Patent Application
20100205981
This application claims priority and benefit from Swedish patent application No. 0702649-5, filed Nov. 29, 2007, the entire teachings of which are incorporated herein by reference. Also, the present application has some material in common with the published International patent application No. WO 2007/139476.
The present invention relates to installations and methods for storing and/or transporting energy, also together with a simultaneous purification of a volatile liquid.
Considering the increasing amounts of emission of greenhouse gases it is important to generally change, as much as possible, all energy production so that it does not result in CO2-emission. An apparent method for reducing the emission is to use waste heat from mainly the industry, in particular process industry and similar activities. In Sweden a total use of such energy could more than halve the emissions by supplying heat or cooling to rooms and buildings from energy that is otherwise wasted.
However, the technical and economic challenges are generally known that exist in collecting the large amounts of reject heat produced e.g. in industrial processes. Technically, a device for collecting such energy must be capable of handling high temperatures and a varying supply of energy.
In addition, to use such energy in an economically acceptable way it must be possible to transfer it to a storage medium in which it can be stored with a sufficiently large energy density both per weight unit and volume unit of the storage medium. In for example the published International patent applications WO 00/37864 and WO 2005/054757 chemical heat pumps are described in the accumulators of which, in their charged state, energy can be said to be stored, in some meaning, to thereupon, in the discharging state, be delivered as heating or cooling.
The principle of the function of the chemical heat pump is well known, see for example U.S. Pat. Nos. 5,440,889, 5,056,591, 4,993,239, 4,754,805 and the published International Patent Applications WO 94/21973, WO 00/31206, WO 00/37864 and WO 2005/054757. In a chemical heat pump an active substance is provided that performs the very process of the heat pump and that works together with a volatile medium, the absorbent, which usually is a dipolar liquid, in most cases water. As the working active substance can, according to the prior art, either a solid substance, a liquid substance or a “hybrid substance” be used. By “solid” active substance is meant that the substance all the time, during the whole process and all cycles remains in a solid state, i.e. both with and without a volatile medium absorbed therein. By a “liquid” active substance is meant that the substance all the time, during the whole process and all cycles, remains in a liquid state, i.e. both with and without a volatile medium absorbed therein. By a “hybrid” substance is meant that the active substance during the process in the heat pump is alternating between a solid state and a liquid state.
For a solid active substance, advantages are obtained that include that the cooling temperature in the system in which the heat pump is incorporated remains constant during the whole discharging process and that a relatively large storage capacity can be obtained. A typical value of the storing capacity for a solid substance using water as the absorbent, taken as cooling energy, is about 0.3 kWh/1 substance. Another advantage associated with the use of a solid substance is that no moving components are required in the system. Heat is supplied to or drawn from the substance through a lamellar heat exchanger or a plate heat exchanger that is in a homogeneous contact with the substance. Hence, in the chemical heat pump described in the cited patent application WO 00/31206 no moving components are provided on the process side. The disadvantage associated with a solid substance is the limited power that can be obtained due to the generally low heat conductivity of solid substances. In the same patent application, among other things, a method is described for solving the problem associated with the bad heat conductivity of solid substances and the low power/efficiency resulting therefrom. The method includes that the solid substance is silted up in the sorbate to form a slurry having such a consistency that it can be easily filled around or into a heat exchanger. The amount of sorbate in the slurry should exceed the concentration of sorbate that will later exist in the discharged state of the heat pump. Thereafter, when the substance is charged it obtains a final sintered shape, a so called matrix, which is not dissolved in the normal absorption of sorbate in the operation of the heat pump.
For the use of a liquid substance the advantage of a high power is obtained since the substance can be sprayed over the heat exchanger in both the charging and the discharging processes and hence be efficiently cooled and heated, respectively. The disadvantage associated with a solid substance is that the cooling capacity decreases as a function of the dilution of the absorbent. Actually, it limits strongly the operating interval within which the substance can be used, this in turn reducing the storage capacity, taken as above as cooling energy per litre substance. Most of the liquid substances for use in chemical heat pumps are solutions of strongly hygroscopic inorganic salts in preferably water and similarly water is used as the absorbent. This gives another limitation due the fact that the dissolved substance cannot be allowed to crystallize. Crystallization creates problems in spray nozzles and pumps.
By using a so called hybrid substance several of the advantages associated with solid and liquid systems can be combined, see the International Patent Application WO 00/37864 cited above. The chemical heat pump disclosed in this patent application operates according to a special procedure that can be called the hybrid principle, the hybrid method or the hybrid process. In that process, the substance exists both in a solid and a liquid state during the process, the solid phase being used for storing energy, with as large an energy density as in solid systems whereas the heat exchange to and from the substance is only made in the liquid phase of the substance with as large an efficiency as in common liquid systems. Only the liquid phase is used for heat exchange to the surroundings. A condition thereof is that the solid and liquid phases can be kept to separated during the process. A separation can be obtained by filtering using a separating means of a suitable kind, such as a net or a fitter or in some other way. The liquid phase, often called the “solution”, is pumped and sprayed over a heat exchanger. As in the case of systems using only a solution, i.e. with a substance that all time is liquid, it is important that the pumps, valves and spray nozzles of hybrid systems are not blocked by crystals in the circulation path.
