JP4903743B2 - Absorption refrigerator - Google Patents

Description

  The present invention relates to an absorption refrigerator, and particularly suitable for a two-stage absorption refrigerator having two sets of evaporators and absorbers and configured to cool the low-pressure side absorber by the high-pressure side evaporator. Is.

  As a conventional technique, there is a two-stage absorption heat pump apparatus disclosed in Japanese Patent Laid-Open No. 7-139844 (Patent Document 1).

  In Patent Document 1, two sets of evaporators and absorbers are installed, and the low temperature side absorber is cooled by the high temperature side evaporator. Heat transport from the low-temperature side absorber to the high-temperature side evaporator is carried out by using the heat pipe 23 and the liquid refrigerant of the high-temperature side evaporator circulating in the heat transfer tube of the low-temperature side absorber to take away the heat of absorption. An example of flash evaporation in a side evaporator is shown. Moreover, the structure of the piping which connects the suction piping of the refrigerant | coolant pump which sprays the liquid refrigerant of the low temperature side evaporator, and the lower part of a high temperature side evaporator is shown.

  As another conventional technique, there is an absorption refrigerator disclosed in Japanese Patent Laid-Open No. 2000-227262 (Patent Document 2).

  In this patent document 2, it has two sets of evaporators and absorbers, and is composed of the same can body next to each other in the order of a low temperature side evaporator, a low temperature side absorber, a high temperature side evaporator, and a high temperature side absorber. The side evaporator and the low temperature side absorber are adjacent to each other via a bellows-shaped heat transfer surface, and a liquid refrigerant spraying means for spraying liquid refrigerant in the vicinity of the heat transfer surface of the high temperature side evaporator is provided with a low temperature side absorber. Solution spraying means for spraying the solution is disposed in the vicinity of the heat transfer surface, and the liquid refrigerant spraying means is positioned above the solution spraying means.

JP-A-7-139844 JP 2000-227262 A

  In Patent Document 1, heat transfer from the low-temperature side absorber to the high-temperature side evaporator is performed by heat transport using a heat pipe or sensible heat of a liquid refrigerant, so that the heat exchange temperature difference becomes large. There was a problem that the difference in pumping temperature of the minute cycle was reduced.

  On the other hand, in Patent Document 2, the high temperature side evaporator and the low temperature side absorber are adjacent to each other through the heat transfer surface, and the absorption heat of the low temperature side absorber is directly transmitted to the high temperature side evaporator. Compared with Patent Document 1, the heat exchange temperature difference can be reduced, and the pumping temperature difference of the cycle can be increased accordingly.

  However, in Patent Document 2, no consideration is given to the flow resistance of steam from the high temperature side evaporator to the high temperature side absorber. That is, the steam generated from the surface of the high-temperature side evaporator tends to rise. However, since there is a spraying device, the upward steam escape is poor and the flow resistance increases. If this resistance is large, the absorption efficiency of the vapor in the high-temperature side absorber will deteriorate, the temperature difference between the high-temperature side absorber and the high-temperature side evaporator will increase, and the pumping temperature difference in the cycle will decrease accordingly. there were.

  Patent Document 2 does not specifically describe a configuration in which a plurality of heat transfer tubes arranged horizontally in a low-temperature evaporator and a high-temperature absorber are expanded and fixed to a tube plate. When expanding and fixing a plurality of heat transfer tubes to the tube plate, it is important to prevent leakage at the expanded portion of the heat transfer tubes.

  In addition, in patent document 2, since it is the complicated structure which has arrange | positioned the low temperature absorber which consists of a bellows-shaped heat-transfer surface, and a high temperature evaporator, there also exists a subject that manufacture becomes troublesome.

  An object of the present invention is to obtain an absorption refrigerator that can increase the pumping temperature difference and prevent leakage of the expanded portion of the heat transfer tube.

