WO2012112050A1

WO2012112050A1 - Thermal storage device

Info

Publication number: WO2012112050A1
Application number: PCT/NL2012/050093
Authority: WO
Inventors: Jan Henk Cnossen; Terence Arthur Devlin
Original assignee: Flamco B.V.
Priority date: 2011-02-18
Filing date: 2012-02-17
Publication date: 2012-08-23

Abstract

The present invention relates to a thermal storage device for storing heat or cold, the thermal storage device comprising: -a housing, -a plurality of volumes of phase changing material provided inside the housing, -an inlet for a liquid or gas, -an outlet for a liquid or gas, wherein the thermal storage device is configured to allow the liquid or gas to flow along the volumes of phase changing material in order to exchange heat with the phase changing material.

Description

Title: Thermal storage device

Field of the invention

The present invention relates to a thermal storage device. Thermal storage devices are known in the field of the art. Background of the invention

Many thermal storage devices make use of phase changing materials (pern).

However, in practice it is found to be difficult to provide a simple and effective way of configuring the phase changing materials and providing these in a simple and practical device for thermal storage.

US6247522 discloses a thermal storage device which uses phase changing materials. A disadvantage of the device according to US6247522 is that it is rather complex and difficult to manufacture.

Summary of the invention

The invention provides a thermal storage device for storing heat or cold, the thermal storage device comprising:

a housing,

one or more volumes of phase changing material (pem volumes) provided inside the housing,

- an inlet for a liquid or gas,

an outlet for the liquid or gas,

wherein the thermal storage device is configured to allow the liquid or gas to flow along the volumes of phase changing material in order to exchange heat with the phase changing material.

Generally, a plurality of volumes will be provided, which are separate from one another. However, it is also possible that a single volume of phase changing material is provided. For instance, a layer comprising upstanding ridges or upstanding projections may be provided.

The liquid may be water. Other liquids are also possible. The gas may be air. Other gasses may also be possible.

In an embodiment, the pem volumes are packaged in a packaging material. In an embodiment, the pern volumes are interconnected to form a layer of pem volumes, wherein the thermal storage device comprises - in a sectional view - multiple layers of pem volumes.

In an embodiment, the support structure keeps the layers of pem volumes positioned at a distance from one another, wherein the support structure has an open structure and defines a flow channel between two layers of pem volumes. In a further embodiment, said distance defines a first part of the flow channel and an interspace is provided between the pem volumes in a layer, which interspace defines a second part of each flow channel.

In an embodiment, the packaging material in which the pem volumes are packaged is also the material which interconnects the pem volumes into a layer via connecting zones.

In an embodiment, the thermal storage device comprises a support structure configured for supporting the layers of pem volumes, wherein the support structure is different and separate from the layers of pcm-volumes and from the packaging material of the layers of pcm-volumes.

In an embodiment, the support structure is provided - in a sectional side view - in multiple layers extending between the layers of pem volumes.

In an embodiment, the thermal storage device has a cylinder form, having - in top view - a substantially round shape.

In an embodiment, either the inlet or the outlet is provided centrally, i.e. coaxial with a central axis of the thermal storage device

In an embodiment, the thermal storage device comprises an inner conduit which extends from the inlet or from the outlet to an opposite end of the thermal storage device and ends in a mixing zone.

In an embodiment, both the inlet and the outlet are provided at one side of the thermal storage device.

In an embodiment, the layers of pem volumes extend - in a sectional side view - substantially between a mixing zone at a top end of the thermal storage device and a mixing zone at a bottom end of the thermal storage device.

In an embodiment, the layers of pem volumes extend substantially parallel to the main axis of the thermal storage device.

In an embodiment, the layers of pern volumes extend substantially parallel to a circumferential wall of the thermal storage device.

In an embodiment, the support structure engages a bottom side of the thermal storage device.

In an embodiment, a mixing zone is provided near a bottom end of the thermal storage device, wherein in the mixing zone no pem volumes are present. In an embodiment, the layer of pern volumes and the support layer are rolled onto one another into a roll.

In an embodiment, the support layer comprises a mesh of metal wire.

In an embodiment, the thermal storage device is configured as a modular unit and constructed to be coupled with other, similar thermal storage devices.

In an embodiment, the thermal storage device comprises:

a coupling outlet configured to be coupled to an inlet of a similar thermal storage device and

a coupling inlet, configured for coupling with an outlet of a similar thermal storage device.

