JP2001317835A - Absorption refrigeration machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a refrigerant in a high temperature evaporator and cooling water cooled in the high temperature evaporator from being frozen in an absorption refrigerating machine which includes two stages of the evaporators and two stages of the absorbers. SOLUTION: The absorption refrigerating machine 200 includes a low temperature evaporator 1, a low temperature absorber 2, a high temperature evaporator 3, and a high temperature absorber 4. A solution heated and condensed in a high temperature regenerator 7 and a low temperature regenerator 6 is guided to an intermediate temperature solution heat exchanger 9. The solution is heat- exchanged with a solution guided from the low temperature absorber and the high temperature absorber in the intermediate temperature solution heat exchanger, and then part thereof is guided to the side of the low temperature absorber with the remaining part guided to the side of the high temperature absorber. The amount of the solution guided to the side of the low temperature absorber is controlled by a control device 100 using a control valve 45a. When at least any of the refrigerant temperature, heat transfer medium temperature, and cooling water temperature is lowered to a predetermined temperature, the control valve is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to an absorption refrigerator having two sets of evaporators and absorbers.

[0002]

2. Description of the Related Art A conventional absorption refrigerator is disclosed in, for example,
As described in JP-A-1-304277, all of the absorption solutions concentrated in the high-temperature regenerator and the low-temperature regenerator are led to the high-temperature absorber. Then, the solution flowing out of the high-temperature absorber is guided to the low-temperature absorber via the heating side of the low-temperature solution heat exchanger. As a result, the inlet concentration of the absorbing solution in the low temperature absorber is made the same as the outlet concentration of the absorbing solution in the high temperature absorber. In addition, the heating side of the high-temperature evaporator and the heated side of the low-temperature absorber are connected by a pipe to transfer the heat of evaporation and the heat of absorption.

[0003]

In the absorption refrigerator described in the above publication, when the temperature of the cooling water supplied to the high-temperature absorber decreases, the pressure in the high-temperature evaporator decreases, and the refrigerant may freeze. is there. Therefore, it is necessary to set the lower limit of the cooling water temperature high, and the allowable range of the cooling water temperature is small.
Also, if the amount of heat input to the high-temperature regenerator is reduced to avoid refrigerant freezing, the amount of heat transfer in the low-temperature evaporator decreases,
The desired refrigeration capacity cannot be obtained. Furthermore, if the temperature level of the entire absorption cycle is increased to avoid freezing of the refrigerant, the evaporation temperature of the low-temperature evaporator also increases, and a desired refrigeration temperature cannot be obtained.

Further, in the absorption refrigerator described in Japanese Patent Application Laid-Open No. H11-304277, the heating side of the high-temperature evaporator and the heated side of the low-temperature absorber are connected, so that the heat transfer medium flowing in the pipe is widely used. If the employed water (cooling water) is used, there is a possibility that the temperature in the pipe is lowered and the water flowing in the pipe of the high-temperature evaporator is frozen. If the heat transfer tube in the high-temperature evaporator is damaged, vacuum breakage occurs, which causes a failure of the absorption refrigerator. If an antifreeze such as brine is used as the heat transfer medium to avoid this problem, the cost increases. In addition, when the heat transfer medium is changed from water to another medium, the heat transfer performance is reduced, which causes an increase in the heat transfer area and an increase in the size of the evaporator.

The present invention has been made in view of the above-mentioned disadvantages of the related art, and has as its object to prevent freezing of a refrigerant and a heat transfer medium in an absorption refrigerator. Another object of the present invention is to realize a highly reliable absorption refrigerator capable of extracting cold heat equal to or lower than ice temperature. In the present invention, at least one of these objects may be achieved.

[0006]

A first feature of the present invention to achieve the above object is to provide a regenerator, a condenser, a high-temperature evaporator, a low-temperature evaporator, a high-temperature absorber, and an absorption device having a low-temperature absorber. In the refrigerator, the concentrated solution heated and condensed in the regenerator
A first heat exchanger that absorbs the refrigerant with the low-temperature absorber and the high-temperature absorber and exchanges heat with the diluted solution that has been diluted, and guides the concentrated solution cooled by exchanging heat with the heat exchanger to the high-temperature absorber; And a second flow path leading to the low-temperature absorber.

