WO2012175763A1 - Storage of heat energy using a reversible steam condenser-generator - Google Patents

Storage of heat energy using a reversible steam condenser-generator Download PDF

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Publication number
WO2012175763A1
WO2012175763A1 PCT/ES2012/000155 ES2012000155W WO2012175763A1 WO 2012175763 A1 WO2012175763 A1 WO 2012175763A1 ES 2012000155 W ES2012000155 W ES 2012000155W WO 2012175763 A1 WO2012175763 A1 WO 2012175763A1
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WO
WIPO (PCT)
Prior art keywords
exchanger
tank
steam
reversible
fluid
Prior art date
Application number
PCT/ES2012/000155
Other languages
Spanish (es)
French (fr)
Inventor
José Maria MARTÍNEZ-VAL PEÑALOSA
Manuel VALDÉS DEL FRESNO
Alberto Abanades Velasco
Rafael Rubén AMENGUAL MATAS
Mireia Piera Carrete
Mária José MONTES PITA
Antonio Rovira De Antonio
Alberto RAMOS MILLÍAN
Javier MUÑOZ ANTÓN
Rubén ABBAS CÁMARA
Original Assignee
Universidad Politécnica de Madrid
Universidad Nacional De Educación A Distancia
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Filing date
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Application filed by Universidad Politécnica de Madrid, Universidad Nacional De Educación A Distancia filed Critical Universidad Politécnica de Madrid
Publication of WO2012175763A1 publication Critical patent/WO2012175763A1/en

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Classifications

    • 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
    • F01K9/00—Plants characterised by condensers arranged or modified to co-operate with the engines
    • 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
    • F01K3/006—Accumulators and steam compressors
    • 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

Definitions

  • the invention falls within the field of thermal engineering, and more specifically in installations where a high enthalpy steam is generated by any means, and said steam cannot be used in its entirety at any given time, so It has to relieve the atmosphere, if it cannot be stored.
  • An important case of this type is that of thermo-solar power plants, whether they are intended for electricity generation or direct thermal uses, typically of an industrial type.
  • the problem that is specifically to be solved is the storage of thermal energy from steam (mainly water vapor), and the thermal route to be proposed passes through the condensation of high pressure steam, by thermal transfer to a secondary fluid that is going to acquire at the condenser outlet a temperature not too far from that of water condensation, which occurs on the primary side of the condenser.
  • steam mainly water vapor
  • thermodynamically differentiated field such as subcooled, biphasic, and superheated steam
  • the invention consists in structuring a steam generation plant, for whatever use, including a central thermal storage system comprising:
  • a drum for the separation of saturated steam with three possible alternatives of exit, which correspond to: the recirculation of the liquid; to the steam duct towards its application or purpose; and to the steam duct towards a specific, reversible flow exchanger; - said heat exchanger, reversible flow both in its primary and secondary circuit, acting as a condenser when the primary fluid has a downward path, or acting as a steam generator when the primary fluid goes upward, having a structurally arranged vertical housing and tubes, the trunk tubes being conical, with the mouth of smaller diameter below, and said tubes going from a lower base plate to an upper base plate, and the primary fluid being the one circulating inside the tubes;
  • a secondary fluid subsystem of said reversible exchanger consisting of two storage tanks of the thermal fluid used, this fluid selected from oil and molten salts, or another substance that is liquid at the operating temperature level set at each
  • the tanks are connected by a conduit or pipe that crosses the reversible exchanger, one of them always acting as a low temperature tank, and another as a high temperature tank, with the secondary fluid from the low to high tank when the exchanger it acts as a condenser, and the secondary fluid from the tank goes from high to low when the exchanger acts as a steam generator;
  • the secondary fluid selected from molten salt, industrial oil or any other substance stable as a liquid at operating temperatures, moving from the outside of the tubes, between them and the housing, always predominantly vertical; an evacuation conduit from the separation drum, through the reversible exchanger primary circuit, to the condensate tank at high pressure and high temperature, this conduit being provided with a valve that is only open when the exchanger acts as a condenser;
  • a condensate evacuation pump in said evacuation duct which stimulates the rate of evacuated fluid, and maintains the level of the liquid free surface, in said reversible exchanger, at the height of the lower base plate of the exchanger, when it acts as condenser;
  • a vapor replacement duct which takes liquid from the condensate tank, injects it into the primary circuit of the reversible exchanger, which acts in the steam generator mode, and from which it emerges into the ordinary uses of the steam in the plant, this duct being provided with a valve that is only open when the exchanger acts as a steam generator; - an injection pump from the condensate tank to the primary circuit of the reversible exchanger, which maintains the level of the liquid-free surface, in the primary circuit of said exchanger, at the height of the upper base plate of the exchanger, when it It acts as a steam generator.
  • the drainage circuit is opened that diverts part or all of the steam produced to the primary circuit of the reversible heat exchanger, which currently acts as a condenser.
  • the entire surface of the frustoconical tubes inside which condensation occurs must be practically discovered of condensed liquid, since this is a thermal resistance for heat transfer that involves condensation.
  • the surface of the condensed liquid is carried and maintained just at the height, or a few centimeters below, of the bottom base plate of the exchanger, which is monitored with various techniques, both thermoelectric and electro-optical, as visual (in a bypass capillary with transparent cover slit).
  • An essential element for maintaining the level is the pump that drives the condensate from the base of the condenser to the pressure vessel of the condensate. If the condensed liquid accumulates in the condenser because it does not evacuate quickly enough, the level of liquid in the condenser would rise, cover part of the thermo-transfer surface and make condensation difficult. Therefore, if the free surface of the liquid rises above the lower base plate, the condensate extraction pump must act with more power, extracting more liquid flow, and lowering the level of the free surface; and reducing the suction power in the opposite case, extracting less liquid flow when the free surface falls below its set point, which is the lower base plate.
  • the pressure of said reservoir can be relaxed by partially opening the relief valve that connects it to the main condensate tank, which is at or near atmospheric pressure.
  • the heat recovered in that phase change is captured by the secondary fluid, which acts as a refrigerant, reaching a very high temperature, substantially 10 ° C below the fluid condensation temperature primary, and said secondary fluid passes from the low temperature tank, or cold tank, to the high temperature tank, or hot tank, (by actuating the cold tank pump), absorbing the heat released by the primary fluid in its condensation; leaving the primary fluid condensed at pressure and temperature equal to those of the primary steam, or somewhat lower, with a reduction of up to 5% in value relative to the pressure and temperature of the steam.
  • thermal storage is truly done in the oil or molten salt, although the condensed primary fluid is kept at pressure and temperature as high as possible and cost effective, to make steam generation easier, when it is demanded. in quantity greater than what the plant can give at that time, so it has to resort to stored thermal energy.
  • the injection pump is activated from the condensate tank to the primary circuit of the exchanger and the primary fluid circulates from the inside from bottom to top, always through inside the truncated conical tubes; and the criterion that the liquid-free surface is above the upper base plate is prescribed, which is monitored, by thermoelectric, or electro-optical or visual procedures. It is crucial here the role of said liquid injection pump from the high pressure condensate tank, which is given greater pumping power if it is desired to level up the liquid free surface, or otherwise, if desired that the level goes down, to stabilize in your reference, which is the upper base plate.
