JP7054855B2 - Absorption chiller - Google Patents

Description

The present invention relates to an absorption chiller, and more particularly to an absorption chiller capable of improving COP even when the cooling load is low and reducing the amount of combustion used.

Generally, an absorption chiller having a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser and an absorber, and connecting these with pipes to form a circulation path for an absorbent liquid and a refrigerant is known. The absorption chiller is used, for example, for central air conditioning in office buildings.
As such an absorption chiller, conventionally, for example, a pressure adjusting means and an intermediate regenerator are provided in an absorption solution line connecting a high temperature regenerator and a low temperature regenerator or an absorption solution line communicating a low temperature regenerator and an absorber. The intermediate regenerator performs sensible heat / latent heat exchange between the fluid supplied from the external heat source and the absorption solution flowing through the absorption solution line, and measures the temperature of the cold / hot water outlet and the temperature of the high temperature regenerator. Disclosed are those provided with a temperature measuring means and a fuel supply amount control mechanism for adjusting the amount of high quality fuel supplied to the burner for high quality fuel combustion based on the temperature of the hot / cold water outlet and the temperature of the high temperature regenerator. (See, for example, Patent Document 1).

Japanese Patent No. 3114850

In the conventional technique, the opening degree of the burner is controlled according to the cooling load to improve the COP (Coefficient of Performance: "coefficient of performance").
In this case, the burner is controlled according to the chilled water temperature, and the burner is turned off when the chilled water temperature reaches a predetermined temperature. Therefore, when the cooling load becomes low, for example, the cooling load is 20% or less, the burner is repeatedly turned on and off, and the patient has been waiting.
Normally, when the ON / OFF control of the burner is performed, the combustion amount temporarily reaches a maximum of 50 to 100% when the burner is burned. Therefore, when the cooling load is low, there is a problem that the cold water temperature is excessively lowered and the COP is also lowered. In particular, in office buildings and stores, the operating time when the cooling load is 20% or less is the longest, so when the cooling load is low like this, it is possible to improve COP and reduce fuel consumption. It is desired.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an absorption chiller capable of improving COP even when the cooling load is low and reducing the amount of combustion used. It is something to do.

In order to achieve the above object, the present invention includes a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser and an absorber, and these are connected by piping to form an absorption liquid and a circulation path of the refrigerant, respectively. The chiller chiller is provided with a control device, and the control device determines that the cooling load is equal to or less than a predetermined value, and determines that the time during which the combustion of the gas burner is OFF continues for a predetermined time. In addition, it is characterized in that the maximum valve opening degree of the fuel control valve of the gas burner is controlled to be fixed to the minimum opening degree.
According to this, it is possible to prevent an increase in the number of ON / OFF times of the gas burner, and it is possible to prevent excessive combustion of the gas burner.

According to the present invention, when the cooling load is reduced, it is possible to prevent an excessive decrease in the chilled water temperature due to excessive combustion of the gas burner, improve the COP, and reduce the fuel consumption of the gas burner. It will be possible.

The schematic block diagram of the absorption chiller which concerns on embodiment of this invention. The block diagram which shows the control composition of this embodiment. The flowchart which shows the operation of this embodiment.

The first invention is an absorption chiller comprising a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser and an absorber, which are connected by pipes to form circulation paths for an absorbent liquid and a refrigerant, respectively. A control device is provided, and when the control device determines that the cooling load is equal to or less than a predetermined value and determines that the time during which the combustion of the gas burner is OFF continues for a predetermined time, the gas burner is used. The maximum valve opening of the fuel control valve is controlled to be fixed to the minimum opening.
According to this, when the cooling load is reduced, excessive combustion of the gas burner can be prevented, excessive combustion of the gas burner can be prevented, and the cold water temperature can be prevented from being excessively lowered, and COP can be improved. , It becomes possible to reduce the fuel consumption of the gas burner.

According to the second aspect of the present invention, the control device controls so that the maximum valve opening degree of the fuel control valve of the gas burner is returned to the maximum opening degree when the cooling load continues to be at least a predetermined value for a predetermined time.
According to this, when the cooling load increases, the maximum valve opening degree of the fuel control valve can be returned to the maximum opening degree, and appropriate control can be performed by the normal maximum valve opening degree.

