AU2017442329B2

AU2017442329B2 - Heat exchanger, refrigeration cycle apparatus and method of manufacturing heat exchanger

Info

Publication number: AU2017442329B2
Application number: AU2017442329A
Authority: AU
Inventors: Kensaku HATANAKA; Takahiko Kawai; Toru Koide; Kenta MURATA; Toshiaki Ota
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2017-12-06
Filing date: 2017-12-06
Publication date: 2021-07-15
Anticipated expiration: 2037-12-06
Also published as: EP3722729B1; JPWO2019111349A1; ES2882218T3; EP3722729A1; WO2019111349A1; AU2017442329A1; EP3722729A4; SG11202004978QA

Abstract

A heat exchanger relating to the present invention has: a first pipe, in which a first heat medium flows; and a second pipe, which is wound around the first pipe, and in which a second heat medium flows. The first pipe has, on the inner surface thereof, a plurality of protrusions, which are formed in spiral lines in the direction in which the first heat medium flows in the first pipe, and the protrusions formed in each line are disposed at unequal intervals.

Description

DESCRIPTION

Title of Invention HEAT EXCHANGER, REFRIGERATION CYCLE APPARATUS AND METHOD OF

MANUFACTURING HEAT EXCHANGER

Technical Field

[0001]

The present disclosure relates to a heat exchanger including a first tube

and a second tube wound around the first tube, a refrigeration cycle apparatus

including the heat exchanger, and a method of manufacturing the heat

exchanger.

Background Art

[0002]

Conventionally, there has been a heat exchanger including a first tube in which a

path through which a first heat medium flows is formed, and a second tube in which a

path through which a second heat medium flows is formed, the second tube being

wound around the outer periphery of the first tube. In such a heat exchanger, heat is

exchanged between the first heat medium flowing in the first tube and the second heat

medium flowing in the second tube. The first tube may be called a core tube. The

second tube may be called an external tube. One example of the first heat medium is

water or antifreeze. One example of the second heat medium is refrigerant.

[0003]

As such a heat exchanger, as described in Patent Literature 1, there has been

proposed "a heat exchanger including a core tube having a plurality of protrusions on

the inside of the core tube, formed by pressing the outside of the core tube, and a

winding tube wound around the outside of the core tube".

[0004]

The heat exchanger of Patent Literature 1 includes the core tube having the

plurality of protrusions on the inside of the core tube, formed by pressing the outside of

the core tube. By making the core tube in such a manner, in the heat exchanger of

Patent Literature 1, a flow of the first heat medium flowing in the core tube is agitated by

the protrusions, thereby improving a heat exchange performance between water as the

first heat medium flowing in the core tube and refrigerant as the second heat medium

flowing in the winding tube.

Citation List Patent Literature

[0005] Patent Literature 1: Japanese Unexamined Patent Application Publication No.

2006-317114

Summary of Invention

Technical Problem

[0006]

In the heat exchanger of Patent Literature 1, when forming the plurality of

protrusions on the inside of the core tube by pressing the outside of the core tube, as a

method of forming the plurality of protrusions, a gearwheel-like jig is used, and teeth

parts of the gearwheel-like jig are pressed against the outside of the core tube to form

the inside protrusions in a spiral manner. In the following description, the gearwheel

like jig is simply referred to as the jig. Moreover, for a further improvement of the heat

exchange performance by adding the protrusions, it is possible to provide a large

number of inside protrusions in a spiral direction with the use of a plurality of jigs. The

plurality of protrusions are provided by independently operating each of the plurality of

jigs.

[0007]

In the case where the protrusions are formed by the plurality of jigs, the positional

relationship between the protrusions to be added by the respective gearwheels is

determined by the phase difference between the respective gearwheels. Depending

on the phase difference between the respective jigs, the protrusions to be added by one

jig and the protrusions to be added by other jig may be aligned with each other in a tube

axis direction. A flow of the first heat medium is agitated by the protrusions provided

on an upstream side of the flow of the first heat medium, thereby improving the heat exchange performance. On the other hand, at the protrusions provided on a downstream side of the flow of the first heat medium, the flow rate is reduced, the agitation effect is decreased, and the effect of improving the heat exchange performance by the protrusions is decreased.

[0008] Considering the above problem in the background, it is desirable to provide a

heat exchanger configured to improve the heat exchange performance by avoiding a

decrease in the agitation effect of the plurality of protrusions, a refrigeration cycle

apparatus including the heat exchanger, and a method of manufacturing the heat

exchanger.

Solution to Problem

[0009]

[0010] A heat exchanger of an embodiment of the present disclosure includes: a

first tube through which a first heat medium flows; and a second tube through which

a second heat medium flows, the second tube being wound around the first tube, the

first tube having a plurality of protrusions protruding inside of the first tube, the

plurality of protrusions being provided in a plurality of streaks being provided in a

spiral manner in a direction to which the first heat medium of the first path flows in

the first tube, one streak of the plurality of streaks including the plurality of

protrusions each being arranged at unequal spacing intervals.

In another embodiment, the present disclosure provides a method of

manufacturing a heat exchanger includes a first tube in which a first path through which

a first heat medium flows is formed, and a second tube in which a second path through

which a second heat medium flows is formed, the second tube being wound around the

first tube. The method comprises providing a plurality of protrusions protruding inside of

the first tube in a plurality of streaks in a spiral manner by pressing an outside of the first

tube using a plurality of jigs each having a gearwheel on which a plurality of protruding

parts are provided, wherein, in each of the jigs, the plurality of protruding parts are

arranged at unequal spacing intervals on the gearwheel to provide each of the plurality

of protrusions at unequal spacing intervals.

Advantageous Effects of Invention

[0011]

According to the heat exchanger of the embodiment of the present disclosure, in a projection in which the first tube is projected in the tube axis direction, adjacent

protrusions do not overlap, and therefore the flow rate is not reduced even at the

protrusions provided on the downstream side of the flow of the first heat medium, and

the heat exchange performance is improved.

Brief Description of Drawings

[0012]

[Fig. 1] Fig. 1 is a schematic configuration diagram schematically illustrating an

example of a circuit configuration of a refrigeration cycle apparatus including a heat

exchanger according to Embodiment 1 of the present disclosure.

