JP2007085570A - Absorber and absorption refrigerating machine comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve high performance and miniaturization of an absorber by reducing a thickness of a liquid film and securing a flow rate while preventing rupture of the liquid film. <P>SOLUTION: This absorber 5 for guiding absorbent solution 61 and refrigerant vapor 62 into an absorbing tube 51 to allow the refrigerant vapor 62 to be absorbed by the absorbent solution 61, and radiating absorption heat to the outside of the absorbing tube, comprises a solution introducing portion 53 for introducing the absorbent solution 61 to the absorbing tube 51, and a refrigerant vapor introducing tube 55 for introducing the refrigerant vapor 62 to the absorbing tube 51. This absorber 5 is provided with a solution contraction portion 56 formed in such manner that a slight clearance is formed between an outer face of the refrigerant vapor introducing tube 55 and an inner face of an inlet portion of the absorbing tube 51, an inlet side of the solution contraction portion 56 is communicated in the solution introducing portion 53, and the absorbent solution 61A is circularly jetted along an inner wall of the absorbing tube 51 from the solution contraction portion 56 by pressure of the absorbent solution 61. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an absorber and an absorption refrigerator equipped with the absorber, and is particularly suitable for an absorption refrigerator that performs cooling using fuel or exhaust heat and an absorber used therefor.

  As an absorber used for a conventional absorption refrigerator, there is one shown in FIG. 5 of JP-A-4-116352 (Patent Document 1). The description relating to FIG. 5 of Patent Document 1 discloses as follows. The air-cooled absorber includes an upper header and a lower header, a plurality of heat transfer tubes (absorption tubes) joined to the upper header, and a plurality of air-cooling fins fitted to the outside of the heat transfer tubes. Fine fins are provided inside the heat transfer tube to promote internal heat and mass transfer of the absorbent (absorbent solution). In the upper header, there are arranged a liquid spraying device for flowing down the dense absorbent in the heat transfer tube and a solution duct for distributing the absorbent to the heat transfer tube group. Refrigerant vapor generated in the evaporator is guided into the heat transfer tube from the upper header, and is absorbed by the concentrated absorbent that can flow down inside the heat transfer tube by the solution duct and the liquid spraying device. The absorbed heat at that time is radiated to the cooling air through the heat transfer tubes and the air cooling fins.

JP-A-4-116352

  In the absorber of the conventional patent document 1, since the absorption liquid (falling liquid film) which flows down by the gravity inside the heat exchanger tube is used, when trying to make the falling liquid film thinner in order to improve performance, Problems such as a decrease in the flow rate of the liquid film and a tendency to break the liquid film (dry patch (dry surface)) occur. For this reason, when it was going to ensure the required solution flow volume, the flow-path width | variety will spread and the subject that an absorber will become large sized occurred. Further, Patent Document 1 describes that a fine fin is provided inside the heat transfer tube to promote internal heat and mass transfer of the absorption liquid. However, by heat transfer enhancement of only the fine fin on the heat transfer surface. There is a limit to downsizing.

  An object of the present invention is to achieve high performance and downsizing of an absorber by realizing thin liquid film and securing a flow rate while preventing breakage of the liquid film.

  In order to achieve the above-mentioned object, the present invention is directed to an absorber that guides an absorbent solution and refrigerant vapor into an absorption tube, absorbs the refrigerant vapor into the absorbent solution, and dissipates the heat of absorption outside the absorption tube. A solution introduction part for guiding the absorbent solution to the absorption pipe, and a refrigerant vapor introduction pipe for guiding the refrigerant vapor to the absorption pipe, and an outer surface of the refrigerant vapor introduction pipe and the absorption pipe The inner surface of the inlet portion is formed so as to have a slight gap to form a solution contraction portion, and the inlet side of the solution contraction portion is communicated with the inside of the solution introduction portion, and the solution is adjusted by the pressure of the absorbent solution. The absorbent solution is configured to be ejected in an annular shape from the contracted portion along the inner wall of the absorption tube.

A more preferable specific configuration example of the present invention is as follows.
(1) A spiral groove is formed on the inner surface of the absorption tube.
(2) A spiral groove is formed on the inner surface of the refrigerant vapor introducing pipe.
(3) A plurality of enlarged fins are provided on the outer surface of the absorption tube.
(4) An absorption refrigerator having the above-described absorber.

