JP2012072928A - Heat storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat storage device that combines durability, even though using a heat storage material the main component of which is water having low cost and high heat capacity.SOLUTION: The heat storage device includes: the heat storage material 12 containing the water; a heat storage tank for keeping the heat storage material 12 internally; a heat storage exchanger, which is arranged as immersed in the heat storage tank, for performing heat exchange between the heat storage material and a heating medium; and a protection unit, which is arranged to come into contact with an interface between the heat storage material and an air layer of an upper part of the heat storage material, for isolating the heat storage exchanger from the interface. Accordingly, the heat storage exchanger 4 can be prevented from corrosion.

Description

  The present invention relates to a heat storage device that recovers heat stored in a heat storage material containing water using a heat exchanger, and an air conditioner using the heat storage device.

  Conventionally, in heating operation using a heat pump air conditioner, in order to defrost an outdoor heat exchanger, the refrigerant flow is switched from a heating cycle to a cooling cycle by a four-way valve, and high-temperature and high-pressure refrigerant is allowed to flow to the outdoor heat exchanger. It is common. This defrosting method has a disadvantage that the heating effect is impaired because the amount of heat that has been diverted indoors is diverted to the defrost of the outdoor heat exchanger. Also, in heating operation, in order to ensure a blown airflow from a sufficiently heated indoor unit, the indoor unit's piping temperature is raised to a certain temperature and then the indoor ventilation is started. There is time, and this is also a drawback of heat pump air conditioners.

  In order to compensate for these drawbacks, a technique is used in which the amount of heat stored in the heat storage device is used for defrosting or improving the start-up characteristics by incorporating the heat storage device into the refrigeration cycle.

  In such a heat storage device, a heat storage material mainly composed of water having a relatively large heat capacity and a low price is often used. However, in order to prevent freezing at low temperatures, a bivalent material having antifreezing properties such as ethylene glycol is used. It is considered to use a mixed liquid in which alcohol is mixed as a heat storage material (see, for example, Patent Document 1).

  Patent document 1 is an example of such a conventional heat storage device. FIG. 6 is a side view of a conventional heat storage device. The heat storage device 30 includes a heat storage container including a metal heat storage tank 31 and a metal lid 32. Inside the heat storage tank 31, a heat storage material 33 of brine containing water as a main component and mixed with 30% ethylene glycol is accommodated to prevent freezing and corrosion at low temperatures. A first heat exchanger 15 and a second heat exchanger 39 supported by a support frame 34 are provided inside the heat storage material of the heat storage tank 31, and heat storage is mainly performed by a heat storage heater 38. It is also possible to heat and store the heat storage material by radiating heat from the first heat exchanger 37, and the refrigerant flowing through the second heat exchanger 39 is heated to a high temperature by the heat storage material stored by heating. The rise characteristics during heating are improved. Further, an oil film formed on the surface of the heat storage material 33 is formed as a means for suppressing evaporation of the heat storage material 33. Further, the lid 32 is provided with an opening 36 for communicating with the atmosphere, and this opening 36 restricts the release of steam generated from the heated heat storage material 33 to the atmosphere and sets the internal pressure of the heat storage container to a predetermined value. Keep it below the value. As a result, the internal pressure of the heat storage container does not become excessively high, so there is no need for the container to be a pressure resistant container. Further, since the opening 36 has a sufficiently small opening area, excessive release of steam and heat loss due to the release can be suppressed.

Japanese Patent Laid-Open No. 10-288359

However, in the heat storage device described in Patent Document 1, there is a description of an oil film formed on the surface of the heat storage material as an evaporation suppression means, but it is unclear what kind of oil film is used. For example, when organic silicon oil is used, organic acids such as formic acid and acetic acid are generated by hydrolysis in the container, and as a result, surface layer corrosion of the heat exchanger immersed in the heat storage material occurs.
In addition, the organic silicon oil dissolves in the water of the heat storage material, and eventually the heat storage material evaporates and the heat storage capacity decreases with time.

  Also, if the heat storage material transpirations or the heat storage device tilts, if the heat exchanger is exposed to the air layer from the surface of the heat storage material and the heat exchanger is in contact with the interface between the air and the heat storage material Interfacial corrosion may occur. Interfacial corrosion occurs when a metal such as copper is exposed to an atmosphere having a pH of 5 or less in which water and oxygen are present, and causes ant nest corrosion locally from the metal surface. The ant nest-like corrosion has a problem that the erosion into the metal is faster than the surface layer corrosion, and the durability of the heat exchanger and the piping through which the heat medium flows is impaired.

