JP3188111B2 - Absorption chiller / heater and control method thereof - 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 used in an air conditioner and the like, and more particularly to an absorption chiller / heater in which cold water and hot water are taken out of an evaporator through a common pipe. And its control method.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Publication No. 45-22072
In the technology described in the publication, as a main configuration, a condenser and an evaporator are connected via a U-shaped seal tube. A coolant is sealed in a U-shaped seal tube, and a cooling operation is performed by maintaining a pressure difference between the condenser and the evaporator, and a cooling water for circulating the cooling water to the refrigerant pump, the absorber, and the condenser in the cooling operation. The pump is stopped, the pressure in the condenser is increased, and the refrigerant sealed in the U-shaped seal tube and the refrigerant collected in the lower part of the evaporator are blown out to the evaporator side, and the U-shaped seal tube is used as a bubble pump. Thus, the heating operation is performed.

[0003]

In an absorption chiller / heater in which the above-mentioned conventional condenser and evaporator are connected via a U-shaped seal tube, for example, when the power is suddenly cut off during cooling operation, The refrigerant pump, the solution pump, and the regenerator heating source are stopped, and the cooling water pump for circulating the cooling water through the absorber and the condenser is stopped, so that the pressure of the condenser increases. As a result, the pressure difference between the condenser and the evaporator increases, and the refrigerant sealed in the U-shaped seal tube blows out to the evaporator side. Even when the operation is restarted after the power is restored, the refrigerant for liquid sealing in the U-shaped seal tube is pumped as a bubble pump until the pressure of the condenser and the evaporator is stabilized after the refrigerant blows out to the evaporator side. Since the refrigerant is liquefied, the refrigerant may not be sealed in the U-shaped seal tube, and the cooling operation may not be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to start the cooling operation smoothly even if the power is suddenly cut off during the cooling operation even if the operation is restarted. And a method of controlling the same.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide a cooling operation between both ends of a U-shaped seal pipe provided for absorbing a pressure difference between a condenser and an evaporator of an absorption type chiller / heater. A U-shaped seal is provided between both ends of a U-shaped seal pipe provided to absorb a pressure difference between a condenser and an evaporator of an absorption chiller / heater, which is achieved by bypassing during a power failure. This is achieved by bypassing when the temperature of the lower part of the condenser side of the pipe exceeds a predetermined value.After the power supply of the absorption type chiller / heater is stopped during the cooling operation, the power is restored to restart the cooling operation. At the same time, the refrigerant pump, the cooling water pump, and the chilled water pump are operated, and at the same time, a bypass pipe is provided between both ends of a U-shaped seal pipe provided for absorbing a pressure difference between the condenser and the evaporator. State and after a predetermined time has passed Close the serial bypass pipe is achieved by starting the operation.

[0006]

In an absorption type chiller / heater in which a condenser and an evaporator are connected via a U-shaped seal pipe, if the power is suddenly cut off during cooling operation and the pressure of the condenser rises, a U-shaped seal is used. By bypassing between both ends of the pipe with a bypass pipe, the pressure of the high-pressure condenser side and the low-pressure evaporator side are balanced before the refrigerant sealed in the U-shaped seal pipe blows out to the evaporator side. The refrigerant sealed in the U-shaped seal tube does not blow out to the evaporator side. Therefore, even if the operation is resumed after the power is restored, the cooling operation can be started up smoothly.

Further, when the pressure of the condenser excessively rises, for example, when non-condensable gas is generated, the temperature is detected at the lower part of the U-shaped seal tube on the condenser side, and the refrigerant is bypassed by a bypass pipe to thereby carry out the refrigerant. Blow-by can be prevented.