[Fig. 2] Fig. 2 is a perspective diagram schematically illustrating a configuration of

the heat exchanger according to Embodiment 1 of the present disclosure.

[Fig. 3] Fig. 3 is an explanatory diagram for explaining an example of providing

protrusions on a first tube of the heat exchanger according to Embodiment 1 of the

present disclosure.

[Fig. 4] Fig. 4 is an explanatory diagram for explaining a conventional example of

providing protrusions on the first tube as a comparative example.

[Fig. 5] Fig. 5 is an explanatory diagram for explaining the first tube having the

protrusions provided by the method of Fig. 3.

[Fig. 6] Fig. 6 is an explanatory diagram for explaining the first tube having the

protrusions provided by the method of Fig. 4.

[Fig. 7] Fig. 7 is an explanatory diagram for explaining other example of providing

protrusions on the first tube according to Embodiment 1 of the present disclosure.

[Fig. 8] Fig. 8 is an explanatory diagram for explaining the spacing interval of the

protrusions of the first tube of the heat exchanger according to Embodiment 1 of the

present disclosure.

[Fig. 9] Fig. 9 is an explanatory diagram for explaining the spacing interval of the

present disclosure.

[Fig. 10] Fig. 10 is an explanatory diagram for explaining a shape of the first tube

of the heat exchanger according to Embodiment 2 of the present disclosure.

[Fig. 11] Fig. 11 is an explanatory diagram for explaining a shape of the first tube

of the heat exchanger according to Embodiment 3 of the present disclosure.

Description of Embodiments

[0013] Embodiments of the present disclosure will be described hereinafter with

reference to the drawings as appropriate. In the following drawings including Fig. 1, the relationship in size among component parts may be different from the actual

relationship. In the following drawings including Fig. 1, the component parts labelled

with the same reference signs are the same component parts or equivalent, and the

same can be said for the entire description. Moreover, the forms of the components

stated in the full description are merely examples, and not what limits the scope of

matters in present disclosure.

[0014]

Embodiment 1

Fig. 1 is a schematic configuration diagram schematically illustrating an example

of a circuit configuration of a refrigeration cycle apparatus 200 including a heat

exchanger 100 according to Embodiment 1 of the present disclosure. The refrigeration

cycle apparatus 200 will be described with reference to Fig. 1.

In Embodiment 1, the description is given on an assumption that a first heat

medium is water, and a second heat medium is refrigerant.

[0015]

[Overall Configuration of Refrigeration Cycle Apparatus 200]

The refrigeration cycle apparatus 200 has a refrigerant circuit Al, and a heat

medium circuit A2. The refrigerant circuit Al and the heat medium circuit A2 are

thermally connected through the heat exchanger 100. The heat medium circuit A2 is also connected to a water supply circuit A3 through a hot water storage tank 207. The water supply circuit A3 is connected to a hot water supply utility unit U, and configured to supply hot water to the hot water supply utility unit U. Examples of the hot water supply utility unit U include at least one of various loads that require hot water, such as a faucet and a bath of a household. The water supply circuit A3 is connected to a water pipe or other pipe, and is configured to be able to supply water.

[0016] Refrigerant circulates in the refrigerant circuit Al through a refrigerant tube 20A.

Carbon dioxide can be used as the refrigerant. The refrigerant circuit Al is configured

to include a compressor 201 for compressing the refrigerant, the heat exchanger 100

functioning as a condenser, an expansion device 202, and a heat exchanger 203

functioning as an evaporator.

[0017]

The compressor 201 compresses the refrigerant. The refrigerant compressed

by the compressor 201 is discharged from the compressor 201 and sent to the heat

exchanger 100. The compressor 201 can be made of, for example, a rotary

compressor, a scroll compressor, a screw compressor, or a reciprocating compressor.

[0018] The heat exchanger 100 functions as a condenser, exchanges heat between

high-temperature, high-pressure refrigerant flowing in the refrigerant circuit Al and

water flowing in the heat medium circuit A2, heats the water, and condenses the

refrigerant. The heat exchanger 100 is a water-refrigerant heat exchanger that

exchanges heat between water and refrigerant. The heat exchanger will be described

in detail later.

The heat exchanger 100 is an equivalent of a heat exchanger of the present

disclosure.

[0019]

The expansion device 202 expands the refrigerant flowing out of the heat

exchanger 100 and reduces the pressure. The expansion device 202 maybe made of, for example, an electric expansion valve capable of adjusting the flow rate of the refrigerant. As the expansion device 202, not only the electric expansion valve, but also a mechanical expansion valve using a diaphragm for a pressure receiving part, a capillary tube or the like is applicable.

[0020]

The heat exchanger 203 functions as an evaporator, exchanges heat between

low-temperature, low-pressure refrigerant discharged from the expansion device 202

and air supplied by a fan 203A attached to the heat exchanger 203, and evaporates

low-temperature, low-pressure liquid refrigerant or two-phase refrigerant. The heat

exchanger 203 can be made of, for example, a fin-and-tube type heat exchanger, a

micro channel heat exchanger, or a heat pipe type heat exchanger.

[0021]

The water circulates in the heat medium circuit A2 through a heat medium tube

A. The heat medium circuit A2 is configured to include the heat exchanger 100 and

a pump 205 for conveying the water.

[0022]

Moreover, the refrigeration cycle apparatus 200 includes a controller 60 for

generally controlling the entire refrigeration cycle apparatus 200. The controller 60

controls a driving frequency of the compressor 201. Further, the controller 60 controls

the opening degree of the expansion device 202, according to the operation state.

Furthermore, the controller 60 controls driving of the fan 203A and the pump 205. That

is, based on an operation instruction, the controller 60 uses information sent from each

of temperature sensors (not shown) and each of pressure sensors (not shown), and

controls actuators of the compressor 201, the expansion device 202, the fan 203A, the

pump 205, etc.

[0023]

Each of functional units included in the controller 60 is made of dedicated

hardware, or a micro processing unit (MPU) for executing a program stored in a

memory.

[0024]

[Configuration of Heat Exchanger 100]

Fig. 2 is a perspective diagram schematically illustrating the configuration of the

heat exchanger 100.

