JP7365612B2 - Absorption chiller, absorption chiller control method and controller - Google Patents

Description

The present invention relates to an absorption refrigerating machine and a control method for an absorption refrigerating machine, and in particular, an absorption refrigerating machine that can improve COP and reduce combustion consumption even when the cooling load is low. and a method of controlling an absorption chiller.

BACKGROUND ART Absorption refrigerators are generally known that include a high-temperature regenerator, a low-temperature regenerator, an evaporator, a condenser, and an absorber, which are connected by piping to form circulation paths for an absorption liquid and a refrigerant, respectively. Absorption chillers are used, for example, in central air conditioning in office buildings.
Conventionally, as such an absorption refrigerator, for example, a pressure adjustment means and an intermediate regenerator are installed in an absorption solution line that communicates between a high temperature regenerator and a low temperature regenerator or an absorption solution line that communicates between a low temperature regenerator and an absorber. The intermediate regenerator exchanges sensible heat and latent heat between the fluid supplied from the external heat source and the absorption solution flowing through the absorption solution line, and measures the cold and hot water outlet temperature and the temperature of the high temperature regenerator. A device is disclosed that includes a temperature measuring means and a fuel supply amount control mechanism that adjusts the amount of high quality fuel supplied to the high quality fuel combustion burner based on the cold/hot water outlet temperature and the temperature of the high temperature regenerator. (For example, see Patent Document 1).

Patent No. 3114850

In conventional technology, the degree of opening of the burner is controlled according to the cooling load to improve COP (Coefficient of Performance).
In this case, the burner is controlled according to the temperature of the cold water, and the burner is turned off when the temperature of the cold water reaches a predetermined temperature. Therefore, when the cooling load becomes low, for example, below 20%, the burner has to be repeatedly turned on and off.
Normally, when ON/OFF control of the burner is performed, the combustion amount of the burner temporarily becomes 50 to 100% at maximum. Therefore, when the cooling load is low, there is a problem in that the temperature of the chilled water decreases excessively and the COP also decreases. In particular, in office buildings and stores, the operating time is the longest when the cooling load is less than 20%, so it is important to improve COP and reduce fuel consumption when the cooling load is low. desired.

The present invention has been made in view of the above-mentioned circumstances, and provides an absorption chiller and absorption chiller control that can improve COP and reduce combustion consumption even when the cooling load is low. The purpose is to provide a method.

In order to achieve the above object, the absorption refrigerating machine of the present invention includes a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser, and an absorber, which are connected by piping to provide circulation paths for the absorption liquid and the refrigerant, respectively. The absorption refrigerator includes a control device, and the control device determines that the cooling load is equal to or less than a first predetermined value, and the time during which the combustion of the gas burner is OFF is determined to be a predetermined time. If it is determined that the fuel control valve of the gas burner continues, the maximum valve opening of the fuel control valve of the gas burner is set to a predetermined valve opening, and the predetermined valve opening is a valve at which ON/OFF repeat control of the gas burner is started. It is characterized by an opening degree .
According to this, it is possible to prevent an increase in the number of ON/OFF operations 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 decreases, it is possible to prevent the chilled water temperature from excessively decreasing due to excessive combustion of the gas burner, improve the COP, and reduce the fuel consumption of the gas burner. It becomes possible.

A schematic configuration diagram of an absorption chiller according to an embodiment of the present invention Block diagram showing the control configuration of this embodiment Flowchart showing the operation of this embodiment

The first invention is an absorption refrigerator comprising a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser, and an absorber, which are connected by piping to form circulation paths for absorption liquid and refrigerant, respectively. The control device is configured to control the gas burner when it is determined that the cooling load is below a predetermined value and the combustion of the gas burner is determined to be OFF for a predetermined period of time. Controls the valve opening of the fuel control valve to be small.
According to this, when the cooling load decreases, it is possible to prevent excessive combustion of the gas burner, it is possible to prevent the chilled water temperature from decreasing excessively due to excessive combustion of the gas burner, and it is possible to improve the COP. , it becomes possible to reduce the fuel consumption of the gas burner.