[0008] Further, at the time of a power failure, the above-mentioned blow-by occurs, and at the time of a subsequent power recovery, by operating each of the pumps for a certain period of time while first bypassing the above-mentioned bypass pipe, the temperature of the evaporator can be lowered to perform the cooling operation. The operation can be resumed smoothly in the state.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of an absorption type chiller / heater according to the present invention, in which a high-temperature regenerator 1, a low-temperature regenerator 2, a condenser 3,
Evaporator 4, absorber 5, solution pump 6, refrigerant pump 7, high-temperature heat exchanger 8, low-temperature heat exchanger 9, U-shaped seal tube 12 connecting condenser and evaporator, liquid refrigerant spray conduit 22, refrigerant dispersion Device 27, solution spraying device 26, ejector pump 14,
Gas-liquid separator 13, solution conduit 15, mixing chamber 16 for mixing the refrigerant and the solution, piping 19 for guiding the refrigerant collected in the lower part of gas-liquid separator 13 to mixing chamber 16, cooling water pump 1
0, a cooling tower 11, a pipe 20 for supplying the refrigerant of the evaporator 4 when using the U-shaped seal pipe 12 as a bubble pump, a movable valve 21, a bypass pipe 24 connecting the low-temperature regenerator 2 and the evaporator 4, and a uniform pipe. It comprises a pressure valve 25 and the like.

The normal operation of the absorption type water heater during the cooling operation will be described. During cooling operation, the movable valve 1
8, 21, and the pressure equalizing valve 25 are closed. Refrigerant vapor generated when the solution is heated by an external heat source and concentrated in the high-temperature regenerator 1 is guided into a heating tube of the low-temperature regenerator 2 to heat and concentrate the solution in the low-temperature regenerator 2, and to condense the refrigerant vapor. It is generated and condensed and liquefied and flows into the condenser 3. The refrigerant vapor generated in the low-temperature regenerator 2 is guided to the condenser 3, cooled by the cooling water to be condensed and liquefied, and sent to the evaporator 4 via the liquid refrigerant conduit (not shown) together with the refrigerant from the high-temperature regenerator 1. Can be

A part of the liquid refrigerant in the evaporator 4 is supplied to the U-shaped seal pipe 12 through the liquid refrigerant supply pipe 23 by the refrigerant pump 7, and the other part is sent to the refrigerant spraying device 27 through the liquid refrigerant spray conduit 22. Then, heat is exchanged with cold water flowing from the refrigerant spraying device 27 onto the evaporator heat transfer tube group and flowing through the tubes to evaporate and flow into the absorber 5. The cooling effect is exerted by the latent heat of evaporation at that time.

In the absorber 5, the concentrated solution concentrated in the high-temperature regenerator 1 and the low-temperature regenerator 2 is sprayed onto the group of absorber heat transfer tubes by the ejector pump 14 via the solution spraying device 26, and the cooling water flowing in the tubes. And absorbs the refrigerant vapor from the evaporator 4 to generate a dilute solution. A part of the dilute solution in the absorber 5 becomes a driving liquid for the ejector pump 14 by the solution pump 6 and is recirculated to the absorber 5. The remaining dilute solution is divided into two parts via a low-temperature heat exchanger 9, one of which is a low-temperature regenerator 2.
And the other is further supplied to the high-temperature regenerator 1 via the high-temperature heat exchanger 8. The cooling cycle is configured as described above.

The above is the outline of the operation of the cooling operation. When the operation is normally stopped, the external heat source, the refrigerant pump 7 and the cooling water pump 10 in the high temperature regenerator 1 are stopped.
Thereafter, a chilled water pump (not shown) for circulating chilled water in the evaporator heat transfer tube group and the solution pump 6 are configured to be stopped. Further, during operation, the movable valve 18 of the closed pipe 17 is opened, and the refrigerant stored in the condenser 3 is caused to flow to the absorber 5 through the mixing chamber 16 to perform a dilution operation of the solution. .

As described above, when the operation is stopped, the condenser 3
The cooling water pump 10 for cooling the
Pressure rises, and the refrigerant liquid sealed in the U-shaped seal tube 12 tries to blow out to the evaporator 4 side. However, as a dilution operation of the solution, the movable valve 18 of the pipe 17 which is closed during operation is opened to condense the solution. The refrigerant stored in the vessel 3 flows to the absorber 5 through the mixing chamber 16, and the solution is circulated by the solution pump 6. This prevents the refrigerant sealed in the U-shaped seal tube 12 from flowing to the evaporator 4 when the cooling operation is stopped.

