JPH0571827A - Absorption freezer - Google Patents

Abstract

PURPOSE:To reduce fluid resistance of steam in the absorber or the vaporizer of an absorption freezer and to facilitate discharge of non-condensable gas at the absorber. CONSTITUTION:Heat transfer pipe arrangement of an absorber or a vaporizer is divided, as seen from the longitudinal direction of a heat transfer pipe, into a plurality of pipe group blocks divided by means of a steam flow passage. The fluid distance of steam in the pipe group is shortened and incurring of a pressure loss is reduced. Steam from the vaporizer flows in after the flow of it through a steal inflow part 4. Simultaneously with spread of the steam over the whole of the interior of the absorber after the flow of it through a steam flow passage 3, the steam is absorbed by means of absorption liquid 6 sprayed over the outer surface of each heat transfer pipe through a spraying device 5. A plurality of pipe group blocks where the heat transfer pipes 1 are densely arranged are surrounded with the steam flow passage 3 and fluid resistance of the steam can be reduced. A pipe group block 10 adjoining to an absorption liquid discharge port or an extraction port 7 is formed such that the number of heat transfer pipes is higher than that of other pipe group block or has a pipe pitch narrower than that of other pipe group block. A pressure therein is reduced and discharge of non-condensable gas is facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigerator used for cooling and heating, and more particularly to a heat transfer tube array of an absorber and an evaporator and a dispersion plate installed in a heat transfer tube group.

[0002]

2. Description of the Related Art Generally, an absorption refrigerator has an evaporator, an absorber,
Low-temperature regenerator, high-temperature regenerator, and pumps that connect them,
It consists of a heat exchanger. FIG. 9 is a systematic diagram of the principle. Water is passed through the pipes of the pipe group in the evaporator,
Water is sprayed as a refrigerant to the outside of the tube, and the latent heat of vaporization cools the water in the tube to supply it as cold water to a cooler or the like.
The water vapor evaporated in the evaporator flows into the absorber and is absorbed by the absorbing liquid (lithium bromide solution, etc.) scattered on the outer surface of the tube group in the absorber, and the absorption heat generated at this time is the cooling water passing through the inside of the pipe. Cooled by. The concentration of the absorbing liquid that has absorbed the water vapor in the absorber decreases, and the absorbing power becomes weak. Therefore, after preheating this through a heat exchanger, it is sent to a high-temperature regenerator and a low-temperature regenerator to be heated and concentrated. As a heat source of the high temperature regenerator, it is general to use heat generated by burning gas, oil or the like. The steam generated in the high temperature regenerator is used as the heat source of the low temperature regenerator. The steam generated in the low temperature regenerator and the high temperature regenerator is finally cooled by the cooling water in the condenser and condensed. The condensed water is supplied to the evaporator as an evaporation medium.

Of the constituent elements of the absorption refrigerator, the absorber and the evaporator are particularly important in that they affect the performance of the absorption refrigerator.

The evaporator cools the cooling medium such as water with the latent heat of the evaporation medium such as water as described above. The evaporator is mainly composed of a zigzag or grid array of heat transfer tubes and a spraying device for spraying the evaporation medium on the surface thereof. Generally, water is passed as a cooling medium in the heat transfer tube, and the water scattered on the outer surface of the heat transfer tube is
Since the inside of the system is kept at a low pressure, it evaporates, and the latent heat thereof cools the water flowing in the heat transfer tube and is used for cooling or the like. The vapor generated in this evaporator is guided to the absorber as described above. Like the evaporator, the absorber mainly includes a zigzag or lattice arrangement of heat transfer tubes and a spraying device for spraying the absorbing liquid on the surface thereof. Generally, a lithium bromide solution is used as the absorbing liquid, and the absorbing liquid is sprayed on the outer surface of the heat transfer tube. The vapor pressure of lithium bromide is much smaller than that of water, and the vapor flowing from the evaporator to the absorber is absorbed by the absorbing liquid based on the vapor pressure difference. At that time, since the temperature of the absorbing liquid rises due to the absorbed heat, a cooling medium such as water is made to flow in the heat transfer tube for cooling.

