JP3819485B2 - Operation control method of absorption chiller / heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to control of an absorption chiller / heater that can supply cold water and hot water simultaneously so that cooling and heating can be performed simultaneously.
[0002]
[Prior art]
In the cold / hot water simultaneous supply type absorption chiller / heater, in general, the cold water supply is controlled mainly by the cold water supply, and the hot water supply is controlled by the slave, and conversely, the warm water supply is controlled by the main and the cold water supply is controlled by the slave. For example, as shown in FIG. 4, the temperature of the chilled water that has been recirculated to cool mainly with the heat of evaporation of the refrigerant, that is, the temperature of the refrigerated cold water t, and the refrigerant has recirculated mainly to be heated with the heat of condensation. Based on the temperature of the hot water, that is, the refluxing hot water temperature T, the region was clearly divided.
[0003]
[Problems to be solved by the invention]
However, in the conventional cold / hot water simultaneous supply type absorption chiller / heater, the cooling load (for example, cooling load) and the heating load (for example, heating load) are both low, that is, 7.0, for example. Cooling water that is circulated and supplied with chilled water with a target of ℃ circulates chilled water that is slightly higher than 7.0 ℃, for example, 7.3 ℃ or less, and circulates hot water that is heated to 5,000 ℃, for example. In a load state in which warm water having a temperature slightly lower than 55.0, for example, 54.7 ° C. or higher, is recirculated from the supplied heating load, combustion of a combustor such as a gas burner provided in the high-temperature regenerator is turned on / off. Since the heat input is controlled after being turned off, it becomes difficult to control the cold water and the hot water to a predetermined target temperature. In particular, the switching between the cold main operation and the warm main operation is performed based only on the temperature of the cold water and the warm water returning to the absorption chiller / heater after finishing the cooling / heating action. The main operation is frequently switched, and there is a problem that stable control of the cold water temperature and the hot water temperature becomes more difficult, and the solution to this point has been a problem.
[0004]
[Means for Solving the Problems]
In the present invention, as a specific means for solving the above-mentioned problems of the prior art, a regenerator, a condenser, an evaporator, an absorber, and the like are connected to form a circulation cycle of a refrigerant and an absorbing liquid. Refrigerant liquid that has passed through the inside and circulated cooling water that has been cooled to the first predetermined temperature t1 as a target and circulated to the cooling load and refrigerant vapor flows from the regenerator and is condensed by heat exchange is regenerated. A hot water supply path for supplying hot water to the heating load by circulating water through a container that circulates into the vessel to target the first predetermined temperature T1 for cooling during the cold water / hot water simultaneous supply operation Based on the temperature of the water that passes through the evaporator (hereinafter referred to as reflux cold water temperature) t or the temperature of the water that passes through the vessel for heating (hereinafter referred to as reflux hot water temperature) T, the cold water main, hot water subordinate ( Hereinafter, cold main operation), or hot water main, cold water subordinate (hereinafter, Is selected either the control of the main operation), in the absorption chiller to control the amount of heat supplied to the regenerator,
[0005]
The reflux cold water temperature t is lower than the second cold water predetermined temperature t2 slightly higher than the first cold water predetermined temperature, and the reflux hot water temperature T is higher than the second hot water predetermined temperature T2 slightly lower than the first hot water predetermined temperature T1. , When the cooling / heating load is small and the transition from a high load state in which at least the reflux cold water temperature t is higher than the second cold water predetermined temperature t2 or the reflux hot water temperature T is lower than the second hot water predetermined temperature T2 Furthermore, when shifting from the cold main operation, the cool main operation is continued to control the combustion amount of the combustor, and when shifting from the warm main operation, the warm main operation is continued to control the combustion amount of the combustor. An operation control method,
By providing the above, the above-described problems of the prior art are solved.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0007]
The example illustrated in FIG. 1 is a double-effect absorption refrigerator as a cold / hot water machine that can circulate and supply cold / hot water to a cooling load and a heating load, with water as a refrigerant and lithium bromide as an absorption liquid. (LiBr) aqueous solution is used.
