JPH08105661A - Absorption chilled and warm water generator and controlling method therefor - Google Patents

Abstract

PURPOSE: To provide an absorption chilled and warm water generator in which cooling operation is stabilized and which has maintenance conservation and a simple piping and a method for controlling the same. CONSTITUTION: A refrigerant self-purifying pipe 17 is connected to the discharge side of a refrigerant pump 9 via a valve 16 to always introduce liquid refrigerant to a condenser 13. At the time of stopping the operation, liquid refrigerant is introduced from the condenser 13 to an absorber 5 via an automatic valve 19 through a refrigerant blow tube 19. Thus, the liquid refrigerant fed to the condenser during the operating is automatically set to the absorber at the time of stopping to self-purify the liquid refrigerant.

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 and its control method, and more particularly to an absorption chiller-heater having a function of always keeping a refrigerant (water) in a high purity state and a control method thereof.

[0002]

2. Description of the Related Art FIG. 2 shows a cooling cycle of a conventional absorption chiller-heater, which includes an evaporator 1, an absorber 5 and a condenser 1.
3. It consists of seven heat exchangers, a high temperature regenerator 10, a low temperature regenerator 11, a high temperature heat exchanger 9 and a low temperature heat exchanger 8.
During the cooling operation of the absorption chiller-heater, the high temperature regenerator 10,
In the low temperature regenerator 11, the solution (aqueous solution of lithium bromide) is heated to generate the refrigerant vapor. In this process, the liquid extraction due to boiling of the solution may be mixed with the refrigerant vapor and flow into the evaporator 1 together with the low temperature regenerator 11 and the liquid refrigerant liquefied in the condenser 13. A small amount of mixed solution
Finally, it is accumulated together with the liquid refrigerant 4 in the evaporator 1. The liquid refrigerant 4 is evaporated and becomes a refrigerant vapor, flows into the absorber 5, and is absorbed by the highly hygroscopic solution scattered on the absorber 5. However, since the solution does not evaporate from the evaporator 1, the solution accumulates and the solution concentration of the liquid refrigerant 4 increases. The liquid refrigerant 4 containing a large amount of the solution has a reduced evaporating effect, lowers the refrigerating capacity, and accumulates in the evaporator 1 to raise the liquid refrigerant liquid level. If the operation is continued as it is, the concentration of the solution system increases, leading to overconcentration.

In order to solve these problems, of course, a solution is not mixed into the refrigerant system, but when mixed, the liquid refrigerant of reduced purity is directly introduced into the solution system absorber 5 to regenerate it at high temperature. It was necessary to re-refine the liquid refrigerant in the vessel 10 and the low temperature regenerator 11. For this purpose, a refrigerant refining pipe 15 for guiding the liquid refrigerant to the solution system from the discharge pipe of the refrigerant pump 2 via the partition valve 14 is provided.

The structure in which the refrigerant blow pipe 19 of FIG. 2 is installed was filed in Japanese Patent Application No. 5-490222 as a measure for suppressing the residual refrigerating capacity and preventing solution crystallization when the operation of the refrigerator is stopped. There is. Japanese Patent Laid-Open No. 5-60346 describes a structure having a blow pipe 19. this is,
As when the fan coil is stopped, the heat load of the refrigerator is sharply reduced, the water in the cold water heat transfer tube 21 is frozen due to the decrease in the refrigerant temperature of the evaporator 1, and the heat transfer tube may be damaged.
As a safe operation to prevent this, the automatic valve 18 of the refrigerant blow pipe 19 is opened to allow the liquid refrigerant to flow into the absorber 5 so as to dilute the absorption liquid, thereby suppressing the refrigerating capacity and crystallizing the solution. is there.

FIG. 3 shows another means for causing the liquid refrigerant to flow into the solution system. If the refrigerant tank and the solution tank are arranged next to each other and the partition between them is the weir 22 and the liquid refrigerant 4 overflows into the solution tank when the liquid refrigerant 4 exceeds a certain amount, the refrigerant refining as described above will be performed. Even if the pipe 15 and the gate valve 14 are not provided, the solution mixed in a small amount in the liquid refrigerant can flow into the solution system (absorber) without accumulating in the evaporator 1.