In a second aspect of the invention, the control device controls the valve opening of the fuel control valve of the gas burner to return to its original value when a state in which the cooling load is equal to or higher than a predetermined value continues for a predetermined period of time.
According to this, when the cooling load increases, the maximum valve opening of the fuel control valve can be returned to the maximum opening, and appropriate control can be performed using the normal maximum valve opening.

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

A fourth invention provides control of an absorption refrigerator comprising a high-temperature regenerator, a low-temperature regenerator, an evaporator, a condenser, and an absorber, and these are connected via piping to form circulation paths for absorption liquid and refrigerant, respectively. The method includes the step of reducing the valve opening of the fuel control valve of the gas burner when the cooling load is below a predetermined value and the combustion of the gas burner continues for a predetermined period of time. has.
According to this, when the cooling load decreases, it is possible to prevent excessive combustion of the gas burner, it is possible to prevent the chilled water temperature from decreasing excessively due to excessive combustion of the gas burner, and it is possible to improve the COP. , it becomes possible to reduce the fuel consumption of the gas burner.

A fifth aspect of the present invention further includes the step of returning the valve opening of the fuel control valve of the gas burner to its original value when the state in which the cooling load is equal to or higher than a predetermined value continues for a predetermined period of time.
According to this, when the cooling load increases, the maximum valve opening of the fuel control valve can be returned to the maximum opening, and appropriate control can be performed using the normal maximum valve opening.

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

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an absorption refrigerator according to this embodiment. The absorption chiller 100 is an absorption chiller/heater that uses water as a refrigerant, a lithium bromide (LiBr) aqueous solution 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 arranged in parallel with the evaporator 1, and an evaporator-absorber shell 3 housing the evaporator 1 and absorber 2. , a high-temperature regenerator 5 equipped with a gas burner 4, a low-temperature regenerator 6, a condenser 7 installed in parallel with the low-temperature regenerator 6, and a low-temperature regenerator condenser housing the low-temperature regenerator 6 and condenser 7. A container body 8 is provided.
The absorption chiller 100 also includes a low temperature heat exchanger 12, a high temperature heat exchanger 13, a refrigerant drain heat recovery device 17, a dilute absorption liquid pump 45, a concentrated absorption liquid pump 47, and a refrigerant pump 48. Each of these devices is connected via pipes such as absorption liquid pipes 21, 23, 24, 25 and refrigerant pipes 31, 32, 34, 35 to form a circulation path.

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

The absorber 2 has a function of causing the refrigerant vapor evaporated in the evaporator 1 to be absorbed into an absorption liquid and maintaining the pressure inside the evaporator-absorber shell 3 in a high vacuum state. A dilute absorption liquid reservoir 2A is formed in the lower part of the absorber 2, in which a diluted absorption liquid that has absorbed refrigerant vapor accumulates. One end of the liquid pipe 21 is connected. The dilute absorption liquid pipe 21 includes a branched dilute absorption liquid pipe 21A that branches on the downstream side of the dilute absorption liquid pump 45. The dilute absorption liquid pump 45 is a pump that can be controlled by an inverter, and is configured such that the driving amount of the dilute absorption liquid pump 45 can be varied by controlling the inverter frequency.
This branched rare absorption liquid pipe 21A passes through the refrigerant drain heat recovery device 17, and then joins the rare absorption liquid pipe 21 again on the downstream side of the low temperature heat exchanger 12 of the rare absorption liquid pipe 21. The other end of the diluted absorption liquid pipe 21 passes through the high temperature heat exchanger 13 and then opens into the gas layer section 5B located above the heat exchange section 5A formed in the high temperature regenerator 5.
The dilute 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 opens into the low temperature regenerator 6.

The high-temperature regenerator 5 is configured by housing a gas burner 4 in a shell 60, and a heat exchange section 5A is formed above the gas burner 4 to heat and regenerate the absorption liquid using the flame of the gas burner 4 as a heat source. An exhaust path 40 through which exhaust gas combusted by the gas burner 4 flows is connected to the heat exchange section 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. A control valve 64 is provided to control the amount of. A gas flow meter 65 is provided in the gas pipe 61 .

