JP2979370B2 - Control method of absorption chiller / heater with cooling / heating switching function - 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 chiller / heater,
In particular, the present invention relates to a method for controlling an absorption chiller / heater with a cooling / heating switching function.

[0002]

2. Description of the Related Art Conventionally, there is known a double effect absorption chiller / heater having a cooling / heating switching function as shown in FIG. The illustrated absorption chiller / heater is provided with a high-temperature regenerator 2 for heating a dilute solution by a burner 3, a separator 5 connected to the high-temperature regenerator 2 by a liquid pump 4, and a separator 5 in contact with the separator 5. Low-temperature regenerator 7 equipped with a refrigerant vapor pipe through which refrigerant vapor separated by separator 5 flows
A high-temperature solution heat exchanger 6 in which the intermediate concentrated solution separated by the separator 5 flows on the heating fluid side, and a low-temperature solution heat exchanger 15 in which the concentrated solution generated by the low-temperature regenerator 7 flows on the heating fluid side.
And a condenser cooling coil 1 disposed adjacent to the low-temperature regenerator 7 and communicated with the low-temperature regenerator 7 through a refrigerant vapor flow path.
9; an evaporator 9 disposed adjacent to the condenser 8 and including a cold / hot water coil 10;
Condenser cooling coil 19 disposed adjacent to and in communication with
, A cooling / heating switching valve 2 serving as cooling / heating switching means interposed in a pipe connecting the separator 5 and the absorber 14.
3, a concentrated solution pipe 24 for guiding the concentrated solution passing through the heated fluid side of the low-temperature solution heat exchanger 15 to a concentrated solution distribution pipe 16 provided in the absorber, and a cold and hot water circulating through the cold and hot water coil 10. A water pump 41; a control box 40 for controlling the cold / hot water pump 41 and the burner 3;
A solution circulating pump 21 having a suction side connected to the bottom portion of the low temperature solution heat exchanger 15 via a dilute solution pipe 22 and a discharge side connected to the fluid to be heated side of the low temperature solution heat exchanger 15; A gas separator 30 connected to a gas inlet pipe 34 in which a gas outlet is located, and a gas downcomer 3
5, a solution return pipe 37 communicating the bottom of the gas separator B36 with the bottom 43 of the evaporator 9, the concentrated solution pipe 24 and the gas separator 3
0, a concentrated solution introducing pipe 32 communicating with the bottom of the gas separator B 36, a gas storage chamber 42 connected to the upper part of the gas separator B 36 by a gas separating pipe 38, and a cooling water pipe connected to one end of the absorber cooling coil 17. 20A, a cooling water pipe 20 connected to one end of the condenser cooling coil 19, a conduit 45 connecting the cooling water pipe 20 and the gas separator 30, and a conduit 45A connecting the cooling water pipe 20A and the gas separator 30. , Is configured. The evaporator 9 is provided with a refrigerant distribution pipe 11 for dispersing the liquid refrigerant generated by condensing and liquefying the refrigerant vapor flowing into the condenser 8 onto the cold / hot water coil 10. The cooling water flowing into the gas separator 30 from the conduit 45A flows through the cooling coil in the gas separator 30 to the conduit 45, and the cooling water piping 20
Into the cooling water flowing through.

[0003] In the apparatus having the above configuration, during the heating operation,
The cooling / heating switching valve 23 is opened, and the high-temperature solution and the high-temperature refrigerant vapor generated in the high-temperature regenerator 2 are guided to the evaporator 9 through the absorber 14, and the high-temperature solution is stored in the bottom 43 of the evaporator 9. Since the pressure in the evaporator 9 increases and becomes equal to or higher than the pressure of the gas storage chamber 42, the high-temperature solution stored in the bottom 43 of the evaporator 9 enters the solution return pipe 37, passes through the gas separator B36, and It rises in the gas separation tube 38 until balance is achieved.

