JPH1062087A - Shell and tube type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a supercooled state of a thermal storage medium by reducing a secondary flow which occurs when a corner exists on the wall surface of a passage of the thermal storage medium. SOLUTION: Inside a heat transfer tube 60, a rod-shaped body 82a inserted concentrically into the heat transfer tube 60 and a spiral projecting thread 83 are provided. The spiral projecting thread 83 is positioned between the outer peripheral surface of the rod-shaped body 82a and the inner peripheral surface of the heat transfer tube 60 and forms a spiral passage of a thermal storage medium. In a section intersecting perpendicularly the direction of the passage of the thermal storage medium, a circular-arc face C11 is formed is formed in a corner part wherein the inner peripheral surface of the heat transfer tube 60 and the surface of the spiral projecting thread 83 intersect each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shell-and-tube heat exchanger, and more particularly to an internal structure of a heat transfer tube.

[0002]

2. Description of the Related Art Conventionally, a shell-and-tube type heat exchanger (hereinafter simply referred to as "heat exchanger") used for producing supercooled water for ice making or the like is provided inside a heat transfer tube. A rod-shaped flow path forming body is known. For example, this type of heat exchanger is disclosed in
There is one disclosed in Japanese Patent No. 2391. FIG.
As shown in (a), in this heat exchanger, the flow inside the heat transfer tube (a) is between the outer circumferential surface of the flow path forming body (b) and the inner circumferential surface of the heat transfer tube (a). A spiral ridge (c) is provided to project from the outer peripheral surface of the path forming body (b) toward the inner peripheral surface of the heat transfer tube (a).

[0003] The spiral ridge (c) is formed by spirally turning the flow path of water as a heat storage medium in the axial direction around the flow path forming body (b) over substantially the entire length of the heat transfer tube (a). The main flow of water flowing through this flow path is pressed against the inner peripheral surface of the heat transfer tube (a) to reduce turbulence in the flow.

In this flow path, the main flow of water spirals and flows through the flow path, so that the swirl turns around the flow path in a cross section of the flow path (a cross section orthogonal to the flow direction of water). A flow (f1) is generated.

[0005]

However, the above-mentioned conventional heat exchanger has the following problems.

As shown in FIG. 11 (b), in the conventional heat exchanger, at the corner where the inner peripheral surface of the heat transfer tube (a) intersects with the surface of the spiral ridge (c) in the cross section of the flow path, A corner (d) was formed at which both surfaces crossed at an acute angle. Then, in addition to the swirling flow (f1) swirling around the flow path, a secondary flow (f2) due to the presence of the corner (d) was generated near the corner (d).

The secondary flow (f2) causes the corner
Since the flow is stagnant near (d), the water near (d) where heat transfer is good is difficult to mix with the water in other parts of the swirling flow (f1). Therefore, the water near the corner (d) is cooled much more than the water in other parts, and the temperature of the water near the corner (d) is extremely lower than the temperature of the water in the other parts.

By the way, the supercooled state of water is inherently unstable, and water in the supercooled state cancels supercooling and starts icing even with a slight stimulus. Therefore, if there is a part whose temperature is extremely lower than other parts, the temperature difference may be a stimulus (cause) and the supercooled state may be eliminated.

In the conventional heat exchanger, for example, the water near the corner (d) is extremely cooled due to the stagnant flow and becomes a supercooled state of −2 ° C., while the water in the other part flows in the flow direction. And gradually cooled to a supercooled state of -1 ° C, and the supercooled state was sometimes eliminated due to the temperature difference.

That is, in the conventional heat exchanger, it is difficult to maintain a stable supercooled state due to the secondary flow caused by the presence of the corner (d). Therefore, heat transfer tube (a)
There was a high risk that the supercooled water would freeze inside and freeze.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and an object of the present invention is to suppress the secondary flow caused by the corner (d) of the flow path and stably suppress the supercooled state of the heat storage medium. An object of the present invention is to provide a heat exchanger that supercools a heat storage medium while maintaining the same.

[0012]

In order to achieve the above-mentioned object, the means according to the first aspect of the present invention comprises a closed container (51) and a plurality of containers provided in the closed container (51). Heat transfer tube
(60, 60b, 60c), a refrigerant (R) flowing outside the heat transfer tubes (60, 60b) and a heat storage medium flowing inside the heat transfer tubes (60, 60b, 60c).
(W) and a shell-and-tube heat exchanger that exchanges heat with the (W). And each of the above heat transfer tubes (60, 60b)
Inside the rod-shaped body (82a, 82b, 82c) inserted in the heat transfer tube
And the heat transfer tubes (60, 60) and the outer surface of the rods (82a, 82b, 82c).
(b, 60c) and a spiral ridge (83, 83b, 83c) forming a spiral heat storage medium flow path are provided between the inner peripheral surfaces of the heat transfer tubes (60, 60b, 60c). ) And the spiral ridges (83, 83b, 83c) are formed in a circular arc surface.