In an embodiment, the inlet and outlet are both located at one side of the buffer device, and wherein the coupling outlet and the coupling inlet are both located at an opposite side of the thermal storage device, allowing a second, thermal storage device to be coupled to the first thermal storage device, for increasing the total thermal storage capacity.

The present invention further relates to a layer of pem volumes, provided in a packaging material which interconnects the pem volumes.

In an embodiment, the multiple pem volumes are packaged in a packaging material. In an embodiment, the packaging material in which the pem volumes are packaged is also the material which interconnects the pem volumes into a layer.

In an embodiment, the pem volumes have the shape of a pill. In an embodiment, the pills are circular and flat.

The present invention further relates to a roll, comprising:

a layer of pern volumes which are interconnected, and which are packaged by a packaging material

- a layer of supporting material,

wherein the layer of pem volumes and the layer of supporting material are rolled onto one another into a roll, wherein the layer of supporting material is different and separate from the layer of pem volumes and from the packaging material.

The present invention also relates to multiple thermal storage devices according to claim 1 , coupled to one another.

The present invention further relates to a method of manufacturing a thermal storage device, comprising:

a housing,

a plurality of volumes of phase changing material provided inside the housing, - an inlet for a liquid or gas,

an outlet for a liquid or gas, wherein the thermal storage device is configured to allow the liquid or gas to flow along the volumes of phase changing material in order to exchange heat with the phase changing material,

the method comprising:

- providing at least one layer of phase changing material,

providing at least one layer of a supporting material,

positioning the layer of phase changing material against the supporting material inside the housing.

In an embodiment, the method comprises rolling the layer of phase changing material and the layer of a supporting material onto one another in a roll and positioning the roll inside the housing.

List of figures

Figure 1 shows a layer of phase change material for use in the invention.

Figure 2 shows an orthogonal view of a layer of phase changing material and support structure rolled together into a roll.

Figure 3 shows a sectional side view of a thermal storage device according to the invention.

Figure 4A shows a schematic side view of a thermal storage device according to the invention.

Figure 4B shows a schematic side view of coupled thermal storage devices according to the invention.

Figures 5A and 5B show schematic side views of the coupling of thermal storage devices according to the invention.

Detailed description of the figures

Turning to figure 1 , a webbing or layer 10 of phase changing materials (pcm) is shown. The phase changing material is provided as pills 12 which are encapsulated in a packaging material 14. The packaging material 14 provides a barrier layer around the pills and shields the pcm from the surroundings. The packaging material 14 also interconnects the pills 12 via intermediate zones 16 which extend between the pills 12. The distance 13 between the pills 12 may vary, but a rather compact configuration provides a good volumetric efficiency. The pills 12 are also referred to as pcm volumes 12 or packaged pcm volumes 12.

The provision of the phase changing materials in relatively small, separate volumes provides a relatively large contact surface per volume, i.e. per unit of weight of the phase changing materials. Between the pills 12, interconnected open spaces are provided through which a liquid or gas may flow.

The phase changing material may be any material known as such in the field of the art.

An example is a salt hydrate, in particular magnesium nitrate with graphite. The melting range of this salt hydrate lies between 60 en 80 degrees Celsius. The salt is embedded in a polymer (Thermusol), wherein possible left open volumes are filled with graphite. This material is compressed into substantially hard pills 12. The pills are packaged into a blister padding (BiCell). This blister padding is known from the packaging industry.

Other examples may be paraffin, fatty acid.

The layer 10 of pern volumes is approximately 1 cm thick, i.e. between 0,5 and 2 cm. The pills 12 are circular when seen from the front and a have a substantially uniform thickness. The pills have a substantially flat upper side and a substantially flat bottom side.

The pills 12 in a same layer are positioned at a distance 13 from one another. The space 15 between the pills of a same layer is interconnected and forms a first part 21 A of a channel 21 through which the liquid or gas flows. The pills have a height 17 and a diameter 5. The distance 13 is smaller than the diameter 5, in particular less than 25 percent of the diameter 5.

Turning to figure 2, a layer 10 of packaged pem volumes 12 is shown together with a support structure 20 or support layer 20.

The support material which forms the support layer 20 is a wire mesh, or may be another kind of support material with an open structure. The wire mesh comprises horizontal wires 38 and vertical wires 39.