Thus generally, the solid system has in this regard an apparent advantage since it does not require any pumps, valves and spray nozzles.
In
To sum up, the following is true:
Storing thermal energy in thermochemical units containing e.g. silica gel is proposed in the German patent application having publication No. 103 95 583. A heat accumulator in which drying agents such as hydrated salts, ammoniates or zeolites are fixed in a fibrous carrier material and which is used for controlled reception, storing and deliverance of energy is disclosed in the Swedish patent having publication No. 441 457.
It is an object of the invention to provide installations or systems for efficient storing and/or transport of energy.
It is another object of the invention to provide a method of efficiently storing and/or transporting energy together with a simultaneous production of the clean or pure form of a volatile liquid.
In for example the published International patent applications WO 00/37864 and WO 2005/054757 chemical heat pumps are disclosed. They can be used for chemically storing energy in order to thereafter use the stored energy for heating or cooling. By only storing the chemical substance alone it appears that an energy density of 400 kWh/ton can be obtained which should be compared to other methods of storing/transporting energy, e.g. remote heating that gives about 40 kWh/ton. Generally, it is possible to use, using chemical heat pumps, the large amounts of waste heat dissipated that exist e.g. in industrial processes and for example in an economic way transport it to places where the energy has a value of use.
As has been mentioned above, chemical heat pumps working with a solid substance has the disadvantage associated with a very low heat conductivity and hence a low power or efficiency and the advantages of having the ability of working without any moving parts, a high storage capacity and a constant reaction pressure. Chemical heat pumps working with a hybrid substance has the advantages of a high power or efficiency due to the higher heat conductivity and additionally, the fact that they can also work without any moving parts and that they have a high storage capacity and a constant reaction pressure.
In a chemical heat pump working with a hybrid substance, if the solution of the active substance is used to increase the heat conduction between the active substance and the heat exchanger in the accumulator, which can for example be achieved by the fact that the active substance is not submitted to any displacement during the total process in the chemical heat pump, i.e. so that the active substance all the time is stationary or located in a stationary way, a chemical heat pump having a so called “solid” hybrid substance can be obtained. To achieve it, the solution of the active substance can be sucked into and/or be bonded in a passive substance, here called a matrix or a carrier, that generally should be in a good heat conducting contact with the heat exchanger in the accumulator and can be arranged as of one or more bodies which in turn can be closely integrated with each other. That the substance is passive means that it does not cooperate in the absorption and releasing of the volatile medium by the active substance. Thus, the function of the matrix is to maintain the solution of the active substance at the location thereof and thereby increase the heat conduction between the heat exchanger and the active substance when the active substance is changing from its liquid to its solid state in the charging process and from its solid to its liquid state during the discharging process. Thereby the fact that the solution often has a higher heat conducting capability than the solid substance can be exploited. The matrix is formed from a substance that is inert to the process in the heat pump and may generally have an ability of binding the solution phase of the active substance to itself and in same time allow the active substance to interact with the volatile medium. In particular, it may be desirable that the body or the bodies from which the matrix is formed should be efficiently capable of absorbing and/or be capable of binding the solution phase of the active substance in a capillary way. The matrix may include more or less separate particles, such as powders of for example varying granular sizes and comprising grains of varying shapes, fibres having for example varying diameters and varying fibre lengths, and/or a sintered mass having a suitable porosity, that for example does not have to be uniform but can vary within the formed matrix bodies. The size and shape of the particles, i.e. in the special cases grain size, diameter and porosity, and porosity in the case of a solid matrix and the choice of material in the matrix bodies influence in the respective case the storing capacity and power and efficiency of the finished accumulator. In the case where the matrix is applied as a layer to the surface of the heat exchanger, also the thickness of the layer can influence the power or efficiency of the accumulator.
Thus, the processes in the heat pump can be said to be performed with the active substance sucked into a body or wick of fibres or powder which has turned out to result in a high power or efficiency. The power or efficiency has little to do with heat conduction in the body or wick but depends on the reaction in the liquid phase, i.e. among other things the fact that the active substance in its finely divided state changes to a solution that conducts heat better than the finely divided solid material.
