HEAT STORAGE DEVICE AND AIR CONDITIONER HAVING SAME

Technical Field

The present invention relates to a heat storage device disposed around a compressor and accommodating a heat storage material that stores therein heat generated by the compressor and also to an air conditioner having the heat storage device.

Background Art

A conventional heat pump air conditioner conducts defrosting during heating by switching a four-way valve from a heating cycle to a cooling cycle when frost has been formed on an outdoor heat exchanger. In this defrosting method, an indoor fan is at a stop, but cold air flows gradually out of an indoor unit, thus posing a problem of warmth being lost.

In view of this, another air conditioner has been proposed having a heat storage device mounted on a compressor in an outdoor unit for the purpose of defrosting by making use of waste heat of the compressor that has been stored in a heat storage tank during heating (see, for example. Patent Document 1).

Fig. 10 is a vertical sectional view depicting an example of a conventional heat storage device. In Fig. 10, a heat storage device 100 is fixed to an outer surface of a partition wall 104 of a compressor 102. The heat storage device 100 includes a metallic member 106 made of an aluminum foil plate, a copper plate or the like and wound around the partition wall 104 so as to be held in contact with the outer surface thereof.

The heat storage device 100 accommodates therein a heat storage material 108 to store heat generated by the compressor 102 through the partition wall 104, and the heat storage material 108 is filled in a space formed by an enclosure 110 having a U-shaped vertical section and the metallic member 106 referred to above. In addition to the heat storage material 108, a heating pipe 112 for heating an inflow refrigerant is disposed inside the space.

Patent Document(s)

Patent Document 1: Japanese Patent No. 2705734

Summary of the Invention

Problems to be solved by the Invention

As described above, in the conventional heat storage device as shown in Fig. 10, the metallic member 106 is wound around the partition wall 104 of the compressor 102 so as to be held in contact with the outer surface thereof, but it is really difficult to manufacture the heat storage device without creating any gap between the metallic member 106 and the partition wall 104. In most cases, a gap between the metallic member 106 and the partition wall 104 is an incident of the manufacturing process. The creation of such a gap means the presence of an air layer that acts as a heat insulating material, thus posing a problem that heat generated by the compressor 102 cannot be efficiently stored in the heat storage material 108.

The present invention has been developed to overcome the above-described disadvantage. It is accordingly an objective of the present invention to provide a heat storage device capable of efficiently storing heat generated by the compressor in the heat storage material and also to provide an air conditioner employing such a heat storage device.

Means to Solve the Problems

In accomplishing the above objective, the present invention is directed to a heat storage device disposed around a compressor to store heat generated by the compressor. The heat storage device includes a heat storage tank having a tank body and a heat storage material accommodated in the tank body to store heat generated by the compressor, a contact member having a flexibility higher than that of the tank body and disposed to confront the compressor so as to be held in close contact therewith, and a heat storage heat exchanger accommodated in the tank body.

Effects of the Invention

According to the present invention, because the heat storage material is accommodated in the tank body, not only is a liquid pressure applied to the contact member, but the heat storage material also expands with heat. In addition, because the contact member has a flexibility and is disposed so as to confront the compressor, the contact member is brought into close contact with the compressor under the liquid pressure of the heat storage material and by thermal expansion of the heat storage material to reduce a gap between the heat storage device and the compressor, i.e., an air layer that acts as a heat insulating material, thus making it possible to efficiently store heat generated by the compressor.

Brief Description of tie Drawings

Fig. 1 is a piping diagram of an air conditioner having a heat storage device according to the present invention.

Fig. 2 is a piping diagram of the air conditioner of Fig. 1, particularly depicting operation thereof and a flow of refrigerant during normal heating.

Fig. 3 is a piping diagram of the air conditioner of Fig. 1, particularly depicting operation thereof and a flow of refrigerant during defrosting/heating.

Fig. 4 is a perspective view of the heat storage device according to the present invention with a compressor and an accumulator installed.

Fig. 5 is an exploded perspective view of the heat storage device of Fig. 4.

Fig. 6 is an exploded perspective view depicting an assembling sequence of the heat storage device of Fig. 4.