  Therefore, an object of the present invention is to provide a heat storage device having durability while using a heat storage material mainly composed of water having a low heat capacity and a large heat capacity.

  In order to achieve the above object, a heat storage device according to the present invention is immersed in a heat storage material containing water, a heat storage tank that holds the heat storage material inside, an air layer that contacts the heat storage material, and the heat storage material. A heat storage heat exchanger that exchanges heat between the heat storage material and the heat medium, and a protective means that is arranged in contact with the interface between the air layer and the heat storage material and isolates the heat storage heat exchanger from the interface. Prepare.

  Furthermore, it has a cover part which has the opening which the said heat storage heat exchanger penetrates, and is provided with the heat exchanger connector which connects the said cover part and the said heat storage heat exchanger as said protection means.

  According to the present invention, in the heat storage tank that holds the heat storage material containing water therein, the heat storage heat exchanger is isolated from the interface between the heat storage material and the air layer using the protection means. It is possible to provide a heat storage device that prevents interface corrosion, is inexpensive, and has both heat capacity and durability.

Sectional drawing of the thermal storage apparatus which concerns on Embodiment 1 of this invention Sectional drawing of the thermal storage apparatus which concerns on Embodiment 2 of this invention The block diagram of the air conditioner using the thermal storage apparatus which concerns on this invention The schematic diagram which shows the operation | movement at the time of normal heating of the air conditioner of FIG. 3, and the flow of a refrigerant | coolant. The schematic diagram which shows the operation | movement at the time of defrosting and heating of the air conditioner of FIG. 3, and the flow of a refrigerant | coolant Cross-sectional view of a conventional heat storage device

  1st invention is arrange | positioned so that it may immerse in the thermal storage material which contains water, the thermal storage tank holding a thermal storage material inside, the air layer which contacts a thermal storage material, and a thermal storage material, and a thermal storage material and a heat medium A heat storage device that exchanges heat between the heat storage device and a heat storage device that is arranged in contact with the interface between the air layer and the heat storage material, and provides a protection means that isolates the heat storage heat exchanger from the interface It is a thing.

  Thereby, corrosion of the heat storage heat exchanger at the interface between the heat storage material and the air layer can be prevented.

  In the second invention, the heat storage tank has a lid portion having an opening through which the heat storage heat exchanger passes, and the protection means is a heat exchanger connecting the lid portion and the heat storage heat exchanger. Corrosion of the heat storage heat exchanger at the interface between the material and the air layer can be prevented.

In a third aspect of the invention, the heat storage tank has a lid portion having an opening through which the heat storage heat exchanger passes, and an opening through which the heat storage heat exchanger passes is provided in a part of the lid portion so that the portion contacts the interface. Since the protection means is configured by being arranged in the cover, the protection means can be configured by the lid portion, so that it can be configured at low cost.

  The fourth aspect of the invention is provided with an internal pressure adjusting means for communicating the air layer and the atmosphere at a position in contact with the air layer of the lid, and opens at a predetermined pressure smaller than the pressure resistance strength of the heat storage tank. A heat storage tank can be formed even if it is not a pressure vessel.

  According to the fifth aspect of the present invention, a part of the heat storage heat exchanger is made of copper or aluminum, and corrosion can be prevented even when the heat exchanger is made of copper or aluminum.

  In addition, the sixth invention is a mixture of water and non-freezing dihydric alcohol as the main component of the heat storage material, and is inexpensive and has a large heat capacity. Therefore, the sixth invention is suitable as a heat storage material and freezes the heat storage material. Can be prevented. Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In the following embodiments, the present invention will be described with reference to the drawings, but the present invention is not intended to be limited to these.

(Embodiment 1)
1 is a cross-sectional view of a heat storage device according to Embodiment 1 of the present invention. In FIG. 1, a heat storage device 1 includes a heat storage container including a box portion 2 and a lid portion 10, internal pressure adjusting means 5 disposed in the lid portion 10, a heat storage material 12 and a heat storage material 12 filled in the heat storage container. It is comprised from the thermal storage heat exchanger 4 and the heat exchanger connector 8 immersed in the. An air layer 6 exists above the heat storage material 12.

