WO2004010057A1

WO2004010057A1 - Storage vessel for thermal storage of energy in a liquid, apparatus and method for feeding liquid to a storage vessel

Info

Publication number: WO2004010057A1
Application number: PCT/SE2003/001227
Authority: WO
Inventors: Klaus Lorenz
Original assignee: Klaus Lorenz
Priority date: 2002-07-22
Filing date: 2003-07-18
Publication date: 2004-01-29
Also published as: SE523488C2; SE0202314L; AU2003246235A1; SE0202314D0

Abstract

For the purpose of feeding heated liquid (UV) into a storage vessel (100) to achieve efficient thermal storage of energy in liquid contained in the vessel, and to do so with minimal exergy loss, the storage vessel is equipped with an input device (111) through which supplied heated liquid is introduced into the vessel through stratification channels (116, 117, 118) in such a way that minimal turbulence arises and that optimal stratification is maintained in the vessel. This is achieved by means of an input device whose stratification channels are formed in a filler material, and by the fact that the filler material consists of separate bodies (113) that form the stratification channels between themselves and that engage on one another with a substantially point contact between them. In this way a compact energy charger may be efficiently and easily constructed having stratification channels that are distributed and directed so that the liquid is supplied to the vessel in an advantageous way.

Description

TITLE: STORAGE VESSEL FOR THERMAL STORAGE OF ENERGZIN A LIQUID,

APPARATUS AND METHOD FOR FEEDING LIQUID TO A STORAGE VESSEL.

TECHNICAL FIELD

This invention relates in general to thermal energy storage and in particular concerns storage of heat or cooling energy in a liquid contained in a storage vessel such as an accumulator tank.

BACKGROUND

In systems for heating dwellings and other premises or for the supply of hot water, it is normal to use a liquid to distribute the heat energy produced in a heating boiler or similar. To make the heating system more efficient it is necessary for the energy produced by the boiler to be stored in an optimal way to allow discharge when required. In this way, it is possible to run a boiler in the most advantageous way without being governed by acute heat requirements. Thus, an electrical heating element can be connected when the electricity is cheapest and/or a wood fired boiler or other boiler for bio-fuel can be run in an optimal way for the best combustion and reduced emissions. Regarding solar energy, storage of the heated liquid is a requirement to allow functional running with the possibility of demand controlled energy discharge.

The thermal energy storage discussed above, traditionally takes place in an accumulator tank 1 (see attached fig 1 A) where heated liquid is stored to enable it to be drawn off later when required. Basically, liquid has been fed into the tank at a fixed inlet level and it has been relied on that the supplied liquid would rise in the tank when its temperature was higher than that of the liquid in the tank at the inlet point and that the supplied liquid would sink in the tank when its temperature was lower than that of the liquid in the tank at the fixed inlet point. However, it is well known that the efficiency of the system can be considerably improved by providing for and maintaining stratification in the accumulator tank, i.e. by ensuring that the hottest liquid VV is found in the top of the tank and the coldest liquid KV is found in the bottom of the tank. Traditionally, attempts have been made to achieve this by supplying the heated liquid UV into the hottest layer at the top of the tank while the coldest liquid in the layer furthest down in the tank is returned RV for renewed heating.