The matrix that may be said to be a sucking or absorbing material can be chosen among a plurality of different materials. For example, successful tests have been performed using fabrics of silicon dioxide as a matrix and a matrix including sand and glass powders in different fractions. The heat pump works by the fact that heat is conducted in the liquid phase at the same time as the structure of the matrix is sufficiently permeable to allow transport of the vapour phase of the volatile medium. It is also possible to produce the matrix by sintering a powder or fibres to form a more solid structure.
Such an accumulator, here also called reactor or reactor part and including a matrix, can for example be advantageously used in storing and/or transporting energy according to the discussion above. Accumulators comprising a matrix as described above can allow that large energy quantities are received and that the received energy is stored with a high density compared to comparable substances and thereafter also allow transports which can subject the accumulators including their stored energy to mechanical stress such as mixing movements, vibration and pressure. The accumulator, i.e. the reactor part in which the energy is stored, can thus be stored and transported separately from the condenser and the evaporator, respectively, in the heat pump, and these units can be stationarily arranged in charging or discharging stations, respectively.
The ability of the matrix to suck liquid into it so that the liquid forms the heat carrying medium and the ability thereof of still allowing gas transport through the matrix are equally applicable to the condenser/evaporator unit in a chemical heat pump. When charging the chemical heat pump, gas is being transported through the matrix to be condensed at the surface of the heat exchanger and then be absorbed by the matrix, after which the absorbed liquid increases the heat conduction of the matrix, so that more gas can be cooled, condensed and absorbed. When discharging the chemical heat pump the matrix releases water vapour, this cooling the absorbed volatile liquid that due to the its good heat conductivity transports heat for evaporation from the surface of the heat exchanger through the liquid to the evaporation zone.
Generally, an installation for storing and/or transporting energy can then include a charging station, a discharging station and a storage part. The charging station and the storage part have suitably designed coupling devices to allow that inner spaces existing therein are made to be in communication with one another when the storage part is coupled to the charging station. In the same way the discharging station and the storage part have coupling devices to make inner spaces existing therein be connected to one another when the storage part is coupled to the discharging station. The storage part contains in an inner space an active substance for interaction with a volatile liquid by absorption and desorption thereof.
Advantageously, the storage part can be designed as a reactor part of a chemical heat pump working with a hybrid substance and a matrix according to the description above. It means that the active substance in the reactor part and the volatile liquid are selected in such a way that the volatile liquid can be absorbed by the active substance at a first temperature and be desorbed by the active substance at a second higher temperature. The active substance has at the first temperature a solid state from which the active substance, when absorbing the volatile liquid and the vapour phase thereof immediately partially passes into a liquid state or a solution phase. The active substance has at the second temperature a liquid state or exists in a solution phase from which the active substance, when releasing the volatile liquid, in particular the gas phase thereof; immediately partly passes into its solid state. Furthermore, the reactor art includes a matrix for the active substance so that the active substance, both in its solid state and in its liquid state or solution phase, is held in and/or bonded to the matrix.
The charging station comprises a condenser or similar device such as a suitable pump, in particular a pump of the vacuum pump type. When the storage part is coupled to the charging station and the inner space in the reactor part is in communication with an inner space in the condenser or the similar device, the charging station can from the reactor part receive and/or remove gas phase of the volatile liquid. Thereby, the reactor part is “charged” in the same way as in a chemical heat pump by the active substance being converted to a “charged” state by desorption of the volatile liquid.
The discharging station comprises an evaporator that in an inner space contains a quantity of the volatile liquid in the condensed state thereof. When the storage part is coupled to the discharging station and the inner space in the reactor part is in communication with the inner space in the evaporator, the discharging station can transfer gas phase of the volatile liquid to the reactor part so that the reactor part is “discharged” in the same way as in chemical heat pump by the active substance being converted to a “discharged” state by absorption of the volatile liquid.
According to the description above energy is stored so that it can be transported. This storing of energy means, that in transferring the energy to a storage part it is simultaneously possible to obtain, as a by-product in the transferring operation, pure distilled water in the case where water is used as the volatile liquid. In the corresponding way refilling of water is required on the place where the stored energy is used.
Thus, production of pure water can be made in the way that before “discharge”, i.e. use of the energy in a discharging station, the evaporator is filled with water that can be pure or impure, e.g. salt water or contaminated water. This water is released/evaporated from the evaporator as water vapour, when using the stored energy, whereupon the water vapour is condensed and bonded in the active substance of the reactor part. Later, when the reactor part is being “charged” in a charging station, water is evaporated from the reactor part and is condensed as pure water in the condenser or some similar device. This pure or clean water can be extracted at the discharging station and be used for all purposes that can be conceived for water, e.g. as industrial water or as drinking water. It can be an advantage associated with energy transport according to the description above, as it in the discharging station, i.e. on the place where the energy is used, is possible to use unclean water such as salt water and water contaminated in other ways, which is then returned as clean distilled water in the “charging” operation in a charging station.