According to the specific requirements of the above invention, the heat storage medium flowing in the heat transfer tube spirally moves outside the rods (82a, 82b, 82c) and turns in the flow path. And heat transfer tubes
The corners (C11, C21, C31) where the inner peripheral surface of (60, 60b, 60c) and the surface of the spiral ridge (83, 83b, 83c) intersect are formed in an arcuate surface. Generation of the secondary flow is suppressed. As a result, the flow of the heat storage medium is stabilized, and the elimination of the supercooled state of the heat storage medium is avoided.

[0014] Further, in the shell and tube type heat exchanger according to the first aspect, the rod-shaped body (82b, 82c) and the spiral ridge (83b, 83c) are provided.
Are formed in a circular arc surface.

According to the specific requirements of the above invention, the heat transfer tubes (60b, 6
0c) not only at the corners (C21, C31) where the inner peripheral surface of the spiral ridge (83b, 83c) intersects, but also at the outer peripheral surface of the rod-shaped body (82b, 82c) and the spiral ridge (83b, 83c). ) Corners (C22, C3
2) is also formed on an arc surface, so that the occurrence of secondary flow due to the presence of a corner is further suppressed. Therefore, the flow of the heat storage medium is further stabilized, and the supercooled state of the heat storage medium is prevented from being eliminated.

According to a third aspect of the present invention, there is provided a shell and tube type heat exchanger according to any one of the first and second aspects, wherein the rod-like member (82a, 82b) and the spiral ridge are provided. (83, 83b) are integrally formed.

According to the specific requirements of the above invention, the rod-shaped body (82b)
Corner (C2) where the outer peripheral surface of the spiral crosses the surface of the spiral ridge (83b).
2) It is possible to reliably form the arc surface.

According to a fourth aspect of the present invention, there is provided a shell and tube type heat exchanger according to any one of the first and second aspects, wherein the heat transfer tube (60c) and the spiral ridge (83c ) And are integrally formed.

According to the specific requirements of the above invention, the heat transfer tube (60c)
Corner (C3) where the inner peripheral surface of the spiral crosses the surface of the spiral ridge (83c).
The arc surface of 1) can be reliably formed.

[0020]

Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, a regenerative air conditioner (10) using the heat exchanger (50) of the present invention will be described.

As shown in FIG. 1, a regenerative air conditioner (1
0) includes a refrigerant circuit (20) for circulating a refrigerant and a water circuit (30) for circulating water. Therefore, the refrigerant circuit (20) and the water circuit (30) will be described in order.

-Refrigerant circuit (20)-The refrigerant circuit (20) comprises a compressor (21) and a four-way switching valve (22).
The outdoor heat exchanger (23), the outdoor electric expansion valve (EV-1) and the indoor electric expansion valve (EV-2), the indoor heat exchanger (24), and the accumulator (25) are connected to the refrigerant pipe ( A main refrigerant circuit (27), which is connected in order by 26) and is capable of reversible operation, is provided. And the indoor heat exchanger (24) and the indoor electric expansion valve (EV-2)
Is provided in the indoor unit, while other component devices such as the compressor (21) are provided in the outdoor unit.

Further, the refrigerant circulation circuit (20) is provided with a heat storage refrigerant circuit (2a), an ice core circuit (2b), and a hot gas passage (2C). The heat storage refrigerant circuit (2a) is a circuit in which the refrigerant circulates during a cold storage operation or a cooling operation using cold storage, and has one end having an outdoor heat exchanger (23) and an outdoor electric expansion valve (EV-
The other end is between the four-way switching valve (22) and the accumulator (2).
5), a first solenoid valve (SV-1), a preheater (11), a heat storage electric expansion valve (EV-3) as an expansion mechanism,
The supercooling heat exchanger (50) and the second solenoid valve (SV-2) are sequentially connected. The heat exchanger of the present invention is used as this subcooling heat exchanger (50).

The ice core circuit (2b) includes a water circulation circuit described later.
A circuit for generating ice nuclei in (30), one end between the heat storage electric expansion valve (EV-3) and the supercooling heat exchanger (50) in the heat storage refrigerant circuit (2a), the other end Is a subcooling heat exchanger (50)
And a second solenoid valve (SV-2), and a capillary tube (CP) and an ice nucleus generator (13) are connected in order.