Preferably, a flow rate control means is provided in the second flow path; a refrigerant temperature detection means for detecting a refrigerant temperature is provided in the high-temperature evaporator, and the refrigerant temperature is determined based on the refrigerant temperature detected by the detection means. It controls the flow control means.

A second feature of the present invention to achieve the above object is that a regenerator, a condenser, a high-temperature evaporator, a low-temperature evaporator, a high-temperature absorber through which cooling water flows, and an absorption device having a low-temperature absorber. In the refrigerator, a refrigerant temperature detecting means for detecting a refrigerant temperature of the high-temperature evaporator, and at least one of a temperature and a flow rate of cooling water flowing through the high-temperature absorber based on the refrigerant temperature detected by the refrigerant detecting means. And a control device.

A third feature of the present invention to achieve the above object is that a regenerator, a condenser, a high-temperature evaporator, a low-temperature evaporator, a high-temperature absorber through which cooling water flows, and an absorption device having a low-temperature absorber In the refrigerator, a circulation path for circulating the heat transfer medium between the high-temperature evaporator and the low-temperature absorber is formed, and a heat transfer medium temperature detection means for detecting the temperature of the heat transfer medium is provided in the circulation path. And a control device for controlling at least one of the temperature and the flow rate of the cooling water flowing through the high-temperature absorber based on the detected heat transfer medium temperature.

A fourth feature of the present invention to achieve the above object is that a high-temperature regenerator, a low-temperature regenerator, a condenser, a high-temperature evaporator, a low-temperature evaporator, a high-temperature absorber through which cooling water flows, and a low-temperature absorber are provided. In the absorption refrigerator provided with, a circulation path through which the heat transfer medium circulates between the high-temperature evaporator and the low-temperature absorber, a heat transfer medium temperature detecting means for detecting the temperature of the heat transfer medium provided in the circulation path, A bypass pipe connecting the cooling water inlet of the absorber to a position downstream of the outlet from which the cooling water flows out of the high-temperature absorber, a flow control means provided in the bypass pipe, and a transmission line detected by the temperature detecting means. A control device that controls the flow rate of the cooling water flowing through the high-temperature absorber based on the temperature of the heat medium using flow rate control means. And
In each of the above features, it is desirable that the refrigerant is water and the solution is a lithium bromide aqueous solution.

A fifth feature of the present invention that achieves the above object is that water is used as a refrigerant and lithium bromide is used as an absorbent, and is provided with a high-temperature absorber, a low-temperature absorber, a high-temperature evaporator, and a low-temperature evaporator. In the refrigerating machine, control means is provided for making the concentration of the solution flowing into the low-temperature absorber higher than the concentration of the solution flowing out of the high-temperature absorber.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an absorption refrigerator according to the present invention will be described below with reference to FIG. Absorption refrigerator 200
Low temperature evaporator 1, Low temperature absorber 2, High temperature evaporator 3, High temperature absorber 4, Condenser 5, Low temperature regenerator 6, High temperature regenerator 7, Low temperature solution heat exchanger 8, Medium temperature solution heat exchanger 9, High temperature solution The heat exchanger 10 and the drain cooler 71 are provided. The inside of the absorption refrigerator 200 is filled with a refrigerant and an absorption solution as working fluids. The refrigerant is water and the absorbing solution is an aqueous solution of lithium bromide. Each of the above devices constituting the absorption refrigerator 200 is
They are connected by piping. In the piping, there is a solution pump 2
1, 41, 61, dilute solution pump 12, refrigerant pump 3
1. A heat medium pump 33 and a cooling water pump 43 are provided. In addition, temperature sensors 14, 34, 35, and 44 for detecting the temperature of the working fluid flowing through the pipe or the inside thereof are mounted in the pipe or in the vicinity of the pipe.

In the absorption refrigerator 200 thus configured, the refrigerant is heated and separated from the absorption solution into the refrigerant vapor in the high-temperature regenerator 7 and the low-temperature regenerator 6. The refrigerant vapor generated in the high-temperature regenerator 7 is guided to a heat transfer tube 6 a provided in the low-temperature regenerator 6. At this time, cooling is performed by the absorbing solution sprayed around the heat transfer tube 6a from the spraying device 6b disposed in the upper part of the low-temperature regenerator 6. Further, the refrigerant vapor generated outside the heat transfer tube 6a is guided to the condenser 5, and is cooled by cooling water flowing in the heat transfer tube 5a arranged in the condenser 5.
These refrigerants flowing through the heat transfer tubes 5a and 6a are cooled and condensed. The condensed refrigerant is guided to the bottom of the condenser 5 and then to the high-temperature evaporator 3 via the pipe 51.