[0006]

In the conventional structure as shown in FIG. 2, each time the purity of the liquid refrigerant in the evaporator 1 decreases,
The liquid refrigerant must be allowed to flow into the solution system, but if the liquid refrigerant is introduced into the solution system all at once, the refrigerating capacity drops sharply, and it takes time until the refrigerating capacity is restored, which interferes with normal cooling operation. Therefore, it cannot be operated frequently. Also, the operation was done manually, or a separate automatic valve had to be installed. On the other hand, in the structure shown in FIG.
Since the liquid refrigerant 4 of No. 2 flows into the absorber 5, the solution in the absorber is diluted and the absorbing action is reduced, so that there is a problem that the refrigerating capacity is reduced. Further, since the solution is sprayed in the absorber 5, it is necessary to prevent the solution from scattering by the baffle plate 23 so that the droplets do not mix with the liquid refrigerant 4 of the evaporator 1. It is necessary to pass the refrigerant vapor from the evaporator 1 to the absorber 5, which requires a complicated wire mesh structure and is expensive.

An object of the present invention is to provide an absorption chiller-heater and a control method thereof, which has a simple structure, can automatically maintain the purity of the liquid refrigerant at a high value, and can prevent overconcentration of the solution system. There is.

[0008]

According to the present invention, a refrigerant self-cleaning pipe for branching a pipe from a refrigerant pump discharge pipe of an evaporator and guiding it to a condenser through an orifice or a regulating valve and a liquid refrigerant of the condenser are provided. Provided is an absorption chiller-heater equipped with a refrigerant blow pipe for guiding a liquid refrigerant from an accumulating tank to an absorber via an automatic valve, and the refrigerant self-cleaning pipe is a rising part that rises upward from the branch point. And a U-shaped portion having one end connected to the upper end of the rising portion and a connecting portion for guiding the other end of the U-shaped portion to the condenser, and the connecting point between the rising portion and the U-shaped portion. To provide an absorption chiller / hot water machine provided with a communication pipe for connecting the vapor phase part of the evaporator through an orifice or a regulating valve, and when the operation is stopped, the automatic valve is opened to send the liquid refrigerant to the absorber. Absorption chiller-heater equipped with control means for controlling Provided, further, when the liquid level detecting means for detecting the height of the liquid refrigerant liquid level in the evaporator, the liquid refrigerant liquid level detected by said means exceeds a predetermined value,
There is provided an absorption chiller-heater provided with a control means for controlling the liquid refrigerant to be sent to an absorber by opening the automatic valve.

[0009]

[Function] During operation, the refrigerant self-cleaning pipe sends the solution mixed in the evaporator together with the liquid refrigerant to the condenser, and when the operation is stopped, the automatic valve of the refrigerant blow pipe is opened to store the liquid accumulated in the condenser. By pouring the refrigerant into the absorber all at once, a small amount of solution carried to the condenser also flows into the absorber every time the refrigerator is stopped, so the refrigerant is automatically purified and operated for purification of the refrigerant. You don't have to stop.

Further, by making the refrigerant self-cleaning pipe U-shaped and providing the communication pipe, the differential pressure between the high-temperature high-pressure condenser and the low-temperature low-pressure evaporator is regulated in the U-shaped pipe when the refrigerant pump is stopped. It is possible to secure the stability of operation by absorbing by the accumulated liquid refrigerant and sealing between the condenser and the evaporator.

Further, a detecting means for detecting the liquid level of the liquid refrigerant is provided, and when the liquid level exceeds a predetermined value, the automatic valve is opened so that the liquid refrigerant in the condenser is flown into the absorber, thereby reducing the temperature of the absorber and the high temperature. Since it is possible to dilute the concentration of the solution in the regenerator, the low temperature regenerator, etc., crystallization of the solution system can be prevented.

[0012]

EXAMPLES The present invention will be described in detail below with reference to examples. FIG. 1 is a cooling cycle showing an embodiment of the absorption chiller-heater according to the present invention. In this figure, members designated by the same reference numerals as those in FIG. 2 are the same members. During normal operation of the cycle of FIG. 1, by operating the refrigerant pump 2 in the evaporator 1, the heat transfer tube 2 is transferred from the refrigerant distribution device 3 to the heat transfer tube 2.
The liquid refrigerant is sprayed on 0 and evaporates. At that time, the cold water flowing through the heat transfer tubes 20 is cooled and provided for cooling. The refrigerant vapor generated in the evaporator 1 is absorbed by the solution sprayed on the absorber 5. The absorbed heat generated at this time is radiated to the cooling water flowing in the heat transfer tube 21. The solution that has absorbed the refrigerant vapor in the absorber 5 is conveyed by the solution pump 7, is partially supplied to the high temperature regenerator 10 through the high temperature heat exchanger 9 and the low temperature heat exchanger 8, and the other is supplied. It is supplied to the low temperature regenerator 11. The solution in the high temperature regenerator 10 is heated by a heating source such as the combustor 12 to generate a refrigerant vapor and concentrate it. On the other hand, the solution in the low temperature regenerator 11 is heated by using the refrigerant vapor generated in the high temperature regenerator 10 as a heating source to generate and condense the refrigerant vapor.
Here, the refrigerant vapor used as a heating source is liquefied and flows into the condenser 13 as a liquid refrigerant. The refrigerant vapor generated in the low temperature regenerator 11 is cooled and condensed by the cooling water flowing in the heat transfer tube 21 in the condenser 13, and is returned to the evaporator 1 together with the liquid refrigerant from the low temperature regenerator 11. On the other hand, the solution in which the refrigerant vapor is generated and concentrated in the low-temperature regenerator 11 and the high-temperature regenerator 10 is returned to the absorber 5 via the high-temperature heat exchanger 9 and the low-temperature heat exchanger 8 and is dispersed.