Such a production of clean water by purifying impure water, e.g. salt water, can obviously be obtained also in those cases where a hybrid substance and a matrix are not used. The purification of water can be performed without any extra supply of energy and without any costs for the operation. As pure water is more and more becoming a commodity in short supply, the possibility of water production can be an important advantage from the environment point of view, from a health point of view and from an economical point of view. If energy transfer according to the description above is used in a stationary way instead of energy being transported from a charging station to a discharging station located at different geographic places, but is only used for storing energy, to be used later when needed on the same place, clean water can be obtained from unclean water such as salt water and contaminated water. The users of a private home can for example obtain all thermal energy for heating purposes and for conditioned cooling by the procedure that energy from thermal solar radiation receivers as received from the radiation of each day is stored as thermal energy in a storage part. In each cycle including storing energy and delivering energy, in charging the storage part, clean user water can be produced from salt water or water contaminated in other ways. The capacity of the storage part can be adapted proportionally to the energy requirement of the user and thus simultaneously provide for the user's need of clean water. Thus, e.g. the users of a private home can require about 25 000 kWh per year as energy for heating and cooling, which can be adapted by connecting the charging station to a solar radiation collector having a sufficient size. In such an installation about 42 m3 salt water or water contaminated in other ways can be purified each year, covering more than satisfactorily the whole need of the users for clean water.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the methods, processes, instrumentalities and combinations particularly pointed out in the appended claims.
While the novel features of the invention are set forth with particularly in the appended claims, a complete understanding of the invention, both as to organization and content, and of the above and other features thereof may be gained from and the invention will be better appreciated from a consideration of the following detailed description of non-limiting embodiments presented hereinbelow with reference to the accompanying drawings, in which:
a is a schematic of a chemical heat pump according to prior art working according to the hybrid principle,
b is a schematic diagram generally illustrating the principle of a chemical heat pump,
c is a diagram similar to
d is a diagram similar to
a is a schematic similar to
b is a schematic similar to
a, 6b and 6c are cross-sectional detail views of a matrix material placed at a heat exchanger surface,
d is a cross sectional detail view of a matrix material located at a heat exchanger surface from which a flange projects,
a is a schematic similar to
b is a schematic similar to
a is a schematic of components in the installation of
b is a schematic similar to
A system for storing and/or transporting energy will now be described in which the part of a chemical heat pump that contains the “active” substance, is being stored or transported, respectively. In the chemical heat pump schematically illustrated in
According to the hybrid principle the active substance alternates between a solid state and a dissolved state. In order that the chemical heat pump will be capable of working according to the hybrid principle, the active substance must always remain in the reactor 1. A method of achieving it is to restrict the movability of the substance in the solid state thereof using a net 11 as illustrated in
In transport of energy the reactor 1 is physically transported while the active substance is in a suitable active state. During the transport the reactor 1 is physically and in a vacuum tight way separated from the gas channel 4, such as by a shut-off valve, not shown. An evaporator/condenser unit 3′ is suitably provided at the place where one selects to “charge” the reactor 1, i.e. to convert the active substance located therein to a “charged” or “activated” state, e.g. using waste heat from a process industry, see the arrows 31′ in
In storing energy the reactor 1 can in the same way physically and in a vacuum tight way be shut of from the gas channel 4 and be stored on some suitable place, the active substance being in a charged state. When the stored energy is to be used, the reactor 1 is fetched and coupled to the gas channel for a free passage of gaseous sorbate between the reactor and the evaporator/condenser 3. Thus, in this case the evaporator 3″ and the condenser 3′ can be the same unit.
In some cases it can be suitable to arrange one or a plurality of reactor units 1 in an outer holding structure such as a freight container of some kind. The individual reactor units can then be given an elongated shape and for example be designed as tubes that are located parallel to one another. Heat exchange for such parallel tubes can e.g. be arranged through the walls of the tubes so that no inner heat exchange coil is required as in
Now a modified chemical heat pump will be described with reference to
The modified chemical heat pump includes in a conventional way a first container 1, also called accumulator or reactor, containing an active substance 2, herein also called only “substance”. The substance can exothermically absorb and endothermically desorb a sorbate, also called the absorbent, the liquid form of which is called “volatile liquid” herein and which can usually be water. The terms “volatile liquid” and “water” are herein used to denote the liquid form of the sorbate, so that is to be understood that even if only water is mentioned, other liquids can be used. The substance 2 is here illustrated to be held by or carried by or sucked into a matrix or carrier 13 that generally forms or is at least one porous body which has open pores and is made from a suitable inert substance. The matrix can in a typical case consist of a finely divided powder of for example aluminium oxide, applied in a layer having a suitable thickness, for example a relatively thin layer such as a layer having a thickness of 5-10 mm. In this embodiment the matrix in the first container 2 is applied only at the interior surfaces of this container that are located at a first heat exchanger 7, as shown particularly only at the vertical interior surfaces of the first container. The first container 1 is connected to another container 3, also called condenser/evaporator, through a fixed or stationary gas connection 4 having the shape of a pipe that at its ends is connected to the top sides of the containers 1, 3. The second container works as a condenser for condensing gaseous sorbate 6 to form liquid sorbate 5 in an endothermic desorption of the substance 2 in the first container 1 and as an evaporator of liquid sorbate 5 to form gaseous sorbate 6 in an exothermic absorption of sorbate in the substance in the first container. The second container 3 is here illustrated to have half the portion of its interior surface, which is in contact with a second heat exchanger 9, covered with a material 14 that is sucking in a capillary way and half the same interior surface is free. In the embodiment according to the figure it means that half the inner vertical surface of the second container 3 is covered with a material having a capillary sucking function whereas the rest of the interior surface thereof is free. Condensation of gaseous sorbate 6 occurs at the free surface of the heat exchanger 9 in the second container 3, and evaporation occurs from the material 14 that is capillary sucking on the interior surface of the second container.