  • the discharge of secondary fluid from the hot tank to the lower temperature tank is activated, passing through the secondary circuit of the exchanger, activating the discharge pump of said hot tank.
  • thermocouples it is advisable to detect the appropriate level of protection against the boiling crisis, by applying active thermocouples to determine the local film coefficients at various heights, which will be very high, above 10,000 W / (m 2 K) if it is in the nucleated boiling regime, falling to 1,000 W / (m 2 K) or less if that surface is bathed only by dry steam.
  • the steam separates from the inner surface of the tubes, which is where their bubbles appear, which are enlarged as they rise in the breast of the liquid If it occurs in excess, the free surface of the liquid will descend, which can cause serious deterioration of the tubes in its exposed part.
  • the liquid injection pump is available from the condensate tank at high pressure, which is given greater pumping power if it is desired to level up the liquid free surface. During this operation, a high fraction of the heat stored in the hot tank is recovered, since from this it passes to the cold, yielding the heat necessary for the boiling of the primary liquid, whose vapor must be provided from the thermal storage.
  • the secondary fluid be it molten salt, industrial oil or any other substance, moves through the outside of the tubes, between them and the housing; and always moves in countercurrent.
  • the condensation function the primary descends and the secondary ascends; and the opposite in boiling.
  • Figure 1 shows the scheme of a steam plant, in this case to be used for expansion in a turbine, and to produce electricity. It is possibly the best example to demonstrate the parts and functionality of a thermal storage system.
  • Figure 2 shows the scheme of the vertical straight section of a reversible exchanger, which is the central element of the invention.
  • Figure 3 shows the straight cross section of the reversible exchanger, at the mouth level, distinguishing the lateral reinforcement crossings that should be placed between tubes, from the central tube, to maintain its geometry despite the pressure differences between the primary fluids and secondary.
  • Trunk tube inside which the primary fluid moves.
  • Lower base plate which closes spaces 55, and is welded to the bottom mouths of tubes 57.
  • Instruments for identifying the free surface of the liquid in the condensation which are monitors or meters of that level.
  • Instruments for identifying the free surface of the liquid in the boil which are monitors or meters of that level.
  • the invention has to be framed in a steam generation plant for a useful purpose, such as the generation of electricity, which is the case presented in Figure 1, and which brings together all the elements to explain the invention clearly, starting with note that the invention itself is the thermal storage system consisting of:
  • the reversible exchanger 17 which is properly the component specifically designed for this invention, and which is described below with the required detail. Its primary fluid is the vapor that reaches it to condense, or that is generated within it when it operates in the generation mode.
  • the enthalpy of the available saturated steam is achieved in two ways: the condensate of the primary fluid itself, which is kept at high pressure and temperature; and the heated secondary fluid, which is stored in the high T tank.
  • the excess steam of the drum 10 is condensed practically at the pressure that it has, thanks to the secondary fluid, and to the heat transfer carried out in the exchanger.
  • the secondary fluid passes from the low temperature tank, or cold tank, to the high temperature tank, or hot tank, absorbing the heat released by the primary fluid in its condensation.
  • the generation mode is activated, and the contents of the hot tank, 19, are discharged through the circuit 20, which has as main part the secondary of the exchanger 17, to arrive, cooled , to the low T storage tank, 18.
  • heat is transferred to the liquid injected into the primary of the exchanger 7 from the high pressure condensate tank, which is where the primary fluid is collected in the condensation mode.
  • the reversible exchanger 17 corresponds to a general type of casing and tubes, but with a special configuration, deduced from the functions to be fulfilled.
  • the level monitors, 66 and 67 respectively near or slightly below the lower base plate (58) for condensation mode, and near or slightly above the upper base plate (59) for the boiling mode
  • These level meters can be of the active thermocouple type, which measure the value of the film coefficient, which is really the variable to be monitored, since what has to be avoided, particularly in boiling, is that the appearance of a film Dry steam on the contact surface greatly reduces the value of that coefficient, and that greatly impairs heat transfer and efficiency in the process is lost; although it should be noted that in this case, in which the heat input comes from a fluid, the secondary one, whose temperature is given, the "dry out" phenomenon feared in the nuclear fuel pods in the LWR reactors cannot occur, because in the reactors the power generated within the fuel must be extracted and the temperature is not limited.
  • the value of h 2 ' ⁇ which is the thermal resistance of the secondary film will be the largest of the three addends of the right member in the equation previous, that defined U "1 , and therefore U. That means that the value U will be close to ah 2 , but less than him.
  • the value of U must be made as high as possible, because it intervenes in the determination of the size of the exchanger 17, since it is conditioned to the heat transfer area A which is defined as a function of the height H between the two base plates, the number of truncated conical tubes, N, and the upper diameters D s and lower D ⁇ of said tubes, being
  • m is defined as a function of the condensation temperature of the primary T c , that of the secondary fluid in the high T 2a tank and that of the secondary fluid in the low T 2b tank
  • the thermal power Q meets the energy balance in the secondary fluid, depending on its mass flow m 2 and the specific heat C 2 of the secondary fluid
  • the boiling temperature of the primary T e will be less than T 2b , in the same way as in the condensation mode, the temperature T c is above T 2a . This leads to the loss of exergy due to the process of loading and unloading storage can be characterized by
  • m 2 is essential to reduce the loss of exergy; but it must be taken into account that this value also influences the size of the exchanger, particularly in its straight section, which is the sum of the straight section of the tubes through which the primary circulates, plus the straight section of the secondary S 2 .
  • the latter is linked to am 2 by the equation in which the density of the secondary p 2 and its velocity v 2 intervene
  • the option of boosting the secondary with a v 2 involves the problem of a strong loss of manometric load, and therefore high pumping power, so that the particular realization of an exchanger will have to be done by adding some optimization criteria, or by performing a Cost-benefit analysis between investment cost and operating cost, which escapes the scope of a patent. It is, however, relevant for the design to take into account that the film coefficient h 2 is not uniform, but depends on the hydraulic conditions at each point, in particular the speed.
  • r is the ratio between outside and inside diameters of the tank.
  • the admissible ⁇ is less than usual at room temperature, since the elastic period is shortened and the risk of creep approaches, if Pi is high, close to 10 MPa, for example, the ratio ⁇ / ⁇ Allowable is low, around 6.
  • the thickness of the tank must be greater than 9% of the inside diameter. If the wall of the tank is bounded at a thickness of 10 cm, the inner diameter would be approximately 1 meter. This means that the exchanger must be slender, which is a well known reality.
  • An emblematic case is that of the PWR nuclear reactor steam generators, in which the pressure is around 7 MPa (and they have no other function, nor are they reversible).