In order to improve the performance of the absorption refrigerator, it is necessary to increase the effective pressure difference between the vapor pressure of the vaporizing medium in the evaporator and the vapor pressure of the absorbing liquid in the absorber, based on the above-mentioned operation principle of the absorption cycle. There is. For that purpose, firstly, the flow resistance (pressure loss) of the vapor in the tube group of the absorber and the evaporator is made small, and the pressure difference available for absorbing the vaporization in the absorber is made large. .. The second is to improve the absorption heat transfer characteristics in the absorber. To that end, there are three main measures. One measure is not directly related to the present invention, but in order to improve absorption heat transfer characteristics of a single heat transfer tube, fins are formed on the surface of the heat transfer tube as described in JP-A-63-6363, and The purpose is to increase the holding area of the absorbing liquid while increasing the heat area. Another measure is to prevent the accumulation of non-condensable gas such as air, which becomes a heat transfer resistance on the steam side. Another measure is to evenly supply and disperse the absorbing liquid to each heat transfer tube in the absorber to eliminate useless heat transfer tubes that are not used for absorption.

The conventional techniques for improving these performances are as follows:
As described in Japanese Patent No. 1187335, in the evaporator, the upstream portion of the steam is arranged in a heat transfer tube of a lattice arrangement with a narrow pitch, and the downstream portion with a large amount of steam flow is arranged in a staggered arrangement with a wide pitch, and in the absorber, There is a method of making the flow resistance of the steam uniform in the tube group by forming a zigzag arrangement with a wide pitch in the upstream part of the steam and a heat transfer tube group with a lattice arrangement with a narrow pitch in the downstream part of the steam. Further, as described in JP-A No. 62-155482, there is a method of preventing the noncondensable gas from accumulating and bleeding by providing a partition plate in the heat transfer tube group of the absorber in parallel with the tube row.

[0007]

In the above prior art, the heat transfer tube groups of the absorber and the evaporator have an integral structure, and all vapors must pass through the heat transfer tube group uniformly. In the evaporator, the steam generated in the upstream part of the steam flows across the heat transfer tube group to the steam outlet part. Further, in the absorber, the steam uniformly flows from the steam inlet portion to the steam downstream portion across the heat transfer tube group. That is, the passage distance of the steam heat transfer tube group is equal to the depth of the heat transfer tube group in the steam outflow direction in the evaporator and in the steam inflow direction in the absorber, and the flow resistance of the steam is generated accordingly. This increases the pressure loss in the heat transfer tube group and lowers the performance of the absorption chiller, and also limits the depth of the heat transfer tube group, which in turn limits the overall device configuration of the absorption chiller. Resulting in. Furthermore, in the absorber, the heat transfer tube near the steam inlet has a large amount of steam supply, so the absorption amount and heat transfer amount per unit heat transfer area increase, and the absorption amount decreases as going further into the heat transfer tube group. Will result in an imbalance. This does not make effective use of the heat transfer tube in the downstream portion of the steam in the absorber, and hinders the performance improvement of the absorber.

Further, in the absorber, a low-pressure portion is formed in the heat transfer tube group having an integral structure due to the flow resistance of vapor, and even if a partition plate is provided, the non-condensable gas stays in the low pressure portion, and absorption heat transfer occurs. Significantly reduces performance. On the other hand, the absorption liquid is supplied from the absorber by spraying or dripping from the uppermost part of the heat transfer tube group and gradually flowing down to the lower part while dripping the heat transfer tube group. In the case where the heat transfer tube is horizontal, the dripping absorption liquid is covered with steam, and the supply amount of the absorption liquid is remarkably reduced in a part of the heat transfer tubes in the lower part of the heat transfer tube group, so that the absorption heat transfer performance is deteriorated. A similar problem exists with the distribution of the evaporation medium of the evaporator.

Both of the above problems are closely related to the arrangement of the heat transfer tubes in the absorber or the evaporator, that is, the structure of the heat transfer tube group. The present invention is based on the idea that reduction of pressure loss (flow resistance of steam) in the heat transfer tube group leads to solution of all problems. First, the flow resistance of steam in the heat transfer tube group is reduced. However, by increasing the pressure difference that can be used for absorbing vapor in the absorber, the pressure distribution in the tube group is made uniform, the retention of noncondensable gas is suppressed, and It is an object of the present invention to form a low-pressure region in the vicinity of a bleeding port for bleeding to enable efficient bleeding of non-condensable gas.

