JP2003254683A - Heat exchanger and absorption refrigerating machine using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive and strong heat exchanger by forming a constant falling liquid film, and also to provide a compact and high performance absorption refrigerating machine using it. <P>SOLUTION: In this heat exchanger, a plurality of heat exchanger pipes 3 having a shape to be bent at an intermediate part of the pipe for reversing a flow direction are stacked in an upward and downward direction with the bent shapes at the intermediate parts sequentially changed in a manner that an inner face and an outer face of the pipes 3 are almost brought into close contact with each other, so as to form a heat exchanger pipe unit 4. The units 4 are arranged in a horizontal direction at predetermined intervals, so that heats are exchanged between in-pipe fluid flowing inside the pipe 3 and out-pipe fluid flowing outside the pipe 3. Both ends of the pipe 3 are jointed with a pipe plate or a header for in-pipe fluid. As to outside dimension at both ends of the pipe 3, the center part of the pipe 3 is shaped like a circle, and the intermediate part except for the both ends of the pipe 3 is shaped like an ellipse or a general rectangle longer in an upward and downward direction. Height dimension in the upward and downward direction of the intermediate part is larger than the outside diameter of both ends. In this absorption refrigerating machine, the heat exchanger is used for at least one of facilities constituting the absorption refrigerating machine. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heat exchanger,
In particular, it relates to a compact and high-performance falling-film heat exchanger and an absorption refrigerator using the same.

[0002]

2. Description of the Related Art Conventional heat exchangers for absorption refrigerators, particularly evaporators, absorbers, regenerators and condensers, have mainly been shell-and-tube type as falling-film heat exchangers. . This heat exchanger has become considerably compact due to the development of various high-performance heat transfer tubes, but in recent years, a plate heat exchanger has been proposed for further compactness and higher performance. However, the conventional plate heat exchanger has the following problems to be solved. A large number of uneven parts provided around the thin plate and in the internal flow path are joined by brazing or welding, but if there is an incomplete part in this joint, poor airtightness and insufficient strength will occur, resulting in reliability. There is a difficulty in securing. It is difficult to form a thin and uniform falling film over the wide heat transfer surface. High cost compared to commercial heat transfer tubes. In addition, the refrigerant vapor flow velocity is considerably high in the absorption refrigerator, and the pressure loss due to this is a factor causing the performance of the absorption refrigerator to deteriorate.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, forms a uniform falling liquid film, and is an inexpensive and strong heat exchanger, and a compact and high-performance heat exchanger using the same. An object is to provide an absorption refrigerator.

[0004]

In order to solve the above-mentioned problems, in the present invention, heat transfer tubes having a shape bent so as to reverse the flow direction at the heat transfer tube intermediate portion are provided on top of each other. In the heat transfer tube, the heat transfer tube unit is formed by vertically stacking a plurality of heat transfer tubes in which the bent shapes of the intermediate portions are sequentially changed so as to be in close contact with each other on the lower surface, and the heat transfer tube units are horizontally arranged at predetermined intervals. A heat exchanger for exchanging heat between a fluid inside a tube flowing through and a fluid outside the heat transfer tube, wherein both ends of the heat transfer tube are joined to a tube plate or a header for the fluid inside the tube. Both ends have a circular shape, and the middle part other than both ends of the heat transfer tube has an oval shape or a substantially long quadrangle that is long in the vertical direction, and has a structure in which the height dimension in the vertical direction in the middle part is larger than the outer diameter of both ends. It was decided In the heat exchanger, the heat transfer tube is
It is preferable that the outer surface is subjected to hydrophilic treatment for improving wettability, and the heat transfer tube unit is positioned on the upper surface of the uppermost heat transfer tube and the lower surface of the lowermost heat transfer tube that form the unit. It is possible to provide not only a guide member for use in the heat transfer tube but also a binding member that binds the heat transfer tubes constituting the heat transfer tube unit and the guide member.

