluido caliente (que se enfría) es el fluido calorífero, que se devuelve a Ia batería de captadores solares. Dicho proceso de carga térmica del almacenamiento prosigue mientras Ia potencia absorbida por Ia batería de captadores solares es mayor que Ia potencia nominal de Ia planta. Cuando esta última, por declinar Ia potencia solar, es rebasada hacia abajo, el proceso de carga del almacenamiento acaba, y da comienzo el proceso de descarga, en el cual el calor aportado al ciclo termodinámico por Ia batería de captadores solares, se suplementa por el calor extraído del almacenamiento térmico. Para esto, las funciones de los fluidos se alternan en el intercambiador a contracorriente antes mencionado, y las sales fundidas son ahora el fluido caliente, que se enfría al tiempo que es transferido del tanque de alta temperatura al de baja, calentándose el fluido calorífero que va a alimentar térmicamente al ciclo termodinámico. Ahora bien, en ambos procesos de intercambio de calor, en Ia carga y en Ia descarga térmica del almacenamiento, se pierde temperatura, por Io que el fluido calorífero calentado en Ia fase de extracción de calor del almacenamiento (descarga) no llega a su temperatura nominal, que es para Ia cual funciona Ia turbina en sus mejores prestaciones. Análogamente ocurre con otros tipos de almacenamientos convencionales, tales como los que almacenan directamente vapor a presión, o calor en lechos sólidos, de tipo cerámico, pues tanto en Ia carga como en Ia descarga se produce una disminución de la calidad de Ia energía térmica disponible. Es decir, en ese proceso de gestión del calor se ha producido un deterioro exergético, y de hecho Ia turbina deja de funcionar nominalmente en esa fase de aprovechamiento del calor almacenado. El problema, a resolver con Ia invención, es posibilitar que ese funcionamiento siga siendo nominal, durante el tiempo en que haya energía térmica en el almacenamiento. DESCRIPCIÓN DE LA INVENCIÓNAs a common conditioner for all solar thermal power plants, it should be noted again the variation of solar power. On a usual sunny day, the battery of solar collectors will receive and absorb increasing thermal power, just as the sun rises in its daytime orbit, and in the same way the heating fluid and the working fluid will be heated; until it reaches the minimum technical operation of the turbine, which is when the plant truly begins to function. From there, the power increases, thanks to the increase in temperature in the collector battery and in the fluids, which also approximate their mass flow rates to the corresponding nominal values. They, and at the nominal temperatures, are reached when the solar irradiation reaches the value for which the plant has been nominally designed; but the power absorbed in the battery of sensors continues to rise, because the maximum power attainable by the battery of sensors of the plant is greater than the nominal, especially in spring days and, especially, summer. At this situation, conventional technology is to send the excess thermal power to a thermal storage. Specifically, what is done in the current state of the art is as follows: the flow of the collector battery is still increasing, and once the nominal temperature has been reached, the excess heat flow rate is diverted to an exchanger with thermal storage which It typically consists of two tanks of molten salts, one at a lower temperature, and another at a higher temperature. In the process of thermal storage loading, salts are transferred from the lower temperature tank to the higher one, in a countercurrent exchanger, whose hot fluid (which cools) is the heating fluid, which is returned to the solar collector battery. Said thermal load storage process continues while the power absorbed by the solar collector battery is greater than the nominal power of the plant. When the latter, by declining the solar power, is exceeded downwards, the storage charging process ends, and the discharge process begins, in which the heat contributed to the thermodynamic cycle by the solar collector battery, is supplemented by the heat extracted from thermal storage. For this, the functions of the fluids are alternated in the countercurrent exchanger mentioned above, and the molten salts are now the hot fluid, which is cooled while being transferred from the high temperature tank to the low one, the heating fluid that is heated It will thermally feed the thermodynamic cycle. However, in both heat exchange processes, in the load and in the thermal discharge of the storage, temperature is lost, so that the heating fluid heated in the heat extraction phase of the storage (discharge) does not reach its temperature nominal, which is for which the turbine works in its best performance. Similarly, it occurs with other types of conventional storage, such as those that directly store pressurized steam, or heat in solid beds, of a ceramic type, since both the load and the discharge produce a decrease in the quality of the available thermal energy . That is, in this heat management process there has been an exergetic deterioration, and in fact the turbine stops working nominally in that phase of utilizing the stored heat. The problem, to be solved with the invention, is to enable that operation to remain nominal, for as long as there is thermal energy in the storage. DESCRIPTION OF THE INVENTION
La invención consiste en configurar Ia central termosolar con una sectorización de su batería de captadores solares y otros elementos, de modo que cada sector atienda una finalidad de calentamiento del fluido de trabajo termodinámico, pudiendo eventualmente haber un único sector, por identificarse sólo una función de calentamiento del fluido de trabajo. En todo caso, el fluido de trabajo es el mismo en todos los sectores que tenga Ia central, y están conectados entre sí a través de un único circuito de fluido de trabajo; al contrario que el fluido calorífero, que tendrá una corriente específica para cada sector, Io cual incluye su batería de captadores y su propio sistema de almacenamiento térmico, y las bombas o compresores, válvulas y detectores de instrumentación que constituyen también el circuito termo-fluido de cada sector del campo de colectores; que como circuito cuenta también con los intercambiadores de calor para conectarse térmicamente con el sistema de almacenamiento térmico indirecto en su carga y en su descarga, y con el intercambiador principal de calor para conectarse térmicamente con el circuito del fluido de trabajo termodinámico. Es fundamental a este respecto establecer un criterio técnico sobre cuando se han de disponer sectores independientes para dos funciones de calentamiento distintas en Ia misma central, y este criterio es que se dispondrán sectores independientes para dos funciones de calentamiento distintas, cuando cualquiera de los valores de las dos magnitudes relevantes, que a continuación se indican, difieran entre funciones de calentamiento distintas consecutivas en más de un 25 %, siendo estas magnitudes relevantes el factor de concentración solar y el coeficiente global de transmisión de calor entre Ia cubierta absorbente de Ia batería de captadores solares y el fluido calorífero.The invention consists in configuring the solar thermal power plant with a sectorization of its battery of solar collectors and other elements, so that each sector serves a purpose of heating the thermodynamic working fluid, possibly being able to have a single sector, by identifying only one function of work fluid heating. In any case, the working fluid is the same in all the sectors that the plant has, and they are connected to each other through a single working fluid circuit; unlike the heating fluid, which will have a specific current for each sector, which includes its battery of collectors and its own thermal storage system, and the pumps or compressors, valves and instrumentation detectors that also constitute the thermo-fluid circuit from each sector of the collector field; that as a circuit it also has the heat exchangers to thermally connect with the indirect thermal storage system in its load and in its discharge, and with the main heat exchanger to thermally connect with the thermodynamic working fluid circuit. It is essential in this regard to establish a technical criterion on when independent sectors are to be provided for two different heating functions in the same plant, and this criterion is that independent sectors will be available for two different heating functions, when any of the values of The two relevant quantities, which are indicated below, differ between different consecutive heating functions by more than 25%, these relevant quantities being the solar concentration factor and the overall heat transmission coefficient between the absorbent cover of the battery of solar collectors and heating fluid.
Cada sector de Ia central consiste en un gran circuito termo-fluido que contiene: una batería de captadores de radiación solar, que tendrá una parte de concentración óptica y unos tubos absorbedores por cuyo interior circula y se calienta el fluido calorífero; - un intercambiador principal, que puede ser de contacto directo o indirecto, según el tipo de ciclo termodinámico empleado, y que transfiere el calor del fluido calorífero al fluido de trabajo termodinámico, efectuando en esa transmisión Ia función específica de ese sector del campo, que puede ser de mero calentamiento sensible, con el consiguiente aumento de temperatura del fluido de trabajo, o de ebullición de éste cuando Ia función es Ia de generación de vapor; aunque en el caso de contacto directo en el intercambiador, el mismo fluido calorífero pasa a ser fluido de trabajo, saliendo como tal de este componente, y volviendo a él como fluido de trabajo retornado, que pasa a ser de nuevo fluido calorífero al volver a salir por el conducto que comunica con el circuito que va a Ia batería de captadores de Ia radiación solar; un depósito del fluido calorífero que aporta fluido al circuito del sector, o Io extrae, en función de las condiciones de trabajo del sector; los circuladores (bombas o compresores) que propician el movimiento del fluido calorífero a Io largo del circuito del sector, y las válvulas de corte y de regulación que controlan ese movimiento; - un sistema de almacenamiento indirecto, o de alta temperatura, entendiendo por esta denominación que está por encima de Ia temperatura nominal del fluido calorífero de ese sector, es decir, Ia temperatura para alimentar nominalmente el intercambiador principal de conexión térmica con el fluido de trabajo, especificándose el contenido estructural de este sistema más adelante, aunque cabe señalar ahora que tiene su propio fluido interior, que no se mezcla con el fluido calorífero, aunque puede ser de Ia misma sustancia; un sistema de almacenamiento térmico general, o directo, de (relativamente) baja temperatura, entendiendo por esta denominación que está por debajo de Ia temperatura nominal del fluido calorífero de ese sector, coincidiendo en este caso el fluido primario del almacenamiento con el propio fluido calorífero, especificándose el contenido estructural de este sistema más adelante.Each sector of the plant consists of a large thermo-fluid circuit that contains: a battery of solar radiation sensors, which will have an optical concentration part and some absorber tubes through which the heating fluid circulates and heats; - a main exchanger, which can be of direct or indirect contact, depending on the type of thermodynamic cycle used, and which transfers heat from the heating fluid to the thermodynamic working fluid, performing in that transmission the specific function of that sector of the field, which it can be of mere sensible heating, with the consequent increase of temperature of the working fluid, or of boiling of this when the function is that of steam generation; although in the case of direct contact in the exchanger, the same heating fluid becomes working fluid, leaving this component as such, and returning to it as returned working fluid, which again becomes heating fluid upon returning to go out for him conduit that communicates with the circuit that goes to the battery of solar radiation sensors; a reservoir of the heating fluid that provides fluid to the sector circuit, or extracts it, depending on the working conditions of the sector; circulators (pumps or compressors) that promote the movement of the heating fluid along the sector circuit, and the shut-off and regulating valves that control that movement; - an indirect or high temperature storage system, meaning that this designation is above the nominal temperature of the heating fluid of that sector, that is, the temperature to nominally feed the main heat exchanger with the working fluid , specifying the structural content of this system later, although it should now be noted that it has its own internal fluid, which does not mix with the heating fluid, although it may be of the same substance; a general, or direct, thermal storage system of (relatively) low temperature, this denomination being understood to be below the nominal temperature of the heating fluid of that sector, in this case the primary storage fluid coinciding with the heating fluid itself , specifying the structural content of this system later.