[0010]

SUMMARY OF THE INVENTION In order to reduce the flow resistance of steam in a heat transfer tube group in an absorber, the absorber is not transferred to a conventional integrated tube group structure but is transferred to the absorber. The cross section viewed from the longitudinal direction of the heat tube is divided into a plurality of tube group blocks separated by a steam flow path. More specifically, the width of the steam flow passage in the cross section viewed from the longitudinal direction of the heat transfer tube is
An absorber having a tube arrangement in which the interval is larger than the maximum value of the interval between the adjacent heat transfer tubes in the tube group block in which the heat transfer tubes are densely arranged, and the plurality of tube group blocks are surrounded by the steam flow paths. Furthermore, more specifically, in a cross section of the absorber viewed from the longitudinal direction of the heat transfer tube, a plurality of tube group blocks are surrounded by a steam flow path having an interval larger than the maximum value of the interval between adjacent heat transfer tubes in the block, In addition, the tube group block in which the heat transfer tubes are densely arranged in the cross section viewed from the steam inflow surface to the absorber is divided by the steam flow path with a distance larger than the maximum value of the distance between the adjacent heat transfer tubes in the block. An absorber having a tube group. Depending on the shape of the absorber and the steam flow rate, the heat transfer tubes belonging to one tube group block are arranged so that the number of rows in the direction perpendicular to the steam inflow direction is 20 or less.

Further, in the absorber, in order to suppress the retention of the non-condensable gas in the heat transfer tube group and facilitate the extraction of the gas, the tube group block has the maximum value of the interval between the adjacent heat transfer tubes in the block. In an absorber having a tube group that is divided by steam passages with a larger spacing, the tube group block closest to the absorbing liquid discharge port or the noncondensable gas extraction port is a heat transfer tube compared to other tube group blocks. Use a large number or narrow heat transfer tube pitch.

[0012] In order to reduce the flow resistance of vapor in the heat transfer tube group in the evaporator, the evaporator is not the tube group structure of the conventional integral structure, but the longitudinal direction of the heat transfer tube, like the absorber. In the cross section as seen, the structure is divided into a plurality of tube group blocks separated by a steam flow path. More specifically, the width of the steam flow path in the cross section viewed from the longitudinal direction of the heat transfer tube is an interval larger than the maximum value of the interval between the adjacent heat transfer tubes in the tube group block in which the heat transfer tubes are densely arranged, In addition, the evaporator has a tube arrangement in which a plurality of tube group blocks are surrounded by a vapor flow path. Even more specifically, in a cross section of the evaporator seen from the longitudinal direction of the heat transfer tube, a plurality of tube group blocks are surrounded by steam flow paths having a spacing larger than the maximum value of the spacing between adjacent heat transfer tubes in the block, and Tubes in which a tube group block in which heat transfer tubes are densely arranged in a cross section viewed from the steam outflow surface from the evaporator is divided by steam flow paths with an interval larger than the maximum value of the interval between adjacent heat transfer tubes in the block Make an evaporator with groups. Depending on the shape of the evaporator and the steam flow rate, the number of rows of the heat transfer tubes belonging to one tube group block may be 20 or less in the direction perpendicular to the steam inflow direction.

In order to make the dispersion of the absorbing liquid in the absorber and / or the dispersion of the evaporation medium in the evaporator even in the lower part of the tube group, a dispersion plate that allows liquid and gas to simultaneously pass through the heat transfer tube group. Are placed horizontally. It is more effective if this dispersion plate is installed horizontally in the vapor flow path in an absorber or evaporator having a plurality of tube group blocks.

[0014]

According to the present invention, the vapor in the absorber or evaporator flows mainly through the vapor flow path and spreads throughout the absorber or evaporator. The flow resistance of the steam in the steam flow path is much smaller than the flow resistance in the tube group block in which the heat transfer tubes are densely arranged, and can be ignored. The vapor evaporated in the tube group block of the evaporator flows into the vapor flow path through the shortest distance in the tube group in the tube group block. Similarly, steam in the tube group block of the absorber flows into the tube group block from the steam flow path through the shortest distance in the tube group in the tube group block and is absorbed. In the conventional integrated tube group, the passage distance in the tube group when the steam flows in and out corresponds to the depth of the tube group in the steam flow direction. Therefore, in the present invention, since the passage distance of the steam in the tube group can be shortened, the flow resistance of the steam at that time can be greatly reduced. Since the pressure loss in the tube group can be reduced, the pressure distribution in the absorber or the evaporator can be made uniform, and the amount of vapor absorbed in each heat transfer tube in the absorber can be made uniform.