However, if the power is turned off due to any cause during the cooling operation, for example, due to a power failure, the external heat source in the high temperature regenerator 1, the refrigerant pump 7, the solution pump 6, the cooling water pump 10, the cold water Since the pump (not shown) stops at the same time and the movable valve 18 of the pipe 17 remains closed, the dilution operation of the solution cannot be performed. FIG. 2 shows a time change of the pressures of the condenser 3 and the evaporator 4 at this time. If the power is turned off at a time A, the pressure of the condenser 3 starts to increase from this time, and Also increases. Due to this differential pressure, sealing by the U-shaped seal tube 12 cannot be performed. If the differential pressure at this time is D and the time is B, the refrigerant sealed in the U-shaped seal tube 12 at the time B evaporates. As a result, the pressure in the evaporator 4 rises sharply. In this case, even if the refrigerant sealed in the U-shaped seal tube 12 blows out to the evaporator 4 side and the U-shaped seal tube 12 is operating as a bubble pump, the power is restored and the operation is restarted. The temperature in the evaporator 4 has risen and the cooling operation does not start.

Therefore, in the present embodiment, the equalizing valve 25 of the bypass pipe 24 provided so as to connect the low-temperature regenerator 2 and the evaporator 4 is opened at the same time when the power is turned off.
Here, it is assumed that the pressure equalizing valve 25 is an electromagnetic valve that is closed when the power is turned on, but is opened when the power is turned off. At this time, as shown in FIG. 3, when the power is turned off at time A, the pressure equalizing valve 25 is opened from time A, so that the refrigerant vapor generated in the high temperature regenerator 1 Flows into the evaporator 4, thereby preventing an excessive rise in the pressure of the condenser 3 and changing the pressure of the evaporator 4 together with the condenser 3, so that the condenser 3 and the evaporator 4 And the pressure difference between the refrigerant evaporator 4 and the liquid-sealed refrigerant in the U-shaped seal tube 12 can be maintained.
A blow-by to the side can be prevented. As described above, the cooling operation can be smoothly started when the operation is restarted after the power is restored, regardless of the elapsed time since the power was turned off.

FIG. 4 shows another embodiment of the absorption type chiller / heater according to the present invention, in which a U-shaped sealing pipe is provided between the liquid level on the condenser 3 side of the U-shaped sealing pipe 12 and the bottom. A control device 2 for attaching a temperature detecting device 28 for detecting the temperature in the inside 12 and taking in the output to control the pressure equalizing valve 25 and a bleed valve 30 provided in a pipe connecting the bleed device 31 and the condenser 3.
9 are installed.

Although the purpose of the embodiment shown in FIG. 1 is to prevent the U-shaped seal tube 12 from blowing through during a power failure,
In addition to the power failure, there are (1) when the non-condensable gas accumulates in the condenser 3 and (2) when the liquid level in the low-temperature regenerator 2 drops due to poor circulation of the solution around the low-temperature regenerator 2. ,
(3) When excessive gas is input to the high temperature regenerator 1,
(4) This may occur when the circulation of cooling water becomes poor. In these cases, the pressure and temperature in the condenser 3 increase, and the refrigerant liquid in the U-shaped seal tube 12 is pushed from the condenser 3 side and the liquid level decreases. Accordingly, the temperature of the temperature detector 28 increases. Therefore, during the cooling operation, the control device 28 checks the temperature detected by the temperature detection device 28 at regular intervals, and when it is determined that the temperature has become higher than the preset temperature, the control device 29 opens the equalizing valve 25 by the control device 29. The refrigerant sealed in the U-shaped seal tube 12 is prevented from flowing to the evaporator 4 side.

