Heat storage device

Abstract

A thermal storage device (100, 300, 600) for an air conditioning apparatus comprises: a phase change material, PCM (102, 302, 602); a plurality of thermally conductive elements (104, 304, 604); and a heat sink (106, 306, 606) in thermal contact with the thermally conductive elements, the heat sink being for transferring heat from a heat exchanger of the air conditioning apparatus to the thermally conductive elements, wherein the thermally conductive elements are embedded within the PCM.

Description

Technical Field

[0001] This disclosure relates to a heat storage device for use in air conditioning equipment. This disclosure also relates to an air conditioning device and a kit, both of which include the heat storage device. Background Technology

[0002] Storing thermal energy through a solid-to-liquid phase change in phase change materials (PCMs) is known. A key challenge in storing thermal energy in PCMs is efficiently transferring heat to the PCM. This is particularly important in the refrigeration loops of air conditioning systems, as the magnitude of the thermal gradient between the PCM and the condenser directly affects the efficiency of the refrigeration cycle. However, efficiently transferring heat to the PCM while maintaining a minimum thermal gradient is very challenging. This is because PCMs typically have better thermal conductivity than insulating materials such as rubber or cork.

[0003] Known systems using PCM to store heat typically employ additional components, such as mechanical agitators, to facilitate heat transfer to the PCM. However, these additional components introduce extra complexity and cost to the system. Furthermore, the mechanical agitator itself consumes energy, which is undesirable. Moreover, the increased complexity can make the system unreliable, thus shortening the device's lifespan or requiring regular maintenance.

[0004] The purpose of this invention is to provide an improved heat storage device for air conditioning equipment. Summary of the Invention

[0005] According to a first aspect of this disclosure, a heat storage device for an air conditioning equipment is provided, the heat storage device comprising: a phase change material PCM; a plurality of thermally conductive elements; and a heat sink in thermal contact with the thermally conductive elements, the heat sink being used to transfer heat from a heat exchanger of the air conditioning equipment to the thermally conductive elements, wherein the thermally conductive elements are embedded within the PCM.

[0006] A thermally conductive element transfers heat from the radiator to the PCM. By embedding the thermally conductive element within the PCM, the thermal resistance to heat transfer into the PCM is reduced, allowing for more efficient heat transfer from the heat exchanger of the air conditioning unit to the PCM. This is because the thermally conductive element can be arranged to reduce the thickness of the PCM, through which heat is transferred via conduction. This allows for a reduction in the thermal gradient, thereby minimizing the impact on the efficiency of the refrigeration cycle. According to the first aspect, the heat storage device can be considered in the form of a removable "thermal battery" in use. This contributes to providing portable air conditioning units that do not require specialized installation or external ducting.

[0007] In one embodiment, the multiple thermally conductive elements comprise an array of fins extending from the heat sink. In this way, the fin structure provides a thermally conductive path through the relatively insulated PCM, thereby improving the PCM's ability to effectively absorb heat.

[0008] In one embodiment, the array of fins comprises fins with a regular polygonal cross-section, such as a honeycomb structure. In another embodiment, the honeycomb structure is filled with PCM. In this way, the fin structure forms part or all of a mechanical package for the PCM, which is desirable when the thermal storage device is intended to be a removable component of an air conditioning unit.

[0009] In one embodiment, the array of fins includes multiple parallel plate fins. In another embodiment, at least some of the parallel plate fins include laterally extending protrusions. These laterally extending protrusions further reduce the thermal resistance to heat transfer into the PCM.

[0010] In one embodiment, the radiator comprises a planar disk or plate. In another embodiment, an array of fins extends from a first side of the radiator. In yet another embodiment, a second side of the radiator opposite the first side is arranged in use to make thermal contact with a heat exchanger of an air conditioning device.

[0011] In one embodiment, the array of fins includes a plurality of fins extending radially outward from the radiator. In another embodiment, at least some of the fins include laterally extending protrusions. In yet another embodiment, the radiator includes a curved portion having an outer surface from which the array of fins extends. In yet another embodiment, the curved portion includes an inner surface arranged to come into thermal contact with a heat exchanger of an air conditioning unit during use, the heat exchanger being concentrically received within the radiator.