In the third invention, the predetermined value is a cooling load at which ON / OFF repeated control of the gas burner is started.
According to this, it is possible to prevent an increase in the number of ON / OFF times of the gas burner, and it is possible to prevent excessive combustion of the gas burner.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an absorption chiller according to the present embodiment. The absorption chiller 100 is an absorption chiller-heater that uses water as a refrigerant and an aqueous solution of lithium bromide (LiBr) as an absorption liquid, and heats the absorption liquid with gas fuel.

As shown in FIG. 1, the absorption chiller 100 includes an evaporator 1, an absorber 2 juxtaposed to the evaporator 1, and an evaporator absorber body 3 containing the evaporator 1 and the absorber 2. A high-temperature evaporator 5 equipped with a gas burner 4, a low-temperature evaporator 6, a condenser 7 juxtaposed to the low-temperature evaporator 6, and a low-temperature evaporator containing these low-temperature evaporator 6 and the condenser 7. It is provided with an instrument body 8.
Further, the absorption chiller 100 includes a low temperature heat exchanger 12, a high temperature heat exchanger 13, a refrigerant drain heat recovery device 17, a rare absorbent liquid pump 45, a concentrated absorbent liquid pump 47, and a refrigerant pump 48. Each of these devices is connected by a pipe via an absorption liquid pipe 21, 23, 24, 25, a refrigerant pipe 31, 32, 34, 35, or the like to form a circulation path.

The evaporator 1 is provided with a chilled water pipe 14 for circulating and supplying brine that has exchanged heat with a refrigerant in the evaporator 1 to a heat load (for example, an air conditioner) (not shown). A heat transfer tube 14A formed in a part thereof is arranged in the evaporator 1.
The absorber 2 and the condenser 7 are provided with a cooling water pipe 15 for sequentially flowing cooling water to the absorber 2 and the condenser 7, and each heat transfer tube 15A formed in a part of the cooling water pipe 15 is provided. , 15B are arranged in the absorber 2 and the condenser 7, respectively.

The absorber 2 has a function of absorbing the refrigerant vapor evaporated by the evaporator 1 in the absorbing liquid and keeping the pressure in the evaporator absorber body 3 in a high vacuum state. At the lower part of the absorber 2, a rare absorption liquid reservoir 2A for absorbing the refrigerant vapor and accumulating the dilute rare absorption liquid is formed, and the rare absorption liquid reservoir 2A has a rare absorption liquid pump 45. One end of the liquid tube 21 is connected. The rare absorption liquid pipe 21 includes a branched rare absorption liquid pipe 21A that branches on the downstream side of the rare absorption liquid pump 45. The rare absorbent liquid pump 45 is a pump that can be controlled by an inverter, and is configured so that the drive amount of the rare absorbent liquid pump 45 can be changed by controlling the inverter frequency.
The branched rare absorption liquid pipe 21A rejoins the rare absorption liquid pipe 21 on the downstream side of the low temperature heat exchanger 12 of the rare absorption liquid pipe 21 after passing through the refrigerant drain heat recovery device 17. The other end of the rare absorption liquid tube 21 is opened to the air layer portion 5B located above the heat exchange portion 5A formed in the high temperature regenerator 5 after passing through the high temperature heat exchanger 13.
The rare absorption liquid pipe 21 is branched into a second branch pipe 21B on the downstream side of the low temperature heat exchanger 12, and the second branch pipe 21B is open in the low temperature regenerator 6.

The high temperature regenerator 5 is configured by accommodating the gas burner 4 in the shell 60, and a heat exchange unit 5A for heating and regenerating the absorbed liquid using the flame of the gas burner 4 as a heat source is formed above the gas burner 4. An exhaust path 40 through which the exhaust gas burned by the gas burner 4 flows is connected to the heat exchange unit 5A, and an exhaust gas heat exchanger 41 is provided in the exhaust path 40. Further, the gas burner 4 is connected to a gas pipe 61 to which fuel gas is supplied and an intake pipe 63 to which air from a blower 62 is supplied, and the gas pipe 61 and the intake pipe 63 are connected with fuel gas and air. A control valve 64 for controlling the amount of the gas is provided. The gas pipe 61 is provided with a gas flow meter 65.