Fig. 7 is a cross-sectional view taken along a line VII-VII in Fig. 6(d).

Fig. 8 is an enlarged cross-sectional view in the case where a sheet member provided on the heat storage device of Fig. 4 has a double-layered structure of a resin layer and a metal layer.

Fig. 9 is an enlarged cross-sectional view in the case where the sheet member provided on the heat storage device of Fig. 4 has a three-layer structure of a resin layer, a metal layer and another resin layer.

Fig. 10 is a vertical sectional view of a conventional heat storage device.

Embodiments for Carrying out the Invention

The present invention is directed to a heat storage device disposed around a compressor to store heat generated by the compressor. The heat storage device includes a heat storage tank having a tank body and a heat storage material accommodated in the tank body to store heat generated by the compressor, a contact member having a flexibility higher than that of the tank body and disposed to confront the compressor so as to be held in close contact therewith, and a heat storage heat exchanger accommodated in the tank body.

By this construction, the contact member is brought into close contact with the compressor under liquid pressure of the heat storage material and by thermal expansion of the heat storage material to efficiently store heat generated by the compressor in the heat storage material.

Specifically, the tank body has an opening defined therein at a location confronting the compressor and this opening is closed by the contact member. This configuration allows the contact member to be brought into close contact with the compressor under liquid pressure of the heat storage material and by thermal expansion of the heat storage material to efficiently store heat generated by the compressor in the heat storage material.

Again specifically, the contact member includes a frame having an opening defined therein at a location confronting the compressor and a sheeted member for closing the opening in the frame, wherein the sheeted member has the flexibility higher than that of the tank body, thus enhancing the degree of contact of the sheeted member with the tank body.

Also specifically, the sheeted member is deformable depending on liquid pressure of the heat storage material and, hence, the degree of contact of the sheeted member with the tank body is enhanced.
Preferably, the tank body is made of a resin and the sheeted member includes a first resin layer joined to the tank body and a metal layer laminated on the first resin layer on a side of the compressor. This construction enhances the thermal conductivity, strength and the like of the sheeted member.

Again preferably, the sheeted member further includes a second resin layer laminated on the metal layer on the side of the compressor. This construction further enhances the degree of contact of the sheeted member.

Further preferably, the first resin layer is thicker than the second resin layer and, hence, not only is the degree of contact of the sheeted member enhanced, but a predetermined strength required for the sheeted member is also ensured.

In another aspect of the present invention, an air conditioner includes a compressor and a heat storage device of the above-described type disposed around the compressor.

Embodiments of the present invention are explained hereinafter with reference to the drawings.

Fig. 1 depicts a piping diagram of an air conditioner having a heat storage device according to the present invention. The air conditioner includes an outdoor unit 2 and an indoor unit 4 connected to each other via refrigerant piping.

As shown in Fig. 1, the outdoor unit 2 accommodates therein a compressor 6, a four-way valve 8, a strainer 10, an expansion valve 12, and an outdoor heat exchanger 14, while the indoor unit 4 accommodates an indoor heat exchanger 16 therein. Those constituent elements are connected via refrigerant piping to define a refrigeration cycle.

More specifically, the compressor 6 and the indoor heat exchanger 16 are connected to each other via a first refrigerant pipe 18 to which the four-way valve 8 is fitted, and the indoor heat exchanger 16 and the expansion valve 12 are connected to each other via a second refrigerant pipe 20 to which the strainer 10 is fitted. Also, the expansion valve 12 and the outdoor heat exchanger 14 are connected to each other via a third refrigerant pipe 22, and the outdoor heat exchanger 14 and the compressor 6 are connected to each other via a fourth refrigerant pipe 24.

The four-way valve 8 is located midway on the fourth refrigerant pipe 24, and an accumulator 26 for separating a liquid phase refrigerant and a gas phase refrigerant is provided on the fourth refrigerant pipe 24 on a refrigerant suction side of the compressor 6. The compressor 6 and the third refrigerant pipe 22 are connected to each other via a fifth refrigerant pipe 28, on which a first solenoid valve 30 is provided.