  According to the present invention, in the absorber that guides the absorbent solution and the refrigerant vapor into the absorption pipe and absorbs the refrigerant vapor into the absorbent solution and dissipates the heat of absorption outside the absorption pipe, the absorbent solution is A solution introduction section for introducing the refrigerant vapor to the absorption pipe; and a refrigerant vapor introduction pipe for introducing the refrigerant vapor to the absorption pipe; and a slight gap between the outer surface of the refrigerant vapor introduction pipe and the inner surface of the inlet section of the absorption pipe. The solution contraction part is formed so as to have an inlet side of the solution contraction part connected to the solution introduction part, and the inner wall of the absorption tube is formed from the solution contraction part by the pressure of the absorbent solution. Since the absorbent solution is configured to be ejected in a ring shape along the line, a large flow rate solution can be flowed as an extremely thin liquid film. In addition, since the absorbent solution has a large kinetic energy at the solution ejection portion, the static pressure is reduced and the refrigerant vapor can be sucked effectively, and the flow of the absorbent solution and the refrigerant vapor is at the downstream portion. A part of the excess kinetic energy at the solution jetting part is recovered as an increase in static pressure by being familiar and stress balanced. Furthermore, since the absorbent solution and the refrigerant vapor flow on the inner surface of the absorption tube as a two-phase flow in the tube, the liquid film breaks (dry patch (dry surface)), which has been a problem with conventional gravity falling liquid film type absorption tubes. Can be suppressed. With these, in the present invention, it is possible to greatly increase the flow rate compared to the case of relying only on conventional gravity, and it is possible to achieve both a thin liquid film and an increase in the flow rate while preventing breakage of the liquid film, It is possible to improve the performance and size of the absorber.

  Further, according to the preferred configuration example (1), since the helical groove is formed on the inner surface of the absorption tube, the absorbent solution injected in an annular shape into the absorption tube can be swirled, and the centrifugal The liquid film can be made thinner by force. Furthermore, since the grooved surface of the absorption tube also functions as an expansion fin, the heat transfer area increases with respect to the volume of the absorbent solution passing therethrough, and the liquid film thickness is substantially reduced. For this reason, the big heat-transfer promotion effect is acquired.

  Moreover, according to the preferable configuration example (2), since the spiral groove is formed on the inner surface of the refrigerant vapor introducing pipe, the refrigerant vapor also flows into the absorber as a swirling flow. For this reason, a swirl flow in the absorber can be generated more effectively, and further absorption promotion can be achieved.

  Moreover, according to the preferable configuration example (3), since the expansion fin is provided on the outer surface of the absorption tube, it can be directly cooled by the surrounding air. An air-cooled absorber can be realized, and a further reduction in size and size can be achieved.

  Moreover, according to the said preferable structural example (4), since the absorber mentioned above is used for an absorption refrigerator, a very high performance and small absorption refrigerator can be implement | achieved.

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. The same reference numerals in the drawings of the respective embodiments indicate the same or equivalent.
(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.

  First, the entire absorption refrigerator according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cycle configuration diagram of an absorption refrigerator according to a first embodiment of the present invention.

  In FIG. 1, 1 is a high temperature regenerator, 2 is a low temperature regenerator, 3 is a condenser, 4 is an evaporator, 5 is an absorber, 7 is a high temperature heat exchanger, 9 is a solution pump, 10 is a refrigerant pump, 11 is Cold water, 12 is a hot water heat exchanger, 13 is hot water, 17 is a liquid heat exchanger, 19 is a solution pump, and 21 is a pressure reducing means for refrigerant in the high temperature regenerator 1 that has heated the low temperature regenerator 2.

  The cooling cycle of the absorption refrigerator according to this embodiment will be described.

  During the cooling operation, the high temperature regenerator 1 heats the absorbent solution in the chamber with an external heat source to generate refrigerant vapor and condense. The generated refrigerant vapor is introduced into the heat exchanger in the low-temperature regenerator 2 through the vapor duct, and the absorbent solution in the low-temperature regenerator 2 is heated to condense and liquefy itself through the pipe and the decompression means 21. And introduced into the condenser 3.

