JP3966443B2 - Absorption refrigeration system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an absorption refrigeration apparatus, and more particularly, to an absorption refrigeration apparatus that can favorably maintain the purity of a refrigerant liquid contained in an evaporator.
[0002]
[Prior art]
In the absorption refrigeration apparatus, the absorbent solution (dilute) diluted by absorbing the refrigerant vapor with the absorber is sent to the regenerator. The absorbent solution whose concentration has been increased by extracting the refrigerant in the regenerator is returned to the absorber. On the other hand, the refrigerant vapor extracted from the absorbent solution is condensed by the condenser to become a refrigerant liquid and sent to the evaporator. Although the purity of the refrigerant liquid sent to the evaporator is increased, the slightly mixed absorbent is accumulated during the long-term operation, and gradually decreases the purity of the refrigerant liquid in the evaporator. In order to prevent the purity of the refrigerant liquid from being lowered, it is generally performed that a predetermined amount of the refrigerant liquid in the evaporator is extracted and sent to the rectifier.
[0003]
[Problems to be solved by the invention]
A conduit (bleed tube) for feeding the refrigerant liquid from the evaporator to the rectifier is a relatively thin tube because it feeds a small amount of refrigerant, but its length is long. Therefore, it is easy to be affected by the temperature of the arrangement environment, and it is necessary to eliminate the thermal influence from the environment by winding a heat insulating material or the like.
[0004]
In addition, since the environment in which the bleed pipe is piped, that is, the atmosphere, is at a relatively higher pressure than in the bleed pipe, it is necessary to maintain the degree of vacuum in the bleed pipe by managing the bleed pipe at a predetermined leak rate. For example, it was necessary to devise the joint in order to ensure a pressure of 50 mmHg or less, or to strictly control the leak rate of the bleed pipe itself.
[0005]
An object of the present invention is to provide an absorption refrigeration apparatus capable of facilitating the management of the thermal influence and the leak rate on the bleed pipe as described above.
[0006]
[Means for Solving the Problems]
The present invention provides an evaporator that stores a refrigerant liquid, an absorber that absorbs refrigerant vapor generated in the evaporator with an absorbent solution, and an absorbent solution for recovering the absorbent concentration of the absorbent solution. A regenerator for extracting refrigerant vapor by heating, a rectifier for rectifying the refrigerant vapor extracted by the regenerator, and condensing the refrigerant vapor rectified by the rectifier and supplying it to the evaporator And a bleed line for feeding a part of the refrigerant liquid from the evaporator to the upper part of the rectifier in order to use the refrigerant liquid in the evaporator as a gas-liquid contact liquid in the rectifier. There is a first feature in that the bleed conduit is piped so as to pass through the absorber and from the evaporator to the rectifier.
[0007]
The present invention further includes an air cooling unit including a sensible heat exchanger for exchanging heat with the outside air and a cooling fan disposed opposite to the sensible heat exchanger, and the regenerator and the rectifier include a sensible heat exchanger. With the distiller up and the regenerator down, it is arranged on the side of the air cooling unit, the absorber is arranged on the air cooling unit, and the rectification is performed from the inner end of the absorber. A second feature is that the bleed pipe is piped in the upper part of the chamber.
[0008]
Further, according to the present invention, the evaporator is disposed adjacent to the side opposite to the regenerator with respect to the air-cooling unit, and passes through the evaporator so that the refrigerant in the evaporator A refrigerant liquid circulation line that circulates the liquid in the upper part, and the refrigerant liquid circulation line is branched into a spraying means to the inside of the evaporator and the bleed line in the upper part of the evaporator. There are features.
[0009]
According to the first feature, the bleed pipe is placed in a low pressure, stable and relatively high temperature environment in the absorber, so that the temperature control of the bleed pipe is easy and the leak rate is also managed. Easy. Moreover, the temperature of the refrigerant liquid from the evaporator is raised by heat exchange in the absorber and fed to the rectifier, so that the rectification efficiency is not hindered and the effect of cooling the absorber can be obtained.
[0010]
In addition, according to the second feature, since the refrigerant liquid can be fed from the absorber to the rectifier at a short distance, it is difficult to be influenced by the outside air, so that the thermal efficiency is good. Further, the heat exchange component is arranged compactly around the air cooling unit.
