JP3143251B2 - Absorption refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption type refrigerator such as an absorption refrigerator or an absorption chiller / heater which performs a heat exchange operation by a required heat pump action using an absorption liquid in which a heat absorber is mixed with a vaporizable refrigerant. It relates to a refrigerator.

[0002]

2. Description of the Related Art As an apparatus of this type, for example, an absorption refrigerator using an absorption liquid such as an aqueous solution of lithium bromide in which lithium bromide is used as an absorbent and water is used as a refrigerant is known. Is configured as the absorption chiller / heater 100 of the first embodiment.

In FIG. 5, a thick solid line indicates a liquid conduit for a refrigerant liquid, an absorbing liquid and cooling water, and a double line indicates a vapor line for a refrigerant vapor. 1
Low concentration absorbing solution stored at the bottom of
A description will be made with reference to FIG.

[0004] The dilute solution 2a enters the high temperature regenerator 5 via the pipe 3 by the pump P1. Since the high temperature regenerator 5 is heated from below by a heater 6 such as a burner, the diluted liquid 2a
The refrigerant contained therein evaporates and separates into a high-temperature, medium-concentration absorbent, that is, the intermediate liquid 2b and the refrigerant vapor 7a.

[0005] The high-temperature intermediate liquid 2 b enters a high-temperature-side heat exchanger 9 via a pipe 8. In the heat exchanger 9, the high-temperature intermediate liquid 2
b gives heat to the dilute solution 2a passing through the pipe 3 to radiate heat, and after the temperature drops, enters the low-temperature regenerator 11 via the pipe 10.

In the low-temperature regenerator 11, the refrigerant vapor 7 a is sent to the radiating pipe 11 A in the low-temperature regenerator 11 for heating the intermediate liquid 2 b via the pipe 21 and is heated.
The refrigerant contained in b evaporates and separates into a high-temperature, high-concentration absorbent, that is, a concentrated liquid 2c, and refrigerant vapor 7b.

The high-temperature concentrated liquid 2 c enters the low-temperature heat exchanger 13 via the pipe 12. In the heat exchanger 13, the high-temperature concentrated liquid 2 c gives heat to the diluted liquid 2 a passing through the pipe 3, radiates heat, and after reaching a medium temperature, passes through the pipe 14 and spreads the sprayer 1 in the absorber 1.
A, and sprays from many holes of the sprayer 1A.

The sprayed concentrated liquid 2c is cooled by cooling water 32a flowing through a cooling pipe 1B in the absorber 1. When flowing down the outside of the cooling pipe 1B, the concentrated liquid 2c absorbs and dilutes the refrigerant vapor 7c entering from the adjacent evaporator 26, returns to the low-temperature diluted liquid 2a, and completes the absorption liquid. The absorption liquid circulation is repeated.

Next, the refrigerant circulation system will be described with the refrigerant vapor 7C entering the absorber 1 as a starting point. The refrigerant vapor 7c is
As described in the above-described absorbent circulation system, the concentrated liquid 2c dispersed from the sprayer 1A in the absorber 1 absorbs the diluted liquid 2a.
Into the refrigerant vapor 7a in the high-temperature regenerator 5.

The refrigerant vapor 7a enters the radiating pipe 11A of the low-temperature regenerator 11 via the pipe 21, gives heat to the intermediate liquid 2b to radiate heat, condenses into the refrigerant liquid 24a, and then changes to the pipe 22.
And enters the bottom of the condenser 23.

The condenser 23 is provided with a refrigerant vapor 7b which enters through a number of passages 11B between the adjacent low-temperature regenerators 11b.
To the cooling water 32a passing through the cooling pipe 23A in the condenser 23.
And condenses the refrigerant vapor 7b to produce a low-temperature refrigerant liquid 24a.
To The refrigerant liquid 24a passes through a pipe 25 and passes through an evaporator 26.
, And accumulates in the lower part of the evaporator 26 to become the refrigerant liquid 24b.