On the side of the heat exchange unit 5A, an intermediate absorption liquid reservoir 5C is formed in which the intermediate absorption liquid that has flowed out from the heat exchange unit 5A after being heat-regenerated by the heat exchange unit 5A is collected. One end of the second intermediate absorption liquid pipe 23 is connected to the lower end of the intermediate absorption liquid reservoir 5C, and the second intermediate absorption liquid pipe 23 is provided with a high temperature heat exchanger 13. The high temperature heat exchanger 13 heats the absorption liquid flowing through the rare absorption liquid tube 21 by the heat of the high temperature intermediate absorption liquid flowing out from the intermediate absorption liquid reservoir 5C, and consumes fuel of the gas burner 4 in the high temperature regenerator 5. We are trying to reduce the amount.
The other end of the second intermediate absorbing liquid tube 23 is connected to the concentrated absorbing liquid tube 25 connecting the low temperature regenerator 6 and the absorber 2. Further, the upstream side of the high temperature heat exchanger 13 of the second intermediate absorption liquid pipe 23 and the absorber 2 are connected by an absorption liquid pipe 24 in which an on-off valve V1 is interposed.

The low-temperature regenerator 6 uses the refrigerant vapor separated by the high-temperature regenerator 5 as a heat source to heat and regenerate the absorption liquid accumulated in the absorption liquid reservoir 6A formed in the low-temperature regenerator 6, and regenerates the absorption liquid. A heat transfer tube 31A formed in a part of the refrigerant tube 31 extending from the upper end of the high temperature regenerator 5 to the bottom of the low temperature regenerator 6 is arranged in the room. By circulating the refrigerant steam through the refrigerant pipe 31, the heat of the refrigerant steam is transferred to the absorption liquid stored in the absorption liquid reservoir 6A through the heat transfer pipe 31A, and the absorption liquid is further concentrated.
One end of the concentrated absorbing liquid tube 25 is connected to the absorbing liquid reservoir 6A of the low temperature regenerator 6, and the other end of the concentrated absorbing liquid tube 25 is a concentrated liquid sprayer provided in the upper part of the air layer portion 2B of the absorber 2. It is connected to 2C. The concentrated absorbing liquid tube 25 is provided with a concentrated absorbing liquid pump 47 and a low temperature heat exchanger 12. The low temperature heat exchanger 12 heats the rare absorption liquid flowing through the rare absorption liquid tube 21 by the heat of the concentrated absorption liquid flowing out from the absorption liquid reservoir 6A of the low temperature regenerator 6.

Further, the concentrated absorbing liquid pipe 25 is provided with a bypass pipe 27 that bypasses the concentrated absorbing liquid pump 47 and the low temperature heat exchanger 12.
When the operation of the concentrated absorbing liquid pump 47 is stopped, the absorbing liquid collected in the absorbing liquid reservoir 6A of the low temperature regenerator 6 is supplied into the absorber 2 through the concentrated absorbing liquid pipe 25 and the bypass pipe 27.

As described above, the air layer portion 5B of the high temperature regenerator 5 and the refrigerant liquid reservoir 7A formed at the bottom of the condenser 7 are connected by the refrigerant pipe 31. The refrigerant pipe 31 includes a heat transfer pipe 31A and a refrigerant drain heat recovery device 17 piped to the absorption liquid reservoir 6A of the low temperature regenerator 6. The upstream side of the heat transfer pipe 31A of the refrigerant pipe 31 and the air layer portion 2B of the absorber 2 are connected by a refrigerant pipe 32 having an on-off valve V2 interposed therebetween.
Further, one end of a refrigerant pipe 34 through which the refrigerant flowing out of the refrigerant liquid pool 7A flows is connected to the refrigerant liquid reservoir 7A of the condenser 7, and the other end of the refrigerant pipe 34 is a downwardly curved U-seal portion 34A. It is connected to the air layer portion 1A of the evaporator 1 via.
Below the evaporator 1, a refrigerant liquid reservoir 1B in which the liquefied refrigerant is stored is formed, and the refrigerant pump 48 is the refrigerant liquid reservoir 1B and the spreader 1C arranged above the air layer portion 1A of the evaporator 1. It is connected to the intervening by a refrigerant pipe 35.

Further, the chilled water pipe 14 is provided with a chilled water inlet temperature sensor 80 for detecting the temperature on the inlet side of the chilled water flowing through the chilled water pipe 14 and a chilled water outlet temperature sensor 81 for detecting the temperature on the outlet side of the chilled water.
Further, on the inlet side of the cooling water pipe 15, a cooling water inlet temperature sensor 83 for detecting the temperature on the inlet side of the cooling water is provided.

