JP2989128B2 - Absorption refrigeration system with heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger of an absorption refrigeration system using an aqueous solution such as lithium bromide as an absorbing solution.

[0002]

2. Description of the Related Art In an absorption refrigeration system, an aqueous solution (absorbing liquid) of lithium bromide or the like having a low concentration is heated and boiled by a high-temperature regenerator to form a solution (refrigerant) such as water and a medium-concentration absorbing liquid (absorbing liquid). Medium concentration lithium bromide aqueous solution). Further, the refrigerant is re-evaporated from the medium-concentration absorbent in the low-temperature regenerator to generate a high-concentration absorbent. The refrigerant is liquefied in a condenser provided with a cooling coil, is supplied to a low-pressure evaporator, and evaporates by removing heat of evaporation from the evaporation coil disposed in the evaporator. The high-concentration absorbent is guided to an absorber provided with a cooling coil and dropped on the cooling coil, and then absorbs the evaporated refrigerant to become a low-concentration absorbent, and is returned to the high-temperature regenerator by a pump.

The low-concentration absorbent returning to the high-temperature regenerator has a low temperature, the high-concentration absorbent supplied to the absorber has a medium temperature, and the medium-concentration absorbent supplied to the low-temperature regenerator has a high temperature. I have. From the viewpoint of thermal efficiency, it is desirable that the absorption liquid having a low concentration be as high as possible and the absorption liquid having a high concentration be as low as possible.

[0004] Therefore, the absorption refrigeration system is provided with a heat exchanger for exchanging heat between the high-concentration or middle-concentration absorbent and the low-concentration absorbent to improve the thermal efficiency. As this heat exchanger, a plate-type heat exchanger in which a large number of plates are stacked in a casing and a large number of internal passages are arranged inside is usually used.

[0005]

In this heat exchanger, the low-concentration absorbing liquid flowing out of the low-concentration absorbing liquid inlet into the heat exchanger by a pumping means such as a pump is arranged in multiple layers in the heat exchanger. Of the many low-concentration absorbent flow paths inside the vessel, the flow tends to flow far from the low-concentration absorbent inlet, and it is difficult to evenly supply the low-concentration absorbent liquid. As a result, the distribution of the flow rate becomes uneven among the low-concentration absorbent flow paths arranged in the vessel, the heat exchange amount per unit area becomes uneven, and the heat exchange efficiency of the entire heat exchanger is reduced. There is a problem.

An object of the present invention is to provide a plate heat exchanger in which a plurality of low-concentration absorbent flow paths are arranged in parallel.
It is an object of the present invention to provide a heat exchanger for an absorption refrigeration system that can uniformly flow a low-concentration absorbent in each vessel.

[0007]

SUMMARY OF THE INVENTION The present invention provides a heating source, a heating tank for boiling a low-concentration absorbing liquid by the heating source and separating the refrigerant into a medium-concentration absorbing liquid, and a refrigerant recovery tank for recovering evaporated refrigerant. A high-temperature regenerator, a low-temperature regenerator that re-boils the medium-concentration absorbent using the refrigerant recovery tank as a heat source, and separates the refrigerant vapor and the high-concentration absorbent into refrigerant, the refrigerant generated by the high-temperature regenerator and the low-temperature regenerator. A refrigerator body comprising a condenser for condensing, an evaporator for evaporating the condensed refrigerant liquid to cool the cold / hot water for a cold heat source, and an absorber for absorbing the evaporated refrigerant vapor into a high-concentration absorbent, and the absorber A heat exchanger for exchanging the low-concentration absorbent discharged from the medium with the medium-concentration absorbent or the high-concentration absorbent, wherein the heat exchanger has a flow path in a casing. For forming A plurality of in-vessel low-concentration absorbent flow paths for laminating the rate and flowing the low-concentration absorbent are arranged side by side, and an inlet pipe is provided above the casing, and substantially all the plates are arranged in the juxtaposition direction in the casing. It is characterized by being provided with an outlet to each of the low-concentration absorbing liquid flow paths in each vessel on the outer peripheral surface of the inlet pipe.

