GB2501413A

GB2501413A - Heat exchanger, method for manufacturing the heat exchanger, and refrigeration cycle device with the heat exchanger

Info

Publication number: GB2501413A
Application number: GB1311658.7A
Authority: GB
Inventors: Hiroaki Nakamune; Susumu Yoshimura; Mizuo Sakai
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2011-01-31
Filing date: 2011-11-14
Publication date: 2013-10-23
Anticipated expiration: 2031-11-14
Also published as: GB2501413B; JP5490265B2; JPWO2012104944A1; GB201311658D0; WO2012104944A1

Abstract

A heat exchanger (100) is provided with: heat transfer members (1) in which refrigerant conduits (3) serving as the conduits for a first refrigerant are formed; and heat transfer tubes (2) serving as the conduits for a second refrigerant. Each of the heat transfer members (1) has fitting grooves (4a, 4b) which are formed in the upper surface and the lower surface of the heat transfer member (1) and in which heat transfer tubes are fitted. The heat exchanger (100) is formed by stacking the heat transfer members (1), and adjacent heat transfer members (1) are connected while the heat transfer tubes (2) are fitted in the fitting grooves (4a, 4b).

Description

DESCRIPTION

Title of Invention

HEAT EXCHANGER, METHOD OF MAKING THE SAME, AND REFRIGERATION

CYCLE APPARATUS INCLUDING THE SAME

Technical Field

[0001] The present invention relates to a heat exchanger that exchanges heat between a first refrigerant and a second refrigerant, a method of making the heat exchanger, and a refrigeration cycle apparatus including the heat exchanger.

Background Art

[0002] Heat exchangers for exchanging heat between a first refrigerant and a second refrigerant have been developed. Such related-art heat exchangers include, for example, a heat exchanger configured such that "the heat exchanger 1 includes an extruded aluminum tube 2 connected between a refrigerant inlet tank 11 and a refrigerant outlet tank 12 and a molded stainless steel tube 3 connected between a tap water inlet header 13 and a tap water outlet header 14, the extruded aluminum tube 2 and the molded stainless steel tube 3 being thermally and hermetically joined by means of joining, such as Nocolok brazing or vacuum brazing" (refer to Patent Literature 1, for example).

Citation List Patent Literature [0003] Patent Literature 1: Japanese Unexamined PatentApplication Publication No. 2001-1 53571 (Paragraph 0026, Fig. 1)

Summary of Invention

Technical Problem [0004] In the related-art heat exchanger, the extruded aluminum tube through which a refrigerant (corresponding to a first refrigerant) flows is joined to the molded stainless steel tube through which tap water (corresponding to a second refrigerant) flows by, for example, brazing. Accordingly, theoccurrenceofa void in a brazing layer joining the tubes reduces the degree of thermal joining of the tubes. Disadvantageously, the performance of heat exchange deteriorates.

[0005] The present invention has been made to solve the above-described disadvantage and provides a heat exchanger which can prevent the performance of heat transfer from deteriorating depending on the degree of thermal joining of joint surfaces and which therefore exhibits good heat exchange performance, a method of making the heat exchanger, and a refrigeration cycle apparatus including the heat exchanger.

Solution to Problem [0006] The present invention provides a heat exchanger including a plurality of heat transfer members each having a plurality of through-holes that serve as passages for a first refrigerant, and a plurality of heat transfer pipes that serve as passages for a second refrigerant. Each of the heat transfer members has a first surface and a second surface opposite the first surface on an outer portion thereof. The first surface and the second surface each have fitting grooves in which the heat transfer pipes are fitted. The plurality of heat transfer members are stacked such that the first surface faces the second surface. The adjacent heat transfer members are connected such that the heat transfer pipes are fitted in the fitting grooves in the first surface and the second surface facing each other [0007] The present invention further provides a method of making the above-described heat exchanger, the method including arranging the heat transfer pipes between the plurality of heat transfer members arranged such that the first surface and the second surface face each other, and pressing the heat transfer members in a direction in which the heat transfer members are stacked to fit the heat transfer pipes into the fitting grooves, thereby connecting the heat transfer members.

[0008] The present invention further provides a refrigeration cycle apparatus including the above-described heat exchanger.

Advantageous Effects of Invention [0009] According to the present invention, the adjacent heat transfer members can cover the heat transfer pipes arranged therebetween such that the heat transfer members are in close contact with outer surfaces (heat transfer surfaces) of the heat transfer pipes. Advantageously, the heat transfer surfaces of the heat transfer pipes can be effectively used. Additionally, the joint surfaces (facing surfaces) of the adjacent heat transfer members do not contribute to heat exchange. Accordingly, the present invention provides a high-performance heat exchanger capable of preventing heat transfer performance from deteriorating depending on the degree of thermal joining of joint surfaces as in related art because brazing or the like is no longer needed, a method of making the heat exchanger, and a refrigeration cycle apparatus including the heat exchanger.