[0011]
Further, according to the third feature, since the bleed pipe is branched from the spraying means portion in the upper part of the evaporator, the bleed pipe line leading to the inside of the absorber can be shortened.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 2 is a system block diagram showing a main configuration of an absorption refrigeration apparatus according to an embodiment of the present invention. Here, an absorption cooling / heating device is assumed as an embodiment of the absorption refrigeration apparatus. The evaporator 1 contains a fluorinated alcohol such as trifluoroethanol (TFE) as a refrigerant, and the absorber 2 contains dimethylimidazolidinone (DMI) or a derivative thereof as a solution containing an absorbent. The refrigerant is not limited to the fluorinated alcohol, but may be any one that can take a wide non-freezing range, and the solution is not limited to the DMI derivative and can take a wide non-crystalline range, and has a normal pressure boiling point higher than that of TFE. It may be an absorbent that has TFE and can absorb TFE.
[0013]
The evaporator 1 and the absorber 2 are fluidly connected to each other via an evaporation (refrigerant) passage (not shown). If these spaces are maintained in a low-pressure environment of about 30 mmHg, for example, the refrigerant in the evaporator 1 Evaporates and enters the absorber 2 through the passage. A precooler 18 is provided to heat and vaporize the mist (mist refrigerant) remaining in the refrigerant vapor, and to lower the temperature of the TFE fed from the condenser 9. The refrigerant solution is absorbed by the absorbent solution in the absorber 2 and the absorption refrigeration operation is performed.
[0014]
First, when the burner 7 is ignited and the concentration of the solution in the absorber 2 is increased by the regenerator 3 (the burner and the regenerator and solution concentration will be described later), the solution in the absorber 2 absorbs the refrigerant vapor, The inside of the evaporator 1 is cooled by the latent heat due to the evaporation of the refrigerant. In the evaporator 1, a pipe line 1a through which cold water passes is provided. One end (outlet end in the figure) of the pipe line 1a is connected to the # 1 opening of the first four-way valve V1, and the other end (inlet end in the figure) is connected to the # 1 opening of the second four-way valve V2.
[0015]
The refrigerant is guided to the spraying means 1b provided in the evaporator 1 by the pump P1, and sprayed onto the pipe line 1a through which the cold water passes. The refrigerant removes heat of evaporation from the cold water in the pipe 1a to become refrigerant vapor, and flows into the absorber 2 through the evaporation passage. As a result, the temperature of the cold water in the pipe line 1a falls. In addition to being guided to the spraying means, a part of the refrigerant in the evaporator 1 passes through the filter 4 and is fed to the rectifier 6 as a gas-liquid contact liquid (hereinafter referred to as “bleed”) as will be described later. The A flow control valve V5 is provided between the evaporator 1 and the filter 4. The supply amount of the bleed can be adjusted by controlling the discharge amount of the pump P1, and the opening degree of the flow rate adjusting valve V5 can be varied (for example, switching between two levels), and can be changed by this switching. As the cold water flowing through the pipe line 1a, it is preferable to use ethylene glycol or propylene glycol aqueous solution.
[0016]
When the fluorinated alcohol vapor, that is, the refrigerant vapor is absorbed by the solution of the absorber 2, the temperature of the solution rises due to the heat of absorption. The absorption capacity of the solution is higher as the temperature of the solution is lower and as the solution concentration is higher. Therefore, in order to suppress the temperature rise of the solution, a pipe 2a is provided inside the absorber 2, and cooling water is passed through the pipe 2a. One end (outlet end in the figure) of the pipe line 2a passes through the condenser 9, and then passes to the # 2 opening of the first four-way valve V1 via the pump P3, and the other end (inlet end in the figure) of the pipe line 2a. Are respectively connected to the # 2 opening of the second four-way valve V2. The same aqueous solution as the cold water is used as the cooling water passing through the pipe line 2a.
[0017]
The solution is guided to the spraying means 2b provided in the absorber 2 by the pump P2, and sprayed onto the pipe line 2a. As a result, the solution is cooled by the cooling water passing through the pipe line 2a. On the other hand, since the cooling water absorbs heat, its temperature rises. When the solution in the absorber 2 absorbs the refrigerant vapor and the concentration of the absorbent decreases, the absorption capacity decreases. Therefore, the refrigerant vapor is separated and generated from the absorbent solution in the regenerator 3 and the rectifier 6, thereby increasing the concentration of the solution and restoring the absorption capacity.
[0018]
The solution diluted by absorbing the vapor of the refrigerant in the absorber 2, that is, the diluted solution, is guided to the spraying means 2b, and is fed to the rectifier 6 through the pipe 7b by the pump P2 and flows down to the regenerator 3. . The regenerator 3 has a burner 7 for heating the dilute liquid supplied from the absorber 2. The burner 7 is preferably a gas burner, but may be any other type of heating means. The solution (concentrated liquid) heated by the regenerator 3 and having the concentration increased by extracting the refrigerant vapor is returned to the absorber 2 through the pipe line 7a. An on-off valve V4 is provided on the pipe line 7a, and the concentrated liquid is sprayed on the pipe line 2a by the spraying means 2c.