The support structure 20 is separate from the pem volumes 12, separate from the layer 10 of pem volumes and separate from the packaging material 14 of the pcm-volumes. This allows the packaging to be manufactured from a material that is suitable for packaging and the support structure 20 to be manufactured from a material that is suitable for providing support. Moreover, the packaging material can be held relatively thin in order to provide a good thermal conductivity. If there is no separate support structure, the packaging material should provide the support which requires a relatively thick layer of packaging material, which in turn thermally isolates the pem-buffers and hinders a good functioning of the thermal storage device.

The support structure 20 maintains the layers 10 of pem volumes at a distance 29 from one another. The distance 29 corresponds to a thickness of the support structure 20. The distance 29 provides a second part 21 B of a channel 21 between each layer 10 of pem volumes. Hence, the total channel 21 between two layers 10 of pem volumes through which the gas or liquid flows is formed by the space formed by the distance 29 between the layers 10 of pcm volumes and the space 15 between the pills 12 of each layer 10. A channel 21 therefore comprises a first part 21 A which is formed by an interconnected space 15 between the pcm volumes in each layer 10 and a second part 21 B which is formed by the distance 29 between each layer 20.

The wires of the wire mesh can be made of steel or another suitable metal. The wire may be provided with a coating. The wire mesh has a relatively open structure and can be manufactured from twined thread. The open structure allows the gas or liquid to flow through the channel part 21 B.

The wire mesh and the layer of pcm volumes are rolled onto on another into a roll 24. Once rolled, the combination of the layer of pcm volumes and the support layer 20 provides rigidity, in particular in the lengthwise direction. This allows the roll 24 to stand upright in such a way that the packaged pcm volumes 12 remain in position. Thus, although the layer 10 of pcm volumes in itself does not have substantial rigidity, the support layer 20 provides the rigidity when both layers are rolled onto one another.

It is also possible that sections of layers 10 of pcm volumes and sections of support layers 20 are cut and laid on top of one another. Instead of rolling, there may be alternatives to provide alternating layers 10 of pcm volumes and layers 20 of support material.

The forces of gravity are transferred onto the support structure 20 and carried downward via the vertical wires 38.

The forces are then transferred via the lower edge 41 of the support layer 20.

It is also possible that the wire mesh comprises predominantly diagonal wires.

The layer 10 of packaged pcm volumes 12 and the support layer 20 are rolled onto themselves, such that between each two layers 10 of pcm, a support layer 20 is provided.

In top view, the layer of packaged pcm volumes and the support layer from a double spiral.

A height 23 of the layer 10 of packaged pcm volumes is smaller than a height 25 of the support layer 20. This has a result in that in a lower section 22 of the roll 24, there is no layer of packaged pcm volumes. This will be further discussed herein below.

Turning to figure 3, a thermal storage device 30 is shown. The thermal storage device 30 is a container having a cylindrical form. The thermal storage device 30 has a height 32, a width 34 and a central axis 36. The thermal storage device 30 has an upper side 40, a lower side 42, and a circumferential wall 44. The thermal storage device has a housing 46, which defines an inner space 48. The housing 46 can be metal or plastic or another material, such as fiberglass. The housing 46 may a double wall construction having standard insulation between the walls.

The thermal storage device comprises an inlet 50 and an outlet 52. The inlet 50 and outlet 52 are provided at the top of the housing 30. The inlet 50 goes over in a tube 54 which extends from the top 40 of the housing to a short distance 55 from the bottom end 42 of the thermal storage device 30. Here, the tube 54 ends in an open end. The inlet is attached to the top 40 of the thermal storage device.

In the interior space 48, the layer 10 of pcm volumes 12 and the layer 20 of support material are provided as a roll 24 about the central axis 36. In side view, the layers 10 of pcm extend vertically, and between each layers 10 of pcm, a layer of support material is provided.

It is noted that the although the sectional view shows many layers 10 of pcm volumes and many layers 20 of support material, since the layer 10 and the layer 20 are rolled onto one another, there physically is only one layer 10 of pcm volumes and one layer 20 of support material. As mentioned above, other layer arrangements than a roll are conceivable.

In a lower region 60 of the thermal storage device, there are no pcm volumes 12 provided, but only the support structure. This region is called a mixing zone. A similar mixing zone 62 is provided at the top of the thermal storage device. Here, there also is no support material.

The support material in the lower mixing zone 60 engages the bottom 42 of the thermal storage device 30.

At the lower side 42 of the thermal storage device 30, a coupling inlet 82 and a coupling outlet 80 are provided. The coupling inlet 82 and coupling outlet 80 are closed off with caps 81 , 83. These will be explained further below.