The hot gas passage (2C) is used to cool the refrigerant discharged from the compressor (21) during a cooling operation utilizing cold storage or the like.
A circuit for supplying to the (50), one end of which is connected to the discharge side of the compressor (21), the other end of which is connected to the subcooling heat exchanger (50), and a third solenoid valve (SV-3). I have.

-Water circulation circuit (30)-As shown in FIG. 2, the water circulation circuit (30) has a heat storage tank (31).
, A pump (32), a preheater (11), a mixer (33), a subcooling heat exchanger (50), and a subcooling elimination unit (34) by a water pipe (35) as a heat storage medium. A certain water circulation (see the arrow in FIG. 2) is connected in order as possible.

And, the supercooling heat exchanger according to the present invention
Reference numeral (50) denotes a vertical shell-and-tube heat exchanger, which is formed by housing a plurality of heat transfer tubes in a container, as described later. The supercooling heat exchanger (50) exchanges heat between the refrigerant flowing from the refrigerant circuit (20) in the container and the water flowing in the heat transfer tube, and cools the water to a supercooled state during the cold storage operation. It is configured to be.

The preheater (11) is a double-pipe heat exchanger, in which refrigerant flows outside the inner pipe, water flows inside the inner pipe, and ice water flowing from the heat storage tank (31) is removed. Heating and water plumbing
The ice flowing through (35) is thawed.

The ice nucleus generator (13) is provided with a subcooling heat exchanger (5).
0) is attached to the water pipe (35) at the downstream side, and a part of the water flowing through the water pipe (35) is cooled and iced by the refrigerant in the refrigerant circuit (20), and it is supercooled as ice nuclei. It is configured to supply the solution to the cancellation section (34).

The mixer (33) and the subcooling eliminating section (34)
Each is constituted by a hollow cylindrical container, and is configured such that water introduced in a tangential direction forms a swirling flow. And
The mixer (33) stirs the water and ice heated by the preheater (11) to promote the melting of the ice, while the supercooling elimination unit (34)
Is the ice nucleus generated by the ice nucleator (13) and the supercooled heat exchanger
The supercooling water generated in (50) is stirred to eliminate the supercooling.

Next, the supercooling heat exchanger (50) will be described.

As shown in FIG. 3, the subcooling heat exchanger (50)
Is provided with a closed cylindrical container (51) having an axis extending vertically. Inside the container (51), at the upper and lower ends thereof, an upper water circulation portion (53a) defined by the upper end of the container (51) and the upper tube sheet (52a), and the lower side of the container (51) Lower water flow section defined by the end and lower tube sheet (52b)
(53b). Further, in the container (51), a plurality of heat transfer tubes (60) extending vertically and communicating between the upper water circulation part (53a) and the lower water circulation part (53b) are provided.

As shown in FIG. 4, each of the heat transfer tubes (60) is arranged parallel to each other with a certain interval between adjacent heat transfer tubes (60). One end of each heat transfer tube (60) is connected to the upper water flow section (5
3a), and the other end is in communication with the lower water circulation part (53b), allowing water to flow between the upper water circulation part (53a) and the lower water circulation part (53b). I have. Also, the heat transfer tube in the container (51)
In the outer space of (60), the upper tube sheet (52a) and the lower tube sheet (52b)
And a refrigerant flow section (54) partitioned between the two.

The refrigerant flow section (54) communicates with a lower connection pipe (56) for introducing refrigerant at a lower part of the container (51), and communicates with an upper connection pipe (55) for discharging refrigerant at an upper part of the container (51). Communicating.

-Heat Transfer Tube- Next, the heat transfer tube (60) which is a feature of the present invention will be described in detail.

As shown in FIG. 5, a plurality of fins (57) are formed on the outer wall of the heat transfer tube (60) at regular intervals in the axial direction of the tube. The fins (57) increase the tube outer area of the heat transfer tube and improve the heat exchange efficiency. This heat transfer tube (6
The material of (0) is copper, but aluminum can also be used.

On the other hand, inside the heat transfer tube (60), a water flow path (8
A resin rod (80) is inserted as a flow path forming body forming 1). The resin rod (80) is formed to have a length substantially matching the axial length of the heat transfer tube. The resin rod (80) has a plurality of spiral ridges (83) projecting outward in the radial direction of the pipe, and the rod-shaped body (82a).
And are formed integrally with the second member. And resin rod
(80) is an epoxy resin, polyamide 6, polyamide 66,
It is made of a material such as polyacetal.