[0008] In the structure according to the second aspect of the present invention, there is provided a heating source, a heating tank for boiling the low concentration absorbing liquid by the heating source to separate the refrigerant into a medium concentration absorbing liquid, and a refrigerant collecting tank for collecting the evaporated refrigerant. A high-temperature regenerator, a low-temperature regenerator that re-boils the medium-concentration absorbent using the refrigerant recovery tank as a heat source to separate refrigerant vapor and a high-concentration absorbent, and condenses the refrigerant generated by the high-temperature regenerator and the low-temperature regenerator And a high-temperature regenerator comprising an evaporator, an evaporator for evaporating condensed refrigerant liquid to cool the cold and hot water for a cold heat source, and an absorber for absorbing the evaporated refrigerant vapor into a high-concentration absorbent. The medium-concentration absorbent generated in the above, passed through a medium-concentration absorbent heat exchanger, heat-exchanged with the low-concentration absorbent discharged from the absorber, and then guided to the low-temperature regenerator, The low temperature regeneration The high-concentration absorbent produced in the above, passed through a high-concentration absorbent heat exchanger, heat-exchanged with the low-concentration absorbent discharged from the absorber, and then guided to the absorber, the high-concentration absorbent flow path, The low-concentration absorbent discharged from the absorber is heat-exchanged with the medium-concentration absorbent and the high-concentration absorbent by the high-concentration absorbent heat exchanger and the medium-concentration absorbent heat exchanger, and is pumped by the absorbent pump. And a low-concentration absorbent flow path for returning to the high-temperature regenerator, the medium-concentration absorption liquid heat exchanger or the high-concentration absorption liquid heat exchanger includes a flow path for forming a flow path in a casing. A plurality of low concentration absorbent flow paths in the vessel are arranged in parallel to flow the low concentration absorbent in the vertical direction by laminating the plates, and an inlet pipe is provided in the casing in a substantially upper part of the casing in the direction in which the low concentration absorbent flows in the casing. And insert it through the plate Moni, characterized in that the formation of the low concentration absorption solution inlet formed by providing the outlet port to the the outer circumferential surface of the inlet pipe each vessel in the low concentration absorption solution flow path.

According to the third aspect of the present invention, the high-concentration absorbent heat exchanger and the intermediate-concentration absorbent heat exchanger are provided vertically in the same vertically long casing, and the low-concentration absorbent heat exchanger is provided inside the casing. The absorbent flow path has a low-concentration absorbent inlet at an upper end of the casing and a low-concentration absorbent outlet at a lower end, and is formed along the entire length of the casing. A middle concentration absorbing liquid inlet, a middle concentration absorbing liquid outlet in the middle, and formed along the middle from the lower end of the casing; the high concentration absorbing liquid flow path has a high concentration absorbing liquid inlet in the middle of the casing; And a high-concentration absorbent outlet formed along the middle to upper end of the casing.

According to a fourth aspect of the present invention, in the heat exchanger of the absorption refrigeration apparatus, the outlet is an axial slit formed in the inlet pipe.

[0011]

In the heat exchanger of the absorption refrigeration system, the outlet for discharging the low-concentration absorbent into the low-concentration absorbent flow passage in the heat exchanger is provided in the heat exchanger. It is provided on the outer peripheral surface of the inlet pipe inserted in the juxtaposed direction. The low-concentration absorbent is first filled in the inlet pipe by the flow path resistance of the outlet, and is discharged from each outlet to the low-concentration absorbent flow path in each vessel. For this reason, the amount of the low-concentration absorbing liquid supplied to each low-concentration absorbing liquid flow path in each vessel can be distributed substantially evenly.

According to the third aspect of the present invention, the heat exchanger for high-concentration absorbent and the heat exchanger for medium-concentration absorbent are integrated, so that the mountability can be improved. According to the configuration of the fourth aspect, it is possible to easily form the outlet.

[0013]

1 to 3 show a heat exchanger H in which a high-concentration absorbent heat exchanger and a medium-concentration absorbent heat exchanger are integrated, and a refrigerator main body 200 of an absorption refrigerating apparatus 100 shown in FIG. And it is attached to the refrigerator main body 200. Refrigerator body 2
Reference numeral 00 denotes a vertical cylindrical shape, and the heat exchanger H has a vertically long and flat box shape, is vertically fastened to the outer wall surface of the refrigerator main body 200, and is housed on one side of the housing A. On the other side of the housing A, a cooling tower (cooling tower) shown in FIG.
The CT and the cooling blower CB are accommodated.