El antedicho sistema de almacenamiento de alta temperatura, o almacenamiento indirecto, comprende: un intercambiador de calor de conexión térmica del fluido calorífero emergente de Ia batería de captadores solares con el almacenamiento de alta temperatura, siendo este intercambiador de contacto térmico indirecto del fluido calorífero con el fluido del almacenamiento, y no habiendo por tanto mezcla alguna de los dos fluidos; un depósito, simple o múltiple, de material termorresistente que acoge el calor aportado por el intercambiador; y que como material termorresistente puede usar al propio fluido del almacenamiento que circula por el circuito; y que en el caso de contacto térmico interno indirecto, tiene su propio intercambiador de calor indirecto que conecta térmicamente el fluido del almacenamiento con el material termorresistente en sí; los circuladores (bombas o compresores) que propician el movimiento del fluido del almacenamiento a Io largo del circuito de carga térmica del depósito mencionado de alta temperatura, y las válvulas de corte y de regulación que controlan el movimiento; un intercambiador de calor de descarga térmica del almacenamiento de alta temperatura, con contacto térmico indirecto del fluido del almacenamiento con el fluido calorífero, que emerge calentado de este intercambiador, para entrar en el intercambiador principal, donde está conectado térmicamente con el fluido de trabajo; los circuladores (bombas o compresores) que propician el movimiento del fluido del almacenamiento indirecto a Io largo del circuito de descarga del almacenamiento de alta temperatura, y las válvulas de corte y de regulación que controlan el movimiento de su fluido para conectarse térmicamente con el fluido calorífero a través del intercambiador de descarga descrito en el párrafo anterior. Un sistema de almacenamiento térmico general o directo, de (relativamente) baja temperatura que comprende: un depósito de material termorresistente que acoge el calor aportado directamente por el fluido calorífero, bien por calentamiento directo; bien por disponer de un intercambiador de calor indirecto que conecte térmicamente el fluido calorífero con el material termorresistente en sí; un circuito de carga térmica, que extrae fluido calorífero del circuito principal de éste, que es el que conecta Ia batería de captadores con el intercambiador principal, para que ceda su calor en el almacenamiento directo, devolviendo el caudal del fluido calorífero aguas abajo del intercambiador principal; un circuito de descarga térmica, inverso al anterior, que toma fluido calorífero tras emerger del intercambiador principal, y es devuelto, tras calentarse a su paso por el almacenamiento, aguas arriba del intercambiador de descarga térmica del sistema de almacenamiento indirecto; los circuladores (bombas o compresores) que propician el movimiento del fluido calorífero a Io largo de los circuitos de carga y descarga térmica del almacenamiento de baja temperatura, y las válvulas de corte y de regulación que controlan el movimiento de este fluido para conectarse directamente con el circuito del fluido calorífero.The aforementioned high temperature storage system, or indirect storage, comprises: a heat exchanger of thermal connection of the emerging heating fluid of the solar collector battery with high temperature storage, this indirect heat contact exchanger of the heating fluid with the storage fluid, and therefore there is no mixing of the two fluids; a deposit, single or multiple, of heat-resistant material that welcomes the heat provided by the exchanger; and that as heat resistant material can use the storage fluid itself that circulates through the circuit; and that in the case of indirect internal thermal contact, it has its own indirect heat exchanger that thermally connects the storage fluid with the heat-resistant material itself; circulators (pumps or compressors) that promote the movement of the storage fluid along the thermal load circuit of the mentioned high temperature tank, and the shut-off and regulating valves that control the movement; a heat exchanger heat exchanger of high temperature storage, with indirect thermal contact of the storage fluid with the heating fluid, which emerges heated from this exchanger, to enter the main exchanger, where it is thermally connected to the working fluid; circulators (pumps or compressors) that promote the movement of indirect storage fluid along the high temperature storage discharge circuit, and the shut-off and regulating valves that control the movement of its fluid to thermally connect with the fluid heat exchanger through the discharge exchanger described in the previous paragraph. A general or direct thermal storage system of (relatively) low temperature comprising: a reservoir of heat-resistant material that welcomes the heat provided directly by the heating fluid, either by direct heating; either by having an indirect heat exchanger that thermally connects the heating fluid with the heat-resistant material itself; a thermal load circuit, which extracts heat fluid from the main circuit of the latter, which is the one that connects the collector battery to the main exchanger, so that its heat is transferred in direct storage, returning the flow of the heating fluid downstream of the exchanger principal; a thermal discharge circuit, inverse to the previous one, that takes heat fluid after emerging from the main exchanger, and is returned, after heating as it passes through storage, upstream of the thermal discharge exchanger of the indirect storage system; the circulators (pumps or compressors) that promote the movement of the heating fluid along the thermal loading and unloading circuits of the low temperature storage, and the cutting and regulating valves that control the movement of this fluid to connect directly with The circuit of the heating fluid.
Parte sustancial de Ia invención es que Ia central, y cada uno de sus sectores, se configuran con los siguientes circuitos de funcionamiento, que se determinan por Ia apertura de válvulas y por Ia activación de las bombas o circuladores realizadas en cada caso, según se define en cada condición operativa, teniendo en cuenta que Ia posición o estado, por defecto, de las válvulas será Ia de cierre, y en las bombas Ia de inactivación: en condiciones de captación de Ia irradiación solar con las que no se alcanza el funcionamiento nominal, y no queda energía térmica almacenada en sus sistemas, en cada sector de Ia central el fluido calorífero circula directamente desde Ia batería de captadores solares a su intercambiador principal correspondiente, por cuyo circuito secundario circula el fluido de trabajo, estando inactivos todos los componentes de carga y descarga térmica de los sistemas de almacenamiento, y en particular el intercambiador de carga del sistema de alta o indirecto, por cuyo circuito secundario no circula fluido, estando el funcionamiento del intercambiador anulado a tales efectos, estando sus válvulas cerradas, y sus bombas inactivas; y estando cerradas las válvulas de los ramales de carga y descarga del sistema directo de almacenamiento térmico de baja temperatura, estando además inactivas sus bombas; en condiciones en las que se ha superado el nivel de captación solar que produce el funcionamiento nominal del ciclo termodinámico de Ia central, el caudal másico y Ia temperatura del fluido calorífero a Ia salida de Ia batería de captadores solares de cada sector van por encima de sus valores nominales correspondientes, y se activa el modo de carga térmica de los sistemas de almacenamiento, estableciéndose Ia circulación por el circuito secundario del 5 intercambiador de alta temperatura, por Io que a Ia salida del mismo, el fluido del almacenamiento adquiere temperatura por encima de Ia nominal, calentándose así el depósito térmico de dicho sistema de alta temperatura, saliendo por el circuito primario de dicho intercambiador el fluido calorífero aA substantial part of the invention is that the plant, and each of its sectors, are configured with the following operating circuits, which are determined by the opening of valves and by the activation of the pumps or circulators made in each case, as defined in each operating condition, taking into account that the position or state, by default, of the valves will be the closing one, and in the pumps Ia of inactivation: in conditions of capture of the solar irradiation with which the operation is not reached nominal, and there is no thermal energy stored in its systems, in each sector of the plant the heating fluid circulates directly from the solar collector battery to its corresponding main exchanger, through whose secondary circuit the working fluid circulates, all components being inactive of loading and thermal unloading of storage systems, and in particular the high or individual system load exchanger straight, whose secondary circuit does not circulate fluid, the operation of the exchanger being canceled for this purpose, its valves being closed, and its pumps inactive; and the valves of the loading and unloading branches of the direct low temperature thermal storage system being closed, their pumps being also inactive; in conditions in which the level of solar collection that produces the nominal operation of the thermodynamic cycle of the plant, the mass flow and the temperature of the heating fluid at the exit of the battery of the battery has been exceeded solar collectors of each sector go above their corresponding nominal values, and the thermal load mode of the storage systems is activated, the circulation being established by the secondary circuit of the high temperature exchanger, so that at the exit of the same , the storage fluid acquires a temperature above the nominal one, thus heating the thermal reservoir of said high temperature system, the heat fluid flowing out of the primary circuit of said exchanger to
10 temperatura nominal, estando abiertas las válvulas y activada Ia bomba del circuito secundario del intercambiador de alta; y abriéndose las válvulas de carga del sistema de almacenamiento de baja temperatura, a través de cuyo ramal, en el que está activada su bomba, pasa el caudal de fluido10 nominal temperature, the valves being open and the secondary circuit pump of the high exchanger activated; and opening the loading valves of the low temperature storage system, through whose branch, in which its pump is activated, the fluid flow rate passes
15 calorífero excedente sobre el valor nominal, para volver a Ia batería de captadores solares; llegando por el circuito principal, al intercambiador principal, exactamente el caudal nominal de fluido calorífero, con Ia temperatura nominal, Io cual se verifica por los medidores correspondientes, manteniéndose así el15 calorific excess over the nominal value, to return to the solar collector battery; arriving through the main circuit, to the main exchanger, exactly the nominal flow rate of heating fluid, with the nominal temperature, which is verified by the corresponding meters, thus maintaining the
20 funcionamiento nominal del ciclo termodinámico de Ia central; estando llenos total o parcialmente los almacenamientos térmicos, y estando en condiciones de captación de Ia irradiación solar que no llega a producir el funcionamiento nominal del ciclo termodinámico de Ia central,20 nominal operation of the thermodynamic cycle of the plant; the thermal storage being totally or partially filled, and being able to capture the solar irradiation that does not produce the nominal operation of the thermodynamic cycle of the plant,
25 los valores de caudal másico y temperatura del fluido calorífero a Ia salida de Ia batería de captadores solares son insuficientes, al estar por debajo de los valores nominales correspondientes, y en tal caso se activan los sistemas de descarga térmica de ambos almacenamientos, aportándose desde el sistema directo,25 the values of mass flow and temperature of the heating fluid at the exit of the solar collector battery are insufficient, being below the corresponding nominal values, and in this case the thermal discharge systems of both storage are activated, contributing from the direct system,
30 o de baja temperatura, el caudal másico de fluido calorífero que falta para completar hasta el valor nominal el caudal másico aportado por Ia batería de captadores, para Io cual se activa Ia bomba y se abren las válvulas de descarga del almacenamiento directo; y se calienta el caudal conjunto de fluido calorífero hasta30 or low temperature, the mass flow of heating fluid that is missing to complete up to the nominal value the mass flow provided by the collector battery, for which the pump is activated and the direct storage discharge valves are opened; and the combined flow of heating fluid is heated to
35 el valor nominal de temperatura, por Ia acción del intercambiador de descarga térmica del almacenamiento indirecto o de alta temperatura, para Io cual se abren sus válvulas y se activa su bomba; y por Io cual, Ia mezcla de los caudales másicos, aportados desde Ia batería de captadores solares y desde el almacenamiento directo, al intercambiador principal, tiene no sólo el caudal másico nominal, sino Ia temperatura nominal, Io que se verifica por el medidor correspondiente. BREVE DESCRIPCIÓN DE LAS FIGURAS35 the nominal value of temperature, by the action of the heat discharge exchanger of indirect or high storage temperature, for which its valves are opened and its pump is activated; and by which, the mixture of the mass flows, contributed from the battery of solar collectors and from the direct storage, to the main exchanger, has not only the nominal mass flow, but the nominal temperature, which is verified by the corresponding meter . BRIEF DESCRIPTION OF THE FIGURES
La figura 1 muestra el esquema de un sector de una central helio-térmica configurada para funcionar con gestión exergética, en el que se aprecia Ia batería de captadores, el intercambiador principal y el resto de los componentes de Ia invención propuesta.Figure 1 shows the scheme of a sector of a helium-thermal power plant configured to work with exergetic management, in which the battery of sensors, the main exchanger and the rest of the components of the proposed invention are appreciated.