Further, the absorption chiller 100 of the present embodiment includes an air extraction device 70, and the air extraction device 70 includes a tank 71. An air extraction pipe 72 communicating with the air layer portion 2B of the absorber 2 is connected to the upper part of the tank 71. A return pipe 73 communicating with the lower part of the absorber 2 is connected to the bottom of the tank 71. Further, an absorbent liquid pipe 75 connected to the rare absorbent liquid pipe 21 via an ejector pump 74 is connected to the upper part of the tank 71.
Then, by driving the ejector pump 74, the rare absorption liquid of the rare absorption liquid pipe 21 is taken into the tank 71 via the absorption liquid pipe 75. The rare absorbent liquid that has flowed through the absorbent liquid pipe 75 creates a negative pressure inside the tank 71, which draws not only the non-condensable gas stored in the upper part of the absorber 2 but also the refrigerant vapor, the vaporized absorbent liquid, and the like. It is guided above the tank 71 through the trachea 72.

Of the gas guided to the tank 71, the absorption liquid vaporized as the refrigerant vapor dissolves in the absorption liquid accumulated under the tank 71 and is absorbed, but the non-condensable gas cannot dissolve in the absorption liquid. It is stored above the tank 71. Then, the absorbing liquid accumulated under the tank 71 is returned to the absorber 2 through the return pipe 73.

Next, the control configuration of the present embodiment will be described.
FIG. 2 is a block diagram showing a control configuration of the present embodiment.
As shown in FIG. 2, the absorption chiller 100 of the present embodiment includes a controller 50, and the controller 50 includes a control device 51. The control device 51 centrally controls each part of the absorption type refrigerating machine 100, and is a CPU as an arithmetic execution unit, a ROM that non-volatilely stores a basic control program that can be executed by this CPU, predetermined data, and the like. , A memory 52 such as a RAM that volatilely stores predetermined data and the like, and other peripheral circuits and the like are provided.

Further, the control device 51 is configured to receive detection signals of the chilled water inlet temperature sensor 80, the chilled water outlet temperature sensor 81, the cooling water inlet temperature sensor 83, and the gas flow meter 65, respectively.
Further, the controller 50 includes a timer 53, an operation unit 54, and a notification unit 55, respectively.

The control device 51 of the controller 50 controls the fuel control valve 64 of the gas burner 4 of the absorption chiller 100 to control the combustion by the gas burner 4, and also controls the combustion by the gas burner 4, the rare absorption liquid pump 45, the concentrated absorption liquid pump 47, and the refrigerant pump. It is configured to perform drive control of 48. Further, the control device 51 of the controller 50 controls the inverters of the rare absorbent liquid pump 45, the concentrated absorbent liquid pump 47 and the refrigerant pump 48, so that the flow rate by the rare absorbent liquid pump 45, the concentrated absorbent liquid pump 47 and the refrigerant pump 48 It is configured to provide control. Further, the control device 51 is configured to control the opening and closing of each of the valves V1 and V2.

In the present embodiment, when the cooling operation is started, the control device 51 detects the cold water inlet temperature by the cold water inlet temperature sensor 80 and the cold water outlet temperature by the cold water outlet temperature sensor 81. .. Further, the control device 51 detects the temperature on the inlet side of the cooling water by the cooling water inlet temperature sensor 83, and also detects the gas flow rate and the gas calorific value in the gas burner 4. The gas flow rate is detected by the gas flow meter 65.

In the present embodiment, the control device 51 determines whether or not the cooling load is equal to or less than a predetermined value during the cooling operation. Here, the predetermined value of the cooling load is the value of the cooling load at which the ON / OFF repeated control of the gas burner 4 is started. Specifically, the cooling load of about 15% to 20% is set to the predetermined value. ..
When the control device 51 determines that the cooling load is equal to or less than a predetermined value and determines that the state in which the combustion of the gas burner 4 is OFF continues for a predetermined time, the fuel control valve 64 of the gas burner 4 The maximum valve opening is controlled to be fixed to the minimum opening.
Here, the predetermined time during which the combustion of the gas burner 4 is turned off is set to, for example, 900 seconds. However, since it takes at least about 4 minutes (240 seconds) to stop the combustion of the gas burner 4, the predetermined time can be arbitrarily set as long as it is 240 seconds or more.
Further, the minimum opening degree of the fuel control valve 64 is the minimum valve opening degree at which ON / OFF repeated control of the gas burner 4 is started. Specifically, when the maximum valve opening degree is 100%, the maximum opening degree is reached. The valve opening is about 15% of the valve opening. This prevents excessive combustion of the gas burner 4.