  The box part 2 and the cover part 10 are made of polyphenylene sulfide (PPS) resin. The internal pressure adjusting means 5 is made of a rubber material having a pinhole, and is fitted at a position in contact with the air layer 6 in the lid portion 10. The heat storage material 12 is a mixture of ethylene glycol, which is an antifreezing dihydric alcohol, and water, and the mixing ratio is 70% of water with respect to 30% of ethylene glycol. Ethylene glycol has a boiling point of 198 ° C. and a melting point of −13 ° C. By using the above mixing ratio, the boiling point is 103 ° C. and the freezing temperature is −15 ° C. The filling amount of the heat storage material 12 is set so that the maximum volume is smaller than the value obtained by removing the immersion volume of the heat storage material 12 of the heat storage heat exchanger 4 and the heat exchanger connection 8 from the volume of the box portion 2. . As a result, the air layer 6 is secured. The heat storage heat exchanger 4 is made of a copper serpentine tube, and is connected and fixed to the lid portion by a heat exchanger connector 8, and is connected to an external pipe after the heat storage device is completed. The heat exchanger connector 8 is made of brass and has a communication hole for penetrating the heat storage heat exchanger 4 therein. After the heat storage heat exchanger 4 is inserted into the communication hole, the heat storage heat is generated all around the insertion port. It is welded to the exchanger 4 and formed integrally. Further, the heat exchanger connector 8 has a sufficiently large length with respect to the air layer 6, penetrates the air layer 6, and the insertion port is disposed at a position immersed in the heat storage material 12. As a result, the heat storage heat exchanger 4 made of copper tube can be isolated from the air layer 6 and held inside the heat storage device 1.

  In FIG. 3, the structure of the air conditioner provided with the heat storage apparatus which concerns on this invention is shown. The air conditioner according to the present invention includes an outdoor unit 56, an indoor unit 14, and a refrigerant pipe that connects them.

  The outdoor unit 56 includes a compressor 58, a four-way valve 25, an expansion valve 24, and an outdoor heat exchanger 20, a pipe 26 that connects the refrigerant discharge port of the compressor 58 and the four-way valve 25, and a refrigerant of the compressor 58. A pipe 28 that connects the suction port and the four-way valve 25, a pipe 66 that connects the four-way valve 25 and the outdoor heat exchanger 20, and a pipe 64 that connects the outdoor heat exchanger 20 and the four-way valve 25 are provided.

  The indoor unit 14 includes an indoor heat exchanger 22, a blower fan (not shown), and a louver (not shown) that controls the blowing direction.

  The pipe 62 is installed between the expansion valve 24 and the indoor heat exchanger 22 and connects the outdoor unit 56 and the indoor unit 14. The pipe 60 is installed between the indoor heat exchanger 22 and the four-way valve 25 and connects the outdoor unit 56 and the indoor unit 14.

  Further, in the outdoor unit 56, the pipe 40 connecting the pipe 26 and the pipe 64, the first electromagnetic valve 42 installed in the pipe 40, the pipe 68 connecting the pipe 28 and the pipe 62, and the pipe 68 are installed. The second electromagnetic valve 44 is provided.

  The heat storage device 1 according to the present invention is on a pipe 68, and the heat storage heat exchanger 4 is connected to the pipe 68. The heat storage device 1 is in close contact with the compressor 58, and is disposed between the pipe 28 and the second electromagnetic valve 44.

  The compressor 58, the blower fan, the louver, the four-way valve 25, the expansion valve 24, the first electromagnetic valve 42, and the second electromagnetic valve 44 are electrically connected to a control device (not shown, for example, a microcomputer). Controlled by

  FIG. 4 is a schematic diagram illustrating an operation and a refrigerant flow during normal heating of the air conditioner according to the present invention. The refrigerant discharged from the discharge port of the compressor 58 reaches the indoor heat exchanger 22 via the pipe 26 and the four-way valve 25. The refrigerant condensed by exchanging heat with indoor air having a temperature lower than that of the refrigerant in the indoor heat exchanger 22 reaches the expansion valve 24 via the pipe 62. The refrigerant depressurized in the expansion valve 24 reaches the outdoor heat exchanger 20 through the pipe 64. In the outdoor heat exchanger 20, the refrigerant evaporated by exchanging heat with outdoor air having a temperature higher than that of the refrigerant returns to the suction port of the compressor 58 through the pipe 66, the four-way valve 25, and the pipe 28.