The refrigerant guided to the high-temperature evaporator 3 is stored in a refrigerant reservoir 3c at the bottom of the high-temperature evaporator 3. The refrigerant pump 31 connected to the refrigerant reservoir 3c via a pipe.
Is sent to the high-temperature evaporator 3. Then, the refrigerant is scattered around the heat transfer tube 3a disposed in the high-temperature evaporator 3 from the refrigerant distribution means 3b disposed in the upper part of the high-temperature evaporator 3. At that time, it is heated and evaporated by the heat transfer medium flowing in the heat transfer tube 3a, and becomes a refrigerant vapor. The generated refrigerant vapor is guided to the high-temperature absorber 4 and is absorbed by the absorbing solution.
The remaining part of the refrigerant accumulated in the refrigerant reservoir 3c of the high-temperature evaporator 3 is guided via the pipe 11 to the refrigerant reservoir 1c provided at the lower part of the low-temperature evaporator 1.

The refrigerant in the low-temperature evaporator 1 contains a small amount of absorbent. The concentration of the refrigerant, which is a dilute solution mixed with the absorbent, is adjusted to a concentration that does not freeze even at 0 ° C. or lower. The diluted solution is supplied to the diluted solution pump 12
Thereby, the refrigerant is sent from the refrigerant reservoir 1c of the low-temperature evaporator 1 to the spraying device 1b provided at the upper part in the low-temperature evaporator 1. Then, it is sprayed from the spraying device 1b around the evaporation heat transfer tube 1a arranged in the low-temperature evaporator 1. At this time, it is heated by the cooling medium flowing in the heat transfer tube 1a.

When the dilute solution is heated, a part of the refrigerant evaporates from the dilute solution to generate refrigerant vapor. The generated refrigerant vapor is led to the low-temperature absorber 2 and is absorbed by the absorbing solution in the low-temperature absorber 2. Refrigerant and absorbent remaining without evaporation
(Lithium bromide) flows down or around the heat transfer tube 1a to the refrigerant reservoir 1c. This flowing refrigerant is
Mixed with the refrigerant from the high-temperature evaporator,
2 to the spraying device 1b.

The cooling medium flowing through the evaporative heat transfer tube 1a is:
Cooled by the heat of evaporation of the refrigerant. Thereafter, the refrigerant is supplied from the absorption refrigerator 200 to the cold heat demand destination via the cold heat medium pipe 13. The cooling medium whose temperature has increased by utilizing the cold heat at the cold heat demand destination is guided again to the low-temperature evaporator 1 and cooled. The cooling medium thus circulates between the absorption refrigerator 200 and a cold heat demand destination (not shown). In the present embodiment, an antifreeze such as brine which does not freeze even when the temperature becomes 0 ° C. or lower is used as the cooling medium.

In the low temperature absorber 2, an absorption heat transfer tube 2a is arranged. Around the absorption heat transfer tube 2a, the absorption solution is sprayed from the spraying device 2b. The sprayed absorption solution is cooled by the heat transfer medium flowing in the absorption heat transfer tube 2a, and absorbs the refrigerant vapor floating in the low-temperature evaporator 2. The heat transfer medium whose temperature has risen due to deprivation of the absorbed heat is evaporated by the high-temperature evaporator 3 by a pipe 32 connecting the absorption heat transfer pipe 2a and the evaporative heat transfer pipe 3a and a heat medium pump 33 interposed in the pipe 32. It is led to the heat tube 3a. The heat transfer medium flowing inside the evaporative heat transfer tube 3a is cooled by the evaporation heat of the refrigerant evaporating around the evaporative heat transfer tube. Then, the process returns to the low-temperature absorber 2 again. The heat transfer medium circulates between the absorption refrigerator 200 and a cold heat demand destination (not shown). In this embodiment, the heat medium is
Inexpensive water with good heat transfer characteristics is used.