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)

Abstract

The invention relates to a system for the storage of heat energy in plants that produce steam, generally at high or very high pressure, based on the condensation of the steam at high pressure and high temperature. According to the invention, the secondary is a fluid medium selected from molten salt, thermal oil or another liquid having stable properties under these conditions and, during such an operation, the fluid medium passes from the low-temperature tank to the high-temperature tank, such that practically all of the condensation heat is extracted by said medium, which heat is recovered, although at a somewhat lower temperature, when the exchanger operates as a steam generator. The aforementioned exchanger has frustoconical vertical tubes in order to improve the performance thereof.

Description

ALMACENAMIENTO DE ENERGÍA TÉRMICA MEDIANTE CONDENSADOR- STORAGE OF THERMAL ENERGY THROUGH CONDENSER-
GENERADOR DE VAPOR REVERSIBLE REVERSIBLE STEAM GENERATOR
SECTOR DE LA TÉCNICA SECTOR OF THE TECHNIQUE
La invención se encuadra en el campo de la ingeniería térmica, y más concretamente en las instalaciones en las que se genera un vapor de alta entalpia por cualquier medio, y dicho vapor no puede usarse en su totalidad en un momento dado, por lo que se ha de aliviar a la atmósfera, si no se puede almacenar. Un importante caso de este tipo es el de las centrales termo-solares, tanto si están destinadas para generación de electricidad como a usos térmicos directos, típicamente de tipo industrial.  The invention falls within the field of thermal engineering, and more specifically in installations where a high enthalpy steam is generated by any means, and said steam cannot be used in its entirety at any given time, so It has to relieve the atmosphere, if it cannot be stored. An important case of this type is that of thermo-solar power plants, whether they are intended for electricity generation or direct thermal uses, typically of an industrial type.
PROBLEMA TÉCNICO A RESOLVER Y ANTECEDENTES DE LA INVENCIÓN TECHNICAL PROBLEM TO BE RESOLVED AND BACKGROUND OF THE INVENTION
Hay varios ámbitos industriales donde se dispone de una fuente de calor que no es totalmente regulable o gestionable por el operador de la planta, como es el caso, muy señalado dentro de las energías renovables, de las instalaciones termosolares de alta temperatura, especialmente si están destinadas a la generación de electricidad. En estas plantas, la turbina tiene una potencia máxima, normalmente no muy por encima de la potencia nominal, y de manera habitual no se puede exceder de ésta; mientras que la radiación solar recibida en el campo de colectores varía diurnamente y estacionalmente, de tal modo que sólo en contados momentos coincide la potencia térmica captada por los colectores con la que necesita la turbina para su funcionamiento nominal; y dicha potencia térmica colectada está, o bien por debajo, en cuyo caso hay que trabajar a potencia parcial, o bien está por encima, en cuyo caso se trabaja a la potencia nominal, o eventualmente a la máxima permitida, y queda un exceso de vapor que, si no se puede destinar a otro fin, se ha de evacuar a la atmósfera, salvo que se pueda almacenar, bien como tal vapor, bien indirectamente, transfiriendo su energía térmica a un medio que sea más eficiente en ese tipo de función térmica.  There are several industrial areas where a heat source is available that is not fully adjustable or manageable by the plant operator, as is the case, very marked within renewable energies, of high-temperature solar thermal installations, especially if they are intended for the generation of electricity. In these plants, the turbine has a maximum power, normally not well above the nominal power, and usually cannot be exceeded; while the solar radiation received in the field of collectors varies day and seasonally, so that only in a few moments does the thermal power captured by the collectors coincide with what the turbine needs for its nominal operation; and said collected thermal power is either below, in which case it is necessary to work at partial power, or it is above, in which case the nominal power is worked, or possibly at the maximum allowed, and an excess of steam that, if it cannot be used for another purpose, must be evacuated to the atmosphere, unless it can be stored, either as such steam, or indirectly, transferring its thermal energy to a medium that is more efficient in that type of function thermal
El problema que específicamente se quiere resolver es el del almacenamiento de energía térmica a partir de vapor (fundamentalmente, vapor de agua), y la ruta térmica que se va a proponer pasa por la condensación del vapor a alta presión, por transferencia térmica a un fluido secundario que va a adquirir a la salida del condensador una temperatura no muy lejana de la de condensación del agua, que ocurre en el lado primario del condensador. The problem that is specifically to be solved is the storage of thermal energy from steam (mainly water vapor), and the thermal route to be proposed passes through the condensation of high pressure steam, by thermal transfer to a secondary fluid that is going to acquire at the condenser outlet a temperature not too far from that of water condensation, which occurs on the primary side of the condenser.
Eso significa que habrá en realidad dos áreas técnicas a considerar: la del almacenamiento térmico en sí, en particular el que se produce con cambio de fase, y la de los condensadores de vapor.  That means that there will actually be two technical areas to consider: that of thermal storage itself, in particular that which occurs with phase change, and that of steam condensers.
Se han analizado invenciones en ambos campos, y particularmente en el primero de ellos es de señalar la invención solicitada en WO 2010085574 (A1) destinada al almacenamiento térmico compatible con vapor sobrecalentado. En concreto, la invención define un método para cada ámbito termodinámicamente diferenciado, como es el subenfriado, el bifásico, y el vapor sobrecalentado, de modo que a lo que atiende es a un sistema en su conjunto, más que a dispositivos concretos para materializar las ideas.  Inventions have been analyzed in both fields, and particularly in the first one, it is worth noting the invention requested in WO 2010085574 (A1) for thermal storage compatible with superheated steam. Specifically, the invention defines a method for each thermodynamically differentiated field, such as subcooled, biphasic, and superheated steam, so that what it addresses is a system as a whole, rather than specific devices for materializing ideas.
En algunos casos se propone, para almacenar energía térmica a alta temperatura, el uso de sistemas con cambio de fase en el medio secundario, que es donde se realiza el almacenamiento, y en tal sentido cabe mencionar la US 4696338 (A), que usa un tanque con líquido y vapor en equilibrio, a alta presión y temperatura, parecido a los presionadores de los reactores nucleares PWR; pero el sistema adolece de falta de capacidad, por almacenar vapor, con su consiguiente alto valor de volumen específico, lo que significa que la masa total de agua/vapor almacenada está muy acotada. También existe el precedente de que el medio secundario no cambie de sólido a líquido, como es el caso propuesto en WO 0212814 (A1). Como variante curiosa de ésta se emplean cristales de algunas sustancias, como son los clatratos, y en tal sentido cabe citar la US 4821794 (A).  In some cases it is proposed, to store thermal energy at high temperature, the use of systems with phase change in the secondary medium, which is where the storage is carried out, and in this sense it is worth mentioning US 4696338 (A), which uses a tank with liquid and vapor in equilibrium, at high pressure and temperature, similar to the pressures of the PWR nuclear reactors; but the system suffers from lack of capacity, for storing steam, with its consequent high specific volume value, which means that the total mass of water / steam stored is very limited. There is also a precedent that the secondary medium does not change from solid to liquid, as is the case proposed in WO 0212814 (A1). As a curious variant of this, crystals of some substances are used, such as clathrates, and in that sense, US 4821794 (A) should be mentioned.
Hay algunas invenciones propuestas para plantas solares, como el sistema de captación solar y almacenamiento presentado en CN 101846044, o el dispositivo Fresnel de reflexión con sales fundidas en su tubo focal, GR 20090100177(a).  There are some proposed inventions for solar plants, such as the solar collection and storage system presented in CN 101846044, or the Fresnel reflection device with molten salts in its focal tube, GR 20090100177 (a).
Y en el ámbito de los equipos en sí mismos, es de señalar el documento US 2010319879 (A1) sobre un condensador multi-presión, compuesto en realidad por dos cámaras de condensación consecutivas, y posible recirculación entre ellas. Como la mayor parte de las invenciones propuestas en este campo, se centran en mejorar las prestaciones de las turbinas, y no en aprovechar la condensación para almacenar energía térmica. Como antecedentes más cercanos al equipamiento objeto de la invención, pero sin atisbarse de ninguna manera el condensador-generador reversible actuando a alta presión, cabe citar los documentos CN 101845973, que presenta un drenaje vertical de la turbina (ideado sobre todo para reacción ante emergencias), el documento CN 201191110 (Y) que presenta un condensador de tubos verticales, y el JP 2009174437 (A) que contiene un condensador en forma de torre, con tubos así mismo verticales. And in the field of the equipment itself, it is worth noting the document US 2010319879 (A1) on a multi-pressure condenser, actually composed of two consecutive condensing chambers, and possible recirculation between them. Like most of the inventions proposed in this field, they focus on improving turbine performance, and not taking advantage of condensation to store thermal energy. As background closer to the equipment object of the invention, but without any glimpse of the reversible condenser-generator operating at high pressure, it is worth mentioning documents CN 101845973, which presents a vertical drainage of the turbine (designed especially for emergency response ), document CN 201191110 (Y) which presents a vertical tube condenser, and JP 2009174437 (A) containing a tower-shaped condenser, with vertical tubes.
En realidad, una amplia gama de intercambiadores de calor para diversos objetivos corresponde a la clase de tubos y carcasa, con paso simple o múltiple; tanto de disposición horizontal como vertical. Una guía práctica sobre estos intercambiadores son las normas TEMA (Tubular Exchanger Manufacturar Association) pero aún siendo tan bien conocidos, aún parece haber sitio para la invención y el uso innovador de las invenciones en el mundo de los intercambiadores.  In reality, a wide range of heat exchangers for various purposes corresponds to the class of tubes and housing, with single or multiple passage; both horizontal and vertical layout. A practical guide on these exchangers is the TEMA (Tubular Exchanger Manufacturing Association) standards but still being so well known, there still seems to be room for the invention and innovative use of inventions in the world of exchangers.
Respecto de las funciones en sí, también hay precedentes de uso alternativo de un intercambiador para condensar o para generar vapor. Una propuesta de este tipo es la del documento WO 2010013608 (A1), aunque se trata en su caso de un intercambiador de placas, de geometría totalmente distinta de la de tubos y carcasa, siendo además los de placas poco adecuados para trabajar con diferencias de presión altas, entre primario y secundario.  Regarding the functions themselves, there are also precedents for the alternative use of an exchanger to condense or generate steam. A proposal of this type is that of WO 2010013608 (A1), although it is a plate exchanger, with a totally different geometry from that of tubes and casing, being also those of plates not very suitable for working with differences of high pressure, between primary and secondary.