[0012] In one embodiment, the thermally conductive element is attached to the heat sink using a brazed joint. In another embodiment, the thermally conductive element is bonded to the heat sink using a thermal adhesive.

[0013] In this embodiment, the fins and heat sink are formed as a single extrusion. This allows for a simpler manufacturing process and a more flexible construction of the thermal storage device.

[0014] In this embodiment, the fins are formed from at least one piece of folded material. Forming fins from a single piece of folded material simplifies the manufacturing process. Folded fins also result in reduced weight and cost. Furthermore, the fins can be manufactured with a lower thickness, thereby improving the overall volumetric efficiency of the thermal storage device.

[0015] In one embodiment, the thermal storage device further includes a housing portion, wherein the housing portion and the heat sink together form at least a portion or all of a mechanical package for the PCM.

[0016] In one embodiment, the housing portion, heat sink, and thermally conductive elements together form a mechanical package for the PCM.

[0017] In this embodiment, the heat sink and heat-conducting element are made of metal, such as aluminum.

[0018] According to a second aspect of this disclosure, an air conditioning device is provided, comprising: any of the aforementioned heat storage devices; and a refrigeration circuit including a condenser and / or an evaporator heat exchanger, wherein the PCM of the heat storage device is arranged to store heat discharged by the condenser and / or evaporator.

[0019] In one embodiment, the air conditioning unit further includes a mechanism arranged to releasably engage with the thermal storage device to allow the thermal storage device to be detached from the air conditioning unit. In this way, when the thermal storage device is near or at its maximum thermal storage capacity, it can be easily detached from the air conditioning unit and replaced with a second thermal storage device that has been "restored," i.e., in which the PCM is in a solid phase.

[0020] According to a third aspect of the invention, a kit is provided, comprising an air conditioning device according to a second aspect and one or more additional heat storage devices according to a first aspect.

[0021] It should be understood that features described with respect to one aspect of this disclosure may be incorporated into other aspects of this disclosure. Attached Figure Description

[0022] Embodiments of this disclosure will now be described by way of example with reference only to the illustrative accompanying drawings, in which:

[0023] Figure 1 A heat storage device for an air conditioning apparatus according to an embodiment of the present disclosure is shown;

[0024] Figure 2 It shows that according to Figure 1 Multiple heat-conducting elements in the embodiments;

[0025] Figure 3 A heat storage device for an air conditioning apparatus according to an embodiment of the present disclosure is shown;

[0026] Figure 4 It shows that according to Figure 3 Multiple heat-conducting elements in the embodiments;

[0027] Figure 5 Multiple thermally conductive elements according to embodiments of the present disclosure are shown;

[0028] Figure 6 Multiple thermally conductive elements according to embodiments of the present disclosure are shown;

[0029] Figure 7 A heat storage device for an air conditioning unit according to an embodiment of the present disclosure is shown; and

[0030] Figure 8 It shows that according to Figure 7 Multiple thermally conductive elements in the embodiments. Detailed Implementation

[0031] Figure 1 A heat storage device 100 for an air conditioning unit according to an embodiment of the present disclosure is shown. The heat storage device 100 includes a phase change material (PCM) 102, a plurality of thermally conductive elements 104, and a radiator 106 in thermal contact with the thermally conductive elements 104. The radiator is adapted to transfer heat from a heat exchanger (e.g., a condenser or evaporator coil 108) of the air conditioning unit to the thermally conductive elements 104. Figure 1 This is an exploded view. In use, the thermally conductive element 104 is embedded within the PCM 102. During use, heat is dissipated through the air conditioning unit's interface 110 by the air conditioning unit's heat exchanger 108, which is in thermal contact with the heat sink 106 of the heat storage device 100. The dissipated heat is then transferred from the heat sink 106 to the PCM 102 via the thermally conductive element 104. The structure of the thermally conductive elements 104, and the fact that they are embedded within the PCM 102, allows for efficient heat transfer into the relatively insulated PCM 102. This is because the thickness of the PCM 102, which transfers heat through conduction, is minimized while still providing sufficient space for the PCM 102.