Brief Description of Drawings

[0010] [Fig. 1] Fig. 1 is a perspective view of a unitary heat exchanging unit of a heat exchanger according to Embodiment 1 of the present invention.

[Fig. 2] Fig. 2 is a perspective view of the heat exchanger according to Embodiment 1 of the present invention.

[Fig. 3] Fig. 3 is a perspective view of a unitary heat exchanging unit of a heat exchanger according to Embodiment 2 of the present invention.

[Fig. 4] Fig. 4 is a perspective view of a heat exchanger according to Embodiment 3 of the present invention.

[Fig. 5] Fig. 5 is a perspective view (enlarged view of essential part) of a unitary heat exchanging unit of a heat exchanger according to Embodiment 4 of the present invention.

[Fig. 6] Fig. 6 is a perspective view (enlarged view of essential part) of a unitary heat exchanging unit of a heat exchanger according to Embodiment 5 of the present invention.

[Fig. 7] Fig. 7 is a perspective view of a heat transfer member of a heat exchanger according to Embodiment 6 of the present invention.

[Fig. 8] Fig. 8 is a perspective view of a heat transfer member of a heat exchanger according to Embodiment 7 of the present invention.

[Fig. 9] Fig. 9 is a perspective view of a heat transfer member of a heat exchanger according to Embodiment 8 of the present invention.

[Fig. 10] Fig. 10 is a perspective view of a heat exchanger according to Embodiment 9 of the present invention.

[Fig. 11] Fig. 11 includes diagrams explaining a method of making a heat exchanger according to Embodiment 10 of the present invention.

[Fig. 12] Fig. 12 is a refrigerant circuit diagram illustrating an example ofa refrigeration cycle apparatus according to Embodiment 11 of the present invention.

Description of Embodiments

[0011] Embodiment 1 Fig. 1 is a perspective view of a unitary heat exchanging unit of a heat exchanger according to Embodiment 1 of the present invention.

A heat exchanger 100 according to Embodiment 1 includes a plurality of unitary heat exchanging units A illustrated in Fig. 1 such that the units A are stacked (the heat exchanger 100 will be described in detail later with reference to Fig. 2). Although components of the heat exchanger 100 will be described below on the basis of a direction illustrated in Fig. 1, this direction is not intended to limit the orientation of installation of the heat exchanger 100. Note that some heat transfer pipes 2 are illustrated as being cut in Fig. 1 for illustration of the structure of a heat transfer member 1.

[0012] The unitary heat exchanging unit A includes the heat transfer member 1 in which a first refrigerant flows and the heat transfer pipes 2 in which a second refrigerant flows. The heat transfer member 1 is, for example, substantially rectangular and has therein a plurality of refrigerant passages 3 extending through the heat transfer member 1. The heat transfer member 1 has a plurality of first fitting grooves 4a, in which the heat transfer pipes 2 are fitted, in an upper surface of the heat transfer member 1 such that the first fitting grooves 4a are arranged along, for example, the refrigerant passages 3. The heat transfer member 1 further has a plurality of second fitting grooves 4b, in which the heat transfer pipes 2 are fitted, in a lower surface of the heat transfer member 1 such that the second fitting grooves 4b are arranged along, for example, the refrigerant passages 3. The refrigerant passages 3 correspond to through-holes in the present invention. Additionally, the upper surface of the heat transfer member 1 corresponds to a first surface in the present invention and the lower surface thereof corresponds to a second surface in the present invention. Although the refrigerant passages 3 are laterally arranged in a row, the arrangement of the refrigerant passages is not limited to such a pattern.

For example, a plurality of laterally arranged rows of refrigerant passages 3 may be formed vertically. Alternatively, for example, the refrigerant passages 3 may be staggered. Furthermore, the cross-sectional shape of each refrigerant passage 3 is not limited to a substantially circular shape but may be any shape.

[0013] The heat transfer pipes 2 are substantially circular in cross-section and are fitted in the first fitting grooves 4a and the second fitting grooves 4b of the heat transfer members 1. The first fitting grooves 4a and the second fitting grooves 4b each have an inner surface shaped to fit an outer surface of the heat transfer pipe 2.

Upon fitting of the heat transfer pipes 2 in the first fitting grooves 4a and the second fitting grooves 4b, the outer surfaces of the heat transfer pipes 2 are in close contact with the inner surfaces of the first fitting grooves 4a and the second fitting grooves 4b.

Fig. 1 illustrates a state in which the heat transfer pipes 2 are fitted in the first fitting grooves 4a of the heat transfer member 1.

[0014] It is assumed in Embodiment 1 that the first refrigerant flowing through the refrigerant passages 3 of the heat transfer members 1 is a refrigerant (e.g., a CFC refrigerant, a hydrocarbon refrigerant, or a natural refrigerant, such as carbon dioxide) used for a refrigeration cycle apparatus, such as a heat pump. In Embodiment 1, therefore, the heat transfer member 1 is made of aluminum or aluminum alloy that is resistant to corrosion by this refrigerant. In the case where the heat transfer member 1 is made of aluminum or aluminum alloy, the heat transfer member 1 can be processed (formed) by extrusion at low cost.

