JPH0478903B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dual-effect absorption refrigerator having a control device for operating during shutdown.

[Conventional technology]

In conventional absorption chillers, when the operation is stopped,
To prevent solution crystallization, the solution pump continues to operate even after the control valve of the generator heating source is closed and the refrigerator operation is stopped, performing dilution operation to equalize the concentration in the solution path. However, the cooling water pump continued to operate along with the solution pump, and stopped when the solution pump stopped.

[Problem that the invention seeks to solve]

However, usually the output of the solution pump (for example, 1
The output of the cooling water pump was large (for example, 6 to 10 kW) compared to the conventional cooling water pump (6 to 10 kW), and operating the cooling water pump more than necessary resulted in a loss of power.

In addition, if the cooling water is passed more than necessary, the internal pressure of the high temperature generator decreases, making it difficult to circulate the solution, and there is a risk that the concentration will not be sufficiently uniform, leading to crystal formation.

To avoid such problems, if you stop the cooling water pump immediately when the refrigerator stops, the uncooled spray solution that remains at a high temperature will fall, increasing the temperature of the cooling water in the cooling water tube, and causing The excessive stress caused damage to the tubes and damaged the plastic filling in the cooling tower during restart.

The present invention solves the above-mentioned problems of the conventional ones, reduces power loss, promotes solution dilution,
It is an object of the present invention to provide a dual-effect absorption refrigerating machine that prevents damage to the tubes due to thermal stress and does not damage the filling material in the cooling tower when restarted.

[Means for solving problems]

The present invention provides an evaporator, an absorber, a high temperature generator, a low temperature generator, a condenser, a solution path connecting these devices,
A refrigerant path, a solution pump provided in these paths, a refrigerant pump, a cooling water path communicating with the absorber and the condenser, a cooling water pump provided in the cooling water path, and a cold water communicating with the evaporator. A dual-effect absorption refrigeration system, comprising: a cooling water route, a cold water pump installed in the cold water route, and a timer mechanism that issues a signal to stop the operation of the cooling water pump after a predetermined set time after the chiller operation has stopped. In the refrigerator, when the load is large according to a load detector that detects the load condition before the chiller stops operating, and the load condition detected by the load detector during operation before the chiller stops operating. The device is equipped with a control mechanism that selects a predetermined set time so that the time is long and the time is short when the load is small.

[Effect]

According to the present invention, when the absorption refrigerating machine is stopped, the cooling water pump is not immediately stopped, but is allowed to continue operating for a while depending on the load condition before stopping, thereby continuing to circulate the cooling water. The solution pump continues to operate for dilution, and the solution is circulated, but since heating in the generator has already been stopped, it is cooled by the cooling water, and the solution temperature gradually decreases, and the cooling water temperature also decreases. It gradually decreases.

The filling material used in cooling towers is, for example, hard vinyl chloride (PVC), and its practical heat resistance limit is approximately 60 to 80°C.

Therefore, after the refrigerator stops operating, the temperature of the cooling water gradually decreases, and the cooling water in the cooling water tube, which stops flowing and becomes stagnant, becomes a relatively high temperature solution (already to some extent). The cooling water pump should be stopped when the temperature drops (for example, 25 to 30 degrees Celsius) or below, which does not reach the above heat resistance limit. , relates to the state of the load at or just before the stop.

That is, if the operation is under high load at the time of shutdown, the pressure inside the generator is high and the solution temperature is also high, so the temperature of the solution returned to the absorber is also high, and the cooling water after the shutdown is The rate of temperature drop also slows down. Therefore, the time required for the cooling water temperature to drop to a predetermined allowable temperature after the refrigerator stops operating is long after high-load operation, and short after low-load operation.

The load condition at or just before the stoppage (the time just before or the average from about 10 minutes before the stoppage until the stoppage) is detected by the temperature of the solution, etc., and the cooling water is turned on after a predetermined set time after the stoppage. A timer mechanism is provided to stop the pump, and the set time of this timer mechanism is selected according to the load condition detected in advance.
To stop a cooling water pump after a point in time when the cooling water temperature should become below a predetermined allowable temperature.

In the present invention, the setting time of the timer mechanism is selected according to the load condition at or before the time of stopping, that is, the setting time is set longer after high-load operation and shorter after low-load operation, and the cooling water pump is activated. By stopping the cooling water, even if a relatively high-temperature solution (the temperature has already dropped to a certain extent) falls after the cooling water flow has stopped, the cooling water remaining in the tube will still reach the above-mentioned limit. temperature of 60 to 80℃, which prevents damage caused by thermal expansion of the tube, and even if the chiller is restarted afterwards, cooling water that has reached a sufficiently low temperature is sent to the cooling tower to prevent damage to the filling material. Never.
Moreover, there is no need to operate the cooling water pump for an unnecessarily long period of time, resulting in loss of power, or to reduce the internal pressure of the high-temperature generator too much, thereby interfering with the dilution operation.