La figura 2 muestra el esquema del circuito principal del fluido calorífero en el modo de funcionamiento en el que no llega a sus valores nominales, y los almacenamientos térmicos están vacíos. La figura 3 muestra el esquema del circuito de carga térmica de los sistemas de almacenamiento, cuando Ia irradiación solar produce valores de caudal másico y temperatura del fluido calorífero por encima de los valores nominales, a Ia salida de Ia batería de captadores. No se dibuja Ia parte de conexión con el intercambiador principal, que es igual que en Ia figura anterior. La figura 4 muestra el esquema del circuito de descarga de los sistemas de almacenamiento térmico, aportándose el caudal másico complementario de fluido calorífero desde el de baja temperatura, y calentándose el caudal conjunto en el intercambiador que recibe calor del almacenamiento de alta temperatura.Figure 2 shows the scheme of the main circuit of the heating fluid in the operating mode in which it does not reach its nominal values, and the thermal storage is empty. Figure 3 shows the scheme of the thermal load circuit of the storage systems, when the solar irradiation produces values of mass flow and temperature of the heating fluid above the nominal values, at the output of the collector battery. The connection part with the main exchanger is not drawn, which is the same as in the previous figure. Figure 4 shows the scheme of the discharge circuit of the thermal storage systems, providing the complementary mass flow of heating fluid from the low temperature, and heating the whole flow in the exchanger that receives heat from the high temperature storage.
La figura 5 muestra un esquema similar al de Ia 4, pero cuando ya no hay nada de irradiación solar, y no se aporta caudal desde Ia batería de captadores.Figure 5 shows a scheme similar to that of Ia 4, but when there is no longer any solar irradiation, and no flow is provided from the collector battery.
La figura 6 muestra un esquema de sectorización de una central, con tres sectores a Ia izquierda, de precalentamiento, ebullición y sobrecalentamiento; más un sector de recalentamiento a Ia derecha, y el bloque de potencia del ciclo termodinámico en el centro. MODOS PREFERENTES DE REALIZACIÓN DE LA INVENCIÓNFigure 6 shows a scheme of sectorization of a plant, with three sectors on the left, of preheating, boiling and overheating; plus a reheating sector on the right, and the power block of the thermodynamic cycle in the center. PREFERRED EMBODIMENTS OF THE INVENTION
Para facilitar Ia comprensión de las materializaciones preferentes de Ia invención, a continuación se describen las referencias numéricas que aparecen en las figuras y describen los elementos relevantes de las realizaciones preferentes que se describen a continuación: 1. Batería de captadores de Ia radiación solar (captadores solares).To facilitate the understanding of the preferred embodiments of the invention, the numerical references that appear in the figures are described below and describe the relevant elements of the preferred embodiments described below: 1. Battery of solar radiation collectors (collectors solar).
2. Intercambiador principal, entre el fluido calorífero y el fluido de trabajo.2. Main exchanger, between the heating fluid and the job.
3. Entrada del fluido calorífero al ¡ntercambiador principal.3. Inlet of the heating fluid to the main exchanger.
4. Salida del fluido calorífero del intercambiador principal.4. Output of the heat exchanger fluid from the main exchanger.
5. Entrada del fluido de trabajo termodinámico al intercambiador principal.5. Inlet of the thermodynamic working fluid to the main exchanger.
6. Salida del fluido de trabajo termodinámico del intercambiador principal.6. Output of the thermodynamic working fluid from the main exchanger.
7. Depósito de fluido calorífero. δ. Ramal de trasiego del fluido calorífero al depósito, desde el circuito.7. Heat fluid reservoir. δ. Branch of transfer of the heating fluid to the tank, from the circuit.
9. Válvula de cierre-regulación del ramal 8.9. Branch check valve-regulation 8.
10. Ramal de trasiego del fluido calorífero desde el depósito al circuito.10. Transfer branch of the heating fluid from the tank to the circuit.
11. Válvula de cierre-regulación del ramal 10. 12. Bomba de trasiego del fluido calorífero desde el depósito al circuito.11. Shut-off valve of the branch 10. 12. Transfer pump of the heating fluid from the tank to the circuit.
13. I ntercambiador de carga del sistema de almacenamiento de alta temperatura.13. High load storage system load exchanger.
14. Circuito secundario del intercambiador de carga del sistema de almacenamiento de alta temperatura.14. Secondary circuit of the high temperature storage system load exchanger.
15. Depósito del almacenamiento indirecto, o de alta temperatura, que a su vez puede tener un intercambiador de calor indirecto que conecte térmicamente el fluido del almacenamiento con el material termorresistente en sí. 16. Bomba de recirculación del fluido del almacenamiento en el circuito de carga del sistema indirecto.15. Indirect or high temperature storage tank, which in turn may have an indirect heat exchanger that thermally connects the storage fluid with the heat-resistant material itself. 16. Storage fluid recirculation pump in the indirect system load circuit.
17. Bomba de recirculación del fluido del almacenamiento en el circuito de descarga del sistema indirecto, o de alta temperatura.17. Storage fluid recirculation pump in the discharge circuit of the indirect system, or high temperature.
18. Válvulas de cierre-regulación del circuito secundario del intercambiador de carga del sistema de almacenamiento de alta temperatura.18. Shut-off valves for the secondary circuit of the high temperature storage system load exchanger.
19. Válvulas de cierre-regulación del circuito primario del intercambiador de descarga del sistema de almacenamiento de alta temperatura. 20. Intercambiador de descarga del sistema indirecto de almacenamiento térmico, circulando por su circuito primario el fluido del sistema de alta temperatura, y el fluido calorífero por el secundario.19. Shut-off valves of the primary circuit of the high temperature storage system discharge exchanger. 20. Discharge exchanger of the indirect thermal storage system, circulating through its primary circuit the fluid of the high temperature system, and the heating fluid by the secondary.
21. Circuito de descarga del sistema indirecto, o de alta temperatura, que es el primario del intercambiador 20.21. Indirect or high temperature system discharge circuit, which is the primary of the exchanger 20.
22. Depósito del almacenamiento de baja temperatura, que a su vez puede tener un intercambiador de calor indirecto que conecte térmicamente el fluido calorífero con el material termorresistente en sí.22. Low temperature storage tank, which in turn can have an indirect heat exchanger that thermally connects the heating fluid with the heat-resistant material itself.
23. Medidor de caudal másico y de temperatura del fluido a Ia salida del campo de colectores solares 1.23. Mass flow and fluid temperature meter at the exit of the solar collector field 1.
24. Medidor de caudal másico y de temperatura del fluido a Ia salida del intercambiador de carga del sistema de almacenamiento de alta temperatura.24. Mass flow rate and fluid temperature meter at the exit of the load exchanger of the high temperature storage system.
25. Medidor de caudal másico y de temperatura del fluido tras las desviaciones de los ramales de carga y descarga del sistema de almacenamiento de baja temperatura. 26. Medidor de caudal másico y de temperatura del fluido en Ia inyección de descarga del sistema de almacenamiento térmico directo.25. Mass flow and fluid temperature meter after deviations from the loading and unloading branches of the low temperature storage system. 26. Mass flow rate and fluid temperature meter in the discharge injection of the direct thermal storage system.
27. Medidor de caudal másico y de temperatura del fluido a Ia entrada del intercambiador principal.27. Mass flow rate and fluid temperature meter at the main exchanger inlet.
28. Medidor de caudal másico y de temperatura del fluido a Ia salida del intercambiador principal.28. Mass flow and fluid temperature meter at the outlet of the main exchanger.
29. Medidor de caudal másico y de temperatura del fluido tras Ia desviación del ramal de evacuación al depósito de fluido calorífero.29. Mass flow and fluid temperature meter after the diversion of the evacuation branch to the heating fluid reservoir.
30. Medidor de caudal másico y de temperatura del fluido tras el ramal de retorno del sistema de almacenamiento de baja temperatura, en descarga.30. Mass flow and fluid temperature meter after the return branch of the low temperature storage system, in discharge.
31. Medidor de caudal másico y de temperatura del fluido a Ia entrada de Ia batería de captadores solares 1.31. Mass flow rate and fluid temperature meter at the inlet of the solar collector battery 1.
32. Medidor de temperatura del depósito de material termorresistente del almacenamiento de alta temperatura. 33. Medidor de temperatura del depósito de material termorresistente del almacenamiento de baja temperatura.32. Temperature gauge of the high-temperature storage material storage tank. 33. Temperature gauge of the low temperature storage heat-resistant material tank.
34. Bomba de recirculación del fluido calorífero en el circuito principal de conexión entre el intercambiador principal 2 y Ia batería de captadores34. Recirculation pump of the heating fluid in the main connection circuit between the main exchanger 2 and the collector battery
1. 35. Bomba de recirculación del fluido calorífero en el retorno de conexión entre el intercambiador principal 2 y el almacenamiento directo 22.1. 35. Heat fluid recirculation pump in the return connection between main exchanger 2 and direct storage 22
36. Válvula de cierre-regulación del ramal de retorno al sistema de almacenamiento de baja temperatura 22.36. Shut-off valve regulating the return branch to the low temperature storage system 22.
37. Bomba de recirculación del fluido calorífero en el retorno de conexión entre el almacenamiento directo y el circuito principal, en carga del almacenamiento.37. Recirculation pump of the heating fluid in the return connection between the direct storage and the main circuit, in charge of the storage.
38. Válvula de cierre-regulación del ramal de retorno del sistema de almacenamiento de baja temperatura al circuito principal, en carga.38. Shut-off valve for regulating the return branch of the low temperature storage system to the main circuit, under load.
39. Válvula de cierre-regulación del retorno desde el intercambiador principal 2 a Ia batería de captadores 1 , en el circuito principal.39. Shut-off valve regulating the return from the main exchanger 2 to the collector battery 1, in the main circuit.
40. Válvula de cierre-regulación del ramal de descarga del sistema de almacenamiento de baja temperatura.40. Shut-off valve regulating the discharge branch of the low temperature storage system.
41. Válvula de cierre^regulación del ramal de carga del sistema de almacenamiento de baja temperatura. 42. Entrada del fluido de trabajo del ciclo termodinámico a su bloque de potencia.41. Shut-off valve ^ regulation of the load branch of the low temperature storage system. 42. Input of the working fluid of the thermodynamic cycle to its power block.