DESCRIPCIÓN DE LA INVENCIÓN  DESCRIPTION OF THE INVENTION
La invención consiste en estructurar una planta de generación de vapor, para el uso que sea, con inclusión de un sistema central de almacenamiento térmico que comprende:  The invention consists in structuring a steam generation plant, for whatever use, including a central thermal storage system comprising:
- un tambor de separación del vapor saturado, con tres posibles alternativas de salida, que corresponden a: la recirculación del líquido; al conducto de vapor hacia su aplicación o finalidad; y al conducto de vapor hacia un intercambiador específico, de flujo reversible; - dicho intercambiador de calor, de flujo reversible tanto en su circuito primario como en el secundario, actuando como condensador cuando el fluido primario tiene una trayectoria descendente, o actuando como generador de vapor cuando el fluido primario va en trayectoria ascendente, teniendo estructuralmente una disposición vertical de carcasa y tubos, siendo los tubos troncocónicos, con la boca de menor diámetro abajo, y yendo dichos tubos desde una placa base inferior a una placa base superior, y siendo el fluido primario el que circula por dentro de los tubos; - a drum for the separation of saturated steam, with three possible alternatives of exit, which correspond to: the recirculation of the liquid; to the steam duct towards its application or purpose; and to the steam duct towards a specific, reversible flow exchanger; - said heat exchanger, reversible flow both in its primary and secondary circuit, acting as a condenser when the primary fluid has a downward path, or acting as a steam generator when the primary fluid goes upward, having a structurally arranged vertical housing and tubes, the trunk tubes being conical, with the mouth of smaller diameter below, and said tubes going from a lower base plate to an upper base plate, and the primary fluid being the one circulating inside the tubes;
un subsistema del fluido secundario de dicho intercambiador reversible, consistente en dos tanques de almacenamiento del fluido térmico que se use, seleccionado este fluido entre aceite y sales fundidas, u otra sustancia que sea líquida en el nivel de temperaturas de operación que se fije en cada caso, estando unidos los tanques por un conducto o tubería que atraviesa el intercambiador reversible, actuando siempre uno de ellos como tanque de baja temperatura, y otro como tanque de alta temperatura, yendo el fluido secundario del tanque de baja al de alta cuando el intercambiador actúa como condensador, y yendo el fluido secundario del tanque de alta al de baja cuando el intercambiador actúa como generador de vapor; moviéndose el fluido secundario, seleccionado entre sal fundida, aceite industrial o cualquier otra sustancia estable como líquido a las temperaturas de operación, por la parte exterior de los tubos, entre éstos y la carcasa, siempre de forma predominantemente vertical; un conducto de evacuación desde el tambor de separación, a través del circuito primario intercambiador reversible, hasta el depósito de condensado a alta presión y alta temperatura, estando provisto este conducto de una válvula que sólo está abierta cuando el intercambiador actúa como condensador; a secondary fluid subsystem of said reversible exchanger, consisting of two storage tanks of the thermal fluid used, this fluid selected from oil and molten salts, or another substance that is liquid at the operating temperature level set at each In this case, the tanks are connected by a conduit or pipe that crosses the reversible exchanger, one of them always acting as a low temperature tank, and another as a high temperature tank, with the secondary fluid from the low to high tank when the exchanger it acts as a condenser, and the secondary fluid from the tank goes from high to low when the exchanger acts as a steam generator; the secondary fluid, selected from molten salt, industrial oil or any other substance stable as a liquid at operating temperatures, moving from the outside of the tubes, between them and the housing, always predominantly vertical; an evacuation conduit from the separation drum, through the reversible exchanger primary circuit, to the condensate tank at high pressure and high temperature, this conduit being provided with a valve that is only open when the exchanger acts as a condenser;
un depósito de condensado a alta presión y alta temperatura; a high pressure and high temperature condensate tank;
una bomba de evacuación del condensado en dicho conducto de evacuación, que estimula la tasa de fluido evacuado, y mantiene el nivel de la superficie libre de líquido, en dicho intercambiador reversible, a la altura de la placa base inferior del intercambiador, cuando éste actúa como condensador; a condensate evacuation pump in said evacuation duct, which stimulates the rate of evacuated fluid, and maintains the level of the liquid free surface, in said reversible exchanger, at the height of the lower base plate of the exchanger, when it acts as condenser;
un conducto de reposición del vapor, que toma líquido desde el depósito de condensado, lo inyecta en el circuito primario del intercambiador reversible, que actúa en el modo de generador de vapor, y del cual emerge hacia los usos ordinarios del vapor que haya en la planta, estando provisto este conducto de una válvula que sólo está abierta cuando el intercambiador actúa como generador de vapor; - una bomba de inyección desde el depósito de condensado hasta el circuito primario del intercambiador reversible, que mantiene el nivel de la superficie libre de líquido, en el circuito primario de dicho intercambiador, a la altura de la placa base superior del intercambiador, cuando éste actúa como generador de vapor.a vapor replacement duct, which takes liquid from the condensate tank, injects it into the primary circuit of the reversible exchanger, which acts in the steam generator mode, and from which it emerges into the ordinary uses of the steam in the plant, this duct being provided with a valve that is only open when the exchanger acts as a steam generator; - an injection pump from the condensate tank to the primary circuit of the reversible exchanger, which maintains the level of the liquid-free surface, in the primary circuit of said exchanger, at the height of the upper base plate of the exchanger, when it It acts as a steam generator.
Cuando en la planta hay excedente de vapor, se abre el circuito de drenaje que desvía parte o todo el vapor producido al circuito primario del intercambiador de calor reversible, que en esos momentos actúa como condensador. Para ello, toda la superficie de los tubos troncocónicos por dentro de los cuales se produce la condensación, ha de estar prácticamente descubierta de líquido condensado, pues éste es una resistencia térmica para la transferencia de calor que implica la condensación. Para ello se lleva y mantiene la superficie del líquido condensado justo a la altura, o algunos centímetros por debajo, de la placa base inferior del intercambiador, lo cual se monitoriza con diversa técnicas, tanto termoeléctricas como electro-ópticas, como visuales (en un capilar de derivación con hendidura de cubierta transparente). Un elemento esencial para mantener el nivel es la bomba que impulsa el condensado desde la base del condensador hasta el depósito a presión del condensado. Si el líquido condensado se acumulase en el condensador porque no se evacúa suficientemente rápido, subiría el nivel de líquido en el condensador, cubriría parte de la superficie de termo-transferencia y se dificultaría la condensación. Por ello, si la superficie libre del líquido sube por encima de la placa base inferior, la bomba de extracción del condensado ha de actuar con más potencia, extrayendo más caudal de líquido, y bajando el nivel de la superficie libre; y reduciendo la potencia de succión en caso contrario, extrayendo menos caudal de líquido cuando la superficie libre desciende de su nivel de consigna, que es la placa base inferior. When there is a surplus of steam in the plant, the drainage circuit is opened that diverts part or all of the steam produced to the primary circuit of the reversible heat exchanger, which currently acts as a condenser. To do this, the entire surface of the frustoconical tubes inside which condensation occurs must be practically discovered of condensed liquid, since this is a thermal resistance for heat transfer that involves condensation. For this, the surface of the condensed liquid is carried and maintained just at the height, or a few centimeters below, of the bottom base plate of the exchanger, which is monitored with various techniques, both thermoelectric and electro-optical, as visual (in a bypass capillary with transparent cover slit). An essential element for maintaining the level is the pump that drives the condensate from the base of the condenser to the pressure vessel of the condensate. If the condensed liquid accumulates in the condenser because it does not evacuate quickly enough, the level of liquid in the condenser would rise, cover part of the thermo-transfer surface and make condensation difficult. Therefore, if the free surface of the liquid rises above the lower base plate, the condensate extraction pump must act with more power, extracting more liquid flow, and lowering the level of the free surface; and reducing the suction power in the opposite case, extracting less liquid flow when the free surface falls below its set point, which is the lower base plate.
En caso necesario, pero esto no es parte de la invención, se puede relajar la presión de dicho depósito abriendo parcialmente la válvula de alivio que lo conecta con el tanque principal de condensado, que está a presión atmosférica, o cercana a ella.  If necessary, but this is not part of the invention, the pressure of said reservoir can be relaxed by partially opening the relief valve that connects it to the main condensate tank, which is at or near atmospheric pressure.
Durante el funcionamiento del intercambiador como condensador, el calor recuperado en ese cambio de fase es captado por el fluido secundario, que actúa de refrigerante, alcanzando una temperatura muy elevada, sustancialmente 10 °C por debajo de la temperatura de condensación del fluido primario, y pasa dicho fluido secundario del tanque de baja temperatura, o tanque frío, al tanque de alta temperatura, o tanque caliente, (por accionamiento de la bomba del tanque frío), absorbiendo el calor liberado por el fluido primario en su condensación; dejando al fluido primario condensado a presión y temperatura iguales a las que tenía el vapor primario, o algo menores, con una reducción de hasta el 5% en valor relativo a la presión y temperatura del vapor. Eso significa que el almacenamiento térmico se hace verdaderamente en el aceite o en la sal fundida, aunque el fluido primario condensado se mantiene a presión y temperatura tan altas como sea posible y rentable, para hacer más fácil la generación de vapor, cuando éste se demanda en cantidad superior a lo que puede dar la planta en ese momento, por lo que se ha de recurrir a la energía térmica almacenada. During the operation of the exchanger as a condenser, the heat recovered in that phase change is captured by the secondary fluid, which acts as a refrigerant, reaching a very high temperature, substantially 10 ° C below the fluid condensation temperature primary, and said secondary fluid passes from the low temperature tank, or cold tank, to the high temperature tank, or hot tank, (by actuating the cold tank pump), absorbing the heat released by the primary fluid in its condensation; leaving the primary fluid condensed at pressure and temperature equal to those of the primary steam, or somewhat lower, with a reduction of up to 5% in value relative to the pressure and temperature of the steam. That means that thermal storage is truly done in the oil or molten salt, although the condensed primary fluid is kept at pressure and temperature as high as possible and cost effective, to make steam generation easier, when it is demanded. in quantity greater than what the plant can give at that time, so it has to resort to stored thermal energy.
