JP2000002472A - Absorptive freezer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive the maintenance of a purity of a refrigerant of an absorptive freezer and the improvement of heat efficiency. SOLUTION: An absorber 2 absorbs the steam of a refrigerant produced in an evaporator 1, and generates the heat of absorption. A reproducer 3 heats absorber solution and extracts refrigerant steam so as to recover the concentration of the absorber solution. A distiller 6 provided on the reproducer 3 raises the purity of the refrigerant steam. The refrigerant steam extracted in the reproducer 3 is supplied to a condenser 9, with its purity raised with the distiller 6, and after condensation it is returned to the evaporator 1. For the refrigerant within the evaporator 1, the purity drops gradually, so its one part is extracted and is supplied to the head of the distiller 6. The refrigerant is let flow down through the distiller 6 for gas-liquid balancing reaction after being heat- exchanged with the refrigerant steam rising within the distiller 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption refrigeration apparatus, and more particularly to an absorption refrigeration apparatus that can maintain a high degree of refrigerant purity in an evaporator without lowering the thermal efficiency of the absorption refrigeration system.

[0002]

2. Description of the Related Art In an absorption refrigerator, a solution containing a refrigerant absorbed in an absorption liquid is separated into an absorption liquid and a refrigerant vapor in a regenerator and a rectifier, and the absorption liquid is recovered in the absorber. After the refrigerant vapor is condensed in the condenser, it is recovered in the evaporator and reused. Although the purity of the refrigerant supplied from the condenser to the evaporator is extremely high, only a small amount of the absorbent component mixed in the reflux refrigerant accumulates over a long operation cycle, and the purity of the refrigerant in the evaporator is increased. Inevitably declines.

[0003] Therefore, conventionally, a refrigerant liquid containing an absorbent component and having a reduced purity is withdrawn from the evaporator at a constant flow rate and fed to a regenerator together with the solution withdrawn from the absorber. Since the refrigerant fed to the regenerator is heated together with the solution to become a refrigerant vapor and collected in the evaporator, the purity of the refrigerant in the evaporator has been maintained at a high level.

[0004]

The conventional refrigerant purity maintaining method has the following problems. The greater the amount extracted from the evaporator, the higher the purity of the refrigerant. However, the refrigerant accumulated in the evaporator is originally a refrigerant liquid having a higher purity for use in the endothermic action, and such a refrigerant liquid is mixed into the absorbent solution without being used for the endothermic action. Therefore, there is a problem that the latent heat loss is large, and since the temperature of the refrigerant liquid is lowered, it is merged with the solution and heated and separated by the regenerator, resulting in a large heat loss. There is.

On the other hand, in a rectifier for further separating an absorbent component and a refrigerant in steam generated in a regenerator,
For the gas-liquid equilibrium reaction, a part of the refrigerant whose purity has been increased is supplied (refluxed) from the condenser to the enrichment section of the rectifier. It is also possible to cool the refrigerant vapor with the cooling water passed through the heat exchanger to condense and liquefy a part of the refrigerant vapor, that is, to reduce the refrigerant vapor. This condensate flows down from above the rectifier to make gas-liquid contact. Had been In this case, condensation and liquefaction can be performed satisfactorily, but a system for supplying cooling water is required, and heat loss due to release of heat to the cooling water occurs, resulting in a reduction in operating efficiency. There was a point.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an absorption refrigeration apparatus capable of maintaining a high degree of refrigerant purity in an evaporator and improving the thermal efficiency of an absorption refrigeration system.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems and achieve the object, the present invention provides an evaporator for accommodating a refrigerant and an absorbent solution for absorbing refrigerant vapor generated in the evaporator. An absorber to recover the absorbent concentration of the absorbent solution, a regenerator to heat the absorbent solution to extract refrigerant vapor, and a rectifier to increase the purity of the refrigerant vapor, A condenser for condensing the refrigerant vapor extracted by the regenerator and supplying it to the evaporator; and a pipe means for supplying a part of the refrigerant in the evaporator to the top of the rectifier. Comprising, after exchanging heat with the refrigerant vapor rising in the rectifier, the refrigerant supplied by the pipe means,
It is characterized in that it is configured to flow down in the rectifier.