It is also well known that the supply and also the discharge of liquid in general shall be at a low velocity to reduce turbulence in the tank. Otherwise, such turbulence results in deterioration of the stratification and, as a result, there are energy losses from the liquid in the different layers being mixed. However, mere reduction of the input flow does not give an optimal reduction of the detrimental turbulence. This is partly because when introduced into the tank the supplied liquid still has too much kinetic energy, and partly because, in practice, the liquid in the tank is not divided into two clearly defined hot and cold layers. Instead it can be said that between the top and the bottom of the tank, i.e. between the uppermost hottest layer and the lowest coldest layer there is a "transition layer" where the temperature of the stored liquid is evened out between the hot and the cold layers without any real boundary. Expressed otherwise, there are a number of diffuse intermediary layers of liquid at different temperatures throughout the height of the tank. If heated liquid at a certain temperature is supplied at the top of the tank, the temperature difference between the supplied liquid and the stored liquid will inevitably cause a certain amount of turbulence even if the feed rate is minimised, leading to undesirable mixing of the supplied liquid and the liquid in the tank. Such a mixing resulting in a lowering of the. temperature means that exergy content is lost which can be explained as a loss of "usefulness" of the energy that was added on heating the liquid. Exergy is an accepted definition that in general' refers to the "quality" of energy. Specifically the conception exergy refers to a deviation from a thermodynamic state of equilibrium and it has been introduced to be able to measure the difference in quality between different sorts of energy.

hi EP 0384 432 is described an accumulator tank 10 that with the object of reducing the discussed problems is provided with what can be described as an "energy charger" 11. This is illustrated schematically in the attached fig IB. The energy charger 11 consists, in principle, of a tube 12 that is positioned within the tank and that receives the heated liquid UV that is to be supplied into the tank. There are a number of outlet openings 13 distributed along the length of the tube 12, each being provided with an easily moveable flap non-return valve to feed the heated liquid into the tank at the right level, i.e. at a level where the temperature of the supplied liquid substantially corresponds to the temperature of the liquid in the tank. With the aim of clarification, this is illustrated in the attached fig. IB by six different temperature levels or layers A-F at different heights above the bottom of the tank. Apart from this solution only giving a relatively rough distribution of levels of the liquid and no great reduction of its kinetic energy, it is regarded as a disadvantage that the energy charger is permanently mounted in the tank and is therefore difficult of access for service. In a variation of the above described solution shown in DE 4 443 715, placement of an internal heat exchanger 14 in the energy charger 11^', as illustrated schematically in fig. IC, is a well known method. The tank liquid heated by the heat exchanger rises in the charger's centre pipe 12' and goes out through the easily moveable flap non-return valves at the different levels in the same way as previously described. This construction has, on the whole, the same disadvantages as the previously described type.

DESCRIPTION OF THE INVENTION

The invention eliminates the above problems in an efficient and appropriate way.

A general object of the invention is to find a solution to the problem of effectively "charging" a storage vessel for thermal energy storage in a liquid.

To be more precise, a basic object of the invention is to find a simple and appropriate way of supplying heated liquid to a storage vessel with the least possible loss of exergy, in order to achieve the efficient thermal energy storage in the liquid contained in the tank. Through the invention, this is achieved by a storage tank being equipped with an input device that can also be called an "energy charger" and through which the supplied heated liquid is fed into the vessel in an efficient way with minimal turbulence and so that optimal stratification is maintained in the vessel. More specifically, this is achieved by the energy charger's stratification channels being formed in a filler material in the input device and by the filler material consisting of separate bodies which between them form stratification channels and which bear on each other substantially with a point contact between them. With such a design, a compact energy charger may be efficiently and easily constructed, having stratification channels that are distributed and directed so that the liquid is fed into the vessel in a favourable way.

In one embodiment of the invention the energy charger is provided with a large number of small channels that are directed in different mutual directions, that are connected to one another, and that all communicate, directly or indirectly, with a heated liquid inlet and also, essentially without resistance, with the interior of the storage vessel. In this way, it is possible to considerably reduce the kinetic energy of the heated supplied liquid and to feed liquid into the vessel at a level therein that is adapted to the temperature relationship between the liquid in the tank and the supplied liquid.

In other practical embodiments of the invention, the energy charger's bodies are in alternative designs completely individual or connected with one another in the points of contact therebetween.

In yet another embodiment of the mvention, the bodies have a generally spherical shape that, in particular in a design having bodies of an equal size, in an easy way ensures that the liquid drains equally easily in all directions through the energy charger.