[0032] Typically, an air conditioning unit (which performs heating and cooling operations) in which a heat storage device 100 according to an embodiment of the present disclosure may be used has an interface 110 arranged to mate with a heat sink 106 of the heat storage device 100. For example, the interface 110 may include a mechanism arranged to releasably engage with the heat storage device 100 to allow the heat storage device to be detached from the air conditioning unit when its heat storage capacity is reached, and to allow another heat storage device to be attached to the air conditioning unit for continued cooling operations. This also applies to air conditioning units according to embodiments of the present disclosure. Figure 3 and 6 The thermal storage device of the embodiment.

[0033] exist Figure 1 In one embodiment, the plurality of thermally conductive elements 104 include an array of fins 104 extending away from the heat sink 106. The array of fins 104 has a regular polygonal cross-section. An example of a fin is shown in... Figure 2 As shown in the cross-section, Figure 2An array of fins 104 comprising a honeycomb structure is shown. The honeycomb structure is filled with PCM 102. Therefore, with such fins 104, in addition to providing efficient heat transfer from the heat sink 106 to the PCM 102, the fins 104 also form at least a portion of the mechanical encapsulation of the PCM 102, which prevents leakage of the PCM 102 when it is in a liquid state. In an embodiment, the height of the fins 104 (i.e., the range of the fins in a direction generally perpendicular to the plane of the heat sink 106) is in the range of 150 mm to 250 mm. In an embodiment, the wall thickness of the fins 104 is in the range of 0.05 mm to 0.20 mm. In an embodiment, the effective diameter or lateral range of each honeycomb fin 104 is in the range of 5 mm to 20 mm. In an embodiment, the total diameter of the thermal storage device 100 is in the range of 200 mm to 300 mm.

[0034] Figure 3 An alternative embodiment of a heat storage device 300 for an air conditioning unit is shown. In these embodiments, a plurality of thermally conductive elements 304 include an array of fins 304 extending radially outward from a heat sink 306. As described above, the fins 304 are embedded within a PCM 302. The heat sink 306 includes a curved portion comprising an outer surface 307 and an inner surface 309, the array of fins 304 extending from the outer surface 307, and the inner surface 309 being arranged to thermally contact a heat exchanger 308 of the air conditioning unit. Specifically, the inner surface 309 is arranged to engage with an interface 310 of the heat exchanger of the air conditioning unit. In this way, the heat exchanger 308 is concentrically received within the heat sink 306. Figure 4 The image shows a cross-section of the heat storage device 300, revealing a radiator 306 and radially outwardly extending fins 304. Although not shown, in an alternative embodiment, the radiator 306 includes a curved portion comprising an inner surface and an outer surface, with an array of fins 304 extending from the inner surface and the outer surface arranged to be in thermal contact with a heat exchanger 308 of an air conditioning unit.

[0035] Figure 5 An alternative embodiment of the cross-section of the thermal storage device 300 is shown, illustrating fins 304 extending radially outward from the heat sink 306, embedded within the PCM 302. The fins 304 are formed from at least one piece of folded material. In one embodiment, the fins 304 are formed as a series of folded material return portions. In another embodiment, the fins 304 are formed from a single piece of folded material. Forming the fins 304 from a single piece of folded material simplifies the manufacturing process. The folded fins 304 also result in reduced weight and cost. Furthermore, the fins 304 can be manufactured with a lower thickness, thereby improving the overall volumetric efficiency of the thermal storage device.

[0036] refer to Figure 6In this embodiment, at least some of the fins 304 include laterally extending protrusions 314. These laterally extending protrusions 314 have been found to further reduce the thermal resistance of heat transfer from the fins 304 to the PCM 302. It should be understood that for a given geometry of the thermal storage device 300, there is typically an optimal density of fins 304 and / or laterally extending protrusions 314. This is because while adding more fins 304 and protrusions 314 per unit volume of the thermal storage device 300 can reduce the total thermal resistance per unit volume, this may come at the cost of reducing the total volume of the PCM 302 that the thermal storage device 300 can accommodate, thus affecting its total thermal storage capacity.

