JPH09189458A - Method for controlling absorbed chiller heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a vacuum condition within an absorbed chiller heater and maintain a reliability in operation of the machine even in the case of performing a heating operation at the machine. SOLUTION: This chiller heater is comprises a high temperature regenerator 1 for heating absorbing liquid; a separator 2 connected to the high temperature regenerator 1 so as to separate gas and liquid; an evaporator 5 for evaporating liquid refrigerant on a heat transfer pipe 16 of the evaporator installed in it and for cooling thermal medium within the heat transfer pipe 16 of the evaporator; a pipe for communicating the separator 2 with the evaporator 5 through a cooling or heating changing-over valve 10. Then, a pressure of the evaporator is set in advance in the case that non- condensed gas corresponding to a temperature of the thermal medium at an outlet of the heat transfer pipe of the evaporator is not present during a heating operation in which the cooling or heating changing-over valve 10 is opened, the temperature of the thermal medium at the outlet of the heat transfer pipe of the evaporator is detected, the pressure of the evaporator set in response to the detected temperature of the thermal medium is calculated and it is discriminated whether or not an amount of non-condensed gas within a circulating system is within an allowable range in response to a difference between the set pressure of the evaporator and the detected pressure of the evaporator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an absorption chiller-heater, and more particularly to a method for controlling an in-machine vacuum state during heating operation.

[0002]

2. Description of the Related Art When non-condensable gas is present in the refrigerant circulation system of an absorption chiller-heater, all the non-condensable gas gathers in the absorber during cooling operation and is collected in a gas storage chamber by an extraction device. It is discharged outside the aircraft. On the other hand, during the heating operation, as shown in FIG. 11, because the boiler operation is performed, the extraction device does not work and the non-condensable gas cannot be extracted. The non-condensable gas during heating operation has not been a problem so far because it can be operated without any problem.

[0003]

However, when the amount of non-condensable gas in the system increases due to leaks from the outside of the machine, the internal pressure of the machine rises, and the high temperature regenerator temperature is stopped. Also, if the non-condensable gas was air due to an external leak,
The system is operated in the presence of oxygen in the system, which promotes internal corrosion. In the prior art, even if there is non-condensable gas in the system, the high temperature regenerator will continue to operate until abnormal temperature is activated, resulting in the progress of internal corrosion during that time, resulting in a decrease in device reliability. Was there.

An object of the present invention is to maintain the internal vacuum state and maintain the reliability of the apparatus even during the heating operation of the absorption chiller-heater.

[0005]

In the heating operation, the refrigerant vapor generated in the high temperature regenerator gives heat to the hot water (heat medium) flowing in the heat transfer tube on the evaporator heat transfer tube, and is condensed to water. Therefore, the pressure of the evaporator is the pressure at which the refrigerant vapor is condensed, that is, the saturated vapor pressure. When there is no non-condensable gas in the system, this saturated vapor pressure is determined by the hot water outlet temperature at the outlet of the evaporator heat transfer tube, so the evaporator pressure fluctuates as shown in FIG. 3 depending on the hot water outlet temperature. On the other hand, when the non-condensable gas is present in the system, the non-condensable gas is dispersedly present in the low pressure part of the evaporator, the absorber and the condenser during the heating operation. The evaporator pressure in this state is the saturated vapor pressure plus the partial pressure of the gas, and the presence of the non-condensable gas results in an increase in the evaporator pressure. As shown in FIG. 2, the evaporator pressure increases in proportion to the amount of noncondensable gas.

In order to achieve the above object, the present invention provides a high temperature regenerator for heating an absorbing liquid, a separator connected to the high temperature regenerator for gas / liquid separation, and a liquid on an evaporator heat transfer tube installed therein. An evaporator that evaporates the refrigerant to cool the heat medium in the evaporator heat transfer tube, and a pipe that connects the separator and the evaporator via a cooling / heating switching valve, and an absorption type chiller / heater In the control method, during heating operation in which the cooling / heating switching valve is opened, the evaporator pressure in the case where there is no noncondensable gas corresponding to the heat medium temperature at the evaporator heat transfer tube outlet is set in advance, and the evaporator transfer is performed. The heat medium temperature Ta at the heat pipe outlet is detected, the set evaporator pressure Peva is calculated according to the detected heat medium temperature Ta, and the evaporator pressure Pa is detected,
It is characterized in that whether or not the amount of the non-condensable gas in the circulation system is within the allowable range is determined based on the difference between the evaporator pressure Peva and the evaporator pressure Pa.