The rod-like body (82a) has a hollow cylindrical shape coaxial with the tube axis of the heat transfer tube (60), and is located in the upper water flow part (53a) and the lower water flow part (53b). The upper and lower ends of the rod-shaped body (82a) are sealed so that water does not flow into the center (89) of the rod-shaped body (82a).

The inclination angle of the spiral ridge (83) with respect to the axis is set to be substantially the same so as to keep a constant pitch with respect to the axial direction. However, the spiral ridge (83) may be configured to have a different pitch and a different angle depending on various design conditions.

The spiral ridge (83) winds the outer peripheral surface of the rod (82a) so that the water flow (W) spirals in the axial direction around the rod (82a). In the present embodiment, eight spiral ridges (83) are formed, and the eight spiral ridges form eight independent flow paths.

Then, as shown in FIG. 6, the spiral ridge (83)
In the cross-section of the flow path, the thickness (t) gradually decreases in the direction from the rod-shaped body (82a) to the inner peripheral surface of the heat transfer tube (60), and the thickness once becomes the minimum (t-min). After that, at the tip (near the portion where the spiral ridge (83) and the inner peripheral surface of the heat transfer tube (60) are in contact) (88), the tip (88) and the inner peripheral surface of the heat transfer tube (60) It has a structure whose thickness is sharply increased so as not to make a corner at the corner.

That is, the tip (88) is formed in a so-called divergent shape, and forms a corner between the spiral ridge (83) and the inner peripheral surface of the heat transfer tube (60). Are formed on a circular surface (C11) having a predetermined roundness. And, by the arc surface (C11), the tip end portion (88) smoothly continues to the inner peripheral surface of the heat transfer tube (60). In addition, arc surface (C11)
Is formed in an arc shape such that the whole water swirls in the flow path so that the flow of water does not stagnate at the corners.

-Operation- Next, the operation of the above-described regenerative air conditioner (10) will be described. First, a cold storage operation using the supercooling heat exchanger (50) will be described.

-Cold heat storage operation- In this operation mode, as shown in FIG.
2) is switched to the solid line side, and the heat storage electric expansion valve (EV-3) is adjusted to a predetermined opening degree, while the other electric expansion valves (EV-1, EV-2) are adjusted.
To close. Also, the first and second solenoid valves (SV-1 and SV-2)
Is open, and the third solenoid valve (SV-3) is closed.

In this state, in the refrigerant circuit (20), the refrigerant discharged from the compressor (21) exchanges heat with the outside air in the outdoor heat exchanger (23) as shown by the arrow in FIG. I do. After that, this refrigerant is decompressed by the heat storage electric expansion valve (EV-3), and then exchanges heat with water in the supercooling heat exchanger (50) to evaporate.
The water is cooled to a supercooled state (eg -2 ° C). Thereafter, the refrigerant passes through the accumulator (25) and the compressor (21)
Inhaled.

In this operation, part of the refrigerant is
After being diverted from the downstream side of the heat storage electric expansion valve (EV-3) to the ice nucleus circuit (2b), the pressure was reduced by the capillary tube (CP), and then evaporated by the ice nucleus generator (13), and the accumulator (25) was removed. Via compressor
Inhaled in (21). In this ice nucleus generator (13), the refrigerant exchanges heat with the water flowing through the water pipe (35), and the ice blocks are removed from the water pipe (3).
Generated on the inner wall of 5).

On the other hand, in the water circulation circuit (30), water is circulated by driving the pump (32). The water flowing out of the heat storage tank is heated by a preheater (11) via a pump (32), and then stirred by a mixer (33). Thereafter, the water is cooled by a heat exchanger with the refrigerant in the subcooling heat exchanger (50), is cooled to a predetermined supercooled state, and flows out of the supercooling heat exchanger (50). Then, the supercooled water flowing out of the heat exchanger (50) is further cooled in the ice nucleus generator (13), and the ice block is cooled by a water pipe (35).
Generated on the inner wall surface. After that, ice nuclei are generated around the ice block, and the supercooled water containing the ice nuclei
4) supplied to. Then, in the supercooling elimination section (34),
The ice nuclei and the supercooled water are stirred, and slurry-like ice for heat storage is generated and collected and stored in the heat storage tank (31).

At the time of the main operation, a relatively high-temperature refrigerant flows through the preheater (11), and even if ice flows through the water pipe (35), the preheater (1) may be used.
In step (1), the mixture is heated and melted, and ice is prevented from entering the supercooled heat exchanger (50).

Next, the flow of the refrigerant and water in the subcooling heat exchanger (50) will be described.