The pump P2 supplies the refrigerant liquid 24b to the pipe 28
Is sent to the sprayer 26A, and the spraying from a number of holes of the sprayer 26A is repeated. Sprayed refrigerant liquid 24b
Is a fluid to be heated which passes through a heat exchange pipe 26B in the evaporator 26,
That is, the cold / warm water 35a is cooled. During this cooling, the refrigerant liquid 24b absorbs heat from the cold / warm water 35a and evaporates to become refrigerant vapor 7c.
Then, the refrigerant returns to the absorber 1 through a large number of passages 26C, and the circulation of the refrigerant is completed.

As described above, by the double regeneration operation of the high-temperature regenerator 5 and the low-temperature regenerator 11, the heat exchange pipe 2 in the evaporator 26 is circulated while circulating the absorbing liquid and the refrigerant, that is, the heat operating fluid.
6B, that is, the heat-operated fluid supplied from the pipe 36, that is, the cooling / rewarming water 35a, is cooled by the heat exchange pipe, and the chilled water 35b is cooled from the pipe 37 to the cooling target device such as an indoor cooling device (FIG. (Not shown) as a heat-receiving operation fluid for cooling is referred to as a double-effect cooling operation, and is also referred to as a cooling operation because it is mainly used for cooling.

On the other hand, the refrigerant vapor 7a evaporated in the high-temperature regenerator 5 and the high-temperature intermediate liquid 2b to be put in the high-temperature heat exchanger 9 are provided in the pipelines 41 and 42 which are bypassed to the evaporator 26. The open / close valves V1 and V2 are opened to return directly to the evaporator 26 and the absorber 1, and the refrigerant liquid 24b to be sprayed from the sprayer 26A is bypassed between the pipe 28 and the pipe 3. The on-off valve V3 provided in the passage 43 is opened to mix the refrigerant liquid 24b into the absorbing liquid 2a, and the operation of only the high-temperature regenerator 5 without using the low-temperature regenerator 11 allows the absorption liquid circulation and the refrigerant circulation to be performed. While performing, the heat exchange pipe 26B in the evaporator 26, that is, the heat exchange pipe, that is, the heat-operated fluid provided from the pipe 36, that is, the cold / warm water 35a is heated, and the hot water 35b is supplied from the pipe 37. Heating equipment (not shown) such as indoor heating equipment The operation given as use the heat operation fluid, say warming operation (boiler operation), mainly due to the use for heating, and also said heating operation.

During the heating operation, the cooling of the absorber 1 and the condenser 23 is not required. Therefore, the operation of the pump P3 is stopped to stop the supply of the cooling water 32a from the pipeline 31. . Further, during the cooling operation and the heating operation, the cooling / heating water 35b is circulated to the cooling load or the heating load to be cooled or heated by the pump P4, and is returned as the cooling / heating return water 35a.

The control section 50 is a control section for controlling and processing the above operation in the absorption chiller / heater 100. As described above, the control section 50 opens and closes the on-off valves V1, V2, V3 and the pumps P1, P2.
2. By controlling the operation / stop of P3, the operation is switched between the cooling operation and the heating operation, and during each operation, the cooling / hot water 35b given to the device to be cooled or the device to be heated is heated to a predetermined temperature. In order to maintain the control signal, a required operation signal given from a setting operation device (not shown) or the like,
The temperature detectors S1 and S2 for detecting the temperature of the warm-back water 35a and the cold / hot water 35b, and the respective detection signals provided from the temperature detectors S3 and S4 for detecting the temperatures of the cooling water 32a and the cool-back water 32b. On the basis of this, by controlling the heating regulator 6A for adjusting the heating amount of the heater 6, etc., a steady temperature control operation is performed. For this reason, the equipment to be controlled is of an electric type.
In some cases, the administrator manually opens and closes the on-off valves V1, V2, and V3 to switch between the cooling operation and the heating operation.