To determine if the amount of non-condensable gas in the circulation system is within an acceptable range, the evaporator pressure Peva
And the evaporator pressure Pa (Pa-Peva) is greater than a preset value ΔP, and Pa-Peva> Δ
When P, an alarm may be displayed.

The above-mentioned problem is also solved by evaporating a liquid refrigerant on a high-temperature regenerator for heating the absorbing liquid, a separator connected to the high-temperature regenerator for gas-liquid separation, and evaporating a liquid refrigerant on an evaporator heat transfer tube installed therein. In the method for controlling an absorption chiller-heater configured to include an evaporator that cools a heat medium in a heat exchanger tube, and a pipe that connects the separator and the evaporator via a heating / cooling switching valve, During the heating operation in which the switching valve is opened, the high temperature regenerator temperature Tb when there is no noncondensable gas corresponding to the heat medium temperature at the evaporator heat transfer tube outlet is set in advance, and the heat at the evaporator heat transfer tube outlet is set. The medium temperature Ta is detected, the set high temperature regenerator temperature Tb is calculated according to the detected heat medium temperature Ta, the high temperature regenerator temperature Tc is detected, and the high temperature regenerator temperature Tc and the high temperature regenerator temperature Tb are detected. Of the noncondensable gas in the circulation system based on the difference between There is also achieved by a control method for the determination as to whether it is within the allowable range absorption chiller.

Whether or not the amount of non-condensable gas in the circulation system is within the allowable range is determined by comparing the difference (Tc-Tb) between the high temperature regenerator temperature Tc and the high temperature regenerator temperature Tb with a preset value ΔT. It is judged by whether it is large, (Tc-Tb)> ΔT
At this time, an alarm may be displayed.

[0010]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention will be described below with reference to FIG. The absorption chiller-heater shown in FIG.
A high temperature regenerator 1 for heating the dilute solution, a separator 2 arranged above the high temperature regenerator 1 and connected to the high temperature regenerator 1 by a rising pipe 26 for separating the dilute solution into a refrigerant vapor and an intermediate concentrated solution, and an interior The low temperature regenerator 3 in which one end of the refrigerant vapor coil is connected to the gas phase part of the separator 2 and the cooling water coil is incorporated.
A condenser 4 to which the other end of a refrigerant vapor coil installed inside is connected, and an evaporator 5 connected to the condenser 4 by a liquid refrigerant pipe 15.
An evaporator heat transfer tube 16 installed in the evaporator 5, an absorber 6 communicating with the evaporator 5 through a refrigerant vapor passage, and a suction solution side connected to the bottom of the absorber 6 via a dilute solution pipe 22. The solution circulation pump 9, a low temperature solution heat exchanger 8 in which the heated fluid inlet side is connected to the discharge side of the solution circulation pump 9 via a dilute solution pipe 23, and the heated fluid outlet side of the low temperature solution heat exchanger 8. A high temperature solution heat exchanger 7 connected to the heated fluid inlet side via a dilute solution pipe 24; and a dilute solution pipe 25 connecting the heated fluid outlet side of the high temperature solution heat exchanger 7 to the high temperature regenerator 1. A heating pipe 17 connecting the separator 2 and the evaporator 5 via a heating / cooling switching valve 10, and an intermediate concentrated solution pipe connecting the liquid phase portion of the separator 2 and the heating fluid inlet side of the high temperature solution heat exchanger 7. 18, an intermediate concentrated solution pipe 19 that connects the low temperature regenerator 3 and the heating fluid outlet side of the high temperature solution heat exchanger 7, A concentrated solution pipe 20 connecting the heating fluid inlet side of the temperature regenerator 3 and the low temperature solution heat exchanger 8 and a concentrated solution pipe 21 connecting the heating fluid outlet side of the low temperature solution heat exchanger 8 and the upper part of the absorber 6. , A hot water outlet temperature sensor 11 for measuring and outputting the hot water outlet temperature Ta of the evaporator heat transfer tube 16, an evaporator pressure sensor 12 for detecting and outputting the pressure Pa of the evaporator 5, a hot water outlet temperature sensor 11 and an evaporator pressure The controller 13 includes a controller 13 that determines whether the evaporator pressure is within an appropriate range based on the output of the sensor 12, and an alarm issuing unit 14 that issues an alarm according to the output of the controller 13.