[0019]
When the dilute liquid fed to the regenerator 3 is heated by the burner 7, refrigerant vapor is generated. This refrigerant vapor is sent to the rectifier 6, and the absorbent solution mixed therein is separated. In this way, the refrigerant vapor with higher purity is fed to the condenser 9. The refrigerant cooled by the condenser 9 and condensed and liquefied is sent to the evaporator 1 via the precooler 18 and the pressure reducing valve 11 and is dispersed on the pipe line 1a.
[0020]
Although the purity of the refrigerant supplied from the condenser 9 to the evaporator 1 is extremely high, an extremely small amount of the absorbent component is mixed. It is inevitable that the absorbent component accumulates due to a long operation cycle and the purity of the refrigerant in the evaporator 1 gradually decreases. Therefore, as described above, a small part of the refrigerant is fed from the evaporator 1 to the rectifier 6 through the filter 4 and goes through a cycle for raising the purity together with the refrigerant vapor generated from the regenerator 3. ing.
[0021]
The high temperature concentrated liquid in the pipe line 7a that has come out of the regenerator 3 is separated from the dilute liquid that has come out of the absorber 2 by a heat exchanger 12 provided in the middle of the pipe line that connects the absorber 2 and the rectifier 6. After being cooled by heat exchange, it is collected in the absorber 2. On the other hand, the dilute liquid preliminarily heated by the heat exchanger 12 is fed to the regenerator 3. In this way, the heat efficiency is improved. Furthermore, a heat exchanger (not shown) is used to transmit the heat of the concentrated liquid to be recirculated to the cooling water in the pipe 2a exiting from the absorber 2 or the condenser 9. 2), the temperature of the concentrated liquid refluxed to the absorber 2 may be further reduced, and the cooling water temperature may be further increased.
[0022]
A pipe 4a is passed through the sensible heat exchanger 14 for exchanging heat between the cold water or the cooling water and the outside air, and a pipe 3a is provided in the indoor unit 15. Each end (inlet in the figure) of the pipes 3a, 4a is # 3, 4 opening of the first four-way valve V1, and the other end (outlet end in the figure) is # 3, 4 opening of the second four-way valve V2. Respectively. The indoor unit 15 is provided in a room that performs cooling and heating, and is provided with a fan for blowing cold air or hot air (both are common) 10 and an outlet (not shown). The sensible heat exchanger 14 is placed outside and the fan 19 forcibly exchanges heat with the outside air.
[0023]
The evaporator 1 is provided with a level sensor L1 for sensing the amount of refrigerant and a temperature sensor T1 for sensing the temperature of the refrigerant. The absorber 2 is provided with a level sensor L2 that senses the amount of the solution. The condenser 9 is provided with a level sensor L9 that senses the amount of the condensed refrigerant, a temperature sensor T9 that senses the temperature of the refrigerant, and a pressure sensor PS9 that senses the pressure in the condenser 9.
[0024]
The sensible heat exchanger 14 has a temperature sensor T14 that senses the outside air temperature, the indoor unit 15 has a temperature sensor T15 that senses the temperature of the air-conditioning room, and the regenerator 3 has a temperature sensor T3 that senses the temperature of the solution. Are provided. Furthermore, a temperature sensor T6 is provided at the top of the rectifier 6 to detect the internal atmospheric temperature, that is, the temperature of the refrigerant vapor rectified by the rectifier 6 (top temperature).
[0025]
During the cooling operation, the first and second four-way valves V1 and V2 are switched to positions where the # 1 and # 3 openings are communicated and the # 2 and # 4 openings are communicated. As a result, the cold water whose temperature has been lowered by spraying the refrigerant on the pipe line 1a is guided to the pipe line 3a of the indoor unit 15 to cool the room.
[0026]
During the heating operation, the first and second four-way valves V1 and V2 are switched to positions where the # 1 and # 4 openings are communicated and the # 2 and # 3 openings are communicated. Thereby, the warmed cooling water in the pipe line 2a is led to the pipe line 3a of the indoor unit 15, and the room is heated.