The refrigerant flows from the lower connection pipe (56) to the refrigerant flow section (54).
While absorbing heat from the water flowing in the heat transfer tube (60), and flows upward through the refrigerant flow section (54) while forming a gas-liquid interface (G). Then, the refrigerant that has completed heat exchange with water flows out of the upper connection pipe (55).

On the other hand, the water that has flowed into the flow path (81) from the lower water flow section (53b) exchanges heat with the low-temperature refrigerant flowing through the refrigerant flow section (54), and is cooled. It flows upward through (81). In other words, the water flowing from the lower water circulation part (53b) at a temperature higher than the freezing point gradually lowers the temperature in the downstream direction of the flow path (81), that is, upward of the heat transfer tube (60),
Eventually, it enters a supercooled state, and flows out of the upper water outflow portion (53a) while maintaining a predetermined degree of supercooling.

Water is supplied to the inner peripheral surface of the heat transfer tube (60),
Flows in eight spiral spaces defined by the outer peripheral surface of the spiral projection and the surface of the spiral ridge (83). Therefore, the main flow of water flows from the bottom to the top of the heat transfer tube (60).
It flows spirally in the axial direction of (60). Therefore, in the cross section of the flow path, a swirling flow (F1) around the center of the flow path is generated.

As described above, the cold storage operation using the supercooling heat exchanger (50) is performed.

Next, another operation of the regenerative air conditioner (10) will be schematically described.

-Normal Cooling Operation- In this operation mode, only the refrigerant circuit (20) is operated, and the water circuit (30) is not operated.

In this operation mode, the four-way switching valve (22) is switched to the solid line side in FIG. 1, the indoor electric expansion valve (EV-2) is superheated, and the outdoor electric expansion valve (EV-1) is operated. The heat storage electric expansion valve (EV-3) is controlled to a fully closed state and to a fully closed state. On the other hand, each solenoid valve (SV-1, SV-2, SV-3) is closed.

In this state, the refrigerant discharged from the compressor (21) exchanges heat with the outside air in the outdoor heat exchanger (23) and condenses. After that, the refrigerant is decompressed by the indoor electric expansion valve (EV-2), and then evaporates in the indoor heat exchanger (24) to produce an accumulator.
After (25), the process returns to the compressor (21). By this circulation operation,
The regenerative air conditioner (10) cools the room.

-Cooling operation utilizing cold storage- In this operation mode, as shown in FIG.
2) is switched to the solid line side, the indoor electric expansion valve (EV-2) is controlled to a predetermined opening, and the other electric expansion valves (EV-1 and EV-3) are fully opened. Further, the first and third solenoid valves (SV-1 and SV-3) are opened, and the second solenoid valve (SV-2) is closed.

In this state, in the water circulation circuit (30),
The pump (32) is driven to circulate cold water. The cold water in the heat storage tank (31) passes through the pump (32), the preheater (11), and the mixer (33) in this order, and then flows into the supercooling heat exchanger (50). At this time, the cold water is not preheated by the preheater (11), but simply passes through the preheater (11). Then, the cold water flowing into the subcooling heat exchanger (50) exchanges heat with the refrigerant and is heated. Thereafter, the heated water flows out of the subcooling heat exchanger, and returns to the heat storage tank (31) via the subcooling elimination section. Then, the heated water is cooled by exchanging heat with ice stored in the heat storage tank (31), and becomes cold water,
It flows out of the heat storage tank (31) again and circulates in the water circulation circuit.

On the other hand, in the refrigerant circulation circuit (20), a part of the refrigerant discharged from the compressor (21) passes through the four-way switching valve (22) as shown by the arrow in FIG. Heat exchanger (2
It flows to 3) and exchanges heat with the outside air in the outdoor heat exchanger (23) to condense. Further, the other discharged refrigerant flows into the supercooling heat exchanger (50) via the hot gas passage (2C), and exchanges heat with cold water circulating in the water circulation circuit (30) to condense. Then, the refrigerant condensed in the outdoor heat exchanger (23) and the subcooling heat exchanger (50) are merged and decompressed by the indoor electric expansion valve (EV-2), and then the indoor heat exchanger (24) After evaporating and cooling the room air, the air is sucked into the compressor (21) through the accumulator (25).

By the above operation, the indoor cooling operation using the cold heat of the ice stored in the heat storage tank (31) is performed.

-Normal Heating Operation- In this operation mode, the water circulation circuit (30) is not operated, and only the refrigerant circulation circuit (20) is operated.

In this operation mode, the four-way switching valve (22) is switched to the broken line side in FIG. 1, the outdoor electric expansion valve (EV-1) is controlled to a predetermined opening, and the indoor electric expansion valve (EV-2) is controlled. Is fully opened, and the heat storage electric expansion valve (EV-3) is controlled to be fully closed. On the other hand, each solenoid valve
(SV-1, SV-2, SV-3) are all closed.