En este último caso tiene lugar la operación contraria, y el intercambiador actúa de generador de vapor, activándose la bomba de inyección desde el depósito de condensado hasta el circuito primario del intercambiador y el fluido primario circula por su interior de abajo a arriba, siempre por dentro de los tubos troncocónicos; y se prescribe el criterio de que la superficie libre de líquido esté por encima de la placa base superior, lo cual se monitoriza, por procedimientos termo eléctricos, o electro-ópticos o visuales. Es crucial aquí el papel de dicha bomba de inyección de líquido desde el depósito de condensado a alta presión, a la que se le proporciona mayor potencia de bombeo si se desea subir de nivel la superficie libre de líquido, o lo contrario, si se desea que el nivel baje, para estabilizarse en su referencia, que es la placa base superior. Por otro lado, y al mismo tiempo, se activa la descarga de fluido secundario desde el tanque caliente hasta el tanque de menor temperatura, pasando a través del circuito secundario del intercambiador, activándose la bomba de descarga de dicho tanque caliente.  In the latter case the opposite operation takes place, and the exchanger acts as a steam generator, the injection pump is activated from the condensate tank to the primary circuit of the exchanger and the primary fluid circulates from the inside from bottom to top, always through inside the truncated conical tubes; and the criterion that the liquid-free surface is above the upper base plate is prescribed, which is monitored, by thermoelectric, or electro-optical or visual procedures. It is crucial here the role of said liquid injection pump from the high pressure condensate tank, which is given greater pumping power if it is desired to level up the liquid free surface, or otherwise, if desired that the level goes down, to stabilize in your reference, which is the upper base plate. On the other hand, and at the same time, the discharge of secondary fluid from the hot tank to the lower temperature tank is activated, passing through the secondary circuit of the exchanger, activating the discharge pump of said hot tank.
En particular es recomendable la detección del nivel adecuado de protección contra la crisis de ebullición, mediante la aplicación de termopares activos para determinar los coeficientes de película locales a diversas alturas, que serán muy elevados, por encima de 10.000 W/(m2 K) si se está en el régimen de ebullición nucleada, cayendo a 1.000 W/(m2 K) o menos en caso de estar bañada esa superficie sólo por vapor seco. In particular, it is advisable to detect the appropriate level of protection against the boiling crisis, by applying active thermocouples to determine the local film coefficients at various heights, which will be very high, above 10,000 W / (m 2 K) if it is in the nucleated boiling regime, falling to 1,000 W / (m 2 K) or less if that surface is bathed only by dry steam.
El vapor se separa de la superficie interior de los tubos, que es donde aparecen sus burbujas, que se van agrandando a medida que suben en el seno del líquido. Si se produce en exceso, la superficie libre del líquido descenderá, lo cual puede motivar un serio deterioro de los tubos en su parte descubierta. Para controlar este efecto, se dispone de la bomba de inyección de líquido desde el depósito de condensado a alta presión, a la que se le proporciona mayor potencia de bombeo si se desea subir de nivel la superficie libre de líquido. Durante esta operación, se recupera una alta fracción del calor almacenado en el tanque caliente, pues desde éste pasa al frío, cediendo el calor necesario para la ebullición del líquido del primario, cuyo vapor hay que proporcionar desde el almacenamiento térmico. The steam separates from the inner surface of the tubes, which is where their bubbles appear, which are enlarged as they rise in the breast of the liquid If it occurs in excess, the free surface of the liquid will descend, which can cause serious deterioration of the tubes in its exposed part. To control this effect, the liquid injection pump is available from the condensate tank at high pressure, which is given greater pumping power if it is desired to level up the liquid free surface. During this operation, a high fraction of the heat stored in the hot tank is recovered, since from this it passes to the cold, yielding the heat necessary for the boiling of the primary liquid, whose vapor must be provided from the thermal storage.
En todos los casos, el fluido secundario, sea sal fundida, aceite industrial o cualquier otra sustancia, se mueve por la parte exterior de los tubos, entre éstos y la carcasa; y siempre se mueve en contracorriente. En la función de condensación, el primario desciende y el secundario asciende; y lo opuesto en la ebullición.  In all cases, the secondary fluid, be it molten salt, industrial oil or any other substance, moves through the outside of the tubes, between them and the housing; and always moves in countercurrent. In the condensation function, the primary descends and the secondary ascends; and the opposite in boiling.
BREVE DESCRIPCIÓN DE LAS FIGURAS BRIEF DESCRIPTION OF THE FIGURES
La figura 1 muestra el esquema de una planta de vapor, en este caso para ser usada su expansión en una turbina, y producir electricidad. Es posiblemente el mejor ejemplo para evidenciar las partes y funcionalidad de un sistema de almacenamiento térmico.  Figure 1 shows the scheme of a steam plant, in this case to be used for expansion in a turbine, and to produce electricity. It is possibly the best example to demonstrate the parts and functionality of a thermal storage system.
La figura 2 muestra el esquema de la sección recta vertical de un intercambiador reversible, que es el elemento central de la invención.  Figure 2 shows the scheme of the vertical straight section of a reversible exchanger, which is the central element of the invention.
La figura 3 muestra la sección recta transversal del intercambiador reversible, a nivel de la embocadura, distinguiéndose los travesanos de refuerzo lateral que conviene poner entre tubos, desde el tubo central, para mantener su geometría a pesar de las diferencias de presión entre los fluidos primario y secundario.  Figure 3 shows the straight cross section of the reversible exchanger, at the mouth level, distinguishing the lateral reinforcement crossings that should be placed between tubes, from the central tube, to maintain its geometry despite the pressure differences between the primary fluids and secondary.
MODOS PREFERENTES DE REALIZACIÓN DE LA INVENCIÓN  PREFERRED EMBODIMENTS OF THE INVENTION
Para facilitar la comprensión de las materializaciones preferentes de la invención, a continuación se relacionan los elementos relevantes de la misma, que aparecen en las figuras:  To facilitate the understanding of the preferred embodiments of the invention, the relevant elements thereof, which appear in the figures, are listed below:
1. Turbina.  1. Turbine.
2. Alternador.  2. Alternator.
3. Condensador del ciclo de Rankine. 4. Circuito de refrigeración del condensador del ciclo de Rankine. 3. Rankine cycle condenser. 4. Condenser cooling circuit of the Rankine cycle.
5. Depósito de condensado a baja presión.  5. Condensate tank at low pressure.
6. Válvula de regulación del flujo de condensado a baja presión.  6. Low pressure condensate flow regulating valve.
7. Bomba del condensado a baja presión.  7. Condensate pump at low pressure.
8. Aportación de calor para pre-calentamiento. 8. Heat supply for pre-heating.
Θ. Aportación de calor para la ebullición del fluido de trabajo, que es además el fluido primario en el intercambiador de calor reversible.  Θ Heat supply for the boiling of the working fluid, which is also the primary fluid in the reversible heat exchanger.
10. Tambor de separación bifásica.  10. Biphasic separation drum.
11. Tubería de recirculación de líquido en 9.  11. Liquid recirculation pipe in 9.
12. Válvula de regulación del flujo de recirculación 1 1. 12. Recirculation flow regulation valve 1 1.
13. Válvula de paso del vapor separado en el tambor 10.  13. Vapor stop valve separated in drum 10.
1 . Válvula de regulación del flujo de vapor que va al sobrecalentamiento. one . Valve regulating the flow of steam that goes to overheating.
15. Aportación de calor para el sobrecalentamiento. 15. Heat input for overheating.
16. Válvula de regulación del flujo de vapor que va al sistema de almacenamiento térmico.  16. Steam flow regulation valve that goes to the thermal storage system.
17. Intercambiador de calor reversible, condensador/generador de vapor. 17. Reversible heat exchanger, condenser / steam generator.
18. Tanque de fluido secundario, de baja temperatura relativa. 18. Secondary fluid tank, low relative temperature.
19. Tanque de fluido secundario, de alta temperatura relativa.  19. Secondary fluid tank, high relative temperature.
20. Circuito del fluido secundario del intercambiador 17, que conecta entre sí los tanques 18 y 19, y compre el lado secundario del intercambiador 17, que es el espacio entre los tubos y la carcasa.  20. Circuit of the secondary fluid of the exchanger 17, which connects the tanks 18 and 19 to each other, and buy the secondary side of the exchanger 17, which is the space between the tubes and the housing.
21. Bomba del tanque caliente.  21. Hot tank pump.
22. Tubo de descarga de fluido en el tanque caliente.  22. Fluid discharge tube in the hot tank.
23. Bomba del tanque frío.  23. Cold tank pump.
24. Tubo de descarga de fluido en el tanque frío. 24. Fluid discharge tube in the cold tank.
25. Válvula de regulación del flujo de condensado que va al depósito de alta presión del sistema de almacenamiento térmico.  25. Condensate flow regulating valve that goes to the high pressure reservoir of the thermal storage system.
26. Bomba del ramal de flujo de condensado que va al depósito de alta presión. 27. Depósito de condensado de alta presión del sistema de almacenamiento térmico. 26. Condensate flow branch pump that goes to the high pressure tank. 27. High pressure condensate tank of the thermal storage system.
28. Válvula de paso del depósito de alta presión (27) al de baja presión (5). 28. High pressure reservoir flow valve (27) to low pressure (5).
29. Boca de succión en el depósito del condensado de alta presión. 29. Suction nozzle in the high pressure condensate tank.
30. Válvula de regulación de flujo de condensado de alta presión. 30. High pressure condensate flow regulation valve.
31. Bomba de condensado de alta presión.  31. High pressure condensate pump.
32. Válvula de cierre del circuito de inyección de condensado a alta presión. 32. High pressure condensate injection circuit shut-off valve.
33. Ramal reversible de la boca de líquido del intercambiador 17. 33. Reversible branch of the liquid mouth of the exchanger 17.
34. Ramal de descarga de la boca de vapor del intercambiador 17.  34. Discharge branch of the steam nozzle of the exchanger 17.
35. Válvula del ramal 34. 35. Branch valve 34.
36. Ramal de descarga de vapor del ¡ntercambiador 17 en la aportación de calor para el sobrecalentamiento.  36. Steam discharge branch of exchanger 17 in the heat supply for overheating.
37. Válvula del ramal 36.  37. Branch valve 36.
38. Ramal de descarga del depósito de alta presión al de baja presión.  38. Discharge branch of the high pressure to the low pressure tank.
39. Ramal de descarga de vapor del intercambiador 17 en la turbina 1. 39. Steam discharge branch of exchanger 17 in turbine 1.
40. Válvula del ramal 39.  40. Branch valve 39.
41. Ramal de paso del depósito de condensado de baja presión al de alta. 41. Branch line of the low pressure condensate tank to the high one.
42. Válvula del ramal 41. 42. Branch valve 41.
43. Bomba del ramal 41.  43. Branch pump 41.
44. Ramal de paso del vapor del tambor 10 a la aportación de calor para sobrecalentamiento. 44. Branch of steam passage from drum 10 to heat supply for overheating.
45. Ramal de evacuación del vapor del tambor 10 al intercambiador 17. 45. Steam evacuation branch from drum 10 to exchanger 17.
46. Boca de vapor o superior del intercambiador 17. 46. Steam nozzle or top of the exchanger 17.
47. Boca de líquido o inferior del intercambiador 17.  47. Liquid mouth or bottom of the exchanger 17.