An intermediate absorption liquid reservoir 5C is formed on the side of the heat exchange part 5A, in which the intermediate absorption liquid that flows out from the heat exchange part 5A after being heated and regenerated in the heat exchange part 5A is collected. One end of a second intermediate absorption liquid pipe 23 is connected to the lower end of this intermediate absorption liquid reservoir 5C, and a high temperature heat exchanger 13 is provided in this second intermediate absorption liquid pipe 23. This high-temperature heat exchanger 13 heats the absorption liquid flowing through the dilute absorption liquid pipe 21 with the heat of the high-temperature intermediate absorption liquid flowing out from the intermediate absorption liquid reservoir 5C, and reduces the fuel consumption 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 absorption liquid pipe 23 is connected to a concentrated absorption liquid pipe 25 that connects 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. A heat transfer tube 31A formed as a part of the refrigerant pipe 31 extending from the upper end of the high temperature regenerator 5 to the bottom of the low temperature regenerator 6 is disposed. By circulating refrigerant vapor through this refrigerant pipe 31, the heat of the refrigerant vapor is transferred to the absorption liquid accumulated in the absorption liquid reservoir 6A via the heat transfer tube 31A, and this absorption liquid is further concentrated.
One end of a concentrated absorption liquid pipe 25 is connected to the absorption liquid reservoir 6A of the low-temperature regenerator 6, and the other end of this concentrated absorption liquid pipe 25 is connected to a concentrated liquid distribution device provided above the gas layer section 2B of the absorber 2. Connected to 2C. The concentrated absorption liquid pipe 25 is provided with a concentrated absorption liquid pump 47 and a low temperature heat exchanger 12. This low temperature heat exchanger 12 heats the dilute absorption liquid flowing through the dilute absorption liquid pipe 21 with the heat of the concentrated absorption liquid flowing out from the absorption liquid reservoir 6A of the low temperature regenerator 6.

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

As described above, the gas 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 piped to the absorption liquid reservoir 6A of the low-temperature regenerator 6 and a refrigerant drain heat recovery device 17. The upstream side of the heat transfer tube 31A of the refrigerant pipe 31 and the gas layer portion 2B of the absorber 2 are connected by a refrigerant pipe 32 with an on-off valve V2 interposed therebetween.
Further, one end of a refrigerant pipe 34 through which the refrigerant flowing out from the refrigerant reservoir 7A flows is connected to the refrigerant reservoir 7A of the condenser 7, and the other end of the refrigerant tube 34 is connected to a downwardly curved U-seal portion 34A. It is connected to the gas layer section 1A of the evaporator 1 via.
A refrigerant liquid reservoir 1B in which liquefied refrigerant accumulates is formed below the evaporator 1, and a refrigerant pump 48 connects this refrigerant liquid reservoir 1B and a diffuser 1C disposed above the air layer 1A of the evaporator 1. The refrigerant pipe 35 is connected to the intervening refrigerant pipe 35 .

The cold water pipe 14 is also provided with a cold water inlet temperature sensor 80 that detects the temperature of the cold water flowing through the cold water pipe 14 on the inlet side, and a cold water outlet temperature sensor 81 that detects the temperature of the cold water on the outlet side.
Furthermore, a cooling water inlet temperature sensor 83 is provided on the inlet side of the cooling water pipe 15 to detect the temperature on the inlet side of the cooling water.

Further, the absorption refrigerator 100 of this embodiment includes an air extraction device 70, and the air extraction device 70 includes a tank 71. An air bleed pipe 72 communicating with the gas layer section 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 . Furthermore, an absorption liquid pipe 75 connected to the dilute absorption 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 dilute absorption liquid in the dilute absorption liquid pipe 21 is taken into the tank 71 via the absorption liquid pipe 75. The diluted absorption liquid flowing in through the absorption liquid pipe 75 creates a negative pressure inside the tank 71, and as a result, not only the non-condensable gas stored in the upper part of the absorber 2, but also refrigerant vapor, vaporized absorption liquid, etc. are extracted. It is guided above the tank 71 through the trachea 72.