In order to achieve the above object, the present invention provides a low temperature evaporator, a low temperature absorber, a high temperature evaporator, a high temperature absorber, a regenerator, a condenser, a solution heat exchanger, a refrigerant pump, and a solution circulation pump as a solution pipe and In an absorption refrigeration machine connected with a refrigerant pipe to form a solution / refrigerant circulation circuit and cooling the absorption heat of the low temperature absorber with the latent heat of evaporation of the high temperature evaporator, the low temperature evaporator, the low temperature absorber, The low temperature where the high temperature evaporator and the high temperature absorber are constituted by one can, and the plurality of heat transfer tubes are vertically arranged between the low temperature evaporator and the high temperature absorber where the plurality of heat transfer tubes are horizontally arranged. the absorber and the high temperature evaporator disposed, said cold evaporator is communicated to said inner side of a plurality of heat transfer tubes said vertically arranged outside the plurality of heat transfer tubes said vertically arranged as the cold absorber Connected to the high-temperature absorber as a high-temperature evaporator The refrigerant liquid is supplied into each heat transfer tube from the upper part of the plurality of vertical heat transfer tubes, and the low-temperature evaporator, the low-temperature absorber, and the high-temperature evaporation are formed using two first tube plates. And both ends of the plurality of heat transfer tubes of the low-temperature evaporator and both ends of the plurality of heat transfer tubes of the high-temperature absorber are formed on the two first tube plates. It is in expanding and fixing.

A more preferable specific configuration example of the present invention is as follows.
(1) The thickness of the first tube sheet is made thicker than the thickness of the outer wall constituting the can body.
(2) Both ends of the plurality of heat transfer tubes forming the high temperature evaporator and the low temperature absorber are expanded and fixed to a second tube plate, and both ends of the second tube plate are connected to the first tube plate. It was welded and fixed to the inner surface.
(3) The plate thickness of the second tube plate is made thicker than the plate thickness of the outer wall that constitutes the can body so as to be the same thickness as the first tube plate.

  According to the present invention, the heat exchange temperature difference between the low temperature absorber and the high temperature evaporator can be reduced, the steam flow resistance from the high temperature evaporator to the high temperature absorber can be reduced, and the pumping temperature difference can be increased. In addition, deformation of the can body can be prevented to improve the sealing performance at the tube expansion portion, and leakage at the tube expansion portion can be prevented.

  Hereinafter, an absorption refrigerator according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5.

  FIG. 1 is a cycle system diagram of an absorption refrigerator according to the present invention. The absorption refrigerator includes a regenerator 1, a condenser 4, a high temperature absorber 6, a high temperature evaporator 14, a low temperature absorber 11, a low temperature evaporator 17, a solution heat exchanger 25 and 26, a solution pump 22, 23, 24, Refrigerant pumps 20 and 21 are provided. Here, the refrigerant is water, and the solution is an aqueous lithium bromide solution that absorbs evaporated water.

  A heat transfer tube 3 is provided in the regenerator 1, and a solution spraying device 2 is disposed above the heat transfer tube 3. A heat transfer tube 5 is provided inside the condenser 4. The regenerator 1 and the condenser 4 are connected via a steam passage 29. The bottom of the regenerator 1 is connected to the solution spraying device 7 provided on the upper portion of the high-temperature absorber 6 through a pipe via a solution pump 24 and a solution heat exchanger 26.

  The low temperature evaporator 17, the low temperature absorber 11, the high temperature evaporator 14, and the high temperature absorber 6 are configured as one can. Further, the high temperature evaporator 14 and the low temperature absorber 11 are constituted by the integrated evaporation absorber 10 and are disposed between the low temperature evaporator 17 and the high temperature absorber 6. An eliminator 9 is provided between the high-temperature absorber 6 and the integrated evaporation absorber 10, and an eliminator 13 is provided between the low-temperature evaporator 17 and the integrated evaporation absorber 10. The integrated evaporator 10 is partitioned by a partition wall 30 into a high temperature evaporator side space 14a and a low temperature absorber side space 11a. The partition wall 30 has second tube plates 52 and 53 extending horizontally at the upper and lower portions thereof.

  A plurality of heat transfer tubes 8 arranged substantially horizontally are arranged inside the high temperature absorber 6, and a solution tank 33 is provided below the high temperature absorber 6. The bottom of the solution tank 33 is connected to the solution spraying device 12 provided on the upper part of the low-temperature absorber 5 through the solution pump 23, the solution heat exchanger 25, and piping.