48. Cabezal superior del intercambiador 17. 48. Upper exchanger head 17.
49. Cabezal inferior del intercambiador 17.  49. Lower exchanger head 17.
50. Barrilete de presión del intercambiador 17.  50. Exchanger pressure keg 17.
51. Estructura soporte del intercambiador 17. 52. Rodillos de la estructura soporte del intercambiador 17. 51. Exchanger support structure 17. 52. Rollers of the exchanger support structure 17.
53. Boca del fluido secundario que da al tanque de baja temperatura relativa. 53. Mouth of the secondary fluid that gives the tank a low relative temperature.
54. Boca del fluido secundario que da al tanque de alta temperatura relativa.54. Mouth of the secondary fluid that gives the tank a high relative temperature.
55. Espacios de paso del fluido secundario dentro del intercambiador 17, que rellenan los huecos dejados por los tubos del primario. 55. Secondary fluid passage spaces within the exchanger 17, which fill the gaps left by the primary tubes.
56. Travesaños de refuerzo lateral de las paredes de los tubos troncocónicos. 56. Side reinforcement crossbars of the walls of the conical tubes.
57. Tubo troncocónico, por dentro del cual se mueve el fluido primario. 57. Trunk tube, inside which the primary fluid moves.
58. Placa base inferior, que cierra los espacios 55, y va soldada a las bocas inferiores de los tubos 57.  58. Lower base plate, which closes spaces 55, and is welded to the bottom mouths of tubes 57.
59. Placa base superior, que cierra los espacios 55, y va soldada a las bocas superiores de los tubos 57. 59. Upper base plate, which closes spaces 55, and is welded to the upper mouths of tubes 57.
60. Nivel de la superficie libre del líquido primario en la modalidad de condensador.  60. Level of the free surface of the primary liquid in the condenser mode.
61. Nivel de la superficie libre del líquido primario en la modalidad de generador de vapor.  61. Level of the free surface of the primary liquid in the steam generator mode.
62. Pilares internos del intercambiador 17 para soportar la placa base inferior. 62. Internal pillars of exchanger 17 to support the lower base plate.
63. Somier de soporte general de las estructuras internas del intercambiador 17 63. General support base of the internal structures of the exchanger 17
64. Canal interior de un tubo 57, dentro del cual se produce la ebullición nucleada en el modo de generación de vapor.  64. Inside channel of a tube 57, within which the nucleated boiling occurs in the steam generation mode.
65. Separadores de vapor,  65. Steam separators,
66. Instrumentos de identificación de la superficie libre del líquido en la condensación, que son monitores o medidores de ese nivel.  66. Instruments for identifying the free surface of the liquid in the condensation, which are monitors or meters of that level.
67. Instrumentos de identificación de la superficie libre del líquido en la ebullición, que son monitores o medidores de ese nivel.  67. Instruments for identifying the free surface of the liquid in the boil, which are monitors or meters of that level.
68. Deflector del flujo de la boca del tanque de baja T del secundario, para distribuir uniformemente su movimiento.  68. Deflector of the flow of the mouth of the low T tank of the secondary, to evenly distribute its movement.
69. Deflector del flujo de la boca del tanque de alta T del secundario, para distribuir uniformemente su movimiento. 70. Compresor-circulador para hacer circular el vapor por el sistema de aportación de calor para el sobrecalentamiento, 15. 69. Baffle of the flow of the mouth of the high T tank of the secondary, to distribute its movement evenly. 70. Compressor-circulator for circulating steam through the heat supply system for overheating, 15.
La invención se ha de encuadrar en una planta de generación de vapor para un fin útil, como puede ser la generación de electricidad, que es el caso presentado en la figura 1 , y que reúne todos los elementos para explicar la invención claramente, comenzando por señalar que la invención en sí misma es el sistema de almacenamiento térmico constituido por:  The invention has to be framed in a steam generation plant for a useful purpose, such as the generation of electricity, which is the case presented in Figure 1, and which brings together all the elements to explain the invention clearly, starting with note that the invention itself is the thermal storage system consisting of:
-El ramal 45 que parte del tambor de fases 10, y contiene a la válvula 16. -The branch 45 that starts from the phase drum 10, and contains the valve 16.
-El intercambiador reversible 17, que es propiamente el componente ideado específicamente para esta invención, y que se describe más adelante con el detalle requerido. Su fluido primario es el vapor que le llega para condensarse, o que se genera en su seno cuando opera en el modo de generación. -The reversible exchanger 17, which is properly the component specifically designed for this invention, and which is described below with the required detail. Its primary fluid is the vapor that reaches it to condense, or that is generated within it when it operates in the generation mode.
-El circuito del fluido secundario del intercambiador 17, que está formado por el conducto 20 que atraviesa el intercambiador de la manera que se dirá, y los dos tanques existentes en sus extremos, el de baja T relativa, y el de alta T, que almacenan el fluido secundario.  -The circuit of the secondary fluid of the exchanger 17, which is formed by the conduit 20 that crosses the exchanger in the manner that will be said, and the two existing tanks at its ends, the one of relative low T, and the one of high T, which They store the secondary fluid.
-El ramal 33 de conexión de la boca inferior del intercambiador 17 con el depósito de fluido condensado primario a alta presión.  -The branch 33 connecting the lower mouth of the exchanger 17 with the primary condensate fluid reservoir at high pressure.
-El depósito de fluido condensado primario a alta presión, 27.  -The reservoir of primary condensate fluid at high pressure, 27.
-La válvula 25 y la bomba 26 de descarga del condensado primario de alta presión en el depósito 27.  -The valve 25 and the pump 26 for discharge of the primary high-pressure condensate in the tank 27.
-Circuito de inyección de fluido primario líquido en el intercambiador 17 merced a la bomba 31.  -Injection circuit of liquid primary fluid in the exchanger 17 thanks to the pump 31.
Los elementos mencionados, a excepción del intercambiador reversible The mentioned elements, with the exception of the reversible exchanger
17 son convencionales, pero no es convencional la forma en que se integran en un sistema bidireccional que funciona como almacenamiento de energía térmica y como generador auxiliar de vapor. Mediante la integración que se expone a continuación, junto con el uso prescrito del sistema, se logra que la entalpia del vapor saturado disponible se recoja en dos medios: el propio condensado del fluido primario, que se conserva a alta presión y temperatura; y el fluido secundario calentado, que se almacena en el tanque de alta T. Para ello, el vapor excedente del tambor 10 es condensado prácticamente a la presión que tiene, merced al fluido secundario, y a la transferencia de calor llevada a cabo en el intercambiador. En esa operación, el fluido secundario pasa del tanque de baja temperatura, o tanque frío, al tanque de alta temperatura, o tanque caliente, absorbiendo el calor liberado por el fluido primario en su condensación. Obviamente se pierde exergía en el proceso, pues la temperatura del medio secundario en el tanque caliente estará unos °C por debajo de la temperatura que tenía el vapor. A su vez, aunque el tanque esté muy bien aislado térmicamente, durante el período de almacenamiento perderá más temperatura, lo cual producirá otra pérdida exergética. 17 are conventional, but the way in which they are integrated into a bidirectional system that functions as thermal energy storage and as an auxiliary steam generator is not conventional. Through the integration described below, together with the prescribed use of the system, the enthalpy of the available saturated steam is achieved in two ways: the condensate of the primary fluid itself, which is kept at high pressure and temperature; and the heated secondary fluid, which is stored in the high T tank. To do this, the excess steam of the drum 10 is condensed practically at the pressure that it has, thanks to the secondary fluid, and to the heat transfer carried out in the exchanger. In that operation, the secondary fluid passes from the low temperature tank, or cold tank, to the high temperature tank, or hot tank, absorbing the heat released by the primary fluid in its condensation. Obviously, exergy is lost in the process, since the temperature of the secondary medium in the hot tank will be about ° C below the temperature of the steam. In turn, although the tank is very well thermally insulated, during the storage period it will lose more temperature, which will produce another exergetic loss.
Cuando hay necesidad de producir más vapor en la planta, se activa el modo de generación, y el contenido del tanque caliente, 19, se descarga a través del circuito 20, que tiene como parte principal el secundario del intercambiador 17, para llegar, enfriado, al tanque de almacenamiento de baja T, 18. En ese paso, se transfiere calor al líquido inyectado en el primario del intercambiador 7 desde el depósito de condensado de alta presión, que es donde se recoge el fluido primario en el modo de condensación.  When there is a need to produce more steam in the plant, the generation mode is activated, and the contents of the hot tank, 19, are discharged through the circuit 20, which has as main part the secondary of the exchanger 17, to arrive, cooled , to the low T storage tank, 18. In that step, heat is transferred to the liquid injected into the primary of the exchanger 7 from the high pressure condensate tank, which is where the primary fluid is collected in the condensation mode.
El intercambiador reversible 17 corresponde a una tipología general de carcasa y tubos, pero con una configuración especial, deducida de las funciones que ha de cumplir. En esa configuración son importantes los monitores de nivel, 66 y 67, respectivamente cercanos o ligeramente por debajo de la placa base inferior (58) para el modo de condensación, y cercanos o ligeramente por encima de la placa base superior(59) para el modo de ebullición. Estos medidores de nivel pueden ser del tipo de termopar activo, que miden el valor del coeficiente de película, que es en verdad la variable a vigilar, pues lo que se ha de evitar, particularmente en la ebullición, es que la aparición de una película de vapor seco en la superficie de contacto reduzca mucho el valor de ese coeficiente, y eso perjudique enormemente la transferencia de calor y se pierda eficiencia en el proceso; aunque conviene señalar que en este caso, en el que la aportación de calor procede de un fluido, el secundario, cuya temperatura está dada, no puede ocurrir el fenómeno de "dry out" temido en las vainas del combustible nuclear en los reactores LWR, pues en los reactores hay que extraer la potencia generada en el seno del combustible y la temperatura no está limitada. Habida cuenta de que hay que optimizar el intercambiador, por ser un componente caro, se ha de maximizar su coeficiente global de transferencia, U, cuyo valor viene dado por IT1 = h 1 + (e/kt) + h2 "1 siendo n el coeficiente de película del primario, que es el que se ha de vigilar; h2 es el del secundario, que también se ha de precisar, y que al no comportar cambio de fase, será notoriamente menor que hi; y kt es la conductividad del material de los tubos troncocónicos, y e su espesor. Tanto si se usa aceite como fluido secundario, como si se utiliza una sal fundida, el valor de h2 '\ que es la resistencia térmica de la película del secundario, será el mayor de los tres sumandos del miembro de la derecha en la ecuación anterior, que definía U"1, y por ende U. Eso significa que el valor U será cercano a h2, pero menor que él. A su vez el valor de U ha de hacerse tan alto como se pueda, pues interviene en