JPH0447227B2 - - 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 2 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 problems such as tube damage and damage to 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 as a means for solving the above problems,
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 chiller including a cooling water path and a chilled water pump provided in the chilled water path, comprising: a cooling water temperature detector that directly or indirectly detects the temperature of the cooling water in the cooling water path; When the cooling water temperature or the equivalent value of the cooling water temperature detected by the detector becomes equal to or less than a predetermined set value after the operation of the absorption chiller is stopped, a stop signal is generated to stop the cooling water pump in response to the signal. It is an object of the present invention to provide a dual-effect absorption refrigerating machine characterized by being equipped with a control device for generating heat.

[Effect]

According to the present invention, when the absorption refrigerating machine is stopped, the cooling water pump is not stopped immediately but is allowed to continue operating for a while, so that the cooling water continues to be circulated. The solution pump continues to operate for dilution, and the solution is being circulated, but since heating in the generator has already been stopped, the solution temperature gradually decreases as it is cooled by the cooling water, 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.
The present invention detects the decreasing cooling water temperature at the condensing outlet after the refrigerator is stopped, and sets it to a predetermined value, for example, 20 to 30°C, which is below the heat resistance limit of the material used.
When the temperature drops below the set value within the range, the control device receives this signal and issues a stop signal to stop the cooling water pump. Even if a solution at an extremely high temperature is sprayed, the temperature does not reach that high, and the temperature of the solution itself has dropped considerably, so the temperature of the cooling water will not rise to the above-mentioned heat resistance limit. Therefore, even if the refrigerator is restarted after that, the cooling water that has reached a sufficiently low temperature is sent to the cooling tower, so that the filling material will not be damaged. In addition, the cooling water tube is designed with temperatures up to about 60°C in mind, so it will not be damaged by thermal stress.
Furthermore, 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.

Note that it is most preferable to detect the temperature of the cooling water at the outlet of the condenser because the result including all the load conditions can be detected, but it may also be detected at the inlet of the absorber.

In addition, instead of directly detecting the temperature of the cooling water itself, the temperature of something related to the cooling water temperature is indirectly detected as a cooling water temperature equivalent value, which corresponds to the allowable value of the cooling water temperature. The control device may issue a stop signal for the cooling water pump when the temperature falls below a set value.

For example, since the temperature of the solution in the return path from the high-temperature generator has a close relationship with the temperature of the cooling water, the solution temperature at the inlet returning to the absorber, the solution temperature at the exit from the generator, etc. may be detected. . The set temperature is 30~30 for the absorber inlet temperature.
110 for a temperature around 40℃, generator outlet temperature
A temperature of ~130°C is selected.

In addition, the temperature inside the absorber or condenser as a heat exchanger through which the cooling water passes is also closely related to the temperature of the cooling water, so the temperature of the solution inside the absorber, the refrigerant vapor temperature, the refrigerant vapor temperature inside the condenser, The refrigerant liquid temperature may also be detected. As the set temperature, a temperature of about 25 to 30°C is selected for the temperature inside the absorber, and a temperature of about 25 to 30°C is selected for the temperature inside the condenser.

〔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 17 denotes a temperature detector that detects the temperature of the cooling water at the outlet of the condenser C, and when the detected temperature falls below a predetermined set value, the control device 18 that receives the signal issues a stop signal to stop the cooling water pump 13. It's starting to stop.

Instead of detecting the coolant outlet temperature, a temperature detector 19 that detects the coolant inlet temperature may be used. In addition, as the temperature of the returned solution, which is closely related to the cooling water temperature, a temperature detector 20 that detects the inlet solution temperature of the absorber A or a temperature detector 21 that detects the outlet solution temperature of the high temperature generator GH is used. Good too. In addition, absorber A, which is closely related to cooling water temperature,
The internal temperature or the internal temperature of the condenser C may be detected.

Among the above, when the temperature of the cooling water is not detected directly but is detected indirectly using the temperature of something related to the temperature of the cooling water, the set value is as follows:
The temperature corresponding to the allowable temperature limit of the cooling water is set as the set value.

FIG. 2 shows an example of a flowchart when the refrigerator is stopped when the temperature detector 21 detects the outlet temperature of the high temperature generator GH as an example of indirectly detecting the cooling water temperature. An example is shown in which the set value is 120℃.

〔Effect of the invention〕

The present invention prevents wasteful power loss when shutting down an absorption chiller, promotes solution dilution, prevents damage to the cooling water tube of the absorber due to thermal stress, and fills the cooling tower when restarting. It is possible to provide a dual-effect refrigerator that does not cause damage to materials, which is extremely effective in practice.

[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, 17...Temperature detector,
18...control device, 19...temperature detector, 20...
...Temperature detector, 21...Temperature 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. In a dual-effect absorption refrigerator comprising a cooling water pump, a cold water path leading to the evaporator, and a cold water pump installed in the cold water path, the temperature of the cooling water in the cooling water path is directly or indirectly controlled. A cooling water temperature detector to detect, and a signal when the cooling water temperature or the equivalent value of the cooling water temperature detected by the cooling water temperature detector becomes less than a predetermined set value after the absorption chiller stops operating. and a control device that issues a stop signal to stop the cooling water pump in response to the above. 2. A patent claim in which the temperature of the cooling water is indirectly detected by detecting the temperature of the solution in the solution return path from the outlet of the high-temperature generator or the low-temperature generator to the absorber or in the absorber. The refrigerator according to item 1.