In this state, the refrigerant discharged from the compressor (21) flows to the indoor heat exchanger (24), exchanges heat with the indoor air, condenses, and heats the indoor air. After that, this refrigerant is decompressed by the outdoor electric expansion valve (EV-1),
In (23), heat exchange with the outside air evaporates. Thereafter, the refrigerant is sucked into the compressor (21) via the accumulator (25). The room is heated by such a circulation operation of the refrigerant.

The operation of the regenerative air conditioner (10) has been described above.

As described above, in the supercooling heat exchanger (50), the inner peripheral surface of the heat transfer tube (60) intersects with the surface of the spiral ridge (83) due to the above structure of the tip portion (88). Arc surface at corner (C11)
Are formed. Therefore, this corner has not a corner but a radius. Therefore, this arc surface (C
11) There is no secondary flow in the vicinity. Also, rod-shaped body (82a)
The corner formed at the intersection of the outer peripheral surface of the helical ridge (83) and the surface of the spiral ridge (83) is not an acute angle, but an obtuse angle.

Therefore, the flow of water in the cross section of the flow path is only the swirling flow (F1). As a result, the water cooled near the arc surface (C11) is transported to other parts by the swirling flow (F1),
Mix well with the other part of the water. Thus, the arc surface
The water to be cooled near (C11) is constantly exchanged, so that the water is not extremely cooled near the arc surface (C11) as compared with other parts. Therefore, the temperature distribution of water becomes uniform in the cross section of the flow path.

As described above, supercooled water is inherently unstable, and even with a slight stimulus, the supercooled state is eliminated and icing starts. Further, the uneven temperature distribution of the supercooled water in the cross section of the flow path also causes the supercooling to be eliminated. However, in the subcooling heat exchanger (50), there is no unevenness of the temperature distribution in the cross section of the flow channel which causes the supercooling state to be eliminated, so that a flow maintaining a stable supercooling state can be realized.

Therefore, even if the degree of supercooling of the water is considerably large, blockage of the flow path due to icing of the supercooled water does not easily occur.
Therefore, the risk of blockage of the flow path due to icing is significantly reduced, and the risk of rupture of the heat transfer tube (60) is low, so that the degree of supercooling of the water flowing through the flow path (81) is increased more than before. This makes it possible to reduce the size and increase the efficiency of the heat exchanger.

In the present embodiment, since the rod-shaped body (82a) has a hollow cylindrical shape, even if the supercooled water in the flow passage is frozen due to any accident, the rod-shaped body (82a) is deformed inside. The rupture of the heat pipe (60) can be prevented.

[0072]

Second Embodiment The heat exchanger of the second embodiment differs from the heat exchanger of the first embodiment only in the internal structure of the heat transfer tube, and the other parts are the same as the heat exchanger of the first embodiment. . Therefore, description of other parts is omitted.

As shown in FIG. 9, in the heat exchanger of the second embodiment, a resin rod (80b) for forming a water flow path is inserted inside a heat transfer tube (60b). The resin rod (80b) is connected to the heat transfer tube (6
0b), and a plurality of radially outwardly projecting spiral ridges (83b) of the heat transfer tube (80b) are integrally formed with the rod (82b). Is formed. The resin rod (80) is made of a material such as epoxy resin, polyamide 6, polyamide 66, and polyacetal. The rod-shaped body (82b) has a hollow cylindrical shape coaxial with the tube axis of the heat transfer tube (60b), and is disposed in the upper water circulation part (53a) and the lower water circulation part (53b). The upper and lower ends of 82b) are sealed so that water does not flow into the center (89b) of the rod-shaped body (82b).

The spiral ridge (83b) winds the outer peripheral surface of the rod (82b) so that the water flow (W) spirals in the axial direction around the rod (82a). Also, spiral ridges (83
b) is formed with eight, and the eight spiral ridges form eight independent flow paths.

As shown in FIG. 9, the spiral ridge (83b) is smoothly continuous with the rod-like body (82b) in the cross section of the flow path, and the inner peripheral surface of the heat-transfer tube (60b) extends from the rod-like body (82b). After gradually decreasing its thickness in the direction toward, the thickness once becomes minimum and then at the tip (88b), the tip (88
The structure is such that the thickness is sharply increased so as not to form a corner at the corner between b) and the inner peripheral surface of the heat transfer tube (60b).