Operation

Turning to figure 4A, a normal operation of the thermal storage device 30 is shown. In use, the inlet 50 and the outlet 52 are coupled to a liquid or gas conduit system, such as a heating system or a heat pump. This means that in use the layers 10 of packaged pcm volumes are continuously immersed in the liquid or gas.

The liquid or gas is pumped into the inlet 50 and flows through the tube 54 to the lower mixing zone 60. Here, the liquid or gas spreads out and flows into the entire mixing zone 60. Next, the liquid or gas flows upward between the layers 10 of pcm. The liquid or gas flows through the layers of support material 20. The support material is a wire mesh, or may be another kind of support material with an open structure, which allows a liquid or gas to pass through. The liquid or gas also flows through the open spaces between the pills 12.

Thus, the support structure 20 has a double function of on the one hand supporting the pcm volumes 12 and preventing the pcm volumes 12 of sagging or collapsing under their own weight, and on the other hand creating an open structure which allows a liquid or gas to pass through. The liquid or gas may exchange heat with the layers 10 of pern volumes during this period. The liquid or gas flows from the lower mixing zone to the upper mixing zone 62.

If the liquid or gas is warm, it will give off its heat to the phase changing material and cool off. The phase changing material will take up the heat and become warmer. If the liquid or gas is cold, i.e. colder than the temperature of the phase changing material, the liquid or gas will take up heat from the phase changing material and become warmer. The layer 10 of pem will then gradually become colder.

Turning to figure 4b, it is possible to couple multiple thermal storage devices 30A, 30B with one another. This results in a thermal storage device having an increased capacity. A feed line (IN) and an Out-line 72 both are branched off in order to be connected with two thermal storage devices 30A, 30B.

Modular units

Turning to figures 5A and 5B, another option for coupling multiple thermal storage devices 30 is shown. The coupling outlet 80 and coupling inlet 82 are provided with caps 81 , 83. These caps 81 , 83 are removed.

A thermal storage device 30B is then coupled with of another thermal storage device 30A. The coupling outlet 80 of unit 30B is coupled to the inlet 50 of unit 30A and the coupling inlet 82 of unit 30B is coupled to the outlet 52 of unit 30A. The bottom side 42 of the unit 30B engages the top side 40 of the unit 30A.

The tubes 54 of the two units 30A, 30B are coupled with one another. A small insert 86 may be required to provide this coupling.

It can be seen in figure 5B that the inlet 50 of the unit 30B is now coupled to two successive pipes 54 which extend all the way down to the lower mixing zone 60 of the bottom unit 30A.

Operation

A liquid or gas enters the combined thermal storage devices 30A, 30B via the inlet

50. The liquid or gas then flows through the tubes 54 down into the lower mixing zone 60 of the lower unit 30B. Here, the liquid or gas starts flowing upward through the layers of supporting material between the layers 10 of pem volumes 12. The liquid or gas also flows through the open spaces between the pills.

After the liquid or gas arrives in the upper mixing zone 62 of the unit 30A, it flows through the outlet 52 of unit 30A and the coupling inlet 82 of unit 30B into the lower mixing zone 60 of the unit 30B. From here, the liquid or gas flows through the layers of support material of the upper unit 30B. Eventually, the liquid or gas arrives in the upper mixing zone

62 of the upper unit 30B. From here, the liquid or gas flows outward through the outlet 52.

Claims

1. Thermal storage device (30) for storing heat or cold, the thermal storage device comprising:

a housing (46),

one or more volumes (12) of phase changing material (pcm volumes) provided inside the housing,

an inlet (50) for a liquid or gas or a gas,

an outlet (52) for the liquid or gas or a gas,

wherein the thermal storage device is configured to allow the liquid or gas or gas to flow along the one or more volumes of phase changing material in order to exchange heat with the phase changing material.

2. Thermal storage device of claim 1 , wherein the one or more pcm volumes (12) are packaged in a packaging material (14).

3. Thermal storage device of claim 1 or 2, wherein the pcm volumes (12) are

interconnected to form a layer (10) of pcm volumes, wherein the thermal storage device comprises - in a sectional view - multiple layers (10) of pcm volumes.

4. Thermal storage device of any of claims 1 - 3, wherein the packaging material (14) in which the one or more pcm volumes are packaged is also the material which interconnects the pcm volumes into a layer via connecting zones (16).

5. Thermal storage device of any of claims 3 - 4, comprising a support structure (20) configured for supporting the layers (10) of pcm volumes, wherein the support structure is different and separate from the layers (10) of pcm-volumes and from the packaging material (14) of the layers of pcm-volumes.