The heat exchanger 100 has a first tube 1 in which a first path FP1 through which

water as the first heat medium flows, and a second tube 2 in which a second path FP2

through which refrigerant as the second heat medium flows is formed. The second

tube 2 is wound in one turn or a plurality of turns around the outer periphery of the first

tube 1 and in contact with the first tube 1. The first tube 1 makes a part of the heat

medium tube 10A. The second tube 2 makes a part of the refrigerant tube 20A.

[0025]

In the first tube 1, a water inlet 1a and a water outlet 1b communicating with the

first path FP1 are provided. In the second tube 2, a refrigerant inlet 2a and a

refrigerant outlet 2b communicating with the second path FP2 are provided.

The heat exchanger 100 can be connected to the refrigerant circuit Al and the

heat medium circuit A2 such that the direction of the water flowing through the first tube

1 and the direction of the refrigerant flowing through the second tube 2 are opposite.

Hence, the heat exchange efficiency between the heat medium and the refrigerant is

improved.

[0026]

[Operation of Refrigeration Cycle Apparatus 200]

Here, returning to Fig. 1, an operation of the refrigeration cycle apparatus 200 will

be described.

The refrigeration cycle apparatus 200 can perform a hot water supply operation,

based on an instruction from the load side.

The operations of the actuators are controlled by the controller 60.

[0027]

The low-temperature, low-pressure refrigerant is compressed by the compressor

201 to be high-temperature, high-pressure gas refrigerant, and is discharged from the

compressor 201. The high-temperature, high-pressure gas refrigerant discharged from

the compressor 201 flows into the heat exchanger 100. The refrigerant that has flowed

into the heat exchanger 100 circulates in the second tube 2, and exchanges heat with the water flowing in the first tube 1. At this time, the refrigerant is condensed to be low temperature, high-pressure liquid refrigerant, and flows out of the heat exchanger 100.

In the case where carbon dioxide is used as the refrigerant, the refrigerant undergoes a

temperature change while in a supercritical state.

On the other hand, the water that has flowed into the first tube 1 is heated by the

refrigerant flowing in the second tube 2, and is supplied to the load side.

[0028]

The low-temperature, high-pressure liquid refrigerant flowing out of the heat

exchanger 100 is made low-temperature, low-pressure liquid refrigerant or two-phase

refrigerant by the expansion device 202, and flows into the heat exchanger 203. The

refrigerant that has flowed into the heat exchanger 203 exchanges heat with the air

supplied by the fan 203A attached to the heat exchanger 203, becomes low

temperature, low-pressure gas refrigerant, and flows out of the heat exchanger 203.

The refrigerant that has flowed out of the heat exchanger 203 is sucked into the

compressor 201 again.

[0029]

In Fig. 1, the case where the refrigerant flows in a fixed direction in the refrigerant

circuit Al is shown as an example, but a path switching device may be provided on the

discharge side of the compressor 201 to make it possible to reverse the flow of the

refrigerant. In the case where the path switching device is provided, the heat

exchanger 100 also functions as an evaporator, and the heat exchanger 203 also

functions as a condenser. As the path switching device, it is possible to use, for

example, a combination of two-way valves, a combination of three-way valves, or a

four-way valve.

[0030]

As the refrigerant to be used in the refrigeration cycle apparatus 200, carbon

dioxide is desirable, but the refrigerant is not necessarily limited to carbon dioxide.

Other than carbon dioxide, it is possible to use natural refrigerant such as hydrocarbons

or helium, alternative refrigerant containing no chlorine, such as HFC410A, HFC407C or

HFC404A, or fluorocarbon refrigerant used in existing products, such as R22 or R134a.

[0031]

[Detailed Configuration of Heat Exchanger 100]

Fig. 3 is an explanatory diagram for explaining an example of providing

protrusions on the first tube. Fig. 4 is an explanatory diagram for explaining a

conventional example of providing protrusions on the first tube as a comparative

example. The first tube will be described in detail based on Fig. 3 in comparison to the

first tube of Fig. 4. In the conventional example of Fig. 4, "X" is added to the end of

reference signs for distinguishing from the first tube 1. A case where two streaks of

protrusions are formed on the first tube using two jigs is described for convenience. In

Figs. 3 and 4, Fig. 3(a) and Fig. 4(a) each schematically illustrate a state of the first tube

seen from a side, and Fig. 3(b) and Fig. 4(b) each schematically illustrate a projection in

which the first tube is projected in the tube axis direction. Further, in Figs. 3 and 4, the

tube axis is shown as a tube axis CL.

[0032] As shown in Fig. 3, when forming two streaks of protrusions 3 on the first tube 1,

a plurality of gearwheel-like jigs are used. One of the gearwheel-like jigs is called a jig

6a, and another is called a jig 6b. The protrusions 3 to be formed by the jig 6a are

called protrusions 3a, and the protrusions 3 to be formed by the jig 6b are called

protrusions 3b. In the state shown in Fig. 3, it is assumed that the protrusions 3a

formed by the jig 6a are placed on the upstream side of the flow of the first heat

medium, and the protrusions 3b formed by the jig 6b are provided on the downstream

side of the flow of the first heat medium.

[0033] The jig 6a has a gearwheel 9A. In the gearwheel 9A, a plurality of protruding

parts 9a for forming the protrusions 3a are provided at mutually different spacing

intervals. When an outside of the first tube 1 is pressed by the jig 6a, an inside of the

first tube 1 protrudes due to the protruding parts 9a of the gearwheel 9A, and a plurality

of protrusions 3a are formed as a streak in a spiral direction. The spacing intervals

between the plurality of protrusions 3a formed by the jig 6a are shown as a pitch 5a, a

pitch 5b, and a pitch 5c.

[0034]

Similarly, the jig 6b has a gearwheel 9B. In the gearwheel 9B, a plurality of protruding parts 9b for forming the protrusions 3b are provided at mutually different

spacing intervals. When the outside of the first tube 1 is pressed by the jig 6b, the

inside of the first tube 1 protrudes due to the protruding parts 9b of the gearwheel 9B,

and a plurality of protrusions 3b are formed as another streak in a spiral direction. The

spacing intervals between the plurality of protrusions 3b formed by the jig 6b are shown

as a pitch 5d, a pitch 5e, and a pitch 5f.