  The high temperature heat exchanger 7 exchanges heat between the concentrated solution generated in the high temperature regenerator 1 and the dilute solution flowing into the high temperature regenerator 1. The low temperature regenerator 2 uses the latent heat of condensation of the refrigerant vapor generated in the high temperature regenerator 1 as a heating source to heat the absorbent solution in the container to generate refrigerant vapor to generate a concentrated solution. The condenser 3 guides the refrigerant vapor generated in the low-temperature regenerator 2 into the apparatus and cools it with the cooling water 39 passing through the heat transfer tube group to condense and liquefy the refrigerant vapor generated in the high-temperature regenerator 1. The refrigerant condensed and liquefied in the heat exchanger of the condenser 2 is introduced into the condenser 3 through the decompression means 21 and further cooled by the cooling water 39 passing through the heat transfer tube group.

  The liquid refrigerant generated in the condenser 3 is introduced into the evaporator 4 via a conduit and a pressure reducing means 24 such as a U-shaped liquid seal or the like due to a head difference in position or liquid transporting means, and on the heat transfer tube group in the evaporator 4. The heat is exchanged with the cold water 11 which is sprayed by the refrigerant pump 10 and flows in the heat transfer tube, and is evaporated. The cold water 11 is cooled by the latent heat of vaporization of the refrigerant at this time, and exhibits cooling capacity.

  The refrigerant vapor evaporated by the evaporator 4 is guided to the absorber 5. In the absorber 5, a concentrated solution mixed with the thick absorbent solution generated in the regeneration chamber 15, the high temperature regenerator 1 and the low temperature regenerator 2 is supplied into the absorber 5 by the solution pump 19, and the concentrated solution is absorbed in the absorber. 5 is cooled with air or cooling water passing through the outside, and is diluted by absorbing refrigerant vapor from the evaporator 4 to form a diluted solution.

  The dilute solution generated in the absorber 5 is sent to the liquid heat exchanger 17 by the solution pump 9 and preheated, partly to the low temperature regenerator 2 and the rest to the high temperature regenerator via the high temperature heat exchanger 7. Transported to vessel 1 The concentrated solution generated in the high temperature regenerator 1 is mixed with the concentrated solution generated in the low temperature regenerator 2 via the high temperature heat exchanger 7 to become a concentrated solution, and the liquid heat exchanger 17 is moved by the solution pump 19. Via, it is supplied to the absorber 5. The liquid heat exchanger 17 exchanges heat between the concentrated solution to be sent to the absorber 5 and the dilute solution to be sent to the low temperature regenerator 2 and the high temperature regenerator 1 to reduce the heat release amount of the solution sensible heat of the absorber 5 and to regenerate at low temperature. The dilute solution sent to the regenerator 2 and the high temperature regenerator 1 is preheated to increase the amount of refrigerant vapor generated in the low temperature regenerator 2 and the high temperature regenerator 1.

  Next, the heating cycle will be described. At the time of heating, the high-temperature refrigerant vapor generated in the high-temperature regenerator 1 is guided to the hot water heat exchanger 12 and condensed to heat the hot water 13 flowing in the heat transfer tube group, thereby obtaining the heating capacity. The liquid refrigerant condensed and liquefied by the hot water heat exchanger 12 is returned into the high temperature regenerator 1 via the U-shaped liquid seal. The heating cycle is configured as described above.

  The concentrated solution and concentrated solution produced by the high temperature regenerator 1 and the low temperature regenerator 2 are absorbent solutions using, for example, lithium bromide as an absorbent and water as a refrigerant.

  Next, the absorber 5 of this embodiment will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the introduction portion of the absorbent solution and the refrigerant vapor in the absorber according to the first embodiment of the present invention, and FIG.

  The absorber 5 is supplied from an absorption pipe 51 for absorbing the refrigerant vapor 62 into the absorbent solution 61, a cooling pipe (not shown) provided outside the absorption pipe 51, and the regenerators 1 and 2. A solution introduction part 53 for introducing the absorbent solution 61, which is a concentrated solution, to the absorption pipe 51, an inlet pipe 54 of the solution introduction part 53, and a refrigerant vapor introduction pipe 55 for introducing the refrigerant vapor 62 to the absorption pipe 51 are provided. I have.