Furthermore, a heat storage tank 32 accommodating a heat storage heat exchanger 34 therein is provided around the compressor 6 and filled with a heat storage material (for example, ethylene glycol aqueous solution) 36 for heat exchanging with the heat storage heat exchanger 34. The heat storage tank 32, the heat storage heat exchanger 34, and the heat storage material 36 constitute a heat storage device.

Also, tine second refrigerant pipe 20 and the heat storage heat exchanger 34 are connected to each other via a sixth refrigerant pipe , and the heat storage heat exchanger 34 and the fourth refrigerant pipe 24 are connected to each other via a seventh refrigerant pipe 40. A second solenoid valve 42 is provided on the sixth refrigerant pipe 38.

The indoor unit 4 accommodates, in addition to the indoor heat exchanger 16, a fan (not shown), vertical wind direction changing blades (not shown), and horizontal wind direction changing blades (not shown). The indoor heat exchanger 16 exchanges heat between indoor air sucked into the indoor unit 4 by the fan and a refrigerant flowing through the indoor heat exchanger 16 so that air heated or cooled by the heat exchange may be blown into a room during heating or cooling, respectively. As occasion demands, the vertical wind direction changing blades vertically change the direction of air discharged from the indoor unit 4 and the horizontal wind direction changing blades horizontally change the direction of air discharged from the indoor unit 4.

The compressor 6, the fan, the vertical wind direction changing blades, the horizontal wind direction changing blades, the four-way valve 8, the expansion valve 12, the solenoid valves 30, 42, and the lie are electrically connected to and controlled by a controller (for example, a microcomputer not shown).

A relation of connection and functioning of the component parts of the above-described refrigeration cycle equipment are explained hereinafter with a flow of the refrigerant, taking the case of the heating operation.

A refrigerant discharged from a discharge port in the compressor 6 passes through the four-way valve 8 and reaches the indoor heat exchanger 16 via the first refrigerant pipe 18. The refrigerant condenses in the indoor heat exchanger 16 upon heat exchange with indoor air, leaves the indoor heat exchanger 16, and passes through the second refrigerant pipe 20 and through the strainer 10, which prevents invasion of foreign substances into the expansion valve 12, before the refrigerant reaches the expansion valve 12. The refrigerant is reduced in pressure by the expansion valve 12 and reaches the outdoor heat exchanger 14 via the third refrigerant pipe 22. The refrigerant then evaporates in the outdoor heat exchanger 14 upon heat exchange with outdoor air and passes through the fourth refrigerant pipe 24, the four-way valve 8, and the accumulator 26, before the refrigerant returns to a suction port in the compressor 6.

The fifth refrigerant pipe 28 branched from the first refrigerant pipe 18 between the discharge port in the compressor 6 and the four-way valve 8 joins the third refrigerant pipe 22 between the expansion valve 12 and the outdoor heat exchanger 14 via the first solenoid valve 30.

Furthermore, the heat storage tank 32 accommodating therein the heat storage material 36 and the heat storage heat exchanger 34 is disposed so as to encircle and contact the compressor 6 to store heat generated by the compressor 6 in the heat storage material 36. The sixth refrigerant pipe 38 branched from the second refrigerant pipe 20 between the indoor heat exchanger 16 and the strainer 10 reaches an inlet of the heat storage heat exchanger 34 via the second solenoid valve 42, and the seventh refrigerant pipe 40 extending from an outlet of the heat storage heat exchanger 34 joins the fourth refrigerant pipe 24 between the four-way valve 8 and the accumulator 26.

Operation of the air conditioner during normal lieating is explained hereinafter with reference to Fig. 2 schematically depicting the operation of the air conditioner of Fig. 1 and a flow of the refrigerant during normal heating.

During normal heating, the first solenoid valve 30 and the second solenoid valve 42 are both closed. In this case, as described above, the refrigerant discharged from the discharge port in the compressor 6 passes through the four-way valve 8 and reaches the indoor heat exchanger 16 via the first refrigerant pipe 18. Having condensed in the indoor heat exchanger 16 upon heat exchange with indoor air, the refhgerant leaves the indoor heat exchanger 16, passes through the refrigerant pipe 20, and reaches the expansion valve 12. The refrigerant is then reduced in pressure by the expansion valve 12 and reaches the outdoor heat exchanger 14 via the third refrigerant pipe 22. Having evaporated in the outdoor heat exchanger 14 upon heat exchange with outdoor air, the refrigerant passes through the fourth refrigerant pipe 24 and through the four-way valve 8 and returns to the suction port in the compressor 6.