[0035] As shown in Fig. 3, the pitch 5a, the pitch 5b and the pitch 5c of the protrusions

3a are of different lengths. That is, the plurality of protrusions 3a are provided at

unequal spacing intervals.

Similarly, the pitch 5d, the pitch 5e and the pitch 5f of the protrusions 3b are of

different lengths. That is, the plurality of protrusions 3b are provided at unequal

spacing intervals.

Here, the unequal spacing intervals mean that two or more lengths are present as

the spacing intervals between the protrusions 3 formed by each of the jig 6a and the jig

6b.

[0036] The positional relationship between the protrusion 3a and the protrusion 3b is

determined by the phase difference between the gearwheel 9A of the jig 6a and the

gearwheel 9B of the jig 6b. That is, in the jig 6a, the plurality of protruding parts 9a are

provided at unequal spacing intervals, and therefore the plurality of protrusions 3a to be

formed also have unequal spacing intervals. Similarly, in the jig 6b, the plurality of

protruding parts 9b are provided at unequal spacing intervals, and therefore the plurality

of protrusions 3b to be formed also have unequal spacing intervals. Hence, the flow of

the first heat medium is agitated by both the protrusions 3a and the protrusions 3b,

thereby improving the heat exchange performance.

[0037] On the other hand, in the conventional example of Fig. 4, when forming two streaks of protrusions 3X on a first tube 1X, a jig 6aX and a jig 6bX are used, but the spacing interval between protruding parts 9aX of a gearwheel 9AX of the jig 6aX and the spacing interval between protruding parts 9bX of a gearwheel 9BX of the jig 6bX are constant. Moreover, as shown in Fig. 4, the spacing intervals between protrusions 3aX and protrusions 3bX adjacent to each other in a tube axis direction are equal. Thus, as shown in Fig. 4, a pitch 5aX, a pitch 5bX and a pitch 5cX of the protrusions 3aX are of the same length. That is, the plurality of protrusions 3aX are provided at equal spacing intervals. Similarly, a pitch 5dX, a pitch 5eX and a pitch 5fX of the protrusions 3bX are of the same length. That is, the plurality of protrusions 3bX are provided at equal spacing intervals.

[0038] That is, in the jig 6aX, the plurality of protruding parts 9aX are provided at equal

spacing intervals, and therefore the plurality of protrusions 3aX to be formed also have

equal spacing intervals. Similarly, in the jig 6bX, the plurality of protruding parts 9bX

are provided at equal spacing intervals, and therefore the plurality of protrusions 3bX to

be formed also have equal spacing intervals. Hence, the protrusions 3aX and the

protrusions 3bX are all arranged in alignment in the tube axis direction. In this case, the effect of improving the heat exchange performance by the protrusions 3bX provided

on the downstream side is decreased. This is because, at the protrusions 3aX, the

flow of the first heat medium is agitated and the heat exchange performance is

improved, but, at the protrusions 3bX, the flow rate is reduced and the effect of agitating

the flow of the first heat medium is decreased.

[0039]

[Method of Manufacturing First Tube 1]

A method of manufacturing the first tube 1 will be described based on Fig. 3 in

comparison to the conventional example of Fig. 4. Here, a case where two streaks of

protrusions are formed on the first tube using two jigs is also described for convenience.

[0040]

As a method of forming the plurality of protrusions 3 on the inside of the first tube

1, as shown in Fig. 3, the jig 6a having the gearwheel 9A and the jig 6B having the gearwheel 9B are used. In the gearwheel 9A, the plurality of protruding parts 9a are provided. In the gearwheel 9B, the plurality of protruding parts 9b are provided. The protruding parts 9a are pressed against an outer wall of the first tube 1 to form one streak of protrusions 3a in a spiral manner on the inside of the first tube 1. Similarly, the protruding parts 9b are pressed against the outer wall of the first tube 1 to form one streak of protrusions 3b in a spiral manner on the inside of the first tube 1. That is, two streaks of the plurality of protrusions 3 are provided in a spiral manner on the first tube

1.

[0041]

The jig 6a and the jig 6b are rotated independently of each other, and the

protruding parts 9a and the protruding parts 9b provided intermittently are successively

pressed against the outside of the first tube 1. Consequently, the two streaks of

protrusions 3 are formed in a spiral manner on the first tube 1. Since the spacing

intervals between each of the protruding parts 9a and the spacing intervals between

each of the protruding parts 9b are unequal spacing intervals, the protrusions 3a to be

formed by the protruding parts 9a and the protrusions 3b to be formed by the protruding

parts 9b also have unequal spacing intervals.

[0042]

Whereas, in the conventional example shown in Fig. 4, although the two streaks

of protrusions 3X are formed in a spiral manner on the first tube 1X by rotating each of

the jig 6aX and the jig 6bX, the spacing intervals between each of the protruding parts

9aX and the spacing intervals between each of the protruding parts 9bX are regular

spacing intervals, that is, equal spacing intervals. Therefore, the protrusions 3aX to be

formed by the protruding parts 9aX and the protrusions 3bX to be formed by the

protruding parts 9bX also have regular spacing intervals, that is, equal spacing intervals.

[0043]

Fig. 5 is an explanatory diagram for explaining the first tube 1 having the

protrusions 3 formed by the method of Fig. 3. Fig. 6 is an explanatory diagram for

explaining the first tube 1X having the protrusions 3X formed by the method of Fig. 4.

The first tube will be described in detail based on Fig. 5 in comparison to the first tube of

Fig. 6. In Figs. 5 and 6, Fig. 5(a) and Fig. 6(a) each schematically illustrate a state of the first tube seen from a side, and Fig. 5(b) and Fig. 6(b) each schematically illustrate a projection in which the first tube is projected in the tube axis direction. In Figs. 5 and 6, the tube axis is shown as the tube axis CL.

[0044]

As shown in Fig. 5, the protrusions 3a are provided at unequal spacing intervals

on the first tube 1. That is, the pitch 5a, the pitch 5b and the pitch 5c of the protrusions

3a are of different lengths.