  The heat storage device 1 according to the present invention is installed in close contact with the compressor 58 and accumulates heat generated by the compressor 58 in the heat storage material 12. During normal heating, the first solenoid valve 42 and the second solenoid valve 44 are controlled to be closed. Further, as the temperature of the compressor 58 rises and falls, the internal pressure fluctuates also inside the heat storage device 1, but the internal pressure adjusting means 5 opens at a predetermined pressure smaller than the pressure resistance strength of the heat storage tank. A heat storage tank can be formed without this.

  FIG. 5 is a schematic diagram showing the operation and refrigerant flow during defrost heating in the configuration of the air conditioner shown in FIG. 3. Hereinafter, the operation at the time of defrost heating will be described with reference to FIG. In the figure, the solid arrow indicates the flow of the refrigerant used for heating, and the broken arrow indicates the flow of the refrigerant used for defrosting.

  When the outdoor heat exchanger 20 is frosted during the normal heating operation described above and the frost formed grows, the ventilation resistance of the outdoor heat exchanger 20 increases and the air flow decreases, and the evaporation temperature in the outdoor heat exchanger 20 is reduced. descend. As shown in FIG. 5, a temperature sensor 70 that detects the piping temperature of the outdoor heat exchanger 20 is provided, and when the temperature sensor 70 detects that the evaporation temperature has decreased as compared to the non-frosting state, Thus, the control signal is switched from the normal heating operation to the defrosting heating operation. When switching to the defrosting heating operation, the first electromagnetic valve 42 and the second electromagnetic valve 44 are controlled to open. In addition to the refrigerant flow during the normal heating operation described above, a part of the gas-phase refrigerant coming out of the discharge port of the compressor 58 joins the refrigerant passing through the pipe 40 and the first electromagnetic valve 42 and passing through the pipe 64. After the outdoor heat exchanger 20 is heated and condensed, it reaches the suction port of the compressor 58 via the pipe 66, the four-way valve 25, the pipe 28, and the accumulator 72.

  A part of the liquid phase refrigerant branched from the pipe 62 passes through the pipe 68 and the second electromagnetic valve 44, absorbs heat from the heat storage material 12 in the heat storage heat exchanger 4, evaporates, and joins the pipe 68 to the pipe 28. Return to the suction port of the compressor 58.

The refrigerant returning to the accumulator 72 includes the liquid phase refrigerant returning from the outdoor heat exchanger 20. By mixing this with the high-temperature gas phase refrigerant returning from the heat storage heat exchanger 4, the liquid phase refrigerant is returned. The evaporation of the refrigerant is promoted, and the liquid-phase refrigerant does not return to the compressor 58 through the accumulator 72, so that the reliability of the compressor 58 can be improved.

  The temperature of the outdoor heat exchanger 20 that has become below freezing due to the attachment of frost at the start of the defrost heating is heated by the gas-phase refrigerant discharged from the discharge port of the compressor 58, and the frost is melted at around zero degrees. When finished, the temperature of the outdoor heat exchanger 20 begins to rise again. When the temperature sensor 70 detects the temperature rise of the outdoor heat exchanger 20, it is determined that the defrosting is completed, and an instruction from the defrost heating operation to the normal heating operation is output from the control device.

  As described above, the heat storage device 1 according to the present invention is in close contact with the compressor 58 in the air conditioner, accumulates the heat generated in the compressor 58 during the heating operation in the heat storage material 12, and changes from the normal heating operation to the defrosting heating operation. When the transition is made, a part of the liquid-phase refrigerant diverted from the pipe 62 through the indoor heat exchanger 22 absorbs heat from the heat storage material 12 in the heat storage heat exchanger 4 and is evaporated and vaporized.

  In addition, the heat storage device 1 according to the present invention needs to prevent the copper heat storage heat exchanger 4 from being exposed to a corrosive atmosphere containing oxygen in the heat storage device 1 for a long time of several years or more. The heat storage device 1 according to the present invention can prevent corrosion of the heat storage heat exchanger 4 while using the heat storage material 12 whose main component is water that is inexpensive and easy to handle. The heat storage heat exchanger 4 can be protected from corrosion by the heat exchanger 8 that isolates the heat storage heat exchanger 4 from the air layer 6 in the heat storage tank.