In an alternative embodiment, the bodies are of at least two different sizes and are positioned with the largest size closest to a liquid inlet to the input device, whereas the bodies with the smallest size are positioned closest to the interior of the storage tank. In this manner, the supply of the liquid to the storage vessel can be controlled so that a successive reduction of its kinetic energy is achieved through its velocity gradually being reduced more and more.

In a practical embodiment of the invention, the input device is placed on the outside of an exterior wall of the vessel. In this way, with the input device placed outside the storage vessel, service and maintenance work is facilitated.

In another practical embodiment of the invention the input device presents a liquid-impermeable outer casing that contains the separate bodies and that presents an open side towards the inside of the storage vessel and that the input device at the casing's open side is equipped with a. liquid-permeable wall. In this way, good flow into the interior of the storage vessel is ensured and at the same time, the bodies are held securely in place.

Another object of the invention is to provide simple and appropriate equipment for efficient charging of a storage vessel for thermal storage of energy.

In another aspect of the invention, an input device or energy charger is therefore proposed for mounting on a storage vessel for thermal storage of energy, which, in accordance with the invention's basic principles, has stratification channels that are formed in a filler material composed of separate bodies.

A further object of the invention is to provide a simple and appropriate method of "charging" a storage vessel for thermal energy storage by a supply of heated liquid to the storage vessel with a minimum loss of exergy.

In a further aspect of the invention, a way of supplying the heated liquid is therefore proposed, by which the liquid, before entering the storage tank, is divided up into sub-streams that are led through stratification channels formed in a filler material composed of separate bodies. The sub- streams are led in different directions in the different channels so that the supplied liquid is drained substantially equally well in the different directions. Thereby is secured that the supply of liquid to the storage vessel takes place at a low velocity and thereby with low momentum and that the supply is carried out at different levels in the storage vessel, corresponding to the temperature of the supphed liquid and thus that a temperature stratification is maintained in the liquid in the storage vessel.

These and other objects of the invention are achieved by the invention as it is defined in the attached patent claims and in particular preferred embodiment of the different aspects of the invention are specified in the respective dependant subclaims.

Further objects, features and advantages of the invention, as well as further embodiment thereof are clarified by the dependent patent claims as well as in the following description of exemplifying embodiment.

DESCRIPTION OF THE FIGURES

The invention is described further in detail below in connection with the attached drawings, of which:

Fig 1A-C shows schematic examples of earlier used known storage vessels for thermal storage of energy; ig 2A shows the principles of the present invention in a schematic, partially sectioned side view of a storage vessel with energy charger according to the invention; ig 2B is an illustration corresponding to fig 2A of a first embodiment of a storage vessel with an energy charger according to the invention;

Fig 3 A is a detailed view in section of part of the energy charger of fig 2B, illustrating the process by the supply of liquid at a first temperature;

Fig 3B is a detailed view corresponding to fig 3 A, illustrating the process by the supply of liquid at a second temperature;

Fig 4 is a partial illustration of second embodiment of an accumulator tank with the energy charger according to the invention;

Fig 5A is a diagram showing the temperature distribution with time in a storage vessel by the supply of heated liquid without the use of an energy charger;

Fig 5B is a diagram corresponding to fig 5A showing the temperature distribution with time in a storage vessel by the supply of heated liquid with the use of the energy charger according to the invention; and

Fig 6 is a schematic illustration of a third embodiment of an accumulator tank with an energy charger according to the invention.

DESCRIPTION OF EMBODIMENTS

With reference to, in the first place, figures 2A-B and 3A-B the basic principles of the invention will now be described with the help of a first embodiment shown in these figures, and, at the same time, the differences to the known technology exemplified in fig 1 A-C will be clarified.