The uniform pressure distribution can suppress the retention of the non-condensable gas in the tube group block, and further, the vicinity of the extraction port or the non-condensable gas is discharged together with the absorbing liquid. In this case, the low-pressure region can be easily formed by increasing the number of tubes in the vicinity of the exhaust port as compared with other tube groups or by narrowing the heat transfer tube pitch, and non-condensing The sexual gas is attracted there and can be extracted efficiently.

The dispersion plate, which is arranged in the heat transfer tube group and allows the liquid and the gas to pass therethrough at the same time, once receives the absorbing liquid or the evaporation medium flowing down from the upper portion to the absorber or the evaporator without inhibiting the vapor flow. Redistribute. As a result, the absorbing liquid or the evaporating medium can be evenly supplied to the heat transfer tubes in the lower part of the vessel. This action is achieved by arranging the dispersion plate horizontally in the vapor passage in the absorber or evaporator having a plurality of tube group blocks because the absorbing liquid or the evaporating medium is covered in the vapor passage. Is even more effective.

[0017]

1 (1) and 1 (2) are schematic views of cross sections of two embodiments of an absorber of an absorption refrigerator according to the present invention as seen from the longitudinal direction of a heat transfer tube. DESCRIPTION OF SYMBOLS 1 is a heat transfer tube, 2 is a tube group block, 3 is a vapor flow path, 4 is an inflow part of vapor (steam) flowing from an evaporator, 5 is an absorbing liquid spraying device, 6 is an absorbing liquid, and 7 is an absorbing liquid discharge port. (This also serves as an extraction port in this embodiment). FIG. 1 (1) is an embodiment in which the steam generated in the evaporator flows horizontally through the steam inflow portion 4. The vapor inflow part 4 may be provided with an eliminator or the like in order to prevent the absorption liquid from scattering, but may be an opening in which nothing is provided. Four tube group blocks in which the heat transfer tubes 1 are densely arranged are formed in the absorber, and each tube group block is surrounded by the vapor flow path 3. The vapor flowing from the evaporator through the vapor inflow portion 4 reaches the entire inside of the absorber through the vapor flow path 3, and at the same time, is absorbed by the absorbing liquid scattered on the outer surface of each heat transfer tube. .. At that time, the absorption liquid is heated by the absorption heat, but is cooled by the cooling water flowing in the heat transfer tube. The absorbing liquid drips from the upper heat transfer pipe to the lower heat transfer pipe, and flows out of the absorber through the absorbing liquid discharge port 7. The absorbing liquid discharge port 7 may be provided with an extraction port for noncondensable gas such as air, or the ejector may discharge the noncondensing gas and absorbing liquid at the same time. In FIG. 1 (2), the vapor generated in the evaporator passes through the vapor inflow part 4 and flows in vertically from the upper part of the absorber. Similarly, in some embodiments, vapor may flow vertically from the bottom of the absorber to the top.