43. Salida del fluido de trabajo de su bloque de potencia.43. Output of the working fluid from its power block.
44. Entrada al cuerpo de alta presión del bloque de potencia.44. Entrance to the high pressure body of the power block.
45. Salida del cuerpo de alta presión del bloque de potencia. 46. Entrada al cuerpo de baja presión del bloque de potencia.45. Output of the high pressure body from the power block. 46. Entrance to the low pressure body of the power block.
47. Salida del cuerpo de baja presión del bloque de potencia.47. Output of the low pressure body of the power block.
48. Circuito del fluido de trabajo, recorriendo los sectores 49, 50 y 51.48. Working fluid circuit, covering sectors 49, 50 and 51.
49. Sector, con su batería de captadores, sistemas de almacenamiento térmico e intercambiador principal, de precalentamiento del fluido de trabajo.49. Sector, with its battery of collectors, thermal storage systems and main exchanger, of preheating of the working fluid.
50. Sector, con su batería de captadores, sistemas de almacenamiento térmico e intercambiador principal, de ebullición del fluido de trabajo.50. Sector, with its battery of collectors, thermal storage systems and main exchanger, boiling the working fluid.
51. Sector, con su batería de captadores, sistemas de almacenamiento térmico e intercambiador principal, de sobrecalentamiento del fluido de trabajo.51. Sector, with its battery of collectors, thermal storage systems and main exchanger, of overheating of the working fluid.
52. Sector, con su batería de captadores, sistemas de almacenamiento térmico e intercambiador principal, de recalentamiento del fluido de trabajo. 53. Circuito del fluido de trabajo, recorriendo el sector 52.52. Sector, with its battery of collectors, thermal storage systems and main exchanger, for overheating the working fluid. 53. Working fluid circuit, traveling through sector 52.
54. Bomba de recirculación del fluido de trabajo. Para aquilatar el significado de Ia invención, sobre todo en Io referente al intercambiador principal (2), cabe distinguir dos casos fundamentales: los ciclos con fluido de trabajo condensable, que siguen un ciclo de Rankine o asimilable, y los ciclos con gas no condensable como fluido de trabajo, que corresponden a un ciclo de Brayton (cerrado o abierto, usando típicamente aire en este último caso). En los ciclos tipo Rankine, el intercambiador principal (2) será de contacto indirecto, y su estructura interna se adecuará a Ia fase del ciclo que se aborde en cada sector: en el precalentamiento, sólo se tratará de calentamiento sensible, desde Ia temperatura de condensación, como valor mínimo posible, a Ia de ebullición del fluido de trabajo, " como máximo. Se elegirá posiblemente un intercambiador de tubo y carcasa a contracorriente; en Ia ebullición, el fluido de trabajo estará en cambio de fase y a temperatura constante, y el fluido calorífero estará algunos grados por encima, y se tratará de un generador de vapor, posiblemente con recirculación interior del fluido de trabajo, para mantener un alto coeficiente de película; en el sobrecalentamiento del vapor, el coeficiente de película será mucho menor, y el fluido calorífero tendrá que estar notoriamente más caliente que el vapor.54. Working fluid recirculation pump. In order to assess the meaning of the invention, especially with regard to the main exchanger (2), two fundamental cases can be distinguished: the cycles with condensable working fluid, which follow a Rankine or assimilable cycle, and the cycles with non-condensable gas as a working fluid, which correspond to a Brayton cycle (closed or open, typically using air in the latter case). In the Rankine type cycles, the main exchanger (2) will be of indirect contact, and its internal structure will adapt to the phase of the cycle that is addressed in each sector: in preheating, it will only be sensible heating, from the temperature of condensation, as a minimum possible value, to the boiling of the working fluid, " at most. A tube and shell exchanger will be chosen against the current; in the boiling, the working fluid will be in phase change and at constant temperature, and the heating fluid will be a few degrees above, and it will be a steam generator, possibly with internal recirculation of the working fluid, to maintain a high film coefficient; in steam overheating, the film coefficient will be much lower, and The heating fluid will have to be noticeably hotter than the steam.
En los tres casos se tratará de un intercambiador sin contacto directo entre los fluidos. Algo similar se tendría en un ciclo Brayton si se eligieran fluidos distintos para uno y otro circuito, el solar y el del ciclo termodinámico, pero en este caso sólo se trataría de calentamiento sensible, sin cambio de fase, de modo que podría concentrase toda Ia central en un solo sector, aunque también cabría dividir el campo solar en sectores, cada uno con sus componentes señalados antes, para acomodar el aumento de temperatura de una manera gradual, evitando diferencias térmicas apreciables en un mismo componente. No obstante, en el caso de los ciclos Brayton se puede usar un mismo gas para el fluido calorífero y el fluido de trabajo. En este caso, el intercambiador principalIn all three cases it will be an exchanger without direct contact between the fluids. Something similar would be in a Brayton cycle if different fluids were chosen for either circuit, the solar and the thermodynamic cycle, but in this case it would only be sensible heating, without phase change, so that all the concentration could be concentrated. central in a single sector, although the solar field could also be divided into sectors, each with its components indicated above, to accommodate the temperature increase in a gradual manner, avoiding appreciable thermal differences in the same component. However, in the case of Brayton cycles, the same gas can be used for the heating fluid and the working fluid. In this case, the main exchanger
(2) no sería propiamente un intercambiador de calor, sino un conector de circuitos: El fluido calorífero que entrara por (3), saldría de inmediato por 6 como fluido de trabajo caliente; y el retorno frío de éste, que llegaría por (5), saldría por (4) para volver a Ia batería de captadores solares (1).(2) would not properly be a heat exchanger, but a circuit connector: The heating fluid entering through (3), would immediately leave 6 as a hot working fluid; and the cold return of this one, that would arrive by (5), would leave by (4) to return to the battery of solar collectors (1).
Una identidad similar entre fluidos podría plantearse teóricamente para ciclos Rankine, pero su complejidad tecnológica Io hace desaconsejable. En todo caso, todas las opciones posibles de conexión entre el campo de colectores, donde adquiere energía el fluido calorífero, y el fluido de trabajo termodinámico, se pueden representar según Ia estructura empleada en esta invención y representada en Ia figura 1. La novedad radica en Ia estructuración de los sistemas de almacenamiento térmico, Io cual permite configurar los circuitos del fluido calorífero de forma diferente y específica, Io que comporta modos de funcionamiento específicos de Ia central, en los cuales se mantiene el régimen nominal termodinámico Ia mayor parte del tiempo. En el almacenamiento térmico indirecto o de alta temperatura existe una diferenciación física entre fluidos, incluso en el caso de que fueran de una misma sustancia, es. Su fluido propio no debe mezclarse con el calorífero, pues de éste sólo interesa extraer su temperatura sobre Ia nominal. Más aún, el fluido del almacenamiento puede estar a presión notoriamente inferior a la del calorífero, Io cual puede facilitar enormemente los aspectos constructivos del intercambiador (13) de carga del sistema de almacenamiento de alta temperatura y del depósito (15) del almacenamiento indirecto, o de alta temperatura, que a su vez puede tener un intercambiador de calor indirecto que conecte térmicamente el fluido del almacenamiento con el material termorresistente en sí, así como del intercambiador de descarga (20), que puede llevar a dicho fluido por la carcasa, llevando al calorífero por los tubos (aunque en las figuras no está esquematizado así, pues es el fluido del almacenamiento directo el que va por los tubos).A similar identity among fluids could theoretically be posed to Rankine cycles, but its technological complexity makes it inadvisable. In any case, all the possible connection options between the collector field, where the heating fluid and the thermodynamic working fluid acquire energy, can be represented according to the structure used in this invention and represented in Figure 1. The novelty lies in the structuring of thermal storage systems, which allows the heating fluid circuits to be configured differently and specifically, which involves specific operating modes of the plant, in which the nominal thermodynamic regime is maintained most of the time . In indirect or high temperature thermal storage there is a physical differentiation between fluids, even if they were of the same substance, it is. Its own fluid should not be mixed with the calorific, since it only interests to extract its temperature above the nominal one. Moreover, the storage fluid can be at a pressure significantly lower than that of the calorific, which can greatly facilitate the constructive aspects of the high-temperature storage system load exchanger (13) and the indirect storage tank (15), or high temperature, which in turn can have an indirect heat exchanger that thermally connects the storage fluid with the heat-resistant material itself, as well as the discharge exchanger (20), which can carry said fluid through the housing, leading to the calorific by the tubes (although in the figures it is not schematized thus, since it is the direct storage fluid that goes through the tubes).
También es de reseñar que este almacenamiento indirecto debe ser de baja entropía, de tal manera que Ia temperatura extraída por el fluido del almacenamiento, no se vea reducida por una dispersión del calor en una masa grande de material termorresistente de almacén. Este tipo de almacenamiento puede lograrse de múltiples formas. Por ejemplo, con dos tanques de sales fundidas, uno de base y otro de sales calentadas, que se calentarían al circular por el interior del circuito secundario del intercambiador de carga del sistema de almacenamiento de alta temperatura (14) (que podría estar en Ia carcasa del intercambiador (13) de carga del sistema de almacenamiento de alta temperatura, aunque se haya dibujado de tubos por el interior), las sales calentadas del depósito del almacenamiento indirecto, o de alta temperatura (15) tendrían una temperatura inferior a Ia de salida del campo de colectores en unos diez grados Celsius. El fluido calorífero, en los momentos de mayor irradiación solar, podría proporcionar temperaturas por encima de Ia nominal en unos 30 grados Celsius o más. A su vez habría una pérdida de temperatura en Ia descarga a través del circuito (21) de descarga del sistema indirecto, o de alta temperatura, que es el primario del intercambiador (20), pero en definitiva se consigue que el sistema de almacenamiento de alta temperatura caliente el caudal conjunto, de llegada al intercambiador principal, hasta Ia temperatura nominal.It should also be noted that this indirect storage must be of low entropy, such that the temperature extracted by the storage fluid is not reduced by a dispersion of heat in a large mass of heat-resistant storage material. This type of storage can be achieved in multiple ways. For example, with two tanks of molten salts, one of base and another of heated salts, which would be heated when circulating inside the secondary circuit of the high temperature storage system load exchanger (14) (which could be in Ia housing of the high-temperature storage system load exchanger (13), even if it has been drawn from tubes inside), the heated salts of the indirect storage tank, or high temperature (15) would have a temperature lower than that of Exit the collector field at about ten degrees Celsius. The heating fluid, in the moments of greatest solar irradiation, could provide temperatures above the nominal in about 30 degrees Celsius or more. In turn there would be a loss of temperature in the discharge through the discharge circuit (21) of the indirect system, or high temperature, which is the primary of the exchanger (20), but ultimately it is achieved that the storage system of high hot temperature the whole flow, from arrival to the main exchanger, up to the nominal temperature.