[0008]
In the figure, 1 is a high temperature regenerator equipped with a gas burner 1B as a heating means, 2 is a low temperature regenerator, 3 is a condenser, 4 is an evaporator, 5 is an absorber, 6 is a low temperature heat exchanger, and 7 is high temperature heat. An exchanger, 8 is a hot water heater, 9 to 11 are absorption liquid pipes, 13 is an absorption liquid pump, 14 to 19 are refrigerant pipes, 20 is a refrigerant pump, and 22 is a circulatory supply of chilled water to a cooling load such as cooling (not shown). A cold water pipe provided with an evaporator heat exchanger 4A in the middle, 23 a cooling water pipe provided with an absorber heat exchanger 5A and a condenser heat exchanger 3A in the middle, and 24 a heating load such as heating (not shown). A hot water pipe provided with a water heater heat exchanger 8A in the middle for circulating hot water, 25 to 28 are on-off valves, 29 and 30 are flow control valves, and these devices are as shown in FIG. This structure itself is well known in the art. .
[0009]
That is, in the absorption chiller / heater configured as described above, when the on-off valves 25, 26, and 27 are closed and the supply of the cooling water to the cooling water pipe 23 is stopped and the gas burner 1B is ignited, the solution in the high-temperature regenerator 1 The refrigerant vapor that has been heated and evaporated and separated from the heated solution enters the water heater 8 through the refrigerant pipe 18, where it is condensed by exchanging heat with water flowing through the water heater heat exchanger 8 </ b> A, and passes through the refrigerant pipe 19. Since circulation returning to the high-temperature regenerator 1 is performed, heat exchange with the refrigerant vapor through the water heater heat exchanger 8A is performed, and heating operation or the like can be performed by circulatingly supplying the heated water, that is, hot water to a heating load (not shown). Yes.
[0010]
On the other hand, the on-off valves 25, 26, and 27 are opened, the on-off valve 28 is closed and the hot water circulation through the hot water pipe 24 is stopped, cooling water is passed through the cooling water pipe 23, the gas burner 1B is ignited, and the high temperature regenerator 1 When the solution is heated, the refrigerant vapor evaporated and separated from the solution in the high temperature regenerator 1 flows into the refrigerant pipe 14, the intermediate absorption liquid is heated and concentrated in the low temperature regenerator 2 and enters the condenser 3, and the refrigerant vapor is generated in the low temperature regenerator 2. The refrigerant vapor evaporated and separated from the intermediate absorption liquid enters the condenser 3 and exchanges heat with the cooling water flowing from the cooling water pipe 23 to the condenser heat exchanger 3A to be condensed and liquefied. The refrigerant enters the evaporator 4 through the refrigerant pipe 15 together with the condensed refrigerant.
[0011]
In the evaporator 4, the refrigerant liquid sprayed onto the evaporator heat exchanger 4 </ b> A by the refrigerant pump 20 evaporates by exchanging heat with water from the cold water pipe 22, and the evaporator heat exchanger 4 </ b> A is generated by the heat of vaporization at this time. The water flowing inside is cooled. Then, the refrigerant vapor evaporated by the evaporator 4 enters the absorber 5 and is absorbed by the absorbing liquid sprayed from above.
[0012]
The absorption liquid of the absorber 5 whose concentration has been reduced by absorbing the refrigerant is sent to the high temperature regenerator 1 through the low temperature heat exchanger 6 and the high temperature heat exchanger 7 by the operation of the absorption liquid pump 13. The absorption liquid that has entered the high-temperature regenerator 1 is heated by the gas burner 1B, and the refrigerant evaporates to enter the low-temperature regenerator 2 via the high-temperature heat exchanger 7 as an intermediate-concentration absorption liquid. Here, the absorbing liquid is heated by the refrigerant vapor flowing from the high-temperature regenerator 1 through the refrigerant pipe 14, and the refrigerant is further evaporated and separated to increase the concentration. The absorbing solution having a high concentration enters the absorber 5 through the low-temperature heat exchanger 6 and is sprayed from above.
[0013]
When the operation of the absorption chiller / heater is performed as described above, the water cooled by the heat of vaporization of the refrigerant through the tube wall of the evaporator heat exchanger 4A in the evaporator 4 is not shown via the chilled water pipe 22. Since it can be circulated and supplied to the cooling load, it can perform cooling operations.
[0014]
Further, while opening the on-off valves 25, 26, and 27, the on-off valve 28 is closed, and while circulating hot water through the hot water pipe 24, the coolant is passed through the cooling water pipe 23 to ignite the gas burner 1 B, and the high-temperature regenerator 1 heats the solution. Then, the refrigerant vapor evaporated and separated from the solution in the high-temperature regenerator 1 is simultaneously supplied to the low-temperature regenerator 2 and the water heater 8 through the refrigerant pipes 14 and 18, so that cooling is performed by circulating and supplying cold water from the cold water pipe 22. An operation and the like can be performed simultaneously with a heating operation in which hot water is circulated and supplied from the hot water pipe 24.