In the absorption chiller / heater 100 configured to circulate the absorption liquids 2a, 2b, and 2c, when the double-effect operation is stopped, a portion of the absorption liquid that has become the concentrated liquid 2d, that is, If the absorbent between the pipe 12, the heat exchanger 13 and the pipe 14 is left in a high-concentration state, the components of the absorbent crystallize and precipitate, and the pipe is blocked, causing a failure. Before stopping completely,
In a state where the heating controller 6A is closed and the heating by the heater 6 is stopped, the on-off valve V3 is opened (while the on-off valve V3 is closed when the opening and closing valve V3 is manually operated) while the refrigerant liquid 24b is mixed with the diluted liquid 2a. P1 is operated to circulate the absorbing solution, and after performing a dilution operation for diluting the concentration of the entire absorbing solution, particularly the concentration of the portion of concentration 2a, the operation is stopped.
The configuration of the absorption chiller 100 provided with this kind of dilution operation is described in “Absorptive chiller / heater / absorption chiller C series catalog '90” issued by the present applicant Sanyo Electric Co., Ltd. in July 1990.
-7 ", published by Ohmsha in February 1989," Practical knowledge of air conditioning equipment "or Japanese Patent Application Laid-Open No. 57-202465.

Further, as shown in FIG. 1, for example, a high-temperature regenerator 5 in the above absorption refrigerator is provided with a heating tank 5A for heating only the diluted liquid 2a, and a refrigerant vapor from the heated diluted liquid 2a. 7a and a separation tank 5C for separation into an intermediate liquid 2b, and a pipe 5B between the heating tank 5A and the separation tank 5C.
The construction of the absorption refrigerator 100 provided with
0940 and the like.

[0019]

In the above-described absorption chiller / heater 100, when the operation is switched from the cooling operation to the heating operation or when the cooling operation is stopped, troubles such as crystallization of the absorbing solution may occur. In order to prevent this, it is necessary to perform a dilution operation to dilute the absorbent, and during this dilution operation, the cooling capacity of the absorbent, refrigerant liquid, refrigerant vapor, etc. during the cooling operation performed earlier remains, so this Due to the cooling capacity, the operation fluid to be heated in the heat exchange tube 26A in the evaporator 26, that is, the cold / hot water 35a is supercooled, and there is a disadvantage that freezing damage is caused. Further, if the dilution operation time is long, there is a disadvantage that power consumption of the pump increases.

Also, during a normal cooling operation, if there is a sudden change such as a sudden stop of the operation on the cooling load side supplying the heat-operated fluid, that is, the cold / hot water 35a, the cooling operation is stopped. / There is an inconvenience that the hot water 35a is supercooled, causing freezing damage.

In order to prevent such overcooling, measures have been taken, such as performing time-based control for sequentially stopping the operation of each load in accordance with the operating conditions on the load side predicted in advance. However, such means has a disadvantage that when there is a change in the load side that is not expected, freezing damage due to the above-mentioned supercooling is caused.

For this reason, there is a problem that it is desired to provide an apparatus by means that does not cause such inconvenience.

[0023]