Further, when the control device 51 determines that the state in which the cooling load is equal to or higher than the predetermined value continues for a predetermined time, the maximum valve opening of the fuel control valve 64 of the gas burner 4 is changed from the minimum opening to the maximum opening (100%). Control to return. The predetermined value of the cooling load is the value of the cooling load that enables the inverter control of the gas burner 4, and specifically, the cooling load of about 15% to 20% is set to the predetermined value.

Next, the operation of this embodiment will be described.
During the cooling operation, brine (for example, cold water) is circulated and supplied to a heat load (not shown) via the cold water pipe 14. The control device 51 puts heat into the absorption chiller 100 so that the outlet side temperature of the brine evaporator 1 (the temperature detected by the chilled water outlet temperature sensor 81) becomes a predetermined set temperature, for example, 7 ° C. Is controlled.
Specifically, the control device 51 starts all the pumps 45, 47, 48 and controls the combustion of the gas in the gas burner 4, so that the temperature of the brine measured by the chilled water outlet temperature sensor 81 is predetermined. The thermal power of the gas burner 4 is controlled so that the temperature becomes 7 ° C.

In this case, the rare absorbent liquid from the absorber 2 is heated by the rare absorbent liquid pump 45 via the rare absorbent liquid pipe 21 via the low temperature heat exchanger 12 and the high temperature heat exchanger 13 or the exhaust gas heat exchanger 41. It is sent to the high temperature regenerator 5.
Since the absorbent liquid sent to the high-temperature regenerator 5 is heated by the flame of the gas burner 4 and the high-temperature combustion gas in the high-temperature regenerator 5, the refrigerant in the absorbent liquid evaporates and separates. The intermediate absorbent liquid whose concentration has increased by evaporating and separating the refrigerant in the high-temperature regenerator 5 is sent to the concentrated absorbent liquid pipe 25 via the high-temperature heat exchanger 13 and merges with the absorbent liquid via the low-temperature regenerator 6. ..

On the other hand, the absorbing liquid sent to the low temperature regenerator 6 is heated by the high temperature refrigerant vapor supplied from the high temperature regenerator 5 via the refrigerant pipe 31 and flowing into the heat transfer tube 31A, and the refrigerant is further separated to increase the concentration. The concentration becomes higher, and this concentrated absorption liquid merges with the above-mentioned absorption liquid via the high temperature regenerator 5, is sent to the absorber 2 via the low temperature heat exchanger 12 by the concentrated absorption liquid pump 47, and is sent to the absorber 2 through the concentrated liquid spreader 2C. It is sprayed from.

The refrigerant separated and generated by the low temperature regenerator 6 enters the condenser 7, condenses, and accumulates in the refrigerant liquid reservoir 7A. Then, when a large amount of refrigerant liquid is accumulated in the refrigerant liquid reservoir 7A, this refrigerant liquid flows out from the refrigerant liquid reservoir 7A, enters the evaporator 1 via the refrigerant pipe 34, is pumped by the operation of the refrigerant pump 48, and is sprayed. It is sprayed from the vessel 1C onto the heat transfer tube 14A of the cold water tube 14.
Since the refrigerant liquid sprayed on the heat transfer tube 14A takes the heat of vaporization from the brine passing through the inside of the heat transfer tube 14A and evaporates, the brine passing through the inside of the heat transfer tube 14A is cooled, and thus the brine having a lowered temperature is released. The heat load is supplied from the cold water pipe 14, and a cooling operation such as cooling is performed.
Then, the refrigerant evaporated in the evaporator 1 enters the absorber 2, is absorbed by the concentrated absorbent liquid supplied from the low temperature regenerator 6 and sprayed from above, and accumulates in the rare absorbent liquid reservoir 2A of the absorber 2, which is rare. The circulation carried to the high temperature regenerator 5 by the absorbent liquid pump 45 is repeated.

Next, the control operation according to the present embodiment will be described with reference to the flowchart shown in FIG.
In the present embodiment, when the cooling operation is started (ST1), the control device 51 determines whether or not the cooling load is equal to or less than a predetermined value (ST2).
Then, when it is determined that the cooling load is equal to or less than a predetermined value (ST2: YES), the control device 51 determines whether or not the fuel control valve 64 of the gas burner 4 is OFF (ST3). When the control device 51 determines that the cooling load is equal to or less than a predetermined value and the fuel control valve 64 of the gas burner 4 is turned off for a predetermined time (900 seconds) (ST4: YES). The maximum valve opening degree of the fuel control valve 64 is controlled to be fixed to the minimum opening degree (ST5).