h Fig. 2A, a storage vessel 100 is shown schematically. It is filled with a liquid in which thermal energy is stored stratified corresponding to the temperature of the liquid, as is illustrated by the marked liquid layers A-F with the aim of clarification, hi this discussed application, where heat energy is stored in the vessel 100, heated liquid UV, i.e. liquid containing additional thermal energy, will therefore be supplied to the storage vessel 100. Liquid with the highest temperature will be stored in the uppermost layer A and liquid with the lowest temperature will be found in the lowest layer F. In the illustration, the liquid is shown in defined layers A-F but it must be emphasised that in practice there is normally no clear boundary between all the different layers but rather an mdefinite transition. In connection to the upper part of the storage vessel 100, in the hottest uppermost layer A, operating liquid is drawn off, for example in the form of hot water or water to the radiators, and in the bottom of the vessel, return liquid RV is led back from the coldest layer F for renewed heating. The return liquid RV is preferably reheated in a heat exchanger 114 by a liquid PV that has been heated for example in a heating boiler or in a solar collector. So far, the thermal storage of energy takes place in a traditional way.

According to the invention, the liquid UV heated in the heat exchanger 114 is supplied to the storage vessel 100 through an input device 111 that may preferably be called an "energy charger". The principles of the function of the energy charger 111 will now be described in connection with an embodiment that is very schematically illustrated in fig 2A. Here the energy charger 111 is attached to an outer wall 101 of the storage vessel 100 and consists of a liquid-impermeable outer casing 112 that has an inlet 119 for heated liquid and that widens out in a general funnel shape from the inlet 119 towards the storage vessel 100. By placing the input device 111 on the outside of the outer wall 101 of the vessel 100, i.e. with both this and the heat exchanger 114 placed outside the storage vessel 100, service and maintenance work is facilitated to a great extent.

The energy charger 111 with an open side thereof is in substantially completely open communi- cation with the inside of the storage vessel so that the heated liquid UV that has found its way, in principle without resistance, through the energy charger 111 can be transferred to the inside of the storage vessel. This open communication or open side extends over a main part of the height of the storage vessel 100, from the uppermost hottest layer A downwards; in the illustrated embodiment, more precisely, from the hottest layer A down to the next lowest or next coldest layer E. The exact height of the energy charger 111 can however vary in different practical designs. The width of the energy charger 100 in a direction perpendicular to the plane of the drawing in fig 2A is not further specified here, but can likewise be varied for different applications. The inside of the energy charger 111 contains a multitude of small stratification channels (not shown in detail in fig 2A) that divide the supplied heated liquid UV into sub-streams that are illustrated very schematically in fig 2A by the drawn arrows. These stratification channels are directed in mutually different directions, are in communication with one another and with the liquid inlet 119 as well the inside of the storage vessel 100. Thus, they serve to divide the heated liquid UV entering through the liquid inlet 199 into the differently directed sub-streams 115. By the division of the liquid UV into these small sub-streams 115 the liquid will drain equally well in all directions and will be conducted a long way through the channels before it finds its way to the inside of the storage vessel 100 at a level or a layer A-E that has substantially the same temperature as the sub-stream in question 115. As the sub-streams 115 of the supplied heated liquid UV are conducted a long way in the stratification channels before entering the vessel 100, the liquid will flow at a low speed, i.e. with appreciably reduced kinetic energy or with low momentum, to be stratified in the tank in the layer of the vessel liquid A-E that has the same temperature as the supplied liquid. This, in combination with the fact that the sub-streams through the multitude of channels and the substantially open communication between the energy charger 111 and the vessel 100 can be introduced into the inside of the vessel at exactly the right level, adapted to the temperature relationship between the liquid in the tank and the supplied liquid means that the heated liquid UV can be supplied to the vessel with a minimum of turbulence and a minimum of mixing of volumes of liquid at different temperatures.

Turbulence leads to mixing and counteracts stable temperature stratification that would, for example, increase solar heating yield. By avoiding turbulence, lower liquid temperature is therefore obtained in the lower part of the vessel 100, which normally contributes to optimising the use of a heat source and particularly improves the yield of a solar collector. At the same time, this elimination of turbulence results in a high useful temperature in the upper part of the vessel, which means that stored heat energy, such as solar heat, lasts longer than in a less well-stratified system. The improved stratification that is achieved through the invention is illustrated in fig. 5 A and 5B.