Similarly, the protrusions 3b are provided at unequal spacing intervals on the first

tube 1. That is, the pitch 5d, the pitch 5e and the pitch 5f of the protrusions 3a are of

different lengths.

Therefore, even when the spacing intervals between the protrusion 3a and the

protrusion 3b are equal, the protrusion 3a and the protrusion 3b adjacent to each other

in the tube axis direction are not aligned with each other in the tube axis direction.

[0045]

As shown in Fig. 5, the topmost protrusion 3a-1 on the topmost level in the

drawing paper is provided on a straight line Lal, the protrusion 3a-2 on the second level

from the top in the drawing paper is provided on a straight line La2, the protrusion 3a-3

on the third level from the top in the drawing paper is provided on a straight line La3,

and the protrusion 3a-4 on the lowermost level in the drawing paper is provided on a

straight line La4.

Each of the straight lines Lal to La4 is a straight line parallel to the tube axis CL.

In the following description, the straight lines Lal to La4 may be collectively referred to

as straight lines La. The fact that the protrusion 3a is provided on the straight line La

parallel to the tube axis CL means that a portion including the top of the protrusion 3a

overlaps the straight line La.

[0046]

Similarly, the protrusion 3b-1 on the topmost level in the drawing paper is

provided on a straight line Lbl, the protrusion 3b-2 on the second level from the top in

the drawing paper is provided on the straight line La2, a protrusion 3b-3 on the third level from the top in the drawing paper is provided on a straight line Lb3, and the protrusion 3b-4 on the lowermost level in the drawing paper is provided on a straight line Lb4.

Each of the straight lines Lb1-Lb4 is a straight line parallel to the tube axis CL.

In the following description, the straight lines Lbl to Lb4 may be collectively referred to

as straight lines Lb. The fact that the protrusion 3b is provided on the straight line Lb

parallel to the tube axis CL means that a portion including the top of the protrusion 3b

overlaps the straight line Lb.

[0047]

That is, the protrusion 3a-1 and the protrusion 3b-1 are provided on different

straight lines parallel to the tube axis CL, and are not aligned with each other in the tube

axis direction, and similarly the protrusion 3a-2 and the protrusion 3b-2 are provided on

different straight lines parallel to the tube axis CL, and are not aligned with each other in

the tube axis direction. Similarly, the protrusion 3a-3 and the protrusion 3b-3 are

provided on different straight lines parallel to the tube axis CL, and are not aligned with

each other in the tube axis direction. Similarly, the protrusion 3a-4 and the protrusion

3b-4 are provided on different straight lines parallel to the tube axis CL, and are not

aligned with each other in the tube axis direction.

[0048]

Therefore, even at the protrusions 3b provided on the downstream side of the

flow of the first heat medium, the flow rate is not decreased, and the effect of agitating

the flow of the first heat medium is not decreased. Hence, the flow of the first heat

medium is agitated with both the protrusions 3a and the protrusions 3b, and the effect of

improving the heat exchange performance is not decreased.

[0049]

On the other hand, in the conventional example of Fig. 6, the protrusions 3aX are

provided at regular spacing intervals on the first tube 1X. That is, the pitch 5aX, the

pitch 5bX and the pitch 5cX of the protrusions 3aX are of the same length.

Similarly, the protrusions 3bX are provided at regular spacing intervals on the first

tube 1X. That is, the pitch 5dX, the pitch 5eX and the pitch 5fX of the protrusions 3aX are of the same length.

Therefore, when the spacing intervals between the protrusions 3aX and the protrusions 3bX are equal, the protrusion 3aX and the protrusion 3bX adjacent to each

other in the tube axis direction are aligned with each other in the tube axis direction at

some phase difference.

[0050] As shown in Fig. 6, the protrusion 3a-5X on the lowermost level in the drawing

paper is provided on a straight line La5.

Like the straight lines Lal to La4, the straight line La5 is a straight line parallel to

the tube axis CL. The fact that the protrusion 3aX is provided on the straight line La

parallel to the tube axis CL means that a portion including the top of the protrusion 3aX

overlaps the straight line La. The protrusion 3a-4X is provided on the fourth level from

the top in the drawing paper in Fig. 6.

[0051] Similarly, the protrusion 3b-5X on the lowermost level in the drawing paper is

provided on the straight line Lb4.

Like the straight lines Lbl to Lb4, the straight line Lb5 is a straight line parallel to

the tube axis CL. The fact that the protrusion 3bX is provided on the straight line Lb

parallel to the tube axis CL means that a portion including the top of the protrusion 3bX

overlaps the straight line Lb. The protrusion 3b-4X is provided on the fourth level from

the top in the drawing paper in Fig. 6.

[0052] Here, as shown in Fig. 6, in the state seen from a side, the straight line Lal and

the straight line Lbl overlap in the tube axis direction, and are the same straight line.

Similarly, the straight line La2 and the straight line Lb2 overlap in the tube axis direction,

and are the same straight line. Similarly, the straight line La3 and the straight line Lb3

overlap in the tube axis direction, and are the same straight line. Similarly, the straight

line La4 and the straight line Lb4 overlap in the tube axis direction, and are the same

straight line. Similarly, the straight line La5 and the straight line Lb5 overlap in the tube

axis direction, and are the same straight line.

[0053] That is, the protrusion 3a-1X and the protrusion 3b-1X are provided on the same

straight line parallel to the tube axis CL, and are aligned with each other in the tube axis

direction. Similarly, the protrusion 3a-2X and the protrusion 3b-2X are provided on the

same straight line parallel to the tube axis CL, and are aligned with each other in the

tube axis direction. Similarly, the protrusion 3a-3X and the protrusion 3b-3X are

provided on the same straight line parallel to the tube axis CL, and are aligned with

each other in the tube axis direction. Similarly, the protrusion 3a-4X and the protrusion

3b-4X are provided on the same straight line parallel to the tube axis CL, and are

aligned with each other in the tube axis direction. Similarly, the protrusion 3a-5X and

the protrusion 3b-5X are provided on the same straight line parallel to the tube axis CL,

and are aligned with each other in the tube axis direction.