In this cooling cycle, the refrigerant self-cleaning pipe 17, the refrigerant blow pipe 19, the liquid level sensor 25, and the controller 26, which characterize the present invention, function as follows. First,
During normal operation, a part of the liquid refrigerant branched from the refrigerant pump 2 is guided to the condenser 13 via the orifice or adjustment valve 16 and the self-cleaning pipe 17. At this time, a small amount of the solution accumulated in the evaporator 1 is also guided to the condenser 13. Here, the reason why the orifice or the adjusting valve 16 is used to throttle is to ensure that the liquid refrigerant necessary for the cooling operation is sufficiently distributed to the refrigerant distribution device 3. Next, the liquid refrigerant introduced to the condenser 13 and a small amount of the solution are stored in the condenser 13 in a constant amount during the cooling operation, and the liquid refrigerant in excess of the constant amount and the cooling water heat transfer pipe 2
The liquid refrigerant cooled and condensed in 1 is returned to the evaporator 1 together.

When the cooling operation is stopped, the control device 26 which detects this is output a signal S and opens the automatic valve 18. Then, the liquid refrigerant stored in the condenser 13 and the solution contained therein are sent to the absorber 5 from the refrigerant blow pipe 19. In this way, the liquid refrigerant is introduced into the solution circulating in the machine to reduce the concentration of the solution, and at the same time, the solution contained in the liquid refrigerant is also introduced into the solution system. That is, the liquid refrigerant purity of the evaporator 1 is improved.

As described above, the purification of the refrigerant is automatically performed every time the operation is stopped. However, if there is no special abnormality and the solution enters the liquid refrigerant in the normal operating condition, one day 1
Sufficient purification can be achieved by only stopping the operation once.

In the prior art, the structure in which the refrigerant blow pipe 19 of FIG. 1 is installed is provided for suppressing the residual refrigerating capacity and preventing the crystallization of the solution when the operation of the refrigerator is stopped.
In this embodiment, the pipe 19 is used and combined with the self-cleaning pipe 17 so as to have a self-cleaning function of the refrigerant.

Next, the control using the liquid level sensor 25 will be described. When the purity of the liquid refrigerant in the evaporator 1 is reduced, the evaporation action of the liquid refrigerant is reduced, the vapor does not move from the evaporator 1 to the absorber 5 as a refrigerant vapor, and the liquid refrigerant liquid level in the evaporator 1 rises. . Also, in the case of other abnormal operation, for example, when air leaks from the outside of the machine (usually high vacuum in the absorption chiller / heater) or when gas is generated from iron rust, these non-condensed gases cause evaporation. Even when it drops, the liquid level of the liquid refrigerant 4 rises. Even in these cases, when the operation is continued, the action of the liquid refrigerant (water) to dilute the solution is reduced, and the solution becomes over-concentrated, and when the solution concentration exceeds 65%, crystals are precipitated and the equipment may be damaged. There is.

Therefore, in this embodiment, the liquid level of the liquid refrigerant 4 is detected by the sensor 25, and when the liquid level exceeds the set value, the controller 26 outputs the signal S to output the automatic valve 1
8 is opened and the condenser 13 is operated in the same manner as when the operation is stopped.
If the liquid refrigerant of (3) is allowed to flow into the absorber 5, the concentration of the solution system can be reduced, which is a safe operation for preventing crystallization. In this case, the heating from the heating source such as the combustor 12 may be stopped by the control of the control device 26.