  In the present embodiment, the heat exchanger connector 8 serving as the protection means in the present invention is integrally formed with the heat storage heat exchanger 4 by welding. As a result, the heat storage heat exchanger 4 is isolated from the air layer 6 inside the heat storage device 1. In addition, the joining method of the heat exchanger connector 8 and the heat storage heat exchanger 4 is not limited to welding. Adhesiveness should just be ensured by the use of a sealing material, adhesive, or screw fastening.

  In the present embodiment, the heat storage device 1 has been described as using the heat of the compressor 58, but it may be heated by a heater or store heat of other piping parts.

(Embodiment 2)
FIG. 2 is a cross-sectional view of the heat storage device according to Embodiment 2 of the present invention. In FIG. 2, a heat storage device 1 includes a heat storage container including a box portion 2 and a lid portion 10, internal pressure adjusting means 5 disposed in the lid portion 10, a heat storage material 12 and a heat storage material 12 filled in the heat storage container. It is comprised from the thermal storage heat exchanger 4 immersed in the. Moreover, the air layer 6 exists in the upper part of the thermal storage material 12, and comprises the interface between the thermal storage materials.

  Since the box part 2, the cover part 10, the internal pressure adjusting means 5, and the heat storage material 12 are the same as those in the first embodiment, detailed description thereof is omitted. The heat storage heat exchanger 4 is made of an aluminum serpentine tube, and is connected and fixed to the lid portion by a heat exchanger connector 8, and is connected to an external pipe after the heat storage device is completed. The heat exchanger connector 8 is made of brass and has a communication hole for passing the heat storage heat exchanger 4 therein. After inserting the heat storage heat exchanger 4 into the communication hole, heat storage heat exchange is performed all around the inlet. It is welded to the container 4 and formed integrally. The lid 10 has a recess 74 having a sufficiently large depth with respect to the air layer 6, and the heat exchanger connection 8 is disposed at the deepest portion of the recess 74 that penetrates the air layer 6. As a result, the heat storage heat exchanger 4 made of aluminum can be held inside the heat storage device 1 while being isolated from the air layer 6. Therefore, as in the first embodiment, the copper heat storage heat exchanger 4 can be prevented from being exposed to a corrosive atmosphere containing oxygen in the heat storage device 1 over a long period of time, and the durability of the heat storage device 1 can be improved. .

  INDUSTRIAL APPLICABILITY The present invention can be used for a heat storage device that recovers heat stored in a heat storage material containing water with a heat exchanger and an air conditioner using the heat storage device.

DESCRIPTION OF SYMBOLS 1 Thermal storage apparatus 2 Box part 4 Thermal storage heat exchanger 5 Internal pressure adjustment means 6 Air layer,
8 Heat Exchanger 10 Lid 12 Heat Storage Material 14 Indoor Unit 22 Indoor Heat Exchanger 24 Expansion Valve,
26, 28, 40, 60, 62, 64, 66, 68 Piping 42 First solenoid valve 44 Second solenoid valve,
56 Outdoor unit 58 Compressor 70 Temperature sensor 72 Accumulator

Claims (8)

A heat storage material containing water, a heat storage tank that holds the heat storage material therein, an air layer that is in contact with the heat storage material, and a soaked in the heat storage material, between the heat storage material and the heat medium A heat storage device including a heat storage heat exchanger for performing heat exchange,
A heat storage device, wherein the heat storage device is provided so as to be in contact with an interface between the air layer and the heat storage material and isolates the heat storage heat exchanger from the interface. The heat storage tank has a lid portion having an opening through which the heat storage heat exchanger passes,
The heat storage device according to claim 1, wherein the protection unit is a heat exchange connector that connects the lid and the heat storage heat exchanger. The heat storage tank has a lid portion having an opening through which the heat storage heat exchanger passes,
The protective means is configured by providing an opening through which the heat storage heat exchanger passes in a part of the lid part and arranging the part so as to contact the interface. Heat storage device. 4. The heat storage device according to claim 2, further comprising an internal pressure adjusting unit that communicates the air layer with the atmosphere at a position where the lid portion is in contact with the air layer. 5. The heat storage heat exchanger according to any one of claims 1 to 4, wherein a part of the heat storage heat exchanger is made of copper or aluminum. The said thermal storage material is a thermal storage apparatus of any one of Claims 1-5 which have as a main component the liquid mixture of water and antifreezing dihydric alcohol. The heat storage device according to claim 6, wherein the antifreeze dihydric alcohol is ethylene glycol and / or propylene glycol. An air conditioner comprising the heat storage device according to any one of claims 1 to 7.