In particular, the diagram in fig. 5A shows an example of the temperature distribution with time in a heating test in a vessel of the traditional type (i.e. similar to the storage vessel 1 as in fig.lA) without any form of energy charger. In the diagram, the curve Tuv shows the temperature of the heated supplied liquid UV and the curves T_A to T_F show the temperature distribution with time in layers A-F corresponding to the illustrations in fig. 2A and 2B.

In fig. 5 A, the gentle slope of the temperature curves T_A to T_F shows how the liquid UV that is supplied without an energy charger, is mixed in the vessel so that very inefficient stratification is achieved. Fig. 5B shows an example of the temperature distribution with time in a heating test with the energy charger proposed according to the invention. The considerably steeper slope of the curves T_A to T_F shows that the stratification is much more pronounced and is maintained better by means of the energy charger. The designs of earlier energy chargers shown in fig. IB and IC give a somewhat better temperature distribution with time and better stratification than in fig 5A, but still give rise to turbulence and more insensitive division into layers by the supply of the heated liquid. Consequently, these do not provide nothing like the advantageous effects that are shown in fig. 5B.

Fig. 2B and figs. 3A-3B show an embodiment of the storage vessel 100 according to the invention where the small stratification channels in the energy charger 111 are formed in a filler material contained by the liquid-impermeable outer casing 112. Here the filler material is composed of separate spherical, i.e. globular bodies or balls 113. The bodies 113 are of uniform size and bear on one another through points of contact P, whereby the small stratification channels or sections of these 116, 117, 118 are formed between the adjacent bodies 113 and between these and the casing, respectively, and are directed in mutually different directions. The channels and consequently the sub-streams 115 of the liquid that is led in these are given an almost arbitrary course that favours the flow of the liquid in all directions. As the stratification channels furthermore are in direct or indirect communication with the liquid inlet 119 of the input device and with the liquid A-F in the inside of the storage vessel 100, respectively, the supplied liquid UV will therefore find its way to the right level in the storage vessel at the same time as its velocity is gradually reduced.

With the energy charger's 111 stratification channels formed in a filler material 113 in the input device it will be possible in practice to provide a compact energy charger containing a very large number of channels that are, in principle, directed in all directions. In the shown embodiment where the energy charger 111 filler material consists of a large number of separate bodies 113 that form stratification channels 116, 117, 118 between them, the large number of small stratification channels can be formed efficiently and easily. By designing the bodies with a general spherical or globular shape, in particular by the design with uniform size of the bodies, it is easy to ensure that the liquid drains or flows equally well in all directions through the energy charger. The bodies 113 shall take up as little as possible of the energy of the supplied liquid UV and accordingly they shall basically consist of a low density material.

In this case, the interior of the energy charger 111 is not completely open towards the storage vessel 100 as there is a liquid-permeable partition wall 120 in the transition zone between these. The partition wall only serves to retain the bodies 113 and shall offer as little flow resistance as possible. For example, it may consist of a coarse-meshed net. By positioning this open side so that it faces the interior of the storage vessel 100 and by the fact that the energy charger is equipped with the liquid-permeable wall 120 at the open side of the casing, good flow is ensured into the storage vessel's interior at the same time as the bodies are held securely in place.

Fig. 3 A and 3B are detailed views at an enlarged scale of the energy charger 111 according to fig 2B and illustrate schematically the principles of the invention regarding the path of the heated liquid UV between the inlet 119 and the interior of the storage vessel 100. In fig. 3 A, a case is illustrated where the temperature of the supplied liquid UV is lower than the temperature of the liquid A in the upper layer of the vessel. The figure illustrates how the heated liquid UV after the inlet 119 is divided up into several sub-streams 115 in the channels 116, 117, 118 that are formed between the bodies 113. In this way the sub-streams 115 of the supplied liquid UV find their way to the "correct" level, shown here in the transition zone between layers B and C, between the hottest A and the coldest F layers in the vessel. On their way from the inlet 199 to the vessel 100, the sub-streams 115 will therefore be led a long way in the channels 116, 117, 118 so that the velocity of the liquid is reduced and the generated turbulence with the ensuing mixing is minimised.