  The absorption pipe 51 is formed of a metal cylindrical pipe, and an inlet part 51 a thereof is inserted into the solution introduction part 53. The refrigerant vapor introduction pipe 55 is formed of a metal cylindrical pipe, and a central portion 55a extends from the opposite side of the absorption pipe 51 through the solution introduction section 53 to the absorption pipe 51 side, and an end 55b thereof is the absorption pipe. 51 is inserted into the inlet 51a. Here, the outer surface of the outflow side end portion 55b of the refrigerant vapor introducing pipe 55 and the inner surface of the inlet section 51a of the absorption pipe 51 are formed to have a slight gap to form the solution contraction section 56. The solution contraction portion 56 has a small annular cross-sectional area. The inlet side of the solution contraction part 56 communicates with the solution introduction part 53, and the outlet side of the solution contraction part 56 communicates with the absorption pipe 51. The inlet portion 51 a of the absorption tube 51 is supported on one side surface of the solution introduction portion 53, and the refrigerant vapor introduction tube 55 is supported on the other side surface of the solution introduction portion 53.

  The high-pressure absorbent solution 61 from the regenerators 1 and 2 is supplied into the solution introduction part 53 through the inlet pipe 54 and has a small cross-sectional area constituted by the inner surface of the absorption pipe 51 and the outer surface of the refrigerant vapor introduction pipe 55. As shown in FIG. 2 and FIG. 3, it passes through the solution constricted portion 56 and is ejected along the inner wall of the absorption pipe 51 to form an annular thin liquid film flow 61A. Usually, the outside of the absorption pipe 51 is cooled by cooling water, and the absorption heat 7 is released in the absorption pipe 51. Since the refrigerant vapor 62 is absorbed by the thin liquid film flow 61 </ b> A, the refrigerant vapor 62 is sucked into the absorption pipe 51 from the refrigerant vapor introduction pipe 55. According to this embodiment, the absorbent solution 61 with a large flow rate can be flowed as an extremely thin thin film flow 61A. For this reason, compared with the case where it relies only on the conventional gravity, a flow volume increases significantly, and it becomes possible to make a thin liquid film and an increase in flow volume compatible.

  Since the absorbent solution 61A has a large kinetic energy at the ejection portion from the solution constricted portion 56, the static pressure is reduced, and the refrigerant vapor 62A can be effectively sucked as shown by the arrow in FIG. In the downstream part of the absorption pipe 51, the flow of the absorbent solution 61A and the refrigerant vapor 62A is adapted to a stress balance, so that a part of the excessive kinetic energy in the ejection part is recovered as an increase in static pressure.

In this thin liquid film portion 61A, the liquid film thickness becomes very thin, and the heat and mass transfer during absorption is greatly promoted. Moreover, since the speed can be made very large, the flow is disturbed and further absorption promotion is achieved. On the downstream side where the stress balance in the radial direction is taken, a thin liquid film corresponding to the degree of dryness is formed on the inner wall of the pipe, as in the ordinary annular gas-liquid two-phase flow. Even in this case, a thinner liquid film can be realized than a falling liquid film driven only by gravity. Moreover, generation | occurrence | production of the dry patch (dry surface) which became a problem with the falling liquid film type heat exchanger by the conventional gravity can be suppressed.
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a sectional view of an essential part of an absorber according to a second embodiment of the present invention. The second embodiment is different from the first embodiment in the points described below, and the other points are basically the same as those in the first embodiment, and thus redundant description is omitted.

  In the second embodiment, a spiral groove 59 is formed on the inner surface of the absorption tube 51, and a spiral groove 60 is formed on the inner surface of the refrigerant vapor introducing tube 55. Both spiral grooves 59 and 60 are formed in the same direction and at the same pitch.