Among the gases led to the tank 71, the refrigerant vapor and the vaporized absorption liquid dissolve into the absorption liquid accumulated below the tank 71 and are absorbed, but the non-condensable gas cannot dissolve into the absorption liquid. It is stored above the tank 71. The absorbent liquid accumulated below the tank 71 is returned to the absorber 2 through the return pipe 73.

Next, the control configuration of this embodiment will be explained.
FIG. 2 is a block diagram showing the control configuration of this embodiment.
As shown in FIG. 2, the absorption refrigerator 100 of this 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 chiller 100, and includes a CPU as an arithmetic execution section, and a ROM that non-volatilely stores basic control programs executable by the CPU, predetermined data, etc. , a memory 52 such as a RAM that volatilely stores predetermined data, and other peripheral circuits.

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

The control device 51 of the controller 50 controls the fuel control valve 64 of the gas burner 4 of the absorption refrigerator 100 to control combustion by the gas burner 4, and also controls the dilute absorption liquid pump 45, the concentrated absorption liquid pump 47, and the refrigerant pump. 48 drive controls. Furthermore, the control device 51 of the controller 50 performs inverter control of the dilute absorption liquid pump 45, concentrated absorption liquid pump 47, and refrigerant pump 48, thereby controlling the flow rate of the dilute absorption liquid pump 45, concentrated absorption liquid pump 47, and refrigerant pump 48. configured to perform control. Further, the control device 51 is configured to perform opening/closing control of each valve V1, V2.

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

In this embodiment, the control device 51 determines whether the cooling load is less than or equal to a predetermined value during cooling operation. Here, the predetermined value of the cooling load is the value of the cooling load at which ON/OFF repetitive control of the gas burner 4 is started, and specifically, the predetermined value is set to a cooling load of about 15% to 20%. .
When the control device 51 determines that the cooling load is below a predetermined value and also determines that the combustion of the gas burner 4 continues for a predetermined period of time, the control device 51 closes the fuel control valve 64 of the gas burner 4. control so that the maximum valve opening is fixed at the minimum opening.
Here, the predetermined time during which the combustion of the gas burner 4 is OFF is set to, for example, 900 seconds. However, in order to stop the combustion of the gas burner 4, at least about 4 minutes (240 seconds) is required, so 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 lowest valve opening degree at which ON/OFF repetitive control of the gas burner 4 is started. Specifically, when the maximum valve opening degree is 100%, the maximum The valve opening is about 15% of the valve opening. This prevents excessive combustion in 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 a predetermined value continues for a predetermined period of time, the control device 51 changes the maximum valve opening of the fuel control valve 64 of the gas burner 4 from the minimum opening to the maximum opening (100%). control to return it. The predetermined value of the cooling load is a value of the cooling load that enables inverter control of the gas burner 4, and specifically, the predetermined value is set to a cooling load of about 15% to 20%.

Next, the operation of this embodiment will be explained.
During 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 controls the amount of heat input to the absorption chiller 100 so that the brine outlet temperature of the evaporator 1 (the temperature detected by the cold water outlet temperature sensor 81) reaches a predetermined set temperature, for example, 7°C. is controlled.
Specifically, the control device 51 starts all the pumps 45, 47, and 48, and controls the combustion of gas in the gas burner 4, so that the temperature of the brine measured by the cold water outlet temperature sensor 81 reaches a predetermined level. The thermal power of the gas burner 4 is controlled so that the temperature is 7°C.

In this case, the diluted absorption liquid from the absorber 2 is heated by the diluted absorption liquid pump 45 via the diluted absorption 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.
The absorption liquid sent to the high-temperature regenerator 5 is heated in the high-temperature regenerator 5 by the flame of the gas burner 4 and the high-temperature combustion gas, so that the refrigerant in the absorption liquid is evaporated and separated. The intermediate absorption liquid whose concentration has increased by evaporating and separating the refrigerant in the high-temperature regenerator 5 is sent to the concentrated absorption liquid pipe 25 via the high-temperature heat exchanger 13, and joins with the absorption liquid that has passed through the low-temperature regenerator 6. .