[0037] Figure 7 An alternative embodiment of a heat storage device 600 for an air conditioning unit is shown. In this embodiment, a plurality of heat-conducting elements 604 comprise an array of parallel plate fins 604 extending from a heat sink 606. As described above, the fins 604 are embedded within a PCM 602. At least some of the parallel plate fins 604 can be arranged in a manner similar to... Figure 6 The method shown includes laterally extending protrusions ( Figure 6 (Not shown in the image). In this embodiment, the radiator 606 consists of a generally planar disc or plate, whereby fins 604 extend from a first surface 607 of the radiator 606. A second surface 609 of the radiator 606, opposite the first surface 607, is arranged to make thermal contact with the heat exchanger 608 of the air conditioning unit via an interface 610 during use. Figure 8 Through Figure 7 A cross-section of the heat storage device 600 shows the arrangement of the radiator 606 and the parallel plate fins 604.

[0038] In all the above embodiments, the thermally conductive elements (fins) 104, 304, and 604 can be attached to the heat sinks 106, 306, and 606 by brazing joints or by adhesive bonding. Alternatively, in Figure 3 and Figure 6 In some embodiments, fins 304, 604 and heat sinks 306, 606 may be formed as a single extrusion (optionally with laterally extending protrusions 314 attached). Some embodiments include housing portions 112, 312, 612, which, together with heat sinks 106, 306, 606, form at least a portion of the mechanical package of the PCM. In embodiments, the heat sink and thermally conductive elements are formed of a metal (e.g., aluminum) or any other material that typically has good thermal conductivity compared to the PCM. Suitable PCMs typically have a low thermal conductivity of approximately 0.2 to 0.6 W / mK, such as the RUBITHERM® RT manufactured by Rubitherm Technologies GmbH.

[0039] In the foregoing description, where references are made to an entirety or element having a known, obvious, or foreseeable equivalent, such equivalents are incorporated herein as if separately stated. The true scope of this disclosure should be determined with reference to the claims, which should be interpreted to include any such equivalents. The reader will also understand that entireties or features of this disclosure described as preferred, advantageous, convenient, etc., are optional and do not limit the scope of the independent claims. Furthermore, it should be understood that such optional entireties or features, while potentially beneficial in some embodiments of this disclosure, may be undesirable in others and therefore may be absent.

Claims

1. A heat storage device for use in an air conditioning unit, the heat storage device comprising: Phase change material (PCM); Multiple heat-conducting elements; A radiator that is in thermal contact with the heat-conducting element, the radiator being used to transfer heat from the heat exchanger of the air conditioning equipment to the heat-conducting element; and Shell part, The thermally conductive element is embedded within the PCM. The plurality of heat-conducting elements comprises an array of fins extending from the heat sink. The array of fins described herein includes a honeycomb structure. The honeycomb structure is filled with the PCM. The heat sink includes a flat disk or plate. The housing portion, the heat sink, and the thermally conductive element together form a mechanical package for the PCM.

2. The thermal storage device according to claim 1, wherein the array of fins extends from a first side of the heat sink.

3. The heat storage device according to claim 2, wherein the second side of the heat sink opposite the first side is arranged in use to have thermal contact with the heat exchanger of the air conditioning device.

4. The thermal storage device according to claim 1, wherein the thermally conductive element is attached to the heat sink by a brazing joint.

5. The thermal storage device according to claim 1, wherein the thermally conductive element is bonded to the heat sink with a thermal adhesive.

6. The thermal storage device according to claim 1, wherein the heat sink and the thermally conductive element are formed of metal.

7. An air conditioning device, comprising: The thermal storage device according to any one of claims 1-6; and Refrigeration circuit, including condenser and / or evaporator heat exchanger, The PCM of the heat storage device is arranged to store the heat discharged by the condenser and / or the evaporator.

8. The air conditioning apparatus of claim 7, further comprising a mechanism arranged to releasably engage with the heat storage device to allow the heat storage device to be detached from the air conditioning apparatus.

9. A kit comprising an air conditioning device according to claim 7 or 8 and one or more additional heat storage devices according to any one of claims 1 to 6.

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