The absorption chiller-heater having the above structure is operated as follows during heating operation. The cooling / heating switching valve 10 is opened. The dilute solution heated in the high temperature regenerator 1 rises to the separator 2 via the rising pipe 26, and in the gas-liquid mixed state in which the refrigerant vapor and the intermediate concentrated solution are mixed from the separator 2, the heating / cooling switching valve 10 and the heating pipe. It flows into the evaporator 5 via 17. The refrigerant vapor flowing into the evaporator 5 gives heat to the hot water that is the heat medium flowing through the evaporator heat transfer tube 16, and condenses itself to become a liquid refrigerant (water).
The liquid refrigerant is mixed with the intermediate concentrated solution flowing into the evaporator 5 to form a dilute solution, which is pressurized by the solution circulation pump 9 and passed through the low temperature solution heat exchanger 8 and the high temperature solution heat exchanger 7 to obtain the high temperature regenerator 1.
And the above cycle is repeated. The hot water flowing in the evaporator heat transfer tube 16 is heated by the heat of the refrigerant vapor to reach a high temperature, is guided to the heating load and radiates heat.

The controller 13 has a hot water outlet temperature Ta.
Is stored, and the output of the evaporator pressure sensor 12 (evaporator pressure Pa) is the output of the hot water outlet temperature sensor 11 as shown in FIG. It is determined whether or not the pressure is within the range of allowable pressure with respect to (hot water outlet temperature Ta). When the output Pa of the evaporator pressure sensor 12 is higher than the allowable evaporator pressure, the controller 13 outputs a signal instructing the alarm transmission means 14 to transmit an alarm. The alarm transmitting means 14 that has received the signal for instructing the alarm transmission uses a predetermined method (voice,
Alternatively, the driver is notified by issuing an alarm by blinking the display or the like, or printing output. The in-machine vacuum state shown by the solid line in FIG. 4 indicates the evaporator pressure Peva that should be maintained in the normal operating state (state in which no non-condensable gas does not exist) that is preset for the hot water outlet temperature, and is actually higher than this pressure. If the pressure is high, then non-condensable gas is present. In the figure, when the difference (Pa−Peva) between the output Pa of the evaporator pressure sensor 12 and the pressure Peva in the normal operation state is larger than ΔP,
An alarm is sent. The value of ΔP needs to be set according to the characteristics of each absorption chiller-heater. FIG. 5 shows a flowchart of the control procedure.

According to the present embodiment, even during heating operation, it can be immediately known that the non-condensable gas in the refrigerant circulation system exceeds the allowable range, and necessary measures such as evacuation can be taken. Since this can be done, the progress of corrosion on the inner surface of the device can be prevented.

A second embodiment of the present invention will be described with reference to FIG. The absorption chiller-heater shown in FIG. 6 differs from the absorption chiller-heater shown in FIG. 1 in that a high-temperature regenerator temperature sensor 27 for detecting the internal temperature Tc of the high-temperature regenerator 1 is provided, and the controller 13 has an evaporator. Instead of the output of the pressure sensor 12, the output of the high temperature regenerator temperature sensor 27 is input, and the controller 13 is based on the output of the high temperature regenerator temperature sensor 27 and the output of the hot water outlet temperature sensor 11. It is configured to determine the amount of non-condensable gas. The other structure is the same as that of the absorption chiller-heater shown in FIG.

In the heating operation, when there is no non-condensable gas in the machine and it is in vacuum, the pressure balance between the high temperature regenerator 1 and the evaporator 5 is expressed by the following equation. Phge = Peva + ΔP (1) Here, Phge: Saturated vapor pressure of the high temperature regenerator Peva: Saturated vapor pressure of the evaporator ΔPL: Pressure loss in the flow path from the high temperature regenerator to the evaporator Peva in the equation (1), Since ΔPL is determined by the hot water outlet temperature Ta, Phge is a function of the hot water outlet temperature Ta. The high temperature regenerator temperature Tc is determined by Phge and the solution concentration. In heating operation, the solution concentration in the high temperature regenerator hardly changes, so the high temperature regenerator temperature Tc is Ph.
It is determined by ge, that is, it is a function of the hot water outlet temperature Ta.