Heat generated by the compressor 6 is transferred from an outer wall of the compressor 6 to an outer wall of the heat storage tank 32 and stored in the heat storage material 36 accommodated in the heat storage tank 32.

Operation of the air conditioner during defrosting/heating is next explained with reference to Fig. 3 schematically depicting the operation of the air conditioner of Fig. 1 and a flow of the refrigerant during defrosting/heating. In Fig. 3, solid arrows indicate a flow of refrigerant used for heating, and dotted arrows indicate a flow of refrigerant used for defrosting

If frost is formed and grows on the outdoor heat exchanger 14 during the above-discussed normal heating, the airflow resistance of the outdoor heat exchanger 14 increases to thereby reduce the amount of air passing therethrough, thus resulting in a reduction of the evaporating temperature in the outdoor heat exchanger 14. As shown in Fig. 3, the air conditioner according to the present invention is provided with a temperature sensor 44 for detecting a piping temperature of the outdoor heat exchanger 14, and if this temperature sensor 44 detects a reduced evaporating temperature compared with an evaporating temperature when no frost is formed, the controller outputs a command to shift the air conditioner from the normal heating operation to the defrosting/heating operation.

When the air conditioner is shifted from the normal heating operation to the defrosting/heating operation, the controller controls the first solenoid valve 30 and the second solenoid valve 42 to open them. In this case, in addition to the flow of refrigerant during the normal heating operation as discussed above, part of a gaseous refrigerant discharged from the discharge port in the compressor 6 passes through the fifth refrigerant pipe 28 and the first solenoid valve 30 and joins a refrigerant passing through the third refrigerant pipe 22 to heat the outdoor heat exchanger 14. Having condensed and turned into a liquid phase, the refrigerant passes through the fourth refrigerant pipe 24 and returns to the suction port in the compressor 6 via the four-way valve 8 and the accumulator 26.

Also, part of a liquid refrigerant diverged from the second refrigerant pipe 20 between the indoor heat exchanger 16 and the strainer 10 passes through the sixth refrigerant pipe 38 and the second solenoid valve 42 and absorbs heat from the heat storage material 36 when passing through the heat storage heat exchanger 34. The liquid refrigerant then evaporates and turns into a gas phase. The resultant gaseous refrigerant passes through the seventh refrigerant pipe 40, then joins a refrigerant passing through the fourth refrigerant pipe 24, and finally returns to the suction port in the compressor 6 via the accumulator 26.

Although the refrigerant returning to the accumulator 26 contains a liquid refrigerant returning from the outdoor heat exchanger 14, the latter is admixed with a gaseous high-temperature refrigerant returning from the heat storage heat exchanger 34 to thereby promote evaporation of the liquid refrigerant. Accordingly, it is not likely that a liquid refrigerant may pass through the accumulator 26 and return to the compressor 6, thus making it possible to enhance the reliability of the compressor 6.

At the initiation of defrosting/heating, the temperature of the outdoor heat exchanger 14 is below the freezing point by adhesion of frost, but when the outdoor heat exchanger 14 is heated by the gaseous refrigerant discharged from the discharge port in the compressor 6, frost adhering to the outdoor heat exchanger 14 melts in the vicinity of zero degree and the temperature of the outdoor heat exchanger 14 begins to increase upon termination of melting of the frost. When the temperature sensor 44 detects such a temperature rise of the outdoor heat exchanger 14, a determination is made that defrosting has been completed and the controller outputs a command to shift the defrosting/heating operation to the normal heating operation.

Figs. 4 to 7 depict the heat storage device. As described above, the heat storage device includes the heat storage tank 32, the heat storage heat exchanger 34 and the heat storage material 36. Fig. 4 depicts a state in which the compressor 6 and the accumulator 26 attached to the compressor 6 have been installed in the heat storage device. Fig. 5 is an exploded perspective view of the heat storage device, Fig. 6 depicts an assembling sequence of the heat storage device, and Fig. 7 is a cross-sectional view taken along a line VII-VII in Fig. 6(d).