The solution having absorbed the refrigerant vapor in the low-temperature absorber 2 is stored in a solution storage 2c provided below the low-temperature absorber. The solution stored in the solution storage 2c is supplied to the solution pump 21
Thereby, it is sent to the low-temperature solution heat exchanger 8, the medium-temperature solution heat exchanger 9, and the drain cooler 71 in this order. Then, each of these devices is sequentially heated. Incidentally, the high temperature regenerator 7 is provided with a float valve 74 for adjusting the flow rate. The solution that has passed through the drain cooler 71 is guided to the float valve 74. After passing through the float valve 74, it is divided into two parts, one of which is guided to the high-temperature solution heat exchanger 10 via the solution pipe 75. The solution heated by the high-temperature solution heat exchanger 10 is led to the high-temperature regenerator 7. Float valve 7
The rest of the solution that has passed through 4 is led to the low-temperature regenerator 6 and is sprayed around a heat transfer tube 6a in the low-temperature regenerator 6 from a spraying device 6b disposed in the upper part of the low-temperature regenerator 6.

The solution guided to the high-temperature regenerator 7 is heated and concentrated by the heat source vapor to generate refrigerant vapor. Here, the heat source steam is supplied from a pipe having a control valve 73 for heat input adjustment.
It is led to the heating side of the high temperature regenerator 7. When the heat source vapor heats the absorbing solution, the heat source vapor condenses to generate drain. The generated drain is guided to the drain cooler 71, and heats the solution guided to the drain cooler 71 through the intermediate temperature solution heat exchanger 9. Thereby, the sensible heat of the drain is recovered.

The absorption solution heated and concentrated in the high-temperature regenerator 7 is supplied to a pipe 76 communicating with the flow rate adjusting section 7a of the high-temperature regenerator 7.
To the high-temperature solution heat exchanger 10. And, when heat exchange with the absorbing solution passed through the float valve 74,
Sensible heat is recovered. The absorption solution led from the high-temperature regenerator 7 via the high-temperature solution heat exchanger 10 joins with the absorption solution from the low-temperature regenerator 6, and is then led to the medium-temperature solution heat exchanger by the solution pump 61.

On the other hand, the absorbing solution guided to the low-temperature regenerator 6 is heated and concentrated by the refrigerant vapor generated in the high-temperature regenerator 7 and guided into the heat transfer tube 6a. At that time, refrigerant vapor is generated. The refrigerant vapor used for heating is condensed in the heat transfer tube 6a to generate drain. The generated drain is led to the condenser 5 communicating with the low-temperature regenerator 6. When draining occurs, the heat of condensation heats the absorbing solution.

The absorption solution, which has been concentrated by heating and condensing in the low-temperature regenerator 6, is supplied from the high-temperature regenerator 7 to the high-temperature solution heat exchanger 1
Merge with the absorption solution passed through 0. And the solution pump 61
After being pressurized and cooled by the medium temperature solution heat exchanger 9, it is guided to the high temperature absorber 4.

In the upper part of the high-temperature absorber 4, a spraying device 4b
Is arranged. The concentrated absorption solution is applied to the spraying device 4b.
From the absorption heat transfer tube 4a arranged in the high-temperature absorber 4. Then, the refrigerant is cooled by the cooling water flowing in the heat transfer tube 4 a and absorbs the refrigerant vapor floating in the high-temperature evaporator 3. A solution reservoir 4c is provided below the high-temperature absorber 4. The solution that has absorbed the refrigerant vapor is stored in the solution reservoir 4c.
It is stored in. A solution pump 41 provided in a pipe connected to the bottom of the solution reservoir 4c sends the solution accumulated in the solution reservoir 4c to the low-temperature solution heat exchanger 8. Then, in the low-temperature solution heat exchanger 8, the heat is exchanged with the absorption solution sent from the low-temperature absorber 2, and the temperature is reduced.

The solution led from the high-temperature absorber 4 is sprayed from the spraying device 2b of the low-temperature absorber 2 around the absorption heat transfer tube 2a. The heat transfer medium cooled in the heat transfer tube 3a of the high-temperature evaporator flows inside the absorption heat transfer tube 2a. The absorbing solution outside the heat transfer tube 2 a is cooled by the heat transfer medium and absorbs the refrigerant vapor floating in the low-temperature evaporator 1.