También se podría emplear para el depósito (15) del almacenamiento indirecto, o de alta temperatura, un almacenamiento compartimentado de sólidos refractarios, con compartimentos aislados, de pequeña masa, para evitar pérdida de temperatura por dispersión del calor aportado, aportándose el calor en Ia carga, y extrayéndolo en Ia descarga, merced al fluido del almacenamiento, que ¡nteraccionaría con el intercambiador (13) de carga del sistema de almacenamiento de alta temperatura en Ia carga, y con el intercambiador (20) de descarga del sistema indirecto de almacenamiento térmico, , en Ia descarga, y que podría ser un gas a relativamente baja presión.It could also be used for the storage (15) of indirect storage, or high temperature, a compartmentalized storage of refractory solids, with isolated compartments, of small mass, to avoid loss of temperature by dispersion of the heat provided, providing heat in the loading, and extracting it in the discharge, thanks to the storage fluid, which would interact with the high temperature storage system charge exchanger (13), and with the discharge exchanger (20) of the indirect storage system thermal, in the discharge, and that could be a gas at relatively low pressure.
La figura 2 muestra las partes operativas del sector, en condiciones de irradiación solar en las que no se alcanza el funcionamiento nominal, y no queda energía térmica almacenada en sus sistemas (por ejemplo, al iniciar su régimen diario). El fluido calorífero circula directamente desde Ia batería de captadores solares (1) a su intercambiador principal correspondiente (2), por cuyo circuito secundario circula el fluido de trabajo, para Io cual funciona Ia bomba (34) de recirculación del fluido calorífero en el circuito principal de conexión entre el intercambiador principal 2 y Ia batería de captadores 1 , estando abierta su válvula (39) de cierre-regulación del retorno desde el intercambiador principal (2) a Ia batería de captadores (1), en el circuito principal (véase figura 1). Todos los componentes de carga y descarga térmica de los sistemas de almacenamiento están inactivos, y en particular el intercambiador (13) de carga del sistema de alta, por cuyo circuito secundario (14) no circula fluido, e igualmente inactivo está el intercambiador (20) de descarga del sistema indirecto de almacenamiento térmico. Ambos intercambiadores (13, 20) tienen anulada su capacidad de transferir calor, pasando el fluido de trabajo hacia el intercambiador principal, y las medidas del medidor (23) de caudal másico y de temperatura del fluido a Ia salida del campo de colectores solares (1), del medidor (24) de caudal másico y de temperatura del fluido a Ia salida del intercambiador de carga del sistema de almacenamiento de alta temperatura ,y del medidor (27) de caudal másico y de temperatura del fluido a Ia entrada del intercambiador principal son las mismas, tanto para el caudal másico como para Ia temperatura, pues todas las tuberías y componentes están aislados térmicamente. Las válvulas de los ramales de carga (41 y 38) y descarga (36 y 40) del sistema directo de almacenamiento térmico de baja temperatura están cerradas (véase figura 1). Cuando se supera el nivel de irradiación solar que produce el funcionamiento nominal del ciclo termodinámico de Ia central, el caudal másico y Ia temperatura del fluido calorífero en cada sector están por encima de sus valores nominales correspondientes, activándose el modo de carga térmica de los sistemas de almacenamiento, según se muestra en Ia figura 3. En esta situación, el medidor (23) de caudal másico y de temperatura del fluido a Ia salida del campo de colectores solares (1), marca esos valores de caudal másico y temperatura por encima de Io nominal, y ello pone en marcha Ia circulación por el circuito secundario (14) del intercambiador (13) de alta temperatura, abriendo las válvulas (18) de cierre-regulación del circuito secundario del intercambiador de carga del sistema de almacenamiento de alta temperatura (véase figura 1) y poniendo en marcha Ia bomba (16) de recirculación del fluido del almacenamiento en el circuito de carga del sistema indirecto. El caudal activado de fluido de almacenamiento se ajusta para que adquiera temperatura por encima de Ia nominal, calentándose así el depósito térmico (15) de dicho sistema de alta temperatura. La transferencia se ajusta para que el fluido calorífero salga de dicho intercambiador precisamente a temperatura nominal, Io cual se verifica en el medidor (24) de caudal másico y de temperatura del fluido a Ia salida del intercambiador de carga del sistema de almacenamiento de alta temperatura. Se abren también las válvulas (41 y 38) (véase figura 1) de carga del sistema de almacenamiento de baja temperatura, a través de cuyo ramal pasa el caudal másico de fluido calorífero excedente sobre el valor nominal. El desvío de dicho excedente por dicho ramal se verifica por las medidas del medidor (25) de caudal másico y de temperatura del fluido tras las desviaciones de los ramales de carga y descarga del sistema de almacenamiento de baja temperatura, que tienen que coincidir con los valores nominales. Si no coinciden, se modifican los estados de las válvulas y bombas involucradas. Por ejemplo, si el caudal másico medido en (25) es demasiado alto, se han de abrir más las válvulas de cierre-regulación del ramal de carga del sistema de almacenamiento de baja temperatura (41) y de cierre-regulación del ramal de retorno del sistema de almacenamiento de baja temperatura al circuito principal, en carga (38) (véase figura 1), y eventualmente dar más potencia a Ia bomba (37) de recirculación del fluido calorífero en el retorno de conexión entre el almacenamiento directo y el circuito principal, en carga del almacenamiento. Mediante estas acciones y verificaciones, se logra que llegue por el circuito principal, al intercambiador principal, exactamente el caudal nominal de fluido calorífero, con Ia temperatura nominal, manteniéndose así el funcionamiento nominal del ciclo termodinámico de Ia central. Al mismo tiempo va aumentando Ia energía térmica almacenada en los sistemas indirecto (15) y directo (22), cuyas temperaturas se controlan por los medidores de temperatura del depósito de material termorresistente del almacenamiento de alta temperatura (32) y de temperatura del depósito de material termorresistente del almacenamiento de baja temperatura (33) respectivamente, que miden sobre Ia parte o masa del depósito de material termorresistente que se ha energizado ya en ese momento.Figure 2 shows the operative parts of the sector, in conditions of solar irradiation in which the nominal operation is not reached, and there is no thermal energy stored in its systems (for example, at the beginning of its daily regime). The heating fluid circulates directly from the solar collector battery (1) to its corresponding main exchanger (2), through whose secondary circuit the working fluid circulates, for which the pump (34) of recirculation of the heating fluid in the circuit operates. main connection between the main exchanger 2 and the collector battery 1, with its valve (39) closing-regulating the return from the main exchanger (2) to the collector battery (1) being open, in the main circuit (see Figure 1). All the components of loading and thermal unloading of the storage systems are inactive, and in particular the loading system exchanger (13), through which secondary circuit (14) does not circulate fluid, and the exchanger (20) is also inactive. ) discharge of the indirect thermal storage system. Both exchangers (13, 20) have canceled their ability to transfer heat, passing the working fluid to the main exchanger, and the measurements of the mass flow meter and fluid temperature at the exit of the field of solar collectors ( 1), of the mass flow meter and fluid temperature meter at the outlet of the high temperature storage system load exchanger, and of the mass flow meter and fluid temperature meter (27) at the inlet of the exchanger main are the same, both for the mass flow and for the temperature, since all the pipes and components are thermally insulated. The valves of the loading (41 and 38) and discharge (36 and 40) branches of the direct low temperature thermal storage system are closed (see figure 1). When the level of solar irradiation that produces the nominal operation of the thermodynamic cycle of the plant is exceeded, the mass flow rate and the temperature of the heating fluid in each sector are above their corresponding nominal values, activating the thermal load mode of the systems storage, as shown in Figure 3. In this situation, the mass flow meter and fluid temperature meter at the exit of the solar collector field (1), marks those values of mass flow and temperature above of nominal, and this starts up the circulation through the secondary circuit (14) of the high temperature exchanger (13), opening the closing valves (18) of the secondary circuit of the load exchanger of the high storage system temperature (see figure 1) and starting the recirculation pump (16) of the storage fluid in the charging circuit of the indirect system. The activated flow of storage fluid is adjusted so that it acquires a temperature above the nominal one, thus heating the thermal reservoir (15) of said high temperature system. The transfer is adjusted so that the heating fluid leaves said exchanger precisely at nominal temperature, which is verified in the mass flow meter and fluid temperature at the outlet of the load exchanger of the high temperature storage system . The valves (41 and 38) (see figure 1) of the low temperature storage system are also opened, through which the mass flow of excess heating fluid over the nominal value passes. The diversion of said surplus through said branch is verified by the measurements of the mass flow meter and fluid temperature (25) after the deviations of the loading and unloading branches of the low temperature storage system, which have to coincide with the nominal values. If they do not match, the states of the valves and pumps involved are modified. For example, if the mass flow rate measured in (25) is too high, the closing-regulation valves of the load branch of the low temperature storage system (41) and the closing-regulation of the return branch must be opened further from the low temperature storage system to the main circuit, on load (38) (see figure 1), and eventually give more power to the recirculation pump (37) of the heating fluid in the connection return between direct storage and main circuit, in storage load. By means of these actions and verifications, it is possible that the nominal heat flow of the heating fluid arrives through the main circuit, with the nominal temperature, thus maintaining the nominal operation of the thermodynamic cycle of the plant. At the same time, the thermal energy stored in the indirect (15) and direct (22) systems is increased, whose temperatures are controlled by the temperature meters of the high-temperature storage material of the high-temperature storage (32) and the temperature of the storage tank. heat-resistant material of the low temperature storage (33) respectively, which measure on the part or mass of the tank of heat-resistant material that has already been energized at that time.