In fig. 3B, another situation is illustrated where the supplied liquid UV has a temperature that is similar to or higher than the temperature of the uppermost layer A. Here the liquid UV will be divided into sub-streams 115 that seek their way towards the uppermost layer A of the vessel 100 in the channels 116, 117, 118 formed between the bodies 113 that are provided near an upper wall 112A of the energy charger 111 casing 112. In this situation the same advantageous reduction of the velocity of the inflowing liquid UV in the channels 116, 117, 118 is achieved and at the same time the liquid finds its way to the correct level for this situation in the vessel 100. In this situation, a relatively clear boundary layer is normally formed between the incoming hot water UV in the vessel's top layer A and the colder water in the vessel. Even if this is not shown in the figures, liquid from the vessel 100 will be found in the energy charger 111. At an initial stage, when no heated liquid UV is supplied to the energy charger 111, this liquid from the vessel 100 will be present in the energy charger, stratified corresponding to the different layers. This means that the energy charger can also be characterized as a "pre mixing chamber" in which the above discussed desired reduction of the velocity of the incoming liquid UV is achieved.

In fig 4 is shown a partial view of a storage vessel 100 being provided with an alternative embodiment of an energy charger 211 according to the invention. In this embodiment, the filler material of the energy charger 211 consists of separate bodies 113 A, 113B and 113C of different size. More specifically, there are three sizes of bodies here and the bodies are provided in the casing 112 so that the bodies 113C of the largest size are closest to the liquid inlet 119 of the energy charger 211. The bodies 113 A of the smallest size are provided closest to the interior of the storage vessel 100 while the mid-sized bodies 113B are provided in an area between the largest and the smallest bodies. In this way, a successive reduction of the kinetic energy of the supplied liquid is achieved by gradually reducing its velocity more and more. By using groups of bodies of different size in this way, and by varying the number of groups as well as the mutual relationship of the bodies with regard to size and the mutual positioning of the groups, the path of the liquid UV through the energy charger may be controlled in accordance with different desires.

In the embodiments of the invention shown and described up to now, the energy charger has been shown attached to the outside of the vessel in all cases. Even if such a design is in most cases preferable for service and maintenance reasons, the energy charger may also be mounted in another way with essentially maintained function. This possibility is illustrated in fig. 6, which schematically shows an embodiment where the energy charger 311 by means of the indicated fixing devices, 330, 331 is supported inside the storage vessel 300. It must be emphasised that in practical designs the dimensions of the energy charger 311 as well as its positioning and fixing in the storage vessel 300 may depart from that which for exemplifying purposes, is shown in fig.6. In addition, in this case it is suitable that the heat exchanger (not shown in fig.6) is provided outside the storage vessel 300, as in the embodiment of fig 2A, in order to facilitate service and maintenance.

Furthermore, in some cases, it may be desirable to allow the possibility of accessing also the energy charger for service or repair, and this may preferably be achieved by providing a removable hatch 240, shown in fig. 6, in the bottom of the vessel 300. A corresponding hatch may also be arranged at one of the sides of the vessel or at its upper part and for simple dismounting and removal of the energy charger, this may even be supported by the hatch.