As shown in FIG. 5, the absorption refrigeration system 100 includes a refrigerator main body 200 and a cooling tower (cooling tower).
An indoor unit CU is additionally provided to constitute a cooling / heating device. The absorption refrigeration apparatus 100 includes a high-temperature regenerator 1 for heating and boiling a low-concentration absorbent and separating it into a medium-concentration absorbent and refrigerant vapor.

The high-temperature regenerator 1 includes a heating tank 11 in which a gas burner B as a heating source is disposed below,
A medium-concentration absorbent partition 12 which is a cylinder extending upward from 1 and having an open upper end; and a refrigerant recovery tank 10 which is a vertical cylindrical container disposed on the outer periphery of the medium-concentration absorbent partition 12. .

The medium-concentration absorbing liquid partition 12 has a medium-concentration absorbing liquid having a medium concentration due to evaporation of refrigerant in the lower portion 121, and an absorbing liquid (refrigerant vapor) boiling from an upper end opening 122.
Blows out into the refrigerant recovery tank 10. On the outer periphery of the refrigerant recovery tank 10, a low-temperature regenerator 2 having an action of improving the thermal efficiency of the absorption refrigeration apparatus 100 is provided.

The low-temperature regenerator 2 has a vertical cylindrical shape, and includes a low-temperature regenerator case 20 having a refrigerant vapor outlet 21 opened in the ceiling. In the low-temperature regenerator case 20, heat is passed from the lower part 121 of the intermediate-concentration absorbent partition 12 through the lower half of the heat exchanger H (intermediate-concentration absorbent heat exchanger part) by the intermediate-concentration absorbent flow path L1. The exchanged medium concentration absorption liquid is supplied. The medium concentration absorbing liquid is re-evaporated using the outer peripheral surface of the refrigerant recovery tank 10 as a heat source, and is separated into a high concentration absorbing liquid and refrigerant vapor.

On the outer periphery of the low-temperature regenerator 2, an airtight and vertical cylindrical evaporation / absorption case 30 is installed concentrically. An absorber 3 is provided in the evaporation / absorption case 30, and an evaporator 4 is provided on the outer periphery of the absorber 3. An airtight, vertical cylindrical condenser case 50 is installed concentrically on the outer periphery of the low-temperature regenerator 2 and above the evaporating / absorbing case 30, and a condenser 5 in which a cooling coil 51 is disposed.
Is provided.

The absorber 3 is provided with a cooling coil 31 wound in a vertical cylindrical shape inside the evaporating / absorbing case 30 and for spraying the high-concentration absorbing liquid to the cooling coil 31 above the cooling coil 31. A high-concentration absorbent sprayer 32 is attached. The evaporator 4 has an evaporator coil 41 wound in a vertical cylindrical shape disposed on an outer portion inside the evaporator / absorber case 30, and a refrigerant liquid disperser 42 disposed above the evaporator coil 41.

A high-temperature regenerator 1, a low-temperature regenerator 2, an absorber 3,
The evaporator 4 and the condenser 5 are arranged concentrically and are integrally welded to form a vertical cylindrical refrigerator main body 200 as shown in FIG. The refrigerator main body 200 is
It is supported by the stand 201 and vertically erected inside the housing A.

Between the bottom of the absorber 3 and the bottom of the heating tank 11, the low-concentration absorbent discharged from the absorber 3 is passed through the entire portion from the upper end to the lower end of the heat exchanger H, and then heated to a high temperature. It is connected by a low concentration absorbent flow path L2 for returning to the heating tank 11 of the regenerator 1. Low concentration absorbent flow path L
2 is provided with an absorbent pump P1 for circulating a low concentration absorbent.

The upper part of the low-temperature regenerator 2 is a gas-liquid separator 22. The gas-liquid separator 22 is separated from the upper part of the condenser 5 by a gap 5.
It communicates via A. The lower part 121 of the intermediate-concentration absorbent partition 12 is connected to the low-temperature regenerator 2 through the medium-concentration absorbent flow path L1.
Communicate with the top or bottom (the top in the figure).

A refrigerant liquid receiving portion 10a is provided between the refrigerant recovery tank 10 and the medium-concentration absorbent partition 12 and communicates with the condenser 5 through a refrigerant flow path L3. The refrigerant liquid is sucked by the low pressure in the condenser case 50 and supplied to the condenser 5. A part of the refrigerant liquid flowing into the condenser 5 is vaporized by the low pressure, but the vaporized refrigerant is cooled and condensed by the cooling coil 51 together with the refrigerant of the low-temperature regenerator supplied from the gap 5A.