[0054] Therefore, as shown by an arrow F in Fig. 6, at the protrusions 3aX provided on

the upstream side of the flow of the first heat medium, the flow of the first heat medium

is agitated, but, at the protrusions 3bX provided on the downstream side of the flow of

the first heat medium, the flow rate is reduced, and the effect of agitating the flow of the

first heat medium is decreased. That is, the effect of improving the heat exchange

performance with the protrusions 3bX provided on the downstream side of the first heat

medium is decreased.

[0055]

[Modified Example of First Tube 1]

Fig. 7 is an explanatory diagram for explaining other example of forming the

protrusions of the first tube. Based on Fig. 7, the effect achieved by the heat

exchanger 100 including the first tube 1 will be described. In Fig. 7, Fig. 7(a)

schematically illustrates a state of the first tube seen from a side, and Fig. 7(b)

schematically illustrates a projection in which the first tube is projected in the tube axis

direction. Here, a case where two streaks of protrusions are formed on the first tube

using two jigs is described for convenience.

[0056]

Like Fig. 3, in the case of forming the plurality of protrusions 3 in a spiral manner, Fig. 7 schematically shows a case where the protrusions 3 were provided at unequal

spacing intervals so that the spacing interval between the protrusions 3a and the

spacing interval between the protrusions 3b to be added by the identical jig 6a and jig

6b, respectively, had two or more different lengths. Although the jig 6a and the jig 6b

had the same configuration, the spacing interval between the protruding parts 9a and

the spacing interval between the protruding parts 9b have different lengths.

[0057] As shown in Fig. 7, when the spacing interval between the protruding parts 9a

and the spacing interval between the protruding parts 9b are unequal spacing intervals,

the protrusions 3a and the protrusions 3b are also provided at unequal spacing intervals

on the first tube 1. Further, although the spacing interval between the protruding parts

9a and the spacing interval between the protruding parts 9b are made different, some

protrusion 3a and protrusion 3b adjacent to each other in the tube axis direction may be

aligned with each other in the tube axis direction. This case is reviewed. In Fig. 7, the case where the protrusion 3a-1 on the topmost level in the drawing paper and the

protrusion 3b-1 on the topmost position in the drawing paper are aligned with each other

in the tube axis direction is shown as an example.

[0058] Also in Fig. 7, the spacing interval between the protruding parts 9a and the

spacing interval between the protruding parts 9b are unequal spacing intervals, and the

spacing interval between the protruding parts 9a and the spacing interval between the

protruding parts 9b are different between that in the jig 6a and that in the jig 6b, and

therefore the protrusions 3 other than the topmost protrusion 3a-1 and the topmost

protrusion 3b-1 are not aligned with each other in the tube axis direction. Hence, even

when some of the protrusions 3 are aligned with each other in the tube axis direction,

deterioration of the heat exchange performance can be reduced and the heat exchange

performance can be improved compared to the first tube of the conventional example.

[0059]

[Detailed Configuration of Jig 6a and Jig 6b]

Fig. 8 and Fig. 9 are explanatory diagrams for explaining the spacing interval

between the protrusions 3 of the first tube 1. Based on Fig. 8 and Fig. 9, a description will be given for the maximum angle and the minimum angle of the spacing intervals

between the protrusions 3a and the spacing intervals between the protrusions 3b

formed by the jigs of the same configuration, namely the jig 6a and the jig 6b, to realize

unequal spacing intervals between the protrusions 3. In Figs. 8 and 9, Fig. 8(a) and Fig. 9(a) each schematically illustrate a state of the first tube seen from a side, and Fig.

8(b) and Fig. 9(b) each schematically illustrate a projection in which the first tube is

projected in the tube axis direction. An angle e between the protrusions 3a is defined

by two straight lines connecting the center of the first tube 1 and the center of each of

target protrusions 3a.

[0060] First, the minimum value of the angle of the spacing interval between the

protrusions 3a to be added to the first tube 1 by the jig 6a, that is, the minimum angle 61

[rad] will be described based on Fig. 8.

In Fig. 8, a case where five protrusions 3a are provided from the topmost level in

the drawing paper to the lowermost level in the drawing paper is shown as an example,

and the protrusions 3a are shown as the protrusion 3a-1, the protrusion 3a-2, the

protrusion 3a-3, the protrusion 3a-4, and the protrusion 3a-5 from the topmost level in

the drawing paper. It is assumed that the protrusion 3a-1, the protrusion 3a-2, the

protrusion 3a-3, the protrusion 3a-4, and the protrusion 3a-5 are provided in the same

shape and the same size.

[0061] Here, as shown in Fig. 8(b), the width of each of the protrusions 3a, that is, the

diameter of the protrusion 3a is defined as a width W. Moreover, as shown in Fig. 8(b), the length equivalent to the width W of the protrusion 3a is defined as a length 3b1.

Further, the inner diameter of the first tube 1 is defined as an inner diameter Dwi.

[0062] Consider a case where, between the protrusion 3a-1 to be added by the jig 6a

and the protrusion 3a-2 to be added subsequently by the jig 6a, the protrusion 3b is added by the jig 6b. In Fig. 8(b), when the protrusions 3a to be added by the jig 6a and the protrusions 3b to be added by the jig 6b are arranged not to overlap each other, the minimum angle 01 between the protrusion 3a-1 and the protrusion 3a-2 is given by

Expression (1).

[0063]

[Expression 1]

W x 2 4xW Dwi x z Dwi

[0064] Next, the maximum value of the angle of the spacing interval between the

protrusions 3a to be added to the first tube 1 by the jig 6a, that is, the maximum angle

02 [rad] will be described based on Fig. 9. The description will be given on an

assumption that n pieces of protrusions 3 per circumferential length are formed on the

first tube 1.

In Fig. 9, a case where four protrusions 3a are provided from the topmost level in

protrusion 3a-3, and the protrusion 3a-4 from the topmost level in the drawing paper. It

is assumed that the protrusions 3a-1, the protrusion 3a-2, the protrusion 3a-3, and the

protrusion 3a-4 are provided in the same shape and the same size.