Next, the principle of the present invention will be described with reference to the results of numerical analysis of the basic tube group arrangement in the absorber. In this numerical analysis, the conservation law of mass and momentum is solved for the flow,
The amount of steam absorbed in the heat transfer tube group is calculated based on an empirical formula. For more information on this analytical model, see Proceeding of the
Second International Symposium on Condensers andco
It is based on the numerical analysis method shown in ndensation (1990), p.235-p.244. Figure 2 shows the numerical analysis
FIG. 3 is a cross-sectional view of a heat transfer tube group of a kind of absorber viewed from the longitudinal direction of the heat transfer tube. All three absorbers have the same volume (height 0.75 m, depth 0.33 m, heat transfer tube longitudinal direction 2.0).
m), and the number of heat transfer tubes arranged is equal to 336.
Steam flows in from the left side. In both cases, the arrangement of the heat transfer tubes (diameter 15.88 mm) is a staggered arrangement.
The "rectangular" array in (a) is a conventional tube bundle with an integral structure,
Horizontal tube pitch 23.3 mm in the heat transfer tube arrangement area 8,
The tubes are arranged at a vertical pipe pitch of 26.7 mm.
The “comb-shaped” arrangement of (b) is an arrangement in which the tube group blocks divided by the steam flow path are in contact with the inner wall surface of the absorber,
The horizontal pipe pitch is 17.0 mm and the vertical pipe pitch is 19.5 mm. The “block type” array of (c) is an array in which all the tube group blocks are surrounded by the steam flow paths, the horizontal tube pitch is 17.0 mm, and the vertical tube pitch is 19.5 mm. FIG. 3 shows the results of numerical analysis of the pressure distribution of steam at the pressure plot position 9 shown in FIG. 2 of these tube groups. From the analysis results, the pressure loss (difference between the pressure at the steam inlet and the pressure at the lowest pressure part) is obviously higher in the array divided into the tube group blocks than in the "rectangular" array of the integrated structure. It can be seen that the pressure distribution is small and the pressure distribution is uniform, so that the pressure at the steam inlet of the absorber is low, and the pressure difference with the evaporator can be made large with the same number of heat transfer tubes, which is high performance. This tendency is even greater in the "block type" arrangement than in the "comb type" arrangement.

FIGS. 4A and 4B show FIGS. 1A and 1B.
2 and 3 are schematic diagrams of cross sections as seen from the longitudinal direction of the heat transfer tube of the absorber, respectively, which are almost the same as the above. Similar to FIG. 1, the tube group block 10 surrounded by the vapor flow path 3 has the tube group block 10 in contact with the absorbent discharge port or the extraction port 7, and the number of heat transfer tubes is greater than that of other tube group blocks. Therefore, the pressure near the extraction port 7 is reduced. By doing so, the non-condensable gas such as air in the absorber can be efficiently extracted and the heat transfer characteristics are improved.

FIGS. 5A and 5B also show FIGS. 1A and 1B.
2 and 3 are schematic diagrams of cross sections as seen from the longitudinal direction of the heat transfer tube of the absorber, respectively, which are almost the same as the above. As in the case of FIG. 1, the tube group block 2 surrounded by the vapor flow path 3 is provided, and the dispersion plate 11 that simultaneously allows the vapor and the liquid to pass through is installed in the vapor flow path to redistribute the absorbing liquid. As a result, the absorbing liquid is distributed to all the heat transfer tubes, and the vapor can be absorbed efficiently.

FIGS. 6A and 6B show such a dispersion plate 1
It is sectional drawing which respectively shows two examples of No. 1. In FIG. 1 (1), a short cylinder 112 that allows gas to pass through the perforated plate 111 is provided so as to protrude upward, and the liquid accumulated on the perforated plate 111 is dropped from the holes of the perforated plate 111. In FIG. 2B, a short cylinder 113 having a relatively large diameter is provided so as to penetrate the plate 114 and protrude upward, and the liquid accumulated on the plate 114 is contained in the cylinder 113.
It overflows inward and flows down the inner wall of the cylinder 113 in a wet state, and the gas flows in the central portion of the cylinder 113.

FIGS. 7 (1) and 7 (2) are schematic views of two embodiments of the evaporator of the absorption refrigerator according to the present invention, as viewed in the longitudinal direction of the heat transfer tube. Four tube group blocks 2 in which the heat transfer tubes 1 are densely arranged are formed in the evaporator, and each tube group block is surrounded by the vapor flow path 3. From the upper part of the tube group, an evaporation medium 13 such as water is sprayed from the evaporation medium spraying device 12 to the outer surface of the heat transfer tubes and evaporated. The vaporized vapor flows out from the vapor outflow portion 14 to the absorber through the vapor flow path 3.
The evaporation medium which has reached the lower portion of the evaporator without being completely evaporated flows out of the evaporator through the evaporation medium outlet 15.

8 (1) and 8 (2) are shown in FIGS. 7 (1) and 7 (2).
2 and 3 are schematic diagrams of cross-sections as seen from the longitudinal direction of the heat transfer tube of the evaporator, which are almost the same as the above. As in the case of FIG. 7, the dispersion plate 11 having the tube group block 2 surrounded by the vapor flow path 3 and simultaneously allowing the vapor and the liquid to pass through the vapor flow path (similar to (1) or (2) in FIG. 6). Stuff) and redistribute the liquid. As a result, water as an evaporation medium is distributed to all the heat transfer tubes, and heat transfer characteristics are improved.