According to the above feature, the refrigerant vapor ascending in the rectifier exchanges heat with the refrigerant supplied from the evaporator, and a part of the refrigerant vapor is liquefied and flows down the rectifier. The remainder of the purified refrigerant vapor is sent to a condenser.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a system block diagram showing a main configuration of an absorption refrigeration apparatus according to one embodiment of the present invention. Here, an absorption cooling and heating device is assumed as one embodiment of the absorption refrigeration device. In the evaporator 1, a fluorinated alcohol such as trifluoroethanol (TFE) is used as a refrigerant.
The absorber 2 contains a DMI derivative (dimethylimidazolidinone) as a solution containing an absorbent. The refrigerant is not limited to fluorinated alcohol, and may be any refrigerant that can have a wide non-freezing range. The solution is not limited to the DMI derivative, but can have a wide non-crystalline range, and may be any absorbent that has a higher normal pressure boiling point than TFE and can absorb TFE. On the other hand, a combination of water and lithium bromide may cause the water as a refrigerant to freeze due to a decrease in the temperature of the solution during the heating operation when the outside air temperature is near zero.
It is hard to say that it is suitable for the system of the present embodiment.

The evaporator 1 and the absorber 2 are fluidly connected to each other via an evaporation (refrigerant) passage having a precooler 18. Therefore, when the evaporator 1 and the absorber 2 are maintained in a low pressure environment of, for example, about 30 mmHg, the evaporator 1
The refrigerant in the inside evaporates and enters the absorber 2 through the evaporation passage. This refrigerant vapor is absorbed by the absorbent solution in the absorber 2, and an absorption refrigeration operation is performed. The precooler 18 functions to heat and vaporize the mist (mist-like refrigerant) remaining in the refrigerant vapor and to lower the temperature of TFE sent from the condenser 9.

During operation, first, the burner 7 is ignited, and the regenerator 3 increases the solution concentration in the absorber 2 (burner, regenerator and solution concentration will be described later). The evaporator 1 absorbs the refrigerant vapor and is cooled by the latent heat generated by the evaporation of the refrigerant. Inside 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 the # 1 of the first four-way valve V1.
At the opening, the other end (the inlet end in the figure) is the second four-way valve V2
No. 1 opening.

The refrigerant is guided by a pump P1 to a spraying means 1b provided in the evaporator 1, and is sprayed on a pipe 1a through which the cold water passes. The refrigerant removes the heat of evaporation from the cold water in the pipe line 1a, turns into refrigerant vapor, and flows into the absorber 2 through the evaporation passage. As a result, the temperature of the cold water in the pipe 1a drops. The refrigerant in the evaporator 1 is guided to the spraying means 1b, and a part of the refrigerant is supplied to the rectifier 6 through the filter 4 as described later. A flow control valve V5 is provided between the evaporator 1 and the filter 4.
As the cold water flowing through the pipe 1a, it is preferable to use an ethylene glycol or propylene glycol aqueous solution.

When the vapor of the fluorinated alcohol, that is, the refrigerant vapor is absorbed by the solution in the absorber 2, the temperature of the solution rises due to the heat of absorption. The absorption capacity of the solution increases as the temperature of the solution decreases and as the concentration of the absorbent increases. Therefore, in order to suppress a rise in the temperature of the solution, a pipe 2a is provided inside the absorber 2, and cooling water is passed through the pipe 2a. After passing through the condenser 9 at one end (outlet end in the figure) of the pipe line 2a, the # 4 of the first four-way valve V1 is
The other end (the inlet end in the figure) of the pipeline 2a is connected to the # 2 opening of the second four-way valve V2, respectively. As the cooling water passing through the pipe 2a, the same aqueous solution as the cold water is used.

The solution is guided by a pump P2 to a spraying means 2b provided in the absorber 2, and is sprayed on a pipeline 2a. As a result, the solution is cooled by the cooling water passing through the pipe 2a. On the other hand, the temperature of the cooling water rises because it absorbs heat. The solution in the absorber 2 absorbs the refrigerant vapor, and the absorption capacity decreases when the concentration of the absorbent decreases. Therefore,
By separating and generating the refrigerant vapor from the absorbent solution by the regenerator 3 and the rectifier 6, the concentration of the solution is increased and the absorption capacity is restored.

The solution diluted by absorbing the refrigerant vapor in the absorber 2, that is, the dilute solution, is guided to the spraying means 2 b, and is also fed to the rectifier 6 through the pipe 7 b by the pump P 2 to the regenerator 3. Flow down. An on-off valve V3 is provided in a pipe 7b connecting the pump P2 and the regenerator 3. The regenerator 3 has a burner 7 for heating the dilute solution supplied from the absorber 2. The burner 7 is preferably a gas burner, but may be any other type of heating means including utilization of exhaust heat. The solution (concentrated solution) heated by the regenerator 3 to increase the concentration by extracting the refrigerant vapor passes through the pipe 7a and passes through the absorber 2
Is returned to. An on-off valve V4 is provided on the pipeline 7a. At this time, the concentrated liquid having a relatively high temperature is sprayed on the pipeline 2a by the spraying means 2c.