Furthermore, it is assumed in Embodiment 1 that the second refrigerant flowing through the heat transfer pipes 2 is, for example, water In Embodiment 1, therefore, the heat transfer pipes 2 are made of copper or copper alloy that is resistant to corrosion by this refrigerant.

[0015] As described above, in the heat exchanger 100 according to Embodiment 1, the materials for the heat transfer member 1 and the heat transfer pipe 2 can be appropriately selected in accordance with the corrosive properties of the first and second refrigerants. The first refrigerant (e.g., a CFO refrigerant, a hydrocarbon refrigerant, or a natural refrigerant, such as carbon dioxide) and the second refrigerant (water) described above are merely examples. Various refrigerants can be selected as the first and second refrigerants depending on a refrigeration cycle apparatus including the heat exchanger 100.

[0016] Fig. 2 is a perspective view illustrating the heat exchanger according to Embodiment 1 of the present invention. Note that some of the heat transfer pipes 2 are illustrated as being cut in Fig. 2 for illustration of the structures of the heat transfer members 1.

As described above, the unitary heat exchanging units A illustrated in Fig. 1 are stacked, thus forming the heat exchanger 100 according to Embodiment 1. More specifically, the heat transfer pipes 2 (the heat transfer pipes 2 fitted in the first fitting grooves 4a) of the unitary heat exchanging unitAdisposed at a lower position are fitted in the second fitting grooves 4b of the unitary heat exchanging unit Adisposed at an upper position, so that the adjacent unitary heat exchanging units A can be connected. The heat exchanger 100 can be formed in this manner.

[0017] The number of unitary heat exchanging units A stacked may be appropriately determined so that the amount of heat exchanged between the first and second refrigerants reaches an intended amount of heat exchanged. Although Fig. 2 illustrates a case where the heat exchanger 100 is configured such that the heat transfer pipes 2 are arranged in the first fitting grooves 4a of the uppermost unitary heat exchanging unit A, the heat transfer pipes 2 do not have to be arranged in the first fitting grooves 4a of the uppermost unitary heat exchanging unitA. In addition, although Fig. 2 illustrates the case where the heat exchanger 100 is configured such that the heat transfer pipes 2 are not arranged in the second fitting grooves 4b of the lowest unitary heat exchanging unit A, it is a matter of course that the heat transfer pipes 2 may be arranged in the second fitting grooves 4b of the lowest unitary heat exchanging unit A. Furthermore, although the unitary heat exchanging units A in which the heat transfer pipes 2 are fitted in the first fitting grooves 4a are stacked to form the heat exchanger 100 in Embodiment 1, the unitary heat exchanging units A in which the heat transfer pipes 2 are fitted in the second fitting grooves 4b may be stacked to form the heat exchanger 100.

[0018] The heat exchanger 100 with the above-described structure can be formed in such a manner that the heat transfer pipes 2 arranged in one unitary heat exchanging unit A are fitted in fitting grooves (the first fitting grooves 4a or the second fitting grooves 4b) of another unitary heat exchanging unitA. Accordingly, the adjacent heat transfer members 1 can cover the heat transfer pipes 2 arranged therebetween such that the heat transfer members 1 are in close contact with the outer surfaces (heat transfer surfaces) of the heat transfer pipes 2. Advantageously, the heat transfer surfaces of the heat transfer pipes can be effectively used. Additionally, the adjacent heat transfer members 1 are symmetrically arranged with respect to joint surfaces 110 (i.e., facing surfaces of the adjacent heat transfer members 1, refer to Fig. 2). Specifically, since the heat transfer members 1 arranged on upper and lower sides of the joint surfaces 110 are at substantially the same temperature, the joint surfaces 110 do not contribute to heat exchange. Thus, deterioration of the performance of heat exchange on the joint surfaces 110 can be prevented. In addition, joining means, such as brazing, is not needed and the likelihood of accurate contact of the joint surfaces 110 can be ensured. The heat exchanger 100 according to Embodiment 1 can therefore achieve higher heat exchange performance than related art.

[0019] Since the heat exchanger 100 according to Embodiment 1 can be formed in such a manner that the heat transfer pipes 2 arranged in one unitary heat exchanging unit A can be fitted in the fitting grooves (the first fitting grooves 4a or the second fitting grooves 4b) of another unitary heat exchanging unit A, the heat exchanger 100 can be easily assembled, thus reducing the cost of processing of the heat exchanger 100.