The high concentration absorbent receiving portion 23 of the low temperature regenerator 2
Is connected to the high-concentration absorbent spraying device 32 of the absorber by a high-concentration absorbent flow path L4. The high-concentration absorbent is sucked by the low pressure in the evaporating / absorbing case, passes through the upper half of the heat exchanger H (the high-concentration absorbent heat exchanger part) and is heat-exchanged, and then to the high-concentration absorbent sprayer 32. Supplied.

The lower part of the condenser 5 and the evaporator coil 4 of the evaporator 4
The refrigerant liquid dispersing device 42 installed above the first liquid container 1 communicates with the refrigerant liquid supply passage L5. The refrigerant is sprayed on the surface of the evaporating coil 41 from the refrigerant liquid sprayer 42, evaporates by removing the heat of vaporization from the evaporating coil 41, cools cold and hot water as a heat medium flowing inside, and absorbs the cooling coil of the absorber 3. The high concentration absorbing liquid dropped from the high concentration absorbing liquid spraying tool 32 on the surface of 31 absorbs the liquid. Absorbing liquid that has become low concentration by absorbing refrigerant,
The heat is returned to the heating tank 11 by the low concentration absorbent flow path L2.

The cooling coil 31 is connected to the cooling coil 51, and further connected to the cooling tower CT via the cooling water circulation path 33. The cooling water is supplied by the cooling water pump P2 to the cooling tower CT → the cooling coil 31 → the cooling coil 51 → It circulates in the order of the cooling tower CT. The evaporating coil 41 is connected to the indoor unit CU through a cold / hot water circulation path 43 having a cold / hot water pump P3.

As shown in FIGS. 1 to 3, the heat exchanger H has a vertically elongated casing 6 having a rectangular cross section, and brackets 60, 60 welded to the side surfaces of the casing 6 are provided on the outer wall surface of the refrigerator main body 200. 202 is fastened with a fastener. The casing 6 is composed of a press-formed container-shaped main body 61 and a press-formed lid 63 around which a fitting edge 62 is provided. The cover 63 is fitted into the main body 61 and the fitting surface is welded.

In the main body 61, a large number of plates 64 formed by press forming and provided at predetermined positions with an opening 64a for entrance, an opening 64b for exit, and irregularities 64c for forming a partitioned flow path for the absorbent. Are fitted into each plate 64, 6
A flow path for the absorbing liquid is formed between the four. In the formed absorbent flow path, two kinds of absorbents which are alternately different, that is, a high-concentration absorbent and a low-concentration absorbent flow in the upper half, and a medium-concentration absorbent and a low-concentration absorbent flow in the lower half. . The lid 63 is provided with a low-concentration absorbent inlet 71 at the left corner of the outer surface of the upper end and an outlet 72 for the low-concentration absorbent at the right corner of the lower end. An absorbent flow path L2 is provided.

At the lower end of the lid 63, a medium-concentration absorbing liquid inlet 73 is provided on the left side, and on the right side of the intermediate part, a medium-concentration absorbing liquid outlet 74 is provided. A flow path L1 is provided. A high-concentration absorbent inlet 75 is formed on the left side of the middle part of the lid 63, and a high-concentration absorbent outlet 76 is formed on the right side of the upper end part. L4 is provided.

That is, in this embodiment, the casing 6
The upper half is a high-concentration absorbent heat exchanger, and the lower half is a medium-high-absorbent liquid heat exchanger. As in this embodiment, the configuration in which the heat exchange between the low-concentration absorbing solution, the medium-concentration absorbing solution and the high-concentration absorbing solution is performed by one heat exchanger H uses two independent heat exchangers. There is an advantage that piping can be simplified as compared to

FIG. 6 shows a change in temperature of the absorbing liquid that is heat-exchanged in the heat exchanger H. The low-temperature, low-concentration absorbent discharged from the absorber 3 is supplied to the heat exchanger H by the absorbent pump P1, and heat-exchanged with the high-concentration absorbent and the medium-concentration absorbent to be heated. It returns to 11 and is heated again and boils. The medium-concentration absorbent in the medium-concentration absorbent partition 12 has a high temperature, is heat-exchanged with the low-concentration absorbent in the heat exchanger H, is cooled, and then supplied to the low-temperature regenerator by a pressure difference. The high-concentration absorbent generated in the low-temperature regenerator 2 is cooled by heat exchange with the low-concentration absorbent in the heat exchanger H, and is supplied to the high-concentration absorbent sprayer 32 with a pressure difference.