If the cause of the pressure rise is caused by the non-condensable gas by the control device 29 alone or in conjunction with the pressure equalizing valve 25, the bleed valve 30 is opened to start the bleed device 31, and the high temperature regeneration is performed. In the case of excessive gas input to the reactor 1 or poor cooling water circulation, the amount of gas input to the high temperature regenerator 1 is forcibly suppressed. In this way, U
It is possible to directly prevent the pressure in the condenser 3 from rising such that the refrigerant in the U-shaped seal tube 12 blows toward the evaporator 4.

As described above, the temperature in the U-shaped seal tube 12 is grasped by the control device 29 during the cooling operation, whereby
It is possible to prevent an excessive rise in pressure on the condenser 3 side such that the refrigerant sealed in the U-shaped seal tube 12 blows out to the evaporator 4 side.

The pressure equalizing valve 25 is controlled by a control device 29 in accordance with the output of the temperature detecting device 28.
If the equalizing valve 25 is an electromagnetic valve similar to that of the embodiment of FIG. 1, it is automatically opened even at the time of a power failure, and has the same effect as that of the embodiment of FIG.

FIG. 5 shows a modification of the embodiment of FIG. 1. In FIG. 1, the low-temperature regenerator 2 and the evaporator 4 are used to bypass the bypass pipe 24 via the equalizing valve 25 and the U-shaped seal pipe 12.
Which is attached to the upper part of the U-shaped seal tube 12 itself. Then, when the power is cut off for some reason during the cooling operation, the equalizing valve 25 of the bypass pipe 24 connected to the U-shaped seal pipe 12 is opened, whereby
Can obtain the same effect as the first embodiment shown in FIG.
Since the refrigerant in the U-shaped seal tube 12 can be stopped without blowing to the evaporator 4 side, the cooling operation can be smoothly started when the operation is resumed after the power is restored, regardless of the elapsed time after the stop.

In the above embodiment, the pressure equalizing valve 2
Numeral 5 is a solenoid valve that opens automatically when the power is turned off and closes when the power is turned on. However, the present invention can also be configured using a pressure equalizing valve that requires a power supply for opening and closing. One of the methods is a configuration shown in FIG. 4 in which a power supply of a different system from the absorption chiller / heater, for example, a backup power supply at the time of power failure is prepared in the control device 29, and when the power failure occurs, the pressure equalizing valve is opened by the backup power supply. Things.

If no separate power supply is provided,
With the configuration described above, the control device 29 performs control as shown in FIG. That is, when the power is restored after the power failure (step 60).
1) It is checked whether the temperature detected by the temperature detecting device 28 is equal to or higher than a set value (step 602). The set value here is a value for detecting a temperature that is measured when a power failure causes a blow-through of the U-shaped seal tube and the inside of the U-shaped seal tube is at a high temperature. If the detected temperature is equal to or lower than the set value, the normal cooling operation is immediately started (step 608).
However, when the temperature exceeds the set value, the pressure equalizing valve 25 is opened (step 603, in which case the power supply for valve driving is alive because the power has just been restored), and the refrigerant pump 7, the cooling water pump 1
0, and operate a chilled water pump (not shown) and wait for a predetermined time (steps 604 to 606). Thereby, the evaporator 4
Since the inside temperature is lowered and the cooling operation can be performed, the pressure equalizing valve 25 is closed (step 607), and the cooling operation is started (step 608).

According to the present embodiment, even if the U-shaped seal tube blows through during a power failure, the evaporator can be started after the cooling operation can be performed.

[0026]

As described above, according to the present invention,
When the power is suddenly cut off during the cooling operation, the bypass is connected by a bypass pipe 24 via a pressure equalizing valve 25 so as to bypass the liquid level of the refrigerant liquid sealed in the U-shaped seal pipe 12 during the cooling operation. By opening the pressure equalizing valve 25 of the pipe 24, the refrigerant sealed in the U-shaped seal tube 12 does not blow out to the evaporator 4 side, and the operation can be resumed after the power is returned, so that the cooling operation can be started up smoothly. .

Further, even if the U-shaped seal tube is turned off during a power failure, the state of the evaporator can be automatically restored when the power is restored, so that the cooling operation can be started smoothly.