That is, an arc surface (C22) having a predetermined roundness is formed at the corner between the rod-shaped body (82b) and the spiral ridge (83b). The tip (88b) is formed in a so-called divergent shape, and forms a corner between the spiral ridge (83b) and the inner peripheral surface of the heat transfer tube (60b). It is formed on a rounded arc surface (C21). And, by the arc surface (C21), the tip portion (88b) smoothly continues to the inner peripheral surface of the heat transfer tube (60b). In addition, arc surface (C22)
The arc surface (C11) is formed in an arc shape such that the entire water swirls in the flow channel so that the flow of water does not stagnate at the corners.

With the above structure, in the heat exchanger according to the second embodiment, secondary heat which may be generated at a corner where the inner peripheral surface of the heat transfer tube (60b) intersects with the surface of the spiral ridge (83b) is provided. Not only the flow, but also a secondary flow that may occur at a corner where the rod-shaped body (82b) and the spiral ridge (83b) intersect can be suppressed. Therefore, the water flowing in the flow path
There is only 2), and no secondary flow that causes overcooling is eliminated.

Therefore, for the same reason as described in the first embodiment, the supercooled state of the water flowing in the flow path can be further stabilized. As a result, the risk of blockage of the flow path due to icing is significantly reduced, and the risk of rupture of the heat transfer tube (60b) is low, so the degree of supercooling of the water flowing through the heat exchanger is increased more than before. This makes it possible to reduce the size and increase the efficiency of the heat exchanger.

[0079]

Third Embodiment The heat exchanger of the third embodiment differs from the heat exchanger of the first embodiment only in the internal structure of the heat transfer tube.
Other parts are the same as the heat exchanger of the first embodiment. As shown in FIG. 10, in the heat exchanger of the present embodiment, the heat transfer tubes
On the inner surface of (60c), the flow of water flowing through the pipe is
A plurality of spiral ridges (83c) that spirally rotate in the axial direction around c) are formed so as to extend toward the center of the tube. Then, the inner peripheral surface of the heat transfer tube (60c),
c) and the surface of the spiral ridge (83c)
A water flow path spiraling in the axial direction of c) is formed. The spiral ridge (83c) smoothly continues to the inner peripheral surface of the heat transfer tube (60c) in a cross section orthogonal to the water flow direction, and
0c) in the direction from the inner peripheral surface to the outer peripheral surface of the rod-shaped body (82c), the thickness (t ') is rapidly reduced to a minimum (t'-
min), gradually increasing its thickness (t '), and further at the tip (the vicinity of the portion where the spiral ridge (83c) and the outer peripheral surface of the rod-shaped body (82c) are in contact) (88c) The thickness is sharply increased so that no corner is formed at the corner between the tip (88c) and the inner peripheral surface of the rod (82c). That is, an arc surface (C31) having a predetermined roundness is formed at the corner between the inner peripheral surface of the heat transfer tube (60c) and the spiral ridge (83c). The tip (88c) is formed in a so-called divergent shape, and forms a corner between the spiral ridge (83b) and the outer peripheral surface of the rod-shaped body (82c). Arc surface with
(C32). And, by the arc surface (C32), the tip portion (88c) smoothly continues to the outer peripheral surface of the rod-shaped body (82c). In addition, arc surface (C31) and arc surface (C
32) is formed in an arc shape such that the entire water swirls in the flow channel so that the flow of water does not stagnate at the corners.

The resin rod (82c) has a cylindrical shape coaxial with the tube axis of the heat transfer tube (60c), and the resin rod (82c) is located in the upper water flow part (53a) and the lower water flow part (53b). The upper and lower ends of the rod (82c) are sealed so that water does not flow into the center (89c) of the resin rod (82c).

The inclination angle of the spiral ridge (83c) with respect to the axis is
The angles are set to be substantially the same so as to keep a constant pitch with respect to the axial direction. However, depending on various design conditions, the spiral ridge may be configured to have a different pitch and a different angle.

With the above structure, in the heat exchanger of the third embodiment, there is a possibility that the heat generated at the corner where the inner peripheral surface of the heat transfer tube (60c) intersects with the surface of the spiral ridge (83b). Next flow,
In addition, it is possible to suppress a secondary flow that may occur at a corner where the rod-shaped body (82c) and the spiral ridge (83c) intersect. Therefore, only the swirling flow (F3) flows in the flow path, and no secondary flow that causes the supercooling to be eliminated is generated.

Therefore, for the same reason as described in the first embodiment, the supercooled state of the water flowing in the flow path can be further stabilized. As a result, the risk of blockage of the flow channel due to icing is significantly reduced, and the risk of rupture of the heat transfer tube (60c) is low, so the degree of supercooling of the water flowing through the heat exchanger is increased more than before. This makes it possible to reduce the size and increase the efficiency of the heat exchanger.