[0020] Embodiment 2 Although the first fitting grooves 4a and the second fitting grooves 4b of the heat transfer member 1 are arranged along the refrigerant passages 3 in the unitary heat exchanging unit A according to Embodiment 1, the structure of the unitary heat exchanging unit A is not limited to that illustrated in Embodiment 1. For example, the unitary heat exchanging unitA may have the following structure. Note that components which will not particularly be described in Embodiment 2 are the same as those in Embodiment 1 and the same functions and components as those in Embodiment 1 are designated by the same reference numerals and symbols in the

following description.

[0021] Fig. 3 is a perspective view of a unitary heat exchanging unit of a heat exchanger according to Embodiment 2 of the present invention.

A unitary heat exchanging unit A (i.e., a heat exchanger 100) according to Embodiment 2 is configured such that first fitting grooves 4a arranged in an upper surface of a heat transfer member 1 extend substantially orthogonal to refrigerant passages 3. Furthermore, second fitting grooves 4b arranged in a lower surface of the heat transfer member 1 extend along the first fitting grooves 4a. Specifically, the second fitting grooves 4b in the lower surface of the heat transfer member 1 also extend substantially orthogonal to the refrigerant passages 3. The unitary heat exchanging unitAO.e., the heat exchanger 100) according to Embodiment 2, therefore, has a structure in which the heat transfer pipes 2 are arranged substantially orthogonal to the refrigerant passages 3.

[0022] The above-described structure of the unitary heat exchanging unit A allows the first and second refrigerants to flow in a cross flow pattern. In the cross flow, the heat transfer pipes 2 can be arranged in the positions of the refrigerant passages 3 according to a state of the first refrigerant. For example, to heat the second refrigerant utilizing condensation of the first refrigerant, the heat transfer pipes 2 having a small diameter are closely arranged in the positions of the refrigerant passages 3 in which the first refrigerant is in a subcooled state, thus improving the heat exchange performance of the heat exchanger 100. This is particularly effective in a case where, for example, carbon dioxide with a temperature gradient during condensation flows through the refrigerant passages 3. The first fitting grooves 4a and the second fitting grooves 4b can be formed by, for example, cutting after processing (formation) of the refrigerant passages 3 in the heat transfer member 1 by extrusion.

[0023] Embodiment 3 Although the joint surfaces 110 of the adjacent heat transfer members 1 (facing surfaces of the adjacent heat transfer members 1) are in contact with each other to form the heat exchanger 100 in Embodiment 1, the structure is not limited to this case. A clearance may be formed between the joint surfaces 110 of the adjacent heat transfer members 1 to form the heat exchanger 100. Note that components which will not particularly be described in Embodiment 3 are the same as those in Embodiment 1 or Embodiment 2 and the same functions and components as those in Embodiment 1 or Embodiment 2 are designated by the same reference numerals in

the following description.

[0024] Fig. 4 is a perspective view of a heat exchanger according to Embodiment 3 of the present invention.

A heat exchanger 100 according to Embodiment 3 includes a plurality of unitary heat exchanging units A, illustrated in Fig. 1, stacked such that a clearance 111 is provided between joint surfaces 110 of adjacent heat transfer members 1. Since the joint surfaces 110 do not contribute to heat exchange, the same advantages as those in Embodiment 1 or Embodiment 2 can be achieved in the heat exchanger 100 with the above-described structure. Additionally, the clearance 111 provided between the joint surfaces 110 in the heat exchanger 100 according to Embodiment 3 enables easy detection of leakage of the refrigerant from the heat transfer member 1 or the heat transfer pipe 2 caused by, for example, corrosion because the refrigerant flows outward through the clearance 111.

[0025] Embodiment 4 The following modification of the inner surface of each of the refrigerant passages 3 arranged in the heat transfer member 1 and the following modification of the heat transfer pipes 2 enable further improvement of the heat exchange performance of the heat exchanger 100. Note that components which will not particularly be described in Embodiment 4 are the same as those in Embodiments 1 to 3 and the same functions and components as those in Embodiments 1 to 3 are designated by the same reference numerals in the following description.

[0026] Fig. 5 is a perspective view (enlarged view of essential part) of a unitary heat exchanging unit of a heat exchanger according to Embodiment 4 of the present invention. Note that some heat transfer pipes 2 are illustrated as being cut in Fig. 5 for illustration of the structure of a heat transfer member 1.

The heat transfer member 1 of a heat exchanger 100 according to Embodiment 4 includes a plurality of refrigerant passages 31 each having a plurality of grooves in an inner surface thereof. Specifically, the refrigerant passages 31 in Embodiment 4 correspond to the refrigerant passages 3, illustrated in Embodiment 1, in each of which grooves are formed in its inner surface (that is, ridges are formed on the inner surface of the refrigerant passage 3). For example, assuming that the heat transfer member 1 is made of aluminum or aluminum alloy, the grooves can be formed in the inner surface of the refrigerant passage 31 at low cost by extrusion. The above-described structure of the refrigerant passage 31 disturbs the flow of the first refrigerant, thus improving first-refrigerant-side heat transfer performance.