[0027]
If the outside air temperature becomes extremely low during the heating operation, it becomes difficult to pump heat from the outside air through the sensible heat exchanger 14, and the heating capacity is reduced. For such a case, a reflux passage 9a and an on-off valve 17 are provided to bypass between the condenser 9 and the regenerator 3 (or the rectifier 6). Thus, when it is difficult to pump heat from the outside air, the absorption refrigeration cycle operation is stopped, the steam generated in the regenerator 3 is circulated to and from the condenser 9, and the amount of heat generated by the burner 7 is reduced in the condenser 9. In order to improve the heating capacity, the temperature of the cooling water is raised by a direct-fired operation that is efficiently conducted to the cooling water in the pipe 2a.
[0028]
The concentration of the dilute liquid fed from the absorber 2 to the regenerator 3 varies depending on the outside air condition and the load state. Therefore, in order to maintain the purity of the refrigerant vapor at the top of the rectifier 6 well and to maintain the purity of the refrigerant liquid fed to the evaporator 1 at a high level, the purity of the refrigerant liquid is increased along with the change of the dilute liquid concentration. It is necessary to change the amount of bleed supplied to the distillation apparatus 6. Therefore, the discharge amount of the pump P1 can be controlled based on the tower top temperature of the rectifier 6 by the temperature sensor T6, and the supply amount of the bleed can be adjusted. Regarding the bleed supply amount control, the description of Japanese Patent Laid-Open No. 2000-55503 is incorporated herein, and detailed description thereof is omitted.
[0029]
FIG. 3 is a perspective view of the absorption type air conditioner, showing a state where a cover is partially removed so that the arrangement of the main part can be observed. 2, the same reference numerals as those in FIG. 2 denote the same parts, and only the main parts of the support members and piping are shown. This absorption type air conditioner has a substantially rectangular parallelepiped shape as a whole, and a fan 19 having an axis extending in the F and B directions indicated by arrows A, that is, in the front-rear direction of the casing 20 is disposed in the central portion of the rectangular casing 20. . The sensible heat exchanger 14 is disposed behind the fan 19, that is, adjacent to the direction B shown by the arrow A (not shown). The fan 19 is surrounded by a cylindrical air guide path 21 that guides the wind generated by the fan 19 to the sensible heat exchanger 14.
[0030]
A regenerator 3 is disposed on the lower side of the housing 20 on the right side (R direction indicated by arrow A). A cylindrical rectifier 6 extending upward along the right wall surface of the housing is disposed above the regenerator 3. Be placed. A heat exchanger 12 is ligated to the rectifier 6.
[0031]
On the other hand, the evaporator 1 is disposed vertically on the wall surface on the left side (L direction indicated by the arrow) of the housing 20. Above the evaporator 1, an absorber 2 is disposed so as to lie adjacent to the top of the evaporator 1 and extend from the evaporator 1 toward the right side of the housing 20. Above the absorber 2, that is, in the vicinity of the upper surface of the housing 20, the condenser 9 is disposed horizontally along the absorber 2.
[0032]
The top of the rectifier 6 and the right end of the condenser 9 are connected to each other by a connecting pipe 23 in order to introduce refrigerant vapor from the rectifier 6 to the condenser 9. Further, a conduit (bleed pipe) 24 for feeding the refrigerant liquid as a bleed from the evaporator 1 to the top of the rectifier 6 passes through the inside of the absorber 2 and extends from the right end of the absorber 2. Projects and is coupled to the rectifier 6.
[0033]
A cooling water circulation pump P <b> 3 is provided in the lower left portion of the housing 20. The pump P4 is disposed behind the pump P3. Further, a pump P1 for circulating the solution is disposed below the evaporator 1. A conduit 30 drawn from the pump P1 passes through the evaporator 1 and extends upward, and is branched and connected to the bleed pipe 24 as will be described later. As described above, the fan 19 and the sensible heat exchanger 14 are arranged in the center, and the main components are housed in a compact space in the space between the fan 19 and the sensible heat exchanger 14.
[0034]
FIG. 4 is a view (rear view) of the evaporator 1, the absorber 2 and the condenser 9 as viewed from the back side, that is, the B side of the arrow A. FIG. 1 is a perspective view of the evaporator 1 and the absorber 2 and shows a state in which the cover is removed. In both figures, the evaporator 1, the absorber 2 and the condenser 9 are provided with heat exchange cores 25, 26 and 27. The cores 25, 26, and 27 are formed by arranging a large number of thin plates, and cooling water pipes are provided through the thin plates. At the side portions of the cores 25, 26, 27, inlets 251, 261, 271 and outlets 252, 262, 272 of the respective cooling water pipes are provided so as to protrude. Above the core 25 of the evaporator 24 is provided spraying means or spray 1b for recirculating the refrigerant, above the absorber 2, spraying means or spray 2b for recycling the solution, and the regenerator 2 And a spray 2c as means for spraying the concentrated liquid circulating from the core 26 to the core 26.