When the diluted liquid supplied to the regenerator 3 is heated by the burner 7, refrigerant vapor is generated. The absorbent solution mixed into the refrigerant vapor is separated by the rectifier 6, and the refrigerant vapor having a higher purity is fed to the condenser 9.
The refrigerant cooled and condensed and liquefied there is supplied to the pre-cooler 1
8. Returned to the evaporator 1 via the pressure reducing valve 11 and sprayed.

Since the refrigerant vapor separated from the absorbent solution in the regenerator 3 and the rectifier 6 is condensed in the condenser 9 and supplied to the evaporator 1, the purity of the refrigerant is extremely high. . However, it is inevitable that the absorbent component that is very slightly mixed in the reflux refrigerant accumulates over a long operation cycle, and the purity of the refrigerant in the evaporator 1 gradually decreases. Therefore, in this embodiment, a very small portion of the refrigerant is introduced from the evaporator 1 to the top of the rectifier 6 via the filter 4 and the purity is increased again through the rectification cycle together with the refrigerant vapor generated from the regenerator 3. I did it.

The high-temperature concentrated liquid in the pipe 7a discharged from the regenerator 3 is discharged from the absorber 2 by the heat exchanger 12 provided in the middle of the pipe connecting the absorber 2 and the rectifier 6. After being cooled by exchanging heat with the dilute solution, it is sprayed into the absorber 2. on the other hand,
The dilute solution preliminarily heated in the heat exchanger 12 is supplied to the rectifier 6 to improve the thermal efficiency. Further, a heat exchanger (not shown) for transferring the heat of the concentrated liquid to be refluxed to the cooling water in the pipe 2a coming out of the absorber 2 or the condenser 9.
The temperature of the concentrated liquid refluxed to the absorber 2 can be further reduced, and the temperature of the cooling water can be further increased.

The sensible heat exchanger 14 for exchanging the cold water or the cooling water with the outside air is provided with a pipe 4a, and the indoor unit 15 is provided with a pipe 3a. One end (the inlet end in the figure) of each of the conduits 3a, 4a is at the opening # 3 and # 4 of the first four-way valve V1, and the other end (the outlet end in the figure) is the # of the second four-way valve V2.
3 and # 4 openings respectively. The indoor unit 15 is provided in a room that performs cooling and heating, and is provided with a cooling air or warm air blowing fan (both are common) 10 and a blowing outlet (not shown). The sensible heat exchanger 14 is placed outdoors, and the fan 19 forcibly exchanges heat with the outside air.

The evaporator 1 is provided with a level sensor L1 for detecting the amount of the refrigerant, a temperature sensor T1 for detecting the temperature of the refrigerant, and a pressure sensor PS1 for detecting the pressure in the evaporator 1. The absorber 2 is provided with a level sensor L2 for sensing the amount of the solution. The condenser 9 is provided with a level sensor L9 for sensing the amount of condensed refrigerant, a temperature sensor T9 for sensing the temperature of the refrigerant, and a pressure sensor PS9 for sensing the pressure in the condenser 9. Sensible heat exchanger 1
4, the regenerator 3, and the indoor unit 15 are provided with temperature sensors T14, T3, and T15, respectively. The temperature sensor T14 of the sensible heat exchanger 14 senses the outside air temperature, and the temperature sensor T15 of the indoor unit 15 senses the temperature of the room to be cooled and heated. The temperature sensor T3 of the regenerator 3 senses the temperature of the solution.

In the above configuration, during the cooling operation, the first and second four-way valves V1 and V2 are connected to the respective # 1 valves.
The opening and the # 3 openings are communicated and the # 2 and # 4 openings are communicated with each other. Thereby, the cold water whose temperature has been lowered by the refrigerant being sprayed on the pipeline 1a is guided to the pipeline 3a of the indoor unit 15 to cool the room.

On the other hand, 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. I do. Thereby, the warmed cooling water in the pipeline 2a is guided to the pipeline 3a of the indoor unit 15 to heat the room.

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 recirculation passage 9a and an on-off valve 17 are provided to bypass between the condenser 9 and the regenerator 3 (or the rectifier 6). That is, when it is difficult to pump up heat from the outside air, the absorption refrigeration cycle operation is stopped, the steam generated in the regenerator 3 is circulated to the condenser 9, and the heat generated by the burner 7 is transferred to the condenser 9. Thus, the temperature of the cooling water is increased by a direct fired operation in which the cooling water is efficiently transmitted to the cooling water in the pipe line 2a to improve the heating capacity.