The absorption solution heated and concentrated in the high-temperature regenerator 7 and the low-temperature regenerator 6 exchanges heat with the solution introduced from the low-temperature absorber 2 in the medium-temperature heat exchanger 9 to lower the temperature. The liquid is guided to the low-temperature solution heat exchanger 8 via the high-temperature absorber bypass pipe 45, and the remainder is guided to the spraying means 4 b of the high-temperature absorber 4 via the pipe 91. The bypass pipe 45 has a control valve 4 for adjusting the flow rate of the solution flowing in the bypass pipe 45.
5a is provided. By providing the bypass pipe 45, the concentration of the absorbing solution flowing into the low temperature absorber 2 becomes higher than the concentration of the solution flowing out of the high temperature absorber 4.

In order to control the flow rate and temperature of the refrigerant and the solution flowing in the absorption refrigerator 200 configured as described above,
A control device 100 is provided. The control device 100 includes a temperature sensor 14 for detecting a cooling medium outlet temperature, a temperature sensor 34 for detecting a heat transfer medium temperature, a temperature sensor 35 for detecting a high temperature evaporator refrigerant temperature, and a temperature sensor 44 for detecting a cooling water inlet temperature. Are input. The control device controls the solution pumps 21 and 4 based on these signals.
1, 61, the heat medium pump 33 and the control valve 45a are controlled.

More specifically, when the temperature of the refrigerant or the heat transfer medium in the high-temperature evaporator 3 decreases, that is, at least one of the high-temperature evaporator refrigerant temperature, the heat medium temperature, and the cooling water inlet temperature exceeds the respective set values. When the pressure also decreases, the control device 100 opens the control valve 45a to increase the bypass flow rate of the high temperature absorber. Conversely, each of the temperature sensors 34, 35,
If all the temperatures detected by 44 are equal to or higher than the respective set values, the control valve 45a is closed.

Cooling water is supplied to the absorption refrigerator 200 through a cooling water pipe 42. A cooling water bypass pipe 42a is provided to bypass the cooling water pipe 42.
The cooling water bypass pipe 42a has a control valve 42b. The control valve 42b is connected to the control device 100.

The control device 100 controls the control valve 4 during normal operation.
Close 2b. When the temperatures of the refrigerant and the heat transfer medium of the high-temperature evaporator 3 decrease, that is, when at least one of the refrigerant temperature, the heat transfer medium temperature, and the cooling water inlet temperature of the high-temperature evaporator falls below the respective set values, the control valve 42b is turned off. open. Thereby, the bypass flow rate of the cooling water increases, and the flow rate of the cooling water supplied to the absorption refrigerator decreases.

In this embodiment, since the bypass pipe 45 for guiding the solution to the low-temperature absorber by bypassing the high-temperature absorber is provided, the concentration of the absorbing solution flowing into the low-temperature absorber 2 increases. As the absorption solution concentration increases, the absorption temperature also increases, and the temperature of the heat transfer medium flowing in the absorption heat transfer tube increases. Along with this, the evaporation temperature of the high-temperature evaporator 3 for cooling the heat transfer medium rises, and the refrigerant temperature of the high-temperature evaporator 3 also rises, so that freezing of the refrigerant can be prevented. Also, a high-temperature evaporator 3 and a low-temperature absorber 2
Even if water is used as the heat transfer medium that circulates, freezing of the water can be prevented. Since water does not freeze, water can be used as a heat transfer medium, so that there is no need to use an antifreeze such as brine and the cost is low. Since water has good heat transfer characteristics, the heat transfer area can be reduced, and the size and cost of the device can be reduced.

In this embodiment, the refrigerant temperature sensor 35
The controller controls the flow rate of the high-temperature absorber bypass pipe 45 based on temperature information detected by at least one of the heat medium temperature sensor 34 and the cooling water temperature sensor 44. Therefore, during normal operation in which there is no possibility of freezing of the refrigerant and the heat transfer medium, the flow rate of the high-temperature absorber bypass pipe 45 can be made zero, and the solution flow rate supplied to the absorption heat transfer pipe in the high-temperature absorber can be maximized. Can be. As a result, the heat transfer performance of the high-temperature absorber can be improved. During normal operation, high-performance operation with a bypass flow rate of zero is performed, and when the temperature of the cooling water drops, the control valve 45 is used to prevent the refrigerant from freezing.
By opening a and performing the anti-freezing operation, the operable range can be expanded.