Even if the invention has been described above with reference to the specific embodiments shown on the drawings, it must be emphasised that it also covers other variations employing the basic principles of the invention. Therefore, within the framework of the invention it is likewise possible to form the stratification channels in other filler materials than the shown separate bodies or to use such illustrated separate bodies having other shapes than the spherical ones shown, hi its broadest scope the invention covers also the use of such variations that are covered by the enclosed patent claims. It must furthermore be emphasised that the expression "separate" does not only include fully individual bodies that loosely engage one another, but also separate bodies that have been bonded or adhered to one another at the contact points. In a variation of the invention, not shown in detail, the filler material may therefore be formed of separate bodies that are placed in a casing, loosely engaging one another. Then a binding agent with relatively low viscosity, for example a loose or low viscosity cement and water mix, is supplied and is allowed to fill the spaces between the bodies. After this, the binding agent is drawn off before it sets or hardens so that binding agent remains on the surfaces of the bodies, as well as also partly inside them if they are composed of porous material. When the binding agent has set, the bodies are therefore bonded to one another at the contact points. A special advantage with such a design is that, as mentioned, the bodies may consist of porous and therefore lightweight material that, by the covering with a thin layer of binding agent cannot absorb the heated liquid that is to be introduced into the storage vessel. Throughout this description, the invention has been discussed mainly regarding the storage of heat energy in a liquid. It shall be emphasised though, that the invention also covers the use of the basic principles of the invention for the thermal storage of cooling energy in a liquid. Even if water is the liquid that is normally used for thermal storage of heat and cooling energy the invention likewise covers the use of other liquids for this purpose.

The man skilled in the art will realise that different modifications and changes may be made to the present invention without departure from the framework of the invention as defined by the enclosed patent claims.

Claims

PATENT CLAIMS

1. A storage vessel (100; 300) for thermal storage of energy in a liquid contained in the storage vessel, whereby there is a temperature stratification of the liquid (A, B, C, D, E, F) in the storage vessel, and having an input device (111 ; 211 ; 311) for liquid (UV) being provided with stratification channels (116, 117, 118) for feeding in liquid (UV) containing additional thermal energy at different levels in the storage vessel corresponding to the temperature (Tuv) of the supplied liquid, characterised in that the stratification channels are formed in a filler material (113; 113A, 113B, 113C) in the input device (111; 211; 311), in that the filler material consists of a multitude of separate bodies (113;113 A, 113B, 113C) between which the stratification channels (116, 117, 118) are formed and that bear on one another substantially with a point contact (P) between them.

2. A storage vessel (100; 300) according to claim 1, characterised in that a multitude of small stratification channels (116, 117, 118) are formed in the filler material (113; 113 A,

113B, 113C), said channels or alternatively different sections thereof being directed in mutually different directions and in that the stratification channels directly or indirectly communicate with a liquid inlet (119) to the input device and with the liquid (A, B, C, D, E, F) in the interior of the storage vessel, respectively.

3. A storage vessel (100; 300) according to claims 1 or 2, characterised in that the separate bodies (113; 113A, 113B, 113C) of the filler material loosely engage each other.

4. A storage vessel (100; 300) according to claims 1 or 2, characterised in that the separate bodies (113; 113A, 113B, 113C) of the filler material are bonded to one another.

5. A storage vessel (100; 300) according to any of claims 1-4, characterised in that the bodies (113; 113 A, 113B, 113C) have a generally spherical shape.

6. A storage vessel (100; 300) according any of claims 1-5, characterised in that the bodies (113) have a uniform size.

7. A storage vessel (100) according any of claims 1-5, characterised in that the bodies (113A, 113B, 113C) are present in at least two different sizes, whereby the bodies (113C) having the largest size are provided closest to the liquid inlet (119) to the input device (211) and the bodies (113 A) having the smallest size are provided closest to the interior of the storage vessel.

8. A storage vessel (100; 300) according to any of claims 1-5, characterised in that the input device (111; 211; 311) is formed by a liquid-impermeable outer casing (112) that contains the filler material (113A, 113B, 113C) and that presents an open side toward the interior of the storage vessel and in that the input device (111; 211; 311) at the open side casing is provided with a liquid-permeable wall (120).

9. A storage vessel (100; 300) according to claim 8, characterised in that the input device (111; 211; 311) at the open side extends from the upper part of the storage vessel over a greater part of the height of the storage vessel.