If the user performs an operation for stopping the cooling / heating operation, almost all of the refrigerant in the condenser 9 is removed from the evaporator 1.
While the solution in the absorber 2 is almost entirely regenerated.
And then stop all operations. Thereby, the refrigerant vapor generated in the condenser 1 during the stoppage of operation is not absorbed by the regenerator 3, so that the concentration of the solution inside the regenerator 3 can be prevented from lowering. Further, it is possible to prevent the refrigerant in the evaporator 1 from being absorbed by the absorber 2.

The operation of the apparatus whose operation has been stopped in the above-described procedure is performed as follows. Assuming a cooling operation, first, the burner 7 is ignited to increase the pressure in the regenerator 3. Next, the pump P1 of the evaporator 1 and the pump P4 for circulating cold water are started. Refrigerant to be sprayed into the rectifier 6 is secured by the activation of the pump P1, and cold water is supplied to the indoor unit 15 by the activation of the pump P4. Then, when the pressure of the regenerator 3 rises, the on-off valve V4 is opened and the concentrated liquid is fed to the absorber 2. Subsequently, the pump of the cooling water system, that is, the pump P3 is started, and the heat of condensation and heat of absorption is radiated from the sensible heat exchanger 14 to start the cycle.

Next, the structure of the rectifier 6 will be described. FIG. 2 is an enlarged view of the rectifier 6. The rectifier 6 comprises a gas-liquid contact layer 60 packed with a packing of regular or irregular shape.
The diluted liquid supplied from the absorber 2 through the heat exchanger 12 flows down through the gas-liquid contact layer 60. The falling rare liquid contacts the refrigerant vapor rising from the regenerator 3 to improve the purity of the refrigerant vapor. A decompressor 61 is provided on the gas-liquid contact layer 60, and the refrigerant supplied from the evaporator 1 via the filter 4 and the refrigerant vapor rising through the gas-liquid contact layer 60 Is subjected to heat exchange to condense and liquefy a part of the refrigerant vapor.

A specific example of the decompressor 61 will be described. FIG.
FIG. 4 is a sectional view showing a main part of the decompressor 61, and FIG. The decompressor 61 has a refrigerant introduction pipe 62 for heat exchange and a gas-liquid separator 63 formed in a spiral shape. The refrigerant vapor rising from the gas-liquid separation layer 60 is
Absorber component in refrigerant vapor is cooled and liquefied by contact with 2,
The refrigerant vapor having improved purity is discharged upward and reaches the condenser 9. Here, since the refrigerant introduction pipe 62 has a spiral shape, the passage of the refrigerant vapor rising in the rectifier 6 is widely covered to facilitate the contact with the refrigerant vapor.

The details of the gas-liquid separator 63 are shown in a sectional view of a main part in FIG. 5 and a plan view in FIG. The gas-liquid separator 63 is a cylinder having an open bottom, and a hole 631 through which refrigerant vapor escapes is provided at the top, and the refrigerant introduction pipe 62 is fixed through the side wall. Refrigerant introduction pipe 62
Are positioned relative to the side wall such that the refrigerant discharged therefrom is introduced into the gas-liquid separator 62 from the tangential direction of the inner wall, instead of being directed to the center of the gas-liquid separator 63 (particularly, See FIG. 6). Since the refrigerant introduction pipe 62 is positioned as described above, the refrigerant flows along the inner periphery of the gas-liquid separator 63, so that the flow velocity is reduced and the refrigerant flows down. Among the refrigerant discharged into the gas-liquid separator 63 from the refrigerant introduction pipe 62, the liquid is dropped on the gas-liquid contact layer 60, and the vapor passes through the hole 631 and is supplied to the condenser 9.

FIG. 7 is a sectional view showing a modification of the divider 61, and FIG. 8 is a plan view of the same. In this modified example, the refrigerant introduction pipe 621 has a large diameter instead of being made spiral and long, and the fin 6 has a large diameter in order to increase the efficiency of heat exchange.
4 was formed. The connection between the gas-liquid separator 63 and the side wall thereof and the refrigerant introduction pipe 621 is the same as in FIGS.

The decompressor 61 is not limited to the above-described configuration. The refrigerant vapor passing through the gas-liquid contact layer 60 comes into contact with the refrigerant introduction pipe 62 through which the refrigerant passes, and a part of the refrigerant is liquefied. As long as the heat exchange function can be performed so that the refrigerant vapor becomes a highly purified refrigerant vapor, it is optional to deform along this purpose. For example, below the gas-liquid separator 63, a plate member for dispersing the flowing-down refrigerant and dropping it on the gas-liquid contact layer 60 can be provided.