On the other hand, when non-condensable gas is present in the machine,
This non-condensable gas is dispersedly present in the low pressure part of the evaporator, the absorber and the condenser in the heating operation. The pressure of the evaporator in this state is a value obtained by adding the partial pressure Pg of the non-condensable gas in the evaporator to the above Peva, and as a result, Ph
ge is calculated by the following equation (2). Phge = Peva + Pg + ΔP (2) As is clear from the equations (1) and (2), the presence of the non-condensable gas causes an increase in Phge, and an increase in pressure results in an increase in temperature. The presence of the condensable gas can be grasped by the rise of the high temperature regenerator temperature Tc. The above is illustrated in FIGS. 7 and 8. FIG. 7 shows the relationship between the in-machine non-condensable gas amount and the high temperature regenerator temperature Tc when the hot water outlet temperature Ta is constant, and FIG. 8 shows the relationship between the hot water outlet temperature Ta and the high temperature regenerator temperature Tc when the in-machine gas amount is zero and This is a comparison with the gas amount A. Actually, the hot water outlet temperature Ta and the high temperature regenerator temperature Tc are detected, and the controller 13 determines whether or not the detected high temperature regenerator temperature Tc is within the alarm operation area shown in FIG. The high temperature regenerator temperature Tb when the in-machine gas amount is zero is set in advance corresponding to the hot water outlet temperature, and the high temperature regenerator temperature Tb when the in-machine gas amount is zero is calculated based on the detected hot water outlet temperature Ta. To do. The difference between the calculated high temperature regenerator temperature Tb and the detected high temperature regenerator temperature Tc (Tc-Tb = T
d) is obtained, and then Td is compared with ΔT to determine whether or not the high temperature regenerator temperature Tc is within the alarm operating range shown in FIG. When it is determined that the detected high temperature regenerator temperature Tc is within the alarm operating area shown in FIG. 9, the controller 13 outputs a signal for instructing the alarm display means 14 to display an alarm, and the alarm transmission means 14 is evacuated. The alarm indicating the necessity of is displayed by voice, blinking light, or printed output.

In the figure, an alarm is issued when the output Tc of the high temperature regenerator temperature sensor 27 is higher than the temperature in the normal operating state (state where the amount of non-condensable gas is zero) by ΔT or more. The value of ΔT needs to be set according to the characteristics of each absorption chiller-heater. FIG. 10 shows a flowchart of the above control procedure.
Instead of managing with ΔT, as shown in FIG. 8, the degree of the noncondensable gas amount is judged using the high temperature regenerator temperature and the hot water outlet temperature, and the noncondensable gas amount exceeds the predetermined gas amount A. You may make it send out an alarm when it starts.

Also in this embodiment, as in the case of the first embodiment, it should be immediately known that the non-condensable gas in the refrigerant circulation system exceeds the allowable range even during the heating operation. Since it is possible to perform necessary measures such as vacuuming,
It is possible to prevent the corrosion of the inner surface of the device.

[0019]

According to the present invention, since the in-machine vacuum state during heating operation can be monitored, it is possible to minimize the internal corrosion due to the outside of the machine, and the reliability of the equipment is improved.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an example of an absorption chiller-heater to which the present invention is applied.

FIG. 2 is a conceptual diagram showing the relationship between evaporator pressure and the amount of non-condensable gas in the machine.

FIG. 3 is a conceptual diagram showing the relationship between evaporator pressure and hot water outlet temperature.

FIG. 4 is a conceptual diagram showing a relationship among an evaporator pressure, a hot water outlet temperature, and an alarm area.

FIG. 5 is a flowchart showing a first embodiment of the present invention.

FIG. 6 is a system diagram showing another example of an absorption chiller-heater to which the present invention is applied.

FIG. 7 is a conceptual diagram showing the relationship between the temperature of the high temperature regenerator and the amount of non-condensable gas in the machine.

FIG. 8 is a conceptual diagram showing the relationship between the high temperature regenerator temperature and the hot water outlet temperature.

FIG. 9 is a conceptual diagram showing a relationship among a high temperature regenerator temperature, a hot water outlet temperature and an alarm area.

FIG. 10 is a flowchart showing a second embodiment of the present invention.

FIG. 11 is a system diagram showing an example of an absorption chiller-heater.