The various components of the chemical heat pump, also called the system, i.e. the interior spaces in the first and second containers 1, 3 and the gas conduit 4 that are in fluid connection with each other, are entirely gas tight and evacuated from all other gases than the gas 6 participating in the chemical process, also called the volatile medium or absorbent, that usually is water vapour. The active substance 2 in the accumulator 1 is in a direct heat conducting contact with surfaces of the first heat exchanger 7 that in this embodiment is located at the vertical interior surfaces enclosing the accumulator 1, and that thus also can be said to enclose the accumulator, and that can be supplied with heat from or deliver heat to the surroundings through a first liquid flow 8. The liquid 5 in the evaporator/condenser part 3 is in a similar way in a direct heat conducting contact with surfaces of the second heat exchanger 9 that in this embodiment is placed at the vertical interior surfaces of the evaporator/condenser part and hence also can be said to enclose the evaporator/condenser part and to and from which heat can be supplied or transported from or to the surroundings, respectively, through a second liquid flow 11.
The active substance 2 in the chemical heat pump is selected so that it at the temperatures for which the heat pump is intended can operate so that it changes between a solid and a liquid state in the discharging and charging processes of the heat pump. Thus, the reaction in the accumulator 1 occurs between two phases, a solid phase state and a liquid phase state, of the active substance. In the discharging process when the absorbent is absorbed by the substance the first phase is solid whereas the second phase is liquid and then a constant reaction pressure is maintained for the absorbent. The substance will then successively change from a solid to a liquid state at the same time as a constant cooling temperature is obtained. The process continues with a constant reaction pressure until substantially all of the active substance has changed from its solid to its liquid state. In a corresponding way the reaction pressure in the charging process is constant while the substance is changing from its liquid to its solid state.
A normal hybrid substance, see the patent application WO 00/37864 mentioned above, can advantageously be used that is diluted to a desired concentration in the solution of the sorbate and thereafter is sucked into a matrix consisting of an inert powder, i.e. a powder of a material that is not to any substantial extent changed during the operation of the chemical heat pump. Thus, the material should have a solid state during the changing conditions in the heat pump and it should not chemically interact with, i.e. not chemically influence or be affected by, any of the substances or media that change their aggregate states during operation of the heat pump. In tests performed this powder has for example been aluminium oxide and the active substance LiCl. Other possible active substances may be SrBr2, etc., see also the International Patent Application WO 00/37864 mentioned above. The granular size of the powder can here be of importance and also the capability thereof to suck or absorb in a capillary way. To form suitable bodies of the matrix such a powder can first be applied to one or more surfaces of a heat exchanger as a layer having a suitable thickness, for example with a thickness between 5 and 10 mm. In most cases then a net-structure of some kind, not shown, must be applied to the heat exchanger to hold the respective layer in order to form a body from the powder. For example, tests have been performed using layers, having a thickness of 10 mm applied to the outside of pipes, inside pipes and to the bottom of the container. The solution, i.e. the active substance diluted by the volatile medium, also called the sorbate, in its liquid state, is then sucked into the powder in the layers and is allowed to run out of it, until all of the remaining solution is bonded in a capillary way in the powder in the layers. Thereafter, the reactor can be used in the same way as a reactor for a solid substance is used, see e.g. the International Patent Application WO 00/31206 mentioned above.