According to the present invention, there is provided an absorbent circulating system for circulating an absorbent obtained by mixing the above-mentioned absorbent into a refrigerant through heat exchange equipment such as a high-temperature regenerator and an absorber.
The refrigerant vapor and the refrigerant liquid from which the above-mentioned absorption liquid has been separated are condensed into a condenser
In an absorption refrigerator which cools a working fluid to be heated passing through a heat exchange pipe in an evaporator by a refrigerant circulating system circulating through heat exchange devices such as an evaporator, the absorption chiller is attached to the high temperature regenerator. A freezing prevention heat exchange means for providing a heating heat exchanger for preventing freezing of the heated operating fluid in the pipeline, and the heated operating fluid in the pipeline attached to the heat exchange pipe freezes. A first configuration in which a heating means is provided for heating the heat-operated fluid to the heating heat exchanger when the temperature becomes equal to or lower than a temperature value predicted as a temperature immediately before the heating, and as described above. Liquid circulation system that circulates the absorbent mixed with the absorbent into the refrigerant through heat exchangers such as high-temperature regenerators and absorbers, and condenser / evaporates the refrigerant vapor and refrigerant liquid separated from the above absorbent. A refrigerant circulation system that circulates through heat exchangers When the operation fluid to be heated passing through the heat exchange pipe in the vessel is switched between a heating operation for heating and a cooling operation for cooling, and when the cooling operation is stopped or the switching operation from the cooling operation is performed, In the absorption refrigerator in which the dilution operation for diluting the concentration of the absorbent in the absorption liquid is performed, the pipe line attached to the high-temperature regenerator is heated to prevent freezing of the fluid to be heated. A second configuration including a freezing prevention heat exchange means for providing a heat exchanger for heating, and a heating means for supplying a working fluid to be heated to the heat exchanger for heating to heat the heat exchanger during the dilution operation. The present invention has been made to solve the above problems.

[0024]

In the first configuration, during the cooling operation, since the high-temperature refrigerant vapor or the high-temperature absorbing liquid flows through the pipeline attached to the high-temperature regenerator, the heating heat exchanger is always in a heated state. When the temperature of the heated fluid falls below a temperature value predicted as a temperature immediately before the freezing of the fluid to be frozen, for example, 3 ° C. or less, the fluid to be heated is supplied to the heat exchanger for heating. If this is the case, the fluid to be heated can be immediately heated, and it is possible to prevent supercooling, so that it always acts to prevent freezing damage.

In the second configuration, during the dilution operation,
During the cooling operation performed earlier, high-temperature refrigerant vapor or high-temperature absorption liquid flows through the pipes attached to the high-temperature regenerator, so that sufficient residual heat still remains. The vessel is warm. For this reason, the heat-operated fluid can be heated, and it is possible to prevent supercooling, so that freezing damage is prevented beforehand.

[0026]

An embodiment will be described below with reference to FIGS.
In these figures, the portions denoted by the same reference numerals as those in FIG. 5 are portions having the same functions as the portions denoted by the same reference numerals described with reference to FIG.

Since FIGS. 1 and 2 show the construction of the absorption refrigerator, the locations of the cold / hot water 35a and 35b in FIG. 5 are the cold water 35a and 35b. In the case of an absorption chiller / heater that switches between cooling and heating, a portion corresponding to the pipeline 41 and the on-off valve V1 bypassing between the separator 5C and the evaporator 26 in FIG. Must be provided also in the configurations of FIGS.

[First Structure] The first structure shown in FIG. 1 is different from the first structure shown in FIG.
a, 2b, 2c, and 2d are circulated through heat exchangers such as the high-temperature regenerator 5 and the absorber 1, and the refrigerant vapors 7a and 7b and the refrigerant liquids 24a and 24b are condensed into condensers 23 and 24.
A refrigerant circulation system that circulates through heat exchange devices such as the evaporator 26, and an absorption refrigeration system that cools the heat-operated fluid, that is, the chilled water 35a / 35b, passing through the heat exchange pipe 26B in the evaporator 26. High-temperature regenerator 5
A freezing prevention heat exchange means for providing a heating heat exchanger 64 for preventing freezing of the fluid to be heated, in a pipe 5B attached to the pipe, and a pipe 37 in a pipe 37 attached to the heat exchange pipe 26B. When the temperature of the heat-operated fluid becomes equal to or lower than a temperature value predicted as a temperature immediately before the freezing of the heat-operated fluid, for example, 3 ° C. or lower, the heat-operated fluid is supplied to the heat exchanger 64 for heating to heat. Means are provided.