[0027] Each heat transfer pipe 21 of the heat exchanger 100 according to Embodiment 4 has a plurality of grooves in an inner surface thereof. In other words, the heat transfer pipe 21 in Embodiment 4 corresponds to the heat transfer pipe 2, illustrated in Embodiment 1, in which grooves are formed in its inner surface (that is, ridges are formed on the inner surface of the heat transfer pipe 2). The above-described structure of the heat transfer pipe 21 disturbs the flow of the second refrigerant, thus improving second-refrigerant-side heat transfer performance. The grooves in the inner surface of the heat transfer pipe 21 may be arranged so as to extend straight along passages, for example, or may be arranged spirally, for

example.

[0028] As described above, in the heat exchanger 100 including the unitary heat exchanging unitAwith the above-described structure, since the grooves are arranged in the inner surface of each of the refrigerant passages 31 and the heat transfer pipes 21, the heat exchange performance of the heat exchanger 100 can be further improved.

[0029] Although the grooves are arranged in the inner surface of each of the refrigerant passages 31 and the heat transfer pipes 21 in Embodiment 4, the grooves may be formed in the inner surfaces of either the refrigerant passages 31 or the heat transfer pipes 21, thus improving the heat exchange performance of the heat exchanger 100.

[0030] Embodiment 5 The following modification of the heat transfer pipes 21 in Embodiment 4 enables further improvement of the heat exchange performance of the heat exchanger 100. Note that components which will not particularly be described in Embodiment 5 are the same as those in Embodiments 1 to 4 and the same functions and components as those in Embodiments ito 4 are designated by the same

reference numerals in the following description.

[0031] Fig. 6 is a perspective view (enlarged view of essential part) of a unitary heat exchanging unit of a heat exchanger according to Embodiment 5 of the present invention. Note that some heat transfer pipes 2 are illustrated as being cut in Fig. 6 for illustration of the structure of a heat transfer member 1.

A heat exchanger 100 according to Embodiment 5 includes heat transfer pipes different in shape from those in the heat exchanger 100 illustrated in Embodiment 4.

More specifically, each heat transfer pipe 22 according to Embodiment 5 has a flattened tubular shape and further has grooves in an inner surface thereof. Each of first filling grooves 42a and second fitting grooves 42b (corresponding to the first fitting grooves 4a and the second fitting grooves 4b in Embodiment 4) arranged in the heat transfer member 1 has an inner surface shape adapted to an outer surface shape of the heat transfer pipe 22. Specifically, the inner surfaces of the first fitting grooves 42a and the second fitting grooves 42b are shaped such that when the heat transfer pipes 22 are fitted into the first fitting grooves 42a and the second fitting grooves 42b, the outer surfaces of the heat transfer pipes 22 are in close contact with the inner surfaces of the first fitting grooves 42a and the second fitting grooves 42b.

[0032] According to Embodiment 5, a unitary heat exchanging unit A is formed as follows, for example. A heat transfer pipe having a substantially circular cross-section (the heat transfer pipe 21 illustrated in Embodiment 4) is disposed in each of the first fitting grooves 42a arranged in the heat transfer member 1. The heat transfer member 1 and the heat transfer pipes having the substantially circular cross-section are subjected to, for example, pressing, so that the heat transfer pipes having the substantially circular cross-section become the flattened heat transfer pipes 22 and are therefore fitted in the first fitting grooves 42a. Naturally, the heat transfer pipes 22 which have been originally flattened may be fitted into the first fitting grooves 42a.

[0033] In the heat exchanger 100 including the unitary heat exchanging unitAwith the above-described structure, the use of the flattened heat transfer pipes 22 enables the characteristic length of the heat transfer pipe 22 to be less than that of the heat transfer pipe 21 illustrated in Embodiment 4, thus achieving higher heat transfer performance than the heat exchanger 100 according to Embodiment 4.

[0034] Although the flattened heat transfer pipes 22 each having the grooves in the inner surface thereof are used in Embodiment 5, flattened heat transfer pipes each having no grooves in the inner surface thereof may be naturally used. The use of such heat transfer pipes can achieve higher heat transfer performance than the heat exchanger 100 according to Embodiment 1.

[0035] Embodiment 6 The heat exchanger according to each of Embodiments 1 to 5 may be provided with the following connecting pipe. In the following description, it is assumed that the connecting pipe is provided for the heat transfer member 1 illustrated in Embodiment 1. Note that components which will not particularly be described in Embodiment 6 are the same as those in Embodiments 1 to 5 and the same functions and components as those in Embodiments 1 to 5 are designated by the same reference

numerals in the following description.

[0036] Fig. 7 is a perspective view of a heat transfer member of a heat exchanger according to Embodiment 6 of the present invention.