[0024]

According to the present invention, it is possible to reduce the flow resistance of vapor in the absorber or the evaporator of the absorption refrigerator and to provide a high-performance absorption refrigerator. Further, in the absorber, the pressure distribution in the whole absorber can be made uniform by constructing a block tube group, and the non-condensation can be achieved by artificially reducing the pressure near the extraction port as shown in FIG. The characteristic gas can be efficiently extracted and the absorption heat transfer characteristic in the absorber can be improved. In addition, by installing a dispersion plate for the liquid that does not affect the vapor flow in the tube group of the absorber or evaporator, the absorbing liquid or the evaporating medium liquid is evenly distributed to the heat transfer tubes below the tube group. It is possible to further improve the heat transfer characteristics without generating a wasteful tube such that the liquid is not supplied. INDUSTRIAL APPLICABILITY As described above, the present invention can provide a high-performance absorption refrigerating machine, and can exert a refrigerating capacity higher than that of the prior art with a small device.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view in a longitudinal direction of a heat transfer tube of an absorber of an absorption refrigerator according to an embodiment of the present invention,

FIG. 2 is a schematic view of a cross section of an absorber according to a conventional technique and the present invention used for numerical analysis,

FIG. 3 is a diagram showing a pressure distribution by numerical analysis of the pipe group shown in FIG.

FIG. 4 is a schematic cross-sectional view in the longitudinal direction of the heat transfer tube of the absorber of the absorption refrigerator according to another embodiment of the present invention,

FIG. 5 is a schematic sectional view of an absorber according to still another embodiment of the absorption refrigerator of the present invention,

FIG. 6 is a schematic sectional partial view of a dispersion plate used in the present invention,

FIG. 7 is a schematic cross-sectional view in the longitudinal direction of the heat transfer tube of the evaporator of the absorption refrigerator according to the embodiment of the present invention,

FIG. 8 is a schematic sectional view of an evaporator according to another embodiment of the absorption refrigerator of the present invention,

FIG. 9 is a conceptual diagram of the entire system of an absorption refrigerator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heat transfer tube 2 ... Tube group block 3 ... Steam flow path 4 ... Inflow part of vapor | steam which flows in from an evaporator 5 ... Absorbing liquid spraying device 6 ... Absorbing liquid 7 ... Absorbing liquid discharge port or bleeding port 8 ... Heat transfer pipe arrangement area 9 ... Pressure plotting position 10 ... Tube block block adjacent to the absorbing liquid discharge port or bleeding port 7 ... Dispersing plate for simultaneously passing vapor and liquid 12 ... Evaporating medium spraying device 13 ... Evaporating medium 14 ... Vapor outflow portion 15 ... Evaporating medium Vent

Front Page Continuation (72) Fumio Takahashi 1168 Moriyama-cho, Hitachi City, Ibaraki Pref., Energy Research Laboratory, Hitachi, Ltd.

Claims (11)