[0084]

As described above, according to the present invention, in the cross section perpendicular to the flow direction of the flow path of the heat storage medium (flow path cross section), the inner peripheral surface of the heat transfer tube (60, 60b, 60c) is Ridge (83,83b, 83
Arc surfaces (C11, C21, C31) are formed at the corners where the surface of (c) intersects, and the outer peripheral surfaces of the rods (82a, 83b, 83c) and the spiral ridges (83, 8) are formed.
No secondary flow occurs since there is no sharp corner at the corner where the surface intersects with the surface of 3b, 83c). This makes it difficult to eliminate the supercooled state of the heat storage medium caused by the secondary flow, so that heat exchange between the heat storage medium and the refrigerant can be performed while maintaining the supercooled state of the heat storage medium stably. Therefore, it is possible to prevent the passage of the heat storage medium from being clogged due to icing of the heat storage medium that occurs when the supercooled state is resolved, even if the degree of supercooling of the heat storage medium is considerably large. As a result, the risk of blockage of the flow path due to icing is significantly reduced, and the risk of rupture of the heat transfer tubes (60, 60b, 60c) is low. It is possible to increase the heat exchanger more than before, and it is possible to reduce the size and increase the efficiency of the heat exchanger. Furthermore, the performance of the entire heat storage type air conditioner can be improved by downsizing and increasing the efficiency of the heat exchanger.

[Brief description of the drawings]

FIG. 1 is a diagram showing a refrigerant circuit and a water circuit.

FIG. 2 is a diagram showing a water circulation circuit.

FIG. 3 is a side view of the heat exchanger according to the embodiment of the present invention.

FIG. 4 is a sectional view of the subcooling heat exchanger at a position corresponding to line VV in FIG. 3;

FIG. 5 is a view showing a heat transfer tube of the heat exchanger according to the embodiment of the present invention.

FIGS. 6A and 6B are diagrams showing an internal structure of a heat transfer tube according to the heat exchanger of Embodiment 1, in which FIG. 6A is a diagram showing the entire internal structure, and FIG. 6B is a diagram in which a part of the internal structure is enlarged. It is.

FIG. 7 is a diagram showing a refrigerant circulation circuit and a water circulation circuit during a cold storage operation.

FIG. 8 is a diagram showing a refrigerant circulation circuit and a water circulation circuit during a cooling operation using cold storage heat.

FIG. 9 is a view corresponding to FIG. 6 of the heat exchanger according to the second embodiment.

FIG. 10 is a view corresponding to FIG. 6 of a heat exchanger according to a third embodiment.

FIG. 11 is a view corresponding to FIG. 6 of a conventional heat exchanger.

[Explanation of symbols]

 48 Container 50 Subcooling heat exchanger 60, 60b, 60c Heat transfer tube 80 Resin rod 81 Flow path 82a, 82b, 82c Rod 83, 83b, 83c Spiral ridge 88,88b, 88c Tip 89,89c Hollow C11, C21, C22, C31, C32 Arc surface F1, F2, F3 Swirling flow

Claims (4)

[Claims] 1. A closed container (51), and a plurality of heat transfer tubes (60, 60b, 60c) provided in the closed container (51), wherein the heat transfer tubes (60, 60b, 60c) are provided. Refrigerant (R) flowing outside the heat transfer tube (6)
0,60b, 60c), the shell and tube type heat exchanger that exchanges heat with the heat storage medium (W) flowing inside the heat transfer tubes (60,60b, 60c). The rods (82a, 82b, 82c) inserted into the rods (82a, 82b, 82c)
Helical ridges (83, 83) located between the outer peripheral surface of the heat transfer tubes (60, 60b, 60c) to form a helical flow path of the heat storage medium
b, 83c) are provided, and a corner of the heat transfer tube (60, 60b, 60c) and the spiral ridge (83, 83b, 83c) is formed in an arcuate surface. Tube type heat exchanger. 2. The shell-and-tube heat exchanger according to claim 1, further comprising: said rod-shaped body (82b, 82c) and said spiral ridge (83b, 83c).
The shell and tube type heat exchanger characterized in that the corner of the shell and tube is formed in an arc surface. 3. The shell and tube heat exchanger according to claim 1, wherein the rod-shaped body (82a, 82b) and the spiral ridge (83, 83b) are integrally formed. A shell and tube heat exchanger. 4. The shell and tube heat exchanger according to claim 1, wherein the heat transfer tube (60c) and the spiral ridge (83c) are integrally formed. Features shell and tube heat exchanger.