Further, according to the present invention, an absorption refrigerating machine is used in which at least one of the evaporator, the absorber, the regenerator and the condenser constituting the absorption refrigerating machine uses the heat exchanger. . The absorption refrigerating machine is provided with the heat exchanger as it is for a condenser, or for an evaporator by providing a refrigerant spraying device on the upper part of the heat transfer tube unit, or on the upper part of the heat transfer tube unit with an absorbing solution spraying device. It can be used for any one or more as an absorber or a regenerator,
Further, the heat exchanger, a refrigerant spraying device, an absorbing solution spraying device are alternately provided on the upper part of the heat transfer tube unit, and a recovering device for separating and recovering either the refrigerant or the absorbing solution is provided on the lower part, alternately. Used for evaporator and absorber,
The evaporator heat transfer tube end can be joined to one tube plate side, and the absorber heat transfer tube end can be used by joining to the other side tube plate, and the heat exchanger can be used as a heat transfer tube unit. An absorbing solution spraying device is installed every other row on the upper part, and a collector for separating and recovering either the refrigerant or the absorbing solution is installed on the lower part, which is used alternately for the regenerator and the condenser, and at the end of the heat transfer tube for the regenerator. Can be joined to one tube sheet side, and the heat transfer tube end for the condenser can be joined to the other tube sheet side for use.
Further, when the heat exchanger is used for both the absorber and the condenser at the same time, is the heat exchanger joined to one of the two tube plates arranged at both ends of the heat exchanger of the heat exchanger? Alternatively, the absorber tube plate and the condenser tube plate may be configured by a single tube plate. Further, in the heat transfer tube unit of the heat exchanger used in the absorption refrigerating machine, a non-condensable gas extraction pipe can be provided in a space in the vertical middle portion of the unit.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view of a cross-sectional configuration diagram showing an example of the heat exchanger of the present invention. In FIG. 1, six heat transfer tube units 4 are arranged in a container composed of a shell 1 and tube plates 2 at both ends. FIG. 2 is a cross-sectional configuration diagram showing another example of the heat exchanger of the present invention, (a) is a front view, (b) is a cross-sectional view of the binding member 23 of (a), and (c) is a pipe end portion. Side view,
(D) is a cross-sectional view taken along line XX of (a), and (e) is Y of (a).
FIG. FIG. 2A shows a state in which a heat transfer tube unit 4 in which five heat transfer tubes 3 bent in a U shape are stacked is joined to a tube plate on one side. Here, the shape of the bent portion is concentric, but it may be bent in a rectangular shape. The tube plate 2 and the heat transfer tube 3 may be fixed by any of tube expansion, welding and brazing.

A liquid spraying device 5 is provided above the heat transfer tube unit 4 so that the liquid flows down to the outside of the heat transfer tube. A header 10 for supplying a fluid flowing in the heat transfer tube is provided on the right tube plate 2. Guide members 20 are provided on the upper and lower portions of the heat transfer tube unit 4. The guide member 20 is fixed to the tube sheets 2 at both ends and is used to accurately determine the position of the heat transfer tube unit 4. The guide member 20 is preferably a pipe-shaped member having the same outer diameter dimension as the heat transfer tube 3. A non-condensable gas extraction pipe 21 is provided in a space in the middle of the heat transfer tube unit 4, and extraction holes 22 are provided below the pipe 21 at appropriate intervals.

FIG. 2B is a sectional view of the binding member 23 for fixing the heat transfer tube 3. The bundling member 23 is used for vertically aligning the heat transfer tubes 3. At the upper and lower ends and the middle part, the two members fixed by bolts are heat transfer tubes 3
The guide member 20 is fixed so as to be sandwiched. In FIG. 2C, pitches P1 and P2 are provided as spaces for fixing to the tube plate 2 at the end of the heat transfer tube. The pitches P1 and P2 can be arbitrarily determined according to the outer diameter of the heat transfer tube 3. In FIG. 2C, the heat transfer tube 3 is
Three heat transfer tube units 4 composed of five and four are arranged. Further, the heat transfer tubes are arranged in a staggered pattern, but of course they may be arranged in a grid pattern.