  The high-temperature evaporator 14 is configured in a plurality of heat transfer tubes 16 arranged substantially vertically. The upper part of the heat transfer tube 16 is opened to the refrigerant spraying device 15 and connected to the high temperature absorber 6 via the high temperature evaporator side space 14 a and the eliminator 9. A lower portion of the heat transfer tube 16 is opened to the high temperature evaporator side space 14 a and is connected to the high temperature absorber 6 through the eliminator 9. A refrigerant tank 34 is provided below the high-temperature evaporator 14. The refrigerant tank 34 is connected to the bottom of the condenser 4 through the throttle 28 and piping. The bottom of the refrigerant tank 34 is connected to the bottom of the low-temperature evaporator 17 through the communication pipe 27, and is connected to the refrigerant distribution device 15 provided on the top of the high-temperature evaporator 14 through the refrigerant pump 21 and piping. ing.

  The low-temperature absorber 11 is configured outside the heat transfer tube 16. In the upper part of the low-temperature absorber 11, there is provided a solution spraying device 12 that penetrates the heat transfer tube 16 and supplies a solution from around the heat transfer tube 16 to the outer surface of the heat transfer tube 16. A solution tank 35 is provided below the low-temperature absorber 11. The bottom of the solution tank 35 is connected to the solution spraying device 2 provided at the top of the high-temperature regenerator 1 via the solution pump 22, the solution heat exchangers 25 and 26, and piping.

  A plurality of horizontally arranged heat transfer tubes 19 are provided inside the low-temperature evaporator 17, and a refrigerant spraying device 18 is arranged at the top, and is connected to the low-temperature absorber 11 via the eliminator 13. . A refrigerant tank 36 is provided below the low-temperature evaporator 17. As described above, the bottom of the refrigerant tank 36 is connected to the high-temperature evaporator 14 via the communication pipe 27, and is connected to the refrigerant spraying device 18 provided on the top of the low-temperature evaporator 17 via the refrigerant pump 20 and the pipe. It is connected.

  The operation of the absorption refrigerator configured as described above is as follows.

  The solution sprayed from the solution spraying device 2 in the regenerator 1 exchanges heat with the heating medium flowing in the pipe on the heat transfer pipe 3 to generate refrigerant vapor. The concentrated solution generated by generating the refrigerant vapor is sent to the solution heat exchanger 26 by the solution pump 24, cooled by exchanging heat with the solution from the low temperature absorber 11, and supplied to the solution spraying device 7 of the high temperature absorber 6. Sent.

  The solution sprayed from the solution spraying device 7 in the high-temperature absorber 6 absorbs the refrigerant vapor from the high-temperature evaporator 14 on the heat transfer tube 8, and the absorption heat generated by the refrigerant absorption is caused by the cooling water flowing in the heat transfer tube 8. To be cooled. The solution whose concentration is reduced by absorbing the refrigerant vapor is temporarily stored in the solution tank 33 below the high-temperature absorber 6, and sent to the solution heat exchanger 25 by the solution pump 23. The solution heat exchanger 25 is cooled by exchanging heat with the solution from the low-temperature absorber 11 and sent to the solution spraying device 12 of the low-temperature absorber 11.

  The solution supplied from the solution spraying device 12 to the outer surface of the heat transfer tube 16 in the low-temperature absorber 11 flows down to the outer surface of the vertical heat transfer tube 16 and absorbs the refrigerant vapor from the low-temperature evaporator 17 while flowing down. The absorbed heat generated by the refrigerant absorption is cooled by the refrigerant flowing down the inner surface of the heat transfer tube 16. The solution whose concentration is further reduced by absorbing the refrigerant vapor is temporarily stored in the solution tank 35 below the low-temperature absorber 11 and sent to the solution heat exchanger 25 by the solution pump 22. The solution whose temperature has been increased by exchanging heat with the solution from the high-temperature absorber 6 in the solution heat exchanger 25 is further heated by exchanging heat with the solution from the regenerator 1 in the solution heat exchanger 26, and then the regenerator 1. To the solution spraying device 2.