On the other hand, the absorption liquid sent to the low-temperature regenerator 6 is heated by high-temperature refrigerant vapor that is supplied from the high-temperature regenerator 5 via the refrigerant pipe 31 and flows into the heat transfer tube 31A, and the refrigerant is further separated to reduce the concentration. This concentrated absorption liquid merges with the absorption liquid that has passed through the high-temperature regenerator 5, and 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 concentrated liquid dispersion unit 2C. distributed from.

The refrigerant separated and produced in the low-temperature regenerator 6 enters the condenser 7, condenses, and accumulates in the refrigerant liquid reservoir 7A. When a large amount of refrigerant liquid accumulates 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 up by the operation of the refrigerant pump 48, and is dispersed. The heat exchanger tube 14A of the cold water pipe 14 is sprayed from the container 1C.
The refrigerant liquid spread over the heat exchanger tubes 14A takes vaporization heat from the brine passing inside the heat exchanger tubes 14A and evaporates, so the brine passing inside the heat exchanger tubes 14A is cooled, and the brine whose temperature has been lowered in this way is The cold water is supplied to the heat load from the cold water pipe 14 to perform cooling operations such as air conditioning.
Then, the refrigerant evaporated in the evaporator 1 enters the absorber 2, is absorbed by the concentrated absorption liquid supplied from the low-temperature regenerator 6 and sprayed from above, and accumulates in the diluted absorption liquid reservoir 2A of the absorber 2. The absorption liquid pump 45 transports the absorption liquid to the high temperature regenerator 5 and repeats the circulation.

Next, the control operation according to this embodiment will be explained with reference to the flowchart shown in FIG.
In this embodiment, when the cooling operation is started (ST1), the control device 51 determines whether the cooling load is less than or equal to a predetermined value (ST2).
If it is determined that the cooling load is below the predetermined value (ST2: YES), the control device 51 determines whether the fuel control valve 64 of the gas burner 4 is turned off (ST3). If the control device 51 determines that the cooling load is below a predetermined value and the fuel control valve 64 of the gas burner 4 remains OFF for a predetermined period of time (900 seconds) (ST4: YES), The maximum valve opening of the fuel control valve 64 is controlled to be fixed at the minimum opening (ST5).

When the cooling capacity is below a predetermined value, the control device 51 continues to operate with the minimum opening of the fuel control valve 64 always set as the maximum valve opening.
Thereby, an increase in the number of times the gas burner 4 is turned on and off can be prevented, and excessive combustion of the gas burner 4 can be prevented. As a result, it is possible to prevent the cold water temperature from decreasing excessively due to excessive combustion in the gas burner 4, and it is possible to improve the COP and reduce the fuel consumption of the gas burner 4.
According to experiments conducted by the inventors, the fluctuation range of the cold water temperature by controlling the gas burner 4 of the present invention was 5.4 to 7.4°C, whereas the fluctuation range of the cold water temperature by controlling the gas burner 4 of the present invention was The temperature fluctuation range was reduced to 5.9 to 7.4°C, resulting in an approximately 11% improvement in COP.

If the control device 51 determines that the cooling capacity has exceeded a predetermined value during operation (ST6: YES) and this state has continued for a predetermined time (ST7: YES), the control device 51 controls the fuel control valve 64. The maximum valve opening is controlled to return from the minimum opening to the maximum opening (ST8).

As explained above, in the present embodiment, the control device 51 determines that the cooling load is below 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 continues, the maximum valve opening degree of the fuel control valve 64 of the gas burner 4 is controlled to be fixed at the minimum opening degree.
According to this, it is possible to prevent excessive combustion of the gas burner 4, it is possible to prevent the cold water temperature from decreasing excessively due to excessive combustion of the gas burner 4, and it is possible to improve the COP, and also to improve the fuel consumption of the gas burner 4. It becomes possible to reduce the amount.

Further, in the present embodiment, the control device 51 controls the maximum valve opening of the fuel control valve 64 of the gas burner 4 to return to the maximum opening when the cooling load remains at a predetermined value or more for a predetermined period of 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 using the normal maximum valve opening degree.