In the XX sectional view of FIG. 2 (a),
The five heat transfer tubes 3 are vertically and closely stacked to form a heat transfer tube unit 4. A state in which the refrigerant or the absorbing solution sprayed from the spraying device is flowing down outside the heat transfer tube 3 is illustrated. According to the present invention, the contact surface of the elliptical heat transfer tube has a shallower recess on the contact surface as compared with the circular heat transfer tube, so that the thermal resistance is reduced and a thin liquid pool in the lateral direction is formed. It is possible to form a uniform thin film on the outer surface of the heat pipe, but in order to further improve the wet spreadability,
It is preferable to apply a hydrophilic treatment to the outer surface of the heat transfer tube. The hydrophilic treatment can be achieved by forming irregularities on the surface of the heat transfer tube by means of an oxide film, shot blasting, metal spraying, or the like. The close contact gap of the heat transfer tube 3 is not specified, but 0
It is preferably about 2 mm. The end shape of the heat transfer tube 3 is shown in FIG.
As shown in (e), the heat transfer tubes are in close contact with each other at the center of the heat transfer tube, but are separated at the end of the heat transfer tube. The outer diameter D of the central portion of the heat transfer tube and the outer diameter d of the end portion of the heat transfer tube can be arbitrarily determined according to the required joining space.

FIG. 3 is a cross-sectional structural view showing an example in which the heat exchanger of the present invention is used in an absorption refrigerator. In the container surrounded by the shell 1, the evaporator heat transfer tube unit 4E and the absorber heat transfer tube are shown. The unit 4A is arranged on the left and right. In the evaporator heat transfer tube unit 4E, the cold water flows inside the heat transfer tube, and the refrigerant liquid flows down from the liquid spraying device 5E to the outside of the heat transfer tube. During cooling, the refrigerant water exchanges heat with the cold water and a part of the refrigerant liquid evaporates. . In the absorber heat transfer tube unit 4A, cooling water flows in the heat transfer tube,
The absorbing solution flows down from the liquid spraying device 5A to the outside of the heat transfer tube, and absorbs the refrigerant vapor from the evaporator while flowing down. An eliminator 6 is arranged between the evaporator and the absorber to prevent droplets from scattering. In order to prevent heat loss between the refrigerant reservoir under the evaporator and the absorbent solution reservoir under the absorber,
A heat insulating space in an inverted U shape is provided. It is also possible to replace the evaporator part with a regenerator and further replace the absorber part with a condenser. In this case, the condenser unit has a liquid spraying device 5A.
Is unnecessary. In the heat exchanger tube unit for a regenerator, a heating fluid (steam, hot water, etc.) flows in the heat exchanger tube, an absorbing solution flows down outside the heat exchanger tube, and a refrigerant vapor is generated from the absorbing solution in the middle of the flowing down. In the heat transfer tube unit for the condenser, the cooling water flows inside the heat transfer tube, the refrigerant vapor from the regenerator is condensed outside the heat transfer tube, and the condensed refrigerant liquid flows down.

FIG. 4 is a sectional view showing another example in which the heat exchanger of the present invention is used in an absorption refrigerator. In FIG. 4, three evaporator heat transfer tube units 4E are joined to the tube plate 2 on the right side, and a cold water header 10 is provided. To the tube plate 2 on the left side, three absorber heat transfer tube units 4A are joined and a cooling water header 11 is provided. With such an arrangement, the cold water header and the cooling water header can be easily constructed. Inside the shell 1, evaporator heat transfer tube units 4E and absorber heat transfer tube units 4A are alternately arranged.

FIG. 5 is a sectional view of the side surface of the absorption refrigerator shown in FIG. 4 as viewed from the right. In FIG. 5, three evaporator heat transfer tube units 4E and three absorber heat transfer tube units 4A are alternately arranged in a container surrounded by the shell 1. With this arrangement, since the refrigerant vapor evaporated in the evaporator flows toward the adjacent absorber heat transfer tube unit, the vapor flow velocity is extremely low, so the pressure loss is small and the performance of the absorption refrigerator can be improved. it can. In the evaporator heat transfer tube unit 4E, the cold water flows inside the heat transfer tube, the refrigerant liquid flows down to the outside of the heat transfer tube, and heat exchanges with the cold water during the flow to evaporate part of the refrigerant liquid. In the absorber heat transfer tube unit 4A, cooling water flows inside the heat transfer tube, and the absorbing solution flows down outside the heat transfer tube,
The refrigerant vapor from the evaporator is absorbed during the flow.