As shown in Figs. 5 and 6, the heat storage tank 32 includes an upwardly open tank body 46 made of a resin and having a side wall 46a and a bottom wall (not shown), a lid 48 made of a resin for closing an upper opening of the tank body 46, and a packing 50 made of, for example, a silicon rubber and interposed between the tank body 46 and the lid 48. The lid 48 is screwed to the tank body 46. The side wall 46a of the tank body 46 is partly open (part of the side wall 46a confronting the compressor 6) and a contact member 52 is joined to a peripheral edge of this opening 46b to be brought into close contact with an outer surface of the compressor 6.

The contact member 52 includes a frame 54 and a sheeted member 56 and is in the form of a cylinder of a predetermined diameter, a portion of which has been cut away, as a whole. The compressor 6 is accommodated inside the contact member 52 and, hence, the inner diameter of the contact member 52 is slightly greater than the outer diameter of the compressor 6 in consideration of a mounting tolerance and the like.

The frame 54 has an opening 54a defined therein from an intermediate portion to a lower portion thereof in the vertical direction. The sheeted member 56 is joined to the frame 54 to close the opening 54a.

The heat storage heat exchanger 34 is made of, for example, a copper pipe bent into a serpentine configuration and is accommodated within the tank body 46. Also, the heat storage heat exchanger 34 has opposite ends extending upward from the lid 48. One end of the heat storage heat exchanger 34 is connected to the sixth refrigerant pipe 38 (see Fig. 1) and the other end of the heat storage heat exchanger 34 is connected to the seventh refrigerant pipe 40 (see Fig. 1). The heat storage heat exchanger 34 is accommodated in an internal space of the tank body 46, which is delimited by the side wall 46a, the bottom wall and the contact member 52 and in which the heat storage material 36 is filled.

In manufacturing the heat storage device of the above-described construction, as shown in Fig. 6(a), each of the tank body 46, the lid 48, the heat storage heat exchanger 34, the frame 54, the sheeted member 56, and the like is first formed into a predetermined shape. As shown in Fig. 6(b), the sheeted member 56 is subsequently joined to the frame 54 to close the opening 54a in the frame 54, thereby forming the contact member 52. Thereafter, as shown in Fig. 6(c), the contact member 52 is joined to the tank body 46 to close the opening 46b in the tank body 46 and, as shown in Fig. 6(d), the lid 48 is screwed to the tank body 46 and the heat storage material 36 is finally filled in the heat storage tank 32, thus completing the heat storage device.

Although the heat storage heat exchanger 34 is not shown in Fig. 6, the heat storage heat exchanger 34 is secured to the lid 48 and accommodated within the heat storage tank 32 before the lid 48 is screwed to the tank body 46.

Operation of the heat storage device of the above-described construction is explained hereinafter.

As described above, the heat storage device stores in the heat storage material 36 heat generated by the compressor during heating, and when the air conditioner is shifted from the normal heating operation to the defrosting/heating operation, part of a liquid refrigerant diverged from the second refrigerant pipe 20 between the indoor heat exchanger 16 and the strainer 10 absorbs heat from the heat storage material 36 In the heat storage heat exchanger 34. The liquid refrigerant then evaporates and turns Into a gas phase. Accordingly, a higher efficiency of absorbing heat generated by the compressor 6 is desired.

The heat absorption efficiency depends on the degree of contact between the tank body 46 and the compressor 6, but because the compressor 6 is made of a metal and accordingly has an uneven outer surface, it is not easy to enhance the degree of contact between the tank body 46 and the compressor 6.

In view of this, in the heat storage device according to the present invention, the flexible contact member 52 is attached to the tank body 46. When the heat storage material 36 Is filled In the heat storage tank 32, the sheeted member 56 expands toward the outer surface of the compressor 6 under liquid pressure of the heat storage material 36 and is then brought into close contact with the outer surface of the compressor 6, thereby enhancing the heat absorption efficiency.

It Is therefore preferred that the sheeted member 56 be superior in heat resistance, higher In flexibility than the tank body 46, and deformable.