When the cooling capacity is equal to or less than a predetermined value, the control device 51 always keeps operating with the minimum opening degree of the fuel control valve 64 as the maximum valve opening degree.
As a result, it is possible to prevent an increase in the number of ON / OFF times of the gas burner 4, and it is possible to prevent excessive combustion of the gas burner 4. As a result, it is possible to prevent an excessive decrease in the chilled water temperature due to excessive combustion of the gas burner 4, improve the COP, and reduce the fuel consumption of the gas burner 4.
According to the experiments conducted by the inventors, the fluctuation range of the cold water temperature under the control of the conventional gas burner 4 was 5.4 to 7.4 ° C., whereas the fluctuation range of the cold water under the control of the gas burner 4 of the present invention was 5.4 to 7.4 ° C. The fluctuation range of the temperature was as small as 5.9 to 7.4 ° C., and the result was obtained that the COP was improved by about 11%.

When the cooling capacity of the control device 51 becomes equal to or higher than a predetermined value during operation (ST6: YES) and it is determined that this state has continued for a predetermined time (ST7: YES), the control device 51 of the fuel control valve 64 The maximum valve opening is controlled to return from the minimum opening to the maximum opening (ST8).

As described above, in the present embodiment, the control device 51 determines that the cooling load is equal to or less than a predetermined value in the cooling operation, and the time during which the combustion of the gas burner 4 is OFF is a predetermined time. When it is determined that the fuel control valve 64 of the gas burner 4 is continued, the maximum valve opening degree is controlled to be fixed to the minimum opening degree.
According to this, it is possible to prevent excessive combustion of the gas burner 4, prevent an excessive decrease in the cold water temperature due to excessive combustion of the gas burner 4, improve COP, and consume fuel of the gas burner 4. It is possible to reduce the amount.

Further, in the present embodiment, the control device 51 controls to return the maximum valve opening degree of the fuel control valve 64 of the gas burner 4 to the maximum opening degree when the cooling load continues to be a predetermined value or more for a predetermined time. do.
According to this, when the cooling load increases, the maximum valve opening degree of the fuel control valve 64 can be returned to the maximum opening degree, and appropriate control can be performed by the normal maximum valve opening degree.

It should be noted that the present embodiment shows one aspect to which the present invention is applied, and the present invention is not limited to the above-described embodiment.
For example, in the present embodiment, the control during the cooling operation has been described, but the same can be applied to the heating operation as well. In this case, when the heating load becomes a predetermined value or less (for example, 15 to 20% or less) and the fuel control valve 64 remains OFF for a predetermined time, the maximum valve opening of the fuel control valve 64 is opened at the minimum. It may be fixed at a certain time.

Further, the configuration including the gas burner 4 for burning the fuel gas to heat the absorption liquid in the high temperature regenerator 5 has been described, but the present invention is not limited to this, and for example, kerosene and heavy oil A are used. It may be configured to include a gas burner for burning the gas, or to be heated by using heat such as steam or exhaust gas.

1 Evaporator 2 Absorber 3 Absorber 4 Gas burner 5 High temperature regenerator 6 Low temperature regenerator 7 Condenser 45 Rare absorption liquid pump 47 Concentrated absorption liquid pump 48 Refrigerant pump 50 Controller 51 Control device 52 Memory 55 Notification unit 64 Fuel control valve 65 Gas flow meter 70 Air extractor 80 Cold water inlet temperature sensor 81 Cold water outlet temperature sensor 83 Cooling water inlet temperature sensor 100 Absorption chiller

Claims (3)

In an absorption chiller equipped with a high-temperature regenerator, a low-temperature regenerator, an evaporator, a condenser and an absorber, which are connected by piping to form a circulation path for an absorbent liquid and a refrigerant, respectively.
Equipped with a control device
The control device determines that the cooling load is equal to or less than a predetermined value, and determines that the time during which the combustion of the gas burner is OFF continues for a predetermined time, the maximum of the fuel control valve of the gas burner. An absorption chiller characterized by controlling the valve opening to be fixed at the minimum opening. The first aspect of the present invention is characterized in that the control device controls to return the maximum valve opening degree of the fuel control valve of the gas burner to the maximum opening degree when the cooling load continues to be at least a predetermined value for a predetermined time. The absorption chiller described. The absorption chiller according to claim 1 or 2, wherein the predetermined value is a cooling load in which ON / OFF repeated control of the gas burner is started.

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