The matrix together with the substance held therein is in this case not a solid body but a loose mass similar to wet sand in the discharged state of the heat pump. However, in the charged state of the heat pump the matrix is hard. The solution of the active substance has a significantly better heat conducting capability than the substance in the solid state thereof. Heat from the first heat exchanger 7 can then be efficiently transported to or away from the active substance. If for example a matrix consisting of aluminium oxide is filled with a 3 molar LiCl solution, a very rapid and efficient charging of the system is performed down to about a 1 molar solution. Thereafter the power decreases since the active substance now does not any longer contain any solution, i.e. does not exist in any part in a liquid phase or a solution phase. However, there is no problem to drive the process down to the concentration of 0 molar. In the discharging process the process works very well up to a state where the solution is 2.7 à 2.8 molar after which it is retarded. This is so because the matrix has not any longer any permeability to gas when the concentration of 3 molar is reached. In this condition the matrix is full, i.e. the matrix has absorbed as much solution as is substantially possible.
The function and power of hybrid systems using a solution sucked into a matrix is typically significantly better than those of solid systems. However, larger heat exchanger surfaces are required than required for systems using hybrid substances and only a free solution. Tests show that a 2 à 3 times larger heat exchanger area is required to reach, in a hybrid system using a “bonded” solution phase, the same power as in a hybrid system using only a free solution. However, then the power density at the surface in such a system having an increased efficient area of the heat exchanger surface is so small that the heat exchanger does not necessarily have to be directly acting but can advantageously be enlarged. The term directly acting heat exchanger or a directly acting heat exchange between heat exchanger and active substance/solution means that the substance/solution exists at the outer surface of a smooth, simple wall of the heat exchanger while the heat carrying/cooling medium or the fluid in the heat exchanger is circulating at the interior surface of the same wall, i.e. the substance/solution has a substantially direct contact with the heat exchanger medium, through only a relatively thin and flat wall in the heat exchanger. The term heat exchanger or a heat exchange with en enlarged surface means that the substance/fluid exists at a surface of the heat exchanger that has been given an enlarged effective heat exchanging area by for example being corrugated and/or provided with protruding portions of some suitable kind, such as flanges. For a hybrid system using a solution sucked into a matrix it means that also the matrix is located at such a surface of the heat exchanger.
Tests that have been performed at a laboratory scale and then have been recalculated for a full scale have provided data for charging and discharging, respectively, that appear from the diagrams of
The general structure of the matrix is schematically shown in
A material suitable as a matrix material is produced from a powder of Al2O3. The density of the powder grains is 2.8 kg/cm3 and their diameter is 2-4 μm. The powder is applied in layers with a solution of active substance contained therein according to the description above and the dry matrix material in the layers has a bulk density of about 0.46 kg/cm3 which gives an average filling rate or degree of the finished matrix material of 0.45, i.e. almost half the volume is taken by the powder grains. The channels between the powder grains in the produced layers have a diameter of the magnitude of order of 60 μm.
A material suitable as a matrix material is produced by moulding a mixture of 1 (weight) part of Portland cement and 5 (weight) parts of powder of Al2O3 as in Example 1. This material can approximately be considered as “sintered”.
A fibre material suitable as a matrix material is produced from fibres which consist of 54% SiO2 and 47% Al2O3 and have a melting point of about 1700° C. The density of the fibres is 2.56 kg/cm3 and the diameters thereof are 2-4 μm. The fibres are compressed in a wet state to increase their packing density. The bulk density after drying the compressed material is about 0.46 kg/cm3 which gives an average filling ratio of 0.17 of the finished matrix material. The channels between the fibres in the compressed material have diameters of between about 5 and 10 μm.
In the embodiment described above the matrix layer 13 is applied in the simplest possible way, such as to a substantially smooth interior surface of a heat exchanger. Various shapes of heat structures and matrix layers applied thereto can be considered, compare the patent application WO 00/31206 mentioned above. Hereinafter examples on such additional different conceivable configurations of matrix and heat exchangers are given that can be suitable in installations in which the matrix technique as described above is used. Thus, in an ordinary stationary installation the matrix layer can for example be applied to the exterior side of one of more pipes in which a heat exchanger medium or a heat carrying medium is circulating. For example, tests have been performed for pipes having a diameter of 22 mm, around which matrix layers having a thickness of 10 mm have been applied.