Al declinar Ia actividad solar diaria, o cuando en general se está por debajo del nivel de irradiación solar que produce el funcionamiento nominal del ciclo termodinámico de Ia central, los valores de caudal másico y temperatura del fluido calorífero a Ia salida de Ia batería de captadores solares están por debajo de los nominales correspondientes, Io cual se detecta en el medidor (23) de caudal másico y de temperatura del fluido a Ia salida del campo de colectores solares (1). Entonces se activan los sistemas de descarga térmica de ambos almacenamientos, según se visualiza en Ia figura 4. Desde el sistema directo (22), o de baja temperatura, se aporta el caudal másico de fluido calorífero que falta para completar hasta el valor nominal el caudal másico aportado por el campo de colectores, Io cual se verifica por el medidor (25) de caudal másico y de temperatura del fluido tras las desviaciones de los ramales de carga y descarga del sistema de almacenamiento de baja temperatura, dando el medidor (26) de caudal másico y de temperatura del fluido en Ia inyección de descarga del sistema de almacenamiento térmico directo, Ia medida del caudal másico aportado por el almacenamiento, que ha de ser Io complementario de Io medido por el medidor (23) de caudal másico y de temperatura del fluido a Ia salida del campo de colectores solares (1) (véase figura 1). En caso de necesidad de aumento del caudal complementario, se abren más Ia válvula (36) de cierre- regulación del ramal de retorno al sistema de almacenamiento de baja temperatura (22) y Ia válvula (40) de cierre-regulación del ramal de descarga del sistema de almacenamiento de baja temperatura , o eventualmente se da más potencia a Ia bomba (35) de recirculación del fluido calorífero en el retorno de conexión entre el intercambiador principal (2) y el almacenamiento directo (22). El medidor (25) de caudal másico y de temperatura del fluido tras las desviaciones de los ramales de carga y descarga del sistema de almacenamiento de baja temperatura, señala que el caudal másico es el nominal, pero Ia temperatura no llega a nominal, por Io que ese caudal conjunto se calienta en el intercambiador de descarga (20) aprovechando el calor del almacenamiento de alta temperatura (15), cuyo fluido se pone en circulación al abrir las válvulas (19) de cierre-regulación del circuito primario del intercambiador de descarga del sistema de almacenamiento de alta temperatura (véase figura 1) y poner en marcha Ia bomba (17) de recirculación del fluido del almacenamiento en el circuito de descarga del sistema indirecto, o de alta temperatura, con Ia que se regula el movimiento del fluido de ese almacenamiento, de tal forma que en el medidor (27) de caudal másico y de temperatura del fluido a Ia entrada del intercambiador principal, se verifique que Ia temperatura es Ia nominal.When the daily solar activity declines, or when in general it is below the level of solar irradiation that produces the nominal operation of the thermodynamic cycle of the plant, the values of mass flow and temperature of the heating fluid at the outlet of the collector battery solar are below the corresponding nominal, which is detected in the meter (23) of mass flow and fluid temperature at the exit of the field of solar collectors (1). Then the thermal discharge systems of both stores are activated, as shown in Figure 4. From the direct system (22), or of low temperature, the mass flow of heating fluid that is missing to complete up to the nominal value is provided. mass flow rate provided by the collector field, which is verified by the mass flow meter and fluid temperature meter (25) after deviations of the loading and unloading branches of the low temperature storage system, giving the meter (26 ) of mass flow and fluid temperature in the injection injection of the direct thermal storage system, the measurement of the mass flow contributed by the storage, which must be complementary to that measured by the mass flow meter (23) and of temperature of the fluid at the exit of the field of solar collectors (1) (see figure 1). In case of need to increase the complementary flow, the closing valve (36) of the return branch to the low temperature storage system (22) and the closing valve (40) of the discharge branch are opened further of the low temperature storage system, or eventually more power is given to the heat recirculation pump (35) in the return connection between the main exchanger (2) and the direct storage (22). The meter (25) of mass flow and fluid temperature after deviations of the loading and unloading branches of the low temperature storage system, indicates that the mass flow is nominal, but the temperature does not reach nominal, for Io that this combined flow is heated in the discharge exchanger (20) taking advantage of the heat of the high temperature storage (15), whose fluid is put into circulation when opening the shut-off valves (19) of the primary circuit of the discharge exchanger of the high temperature storage system (see figure 1) and start the recirculation pump (17) of the storage fluid in the discharge circuit of the indirect system, or high temperature, with which the movement of the fluid is regulated of that storage, so that in the meter (27) of mass flow and fluid temperature at the inlet of the main exchanger, it is verified that the temperature is the nomination to the.
Cuando Ia irradiación solar se hace nula, son nulos el calor y el caudal aportados por Ia batería de captadores solares, y el funcionamiento del intercambiador principal, y por ende del ciclo termodinámico, depende exclusivamente de los sistemas de almacenamiento, Io cual se plasma en Ia figura 5.When the solar irradiation becomes null, the heat and the flow contributed by the battery of solar collectors are null, and the operation of the main exchanger, and therefore of the thermodynamic cycle, depends exclusively on the storage systems, which is reflected in Figure 5.
Como elemento indispensable para Ia gestión de las diversas corrientes del fluido calorífero en los diversos modos de funcionamiento, se cuenta con un depósito (7) que contiene fluido calorífero, y al cual se puede evacuar parte del contenido másico que hay en el circuito, abriendo Ia válvula (9) de cierre- regulación del ramal de trasiego (8) del fluido calorífero al depósito, desde el circuito, o al revés, inyectar en el circuito más fluido, a más presión, para Io que se cuenta con Ia bomba (12) de trasiego del fluido calorífero desde el depósito al circuito, abriéndose a tal efecto Ia válvula (11) de cierre-regulación del ramal de trasiego del fluido calorífero (10) desde el depósito al circuito.As an indispensable element for the management of the various currents of the heating fluid in the different modes of operation, there is a tank (7) that contains heating fluid, and to which part of the mass content in the circuit can be evacuated, opening The shut-off valve (9) regulating the transfer branch (8) of the heating fluid to the tank, from the circuit, or vice versa, injecting in the more fluid circuit, at more pressure, for which the pump is provided ( 12) of transfer of the heating fluid from the tank to the circuit, the valve (11) opening-regulating the transfer branch of the heating fluid (10) from the tank to the circuit being opened for this purpose.
Sectores como los descritos, integrados por una batería de captadores, los sistemas de almacenamiento, el intercambiador principal y los elementos auxiliares de circulación, instrumentación y control de flujo, se agrupan, compartiendo el fluido de trabajo, para dar lugar a una central termo-solar con gestión energética encaminada a su optimación exergética, de Io cual se presenta un esquema en Ia figura 6. En Ia figura se han representado cuatro sectores, que conceptualmente, por su posición relativa, pueden calificarse de sector de precalentamiento (49); sector de generación de vapor (50); sector de sobrecalentamiento (51) y sector de recalentamiento (52). En el sector de precalentamiento (49), el fluido de trabajo está en fase líquida, y pasa por el intercambiador principal (2) de dicho sector, que tendrá una batería de captadores solares adecuada a ese rango de temperaturas, señalándose que en ese intercambiador, el coeficiente de película del fluido de trabajo será moderado, mucho menor que el que tendrá el fluido en el intercambiador principal (2) del sector (50) con su batería de captadores, sistemas de almacenamiento térmico e intercambiador principal, de ebullición del fluido de trabajo, pues en éste habrá ebullición nucleada, y su coeficiente de película tendrá valores muy altos; que también serán más altos que en los sectores donde el fluido de trabajo circula como vapor seco, sector (51) con su batería de captadores, sistemas de almacenamiento térmico e intercambiador principal, de sobrecalentamiento del fluido de trabajo (51) o secándose de nuevo en el sector de recalentamiento del fluido de trabajo (52). Estas diferencias en los coeficientes de transmisión de calor aconsejan sectores con fluidos caloríferos distintos, o el mismo fluido, pero con diferentes valores de temperatura, presión y caudal. La identificación de los sectores necesarios se realiza aplicando el criterio de que las especificidades de calentamiento de los sectores comporten valores del factor de concentración solar o del coeficiente global de transmisión de calor, que difieran entre sectores más de un 25%. Una vez descrita de forma clara Ia invención, se hace constar que las realizaciones particulares anteriormente descritas son susceptibles de modificaciones de detalle siempre que no alteren el principio fundamental y Ia esencia de Ia invención. Sectors such as those described, integrated by a battery of collectors, storage systems, the main exchanger and the auxiliary elements of circulation, instrumentation and flow control, are grouped, sharing the working fluid, to give rise to a thermal power plant. solar with energy management aimed at its exergy optimization, of which a scheme is presented in figure 6. In the figure four sectors have been represented, which conceptually, by their relative position, can be described as preheating sector (49); steam generation sector (50); overheating sector (51) and overheating sector (52). In the sector of preheating (49), the working fluid is in liquid phase, and passes through the main exchanger (2) of said sector, which will have a battery of solar collectors suitable to that temperature range, indicating that in that exchanger, the coefficient of film of the working fluid will be moderate, much smaller than the one that will have the fluid in the main exchanger (2) of the sector (50) with its battery of sensors, thermal storage systems and main exchanger, of boiling of the working fluid, because in this one there will be nucleated boiling, and its film coefficient will have very high values; which will also be higher than in the sectors where the working fluid circulates as dry steam, sector (51) with its battery of collectors, thermal storage systems and main exchanger, of overheating of the working fluid (51) or drying again in the sector of overheating of the working fluid (52). These differences in the heat transmission coefficients advise sectors with different heating fluids, or the same fluid, but with different values of temperature, pressure and flow. The identification of the necessary sectors is carried out by applying the criterion that the heating specificities of the sectors involve values of the solar concentration factor or the global heat transmission coefficient, which differ between sectors by more than 25%. Once the invention is clearly described, it is stated that the particular embodiments described above are subject to modifications in detail provided that they do not alter the fundamental principle and the essence of the invention.

Claims

REIVINDICACIONES
1 - Central helio-térmica con gestión exergética del calor, basada en una configuración de central solar térmica con captadores solares de concentración de Ia radiación que sirven para calentar un fluido calorífero, que a su vez alimenta energéticamente a un fluido de trabajo de un ciclo termodinámico, caracterizada por que se estructura en un conjunto de sectores por los que consecutivamente circula el fluido de trabajo, identificándose los sectores necesarios por aplicación del criterio de que las especificidades de calentamiento en los sectores comporten valores del factor de concentración solar, o del coeficiente global de transmisión de calor entre Ia superficie de absorción y el fluido calorífero, que difieran entre sectores consecutivos más de un 25%; pudiendo eventualmente haber un único sector, por identificarse sólo una función de calentamiento del fluido de trabajo, que en todo caso es el mismo en todos los sectores que potencialmente tenga Ia central, y están conectados entre sí a través de un único circuito de fluido de trabajo; y teniendo el fluido calorífero, una corriente o circuito específico para cada sector, Io cual incluye sus propios sistemas de almacenamiento térmico, indirecto o de alta temperatura y directo o de relativamente baja temperatura, entendiendo por relativamente baja temperatura que está por debajo de Ia temperatura nominal del fluido calorífero de ese sector, y una pluralidad de bombas o compresores, válvulas y detectores de instrumentación que constituyen también el circuito termo-fluido de cada sector de Ia central; que como circuito cuenta también con una pluralidad de intercambiadores de calor (13, 20) que conectan térmicamente con el sistema de almacenamiento térmico indirecto en su carga y en su descarga, y con el intercambiador de calor principal (2) entre el fluido calorífero y el fluido de trabajo que conecta térmicamente con el circuito del fluido de trabajo termodinámico.1 - Helio-thermal power plant with exergy heat management, based on a configuration of solar thermal power plant with solar collectors of concentration of the radiation that serve to heat a heating fluid, which in turn feeds energy to a working fluid of a cycle thermodynamic, characterized in that it is structured in a set of sectors through which the working fluid flows consecutively, identifying the necessary sectors by applying the criterion that the specificities of heating in the sectors involve values of the solar concentration factor, or the coefficient global heat transfer between the absorption surface and the heating fluid, which differ between consecutive sectors by more than 25%; There may eventually be a single sector, because only one function of heating the working fluid is identified, which in any case is the same in all sectors that potentially have the power plant, and are connected to each other through a single fluid circuit of job; and having the heating fluid, a specific current or circuit for each sector, which includes its own thermal storage systems, indirect or high temperature and direct or relatively low temperature, meaning relatively low temperature that is below the temperature nominal of the heating fluid of that sector, and a plurality of pumps or compressors, valves and instrumentation detectors that also constitute the thermo-fluid circuit of each sector of the plant; which as a circuit also has a plurality of heat exchangers (13, 20) that thermally connect with the indirect thermal storage system in its load and in its discharge, and with the main heat exchanger (2) between the heating fluid and the working fluid that thermally connects to the thermodynamic working fluid circuit.