At the top of the evaporator heat transfer tube unit 4E,
Refrigerant spraying device 5E is also used for absorber heat transfer tube unit 4A.
The absorbent solution spraying device 5A is disposed on the upper part of.
The spraying devices 5E and 5A may be integrally formed with each heat transfer tube unit or may be installed independently. Also in this spraying device, it is preferable that the surface in contact with the liquid is subjected to hydrophilic treatment. This hydrophilic treatment makes it possible to obtain a good spraying state. Further, a collector 7 for separating and collecting the refrigerant and the absorbing solution is provided in the lower part of the evaporator heat transfer tube unit 4E or the absorber heat transfer tube unit 4A. FIG. 5 shows an example provided in the lower portion of the evaporator heat transfer tube unit. The refrigerant liquid recovered by the recovery device 7 is guided to the refrigerant liquid reservoir (not shown) and can be prevented from being mixed with the absorbing solution.

It is also possible to replace the evaporator part with a regenerator and further replace the absorber part with a condenser. In this case, the liquid spraying device 5A is unnecessary in the condenser section. In the heat transfer tube unit for the regenerator, the heating fluid (steam,
Hot water, etc.) flows, and the absorbing solution flows down outside the heat transfer tube, and refrigerant vapor is generated from the absorbing solution on the way down. In the heat transfer tube unit for the condenser, the cooling water flows inside the heat transfer tube, the refrigerant vapor from the regenerator is condensed outside the heat transfer tube, and the condensed refrigerant liquid flows down. FIG. 6 is a sectional configuration view of the absorption refrigerator shown in FIG. 4 viewed from the front side. In FIG. 6, the heat transfer tube unit for the evaporator is joined to the right tube plate, and the heat transfer tube unit for the absorber is joined to the left tube plate. In FIG. 6, cold water flows into the header 10 from the inlet 8, passes through the evaporator heat transfer tube unit 4E, and flows out from the header 10 provided on the upper part of the same tube sheet. In addition, the cooling water is at the inlet 9
Flows into the header 11 from the heat transfer tube unit 4 for the absorber.
Header 1 provided on the upper part of the same tube sheet via A
Outflow from 1.

FIG. 7 is a cross sectional view showing another example in which the heat exchanger of the present invention is used in an absorption refrigerator. The end of the heat transfer tube for the absorber and the end of the heat transfer tube for the condenser are installed in the same direction. Here is an example: In FIG. 7, the heat transfer tube unit 4 for the absorber is attached to the left tube sheet 2.
A and the condenser heat transfer tube unit 4C are joined. On the other hand, to the right tube plate 2, an evaporator heat transfer tube unit 4E and a regenerator heat transfer tube unit 4G are joined. With this arrangement, the cooling water flowing through the absorber and the condenser can be configured by the common header 11. The heat fluid flows into the regenerator heat transfer tube unit 4G from the header 12, flows in the heat transfer tube 3, and flows out from the upper header of the same tube sheet. The illustrated embodiment is not limited to the single-effect absorption refrigerator and is naturally applicable to the multiple-effect absorption refrigerator and the absorption chiller-heater. Further, the evaporator, the absorber, the regenerator, and the condenser can be housed in an integral shell or in a twin shell shell.

[0016]

EFFECTS OF THE INVENTION According to the present invention, the heat transfer tubes are brought into close contact with each other, so that the heat transfer tubes can be made compact and the ends of the tubes can be easily fixed, and an ordinary circular tube or the like can be used as the heat transfer tube. It was possible to obtain a heat exchanger that is reliable in terms of strength. Furthermore, the liquid flow in the horizontal direction was promoted on the close surface of the heat transfer tube, and as a result, a uniform liquid film was formed on the heat transfer surface, and a high performance heat exchanger could be obtained. Also,
Using the heat exchanger of the present invention, a compact and high-performance absorption refrigerator can be provided.

[Brief description of drawings]

FIG. 1 is a plan view of a cross-sectional configuration diagram showing an example of a heat exchanger of the present invention.

FIG. 2 is a cross-sectional configuration diagram showing another example of the heat exchanger of the present invention, (a) is a front view, (b) is a cross-sectional view of the binding member 23 in (a), and (c) is a pipe end portion. Side view showing (a), (d) is (a)
2 is a cross-sectional view taken along line XX of FIG.

FIG. 3 is a cross-sectional configuration diagram showing an example in which the heat exchanger of the present invention is used in an absorption refrigerator.

FIG. 4 is a cross-sectional configuration diagram showing another example in which the heat exchanger of the present invention is used in an absorption refrigerator.