[Explanation of symbols]

1 High Temperature Regenerator 2 Separator 3 Low Temperature Regenerator 4 Condenser 5 Evaporator 6 Absorber 7 High Temperature Solution Heat Exchanger 8 Low Temperature Solution Heat Exchanger 9 Solution Circulation Pump 10 Cooling / heating Switching Valve 11 Hot Water Outlet Temperature Sensor 12 Evaporator Pressure Sensor 13 Controller 14 Alarm Transmitting Means 15 Liquid Refrigerant Pipe 16 Evaporator Heat Transfer Pipe 17 Heating Pipe 18, 19
Intermediate concentrated solution pipe 20,21 Concentrated solution pipe 22,23,
24,25 Dilute solution pipe 26 Rise pipe 27 High temperature regenerator temperature sensor

Claims (4)

[Claims] 1. A high temperature regenerator for heating an absorbing liquid, a separator connected to the high temperature regenerator for gas-liquid separation, and an evaporator heat transfer tube for evaporating a liquid refrigerant on an evaporator heat transfer tube installed therein. In the method for controlling an absorption chiller-heater configured to include an evaporator that cools the heat medium, and a pipe that connects the separator and the evaporator via a cooling / heating switching valve, the cooling / heating switching valve is opened. During the heating operation performed, the evaporator pressure is set in advance when there is no non-condensable gas corresponding to the heat medium temperature at the evaporator heat transfer tube outlet, and the heat medium temperature Ta at the evaporator heat transfer tube outlet is detected. The calculated evaporator pressure Peva is calculated according to the detected heat medium temperature Ta, the evaporator pressure Pa is detected, and the failure in the circulation system is detected based on the difference between the evaporator pressure Peva and the evaporator pressure Pa. Determine if the amount of condensable gas is within acceptable limits The method of an absorption chiller-heater is characterized and. 2. A high-temperature regenerator for heating the absorbing liquid, a separator connected to the high-temperature regenerator for gas-liquid separation, and an evaporator heat transfer tube in which the liquid refrigerant is evaporated to evaporate the liquid refrigerant. In the method for controlling an absorption chiller-heater configured to include an evaporator that cools the heat medium, and a pipe that connects the separator and the evaporator via a cooling / heating switching valve, the cooling / heating switching valve is opened. During the heating operation performed, the evaporator pressure is set in advance when there is no non-condensable gas corresponding to the heat medium temperature at the evaporator heat transfer tube outlet, and the heat medium temperature Ta at the evaporator heat transfer tube outlet is detected. The calculated evaporator pressure Peva is calculated according to the detected heat medium temperature Ta, the evaporator pressure Pa is detected, and the difference (Pa-Peva) between the evaporator pressure Peva and the evaporator pressure Pa is preset. It is determined whether it is larger than the determined value ΔP, and Pa-Peva> A method for controlling an absorption chiller-heater characterized by displaying an alarm when ΔP. 3. A high temperature regenerator for heating the absorbing liquid, a separator connected to the high temperature regenerator for separating gas and liquid, and an evaporator heat transfer tube for evaporating a liquid refrigerant on an evaporator heat transfer tube installed therein. In the method for controlling an absorption chiller-heater configured to include an evaporator that cools the heat medium, and a pipe that connects the separator and the evaporator via a cooling / heating switching valve, the cooling / heating switching valve is opened. During the heating operation performed, the high temperature regenerator temperature Tb in the case where there is no noncondensable gas corresponding to the heat medium temperature at the evaporator heat transfer tube outlet is set in advance, and the heat medium temperature Ta at the evaporator heat transfer tube outlet is set. Detected and detected heat medium temperature Ta
Calculating the set high temperature regenerator temperature Tb according to
The high temperature regenerator temperature Tc is detected, and it is determined whether or not the amount of non-condensable gas in the circulation system is within an allowable range based on the difference between the high temperature regenerator temperature Tc and the high temperature regenerator temperature Tb. Control method for absorption type water heater and chiller. 4. A high-temperature regenerator for heating the absorbing liquid, a separator connected to the high-temperature regenerator for separating gas and liquid, and an evaporator heat transfer tube for evaporating a liquid refrigerant on an evaporator heat transfer tube installed therein. In the method for controlling an absorption chiller-heater configured to include an evaporator that cools the heat medium, and a pipe that connects the separator and the evaporator via a cooling / heating switching valve, the cooling / heating switching valve is opened. During the heating operation performed, the high temperature regenerator temperature Tb in the case where there is no noncondensable gas corresponding to the heat medium temperature at the evaporator heat transfer tube outlet is set in advance, and the heat medium temperature Ta at the evaporator heat transfer tube outlet is set. Detected and detected heat medium temperature Ta
Calculating the set high temperature regenerator temperature Tb according to
The high temperature regenerator temperature Tc is detected, and the difference (Tc-Tb) between the high temperature regenerator temperature Tc and the high temperature regenerator temperature Tb is a preset value Δ.
It is determined whether or not it is larger than T, and (Tc-Tb)> ΔT
A method for controlling an absorption chiller-heater characterized by displaying an alarm at the time.