JP4090135B2 - Control method of absorption refrigerator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control method at the time of startup of an absorption refrigerator.
[0002]
[Prior art]
In the absorption refrigerator, the refrigerant vapor generated by heating the solution in the regenerator is sent to the condenser, and the refrigerant liquid obtained by cooling with the cooling water in this condenser is sent to the evaporator to evaporate it. The fluid flowing through the heat transfer pipe piped inside is cooled by the evaporation heat of the refrigerant, and the cooled fluid is supplied to the cooled portion to perform a cooling operation such as cooling.
[0003]
When the fluid cooled through the heat transfer pipe installed in the evaporator is inexpensive and water that does not pose a risk of leakage, the operation of the chilled water pump that supplies the cooled water to the cooled part is stopped. If the refrigerant liquid accumulated in the refrigerant liquid reservoir is sprayed on the heat transfer tube by operating the refrigerant pump, the water in the heat transfer tube will freeze, so the chilled water pump is operated to prevent freezing of the chilled water system. Has been done from the beginning.
[0004]
[Problems to be solved by the invention]
However, in the conventional absorption refrigerator described above, the cooling water pump is operated from the beginning when there is no refrigeration capacity, and hot water spreads in the system and the temperature of the entire apparatus rises. There is a problem that it cannot be done, and this solution has been an issue.
[0005]
[Means for Solving the Problems]
In the present invention, as a specific means for solving the above-described problems of the prior art, the heat of evaporation is deprived from the refrigerant in the heat transfer pipes piped in the regenerator / condenser / absorber and the evaporator constituting the refrigeration cycle. At the start of the absorption chiller that supplies the cooled fluid to the part to be cooled and starts cooling, the heating of the absorption liquid in the regenerator and the supply of cooling water to the absorber and condenser are started in advance. Then, at least one of the internal pressure of the evaporator and / or the absorber, the temperature of the refrigerant supplied from the condenser and flushed by the evaporator, and the temperature of the absorbing liquid supplied from the regenerator to the absorber Based on the above, the operation of the pump for supplying the fluid to the part to be cooled is started, and the operation of the refrigerant pump for spraying the refrigerant liquid supplied from the condenser and accumulated in the refrigerant liquid reservoir to the heat transfer pipe The first to start And the control method,
[0006]
In the control method of the first configuration, when the operation of the pump for supplying the fluid to the cooled part is started, the inside of the evaporator and / or the absorber shows a pressure drop exceeding a set value, or the condenser When the refrigerant supplied from the flasher and flashing in the evaporator shows a temperature drop exceeding the set value, or when the absorption liquid supplied from the regenerator to the absorber shows a temperature rise exceeding the set value, the refrigerant pump is operated. A second control method in which the operation of the absorption refrigerator is stopped without starting
By providing the above, the above-described problems of the prior art are solved.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
The example illustrated in FIG. 1 is a double-effect absorption refrigerator that circulates and supplies cold water to a load, and uses water as a refrigerant and an aqueous lithium bromide (LiBr) solution as an absorption liquid.
[0008]
In the figure, 1 is a high temperature regenerator equipped with a gas burner 1A, 2 is a low temperature regenerator, 3 is a condenser, 4 is an evaporator, 5 is an absorber, 6 is a low temperature heat exchanger, 7 is a high temperature heat exchanger, 8 10 to 10 are absorption liquid pipes, 11 are absorption liquid pumps, 12 to 15 are refrigerant pipes, 16 are refrigerant pumps, 17 are open / close valves, 18 are cold water pipes through which cold water to be circulated and supplied to a cooling load (not shown), and 19 is a cold water pump. , 20 is a cooling water pipe, and 21 is a cooling water pump. These devices are connected by piping as shown in FIG. 1, and this configuration itself is well known in the art.
[0009]
And in the double effect absorption refrigerator of the said structure, when the on-off valve 17 is closed, cooling water is poured into the cooling water pipe 20, the gas burner 1A is ignited and the rare absorbent is heated by the high temperature regenerator 1, and the rare absorbent is Evaporated and separated refrigerant vapor and an intermediate absorption liquid in which the concentration of the absorption liquid is increased by separating the refrigerant vapor are obtained.
[0010]
The high-temperature refrigerant vapor generated in the high-temperature regenerator 1 enters the low-temperature regenerator 2 through the refrigerant pipe 12, and is generated in the high-temperature regenerator 1 through the high-temperature heat exchanger 7 via the high-temperature heat exchanger 7. The intermediate absorption liquid that has entered the condenser 2 is heated and condensed by heat dissipation, and enters the condenser 3.
[0011]
Further, the refrigerant heated by the low-temperature regenerator 2 and evaporated and separated from the intermediate absorption liquid enters the condenser 3, exchanges heat with the water flowing in the cooling water pipe 20 to be condensed and liquefied, and is condensed and supplied from the refrigerant pipe 12. The refrigerant enters the evaporator 4 through the refrigerant pipe 13 together with the refrigerant.