A heat transfer member 1 according to Embodiment 6 has a communicating hole 5 in the vicinity of a front end (first end) thereof, the communicating hole 5 having one end that opens into a right side surface of the heat transfer member 1. The communicating hole 5 communicates with each refrigerant passage 3 disposed in the heat transfer member 1. A connecting pipe 6 is attached to an opening of the communicating hole 5 by, for example, brazing. Furthermore, a substantially cylindrical plug 9 is, for example, press-fitted in an end of each refrigerant passage 3 adjacent to the communicating hole 5 (the connecting pipe 6) such that the end of the refrigerant passage 3 is closed. The plug 9 may be fixed to the refrigerant passage 3 by, for example, brazing, such that the end of the refrigerant passage 3 is closed.

[0037] In a heat exchanger 100 including the heat transfer member 1 with the above-described structure, the refrigerant flowing through the plurality of refrigerant passages 3 can be allowed to flow into and out of the single connecting pipe 6, thus simplifying the structure of the heat exchanger 100.

[0038] Although the end of each refrigerant passage 3 is closed by the plug 9 in Embodiment 6, the refrigerant passage 3 can be closed by any of various means.

For example, the end of the refrigerant passage 3 may be closed by a brazing material alone.

Additionally, although Fig. 7 illustrates the structure of the heat transfer member 1 at and in the vicinity of the front end (first end) thereof, the connecting pipe 6 may be naturally disposed in the vicinity of a rear end (second end) of the heat transfer member 1. Specifically, each of the two ends of the refrigerant passage 3 may be connected to one passage. The placement of the connecting pipe 6 in the vicinity of each of the two ends of the heat transfer member 1 can further simplify the structure of the heat exchanger 100.

[0039] Although the heat transfer member 1 has the communicating hole 5 and is provided with the connecting pipe 6 attached to the hole in Embodiment 6, the connecting pipe 6 may be provided in any of various manners. For example, the connecting pipe 6 may be disposed at one end (for example, the front end) of the heat transfer member 1. As long as the connecting pipe 6 has through-hales that open into a side surface thereof (more specifically, at positions corresponding to ends of the refrigerant passages 3), the refrigerant passages 3 can be permitted to communicate with the connecting pipe 6. Consequently, the refrigerant tlowing through the plurality of refrigerant passages 3 can be allowed to flaw into and out of the single connecting pipe 6, thus simplifying the structure of the heat exchanger 100.

[0040] Embodiment 7 In the case where the heat transfer member 1 has the communicating hole 5 and is provided with the connecting pipe 6 attached to the hole, the end of each refrigerant passage 3 may be closed as follows, for example. In the following description, it is assumed that the connecting pipe is provided for the heat transfer member 1 illustrated in Embodiment 1. Note that components which will not particularly be described in Embodiment 7 are the same as those in Embodiments 1 to 6 and the same functions and components as those in Embodiments 1 to 6 are designated by the same reference numerals in the following description.

[0041] Fig. 8 is a perspective view of a heat transfer member of a heat exchanger according to Embodiment 7 of the present invention.

A heat transfer member 1 according to Embodiment 7 has a communicating hole 5 in the vicinity of an end (at least one of a front end and a rear end) thereof, the communicating hole Shaving one end that opens into a right side surface of the heat transfer member 1, as in Embodiment 6. The communicating hole 5 communicates with each refrigerant passage 3 disposed in the heat transfer member 1. A connecting pipe 6 is attached to an opening of the communicating hole 5 by, for

example, brazing.

[0042] The heat transfer member 1 according to Embodiment 7 is provided with a blocking plate 10 having a shape adapted to each of ends (the front end and the rear end) of the heat transfer member 1. The blocking plate 10 is fixed to the end of the heat transfer member 1 by, for example, brazing, thus closing an end of each refrigerant passage 3.

[0043] In a heat exchanger 100 including the heat transfer member 1 with the above-described structure, the refrigerant flowing through the plurality of refrigerant passages 3 can be allowed to flow into and out of the single connecting pipe 6, thus simplifying the structure of the heat exchanger 100.

[0044] Embodiment 8 In the case where the heat transfer member 1 has the communicating hole 5 and is provided with the connecting pipe 6 attached to the hole, the end of each refrigerant passage 3 may be closed as follows, for example. In the following description, it is assumed that the connecting pipe is provided for the heat transfer member 1 illustrated in Embodiment 1. Note that components which will not particularly be described in Embodiment 8 are the same as those in Embodiments 1 to 7 and the same functions and components as those in Embodiments 1 to 7 are designated by the same reference numerals in the following description.

[0045] Fig. 9 is a perspective view of a heat transfer member of a heat exchanger according to Embodiment 8 of the present invention.

A heat transfer member 1 according to Embodiment 8 has a communicating hole 5 in the vicinity of an end (at least one of a front end and a rear end) thereof, the communicating hole Shaving one end that opens into a right side surface of the heat transfer member 1, as in Embodiments 6 and 7. The communicating hole 5 communicates with each refrigerant passage 3 disposed in the heat transfer member 1. A connecting pipe 6 is attached to an opening of the communicating hole 5 by, for example, brazing. Furthermore, the end (at least one of the front end and the rear end), in which the connecting pipe 6 is attached, of the heat transfer member 1 according to Embodiment 8 is pinched, thus closing an end of each refrigerant passage 3.