  On the other hand, the refrigerant vapor generated in the regenerator 1 is sent to the condenser 4 through the vapor passage 29 and is condensed and liquefied on the surface of the heat transfer tube 5. The condensation heat at this time is cooled by the cooling water flowing in the heat transfer tube 5. The condensed and liquefied refrigerant passes through the throttle 28 from the bottom of the condenser 4 and is temporarily stored in the refrigerant tank 34 below the high-temperature evaporator 14.

  The liquid refrigerant stored in the refrigerant tank 34 is sent to the low-temperature evaporator 17 through the communication pipe 27 and also sent to the refrigerant spraying device 15 above the high-temperature evaporator 14 by the refrigerant pump 21. The liquid refrigerant sent to the refrigerant spraying device 15 flows down as a liquid film from the upper opening of the heat transfer tube 16 along the inner wall of the tube, and evaporates by receiving heat absorbed from the solution flowing down the tube. The evaporated refrigerant vapor passes through the inside of the refrigerant liquid film flowing down along the inner wall of the heat transfer tube 16 and flows out from the upper and lower openings of the heat transfer tube 16 to the high-temperature evaporator side space 14a. It is sent to the high temperature absorber 3 through. The liquid refrigerant that could not be evaporated on the inner surface of the heat transfer tube 16 is stored in the refrigerant tank 34 below the high-temperature evaporator 14.

  As described above, since the refrigerant liquid is supplied into the heat transfer tube 16 from the top of the plurality of heat transfer tubes 16 constituting the integrated evaporation absorber 10, the two-phase flow in the heat transfer tube 16 has a large pressure loss. Instead of a void flow or a slag flow, a falling liquid film of the refrigerant is formed around the cross section in the pipe, and an annular flow in which the refrigerant vapor flows inside thereof. Accordingly, the pressure loss is reduced, the pressure distribution in the flow direction and the change in the evaporation temperature are reduced, and the entire heat transfer tube works effectively, whereby the heat transfer area can be reduced.

  The liquid refrigerant sent from the high-temperature evaporator 14 to the low-temperature evaporator 17 through the communication pipe 27 is sent to the refrigerant spraying device 18 above the low-temperature evaporator 17 by the refrigerant pump 20. The liquid refrigerant of the refrigerant spraying device 18 is sprayed on the heat transfer tube 19, takes heat from the cold water flowing in the heat transfer tube 19, evaporates, and is sent to the low-temperature absorber 11 through the eliminator 13. The liquid refrigerant that could not be evaporated on the heat transfer tube 19 is stored in the refrigerant tank 36 below the low-temperature evaporator 17.

  As described above, in the absorption refrigerator of the present embodiment, the refrigerant vapor is absorbed into the solution by the outer surfaces of the plurality of heat transfer tubes 16 installed vertically, and the absorbed heat flows down the inner surface of the heat transfer tubes 16. Since direct cooling is performed by the latent heat of vaporization of the refrigerant, the heat exchange temperature difference between the low temperature absorber 11 and the high temperature evaporator 14 can be reduced. At the same time, the pressure of the high temperature evaporator 14 is higher than the pressure of the low temperature evaporator 17, and the bottom of the high temperature evaporator 14 and the low temperature evaporator 17 communicate with each other via the communication pipe 27. The liquid refrigerant stored in the refrigerant tank 35 is operated at a level lower than the liquid refrigerant stored in the refrigerant tank 36 below the low-temperature evaporator 17.

  Thereby, the height of the partition between the refrigerant tank 34 and the solution tank 33 can be made lower than the height of the partition between the refrigerant tank 36 and the solution tank 35, so that the high temperature evaporator 14 and the high temperature absorber 6 The flow passage area of the vapor passage (eliminator 9) can be increased, and the flow resistance of the refrigerant vapor can be reduced. This resistance reduction increases the absorption efficiency of the refrigerant vapor in the high-temperature absorber 6, can increase the temperature drop between the high-temperature absorber 6 and the high-temperature evaporator 14, and from the low-temperature evaporator 17 to the high-temperature absorber 6. The difference in pumping temperature can be increased.