6. Thermal storage device of claim 5, wherein the support structure is provided - in a sectional side view - in multiple layers (20) extending between the layers (10) of pcm volumes.

7. Thermal storage device of claim 6, wherein the support structure keeps the layers of pcm volumes positioned at a distance (29) from one another, wherein the support structure has an open structure and defines a flow channel (21) between two layers of pcm volumes.

8. Thermal storage device of any of the previous claims, wherein the thermal storage device has a cylinder form, having - in top view - a substantially round shape.

9. Thermal storage device of any of the previous claims, wherein either the inlet or the outlet is provided centrally, i.e. coaxial with a central axis (36) of the thermal storage device

10. Thermal storage device of any of the previous claims, comprising an inner

conduit (54) which extends from the inlet (50) or from the outlet (52) to an opposite end of the thermal storage device and ends in a mixing zone (60).

1 1. Thermal storage device of any of the previous claims, wherein both the inlet and the outlet are provided at one side (40) of the thermal storage device.

12. Thermal storage device of any of the previous claims, wherein the layers (10) of pcm volumes extend - in a sectional side view - substantially between a mixing zone (62) at a top end of the thermal storage device and a mixing zone (60) at a bottom end of the thermal storage device.

13. Thermal storage device of any of the previous claims, wherein the layers (10) of pcm volumes (12) extend substantially parallel to the main axis (36) of the thermal storage device.

14. Thermal storage device of any of the previous claims, wherein the layers (10) of pcm volumes (12) extend substantially parallel to a circumferential wall (44) of the thermal storage device.

15. Thermal storage device of any of the previous claims, wherein the support structure (20) engages a bottom side (42) of the thermal storage device.

16. Thermal storage device of any of the previous claims, wherein a mixing zone (60) is provided near a bottom end of the thermal storage device, wherein in the mixing zone no pcm volumes (12) are present.

17. Thermal storage device of any of the previous claims, wherein the layer (10) of pcm volumes and the support layer (20) are rolled onto one another into a roll (24).

18. Thermal storage device of any of the previous claims, wherein the support layer comprises a mesh of metal wire (38, 39).

19. Thermal storage device of any of the previous claims, configured as a modular unit and constructed to be coupled with other, similar thermal storage devices.

20. Thermal storage device of claim 19, comprising

a coupling outlet (80) configured to be coupled to an inlet (50) of a similar thermal storage device and

a coupling inlet (82) , configured for coupling with an outlet (52) of a similar thermal storage device.

21. Thermal storage device of claim 19 or 20, wherein the inlet (50) and outlet (52) are both located at one side (40) of the buffer device, and wherein the coupling outlet and the coupling inlet are both located at an opposite side of the thermal storage device, allowing a second, thermal storage device to be coupled to the first thermal storage device, for increasing the total thermal storage capacity.

22. Layer of pcm volumes, provided in a packaging material which interconnects the pcm volumes.

23. Layer of claim 22, wherein the multiple pcm volumes are packaged in a

packaging material and have a substantially pill shape.

24. Layer of claim 22 or 23, wherein the packaging material in which the pcm

volumes are packaged is also the material which interconnects the pcm volumes into a layer.

25. Layer of any of claims 22 - 24, wherein the pern volumes have the shape of a pill and are positioned at distance from one another, wherein the distances define an interspace between the pem volumes.

26. Roll (24), comprising:

a layer (10) of pem volumes which are interconnected and which are packaged by a packaging material,

a layer (20) of supporting material,

wherein the layer (10) of pem volumes and the layer (20) of supporting material are rolled onto one another into a roll (24), wherein the layer (20) of supporting material is different and separate from layer of pcm-volumes and from the packaging material.

27. Multiple thermal storage devices (30) according to claim 1 , coupled to one

another.

28. Method of manufacturing a thermal storage device, comprising:

a housing (46),

a plurality of volumes (12) of phase changing material provided inside the housing,

an inlet (50) for a liquid or gas,

an outlet (52) for a liquid or gas,

wherein the thermal storage device is configured to allow the liquid or gas to flow along the volumes of phase changing material in order to exchange heat with the phase changing material,

the method comprising:

providing at least one layer (10) of phase changing material,

providing at least one layer (20) of a supporting material,

positioning the layer (10) of phase changing material against the supporting material inside the housing.

29. Method of claim 28, comprising rolling the layer of phase changing material and the layer of a supporting material onto one another in a roll (24) and positioning the roll inside the housing.