[0004]

When the heating is stopped,
According to the control flow shown in FIG. 2, a stop command is issued from the control box 40 to the burner 3 and the cold / hot water pump 41 at the same time. However, with such a mechanism, when heating is stopped, the evaporator 9
Since the internal pressure temporarily increases due to residual heat from the surroundings, the high-temperature solution is further sent into the solution return pipe 37. After a lapse of a certain period of time thereafter (when switching from heating to cooling, the cooling operation is started after a lapse of about 30 minutes after stopping heating in consideration of the temperature of the apparatus). When the cooling water starts, the cooling water flows through the cooling water pipe 20, and the pressure in the evaporator 9 rapidly decreases. Due to this rapid decrease in pressure, the high-temperature solution in the solution return pipe 37 flashes and runs out of liquid, so the U-shaped liquid seal maintained by the solution in the solution return pipe 37 and the gas in the gas separation pipe 38 is broken, and The non-condensable gas sealed in the storage room 42 flows back into the evaporator 9. When the non-condensable gas flows back into the evaporator 9, the pressure in the evaporator 9 does not decrease to a required pressure, and a cooling capacity defect occurs.

SUMMARY OF THE INVENTION An object of the present invention is to provide an absorption chiller / heater which can remotely switch between a heating operation and a cooling operation by operating a cooling / heating switching valve as described above. The purpose is to prevent

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a high-temperature regenerator having a burner for heating an absorbing solution, and a method for refrigerating a refrigerant from the absorbing solution heated by the high-temperature regenerator. A separator that separates the vapor and the intermediate concentrated solution, a condenser that condenses and liquefies the refrigerant vapor separated by the separator, and an evaporator that cools the cold and hot water by evaporating the liquid refrigerant generated by the condenser. A hot / cold water pump for circulating cold / hot water through the evaporator, a gas storage chamber connected to the bottom of the evaporator via a solution return pipe to store non-condensable gas, and a means for switching between the separator and the evaporator. A pipe that communicates through a valve that forms
In the operation method of the absorption chiller / heater with the cooling / heating switching function including the above, when the heating operation is stopped to switch from the heating operation to the cooling operation, first, the combustion of the high temperature regenerator heating burner is stopped, and the combustion of the burner is stopped. The operation of the cold / hot water pump is continued until the residual heat in the heating state around the post-evaporator is removed.

[0007]

The operation of the chilled / hot water pump is continued until the residual heat in the heating state around the evaporator is removed even after the combustion of the burner is stopped. Since the water is removed by the hot and cold water circulating in the water coil, the pressure inside the evaporator is prevented from rising due to the surrounding residual heat after the heating operation is stopped, and the solution remaining at the bottom of the evaporator is removed after the heating operation is stopped. No more getting into the return pipe. In addition, the temperature of the solution remaining at the bottom of the evaporator decreases as the residual heat in the heating state around the evaporator is removed by the cold and hot water circulating in the cold and hot water coil provided in the evaporator. Therefore, even if the pressure of the evaporator suddenly drops at the start of the cooling operation, the solution in the solution return pipe, which seals the space between the evaporator and the gas storage chamber, flashes, and the liquid disappears and the seal is broken. Disappears.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The configuration of the absorption chiller / heater is the same as that described above as the prior art. Therefore, as described above, during the heating operation, the high temperature solution at the bottom 43 of the evaporator 9 enters the solution return pipe 37 and rises the gas separation pipe 38 to form a U-shaped liquid seal. The U-shaped liquid seal differential pressure is determined by the pressure of the evaporator 9 and the pressure of the gas storage chamber 42. During heating,
Evaporator pressure> gas storage chamber pressure.

When heating is stopped from the heating operation state, the burner 3 is immediately stopped in accordance with the control flow shown in FIG. 1, but the chilled / hot water pump 41 is activated after the burner is stopped and the residual heat in the heating state around the evaporator. After the operation is continued until is removed, the operation is stopped. Therefore, the residual heat around the evaporator at the time of stopping the burner is removed by the cold / hot water circulating in the cold / hot water coil 10, and the pressure of the evaporator does not increase due to the residual heat. Since no pressure rise occurs, no hot solution at the bottom 43 of the evaporator 9 enters the solution return pipe 37. Evaporator 9
The high-temperature solution in the bottom portion 43 is driven by the cold / hot water pump 41 to remove a part of the heat as the heat around the evaporator is removed by the cold / hot water circulating through the cold / hot water coil 10, and the solution return pipe The solution in 37 is also gradually cooled during the switching waiting time of 30 minutes. After the elapse of 30 minutes, when the cooling operation is started, the pressure in the evaporator also decreases rapidly, but the solution at the bottom 43 of the evaporator 9 is not flushed because its temperature has dropped, and the solution in the solution return pipe 37 is not flushed. The solution does not run out by flushing, and the U-shaped liquid seal is not broken. Naturally, backflow of the non-condensable gas sealed in the gas storage chamber 42 to the evaporator does not occur, so that the presence of the non-condensable gas in the evaporator can be prevented from lowering the cooling capacity. According to the experiments by the inventors, after the combustion of the burner 3 is stopped, the evaporator is cooled by operating the cold / hot water pump 41 for at least 10 minutes until the residual heat in the heating state around the evaporator is removed. At the start of operation, the solution return pipe 3
The flushing of the solution in 7 can avoid breaking the U-shaped liquid seal.