The sheeted member 56 is made of a material such as, for example, PET (polyethylene terephthalate) or PPS (polyphenylene sulfide) and deformable depending on the liquid pressure (in particular, depending on the thickness and having no self-resilience).

When it comes to the frame 54, it is preferred in view of the joining with the sheeted member 56 that the frame 54 is made of the same material as the sheeted member 56. However, if the joint strength with the sheeted member 56 is sufficient, any heat-resistant resin can be employed.

Although the sheeted member 56 may be of a single-layered structure of a resin, in view of the thermal conductivity, strength and the like, it can be of a laminated structure in which a metal layer is laminated on a resin layer.

In the case of the laminated structure, as shown in Fig. 8, it is preferred that the metal layer 58 is positioned outside (on a side confronting the compressor 6) and the resin layer 60 be positioned inside (on a side held in contact with the heat storage material 36). The reason for arranging the metal layer 58 on the side of the compressor 6 is to prevent the sheeted member 56 from being damaged by, for example, an uneven outer surface of the compressor 6. Also, the reason for arranging the resin layer 60 on the side of the heat storage material 36 relative to the metal layer 58 is to prevent corrosion of the metal layer 58.

Further, as shown in Fig. 9, a second resin layer 62 may be laminated on the metal layer 58 so as to be held in close contact with the compressor 6. In this case, it is preferred that the resin layer 60 held in contact with the heat storage material 36 be thicker than the second resin layer 62. The reason for this is that the resin layer 60 acts to prevent the heat storage material 36 from penetrating into the metal layer 58 therethrough.

Industrial Applicability

Because the heat storage device according to the present invention is provided with a contact member to be held in close contact with a compressor and can make a heat storage material efficiently store heat generated by the compressor, the heat storage device according to the present invention is effectively applicable to air conditioners, refrigerators, water heaters, heat pump washing machines, and the like.

Explanation of reference numerals
2 outdoor unit, 4 indoor unit, 6 compressor, 8 four-way valve,
10 strainer, 12 expansion valve, 14 outdoor heat exchanger,
16 indoor heat exchanger, 18 first refrigerant pipe,
20 second refrigerant pipe, 22 third refrigerant pipe,
24 fourth refrigerant pipe, 26 accumulator, 28 fifth refrigerant pipe,
30 first solenoid valve, 32 heat storage tank,
34 heat storage heat exchanger, 36 heat storage material,
38 sixth refrigerant pipe, 40 seventh refrigerant pipe,
42 second solenoid valve, 44 temperature sensor.
46 heat storage tank body, 46a side wall, 46b opening in side wall,
48 lid, 50 packing, 52 contact member, 54 frame, 54a opening,
56 sheeted member, 58 metal layer, 60 resin layer,
62 second resin layer.

CLAIMS

1- A heat storage device disposed around a compressor to store heat generated by the compressor, the heat storage device comprising:
a heat storage tank having a tank body and a heat storage material accommodated in the tank body to store heat generated by the compressor;
a contact member having a flexibility higher than that of the tank body and disposed to confront the compressor so as to be held in close contact therewith; and
a heat storage heat exchanger accommodated in the tank body.

2. The heat storage device according to claim 1, wherein the tank body has an opening defined therein at a location confronting the compressor and the opening is closed by the contact member.

3. The heat storage device according to claim 2, wherein the contact member comprises a frame having an opening defined therein at a location confronting the compressor and a sheeted member closing the opening in the frame, wherein the sheeted member has the flexibility higher than that of the tank body.

4. The heat storage device according to ciairr} 3, wherein the sheeted member is deformable depending on liquid pressure of the heat storage material.

5. The heat storage device according to claim 3, wherein the tank body is made of a resin and the sheeted member comprises a first resin layer joined to the tank body and a metal layer laminated on the first resin layer on a side of the compressor.

6. The heat storage device according to claim 5, wherein the sheeted member further comprises a second resin layer laminated on the metal layer on the side of the compressor.

7. The heat storage device according to claim 6, wherein the first resin layer is thicker than the second resin layer.

8. An air conditioner comprising:

a compressor; and

a heat storage device according to claim 1 disposed around the compressor.