  According to the second embodiment, since the helical groove 59 is formed on the inner surface of the absorption tube 51, the absorbent solution 61A sprayed into the absorption tube 59 can be swirled, The liquid film can be further thinned by centrifugal force. Furthermore, since the grooved surface of the absorption tube 51 also functions as an expansion fin, the heat transfer area increases with respect to the volume of the absorbent solution 61A that passes therethrough, and the liquid film thickness is substantially reduced. . For this reason, the big heat-transfer promotion effect is acquired.

Further, according to the second embodiment, since the spiral groove 60 is formed on the inner surface of the refrigerant vapor introducing pipe 55, the refrigerant vapor 62 also flows into the absorber 51 as a swirling flow. For this reason, the swirling flow in the absorber 51 can be generated more effectively, and further absorption promotion can be achieved.
(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a perspective view of an absorber according to a third embodiment of the present invention. The third embodiment is different from the first or second embodiment in the following points, and the other points are basically the same as those in the first or second embodiment, and thus overlap. Description is omitted.

  In the third embodiment, a plurality of absorption pipes 51 are installed vertically, and a plurality of enlarged fins 52 are provided on the outer surface of the absorption pipe 51. The expansion fins 52 are provided horizontally across the plurality of absorption tubes 51.

  According to the third embodiment, since the expansion fin 10 is provided on the outer surface of the absorption pipe 51, the absorber 5 can be directly cooled by the surrounding air 63. An air-cooled absorber can be realized, and a further reduction in size and size can be achieved.

  Further, according to the third embodiment, since the absorption pipe 51 is installed so as to extend in the direction of gravity, gravity is added to the flow of the absorbent solution 61A, and the flow rate can be further increased. .

  In the present invention, since the pressure of the supplied absorbent solution 61 is used as a driving force, for example, a high-pressure refrigerant that evaporates and absorbs at atmospheric pressure or higher, such as ammonia, chlorofluorocarbons, alcohols, dimethyl ether, propane, and butane is used. Accordingly, the absorption tube 51 can be either horizontal or vertical.

It is a block diagram of the absorption refrigerator of 1st Embodiment of this invention. It is sectional drawing of the introduction part part of the absorber solution and refrigerant | coolant vapor | steam in the absorber of 1st Embodiment of this invention. It is a principal part expansion explanatory drawing in the absorber of FIG. It is principal part sectional drawing of the absorber of 2nd Embodiment of this invention. It is a perspective view of the absorber of a 3rd embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... High temperature regenerator, 2 ... Low temperature regenerator, 3 ... Condenser, 4 ... Evaporator, 5 ... Absorber, 7 ... High temperature heat exchanger, 9 ... Solution pump, 10 ... Refrigerant pump, 11 ... Cold water, 12 ... Hot water heat exchanger, 13 ... hot water, 17 ... liquid heat exchanger, 19 ... solution pump, 21 ... pressure reducing means, 51 ... absorption pipe, 52 ... expansion fin, 53 ... solution introduction part, 54 ... inlet pipe, 55 ... refrigerant Steam introduction pipe, 56 ... Solution constriction part, 61 ... Absorbent solution, 61A ... Thin liquid film flow, 62 ... Refrigerant vapor, 63 ... Air.

Claims (5)

In the absorber that guides the absorbent solution and the refrigerant vapor into the absorption pipe and absorbs the refrigerant vapor in the absorbent solution and dissipates the absorption heat to the outside of the absorption pipe.
A solution introduction part for guiding the absorbent solution to the absorption pipe; and a refrigerant vapor introduction pipe for guiding the refrigerant vapor to the absorption pipe,
The outer surface of the refrigerant vapor introducing tube and the inner surface of the inlet portion of the absorption tube are formed to have a slight gap to form a solution contraction portion, and the inlet side of the solution contraction portion is connected to the inside of the solution introduction portion. An absorber which is configured to communicate and to eject the absorbent solution in an annular shape along the inner wall of the absorption tube from the solution constriction portion with the pressure of the absorbent solution.   The absorber according to claim 1, wherein a spiral groove is formed on an inner surface of the absorption tube.   The absorber according to claim 1 or 2, wherein a spiral groove is formed on an inner surface of the refrigerant vapor introducing pipe.   The absorber according to any one of claims 1 to 3, wherein a plurality of expansion fins are provided on an outer surface of the absorption tube.   An absorption refrigerator comprising the absorber according to claim 1.

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