la determinación del tamaño del intercambiador 17, dado que éste está condicionado al área A de termotransferencia que se define en función de la altura H entre ambas placas base, el número de tubos troncocónicos que hay, N, y los diámetros superior Ds e inferior D¡ de dichos tubos, siendo The reversible exchanger 17 corresponds to a general type of casing and tubes, but with a special configuration, deduced from the functions to be fulfilled. In that configuration the level monitors, 66 and 67, respectively near or slightly below the lower base plate (58) for condensation mode, and near or slightly above the upper base plate (59) for the boiling mode These level meters can be of the active thermocouple type, which measure the value of the film coefficient, which is really the variable to be monitored, since what has to be avoided, particularly in boiling, is that the appearance of a film Dry steam on the contact surface greatly reduces the value of that coefficient, and that greatly impairs heat transfer and efficiency in the process is lost; although it should be noted that in this case, in which the heat input comes from a fluid, the secondary one, whose temperature is given, the "dry out" phenomenon feared in the nuclear fuel pods in the LWR reactors cannot occur, because in the reactors the power generated within the fuel must be extracted and the temperature is not limited. Given that the exchanger must be optimized, as it is an expensive component, its global transfer coefficient, U, whose value is given by IT 1 = h 1 + (e / k t ) + h 2 "1 must be maximized where n is the film coefficient of the primary, which is the one to be monitored; h 2 is that of the secondary one, which also needs to be specified, and that when it does not involve phase change, it will be notoriously smaller than hi; and k t is the conductivity of the material of the conical tubes, and its thickness. Whether oil is used as a secondary fluid, as if a molten salt is used, the value of h 2 ' \ which is the thermal resistance of the secondary film will be the largest of the three addends of the right member in the equation previous, that defined U "1 , and therefore U. That means that the value U will be close to ah 2 , but less than him. In turn, the value of U must be made as high as possible, because it intervenes in the determination of the size of the exchanger 17, since it is conditioned to the heat transfer area A which is defined as a function of the height H between the two base plates, the number of truncated conical tubes, N, and the upper diameters D s and lower D¡ of said tubes, being
A = N HTT (D¡ + Ds)/2 A = N HTT (D¡ + D s ) / 2
Como la potencia térmica a transferir es Q (W), que está definida por la aplicación en cuestión, se cumple  As the thermal power to be transferred is Q (W), which is defined by the application in question, it is met
Q = U A ATim  Q = U A ATim
en la que la diferencia de temperatura logarítmica medía AT|m se define en función de la temperatura de condensación del primario Tc, la del fluido secundario en el tanque de alta T2a y la del fluido secundario en el tanque de baja T2b in which the logarithmic temperature difference measured AT | m is defined as a function of the condensation temperature of the primary T c , that of the secondary fluid in the high T 2a tank and that of the secondary fluid in the low T 2b tank
ΔΤΐπ, = (T2a - T2b)/ln((Tc - T2b)/(TC - T2a)) ΔΤΐπ, = (T 2a - T 2b ) / ln ((T c - T 2b ) / (T C - T 2a ))
y a su vez la potencia térmica Q cumple el balance de energía en el fluido secundario, en función de su caudal másico m2 y el calor específico C2 del fluido secundario and in turn the thermal power Q meets the energy balance in the secondary fluid, depending on its mass flow m 2 and the specific heat C 2 of the secondary fluid
Q = m2 C2 (T2a - T2b) Q = m 2 C 2 (T 2a - T 2b )
Como posteriormente el intercambiador tiene que trabajar como generador de vapor, la temperatura de ebullición del primario Te será menor que T2b , de la misma manera que en el modo de condensación, la temperatura Tc queda por encima de T2a. Ello conduce a que la pérdida de exergía debido al proceso de carga y descarga del almacenamiento se pueda caracterizar porAs the exchanger subsequently has to work as a steam generator, the boiling temperature of the primary T e will be less than T 2b , in the same way as in the condensation mode, the temperature T c is above T 2a . This leads to the loss of exergy due to the process of loading and unloading storage can be characterized by
Tc -Te > T2a - T2b = Q/ (m2 C2) En principio, un alto valor de m2 es esencial para reducir la pérdida de exergía; pero hay que tener en cuenta que ese valor también influye en el tamaño del intercambiador, particularmente en su sección recta, que es la suma de la sección recta de los tubos por los que circula el primario, más la sección recta del secundario S2. Esta última está ligada a m2 por la ecuación en la que intervienen la densidad del secundario p2 y su velocidad v2 T c -T e > T 2a - T 2b = Q / (m 2 C 2 ) In principle, a high value of m 2 is essential to reduce the loss of exergy; but it must be taken into account that this value also influences the size of the exchanger, particularly in its straight section, which is the sum of the straight section of the tubes through which the primary circulates, plus the straight section of the secondary S 2 . The latter is linked to am 2 by the equation in which the density of the secondary p 2 and its velocity v 2 intervene
m2 = S2 p2 v2 m 2 = S 2 p 2 v 2
La opción de impulsar el secundario con una v2 comporta el problema de una fuerte pérdida de carga manométrica, y por ende alta potencia de bombeo, de modo que la realización particular de un intercambiador tendrá que hacerse agregando algunos criterios de optimización, o efectuando un análisis coste beneficio entre coste de inversión y coste de operación, lo cual se escapa del alcance de una patente. Es sin embargo relevante para el diseño tener además en cuenta que el coeficiente de película h2 no es uniforme, sino que depende de las condiciones hidráulicas en cada punto, en particular de la velocidad. Teniendo en cuenta que en las correlaciones de convección para flujo turbulento el valor del número de Nusseit es proporcional a la potencia 0,8 del Reynolds, y que m2 es constante, para un diseño definido, resulta que el valor de h2 es proporcional a Dhe "1'2, donde el Dhe de una sección del tipo que sea es The option of boosting the secondary with a v 2 involves the problem of a strong loss of manometric load, and therefore high pumping power, so that the particular realization of an exchanger will have to be done by adding some optimization criteria, or by performing a Cost-benefit analysis between investment cost and operating cost, which escapes the scope of a patent. It is, however, relevant for the design to take into account that the film coefficient h 2 is not uniform, but depends on the hydraulic conditions at each point, in particular the speed. Given that in convection correlations for turbulent flow the value of the number of Nusseit is proportional to the power 0.8 of the Reynolds, and that m 2 is constant, for a defined design, it turns out that the value of h 2 is proportional D I "1 '2, where D have a section of the type that is is
Dhe = 4 S/Pm D he = 4 S / P m
siendo S la sección de paso, y Pm su perímetro mojado. Con la configuración ideada, a medida que asciende el fluido secundario desde la placa base inferior a la placa base superior, la sección de paso del fluido secundario se va haciendo más pequeña, y su perímetro mojado más grande, por lo cual aumenta el valor de h2, lo cual es beneficioso, pues en el modo de condensador se tiene en la zona superior la menor diferencia de temperatura (Tc - T2a) y por tanto se inhibe por esto último la transferencia de calor, lo cual se compensa con tener más área local de termotransferencia, y mayor valor de h2.. Cuando está en modo de generador de vapor, el efecto de h2 es relativamente secundario, y sin embargo es fundamental dar sección de paso suficiente a las burbujas, cuya fracción de volumen ocupado crece considerablemente al ascender. Ese doble efecto positivo, uno en cada modo, aconseja el montaje tal como se ha ideado en la invención, con tubos troncocónicos de sección recta mayor en su parte alta. Cuestión fundamental es la presión a la que trabaje el fluido primario, P-i , que será notablemente mayor que la del fluido secundario. Por ejemplo, si se pretende que la ebullición sea a 300 °C, la presión ha de estar cerca de las 100 atmósferas (o 10 MPa). Sin embargo, el aceite estará como mucho a 15 bar, y las sales a menos. Para un depósito cilindrico grueso (o una carcasa o barrilete) con una presión P-i , la tensión de aro σ es
Figure imgf000017_0001
S being the passage section, and Pm its perimeter wet. With the configuration devised, as the secondary fluid rises from the lower base plate to the upper base plate, the secondary fluid passage section becomes smaller, and its larger wetted perimeter, whereby the value of h 2 , which is beneficial, since in the condenser mode the lowest temperature difference (T c - T 2a ) is found in the upper zone and therefore heat transfer is inhibited, which is compensated by have more local heat transfer area, and greater value of h 2 .. When in steam generator mode, the effect of h 2 is relatively secondary, and yet it is essential to give sufficient passage section to the bubbles, whose fraction of Busy volume grows considerably when ascending. This double positive effect, one in each mode, advises the assembly as it has been devised in the invention, with truncated conical tubes of greater straight section in its upper part. A fundamental issue is the pressure at which the primary fluid, Pi, works, which will be significantly higher than that of the secondary fluid. For example, if the boiling is intended to be at 300 ° C, the pressure must be close to 100 atmospheres (or 10 MPa). However, the oil will be at most at 15 bar, and the salts at least. For a thick cylindrical tank (or a housing or skipjack) with a pressure Pi, the ring tension σ is
Figure imgf000017_0001
donde r es el cociente entre diámetros exterior e interior del depósito. Para valores altos de temperatura, la σ admisible es menor que la usual a temperatura ambiente, pues el período elástico se acorta y el riesgo de fluencia se acerca, Si Pi es alto, próximo a 10 MPa, por ejemplo, el cociente σ/Ρι admisible es bajo, alrededor de 6. En este caso, el espesor del depósito ha de ser superior al 9% del diámetro interior. Si se acota la pared del depósito a 10 cm de espesor como mucho, el diámetro interior sería aproximadamente de 1 metro. Esto quiere decir que el intercambiador debe ser esbelto, lo cual es una realidad bien conocida. Un caso emblemático es el de los generadores de vapor de ios reactores nucleares PWR, en los cuales la presión está en el entorno de 7 MPa (y no tienen ninguna otra función, ni son reversibles). where r is the ratio between outside and inside diameters of the tank. For high temperature values, the admissible σ is less than usual at room temperature, since the elastic period is shortened and the risk of creep approaches, if Pi is high, close to 10 MPa, for example, the ratio σ / Ρι Allowable is low, around 6. In this case, the thickness of the tank must be greater than 9% of the inside diameter. If the wall of the tank is bounded at a thickness of 10 cm, the inner diameter would be approximately 1 meter. This means that the exchanger must be slender, which is a well known reality. An emblematic case is that of the PWR nuclear reactor steam generators, in which the pressure is around 7 MPa (and they have no other function, nor are they reversible).
Una vez descrita de forma clara la invención, se hace constar que las realizaciones particulares anteriormente descritas son susceptibles de modificaciones de detalle siempre que no alteren el principio fundamental y la esencia de la invención.  Once the invention is clearly described, it is noted that the particular embodiments described above are subject to modifications in detail as long as they do not alter the fundamental principle and essence of the invention.