Note that this embodiment shows one mode to which the present invention is applied, and the present invention is not limited to the above embodiment.
For example, in this embodiment, control during cooling operation has been described, but the control can be similarly applied during heating operation. In this case, when the heating load falls below a predetermined value (for example, 15 to 20% or less) and the fuel control valve 64 remains OFF for a predetermined period of time, the maximum valve opening of the fuel control valve 64 is set to the minimum opening. It may be fixed at a certain time.

Furthermore, although a configuration has been described in which the high temperature regenerator 5 includes a gas burner 4 that heats the absorption liquid by burning fuel gas as a heating means, the structure is not limited to this. It is also possible to use a configuration that includes a gas burner that burns gas, or a configuration that uses heat from steam, exhaust gas, etc. for heating.

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

Claims (12)

An absorption refrigerating machine comprising a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser, and an absorber, which are connected via piping to form circulation paths for absorption liquid and refrigerant, respectively.
Equipped with a control device,
When the control device determines that the cooling load is less than or equal to a first predetermined value and determines that combustion of the gas burner continues for a predetermined period of time, the control device controls the fuel of the gas burner. The maximum valve opening of the valve is set to the specified valve opening,
The absorption refrigerator , wherein the predetermined valve opening degree is a valve opening degree at which ON/OFF repetitive control of the gas burner is started . The absorption refrigerator according to claim 1, wherein the first predetermined value is a cooling load at which repeated ON/OFF control of the gas burner is started . 2. The control device sets the maximum valve opening of the fuel control valve of the gas burner to the maximum opening when the cooling load continues to be equal to or higher than a second predetermined value for a predetermined period of time. The absorption refrigerator according to item 2. 4. The absorption refrigerator according to claim 3 , wherein the second predetermined value is a cooling load that enables inverter control in which repeated ON/OFF control of the gas burner is started. A method for controlling an absorption refrigerating machine comprising a high temperature regenerator, a low temperature regenerator, an evaporator, a condenser and an absorber, which are connected via piping to form circulation paths for absorption liquid and refrigerant, the method comprising:
When the cooling load is below the first predetermined value and the combustion of the gas burner continues for a predetermined period of time, the maximum valve opening of the fuel control valve of the gas burner is set to a predetermined valve opening. It has a step of
A method for controlling an absorption refrigerator , characterized in that the predetermined valve opening degree is a valve opening degree at which repeated ON/OFF control of the gas burner is started . 6. The absorption chiller control method according to claim 5 , wherein the first predetermined value is a cooling load at which repeated ON/OFF control of the gas burner is started . 5. The method further comprises the step of returning the maximum valve opening of the fuel control valve of the gas burner to the maximum opening when the state in which the cooling load is equal to or higher than a second predetermined value continues for a predetermined period of time. Or the method for controlling an absorption refrigerator according to claim 6. 8. The absorption chiller control method according to claim 7, wherein the second predetermined value is a cooling load that enables inverter control of the gas burner. A controller for controlling an absorption refrigerator comprising a high-temperature regenerator, a low-temperature regenerator, an evaporator, a condenser, and an absorber, which are connected via piping to form circulation paths for absorption liquid and refrigerant, respectively,
When it is determined that the cooling load is less than or equal to the first predetermined value, and when it is determined that the combustion of the gas burner continues for a predetermined period of time, the maximum valve opening of the fuel control valve of the gas burner is determined. to the specified valve opening degree,
The controller, wherein the predetermined valve opening degree is a valve opening degree at which ON/OFF repetitive control of the gas burner is started. 10. The controller according to claim 9, wherein the first predetermined value is a cooling load at which repeated ON/OFF control of the gas burner is started. 11. The maximum valve opening of the fuel control valve of the gas burner is set to the maximum opening when a state in which the cooling load is equal to or higher than a second predetermined value continues for a predetermined period of time. controller. The controller according to claim 11, wherein the second predetermined value is a cooling load that enables inverter control of the gas burner.

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