[0065] The distance from the protrusion 3a-1 to the protrusion 3a-2 is determined by the

above-mentioned minimum angle 01. The angle from the protrusion 3a-2 to the

protrusion 3a-3 is made 01 x3/2, that is, 1.5 times of 01 so that the protrusions 3a are

provided at unequal spacing intervals without overlapping from the protrusion 3a-1 to

the protrusion 3a-2. Similarly, the angle from the protrusion 3a-3 to the protrusion 3a-4

is made 01 x4/2. Therefore, the angle from the protrusion 3a-1 to the protrusion 3a-4 is

01 x9/2.

[0066]

Thus, an angle corresponding to the maximum angle 92'[rad] of the maximum

spacing interval when the number of the protrusions 3a are four can be given by

Expression (2).

[0067]

[Expression 2]

0 2 '=2 x - -i- - (2) 2

[0068] In Expression (2), when the number of the protrusions 3 to be provided is n (n>2),

the maximum angle 02 can be given by Expression (3).

[0069]

[Expression 3]

2xW xYi 0 2 = 2 x c- i=2 -- . (3) Dwi

[0070]

From the above, the angle between the protrusions 3 to be added by the jig 6a is within the range of Expression (4).

[0071]

[Expression 4]

4x W Dwi 0 5 2 x r - 2 x W Dwi i J -=2(4)

[0072]

Here, the relationship between the adjacent protrusions 3a and 3b is described

by taking, as an example, the case where the protrusions 3 are formed by two jigs,

namely the jig 6a and the jig 6b. That is, the above description applies to the

relationship between the protrusions to be provided adjacent to each other by the respective jigs when the protrusions are formed using the plurality of jigs. However, although the case where the protrusions 3 are formed by the two jigs is described as an example, the number of the jigs is not particularly limited. Even when two or more jigs are used, a range of the angle between each of the protrusions 3 can be given by

Expression (4). Thus, when the spacing intervals of the protrusions 3 to be added by the same jig are made unequal spacing intervals, the effect of improving the heat

exchange performance can be obtained.

[0073]

[Effects Achieved by Heat Exchanger 100, Refrigeration Cycle Apparatus 200 and

Method of Manufacturing Heat Exchanger]

As described above, in the heat exchanger 100, one protrusion 3a and the

protrusion 3b adjacent to the protrusion 3a are provided on different straight lines

parallel to the tube axis direction, and the adjacent protrusions 3 do not overlap each

other in the projection in which the first tube 1 is projected in the tube axis direction.

Therefore, according to the heat exchanger 100, the phenomenon described in Fig. 6 is

less likely to occur, and the heat exchange performance is improved.

[0074]

According to the heat exchanger 100, since the protrusions 3 provided in one

streak are arranged at unequal spacing intervals, it is possible to arrange the adjacent

protrusions 3 not to overlap each other in the projection in which the first tube 1 is

projected in the tube axis direction.

[0075]

According to the heat exchanger 100, since the anglee between the protrusions

3 is arranged to be within the range of Expression (4) described above, it is possible to

arrange the adjacent protrusions 3 not to overlap each other in the projection in which

the first tube 1 is projected in the tube axis direction.

[0076]

According to the refrigeration cycle apparatus 200, since the above-described

heat exchanger is provided as a condenser, an improvement in the heat exchange

performance of the condenser can be expected.

[0077] In the method of manufacturing the heat exchanger 100, the protrusions 3a are

formed at unequal spacing intervals by arranging each of the plurality of protruding parts

9a of the jig 6a at unequal spacing intervals, and the protrusions 3b are formed at

unequal spacing intervals by arranging each of the plurality of protruding parts 9b of the

jig 6b at unequal spacing intervals. Thus, according to the method of manufacturing

the heat exchanger 100, it is possible to manufacture the heat exchanger 100 without

using a special jig and going through a special process.

[0078]

Embodiment 2

Fig. 10 is an explanatory diagram for explaining a shape of a first tube 1A of a

heat exchanger of Embodiment 2 of the present disclosure. Based on Fig. 10, the

shape of the first tube 1A of the heat exchanger of Embodiment 2 will be described.

In Embodiment 2, differences from Embodiment 1 will be mainly described, and

the same parts as those in Embodiment 1 will be labelled with the same reference signs

and description thereof will be omitted. In Fig. 10, Fig. 10(a) schematically illustrates a

state of the first tube seen from a side, and Fig. 10(b) schematically illustrates a

projection in which the first tube is projected in the tube axis direction.

[0079]

In Embodiment 1, the case where the first tube 1 is a circular tube having no

unevenness on the outer circumferential surface is described as an example, whereas,

in Embodiment 2, a case where the first tube 1A is a corrugated tube having a single

streak of spiral groove 35 provided on the outer circumferential surface is described as

an example. When providing the protrusions 3 on the first tube 1A, as shown in Fig.

, the protrusions 3 are provided at portions other than the spiral groove 35. The

second tube is wound around the spiral groove 35 of the first tube 1A.

[0080] Thus, by making the first tube 1A by the corrugated tube, it is possible to further

promote a turbulent flow of the refrigerant inside the first tube 1A. Hence, the heat

exchange performance can be further improved compared to the case where the protrusions are added to the first tube 1 as described in Embodiment 1.

[0081] Embodiment 3

Fig. 11 is an explanatory diagram for explaining a shape of a first tube 1B of a

heat exchanger of Embodiment 3 of the present disclosure. Based on Fig. 11, the

shape of the first tube 1B of the heat exchanger according to Embodiment 3 will be

described.

In Embodiment 3, differences from Embodiment 1 will be mainly described, and

the same parts as those in Embodiment 1 will be labelled with the same reference

signs, and description thereof will be omitted. In Fig. 11, Fig. 11(a) schematically

illustrates a state of the first tube seen from a side, and Fig. 11(b) schematically

illustrates a projection in which the first tube is projected in the tube axis direction.