Claims

REIVINDICACIONES
1 - Almacenamiento de energía térmica mediante condensador-generador de vapor reversible, ubicado en una planta de generación de vapor, caracterizado por que el sistema de almacenamiento térmico comprende:  1 - Thermal energy storage by reversible steam generator-generator, located in a steam generation plant, characterized in that the thermal storage system comprises:
- un tambor de separación (10) del vapor saturado, con tres posibles alternativas de salida, que corresponden a: la recirculación del líquido; al conducto de vapor hacia su aplicación o finalidad; y al conducto de vapor hacia un intercambiador específico (17), de flujo reversible; - a separation drum (10) of the saturated steam, with three possible alternatives of exit, which correspond to: the recirculation of the liquid; to the steam duct towards its application or purpose; and to the steam duct to a specific exchanger (17), of reversible flow;
- dicho intercambiador de calor (17), de flujo reversible tanto en su circuito primario como en el secundario, actuando como condensador cuando el fluido primario tiene una trayectoria descendente, o actuando como generador de vapor cuando el fluido primario va en trayectoria ascendente, teniendo estructuralmente una disposición vertical de carcasa (48, 56, 49) y tubos (57), siendo los tubos troncocónicos, con la boca de menor diámetro abajo, y yendo dichos tubos desde una placa base inferior (58) a una placa base superior (59), y siendo el fluido primario el que circula por dentro de los tubos;- said heat exchanger (17), of reversible flow in both its primary and secondary circuits, acting as a condenser when the primary fluid has a downward path, or acting as a steam generator when the primary fluid goes upward, having structurally a vertical arrangement of carcass (48, 56, 49) and tubes (57), the trunk tubes being conical, with the mouth of smaller diameter below, and said tubes going from a lower base plate (58) to an upper base plate ( 59), and the primary fluid being the one that circulates inside the tubes;
- un subsistema del fluido secundario de dicho intercambiador reversible, consistente en dos tanques de almacenamiento del fluido térmico que se use, seleccionado este fluido entre aceite y sales fundidas, u otra sustancia que sea líquida en el nivel de temperaturas de operación que se fije en cada caso, estando unidos los tanques por un conducto o tubería (20) que atraviesa el intercambiador reversible (17), actuando siempre uno de ellos como tanque de baja temperatura (18), y otro como tanque de alta temperatura (19), yendo el fluido secundario del tanque de baja al de alta cuando el intercambiador actúa como condensador, y yendo el fluido secundario del tanque de alta al de baja cuando el intercambiador actúa como generador de vapor; moviéndose el fluido secundario, seleccionado entre sal fundida, aceite industrial o cualquier otra sustancia estable como líquido a las temperaturas de operación, por la parte exterior (55) de los tubos, entre éstos y la carcasa, siempre de forma predominantemente vertical; - a subsystem of the secondary fluid of said reversible exchanger, consisting of two storage tanks of the thermal fluid that is used, this fluid is selected from oil and molten salts, or another substance that is liquid at the operating temperature level set at each case, the tanks being connected by a conduit or pipe (20) that crosses the reversible exchanger (17), always acting one of them as a low temperature tank (18), and another as a high temperature tank (19), going the secondary fluid from the low to high tank when the exchanger acts as a condenser, and the secondary fluid from the high to low tank when the exchanger acts as a steam generator; the secondary fluid, selected from molten salt, industrial oil or any other substance stable as a liquid at operating temperatures, moving from the outside (55) of the tubes, between them and the housing, always predominantly vertical;
- un conducto (45) de evacuación desde el tambor de separación, a través del circuito primario intercambiador reversible (17), hasta el depósito de condensado a alta presión y alta temperatura (27), estando provisto este conducto en su parte final (33) de una válvula (25) que sólo está abierta cuando el intercambiador actúa como condensador; - an evacuation conduit (45) from the separation drum, through the reversible exchanger primary circuit (17), to the high pressure and high temperature condensate tank (27), this duct being provided at its end (33) with a valve (25) that is only open when the exchanger acts as a condenser;
- un depósito de condensado a alta presión y alta temperatura (27); - a high pressure and high temperature condensate tank (27);
- una bomba de evacuación del condensado (26) en dicho conducto de evacuación, que estimula la tasa de fluido evacuado, y mantiene el nivel de la superficie libre de líquido, en dicho intercambiador (17) reversible, a la altura de la placa base inferior (58) del intercambiador, cuando éste actúa como condensador; - a condensate evacuation pump (26) in said evacuation duct, which stimulates the evacuated fluid rate, and maintains the level of the liquid free surface, in said reversible exchanger (17), at the height of the base plate bottom (58) of the exchanger, when it acts as a condenser;
- un conducto de reposición del vapor, que toma líquido (29) desde el depósito de condensado, lo inyecta en el circuito primario del intercambiador reversible, que actúa en el modo de generador de vapor, y del cual emerge hacia los usos ordinarios del vapor que haya en la planta, estando provisto este conducto de una válvula (30) que sólo está abierta cuando el intercambiador actúa como generador de vapor;  - a vapor replacement conduit, which takes liquid (29) from the condensate tank, injects it into the primary circuit of the reversible exchanger, which acts in the steam generator mode, and from which it emerges towards ordinary steam uses that is in the plant, this duct being provided with a valve (30) that is only open when the exchanger acts as a steam generator;
- una bomba de inyección (31) desde el depósito de condensado (27) hasta el circuito primario del intercambiador reversible (17), que mantiene el nivel de la superficie libre de líquido, en el circuito primario de dicho intercambiador, a la altura de la placa base superior (59) del intercambiador, cuando éste actúa como generador de vapor.  - an injection pump (31) from the condensate tank (27) to the primary circuit of the reversible exchanger (17), which maintains the level of the liquid free surface, in the primary circuit of said exchanger, at the height of the upper base plate (59) of the exchanger, when it acts as a steam generator.
2 - Almacenamiento de energía térmica mediante condensador-generador de vapor reversible, según la reivindicación primera, caracterizado por que cuando en la planta hay excedente de vapor, se abre el circuito de evacuación que desvía parte o todo el vapor producido al circuito primario del intercambiador de calor reversible, 17, que en esos momentos actúa como condensador, y se mantiene la superficie libre del líquido condensado justo a la altura, o algunos centímetros por debajo, de la placa base inferior (58) del intercambiador, lo cual se monitoriza con diversa técnicas, tanto termoeléctricas como electro-ópticas, como visuales, y se ejecuta merced a la bomba (26) que impulsa el condensado desde la boca inferior del intercambiador (47) hasta el depósito a presión del condensado (27); activándose esta bomba a mayor potencia si la superficie libre del líquido sube por encima de la placa base inferior, extrayendo más caudal de líquido, y bajando el nivel de la superficie libre; y reduciendo la potencia de succión en caso contrario, extrayendo menos caudal de líquido cuando la superficie libre desciende de su nivel de consigna, que es la placa base inferior (58). 2 - Thermal energy storage by means of a reversible steam condenser-generator, according to claim one, characterized in that when the plant has a surplus of steam, the evacuation circuit is opened that diverts part or all of the steam produced to the primary circuit of the exchanger of reversible heat, 17, which currently acts as a condenser, and the free surface of the condensed liquid is maintained just at the height, or a few centimeters below, of the bottom base plate (58) of the exchanger, which is monitored with various techniques, both thermoelectric and electro-optical, as well as visual, and are executed thanks to the pump (26) that drives the condensate from the lower mouth of the exchanger (47) to the pressure tank of the condensate (27); This pump is activated at higher power if the free surface of the liquid rises above the lower base plate, extracting more liquid flow, and lowering the level of the free surface; and reducing the power of otherwise, by removing less liquid flow when the free surface falls below its set point, which is the lower base plate (58).
3 - Almacenamiento de energía térmica mediante condensador-generador de vapor reversible, según reivindicación anterior, caracterizado por que durante el funcionamiento del intercambiador (17) como condensador, el calor recuperado es ese cambio de fase es captado por el fluido secundario, que actúa de refrigerante, alcanzando una temperatura muy elevada, en torno a 10 °C por debajo de la temperatura de condensación del fluido primario, y pasa dicho fluido secundario del tanque de baja temperatura, o tanque frío (18), al tanque de alta temperatura, o tanque caliente (19), por accionamiento de la bomba del tanque frío (23), absorbiendo el calor liberado por el fluido primario en su condensación; dejando al fluido primario condensado a presión y temperatura iguales a las que tenía el vapor primario, o algo menores, con una reducción de hasta el 5% en valor relativo a la presión y temperatura del vapor.  3 - Thermal energy storage by reversible steam generator-condenser, according to the preceding claim, characterized in that during the operation of the exchanger (17) as a condenser, the heat recovered is that phase change is captured by the secondary fluid, which acts as a refrigerant, reaching a very high temperature, around 10 ° C below the condensation temperature of the primary fluid, and said secondary fluid passes from the low temperature tank, or cold tank (18), to the high temperature tank, or hot tank (19), by actuating the cold tank pump (23), absorbing the heat released by the primary fluid in its condensation; leaving the primary fluid condensed at pressure and temperature equal to those of the primary steam, or somewhat lower, with a reduction of up to 5% in value relative to the pressure and temperature of the steam.
4 - Almacenamiento de energía térmica mediante condensador-generador de vapor reversible, según la reivindicación primera, caracterizado por que cuando el sistema de almacenamiento ha de proporcionar vapor de fluido primario, a partir de la energía térmica almacenada, el intercambiador (17) actúa de generador de vapor, activándose la bomba de inyección (31) desde el depósito de condensado (27) hasta el circuito primario del intercambiador y el fluido primario circula por su interior de abajo a arriba, siempre por dentro de los tubos troncocónicos (64); y se prescribe el criterio de que la superficie libre de líquido (61) esté por encima de la placa base superior (59), lo cual se monitoriza, por procedimientos termo eléctricos, o electro-ópticos o visuales; y se dispone de dicha bomba de inyección (31) de líquido desde el depósito de condensado a alta presión, a la que se le proporciona mayor potencia de bombeo si se desea subir de nivel la superficie libre de líquido, o lo contrario, si se desea que el nivel baje, para estabilizarse en su referencia, que es la placa base superior; y al mismo tiempo se activa la descarga de fluido secundario desde el tanque caliente (19) hasta el tanque de menor temperatura (18), pasando a través del circuito secundario del intercambiador, activándose la bomba de descarga (21) de dicho tanque caliente.  4 - Thermal energy storage by means of a reversible steam condenser-generator, according to claim 1, characterized in that when the storage system has to provide primary fluid vapor, from the stored thermal energy, the exchanger (17) acts as steam generator, activating the injection pump (31) from the condensate tank (27) to the primary circuit of the exchanger and the primary fluid circulates inside from bottom to top, always inside the conical tubes (64); and the criterion that the liquid-free surface (61) is above the upper base plate (59) is prescribed, which is monitored, by thermoelectric, or electro-optical or visual procedures; and said liquid injection pump (31) is available from the high pressure condensate tank, which is provided with greater pumping power if it is desired to level up the liquid free surface, or otherwise, if you want the level to drop, to stabilize in your reference, which is the upper base plate; and at the same time the discharge of secondary fluid from the hot tank (19) to the lower temperature tank (18) is activated, passing through the secondary circuit of the exchanger, activating the discharge pump (21) of said hot tank.
PCT/ES2012/000155 2011-06-22 2012-06-05 Storage of heat energy using a reversible steam condenser-generator WO2012175763A1 (en)

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Citations (3)

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US4089744A (en) * 1976-11-03 1978-05-16 Exxon Research & Engineering Co. Thermal energy storage by means of reversible heat pumping
EP2157317A2 (en) * 2008-08-19 2010-02-24 ABB Research LTD Thermoelectric energy storage system and method for storing thermoelectric energy
US20110100611A1 (en) * 2008-07-16 2011-05-05 Abb Research Ltd Thermoelectric energy storage system and method for storing thermoelectric energy

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
US4089744A (en) * 1976-11-03 1978-05-16 Exxon Research & Engineering Co. Thermal energy storage by means of reversible heat pumping
US20110100611A1 (en) * 2008-07-16 2011-05-05 Abb Research Ltd Thermoelectric energy storage system and method for storing thermoelectric energy
EP2157317A2 (en) * 2008-08-19 2010-02-24 ABB Research LTD Thermoelectric energy storage system and method for storing thermoelectric energy

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