  Further, since the refrigerant vapor is guided from both the upper opening and the lower opening of the heat transfer tube 16 of the high-temperature evaporator 14 and sent to the high-temperature absorber 6, the flow resistance of the refrigerant vapor can be reduced. Thereby, the temperature drop between the high temperature absorber 6 and the high temperature evaporator 14 can be increased, and the pumping temperature difference from the low temperature evaporator 17 to the high temperature absorber 6 can be increased. On the contrary, if the pumping temperature difference is equal, the heat transfer area of each evaporator and absorber can be reduced, and a small and low-cost absorption refrigerator can be provided.

  Next, the configuration of the low-temperature evaporator 17, the low-temperature absorber 11 and the high-temperature evaporator 14 and the integrated evaporator 10 and the high-temperature absorber 6 will be described with reference to FIGS.

  FIG. 2 is a side view of the can 60 constituting the low-temperature evaporator 17, the low-temperature absorber 11 and the high-temperature evaporator 14, and the integral-type evaporation absorber 10 and the high-temperature absorber 6 shown in FIG. 1.

  The can outer wall 61 is formed in a square cylindrical shape by welding a plurality of steel plate members, and the front and rear surfaces are opened. The first tube plates 50, 51 are steel plate members for expanding and fixing the plurality of heat transfer tubes 19, 8 arranged horizontally in the low temperature evaporator 17 and the high temperature absorber 6. Is welded to the outer wall 61 of the can. The first tube sheets 50 and 51 are formed of a single member thicker than the can outer wall 61. The headers 54 and 55 are for distributing cooling water flowing through the heat transfer tubes 8 of the high-temperature absorber 6, and are welded to the outside of the first tube plates 50 and 51 so as to cover both end openings of the heat transfer tubes 8. Has been.

  3 is a cross-sectional view taken along the line AA in FIG. The second tube plates 52 and 53 are steel plate members for expanding and fixing the plurality of vertically arranged heat transfer tubes 16 constituting the integrated evaporation absorber 10, and are disposed so as to face each other vertically. It extends. The second tube sheets 52 and 53 constitute a part of the partition wall 30 as described above.

  4 is a cross-sectional view taken along line BB in FIG. The headers 56 and 57 are for distributing cold water flowing in the heat transfer tube 19 of the low-temperature evaporator 17, and are welded to the outside of the first tube plates 50 and 51 so as to cover the openings at both ends of the heat transfer tube 8. Has been. The second tube plates 52 and 53 are formed by a single member thicker than the outer wall 61 of the can, and are formed to have substantially the same thickness as that of the first tube plates 50 and 51.

  The low-temperature evaporator 17, the integrated evaporator 10, and the high-temperature absorber 6 are formed of a single can body 60 as shown in FIGS. 3 and 4. The integrated evaporator 10 is disposed between the low temperature evaporator 17 and the high temperature absorber 6, and the first shown in FIG. 5 is disposed at both ends of the heat transfer tube 19 of the low temperature evaporator 17 and the heat transfer tube 8 of the high temperature absorber 6. Tube plates 50 and 51 are arranged, and the outer periphery between the first tube plates 50 and 51 is constituted by a can outer wall 61.

  As described above, the first tube plates 50 and 51 for expanding and fixing the heat transfer tube 19 of the low-temperature evaporator 17 and the heat transfer tube 8 of the high-temperature absorber 6 are integrated and absorbed as shown in FIGS. Since the steel plate member is formed across the vessel 10, the number of parts and the welding location can be minimized. As a result, deformation of the can body due to welding of the first tube plates 50 and 51 can be prevented, and the heat transfer tubes 19 and 8 can be smoothly inserted into the first tube plates 50 and 51. Can improve the sealing performance and prevent leakage at the expanded portion.

  Further, both ends of the heat transfer tube 16 of the integrated evaporator 10 are expanded and fixed to the second tube plates 52 and 53, and both ends in the longitudinal direction of the second tube plates 52 and 53 are connected to the first tube. It is fixed to the plates 50 and 51 by welding. Therefore, when the second tube plates 52 and 53 of the steel plate member thicker than the outer wall 61 are fixed by welding, the first tube plate 50 of the steel plate member thicker than the outer wall 61 is fixed in the same manner as the second tube plates 52 and 53. 51, both ends of the second tube sheets 52 and 53 can be fixed by welding. Thereby, the deformation | transformation by welding of the 2nd tube plates 52 and 53 can be prevented, and since the insertion of the heat exchanger tube 16 to the 2nd tube plates 52 and 53 can be performed smoothly, the sealing performance in a pipe expansion part is possible. It is possible to improve and prevent leakage at the expanded portion.