Further, even when the pressure of the condenser 3 rises for some reason during the cooling operation and the refrigerant sealed in the U-shaped seal tube 12 blows out to the evaporator 4 side, the pressure equalizing valve 25 is also used.
, It is possible to prevent an excessive rise in the pressure of the condenser 3 such that the refrigerant sealed in the U-shaped seal tube 12 blows out to the evaporator 4 side.

[Brief description of the drawings]

FIG. 1 is a cycle configuration diagram showing one embodiment of an absorption-type hot / cold water heater according to the present invention.

FIG. 2 is a diagram showing an example of pressure changes in a condenser and an evaporator when power is turned off in a conventional cooling cycle.

FIG. 3 is a diagram illustrating an example of pressure changes in a condenser and an evaporator when power is turned off in the cooling cycle of FIG. 1;

FIG. 4 is a cycle configuration diagram showing a second embodiment of the absorption chiller / heater according to the present invention.

FIG. 5 is a modification of the embodiment of FIG.

FIG. 6 is a flowchart illustrating a control method at the time of a power failure when a pressure equalizing valve that requires a power supply for opening and closing is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High-temperature regenerator 2 Low-temperature regenerator 3 Condenser 4 Evaporator 5 Absorber 12 U-shaped seal tube 24 Bypass piping 25 Equalization valve 28 Temperature detector 29 Control device 30 Bleed valve 31 Bleed device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-229645 (JP, A) JP-A-60-71864 (JP, A) JP-A-3-37368 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) F25B 15/00 306 F25B 15/00 303

Claims (5)

(57) [Claims] 1. An absorption chiller / heater having a condenser and an evaporator, a U-shaped seal provided between the condenser and the evaporator to absorb a pressure difference between the condenser and the evaporator. Tubes and
A bypass pipe through a pressure equalizing valve for equalizing the pressure between both ends of the U-shaped seal pipe, and means for controlling the pressure equalizing valve so that the pressure equalizing valve is opened when a power supply of the absorption chiller / heater is out of power. And an absorption chiller / heater. 2. The pressure equalizing valve operates a refrigerant pump, a cooling water pump, and a chilled water pump when power is restored and cooling operation is resumed after the power supply of the absorption type chiller / heater has been stopped during cooling operation. 2. The absorption type chiller / heater according to claim 1, wherein the chiller is set to an open state at the same time as the operation, and is controlled to be set to a closed state after a lapse of a predetermined time. 3. An evaporator, an absorber, a condenser, a low-temperature regenerator,
In a control method of an absorption chiller / heater having a high-temperature regenerator, a low-temperature heat exchanger, and a high-temperature heat exchanger, a U-shape provided for absorbing a pressure difference between the condenser and the evaporator. A method for controlling an absorption type water cooler / heater, characterized in that a portion between both ends of a seal pipe is bypassed during a power failure during a cooling operation. 4. An evaporator, an absorber, a condenser, a low-temperature regenerator,
In a control method of an absorption chiller / heater having a high-temperature regenerator, a low-temperature heat exchanger, and a high-temperature heat exchanger, a U-shape provided for absorbing a pressure difference between the condenser and the evaporator. A method for controlling an absorption-type water cooler / heater, comprising: bypassing a portion between both ends of a seal tube when a temperature of a lower portion of a U-shaped seal tube on a condenser side exceeds a predetermined value. 5. An evaporator, an absorber, a condenser, a low-temperature regenerator,
In the control method of the absorption chiller / heater having the high temperature regenerator, the low temperature heat exchanger, and the high temperature heat exchanger, after the power supply of the absorption chiller / heater is interrupted during the cooling operation, the power is restored and the cooling is performed. When the operation is resumed, the refrigerant pump, the cooling water pump, and the chilled water pump are operated, and at the same time, between both ends of the U-shaped seal pipe provided for absorbing the pressure difference between the condenser and the evaporator. A method for controlling an absorption-type water chiller / heater, wherein a bypass state is established by a bypass pipe, and after a predetermined time has elapsed, the bypass pipe is closed and operation is started.