Hereinafter, a specific description will be given.
As described above, the portion of the pipe 63 is constituted by a heating tank 5A, a pipe 5B, and a separation tank 5C instead of the high-temperature regenerator 5 in FIG. 5, and a pipe 63 bypassing the middle of the pipe 5B.
Is provided with a heat exchanger 64, and during the cooling operation, the diluted liquid 2a passing through the pipe 64 is controlled by the control operation of the control unit 50.
Is always hot.

In the portion of the pipe 28 attached to the evaporator 26, a bubble pump 62 is provided instead of the pump P 2 in FIG. 5, and the relatively high-temperature refrigerant liquid 24 a in the pipe 22 is supplied to the radiating pipe 61. After passing through, the refrigerant liquid 2 is supplied to the condenser 23 and the refrigerant liquid 2
4b is circulated.

Further, a bypass by a pipe 65 and a pipe 66 is provided across the pipe 37 and the pipe 36 attached to the heat exchange pipe 26B, and a connecting point between the pipe 37 and the pipe 65 is provided. A flow path switching valve provided by a three-way valve V4 is provided. By the switching operation of the three-way valve V4, the operation target fluid to be heated, that is,
The cold waters 35a and 35b are passed through the pipes 65 and 66 so that they can be heated by the heat exchanger 64.

During the cooling operation state by the control processing operation of the control unit 50, the control processing function provided in the control unit 50, for example, the program stored in the microcomputer, causes the temperature detector S2 to operate. Detected temperature value T
1 is compared with a predetermined reference temperature value T0, and when the detected temperature value T1 becomes equal to or lower than the reference temperature value T0, a control process is performed so as to output a control signal for opening the three-way valve V4 to the pipe line 65 side. are doing. The reference temperature value T0 is a temperature value predicted as a temperature immediately before the fluid to be heated, that is, the cold water 35a / 35b starts freezing, for example, a value of 3 ° C., and this value is stored in the memory of the microcomputer. Is stored in advance.

By this control processing, the cold water 35a
b due to a sudden change in the load condition on the load side with respect to b.
When the temperature a.35b becomes equal to or lower than the temperature value predicted as the temperature immediately before the freezing, the three-way valve V4 operates and the cold water 35
The flow paths a and 35b are switched to the pipe lines 65 and 66, and the cold water 35a and 35b are heated by the heat exchanger 64 for heating.
Since 5a and 35b are provided, the operation is performed to suppress supercooling.

FIG. 2 shows an essential part of the first configuration shown in FIG. 1 as a concretely similar configuration. In FIG. 2, the same reference numerals as those shown in FIG. Are portions having the same functions as the same reference numerals in FIG.

[Second Configuration] The second configuration is as follows.
Each functional part is the same as in FIG. 1 and FIG.
The control target in the control process of FIG. 5 is configured to control the three-way valve V4 in the operation during the dilution operation, and as shown in FIG. 5, the absorbent 2a in which the absorbent is mixed in the refrigerant.
An absorbent circulating system for circulating 2b, 2c, 2d through heat exchangers such as a high-temperature regenerator 5 and an absorber 1, and a condenser 23 which converts the refrigerant vapors 7a, 7b and the refrigerant liquids 24a, 24b by the refrigerant into a condenser 23. A refrigerant circulation system that circulates through heat exchange devices such as the evaporator 26, and a cooling system that passes cooling water 32a to required heat exchange devices such as the absorber 1 and the condenser 23 are provided. In addition to performing a cooling operation for cooling the heated working fluid passing through the heat exchange pipe 26B, that is, the chilled water 35a / 35b, a dilution operation for diluting the concentration of the absorbent in the absorbing solution when the cooling operation is stopped. In the absorption chiller 100 that is to be performed, a freezing-preventing heat exchange unit is provided with a heating heat exchanger 64 for preventing freezing of the working fluid to be heated in the pipe 5B attached to the high-temperature regenerator 5. ,
By the control processing operation of the control unit 50, a heating means for providing the operation fluid to be heated, that is, the cold water 35a / 35b to the heat exchanger 64 for heating and for heating is provided during the above-mentioned dilution operation. Has become.