The flow rate of the cooling water flowing through the bypass pipe 42a is controlled based on the temperature detected by at least one of the refrigerant temperature sensor 35, the heat transfer medium temperature sensor 34, and the cooling water temperature sensor 44. This allows the entire amount of cooling water discharged from the cooling water pump 43 to be supplied to the absorption refrigerator during normal operation, and reduces the flow rate of the cooling water supplied to the absorption refrigerator when there is a risk of refrigerant freezing. become. As a result, the refrigerant and the heat transfer medium of the high-temperature evaporator 3 do not freeze even when the temperature of the cooling water becomes low, and the absorption refrigerator can be operated over a wide temperature range of the cooling water.

FIG. 2 shows another embodiment of the present invention. In this embodiment, the concentration of the solution flowing into the low temperature absorber is higher than the concentration of the solution flowing out of the high temperature absorber. Therefore, in this embodiment, unlike the embodiment shown in FIG. 1, the concentrated solution heated and concentrated by the high-temperature regenerator and the low-temperature regenerator is led to the medium-temperature solution heat exchanger 9 and then to the low-temperature absorber. This is because the water flows separately to the piping system leading to the high-temperature absorber. That is, the high-temperature absorber 4 has a flow control valve 45.
A pipe 91 having a is connected thereto, and a pipe 92 branched from the pipe 91 and having a low-temperature solution heat exchanger 8 interposed is connected to the low-temperature absorber 2. Other configurations of the absorption refrigerator are the same as those of the absorption refrigerator shown in FIG.

In this embodiment, as compared with the embodiment shown in FIG. 1, the concentration of the solution flowing into the low temperature absorber 2 is further increased, and the margin for freezing the refrigerant is further increased. Further, although the flow rate of the cooling water supplied to the absorption refrigerator is controlled by controlling the flow rate of the bypass pipe 42b, the cooling water pump 43 may be inverter-controlled. In that case, the power consumption of the cooling water pump 43 can also be reduced.

Further, in each of the above embodiments, the cooling capacity of the high-temperature absorber 4 is reduced by controlling the flow rate of the cooling water in order to prevent the refrigerant and the heat transfer medium from freezing. Instead, the temperature of the cooling water may be controlled. That is,
When the temperature of the refrigerant in the high-temperature evaporator 3 or the temperature of the heat transfer medium drops below a predetermined value, the temperature of the cooling water is raised. Thus, the absorption capacity of the solution in the high-temperature absorber 4 for absorbing the refrigerant is reduced, and a decrease in the evaporation temperature is prevented. As a result, freezing of the refrigerant and the heat transfer medium can be prevented.

The flow rate of the absorbing solution supplied to the high-temperature absorber 4 may be reduced by inverter-controlling the solution pump 61. If this inverter control of the solution pump is combined with cooling water flow rate control and temperature control, a great effect can be obtained in preventing freezing.

Further, in each of the above embodiments, the control valve 45a is provided in the high-temperature absorber bypass pipe 45, but a fixed throttle means may be provided instead of this control valve. With this configuration, the control system is simplified, and freezing can be prevented by providing the throttle means. The fixed throttle means may be a pipe having a sufficiently small inner diameter. Further, a manual flow control valve may be used as the fixed throttle means.

In this case, there is an advantage that the bypass flow rate can be changed according to a change in the characteristics of the device due to aging or the like.

Further, in each of the above embodiments, a double effect absorption refrigerator having two regenerators has been described. However, a single effect absorption refrigerator having one regenerator or a triple effect absorption refrigerator having three regenerators is described. Needless to say, the present invention can be applied to a machine.

[0041]

As described above, according to the present invention, in the absorption refrigerator, the solution flowing out of the medium-temperature solution heat exchanger can be distributed to the low-temperature absorber and the high-temperature absorber. Of the heat transfer medium circulating between the high temperature evaporator and the low temperature absorber can be prevented. As a result, stable refrigeration capacity and cooling medium temperature can be obtained throughout the year. Further, water can be used as a cooling medium.

[Brief description of the drawings]

FIG. 1 is a system diagram of an embodiment of an absorption refrigerator according to the present invention.

FIG. 2 is a system diagram of another embodiment of the absorption refrigerator according to the present invention.