2 - Central helio-térmica con gestión exergética del calor, según reivindicación primera, caracterizada por que cada sector de Ia central consiste en un gran circuito termo-fluido que contiene: - una batería de captadores de radiación solar (1), que comprende una parte de concentración óptica y unos tubos absorbedores por cuyo interior circula y se calienta el fluido calorífero; un intercambiador principal (2), que puede ser de contacto directo o indirecto, según el tipo de ciclo termodinámico empleado, y que transfiere el calor del fluido calorífero al fluido de trabajo termodinámico, efectuando en esa transmisión Ia función específica de ese sector del campo, que puede ser de mero calentamiento sensible, con el consiguiente aumento de temperatura del fluido de trabajo, o de ebullición de éste cuando Ia función es Ia de generación de vapor; aunque en el caso de contacto directo en el .intercambiador, el mismo fluido calorífero pasa a ser fluido de trabajo, saliendo como tal de este componente por el conducto (6), y volviendo a él como fluido de trabajo retornado por el conducto (5), pasando a ser de nuevo fluido calorífero al volver a salir del intercambiador por el conducto (4) que comunica con el circuito que va a Ia batería de captadores solares 1 ; un depósito (7) del fluido calorífero que aporta fluido al circuito del sector, o Io extrae, en función de las condiciones de trabajo del sector; una pluralidad de circuladores, seleccionados entre bombas o compresores, (34), que propician el movimiento del fluido calorífero a Io largo del circuito del sector, y las válvulas de corte y de regulación, (39), que controlan ese movimiento; - un sistema de almacenamiento indirecto, o de alta temperatura, entendiendo por esta denominación que está por encima de Ia temperatura nominal del fluido calorífero de ese sector, es decir, Ia temperatura para alimentar nominalmente al intercambiador principal (2) de conexión térmica con el fluido de trabajo, especificándose que este sistema tiene su propio fluido interior, que no se mezcla con el fluido calorífero; un sistema de almacenamiento térmico general, o directo, de relativamente baja temperatura, entendiendo por esta denominación que está por debajo de Ia temperatura nominal del fluido calorífero de ese sector, coincidiendo en este caso el fluido primario del almacenamiento con el propio fluido calorífero.2 - Helio-thermal power plant with exergy management of heat, according to claim one, characterized in that each sector of the plant consists of a large thermo-fluid circuit containing: - a battery of solar radiation collectors (1), comprising a part of optical concentration and absorber tubes through which the heating fluid circulates and heats; a main exchanger (2), which can be of direct or indirect contact, depending on the type of thermodynamic cycle used, and which transfers heat from the heating fluid to the fluid of thermodynamic work, performing in that transmission the specific function of that sector of the field, which can be of mere sensible heating, with the consequent increase in temperature of the working fluid, or of boiling of this when the function is the steam generation ; although in the case of direct contact in the exchanger, the same heating fluid becomes working fluid, leaving this component as such through the conduit (6), and returning to it as working fluid returned by the conduit (5 ), again becoming heat fluid when the exchanger leaves the duct again (4) that communicates with the circuit that goes to the solar collector battery 1; a reservoir (7) of the heating fluid that provides fluid to the sector circuit, or extracts it, depending on the working conditions of the sector; a plurality of circulators, selected from pumps or compressors, (34), which promote the movement of the heating fluid along the sector circuit, and the shut-off and regulating valves, (39), which control that movement; - an indirect or high temperature storage system, meaning that this designation is above the nominal temperature of the heating fluid of that sector, that is, the temperature to nominally feed the main heat exchanger (2) of thermal connection with the working fluid, specifying that this system has its own internal fluid, which does not mix with the heating fluid; a general, or direct, thermal storage system of relatively low temperature, this denomination being understood to be below the nominal temperature of the heating fluid of that sector, in this case the primary storage fluid coinciding with the heating fluid itself.
3 - Central helio-térmica con gestión exergética del calor, según reivindicaciones primera y segunda, caracterizada por que el sistema de almacenamiento de alta temperatura comprende: un intercambiador de calor (13) de conexión térmica del fluido calorífero emergente de Ia batería de captadores solares (1) con el almacenamiento de alta temperatura (15), siendo este intercambiador de contacto térmico indirecto del fluido calorífero con el fluido del almacenamiento, y no habiendo por tanto mezcla alguna de los dos fluidos; un depósito, seleccionado entre simple o múltiple,3 - Helio-thermal power plant with exergy heat management, according to first and second claims, characterized in that the high temperature storage system comprises: a heat exchanger (13) for thermal connection of the emergent heating fluid of the solar collector battery (1) with the high temperature storage (15), this heat exchanger being an indirect thermal contact of the heating fluid with the storage fluid, and therefore no mixing of the two fluids ; a deposit, selected from single or multiple,
(15), de material termorresistente que acoge el calor aportado por el intercambiador (13); y que como material termorresistente puede usar al propio fluido del almacenamiento que circula por el circuito (14); y que en el caso de contacto térmico interno indirecto, tiene su propio intercambiador de calor indirecto que conecta térmicamente el fluido del almacenamiento con el material termorresistente en sí; una pluralidad de circuladores, seleccionados entre bombas o compresores, (16), que propician el movimiento del fluido del almacenamiento a Io largo del circuito de carga térmica del depósito mencionado de alta temperatura, y las válvulas de corte y de regulación, (18), que controlan el movimiento; un intercambiador de calor (20) de descarga térmica del almacenamiento de alta temperatura (15), con contacto térmico indirecto del fluido del almacenamiento con el fluido calorífero, que emerge calentado de éste intercambiador, para entrar en el intercambiador principal (2), donde está conectado térmicamente con el fluido de trabajo; - una pluralidad de circuladores, seleccionados entre bombas o compresores, (17), que propician el movimiento del fluido del almacenamiento indirecto a Io largo del circuito de descarga del almacenamiento de alta temperatura, y las válvulas de corte y de regulación, (19), que controlan el movimiento de su fluido para conectarse térmicamente con el fluido calorífero a través del intercambiador de descarga, (20).(15), of heat-resistant material that receives the heat provided by the exchanger (13); and that as a heat-resistant material it can use the storage fluid itself that circulates through the circuit (14); and that in the case of indirect internal thermal contact, it has its own indirect heat exchanger that thermally connects the storage fluid with the heat-resistant material itself; a plurality of circulators, selected from pumps or compressors, (16), which promote the movement of the storage fluid along the thermal load circuit of the mentioned high temperature tank, and the shut-off and regulating valves, (18) , which control the movement; a heat exchanger (20) for thermal discharge of high temperature storage (15), with indirect thermal contact of the storage fluid with the heating fluid, which emerges heated from this exchanger, to enter the main exchanger (2), where It is thermally connected to the working fluid; - a plurality of circulators, selected from pumps or compressors, (17), which promote the movement of the indirect storage fluid along the discharge circuit of the high temperature storage, and the shut-off and regulating valves, (19) , which control the movement of its fluid to thermally connect with the heating fluid through the discharge exchanger, (20).
4 - Central helio-térmica con gestión exergética del calor, según cualquiera de las reivindicaciones anteriores, caracterizada por que el sistema de almacenamiento térmico general o directo, de relativamente baja temperatura comprende: un depósito (22) de material termorresistente que acoge el calor aportado directamente por el fluido calorífero, bien por calentamiento directo; bien por disponer de un intercambiador de calor indirecto que conecte térmicamente el fluido calorífero con el material termorresistente en sí; - un circuito de carga térmica, que está controlado por dos válvulas (38 y 41), y que extrae fluido calorífero del circuito principal de éste, que es el que conecta Ia batería de captadores solares con el intercambiador principal, para que ceda su calor en el almacenamiento directo, devolviendo el caudal del fluido calorífero aguas abajo del intercambiador principal,; un circuito de descarga térmica, inverso al anterior, y que está controlado por dos válvulas (36 y 40), que toma fluido calorífero tras emerger del intercambiador principal, y es devuelto, tras calentarse a su paso por el almacenamiento, aguas arriba del intercambiador de descarga térmica del sistema de almacenamiento indirecto; una pluralidad de circuladores, seleccionados entre bombas o compresores, (35, 37) que propician el movimiento del fluido calorífero a lo largo de los circuitos de carga y descarga térmica del almacenamiento de baja temperatura, y las válvulas de corte y de regulación, (36, 38, 40 y 41), de los circuitos de carga y descarga térmica, que controlan el movimiento de este fluido para conectarse directamente con el circuito del fluido calorífero.4 - Helio-thermal power plant with exergy heat management, according to any of the preceding claims, characterized in that the general or direct thermal storage system of relatively low temperature comprises: a reservoir (22) of heat-resistant material that it receives the heat provided directly by the heating fluid, either by direct heating; either by having an indirect heat exchanger that thermally connects the heating fluid with the heat-resistant material itself; - a thermal load circuit, which is controlled by two valves (38 and 41), and which extracts heat fluid from the main circuit of the latter, which is the one that connects the solar collector battery to the main exchanger, so that its heat yields in direct storage, returning the flow of the heating fluid downstream of the main exchanger; a thermal discharge circuit, inverse to the previous one, and which is controlled by two valves (36 and 40), which takes heating fluid after emerging from the main exchanger, and is returned, after heating as it passes through storage, upstream of the exchanger thermal discharge of the indirect storage system; a plurality of circulators, selected from pumps or compressors, (35, 37) that promote the movement of the heating fluid along the thermal loading and unloading circuits of the low temperature storage, and the cutting and regulating valves, ( 36, 38, 40 and 41), of the thermal loading and unloading circuits, which control the movement of this fluid to connect directly with the heating fluid circuit.