1 and 2 are exactly the same as those in the first configuration, and are put into the dilution operation state by the control processing operation of the control unit 50. During this period, the heating controller 6A is closed and the heating operation of the heater 6 is stopped by the control processing function provided in the control unit 50, for example, the program stored in the microcomputer, as described with reference to FIG. In addition, in the second configuration, the on-off valve V4 by the three-way valve is operated to perform control processing so as to switch the flow path of the fluid to be heated, that is, the cold water 35a / 35b, to the bypass by the pipes 65/66. ing.

In this dilution operation state, the heating operation by the heater 6 is stopped, but the line 5 belonging to the high-temperature regenerator 5
In B, since the preheating by the heating operation at the time of the cooling operation performed previously remains, the cold waters 35a and 35b are heated by the heating heat exchanger 64 for a while. For this reason,
Heated cold water 35a / 35b is provided in the heat exchange pipe 26B.
Is given, so that the operation is performed so as to suppress the supercooling. Further, the heat exchanger 64 uses the absorbing liquid 2a.
Is cooled, the generation of the refrigerant vapor 7a is suppressed and the concentration becomes low, so that the dilution operation time can be shortened.

[Modified Embodiment] The present invention can be implemented with the following modifications.

(1) In the first configuration and the second configuration, the high-temperature regenerator 5 is configured similarly to the high-temperature regenerator 5 in FIG.

(2) In the first configuration and the second configuration, the three-way valve V4 operates the refrigerant liquid 24 in the condenser 23 for a predetermined time from the start of the dilution operation, for example, at the start of the dilution operation.
The switching is performed for a time proportional to the amount of “a”.

(3) In the first configuration and the second configuration, the three-way valve V4 is opened and the pump P3 is stopped at the same time.

(4) In the first configuration and the second configuration, the portion of the bubble pump 62 is modified similarly to the portion by the pump P2 in FIG.

(5) In the first and second configurations, the three-way valve V4 is moved to the pipe 36 side.

(6) As shown in FIG. 3, specifically, as shown in FIG. 3, specifically, as shown in FIG. 4, the three-way valve V4 switches the flow path of the pump P4 → the three-way valve V4 → the pipe 66 → the heat exchanger 64 → Conduit 65
→ The evaporator 26 is configured so that the evaporator 26 can be directly heated by the fluid to be heated whose temperature has been increased by the heat exchanger 64 so that the evaporator 26 becomes the flow path of the pipe 36b.

(7) The first configuration and the second configuration, or
In the configurations of (5) and (6) above, in place of the three-way valve V4, a passage type on-off valve provided in the line 36 or the line 37 and a passage-type on-off valve provided in the line 65 or the line 66 Are provided to control the opening and closing of these on-off valves simultaneously.

(8) The first configuration and the second configuration, or
In the above configurations (1) to (6), the heat exchanger 64 for heating is moved to the pipe 5B itself, or an arbitrary one attached to the high-temperature regenerator 5 such as the pipe 8 and the pipe 21. It is relocated to the pipeline and configured.

[0047]

According to the present invention, as described above, the first
In the cooling operation, when the temperature of the fluid to be heated becomes lower than a temperature value predicted as a temperature immediately before the freezing of the fluid to be frozen due to a sudden change in the load, for example, 3 ° C. or less, the heating operation is performed. Since the fluid is given to the heat exchanger for heating and heated, supercooling can be prevented, so that freezing damage can always be prevented.

Further, in the second configuration, during the dilution operation, the refrigerant vapor is discharged by the heating heat exchanger having residual heat remaining in the pipe attached to the high-temperature regenerator during the cooling operation performed earlier. Since the generation of heat can be suppressed, heating the fluid to be heated can be prevented from overcooling, freezing damage can be prevented beforehand,
In addition, since the concentration is reduced by cooling the high-temperature absorbent, the dilution operation time is shortened.