5 is a cross-sectional configuration diagram of a side surface viewed from the right direction in FIG.

6 is a cross-sectional configuration diagram viewed from the front side of FIG.

FIG. 7 is a cross-sectional configuration diagram showing another example in which the heat exchanger of the present invention is used in an absorption refrigerator.

[Explanation of symbols]

1: Shell, 2: Tube plate, 3: Heat transfer tube, 4, 4A, 4C,
4E, 4G: Heat transfer tube units 5, 5A, 5E, 5G:
Liquid spraying device, 6: Eliminator, 7: Collector, 8: Cold water inlet, 9: Cooling water inlet, 10: Cold water header, 11: Cooling water header, 12: Heating fluid header, 20: Guide member, 21: Extraction air Piping, 22: extraction hole, 23: binding member, 30: partition wall

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F25B 39/04 F25B 39/04 Q 43/04 43/04 A F28F 13/18 F28F 13/18 B (72 ) Inventor Ken Ishiyama 11-1 Haneda-Asahi-cho, Ota-ku, Tokyo Inside the EBARA CORPORATION (72) Inventor Toshio Matsubara 11-11 Haneda-Asahi-cho, Ota-ku, Tokyo Inside the EBARA CORPORATION (72) Inventor Ito No. 11-1 Haneda-Asahi-cho, Ota-ku, Tokyo (72) Inventor, Ekuha Co., Ltd. Kikuichi Mori 11-11 Haneda-Asahi-cho, Ota-ku, Tokyo (72) Inventor, Koichi Kunimasa Tokyo 11-1 Haneda-Asahi-cho, Ota-ku Inside the EBARA CORPORATION (72) Inventor Hiroshi Ishii 11-11 Haneda-Asahi-cho, Ota-ku, Tokyo Inside the EBARA CORPORATION (72) Yuko Imoto Ota-ku, Tokyo TaAsahi cho No. 11 No. 1 Ebara Corporation in the F-term (reference) 3L093 BB00 MM02 MM07 3L103 AA05 AA36 AA40 BB42 DD06 DD10 DD42 DD44 DD87

Claims (6)

[Claims] 1. A heat transfer tube having a shape that is bent so that the flow direction is reversed in the middle part of the heat transfer tube, and the bent shape of the middle part is sequentially changed so that the heat transfer tubes are in close contact with each other on the upper surface and the lower surface. Between a plurality of heat transfer tubes that are vertically stacked to form a heat transfer tube unit, and the heat transfer tube units are horizontally arranged at a predetermined interval between the fluid inside the heat transfer tube and the fluid outside the heat transfer tube. A heat exchanger for exchanging heat, wherein both ends of the heat transfer tube are joined to a tube plate or a header for a fluid in the tube, the shape of both ends of the heat transfer tube is circular, and an intermediate portion other than both ends of the heat transfer tube is formed. A heat exchanger having a structure in which a portion is an elliptical shape that is long in the vertical direction or a substantially rectangular shape, and the height dimension in the vertical direction in the middle portion is larger than the outer diameter of both ends. 2. The heat exchanger according to claim 1, wherein an outer surface of the heat transfer tube is subjected to hydrophilic treatment for improving wettability. 3. The heat transfer tube unit is provided with positioning guide members on the upper surface of the uppermost heat transfer tube and the lower surface of the lowermost heat transfer tube forming the unit, and each heat transfer tube forming the heat transfer tube unit. The heat exchanger according to claim 1 or 2, further comprising a binding member for binding the guide member. 4. An evaporator, an absorber, which constitutes an absorption refrigerator,
An absorption refrigerator comprising the heat exchanger according to claim 1, 2 or 3 for at least one of a regenerator and a condenser. 5. The absorption refrigerating machine according to claim 4, wherein the heat exchanger is used as it is for a condenser, or for an evaporator by providing a refrigerant spraying device on an upper part of the heat transfer tube unit, or a heat transfer tube unit. An absorption refrigerating machine, which is provided with a device for spraying an absorption solution on the upper part thereof and is used for one or more of an absorber and a regenerator. 6. The absorption refrigeration system according to claim 4 or 5, wherein the heat transfer tube unit of the heat exchanger is provided with a pipe for extracting non-condensable gas in an intermediate space in the vertical direction of the unit. Machine.