  In addition, the heat transfer tubes 19 and 8 are expanded and fixed to the first tube plate 50, and a part of the other outer wall 61 of the first tube plate 50, the partition wall 30 including the second tube plates 52 and 53, etc. The can 60 is formed by fixing one side by welding and fixing the other side to the first tube plate 51 by expanding and fixing the first side.

It is a figure which shows the cycle flow of the absorption refrigerator which concerns on one Example of this invention. It is a side view of the can of the absorption refrigeration machine of FIG. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is a front view of the 1st tube sheet of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Regenerator, 2 ... Solution spraying device, 3 ... Heat transfer tube, 4 ... Condenser, 5 ... Heat transfer tube, 6 ... High temperature absorber, 7 ... Solution spraying device, 8 ... Heat transfer tube, 9 ... Eliminator, 10 ... One Body evaporative absorber, 11 ... low temperature absorber, 12 ... solution sprayer, 13 ... eliminator, 14 ... high temperature evaporator, 15 ... refrigerant spray device, 16 ... heat transfer tube, 17 ... low temperature evaporator, 18 ... refrigerant spray device, DESCRIPTION OF SYMBOLS 19 ... Heat-transfer tube, 20, 21 ... Refrigerant pump, 22, 23, 24 ... Solution pump, 25, 26 ... Solution heat exchanger, 27 ... Communication pipe, 28 ... Restriction, 29 ... Steam passage, 30 ... Septum, 33 ... Solution tank, 34 ... refrigerant tank, 35 ... solution tank, 36 ... refrigerant tank, 50, 51 ... first tube plate, 52, 53 ... second tube plate, 60 ... can body, 61 ... can outer wall.

Claims (4)

Low temperature evaporator, low temperature absorber, high temperature evaporator, high temperature absorber, regenerator, condenser, solution heat exchanger, refrigerant pump and solution circulation pump are connected by solution piping and refrigerant piping to form a solution / refrigerant circulation circuit And
In the absorption refrigerator that cools the absorption heat of the low-temperature absorber with the latent heat of evaporation of the high-temperature evaporator,
The low-temperature evaporator, the low-temperature absorber, the high-temperature evaporator and the high-temperature absorber are composed of one can body,
Between the low-temperature evaporator and the high-temperature absorber in which a plurality of heat transfer tubes are arranged horizontally, the low-temperature absorber and the high-temperature evaporator in which a plurality of heat transfer tubes are arranged vertically,
The outside of the plurality of vertically arranged heat transfer tubes communicates with the low temperature evaporator as the low temperature absorber,
The inner side of the plurality of heat transfer tubes said vertically arranged to communicate with the said high temperature absorber as the hot evaporator,
The refrigerant liquid is configured to be supplied into each heat transfer tube from the upper part of the plurality of vertical heat transfer tubes,
Forming both sides of the can body spanning the low temperature evaporator, the low temperature absorber, the high temperature evaporator and the high temperature absorber using two first tube sheets,
An absorption refrigerator, wherein both ends of the plurality of heat transfer tubes of the low-temperature evaporator and both ends of the plurality of heat transfer tubes of the high-temperature absorber are expanded and fixed to the two first tube plates.   2. The absorption refrigerator according to claim 1, wherein a thickness of the first tube sheet is made thicker than a thickness of an outer wall constituting the can body.   In Claim 2, the both ends of these heat exchanger tubes which form the high temperature evaporator and the low temperature absorber inside and outside are expanded and fixed to a second tube sheet, and both ends of the second tube sheet are fixed to the first tube sheet. Absorption type refrigerator characterized by being welded and fixed to the inner surface of the tube sheet. 4. The absorption refrigerator according to claim 3, wherein the thickness of the second tube plate is made thicker than that of the outer wall constituting the can body to be the same thickness as the first tube plate. .

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