The refrigerant self-cleaning pipe 17 has a U-shaped portion, which is a differential pressure between the high pressure condenser 13 and the low pressure evaporator 1 when the refrigerant pump 2 is stopped. This prevents the refrigerant vapor from moving. That is, since the evaporator side 172 of the U-shaped portion is connected to the evaporator 1 through the communication pipe 24, the evaporator side 1 of the refrigerant self-cleaning pipe 17 that was filled with the liquid during the operation of the refrigerant pump 2.
The liquid level of 72 is the liquid refrigerant 4 of the evaporator 1 when the pump 2 is stopped.
Balance with the liquid surface of. On the other hand, the condenser side 171 of the refrigerant self-cleaning pipe 17 has a higher pressure than the condenser side 13 of the evaporator side 172.
Is pushed down by the pressure of 1, and absorbs the differential pressure with the evaporator 1 to form a liquid seal by the liquid refrigerant. By partitioning the condenser 13 filled with the high-temperature refrigerant vapor and the evaporator 1 having a low temperature for generating cold water in this manner, a rapid temperature change is prevented and a stable cooling operation is enabled. Here, the communication pipe 24 needs to be throttled by an orifice or a regulating valve 27 before connecting with the evaporator 1. This is because when the condenser 13 is arranged above the evaporator 1 as shown in FIG. 1, the liquid refrigerant does not reach the condenser 13 without a throttle.

[0020]

According to the present invention, the refining of the refrigerant is automatically performed when the operation is stopped. Therefore, the working efficiency is improved without lowering the refrigerating capacity during the operation. Further, there is an effect that the overconcentration of the solution due to the rise of the liquid refrigerant liquid level in the evaporator can be surely prevented. Further, in terms of structure, since it is only necessary to newly provide a refrigerant self-cleaning pipe, there is no complication.

[Brief description of drawings]

FIG. 1 is a cooling cycle in an embodiment of the absorption chiller-heater according to the present invention.

FIG. 2 is a conventional cooling cycle.

FIG. 3 is a conventional cooling cycle in which a liquid refrigerant is allowed to directly flow into a solution.

[Explanation of symbols]

 1 Evaporator 2 Refrigerant Pump 4 Liquid Refrigerant 5 Absorber 7 Solution Pump 8 Low Temperature Heat Exchanger 9 High Temperature Heat Exchanger 10 High Temperature Regenerator 11 Low Temperature Regenerator 12 Combustor 13 Condenser 16 Orifice or Adjustment Valve 17 Refrigerant Self Cleaning Pipe 18 Automatic Valve 19 Refrigerant blow pipe 24 Communication pipe 25 Liquid level sensor 26 Control device 27 Orifice or regulating valve

Claims (6)

[Claims] 1. An evaporator, an absorber, a condenser, a low temperature regenerator,
In an absorption chiller-heater having a high-temperature regenerator, a low-temperature heat exchanger, and a high-temperature heat exchanger, for branching the pipe from the refrigerant pump discharge pipe of the evaporator and guiding it to the condenser through an orifice or a regulating valve. An absorption chiller-heater comprising: a refrigerant self-cleaning pipe; and a refrigerant blow pipe for guiding a liquid refrigerant from a tank of a condenser storing the liquid refrigerant to an absorber through an automatic valve. 2. The refrigerant self-cleaning pipe has a rising portion rising upward from the branch point, a U-shaped portion having one end connected to an upper end of the rising portion, and the other end of the U-shaped portion condensed. And a connecting pipe for connecting the gas phase portion of the evaporator from the connection point of the rising portion and the U-shaped portion through an orifice or a regulating valve. Item 1. The absorption chiller-heater according to Item 1. 3. The absorption chiller-heater according to claim 1, further comprising a control means for controlling the liquid refrigerant to be sent to the absorber by opening the automatic valve when the operation is stopped. 4. A liquid level detecting means for detecting the height of the liquid refrigerant liquid level of the evaporator, and the automatic valve when the liquid refrigerant liquid level detected by the means exceeds a predetermined value. 4. An absorption chiller-heater according to any one of claims 1 to 3, further comprising a control means for controlling the liquid refrigerant to be opened and sent to the absorber. 5. An evaporator, an absorber, a condenser, a low temperature regenerator,
In a method for controlling an absorption chiller-heater having a high-temperature regenerator, a low-temperature heat exchanger, and a high-temperature heat exchanger, a part of the liquid refrigerant discharged from a refrigerant pump during operation is constantly sent to a condenser and A method for controlling an absorption chiller-hot water machine, which comprises sending the liquid refrigerant sent to the condenser to the absorber when stopped. 6. An evaporator, an absorber, a condenser, a low temperature regenerator,
In a method of controlling an absorption chiller-heater having a high-temperature regenerator, a low-temperature heat exchanger, and a high-temperature heat exchanger, a part of the liquid refrigerant discharged from a refrigerant pump during operation is constantly sent to a condenser and A method for controlling an absorption chiller-heater, characterized in that when the liquid refrigerant liquid level in the evaporator exceeds a predetermined value, the liquid refrigerant sent to the condenser is sent to the absorber.