[Brief description of the drawings]

1 to 4 show an embodiment of the present invention, and FIG. 5 shows a prior art. The contents of each drawing are as follows.

FIG. 1 is a block configuration diagram

FIG. 2 is a specific configuration diagram of a main part.

FIG. 3 is a modified configuration diagram of a main part.

FIG. 4 is a diagram showing a specific modified configuration of a main part.

FIG. 5 is a block diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Absorber 1A Sprayer 1B Cooling pipe 2a Rare liquid 2b Intermediate liquid 2c Concentrated liquid 3 Pipeline 5 High temperature regenerator 5A Heating tank 5B Pipeline 5C Separation tank 6 Heater 6A Heating regulator 7a Refrigerant vapor 7b Refrigerant vapor 7c Refrigerant vapor 8 Pipeline 9 Heat exchanger 10 Pipeline 11 Low temperature regenerator 11A Heat radiator pipe 11B Passage 12 Pipeline 13 Heat exchanger 14 Pipeline 21 Pipeline 22 Pipeline 23 Condenser 23A Cooling pipe 24a Refrigerant liquid 24b Refrigerant liquid 25 Pipeline 26 Evaporator 26A Sprayer 26B Cooling pipe 28 Pipeline 31 Pipeline 32a Cooling water 32b Cooling return water 33 Pipeline 34 Pipeline 35a Cold / hot return water 35b Cold / hot water 36 Pipeline 37 Pipeline 41 Pipeline 42 Pipeline 43 Pipeline 50 Control unit 61 Radiator tube 62 Auxiliary evaporator 63 Pipeline 64 Heat exchanger 100 Absorption refrigerator P1 Pump P2 Pump P3 Pump S1 Temperature Detector S2 Temperature detector S3 Temperature detector S4 Temperature detector V1 Open / close valve V2 Open / close valve V3 Open / close valve V4 Three-way valve

Claims (2)

(57) [Claims] An absorbent circulating system for circulating an absorbent mixed with an absorbent into a refrigerant through heat exchangers such as a high-temperature regenerator and an absorber, and condensing a refrigerant vapor and a refrigerant liquid separated from the absorbent. An absorption chiller configured to cool a working fluid to be heated passing through a heat exchange pipe in the evaporator by a refrigerant circulating system circulating through heat exchangers such as an evaporator and an evaporator. An antifreezing heat exchange means for providing a heating heat exchanger for preventing the freezing of the heated working fluid in a pipe attached to the vessel, and the heat receiving in the pipe attached to the heat exchange pipe. And a heating means for supplying the heat operation fluid to the heating heat exchanger to heat the operation fluid when the temperature of the operation fluid becomes equal to or lower than a temperature value predicted as a temperature immediately before the freezing of the operation fluid. Absorption refrigerator. 2. An absorbent circulating system for circulating an absorbent mixed with an absorbent into a refrigerant through heat exchangers such as a high-temperature regenerator and an absorber, and condensing a refrigerant vapor and a refrigerant liquid separated from the absorbent. A refrigerant circulating system that circulates through heat exchangers such as an evaporator and an evaporator, and performs a heating operation for heating a fluid to be heated passing through a heat exchange pipe in the evaporator, and a cooling operation for cooling. While performing the switching operation, stopping the cooling operation,
Or, during the switching operation from the cooling operation, an absorption refrigerator that performs a dilution operation of diluting the concentration of the absorbent in the absorbent, a pipe attached to the high-temperature regenerator, An anti-freezing heat exchanging means provided with a heating heat exchanger for preventing freezing of the heated operation fluid; and supplying the heated operation fluid to the heating heat exchanger during the dilution operation to heat the dilution. An absorption refrigerator comprising heating means.