[0012]
The refrigerant liquid that has entered the evaporator 4 and accumulated in the refrigerant liquid reservoir is sprayed by the refrigerant pump 16 on the heat transfer pipe 18 </ b> A connected to the cold water pipe 18, and exchanges heat with water supplied through the cold water pipe 18. The water flowing through the heat transfer tube 18A is cooled.
[0013]
Then, the refrigerant evaporated in the evaporator 4 enters the absorber 5 and is heated in the low-temperature regenerator 2 to evaporate and separate the refrigerant, so that the absorption liquid having a further increased concentration of the absorption liquid, that is, the low-temperature heat exchange by the absorption liquid pipe 10. It is supplied via the vessel 6 and absorbed by the concentrated absorbent dispersed from above.
[0014]
Absorbing liquid having a reduced concentration due to absorption of the refrigerant by the absorber 5, that is, the rare absorbing liquid, is supplied to the high temperature regenerator 1 via the low temperature heat exchanger 6 and the high temperature heat exchanger 7 by the operation of the absorption liquid pump 11. It is sent from the absorption liquid pipe 8.
[0015]
When the absorption refrigerator is operated as described above, the cold water cooled by the heat of vaporization of the refrigerant in the heat transfer pipe 18A piped inside the evaporator 4 is passed through the cold water pipe 18 by the operation of the cold water pump 19. It is circulated and supplied to a cooling load (not shown) and performs a cooling action.
[0016]
C is a controller provided in the dual-effect absorption refrigerator having the above-described operation function, and includes a microcomputer, a storage means, and the like, and a chilled water pipe for circulating and supplying chilled water to a cooling load (not shown) 18, the temperature information of the cold water flowing out from the heat transfer pipe 18A of the evaporator 4 is taken in from the temperature sensor 22 provided on the outlet side of the evaporator 4 of the cold water pipe 18, and the evaporator outlet side temperature of this cold water becomes a predetermined set temperature. A conventionally known capacity control function for controlling the amount of heat input to the high-temperature regenerator 1 by adjusting the opening of a heating amount control valve (not shown) connected to the gas burner 1A so as to be maintained.
[0017]
That is, the controller C increases the degree of opening of the heating amount control valve connected to the gas burner 1A as the difference between the predetermined set temperature and the temperature of the cold water detected by the temperature sensor 22 increases. When the temperature of the chilled water detected by the sensor 22 reaches the set temperature, a control program for performing normal capacity control such as suppressing or closing the heating amount control valve to the set opening is stored in the storage means. I have.
[0018]
Further, the controller C controls the operation of the absorption liquid pump 11 so that the liquid level of the absorption liquid in the high temperature regenerator 1 is maintained at a predetermined level, and the temperature of the cold water detected by the temperature sensor 22 is the set temperature. The storage unit also includes a control program for operating the refrigerant pump 16 when the temperature is higher (for example, 7 ° C.).
[0019]
Further, the controller C starts the chilled water pump 19 by delaying the ignition / combustion of the gas burner 1A based on the pressure P in the vapor phase inside the evaporator 4 detected by the pressure sensor 23 attached to the evaporator 4. The control program shown in FIG. 2 is also provided in the storage means.
[0020]
That is, when a start switch (not shown) is turned on, the controller C outputs a required control signal to the cooling water pump 21 in step S1 and starts it, and in step S2, the controller C controls the absorption liquid pump 11 as required. A signal is output and activated, and in step S3, a required control signal is output to the gas burner 1A to start ignition and combustion.
[0021]
In step S <b> 4, the pressure sensor 23 detects the pressure P in the gas phase in the evaporator 4.
[0022]
In step S5, it is determined whether or not the pressure P detected in step S4 is a pressure at which the refrigerant liquid easily evaporates, for example, 1400 Pa or less. If it is determined that the pressure P is 1400 Pa or less, a step is performed. The process proceeds to S6, the cold water pump 19 is started, and when it is determined that it is not, the process returns to step S4 and the detection of the pressure P is repeated.
[0023]
In step S <b> 7, the flow rate V of chilled water supplied to the cooling load (not shown) by the chilled water pump 19 is detected by the flow rate sensor 24 attached to the chilled water pipe 18.
[0024]
In step S8, it is determined whether or not the chilled water flow rate V is greater than or equal to a predetermined flow rate α. If it is determined as YES, a required control signal is output to the refrigerant pump 16 to start it. If not, step S10 is performed. The pressure P is detected by the pressure sensor 23.
[0025]
In step S11, it is determined whether or not the pressure P detected in step S10 is 700 Pa or more. If it is determined as YES, the process returns to step S7 to repeatedly detect the cold water flow rate V. The cooling water pump 21, the absorption liquid pump 11, the cold water pump 19, the gas burner 1A, etc. are urgently stopped, and an alarm is issued by a buzzer sounding, a light turning on / flashing, or the like.