In addition, as a load detector to detect the load condition,
When using a temperature detector to detect the temperature of the solution, be sure to use a temperature sensor that detects the temperature of the solution at a high-temperature, high-pressure part (a part where the pressure is higher than that of the low-temperature generator GL, such as the inside of the high-temperature generator GH, the outlet of the high-temperature generator GH, etc.). ) is preferably detected. Other load detectors that detect the heating amount of the high-temperature generator GH include a flow rate detector for the heating source fluid (steam, hot water, or fuel gas or fuel oil in the case of a direct-fired type), or a flow rate detector for the flow rate control valve. An opening detector may also be used. Further, as the load detector, a pressure detector or a temperature detector that detects the pressure or saturation temperature within the high temperature generator GH may be used. Furthermore, a temperature detector that detects the cooling water temperature related to the above temperature and pressure may be used.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

In Figure 1, A is an absorber, E is an evaporator, and GH
is a high temperature generator, GL is a low temperature generator, C is a condenser,
XH is a high temperature solution heat exchanger, XL is a low temperature solution heat exchanger, SP is a solution pump, RP is a refrigerant pump, and V is a pressure reducing valve.

Solution paths 3, 4, and 5 and refrigerant paths 6, 7, and 8 are connected between these devices, and the absorption solution and refrigerant are circulated.

Reference numeral 1 denotes a heat source path through which a heat source fluid such as steam flows, and a flow rate control valve 2 controls the flow rate of the heat source fluid to control the capacity of the absorption refrigerator.

Reference numeral 9 denotes a cold water path, in which cold water is circulated between the load 10 and the evaporator E by a cold water pump 11.

12 is a cooling water path, in which cooling water is circulated through a cooling tower 14, an absorber A, and a condenser C by a cooling water pump 13.

Reference numeral 15 denotes a capacity control device which receives a cold water temperature signal from a temperature detector 16 that detects the cold water outlet temperature and operates the flow rate control valve 2 so that the cold water temperature is constant.

Reference numeral 18 denotes a control device, which is configured to issue a signal to stop the cooling water pump 13 after a set time period given by the timer mechanism 22 has elapsed since the operation of the refrigerator was stopped. Thus, the set time in the timer mechanism 22 is selected depending on the solution temperature at or just before the operation is stopped, which is detected by the temperature detector 23 which is a load detector and which detects the solution temperature in the high temperature generator CH.

As the load detector, a temperature detector 21 that detects the solution temperature at the outlet of the high temperature generator GH may be used, and a flow rate detector that detects the flow rate of the heating source fluid to detect the load based on the amount of heating. and an opening degree detector 24 that detects the opening degree of the flow rate control valve 2.
The pressure detector 25 that detects the internal pressure of the high temperature generator GH may be used, or the temperature sensor that detects the cooling water temperature related to these temperatures and pressures may be used.

FIG. 2 is a flowchart when the operation is stopped.

〔Effect of the invention〕

The present invention includes a load detector that detects the load state of the refrigerator before the operation of the refrigerator is stopped, and a load that is large depending on the load state during the operation of the refrigerator before the operation of the refrigerator is stopped, which is detected by the load detector. Equipped with a control mechanism that selects a predetermined set time such that the time is longer when the load is low and the time is shorter when the load is light, ensuring proper stopping of the cooling water pump and stopping the operation of the absorption chiller. In addition to preventing wasteful loss of power associated with this, it also promotes dilution of the solution, prevents damage to the cooling water tube of the absorber due to thermal stress, and eliminates the risk of damaging the cooling tower packing material upon restart. It is possible to provide a heavy-duty absorption refrigerating machine, which has extremely great practical effects.

[Brief explanation of drawings]

FIG. 1 is a flowchart of an embodiment of the present invention, and FIG. 2 is a flowchart thereof. 1... Heat source path, 2... Flow rate control valve, 3...
Solution route, 4... Solution route, 5... Solution route, 6
... Refrigerant route, 7... Refrigerant route, 8... Refrigerant route, 9... Chilled water route, 10... Load, 11... Chilled water pump, 12... Cooling water route, 13... Cooling water pump, 14... ... Cooling tower, 15 ... Capacity control device, 16 ... Temperature detector, 18 ... Control device, 2
1... Temperature detector, 22... Time limit mechanism, 23...
Temperature detector, 24... Opening degree detector, 25... Pressure detector, A... Absorber, E... Evaporator, GH...
High temperature generator, GL...Low temperature generator, C...Condenser,
XH……High temperature heat exchanger, XL……Low temperature heat exchanger,
SP...Solution pump, RP...Refrigerant pump, V...
Pressure reducing valve.

Claims (1)

[Claims] 1 Evaporator, absorber, high temperature generator, low temperature generator,
A condenser, a solution path connecting these devices, a refrigerant path, a solution pump provided in these paths, a refrigerant pump, a cooling water path leading to the absorber and the condenser, and a cooling water path provided in the cooling water path. A cooling water pump, a cold water path leading to the evaporator, and a cold water pump installed in the cold water path, and transmitting a signal to stop the operation of the cooling water pump after a predetermined set time after stopping the operation of the refrigerator. A load detector for detecting a load condition before the operation of the refrigerator stops;
The predetermined set time is set so that the time is longer when the load is large and the time is shorter when the load is small, depending on the load condition during operation of the chiller detected by the load detector before the refrigerator stops operating. A dual-effect absorption chiller characterized by comprising a selectable control mechanism.