It is also possible that all fluid, i.e. typically all the water, in the condenser can be sucked in a capillary way and thereby be completely eliminated as a free liquid in the chemical heat pump, see the installation in
As has been mentioned above, a plurality of reactor vessels 1 can be placed at the sides of each other and be connected to each other to form a storage part, here also called reactor part or reactor package, which can be particularly suited for storing and transporting energy. The storage part can include an outer vessel, a container 41, see
Such a container 41 that can comprise a suitable steel vessel similar to ordinary freight containers for international conveyance of goods, then contains the reactor vessels 1 that can be a number of substantially identical, tubular or plate-shaped units and can be placed in parallel with one another. The individual reactor vessels are interconnected by a collector tube 42 which can be seen as being a prolongation of the gas channel 4 and extends from the reactor vessels to an external coupling part 43. In this coupling part a shut-off valve 44 is connected. Gaseous sorbate such as water vapour can pass in the collector tube and through the gas channel 4, not shown in this figure, when the gas channel is coupled to the coupling part 43, as has been described above when charging and discharging the reactors. The reactor vessels 1 are designed for heat exchange with an external medium that is circulating inside the container 41 and around the individual reactor vessels and that is supplied and removed through two coupling pipes 45, 46 in which shut-off valves 47, 48 are connected. The reactor units are suitably placed in the container 41 as densely as possible considering that a sufficient heat exchange between them and the external medium arranged around the reactor units and circulating in the space in the container around the reactor units, will occur.
Reactor units 1 placed in a container 41 can for example be long steel tubes which are arranged in parallel with one another and can be enamelled and contain active substance that can be bonded to a matrix according to the description above. The connection to the collector tube is suitably located at one end of the steel tubes.
When charging the reactor units 1 in a container 41 the container can be coupled to for example specially configured charging stations located e.g. with industry plants. A container is coupled to a charging station by the three coupling parts 43, 45 and 46. Then, the coupling part 43 of the collector tube 42 does not have to be coupled to a condenser according to the discussion above but can instead be coupled to a simpler device such as vacuum pump. The valves 44, 47 and 48 are opened and surplus heat from a plant such as a process industry in the shape of for example hot water is conducted around the reactor units 1, this bringing the active substance into a “charged” state, i.e. practically, the salt in the matrices in a thermal heat pump according to the description above is being “dried”. The water vapour then formed passes away through the collector tube 42 and the vapour channel (4) and is pumped away from the reactor units. The water vapour can for example in turn work as cooling medium in some of the processes executed in the plant. The water obtained when the water vapour condenses is a distilled liquid and it is thus pure, without any content of salts and contaminations. It can be used in a suitable way, for to example in sensitive processes where distilled water is required or for producing drinking water. After the charging has been finished and the vacuum in the reactor units 1 has been checked, the external heating exchanging medium in the container 41 around the reactor units can be pumped away, the valve 44, 47 and 48 be closed and the container 41 can be transported to a place for storage or to a discharging station.
In the discharging procedure the container 41 can in the same way be coupled to a discharging station which for example is specially designed and where heat or cold is taken from the container. The container is coupled using the three coupling parts 43, 45 and 46. If one wishes to use the energy for cooling, the gas coupling part 43 is under vacuum coupled to an evaporator (3″), which contains some quantity of liquid sorbate and which in addition is in a heat exchanging relationship with a system that one wants to cool. The space in the container 41 around the reactor units 1 is coupled to some object that works as a cooling medium, e.g. a local water stream. Instead, if one wishes to use the energy for heating, the liquid in the space around the reactor units is coupled to the object which one wants to heat, and the evaporator is for heat exchange connected to some form of heating medium that here also can e.g. be a local water stream or water pool. After the discharging operation has been finished, the valves 44, 47 and 48 are closed and the container 41 can be transported back to a charging station.
The evaporator (3″) at the discharging station does not have to contain a matrix but can comprise only a vacuum tight vessel with the condensed sorbate contained therein, a quite conventional heat exchanger and a pump sprinkling water over the heat exchanger. As the process in this station runs in only direction, i.e. sorbate is transported as vapour from the evaporator to the reactor 1, the evaporator does not have to be equally well protected against corrosion as in the embodiments of
Thus, clean water can be obtained as a by-product when transferring energy using an energy storage device such as the storage part formed by one or more reactor vessels 1 according to the description above and suitable charging and discharging stations. Production of water could then be performed by filling before discharging, i.e. before the delivery of energy, the evaporator (3) in the discharging station with unclean water such as salt water or other contaminated water. This water is released/evaporates from the evaporator during the delivery of energy as pure water vapour, whereupon the vapour is condensed and bonded in the active substance of the reactor 1. Later, when the reactor is charged in a discharging station, water is released as water vapour from the reactor and is condensed in the condenser (3) as clean water. This clean water can be extracted and used for all purposes conceivable for water, e.g. as industry water or as drinking water. Practically, such water can be produced in two ways, either with an energy storage part, in which energy is stored on one place to then be used on another place, i.e. for transport of energy, or in which the energy is stored on the same place where it later is to be used:
1. Energy is stored in the energy storage device on one place to be thereupon transported and used on another place. Clean water can then if desired be delivered to the place where the storing of energy is executed, i.e. the producer of energy supplies energy and obtains clean water. The receiver of energy at the other place provides and fills the system with water that must not be clean but can be salt water or contaminated water.