Since the temperature of the refrigerant introduced into the refrigerant introduction pipe 62 is much lower than that of the refrigerant vapor that has risen in the thus configured condensing device 61, the absorption that is a high-boiling component in the refrigerant vapor is performed. The agent is selectively condensed, and a high shrinkage effect is obtained. Further, the refrigerant whose temperature has risen by absorbing heat from the refrigerant vapor is partially vaporized, and the remaining refrigerant is supplied to the refrigerant introduction pipe 6.
The gas flows down the gas-liquid contact layer 60 together with the liquid condensed on the outer wall surface of No. 2 to perform a rectification action.

In the present embodiment, unlike the conventional one in which cooling water is separately introduced from the outside to exchange heat with refrigerant vapor,
The rectification and the contraction of the refrigerant vapor can be performed efficiently without discarding heat to the outside. Further, unlike the conventional refrigerant in which the refrigerant extracted from the evaporator 1 is combined with the dilute liquid and supplied to the regenerator 2, the latent heat is not wasted.

[0033]

As is clear from the above description, the present invention has the following effects. (1) The refrigerant vapor can be reduced by the temperature difference between the refrigerant extracted from the evaporator and the refrigerant vapor in the rectifier. (2) Since the refrigerant extracted from the evaporator can be used as the gas-liquid contact liquid necessary for rectification, the latent heat of the refrigerant can be used effectively, and the purity of the refrigerant can be maintained, resulting in a system. Thermal efficiency can be improved. (3) Since it is not necessary to exchange heat with the outside in order to maintain the purity of the refrigerant in the evaporator, the heat loss is small and the operation efficiency of the system can be increased.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a configuration of an absorption type cooling and heating apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a main part of a rectifier.

FIG. 3 is a sectional view showing an example of a heat exchanger at the top of a rectifier tower.

FIG. 4 is a plan view of a heat exchanger.

FIG. 5 is a sectional view of a gas-liquid separator.

FIG. 6 is a plan view of a gas-liquid separator.

FIG. 7 is a cross-sectional view showing a modification of the heat exchanger at the top of the rectifier tower.

FIG. 8 is a plan view according to a modification of the heat exchanger.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Evaporator, 2 ... Absorber, 3 ... Regenerator, 6 ... Rectifier, 9 ... Condenser, 14 ... Sensible heat exchanger, 60 ... Gas-liquid contact layer, 61 ... Divider, 62 ... Refrigerant introduction Tube, 63 ...
Gas-liquid separator, 64 fins

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Hidetaka Kayanuma 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Inventor Mitsuru Ishikawa 1-4-1 Chuo, Wako-shi, Saitama No. Within Honda R & D Co., Ltd. (72) Masami Sakamoto, Inventor 1-7-1, Nakase, Mihama-ku, Chiba-shi, Chiba F-term in Sumitomo Chemical Engineering Co., Ltd. 3L093 AA01 BB01 BB22 BB29 BB31 BB37 BB49 LL01 MM02

Claims (5)

[Claims] 1. An evaporator for storing a refrigerant, an absorber for storing an absorbent solution for absorbing refrigerant vapor generated in the evaporator, and an absorbent for recovering the absorbent concentration of the absorbent solution. A regenerator for heating the solution to extract the refrigerant vapor, a rectifier for increasing the purity of the refrigerant vapor, and a condensation for condensing the refrigerant vapor extracted by the regenerator and supplying the refrigerant vapor to the evaporator Vessel, and a pipe means for feeding a part of the refrigerant in the evaporator to the top of the rectifier, the refrigerant supplied by the pipe means, in the rectifier An absorption refrigeration apparatus characterized in that the refrigeration apparatus is configured to exchange heat with rising refrigerant vapor and then flow down the rectifier. 2. A heat exchanger having a pipe through which the refrigerant supplied by the pipe means passes, and the refrigerant vapor rising in the rectifier is passed through the pipe via the pipe. 2. The absorption refrigeration apparatus according to claim 1, wherein heat is exchanged with the refrigerant in the road. 3. The pipe means is a spiral pipe having a winding diameter decreasing from the outer wall side of the rectifier to the center, and a refrigerant outlet located near the center. Item 3. An absorption refrigeration apparatus according to item 1 or 2. 4. The absorption refrigeration system according to claim 1, further comprising a fin formed on an outer surface of the pipeline. 5. The gas-liquid separator according to claim 1, wherein a ceiling has a vapor vent hole, and a side wall is provided with a cylindrical gas-liquid separator fixedly penetrating the end of the conduit. An absorption refrigeration apparatus according to any one of the above.