[Claims] 1. An absorption refrigerator having an evaporator that evaporates liquid on the surfaces of a plurality of heat transfer tubes to generate steam and an absorber that absorbs steam flowing from the evaporator with an absorbing liquid on the surfaces of the plurality of heat transfer tubes. In the absorption refrigerator, the absorber has a plurality of tube group regions separated by a steam flow path in a cross section viewed from the longitudinal direction of the heat transfer tube. 2. An absorption refrigerator having an evaporator that evaporates liquid on the surfaces of a plurality of heat transfer tubes to generate steam and an absorber that absorbs steam flowing from the evaporator with an absorbing liquid on the surfaces of the plurality of heat transfer tubes. In the case of the absorber, in the cross section viewed from the longitudinal direction of the heat transfer tube, a plurality of tube group areas in which the heat transfer tubes are densely arranged and steam having an interval larger than the maximum value of the interval between the adjacent heat transfer tubes in each tube group area. An absorption refrigerator having a flow path and each of the plurality of tube group regions in which heat transfer tubes are densely arranged is surrounded by the steam flow path. 3. An absorption refrigerator having an evaporator that evaporates liquid on the surfaces of a plurality of heat transfer tubes to generate steam and an absorber that absorbs steam flowing from the evaporator with an absorbing liquid on the surfaces of the plurality of heat transfer tubes. In the case of the absorber, in the cross section viewed from the longitudinal direction of the heat transfer tube, a plurality of tube group areas in which the heat transfer tubes are densely arranged and steam having an interval larger than the maximum value of the interval between the adjacent heat transfer tubes in each tube group area. Each of the plurality of tube group regions having a flow path and densely arranged heat transfer tubes is surrounded by the steam flow path, and in a cross section viewed from the steam inflow surface to the absorber, An absorption refrigerator in which each of the plurality of densely arranged tube group regions is divided by a vapor flow path having an interval larger than a maximum value of an interval between adjacent heat transfer tubes in the region. 4. The number of rows of the heat transfer tubes belonging to one tube group region in a direction perpendicular to the steam inflow direction is 20 or less.
Absorption refrigerator described. 5. An absorption refrigerator having an evaporator that evaporates liquid on the surfaces of a plurality of heat transfer tubes to generate steam and an absorber that absorbs steam flowing from the evaporator with an absorbing liquid on the surfaces of the plurality of heat transfer tubes. In the cross section when the absorber is viewed from the longitudinal direction of the heat transfer tube, a tube group area in which the heat transfer tubes are densely arranged and a steam flow path having an interval larger than the maximum value of the interval between the adjacent heat transfer tubes in each tube group area are provided. Each of the plurality of tube group regions in which the heat transfer tubes are densely arranged are separated by the vapor flow path, and the tube group region closest to the absorbing liquid discharge port or the bleed port in the absorber is another. An absorption refrigerator having a larger number of heat transfer tubes or a narrower heat transfer tube pitch than the tube group region. 6. The absorption refrigerator according to claim 1, wherein a dispersion plate that allows liquid and gas to pass through at the same time is arranged in the tube group region in the absorber or in the vapor flow path. .. 7. An absorption refrigerator having an evaporator that evaporates liquid on the surfaces of a plurality of heat transfer tubes to generate steam and an absorber that absorbs steam flowing from the evaporator with an absorbing liquid on the surfaces of the plurality of heat transfer tubes. In the absorption refrigerator, the evaporator has a plurality of tube group regions separated by a steam flow path in a cross section viewed from the longitudinal direction of the heat transfer tube. 8. An absorption refrigerator having an evaporator that evaporates liquid on the surfaces of a plurality of heat transfer tubes to generate steam and an absorber that absorbs the steam flowing from the evaporator with an absorbing liquid on the surfaces of the plurality of heat transfer tubes. In the evaporator, the vaporizer is a steam with a distance larger than the maximum value of the distance between the plurality of tube group areas in which the heat transfer tubes are densely arranged and the adjacent heat transfer tubes in each tube group area in the cross section viewed from the longitudinal direction of the heat transfer tube. An absorption refrigerator having a flow path and each of the plurality of tube group regions in which heat transfer tubes are densely arranged is surrounded by the steam flow path. 9. An absorption chiller having an evaporator that evaporates liquid on the surfaces of a plurality of heat transfer tubes to generate steam and an absorber that absorbs steam flowing from the evaporator with an absorbing liquid on the surfaces of the plurality of heat transfer tubes. In the evaporator, the vaporizer is a steam with a distance larger than the maximum value of the distance between the plurality of tube group areas in which the heat transfer tubes are densely arranged and the adjacent heat transfer tubes in each tube group area in the cross section viewed from the longitudinal direction of the heat transfer tube. Each of the plurality of tube group regions having a flow path and densely arranged heat transfer tubes is surrounded by the steam flow path, and in a cross section viewed from the steam outflow surface from the evaporator, An absorption refrigerator in which each of the plurality of densely arranged tube group regions is divided by a vapor flow path having an interval larger than a maximum value of an interval between adjacent heat transfer tubes in the region. 10. The absorption refrigerator according to claim 9, wherein the number of rows of the heat transfer tubes belonging to one tube group region is 20 or less in a direction perpendicular to the steam outflow direction. 11. The absorption refrigerator according to claim 7, wherein a dispersion plate that allows liquid and gas to pass through at the same time is arranged in the tube group region in the evaporator or in the vapor flow path. ..