2. Another process of obtaining clean water can include that the storing of energy and the use of energy are made on the same place, i.e. stationarily, e.g. where houses or commercial buildings need both of them. A typical such installation can take its energy from solar radiation collectors, the energy of which is stored until the energy must be used, and takes its water that is to be purified from the sea or from some weakly contaminated water source. To perform production of water one fills e.g. contaminated water in an evaporator intended for this purpose before delivering thermal energy, both for heating and cooling, from the energy storage part. The condenser and evaporator are then separate devices that are coupled to the storage part, so that the condenser is used in the charging process and the evaporator in the discharging process, in order not to contaminate a common condenser/evaporator 3 according to e.g.
The procedure of charging a container 105 containing one or more reactor units will now be described with reference to
In charging station 50 the container 41 is connected to an industry unit or factory 51 with its coupling pipes 45, 46 including valves 47, 48 coupled to coupling devices 52, 53 including shut-off valves 54, 55. The container is also at the interface 33 connected to a condenser 3′ or similar device having its gas coupling pipe 43 including the valve 44 coupled to a coupling device 57 including a shut-off valve 58. The industry unit or factory 51 supplies energy, see the arrow 59, as heat, such as waste heat, to the reactor unit 1 in the container 41. The heat energy is transferred in a hydraulic system, e.g. using water, or in a pneumatic system, e.g. using air, the heat exchanging or heat carrying medium here being called energy carrier. Energy carrier having a lower temperature is fed back, see the arrow 60, to the industry unit or the factory to collect energy as waste heat. At the same time the condenser 3′ can be cooled, see the arrows 61, 62, by a source indicated at 63, that has a constant temperature which is lower than the temperature of the energy when it leaves the industry or the factory 51. The condenser could also here in the simplest case be a vacuum pump.
Due to the ΔT, the definition of which is described in the above mentioned published patent application WO 00/37864, that exists between the substance in the reactor unit 1 and the condenser 3′ a pressure difference is formed between them, the pressure difference causing that water that is absorbed in the active substance in the reactor is vapourized and quickly moves, see the arrow 64, to the condenser, where the water vapour is condensed.
After the charging operation has been finished, i.e. after a sufficient amount of water has entered the condenser 3′, the space around the reactor unit 1 in the container can be emptied from energy carrier, all valves be closed and the container 41 be disconnected from the charging station 50 at the physical interfaces 33, 65 and 66. Thereafter, it can be stored or conveyed to another place.
The procedure of discharging a container 41 containing one or more charged reactor units 1 will now be described with reference to
The container 41 together with its charged reactor units is connected a discharging station 70, which in a special case such as for storing energy can be the same as the charging station 50, but in other cases is separate therefrom and can be located for example at a large geographical distance from the charging station. The container is coupled at the three physical interfaces 33, 64, 65. The coupling pipes 45, 46 including valves 47, 48 are coupled to coupling devices 71, 72 including shut-off valves 73, 74 in the discharging station. The container is also connected to an evaporator 3″ with its gas coupling pipe 43 including a valve 44 coupled to a coupling device 75 including a shut-off valve 76. After all coupling devices having been connected, all these valves 47, 48, 73, 74, 44, 76 are opened to start the discharging process.
Due to the ΔT that exists between the inner spaces of the reactor unit 1 and the evaporator 3″ a pressure difference is formed between them, the pressure difference causing that the water in the evaporator starts boiling and the water vapour formed quickly moves, see the arrow 77, to the reactor unit in the container 41, where the water condenses in the salt of the reactor unit.
In the case where one wishes to use the energy stored in the reactor as heat, e.g. in a village or town, the space in the container 41 around the reactor unit 1 is connected to the district heating system of the village or town, this being in
In the case where one instead wishes to use the energy stored in the reactor unit 1 in the container 41 for cooling purposes, the heat exchanging surfaces of the evaporator 3″ are connected to the cooling system of the village or town, symbolically indicated as the reservoir 92 in
After all stored energy has been collected from the reactor unit 1 in the container 41, the valves around the interfaces 33, 65 and 66 are closed. The discharged reactor can thereupon be conveyed to a charging station 50 and be connected thereto.
In
On place A for example roughly filtered water is filled to the stationary evaporator 3″ from a filling vessel 111 by opening a valve 113, see
Thereupon, a discharged reactor part 1 (at H in
In
While specific embodiments of the invention have been illustrated and described herein, it is realized that numerous other embodiments may be envisaged and that numerous additional advantages, modifications and changes will readily occur to those skilled in the art without departing from the spirit and scope of the invention. Therefore, the invention in its broader aspects is not limited to the specific details, representative devices and illustrated examples shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within a true spirit and scope of the invention. Numerous other embodiments may be envisaged without departing from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 070264905 | Nov 2007 | SE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/SE08/00676 | 11/28/2008 | WO | 00 | 4/28/2010 |