[0046] In a heat exchanger 100 including the heat transfer member 1 with the above-described structure, the refrigerant flowing through the plurality of refrigerant passages 3 can be allowed to flow into and out of the single connecting pipe 6, thus simplifying the structure of the heat exchanger 100.

Additionally, since the end of the heat transfer member 1 is pinched such that the end of each refrigerant passage 3 can be closed, it is unnecessary to additionally place a member for closing the end of each refrigerant passage 3, thus reducing the processing cost. Naturally, for example, brazing may be performed after pinching.

[0047] Embodiment 9 The heat exchanger 100 may be provided with a header pipe to simplify pipe arrangement around the heat exchanger 100. In the following description, it is assumed that the heat exchanger 100 includes the heat transfer member 1 illustrated in Embodiment 6. Note that components which will not particularly be described in Embodiment 9 are the same as those in Embodiments 1 to 8 and the same functions and components as those in Embodiments 1 to 8 are designated by the same

reference numerals in the following description.

[0048] Fig. 10 is a perspective view of a heat exchanger according to Embodiment 9 of the present invention. Note that some heat transfer pipes 2 are illustrated as being cut in Fig. 10 for illustration of the structures of a heat transfer member 1.

As illustrated in Fig. 10, a heat exchanger 100 according to Embodiment 9 includes a header pipe 7 and a header pipe 8. The header pipe 7 communicates with connecting pipes 6 provided for unitary heat exchanging units A. The header pipe 7 allows the refrigerant flowing through the plurality of connecting pipes 6 to flow into and out of the single header pipe 7, thus simplifying pipe arrangement around the heat exchanger 100. Advantageously, a space for installation of the heat exchanger can be reduced. The header pipe 7 corresponds to a first refrigerant header pipe in the present invention.

[0049] The header pipe 8 communicates with the heat transfer pipes 2 provided for each unitary heat exchanging unit A. The header pipe 8 allows the refrigerant flowing through the plurality of heat transfer pipes 2 to flow into and out of the single header pipe 8, thus simplifying the pipe arrangement around the heat exchanger 100.

Accordingly, the installation space for the heat exchanger 100 can be reduced. The header pipe 8 corresponds to a second refrigerant header pipe in the present invention.

[0050] Although Embodiment 9 has been described with respect to the case where both of the header pipe 7 and the header pipe 8 are arranged, the pipe arrangement around the heat exchanger 100 can be simplified by placement of either one of the header pipes. The installation space for the heat exchanger 100 can therefore be reduced.

[0051] Embodiment 10 In Embodiment 1, the unitary heat exchanging units A are formed and, after that, the unitary heat exchanging units A are stacked to form the heat exchanger 100.

The method of making the heat exchanger is not limited to the above one. The heat exchanger 100 may be formed by using the following method of making, for example.

Note that components which will not particularly be described in Embodiment 10 are the same as those in Embodiments 1 to 9 and the same functions and components as those in Embodiments 1 to 9 are designated by the same reference numerals in the

following description.

[0052] Fig. 11 includes diagrams explaining a method of making a heat exchanger according to Embodiment 10 of the present invention. Note that some heat transfer pipes 2 are illustrated as being cut in Fig. 11 for illustration of the structures of heat transfer members 1.

A heat exchanger 100 according to Embodiment 10 is made by the following procedure.

[0053] The heat transfer member 1 is placed as illustrated in Fig. 11(a).

[0054] Subsequently, as illustrated in Fig. 11(b), the heat transfer pipes 2 are placed on first fitting grooves 4a of the heat transfer member 1 placed in Fig. 11(a).

[0055] Referring to Fig. 11(c), the heat transfer members 1 and the heat transfer pipes 2 illustrated in Fig. 11(b) are then stacked. More specifically, the heat transfer member 1 is placed on the heat transfer pipes 2 such that the heat transfer pipes 2 illustrated in Fig. 11(b) are arranged under second fitting grooves 4b. The heat transfer pipes 2 are arranged on the first fitting grooves 4a of the heat transfer member 1. These steps are repeated to stack a desired number of combinations each including the heat transfer member 1 and the heat transfer pipes 2.

[0056] After that, as illustrated in Fig. 11(d), the heat transfer members 1 and the heat transfer pipes 2 stacked as illustrated in Fig. 11(c) are subjected to pressing, namely, thrust (or pressed) in a direction in which the heat transfer members 1 are stacked.

The pressing causes the heat transfer pipes 2 to be fitted into the first fitting grooves 4a of the heat transfer member 1 placed under the heat transfer pipes 2 and to be fitted into the second fitting grooves 4b of the heat transfer member 1 placed above the heat transfer pipes 2. As described above, the method of making illustrated in Embodiment 10 enables the heat exchanger 100 to be made in a single process, thus reducing the processing cost of the heat exchanger 100.