During cooling, the cooling / heating switching valve 23 is closed, a part of the concentrated solution that has released heat in the low-temperature solution heat exchanger 15 is branched off from the concentrated solution pipe 24, and passes through the concentrated solution introduction pipe 32 to the gas separator. It is led to 30. The concentrated solution guided to the gas separator 30 is cooled by cooling water flowing through a cooling coil in the gas separator 30. The pressure of the gas separator 30 is controlled by the absorber 14
And the non-condensable gas in the vicinity of the absorber cooling coil 17 is sucked up through the gas introduction pipe 34 and guided to the gas separator 30. The non-condensable gas accumulated in the gas separator 30 falls down the gas down pipe 35 together with the concentrated solution,
Enter the gas separator B36. The non-condensable gas is separated here, guided to a gas storage chamber 42 by a gas separation pipe 38, and stored. Further, the solution in the gas separator B 36 is returned to the bottom 43 of the evaporator 9 via the solution return pipe 37. Due to the gas pressure of the non-condensable gas stored in the gas storage chamber 42, the evaporator pressure <the gas storage chamber pressure. However, the solution in the solution return pipe 37 and the gas separation pipe 38 seals the U-shaped liquid. Therefore, the non-condensable gas does not flow back to the evaporator 9 side.

[0012]

According to the present invention, even if the cooling / heating switching operation is performed arbitrarily, the non-condensable gas stored in the gas storage chamber does not enter the evaporator side, so that the non-condensable gas absorption capacity is improved. There is no decrease in cooling capacity due to inhibition.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of the related art.

FIG. 3 is a block diagram showing an example of a configuration of an absorption chiller / heater to which the present invention is applied.

[Explanation of symbols]

2 High temperature regenerator 3 Burner 4 Pumping pipe 5 Separator 6 High temperature solution heat exchanger 7 Low temperature regenerator 8 Condenser 9 Evaporator 10 Cold and hot water coil 11 Refrigerant distribution pipe 14 Absorber 15 Low temperature solution heat exchanger 16 Concentrated solution Piping 17 Absorber cooling coil 19 Condenser cooling coil 20, 20A
Cooling water pipe 21 Solution circulation pump 22 Dilute solution pipe 23 Cooling / heating switching valve 24 Concentrated solution pipe 30 Gas separator 32 Concentrated solution introduction pipe 34 Gas introduction pipe 35 Gas descending pipe 36 Gas separator B 37 Solution return pipe 38 Gas separation pipe 40 Control box 41 Cold / hot water pump 42 Gas storage room 43 Bottom part of evaporator 9 45, 45A
conduit

Claims (1)

(57) [Claims] 1. A high-temperature regenerator having a burner for heating an absorption solution, a separator for separating refrigerant vapor and an intermediate concentrated solution from the absorption solution heated by the high-temperature regenerator, and a separator for the separation A condenser for condensing and liquefying the refrigerant vapor, an evaporator for evaporating the liquid refrigerant generated in the condenser to cool the hot and cold water, a cold and hot water pump for circulating the cold and hot water through the evaporator, and a bottom of the evaporator. A gas storage chamber that is connected via a solution return pipe to store non-condensable gas, and a pipe that communicates the separator with the evaporator via a valve that forms a cooling / heating switching unit,
In the operation method of the absorption chiller / heater with the cooling / heating switching function including the above, when the heating operation is stopped to switch from the heating operation to the cooling operation, first, the combustion of the high temperature regenerator heating burner is stopped, and the combustion of the burner is stopped. A method for controlling an absorption chiller / heater with a cooling / heating switching function, wherein the operation of the chill / hot water pump is continued until residual heat in a heating state around the post-evaporator is removed.