10. A storage vessel (100) according to any of claims 1-9, characterised in that the input device (111; 211) is placed on the outside of an outer wall (101) of the storage vessel.

11. An apparatus (111; 211; 311) for feeding liquid (UV) containing additional thermal energy to a storage vessel (100; 300) for the thermal storage of energy, and having stratification channels (116, 117, 118) for feeding liquid into the storage vessel at different levels corresponding to the temperature (Tuv) of the supplied liquid, characterised in that the stratification channels are formed in a filler material (113; 113A, 113B, 113C), in that the filler material consists of a multitude of separate bodies (113; 113A, 113B, 113C) between which the stratification channels (116, 117, 118) are formed and that bear on each other substantially with a point contact (P) between them.

12. An apparatus (111; 211; 311) accordmg to claim 11, characterised in that in the filler material (113; 113A, 113B, 113C) are formed a multitude of small stratification channels

(116, 117, 118) that, or different sections of which, are directed in mutually different directions and in that the stratification channels directly or indirectly communicate with a liquid inlet (119) to the input device and with the liquid (A, B, C, D, E) in the interior of the storage vessel, respectively.

13 An apparatus (111; 211; 311) according to claims 11 or 12, characterised in that the separate bodies (113A, 113B, 113C) of the filler material loosely engage one another.

14. An apparatus (111; 211; 311) according to claims 11 or 12, characterised in that the separate bodies (113A, 113B, 113C) of the filler material are adhered to one another.

15. An apparatus (111; 211; 311) according to any of claims 11-14, characterised in that the bodies (113 A, 113B, 113C) have a generally spherical shape.

16. An apparatus (111; 311) according to any of claims 11-15, characterised in that the bodies (113) are of a uniform size.

17. An apparatus (211) according to any of claims 11-15, characterised in that the bodies (113A, 113B, 113C) are present in at least two different sizes, whereby the bodies (113C) having the largest size are provided closest to the liquid inlet (119) to the input device (211) and the bodies (113A) having the smallest size are provided closest to the interior of the storage vessel.

18. An apparatus (111; 211; 311) according to any of claims 11-17, characterised in that it consists of a liquid-impermeable outer casing (112) that contains the filler material (113; 113 A, 113B, 113C) and that has an open side and in that at the open side of the casing it is provided with a liquid-permeable wall (120).

19. A method of supplying liquid (UV) containing additional thermal energy to a storage vessel (100; 300) for thermal storage of energy in a liquid contained therein, whereby temperature stratification is achieved in the liquid (A, B, C, D, E, F) in the storage vessel and the supply of liquid (UV) takes place at different levels in the storage vessel, corresponding to the temperature (T_uv) of the supplied liquid (UV), whereby the supplied liquid before entering the storage vessel is divided into sub-streams (115) that are led through the stratification channels (116, 117, 118) in an input device (111; 211; 311), characterised in that the sub-streams (115) of the supplied liquid (UV) are conducted through stratification channels (116, 117, 118) formed in a filler material consisting of separate bodies ( 113 ; 113 A, 113B, 113C) in the input device (l l l; 211; 311).

20. A method according to claim 19, characterised in that the sub-streams (115) of the supplied liquid (UV) are conducted through a multitude of small separate^' stratification channels (116, 117, 118) in the input device (111; 211; 311), said stratification channels being extended in different directions and being mutually connected to each other and in that the sub-streams of the liquid in the different channels and/or in sections of each of the channels are conducted in mutually different directions, whereby the supplied liquid through the channels is drained substantially equally well in the different directions.

21. A method according to claims 19 or 20, characterised in that the supplied liquid (UV) in the sub-streams (115) is transferred substantially freely from the channels (116, 117, 118) to the interior of the storage vessel (100; 300).

22. A method according to any of claims 19-21, characterised in that the sub-streams (115) of the supplied liquid (UV) are led into the interior of the storage vessel (100) through an outer wall (101) thereof.