As shown in FIG. 1, the low-concentration absorbing liquid inlet 71 serves as an outlet for the low-concentration absorbing liquid into the heat exchanger H, and is connected to each low-concentration absorbing liquid passage formed between the plates 64, 64. An inlet pipe 8 provided with an axial slit 81 is formed to penetrate substantially all the plates 64 so as to communicate with each other. The inlet pipe 8 is set to be substantially horizontal, and the slits 81 are divided by the plate 64 at substantially the same level and in the same area, and a large number of low-concentration absorbing liquid flows provided in the heat exchanger H are provided. It is an outflow hole 82 to the road 83.

The low-concentration absorbing liquid is discharged by the absorbing liquid pump P 1, is fed under pressure to the upper part of the heat exchanger H, reaches the inlet pipe 8, and falls from the outlet holes 82 into the heat exchanger H. At this time, the inlet pipe 8 is disposed horizontally, and the outflow holes 82 have substantially the same width and the same level at the edges, and the total area of the outflow holes 82 is narrowed. After the pressure-fed low-concentration absorbing liquid fills the inlet pipe 8 due to the flow path resistance of the outflow hole 82, an approximately equal amount of the low-concentration absorbing liquid can be supplied to the low-concentration absorbing liquid flow path 83 in each device.

Therefore, the heat exchange with the high-concentration absorbing solution or the medium-concentration absorbing solution in the heat exchanger H is efficiently performed. The outflow hole 82 is provided with a low-concentration absorbent flow path 83 in each unit in the heat exchanger H.
May be the same size and the same level of hole row formed corresponding to the above, but by employing the slit 81,
Since a large number of outflow holes 82 of the same size and the same level can be formed, the processing labor is reduced.

In the above embodiment, the heat exchanger H is of a vertical type, and the low-concentration absorbent flow path 83 in the heat exchanger H is formed vertically, so that the inlet pipe 8 is set to be substantially horizontal. The heat exchanger may be of a horizontal type that is long in the horizontal direction. In this case, the inlet pipe 8 is set in the side-by-side direction of the low-concentration absorbent flow path 83 in the heat exchanger.

In the above embodiment, the outflow holes 82 are formed in the same area for each of the low-concentration absorbent flow paths 83 in the heat exchanger H. However, the discharge amount of the absorbent pump P1 tends to be large. In this case, the outlet pipe 82 on the tip end side of the inlet pipe 8 (lower-concentration absorbent flow path in the heat exchanger on the back side) may have a smaller area to achieve uniformity. Further, the low-concentration absorbing liquid may be pumped using a pumping means other than the pump. As a heating source, another heat source such as an electric heater may be used instead of the burner B.

[Brief description of the drawings]

FIG. 1 is a sectional view of a heat exchanger.

FIG. 2 is a front view of the heat exchanger.

FIG. 3 is a side view of the heat exchanger.

FIG. 4 is a perspective view of an absorption refrigeration apparatus.

FIG. 5 is a configuration diagram of an absorption refrigeration apparatus.

FIG. 6 is a graph showing a heat exchange action by a heat exchanger.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Absorption refrigeration apparatus 200 Refrigerator main body 1 High temperature regenerator 2 Low temperature regenerator 3 Absorber 4 Evaporator 5 Condenser H Heat exchanger 6 Casing 61 Container-shaped main body 63 Lid 64 Plate 76 High-concentration absorbent outlet 8 Inlet pipe 81 Slit 82 Outflow hole 83 Low-concentration absorption liquid flow path in vessel

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsutomu Maruhashi 2-26, Fukuzumi-cho, Nakagawa-ku, Nagoya-shi Inside Rinnai Corporation (72) Inventor Satoshi Naito 916 Kuramatsucho, Hamamatsu-shi, Shizuoka Pref. (72) Inventor Norio Uenoden 4-1-2, Hirano-cho, Chuo-ku, Osaka City Inside Osaka Gas Co., Ltd. (72) Inventor Kaoru Watanabe 2-49, Numame, Isehara City, Kanagawa Prefecture, Japan 56) References JP-A-7-190650 (JP, A) JP-A-2-147766 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F25B 15/00 303 F28F 3 / 08 311