[Explanation of symbols]

1: Low temperature evaporator, 2: Low temperature absorber, 3: High temperature evaporator, 4
... High temperature absorber, 5 ... Condenser, 6 ... Low temperature regenerator, 7 ... High temperature regenerator, 8 ... Low temperature solution heat exchanger, 9 ... Medium temperature solution heat exchanger, 10 ... High temperature solution heat exchanger, 11 ... Refrigerant piping , 11a
... refrigerant flow control valve, 12 ... dilute solution pump, 13 ... cold heating medium pipe, 14 ... cold heating medium temperature sensor, 21 ... solution pump, 31 ... refrigerant pump, 32 ... heat transfer medium pipe, 33 ... heat transfer medium pump, 34 ... heat transfer medium temperature sensor, 35 ... refrigerant temperature sensor, 41 ... solution pump, 42 ... cooling water piping, 4
2a cooling water bypass pipe, 42b control valve, 43 cooling water pump, 44 cooling water temperature sensor, 45 high temperature absorber bypass pipe, 45a control valve, 51 refrigerant pipe, 6
DESCRIPTION OF SYMBOLS 1 ... Solution pump, 71 ... Drain cooler, 72 ... Heat source steam piping, 73 ... Steam control valve, 74 ... Float valve, 7
5, 76, 91 ... solution piping.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomohisa Ouchi 603, Kandamachi, Tsuchiura-shi, Ibaraki F-term in Industrial Machinery Systems Division, Hitachi Ltd. 3L093 BB12 BB13 BB37 CC03 DD08 EE09 GG02 HH15 JJ02 KK03 LL03 MM07

Claims (8)

[Claims] 1. An absorption refrigerator comprising a regenerator, a condenser, a high-temperature evaporator, a low-temperature evaporator, a high-temperature absorber and a low-temperature absorber, wherein the concentrated solution heated and condensed by the regenerator is cooled by the low-temperature absorber. And a heat exchanger that absorbs the refrigerant with the high-temperature absorber and exchanges heat with the diluted solution that has been diluted. The first stream that guides the concentrated solution cooled by exchanging heat with the heat exchanger to the high-temperature absorber. An absorption refrigerator comprising a passage and a second passage leading to the low-temperature absorber. 2. The absorption refrigerator according to claim 1, wherein a flow control means is provided in said second flow path. 3. A high-temperature evaporator having a refrigerant temperature detecting means for detecting a refrigerant temperature, and a control device for controlling the flow rate control means based on the refrigerant temperature detected by the refrigerant temperature detecting means. The absorption refrigerator according to claim 2, characterized in that: 4. An absorption refrigerator comprising a regenerator, a condenser, a high-temperature evaporator, a low-temperature evaporator, a high-temperature absorber through which cooling water flows, and a low-temperature absorber. It is characterized by comprising a refrigerant temperature detecting means for detecting, and a control device for controlling at least one of the temperature and the flow rate of the cooling water flowing through the high-temperature absorber based on the refrigerant temperature detected by the refrigerant detecting means. And absorption refrigerator. 5. An absorption refrigerator comprising a regenerator, a condenser, a high-temperature evaporator, a low-temperature evaporator, a high-temperature absorber through which cooling water flows, and a low-temperature absorber. The heat transfer medium is circulated, and a heat transfer medium temperature detecting means for detecting the temperature of the heat transfer medium is provided in the circulation path. A control device for controlling at least one of the temperature and the flow rate of the cooling water flowing through the absorber. 6. An absorption refrigerator comprising a high-temperature regenerator, a low-temperature regenerator, a condenser, a high-temperature evaporator, a low-temperature evaporator, a high-temperature absorber through which cooling water flows, and a low-temperature absorber. A circulation path through which the heat transfer medium circulates between the low-temperature absorbers; a heat transfer medium temperature detection means for detecting the temperature of the heat transfer medium provided in the circulation path; a cooling water inlet of the high-temperature absorber and the high-temperature absorber; A bypass pipe connecting a position downstream of the outflow portion where the cooling water flows out from the absorber to the outside, a flow control means provided in the bypass pipe, and a heat transfer medium temperature detected by the temperature detection means. A control device for controlling the flow rate of the cooling water flowing through the high-temperature absorber by using the flow rate control means. 7. An absorption refrigerator comprising a high-temperature absorber, a low-temperature absorber, a high-temperature evaporator, and a low-temperature evaporator using water as a refrigerant and lithium bromide as an absorbent, and flows into the low-temperature absorber. An absorption refrigerator comprising a control means for increasing the concentration of the solution higher than the concentration of the solution flowing out of the high-temperature absorber. 8. The absorption refrigerator according to claim 1, wherein said refrigerant is water and said solution is an aqueous solution of lithium bromide.