[0035]
A pump P1 is connected to the solution outlet 28 of the evaporator 1, and a conduit 30 connected to the outlet 29 of the pump P1 extends upward along the core 25 and is connected to a branch joint 31. One of the conduits 30 branched at the joint 31 is connected to the spray 1b and the other extends as a bleed tube 24 in the absorber 2 along the core 26 to the end of the absorber 2, as described with reference to FIG. It reaches the top of the rectifier 6.
[0036]
A pump P2 is arranged on the side of the evaporator 1, and a conduit 32 for introducing a solution from the absorber 2 is connected to the inlet of the pump P2. An upwardly extending conduit 33 is connected to the outlet of the pump P2, and this conduit 33 is branched at a joint 34 into a spray 2b side and a conduit 35 which is a part of a conduit 7b extending to the heat exchanger 12.
[0037]
A precooler 18 is provided between the evaporator 1 and the absorber 2. A conduit 36 for feeding the refrigerant liquid from the condenser 9 passes through the absorber 2 and is connected to the precooler 18. A conduit 37 connected to the outlet side of the precooler 18 extends on the core 25 of the evaporator 1 via the pressure reducing valve 11 and guides the refrigerant liquid into the evaporator 1.
[0038]
【The invention's effect】
According to the present invention, since the bleed pipe line is placed in a stable temperature environment inside the absorber, it is not necessary to take measures against thermal influences from the external environment such as winding a heat insulating material. In addition, since the refrigerant liquid is heat-exchanged in a relatively high temperature atmosphere in the absorber and the temperature rises, there is also an effect of cooling the absorber. Furthermore, since the bleed pipe is piped in an absorber that is a low-pressure environment of, for example, 10 mmHg to 30 mmHg, it is easy to hold the pipe in a state close to a vacuum.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a main part of an air conditioning apparatus according to an embodiment of the present invention.
FIG. 2 is a system block diagram showing a configuration of an air conditioner according to an embodiment of the present invention.
FIG. 3 is a perspective view of the air conditioning apparatus according to the embodiment of the present invention.
FIG. 4 is a main part rear view of the air-conditioning apparatus according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Evaporator, 1a ... Pipe for cold water, 2 ... Absorber, 2a ... Pipe for cooling water 3 ... Regenerator, 4 ... Filter, 6 ... Rectifier, 9 ... Condenser, 12 ... Heat exchanger, DESCRIPTION OF SYMBOLS 14 ... Sensible heat exchanger, 19 ... Fan, 20 ... Housing, 21 ... Air guide path, 23 ... Connecting pipe, 24 ... Bleed pipe, 25, 26, 27 ... Core, 28 ... Solution outlet

Claims (3)

An evaporator containing a refrigerant liquid; an absorber that absorbs refrigerant vapor generated in the evaporator with an absorbent solution;
In order to recover the absorbent concentration of the absorbent solution, a regenerator that heats the absorbent solution and extracts refrigerant vapor;
A rectifier for rectifying the refrigerant vapor extracted by the regenerator;
A condenser that condenses the refrigerant vapor rectified by the rectifier and supplies the condensed vapor to the evaporator;
In order to use the refrigerant liquid in the evaporator as a gas-liquid contact liquid in the rectifier, the bleed pipe for feeding a part of the refrigerant liquid from the evaporator to the upper part of the rectifier,
The absorption refrigeration apparatus, wherein the bleed pipe is connected to the evaporator so as to pass from the evaporator to the rectifier. A sensible heat exchanger for exchanging heat with the outside air, and an air cooling unit comprising a cooling fan disposed opposite to the sensible heat exchanger,
The regenerator and the rectifier are arranged on the side of the air cooling unit with the rectifier on top and the regenerator on the bottom,
The absorption refrigeration apparatus according to claim 1, wherein the absorber is disposed on the air cooling section, and the bleed pipe is piped from an inner end of the absorber to an upper portion of the rectifier. The evaporator is disposed adjacent to the side opposite to the regenerator with respect to the air cooling unit, and
A refrigerant liquid circulation line for passing through the inside of the evaporator and circulating the refrigerant liquid in the evaporator upward;
3. The absorption refrigeration apparatus according to claim 2, wherein the refrigerant liquid circulation pipe is branched into a spraying means to the inside of the evaporator and the bleed pipe in the upper part of the evaporator.

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