Claims (4)

(57) [Claims] 1. A high-temperature regenerator having a heating source, a heating tank for boiling a low-concentration absorbing liquid by the heating source to separate the refrigerant into a medium-concentration absorbing liquid, and a refrigerant recovery tank for recovering the evaporated refrigerant. A low-temperature regenerator that re-boils the medium-concentration absorbent using a tank as a heat source to separate refrigerant vapor and a high-concentration absorbent, a condenser that condenses the refrigerant generated by the high-temperature regenerator and the low-temperature regenerator, An evaporator for evaporating the refrigerant liquid to cool the cold / hot water for a cold heat source, a refrigerator body comprising an absorber for absorbing the evaporated refrigerant vapor into a high-concentration absorbent, and a low-concentration absorbent discharged from the absorber A heat exchanger for exchanging heat with the medium-concentration absorbing solution or the high-concentration absorbing solution, wherein the heat exchanger is formed by laminating a flow path forming plate in a casing, Concentration A plurality of in-vessel low-concentration absorbent flow paths for flowing liquid are arranged side by side, and an inlet pipe is inserted into the casing through substantially all of the plates in the juxtaposed direction in the upper side of the casing. An absorption refrigeration apparatus comprising an outlet on the outer peripheral surface of a pipe to each of the low-concentration absorbent flow paths in each vessel. 2. A high-temperature regenerator having a heating source, a heating tank for boiling the low-concentration absorbing liquid by the heating source to separate the refrigerant into a medium-concentration absorbing liquid, and a refrigerant recovery tank for recovering the evaporated refrigerant. A low-temperature regenerator that re-boils the medium-concentration absorbent using a tank as a heat source to separate refrigerant vapor and a high-concentration absorbent, a condenser that condenses the refrigerant generated by the high-temperature regenerator and the low-temperature regenerator, An evaporator that evaporates the refrigerant liquid to cool the cold / hot water for the cold heat source, and a refrigerator body that includes an absorber that absorbs the evaporated refrigerant vapor into the high-concentration absorbent, and a medium-concentration absorbent generated by the high-temperature regenerator. Was passed through the medium-concentration absorbent heat exchanger, heat-exchanged with the low-concentration absorbent discharged from the absorber, and then passed to the low-temperature regenerator, and the medium-concentration absorbent flow path was generated by the low-temperature regenerator. High concentration absorption liquid A high-concentration absorbent flow path that passes through a high-concentration absorbent heat exchanger and exchanges heat with a low-concentration absorbent discharged from the absorber, and then leads to the absorber; and a low-concentration absorbent that is discharged from the absorber. The absorption liquid is heat-exchanged with the medium-concentration absorption liquid and the high-concentration absorption liquid by the high-concentration absorption liquid heat exchanger and the medium-concentration absorption liquid heat exchanger, and is pumped by the absorption liquid pump and returned to the high-temperature regenerator. An absorption refrigeration system having a low-concentration absorbent flow path and a medium-concentration absorption liquid heat exchanger or a high-concentration absorption liquid heat exchanger, A plurality of low-concentration absorbent flow paths in which the low-concentration absorbent flows are arranged in parallel, and an inlet pipe is inserted into the casing through substantially all of the plates in the juxtaposition direction, above the casing. Outside the inlet pipe An absorption refrigeration apparatus, wherein a low-concentration absorbent inlet is provided on an outer peripheral surface thereof, the outlet being provided to each of the low-concentration absorbent flow paths in each vessel. 3. The low-concentration absorbent according to claim 2, wherein the high-concentration absorbent heat exchanger and the medium-concentration absorbent heat exchanger are provided vertically in the same vertically-long casing. The flow path has a low-concentration absorbent inlet at an upper end of the casing and a low-concentration absorbent outlet at a lower end and is formed along the entire length of the casing, and the medium-concentration absorbent flow path is formed at a lower end of the casing. A concentration-absorbing liquid inlet, a medium-concentration absorbing liquid outlet in the middle, and formed along the middle from the lower end of the casing; the high-concentration absorbing liquid flow path has a high-concentration absorbing liquid inlet in the middle of the casing; An absorption refrigerating apparatus having a concentration absorbing liquid outlet and formed along the middle to the upper end of the casing. 4. The absorption refrigeration system according to claim 1, wherein the outlet is an axial slit formed in the inlet pipe.