5 - Central helio-térmica con gestión exergética del calor, según cualquiera de las reivindicaciones 1-4, caracterizada por que la central, y cada uno de sus sectores, se configura con el siguiente circuito de funcionamiento, que se determina por Ia apertura de válvulas y por Ia activación de las bombas o circuladores realizadas teniendo en cuenta que Ia posición o estado, por defecto, de las válvulas será Ia de cierre, y en las bombas Ia de inactivación de tal manera que en condiciones de captación de Ia irradiación solar con las que no se alcanza el funcionamiento nominal, y no queda energía térmica almacenada en sus sistemas de almacenamiento de alta temperatura y de almacenamiento térmico de baja temperatura, en cada sector de Ia central el fluido calorífero circula directamente desde Ia batería de captadores solares (1) a su intercambiador principal (2) correspondiente, por cuyo circuito secundario circula el fluido de trabajo, estando inactivos todos los componentes de carga y descarga térmica de los sistemas de almacenamiento, y en particular el intercambiador (13) de carga del sistema de alta temperatura, por cuyo circuito secundario (14) no circula fluido, estando el funcionamiento del intercambiador anulado a tales efectos, estando Ia válvula (18) de cierre-regulación del circuito secundario del intercambiador de carga del sistema de almacenamiento de alta temperatura y Ia válvula (19) de cierre-regulación del circuito primario del intercambiador de descarga del sistema de almacenamiento de alta temperatura, cerradas, y las bombas (16) de recirculación del fluido del almacenamiento en el circuito de carga del sistema indirecto y (17) de recirculación del fluido del almacenamiento en el circuito de descarga del sistema indirecto, o de alta temperatura, inactivas; y estando cerradas las válvulas (41 y 38, y 36 y 40), de los ramales de carga y descarga del sistema directo de almacenamiento térmico de baja temperatura , estando además inactivas Ia bomba (35) de recirculación del fluido calorífero en el retorno de conexión entre el intercambiador principal (2) y el sistema de almacenamiento directo, y Ia bomba (37) de recirculación del fluido calorífero en el retorno de conexión entre el almacenamiento directo y el circuito principal, en carga del almacenamiento. 6 - Central helio-térmica con gestión exergética del calor, según cualquiera de las reivindicaciones 1-4, caracterizada por que Ia central, y cada uno de sus sectores, se configura con el siguiente circuito de funcionamiento, que se determina por Ia apertura de válvulas y por Ia activación de las bombas o circuladores realizadas teniendo en cuenta que Ia posición o estado, por defecto, de las válvulas será Ia de cierre, y en las bombas Ia de inactivación de tal manera que en condiciones en las que se ha superado el nivel de captación solar que produce el funcionamiento nominal del ciclo termodinámico de Ia central, el caudal másico y Ia temperatura del fluido calorífero a Ia salida de Ia batería de captadores solares (1) de cada sector van por encima de sus valores nominales correspondientes, y se activa el modo de carga térmica de los sistemas de almacenamiento, estableciéndose Ia circulación por el circuito secundario (14) del intercambiador (13) de alta temperatura, por Io que a Ia salida del mismo, el fluido del almacenamiento adquiere temperatura por encima de Ia nominal, calentándose así el depósito térmico (15) de dicho sistema de alta temperatura, saliendo por el circuito primario de dicho intercambiador el fluido calorífero a temperatura nominal, estando abiertas las válvulas (18) de cierre- regulación del circuito secundario del ¡ntercambiador de carga del sistema de almacenamiento de alta temperatura y activada Ia bomba (16) de recirculación del fluido del almacenamiento en el circuito de carga del sistema indirecto; y abriéndose las válvulas (41 , 38) del ramal de carga del sistema de almacenamiento de baja temperatura y del ramal de retorno del sistema de almacenamiento de baja temperatura al circuito principal, en carga, a través de cuyo ramal, en el que está activada Ia bomba (37) de recirculación del fluido calorífero en el retorno de conexión entre el almacenamiento directo y el circuito principal, en carga del almacenamiento, pasa el caudal de fluido calorífero excedente sobre el valor nominal, para volver a Ia batería de captadores (1); llegando por el circuito principal, al intercambiador principal (2), exactamente el caudal nominal de fluido calorífero, con Ia temperatura nominal, Io cual se verifica por el medidor de caudal másico y de temperatura del fluido del sistema de almacenamiento de baja temperatura (25) y el medidor de caudal másico y de temperatura del fluido a Ia entrada del intercambiador principal (27), manteniéndose así el funcionamiento nominal del ciclo termodinámico de Ia central.5 - Helio-thermal power plant with exergy heat management, according to any of claims 1-4, characterized in that the power plant, and each of its sectors, is configured with the following operating circuit, which is determined by the opening of valves and by the activation of the pumps or circulators carried out taking into account that the position or state, by default, of the valves will be the closing one, and in the pumps Ia of inactivation in such a way that in conditions of capture of the solar irradiation with which the nominal operation is not reached, and there is no thermal energy stored in its high temperature storage and low temperature thermal storage systems, in each sector of the plant the heating fluid circulates directly from the solar collector battery ( 1) to its corresponding main exchanger (2), through whose secondary circuit the working fluid circulates, all the thermal loading and unloading components of the storage systems being inactive, and in particular the high temperature system charging exchanger (13), through which secondary circuit (14) does not circulate fluid, the operation of the exchanger being canceled for such purposes, the shut-off valve (18) being the secondary circuit of the load exchanger of the high temperature storage system and the valve (19) ) Close-regulation of the primary circuit of the high temperature storage system discharge exchanger, closed, and the pumps (16) for recirculation of the storage fluid in the charging circuit of the indirect system and (17) for the recirculation of the fluid of storage in the discharge circuit of the indirect, or high-temperature, inactive system; and the valves (41 and 38, and 36 and 40), of the loading and unloading branches of the direct low temperature thermal storage system being closed, the heat recirculation pump (35) being inactive in the return of connection between the main exchanger (2) and the direct storage system, and the heating fluid recirculation pump (37) in the return connection between the direct storage and the main circuit, in charge of the storage. 6 - Helio-thermal power plant with exergy heat management, according to any of claims 1-4, characterized in that the power plant, and each of its sectors, is configured with the following operating circuit, which is determined by the opening of valves and by the activation of the pumps or circulators carried out taking into account that the position or state, by default, of the valves will be the closing one, and in the pumps Ia of inactivation in such a way that in conditions in which it has been exceeded the level of solar collection that produces the nominal operation of the thermodynamic cycle of the plant, the mass flow and the temperature of the heating fluid at the exit of the battery of solar collectors (1) of each sector are above their corresponding nominal values, and the thermal load mode of the storage systems is activated, the circulation being established through the secondary circuit (14) of the high temperature exchanger (13) , so that at the exit of the same, the storage fluid acquires a temperature above the nominal one, thus heating the thermal tank (15) of said high temperature system, leaving the heat exchanger fluid at the primary circuit of said exchanger nominal, with the shut-off valves (18) open- regulation of the secondary circuit of the high temperature storage system load exchanger and activated the recirculation pump (16) of the storage fluid in the indirect system load circuit; and the valves (41, 38) of the loading branch of the low temperature storage system and the return branch of the low temperature storage system to the main circuit, being loaded, through whose branch, in which it is activated, are opened Ia pump (37) of recirculation of the heating fluid in the return connection between the direct storage and the main circuit, in charge of the storage, passes the flow of excess heating fluid over the nominal value, to return to the collector battery (1 ); arriving through the main circuit, to the main exchanger (2), exactly the nominal flow rate of the heating fluid, with the nominal temperature, which is verified by the mass flow rate and fluid temperature meter of the low temperature storage system (25 ) and the mass flow and fluid temperature meter at the inlet of the main exchanger (27), thus maintaining the nominal operation of the thermodynamic cycle of the plant.
7 -Central helio-térmica con gestión exergética del calor, según cualquiera de las reivindicaciones 1-4, caracterizada por que Ia central, y cada uno de sus sectores, se configura con el siguiente circuito de funcionamiento, que se determina por Ia apertura de válvulas y por Ia activación de las bombas o circuladores realizadas teniendo en cuenta que Ia posición o estado, por defecto, de las válvulas será Ia de cierre, y en las bombas Ia de inactivación de tal manera que estando llenos total o parcialmente los depósitos térmicos de alta temperatura (15) y de baja temperatura (22) de los sistemas de almacenamiento de alta y baja temperatura respectivamente, y estando en condiciones de captación de Ia irradiación solar que no llega a producir el funcionamiento nominal del ciclo termodinámico de Ia central, los valores de caudal másico y temperatura del fluido calorífero a Ia salida de Ia batería de captadores solares (1) son insuficientes, al estar por debajo de los valores nominales correspondientes, y en tal caso se activan los sistemas de descarga térmica de ambos depósitos (15 y 22), aportándose por el sistema directo, o de baja temperatura, el caudal másico de fluido calorífero que falta para completar hasta el valor nominal el caudal másico aportado por Ia batería de captadores solares (1), para Io cual se activa Ia bomba (35) y se abren las válvulas (36) y (40); y se calienta el caudal conjunto de fluido calorífero, tras esa complementación, hasta el valor nominal de temperatura, por Ia acción del intercambiador (20) de descarga térmica del almacenamiento indirecto o de alta temperatura, para Io cual se abren las válvulas (19) y se activa Ia bomba (17); y por Io cual, Ia mezcla o caudal conjunto de los caudales másicos, aportados desde Ia batería de captadores solares (1) y desde el almacenamiento directo, al intercambiador principal (2), tiene no sólo el caudal másico nominal, sino Ia temperatura nominal, lo que se verifica por el medidor (27). 7 -Helio-thermal center with exergy heat management, according to any of claims 1-4, characterized in that the plant, and each of its sectors, is configured with the following operating circuit, which is determined by the opening of valves and by the activation of the pumps or circulators carried out taking into account that the position or state, by default, of the valves will be the closing one, and in the pumps Ia of inactivation in such a way that the thermal deposits are totally or partially filled high temperature (15) and low temperature (22) of high and low temperature storage systems respectively, and being able to capture solar irradiation that does not produce the nominal operation of the thermodynamic cycle of the plant, the values of mass flow and temperature of the heating fluid at the exit of the solar collector battery (1) are insufficient, being below the values corresponding nominal ores, and in this case the thermal discharge systems of both tanks (15 and 22) are activated, providing the direct or low temperature mass flow of the remaining heat fluid to complete up to the nominal value of the mass flow rate provided by the solar collector battery (1), for which the pump (35) is activated and the valves (36) and (40) are opened; and the combined flow of heating fluid is heated, after that complementation, up to the nominal temperature value, by the action of the heat discharge exchanger (20) of indirect or high temperature storage, for which the valves (19) are opened and the pump (17) is activated; and by which, the mixture or joint flow of the mass flows, contributed from the battery of solar collectors (1) and from the direct storage, to the main exchanger (2), has not only the nominal mass flow, but the nominal temperature , which is verified by the meter (27).
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US20130307273A1 (en) * 2011-02-08 2013-11-21 Brightsource Industries (Israel) Ltd. Solar energy storage system including three or more reservoirs
WO2016150455A1 (en) * 2015-03-20 2016-09-29 Siemens Aktiengesellschaft System for storing thermal energy and method of operating a system for storing thermal energy

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US4400946A (en) * 1979-09-07 1983-08-30 Bbc Brown, Boveri & Company Limited Solar thermal power plant
FR2482205A1 (en) * 1980-05-08 1981-11-13 Electricite De France Electric power station using solar energy - which heats molten salt eutectic circulating through steam generator, so steam is obtd. to drive turbo:alternator
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WO2016150455A1 (en) * 2015-03-20 2016-09-29 Siemens Aktiengesellschaft System for storing thermal energy and method of operating a system for storing thermal energy

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