[0026]
Therefore, according to the present invention, the operation of the chilled water pump 19 is started after waiting for the pressure inside the evaporator 4 to drop to a pressure at which the refrigerant evaporates easily, and it is confirmed that the flow rate of the chilled water is ensured. As soon as the operation of the refrigerant pump 16 is started, the water inside the heat transfer pipe 18A is quickly cooled, and this is supplied to the cooling load by the cold water pump 19, so that the cooling operation can be quickly started up. It becomes possible.
[0027]
Further, when the operation of the cold water pump 19 is started, when the pressure P inside the evaporated gas drops below the set pressure, the refrigerant pump 16 is not started and the operation of the entire refrigerator is stopped. The water flowing through the inside and the coolant water will not freeze.
[0028]
The controller C is supplied from the condenser 3 by the refrigerant pipe 13 instead of waiting for the pressure P detected by the pressure sensor 23 to be equal to or lower than the set pressure, and proceeds to step S6. The temperature of the flushing refrigerant is detected by the temperature sensor 25, and the process waits for the temperature to become a set temperature, for example, 15 ° C. or less, and the process proceeds to step S6. The temperature of the concentrated absorbent supplied to the absorber 5 is detected by the temperature sensor 26, and the temperature shows a predetermined rise, for example, 5 ° C./minute, and waits for the circulation of the concentrated absorbent to be confirmed. Even if the process proceeds to step S6, the same effect as described above can be obtained.
[0029]
Moreover, as the controller C, steps S10 and S11 can be similarly changed. In this case, in steps S4 and S5 and steps S10 and S11, it is advantageous to detect and determine the same physical quantity, so that the attached sensor can be shared, but in steps S4 and S5 and steps S10 and S11. In different physical quantities, that is, in steps S4 and S5, for example, the pressure P inside the evaporator 4 is detected and determined, and in steps S10 and S11, the temperature is detected by the temperature sensor 25 or 26 and determined based on the temperature. You may comprise.
[0030]
Further, the controller C can be configured to make an emergency stop when the control between steps S7 and S11 is repeated over a predetermined time.
[0031]
Further, the control method of the present invention pipes so that the high-temperature refrigerant vapor and the absorption liquid generated by heating in the high-temperature regenerator 1 can be directly supplied to the absorber 5 or the evaporator 4, and the heat transfer tube of the evaporator 4. An absorption chiller / heater that can heat and supply water flowing through the interior of 18A is also effective.
[0032]
【The invention's effect】
As described above, according to the present invention, it is possible to start the operation of the chilled water pump after waiting for the refrigerant to be easily evaporated in the evaporator, and cooling is performed by performing such control. The disadvantages of the prior art, such as the fact that no water is supplied to the cooling load and the temperature inside the system is raised to lengthen the startup time of the cooling, are eliminated, and the cold water quickly obtained by the heat transfer tubes of the evaporator is used as the cooling load. By supplying, cooling operation can be started up in a short time.
[0033]
In addition, even if the operation of the cold water pump is started, the refrigerant pump does not start when the refrigerant becomes apt to evaporate abnormally, such as when the inside of the vapor shows a pressure drop exceeding the set value. Therefore, the water flowing in the heat transfer tube and the coolant water are not frozen and the safety is excellent.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an apparatus configuration.
FIG. 2 is an explanatory diagram of a control method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 High temperature regenerator 1A Gas burner 2 Low temperature regenerator 3 Condenser 4 Evaporator 5 Absorber 6 Low temperature heat exchanger 7 High temperature heat exchanger 8-10 Absorption liquid pipe 11 Absorption liquid pump 12-15 Refrigerant pipe 16 Refrigerant pump 17 On-off valve 18 Chilled water pipe 19 Chilled water pump 20 Chilled water pipe 21 Chilled water pump 22 Temperature sensor 23 Pressure sensor 24 Flow rate sensor 25/26 Temperature sensor C Controller

Claims (2)

The refrigerating machine, the condenser, the absorber, etc. and the heat transfer pipes piped inside the evaporator that constitutes the refrigeration cycle supply the cooled fluid to the cooled part by taking the heat of evaporation from the refrigerant and performing the cooling action At the start of the absorption refrigerator, heating of the absorption liquid in the regenerator and the supply of cooling water to the absorber and the condenser are started in advance, and then the internal pressure of the evaporator and / or the absorber, from the condenser Based on at least one of the temperature of the refrigerant supplied and flushed by the evaporator and the temperature of the absorbing liquid supplied from the regenerator to the absorber, an operation of the pump for supplying the fluid to the cooled part is performed. A control method for an absorption refrigeration machine, which starts and starts operation of a refrigerant pump for spraying the refrigerant liquid supplied from the condenser and accumulated in the refrigerant liquid reservoir to the heat transfer pipe. When the operation of the pump that supplies the fluid to the cooled part is started, the inside of the evaporator and / or the absorber shows a pressure drop exceeding the set value, or is supplied from the condenser and flushed by the evaporator. The absorption chiller is operated without starting the operation of the refrigerant pump when the refrigerant being cooled shows a temperature drop exceeding the set value or the absorption liquid supplied from the regenerator to the absorber shows a temperature rise exceeding the set value. The method for controlling an absorption refrigerator according to claim 1, wherein:

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