[0082] In Embodiment 1, the case where the first tube 1 is a circular tube having no

in Embodiment 3, a case where the first tube 1B is a torsion tube having a peak portion

a and a valley portion 30b is described as an example. The peak portion 30a is a

portion that protrudes in a radially expanding direction in which the diameter of the first

tube 1B expands, and is formed in a spiral manner in a direction to which the first heat

medium flows in the first path FP1. The valley portion 30b is a portion in which an

outer diameter of the first tube is smaller than in a portion where the peak portion 30a is

formed, and around which the second tube is to be wound, and is formed in a spiral

manner along the peak portion 30a. When providing the protrusions 3 on the first tube

1B, as shown in Fig. 11, the protrusions 3 are provided in the valley portion 30b. That

is, the protrusions 3 are provided in the spiral direction that is the direction in which the

valley portion 30b is formed. The second tube is wound around the first tube 1B by

being fitted in the valley portion 30b.

[0083] Thus, by making the first tube 1B by the torsion tube, it is possible to further

promote a turbulent flow of the refrigerant inside the first tube 1B. Moreover, the contact area between the first tube 1B and the second tube can be increased. Hence, the heat exchange performance can be further improved compared to the case where the protrusions are added to the first tube 1 as described in Embodiment 1.

[0084] Although the present disclosure is described by separate embodiments, specific

configurations are not limited to the described embodiments, and can be modified within

a range not departing from the gist of the invention.

[0085] It is to be understood that, if any prior art publication is referred to herein, such

reference does not constitute an admission that the publication forms a part of the

common general knowledge in the art, in Australia or any other country.

In the claims which follow and in the preceding description of the invention,

except where the context requires otherwise due to express language or necessary

implication, the word "comprise" or variations such as "comprises" or "comprising" is

used in an inclusive sense, i.e. to specify the presence of the stated features but not to

preclude the presence or addition of further features in various embodiments of the

invention.

Reference Signs List

[0086] 1 first tube, 1A first tube, 1B first tube, 1X first tube, la

inlet, lb outlet, 2 second tube, 2a inlet, 2b outlet, 3 protrusion, 3X protrusion, 3a protrusion, 3a-1 protrusion, 3a-1X protrusion,3a-2 protrusion, 3a-2X protrusion,3a-3 protrusion, 3a-3X protrusion, 3a-4 protrusion, 3a4X protrusion, 3a-5 protrusion, 3a-5X protrusion,3aX protrusion, 3b

protrusion, 3b-1 protrusion, 3b-1X protrusion,3b-2 protrusion, 3b-2X

protrusion, 3b-3 protrusion, 3b-3X protrusion,3b-4 protrusion, 3b-4X

protrusion, 3b-5X protrusion,3b-5X4 protrusion, 3bX protrusion, 5a pitch, 5aX pitch, 5b pitch, 5bX pitch, 5c pitch, 5cX pitch, 5d pitch, 5dX

pitch, 5e pitch, 5eX pitch, 5f pitch, 5fX pitch, 6B jig, 6a jig, 6aX

jig, 6b jig, 6bX jig, 9A gearwheel, 9AX gearwheel, 9B gearwheel,

9BX gearwheel, 9a protruding part, 9aX protruding part, 9b protruding part, 9bX protruding part, 10A heat medium tube, 20A refrigerant

tube, 30a peakportion, 30b valley portion, 35 spiral groove, 60

controller, 100 heat exchanger, 200 refrigeration cycle apparatus, 201

compressor, 202 expansion device, 203 heat exchanger, 203A fan, 205

pump,207 hot water storage tank, Al refrigerant circuit, A2 heat medium

circuit, A3 water supply circuit, FP1 first path, FP2 second path, U hot water supply utility part.

Claims

[Claim 1] A heat exchanger comprising:

a first tube through which a first heat medium flows; and

a second tube through which a second heat medium flows, the second tube being

wound around the first tube,

the first tube having a plurality of protrusions protruding inside of the first tube,

the plurality of protrusions being provided in a plurality of streaks being provided

in a spiral manner in a direction to which the first heat medium of the first path flows in

the first tube,

one streak of the plurality of streaks including the plurality of protrusions each

being arranged at unequal spacing intervals.
[Claim 2]

The heat exchanger of claim 1, wherein, from among the plurality of protrusions

provided in the one streak and the plurality of protrusions provided in an other streak of

the plurality of streaks, two protrusions adjacent to each other in a tube axis direction of

the first tube are each provided on one of different straight lines being in parallel to the

tube axis direction.
[Claim 3]

The heat exchanger of claim 1 or 2, wherein, in a projection in which the first tube

is projected in the tube axis direction,

an angle 0 between the protrusions is arranged to fall within a range given by

expression (5),

[Expression 5]

X 4 xWW 4 x 2 x 7r - 2 x i 2 Dwi Dwi where W is a width of each of the plurality of protrusions,

Dwi is an inner diameter of the first tube, and

n is the number of the plurality of protrusions to be provided per circumferential

length of the first tube.
[Claim 4]

The heat exchanger of any one of claims 1 to 3, wherein the first tube is a

corrugated tube.
[Claim 5]

The heat exchanger of any one of claims 1 to 3, wherein

the first tube includes:

a peak portion protruding in a radially expanding direction in which a diameter of

the first tube expands; and

a valley portion in which an outer diameter of the first tube is smaller than in a

portion where the peak portion is formed, and around which the second tube is wound,

the peak portion being formed in a spiral manner in a direction to which the first

heat medium of the first path flows,

the valley portion being formed in a spiral manner along the peak portion,

the plurality of protrusions being provided in a spiral direction that is the direction

in which the valley portion is formed.
[Claim 6]

A refrigeration cycle apparatus comprising the heat exchanger of any one of

claims 1 to 5 as a condenser, wherein, in the heat exchanger, the first heat medium

flowing through a first path of the first tube constituting the heat exchanger is heated by

the second heat medium flowing through a second path of the second tube constituting

the heat exchanger.
[Claim 7]

A method of manufacturing a heat exchanger including: a first tube in which a first

path through which a first heat medium flows is formed; and a second tube in which a

second path through which a second heat medium flows is formed, the second tube

being wound around the first tube,

the method comprising providing a plurality of protrusions protruding inside of the

first tube in a plurality of streaks in a spiral manner by pressing an outside of the first

tube using a plurality of jigs each having a gearwheel on which a plurality of protruding

parts are provided, wherein, in each of the jigs, the plurality of protruding parts are

arranged at unequal spacing intervals on the gearwheel to provide each of the plurality

of protrusions at unequal spacing intervals.