[0057] Although Embodiment 10 has been described with respect to the case where two combinations each including the heat transfer member 1 and the heat transfer pipes 2 are stacked, three or more combinations each including the heat transfer member 1 and the heat transfer pipes 2 may be naturally stacked. Furthermore, although the heat transfer pipes 2 are arranged in the uppermost first fitting grooves 4a in the heat exchanger 100 according to Embodiment 10, the heat transfer pipes 2 do not have to be arranged in the uppermost first fitting grooves 4a. Accordingly, only the heat transfer members 1 serve as upper and lower surfaces to be pressed, thus providing a symmetrical shape. Advantageously, a pressing jig can be simplified.

[0058] In a case where each heat transfer member 1 is provided with the connecting pipe 6 as illustrated in Embodiments 6 to 8, the heat transfer members 1 with the connecting pipes 6 may be processed as illustrated in Fig. 11(a) to Fig. 11(d). This manner of making the heat exchanger 100 offers an advantage in that the heat exchanger 100 can be easily made, because processing of details, that is, processing of ends of each heat transfer member 1 (i.e., processing of the communicating hole 5 and closing of ends of refrigerant passages 3) can be performed first.

[0059] In a case where the heat exchanger 100 is provided with header pipes 8 as illustrated in Embodiment 9, each header pipe 8 may be connected to the plurality of heat transfer pipes 2 in advance and the process illustrated in Fig. 11(b) to Fig. 11(d) may be performed using these pipes. This manner of making the heat exchanger offers an advantage in that the process can be easily performed, because the number of post-processing steps is reduced.

[0060] Embodiment 11 The heat exchanger 100 according to each of Embodiments ito 10 can be included in, for example, the following refrigeration cycle apparatus. Note that components which will not particularly be described in Embodiment 11 are the same as those in Embodiments 1 to 10 and the same functions and components as those in Embodiments 1 to 10 are designated by the same reference numerals in the following

description.

[0061] Fig. 12 is a refrigerant circuit diagram illustrating an example of a refrigeration cycle apparatus according to Embodiment 11 of the present invention.

A refrigeration cycle apparatus 200 according to Embodiment 11 includes a heat source side refrigerant circuit 210 and a use side refrigerant circuit 220. In the heat source side refrigerant circuit 210, the first refrigerant flows. The heat source side refrigerant circuit 210 includes a compressor 201, a refrigerant passage 3 of a heat exchanger 100, a pressure reducing device 202, such as an expansion valve, and an evaporator 203 which are sequentially connected by pipes. The use side refrigerant circuit 220, in which the second refrigerant (e.g., water) flows, is connected to a heat transfer pipe 2 of the heat exchanger 100 and a use side device (not illustrated). In a case where the refrigeration cycle apparatus 200 is used as a hot water storage apparatus, the use side device is a hot water tank, for example. In a case where the refrigeration cycle apparatus 200 is used as an air-conditioning apparatus, the use side device is an indoor heat exchanger, for example.

[0062] In the use of the heat exchanger 100 in the refrigeration cycle apparatus 200 as illustrated in Fig. 12, the second refrigerant (e.g., water) is heated by the first refrigerant in the heat exchanger 100. The heated second refrigerant (e.g., water) is supplied to the use side device. For example, in the case where the refrigeration cycle apparatus 200 is used as a hot water storage apparatus, the heated water is stored in, for example, a hot water tank. For example, in the case where the refrigeration cycle apparatus 200 is used as an air-conditioning apparatus, the heated water heats indoor air in an indoor heat exchanger, thus heating an indoor space.

[0063] Since the refrigeration cycle apparatus 200 with the above-described configuration includes the heat exchanger 100 according to any of Embodiments 1 to 10, the refrigeration cycle apparatus 200 with a small footprint and high performance can be provided.

[0064] Although the heat exchanger 100 is used as a radiator (condenser) in the heat source side refrigerant circuit 210 in Embodiment 11, the heat exchanger 100 may be used as an evaporator in the heat source side refrigerant circuit. In this case, the second refrigerant cooled by the first retrigerant can be supplied to the use side device.

Reference Signs List [0065] 1, heat transfer member; 2, heat transfer pipe; 3, refrigerant passage; 4a, first fitting groove; 4b, second fitting groove; 5, communicating hole; 6, connecting pipe; 7, header pipe; 8, header pipe; 9, plug; 10, blocking plate; 21, heat transfer pipe (with grooves); 22, heat transfer pipe (flattened pipe); 31, refrigerant passage (with grooves); 42a, first fitting groove; 42b, second fitting groove; 100, heat exchanger; 110, joint surface; 111, clearance; 200, refrigeration cycle apparatus; 201, compressor; 202, pressure reducing device; 203, evaporator; 210, heat source side refrigerant circuit; and 220, use side refrigerant circuit.