[0015]
31 is a control device provided in the absorption chiller / heater capable of the above-described operation, and a specific configuration example thereof will be described. 32 is provided at the outlet of the evaporator 4 of the chilled water pipe 22. The temperature sensor 40 for detecting the temperature of the cold water flowing into the evaporator 4 after finishing the cooling action, that is, the reflux cold water temperature t, and the water heater 8 inlet of the hot water pipe 24 are provided. An input interface for inputting a temperature signal output from the temperature sensor 41 for detecting the temperature of the hot water flowing into the water 8, that is, the reflux hot water temperature T, and converting the signal into a central processing unit (hereinafter referred to as a CPU) 33; Reference numeral 34 denotes a storage device (hereinafter referred to as ROM) that stores predetermined arithmetic expressions, control programs, and the like. Reference numeral 35 denotes a signal input from the CPU 33 and outputs a required control signal to the gas burner 1B or the like. A power interface 36 is a signal generator (hereinafter referred to as CLOCK) that outputs a signal at a predetermined time, and 37 is a readable / erasable storage device (hereinafter referred to as a temperature signal) output by the temperature sensors 40 and 41. RAM)).
[0016]
For example, the ROM 34 detects the recirculated cold water temperature t by the temperature sensor 40 and the recirculated hot water temperature T by the temperature sensor 41 at predetermined intervals based on the signal output from the CLOCK 36, and detects the recirculated cold water temperature t · The control selection instruction criteria of FIG. 2 for determining and instructing whether to perform the cold main operation or the warm main operation based on the recirculated hot water temperature T and a necessary control program are stored.
[0017]
That is, the CPU 33 operates based on a control program stored in the ROM 34, and when the reflux cold water temperature t and the reflux hot water temperature T are in the region A, the CPU 33 selects the cold main operation unconditionally and sets the reflux cold water temperature t. And when the reflux hot water temperature T is in the region B, the warm main operation is selected unconditionally, and when the reflux cold water temperature t and the reflux hot water temperature T are in the region C, the reflux cold water temperature stored in the RAM 37 t Based on the recirculated hot water temperature T, it is confirmed which of the regions A and B has shifted to the region C. When the region A is shifted, the continuation of the cold main operation is selected. The continuation of operation is selected, and a required control signal is output to the gas burner 1B to perform on / off control, or the amount of combustion is controlled.
[0018]
In the absorption chiller / heater equipped with the control device 31 having the above-described function, even when chilled water and hot water are supplied at the same time and the load of cooling / heating is suddenly reduced, the cold main operation state is changed to the low load operation. When the transition is made, the cold main operation is continued, and when the transition from the warm main operation state to the low load operation is continued, the warm main operation is continued, so the temperature of the cold water and the hot water generated by turning on / off the combustion of the gas burner 1B As a result, frequent switching between the cold main operation and the warm main operation due to hunting is eliminated, and thus a stable cold / hot water simultaneous supply operation can be performed.
[0019]
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit described in the claims.
[0020]
For example, the ROM 34 may store control selection instruction criteria as shown in FIG. 3 instead of the control selection instruction criteria shown in FIG.
[0021]
Also in this case, when the reflux cold water temperature t and the reflux hot water temperature T are in the region A, the cold main operation is selected, and when the reflux cold water temperature t and the reflux hot water temperature T are in the region B, the warm main operation is selected. When the reflux cold water temperature t and the reflux hot water temperature T are in the region C, the cold main operation is continued when entering the region C from the region A, and the warm main operation is continued when entering the region C from the region B. A control program is stored.
[0022]
Further, the RAM 37 stores the reflux cold water temperature t and the reflux hot water temperature T in the areas A and B every predetermined time, and the reflux cold water temperature t and the reflux hot water temperature T shift to the area C. In this case, it can be configured so that it can be directly determined from the stored contents of the RAM 37 whether the region A or B has been transferred.
[0023]
【The invention's effect】
As described above, according to the operation control method of the present invention, even when cold water and hot water are supplied at the same time and the load of cooling / heating is suddenly reduced, the state is changed from the cold main operation state to the low load operation. Sometimes the cold main operation is continued, and when the warm main operation state shifts to the low load operation, the warm main operation is continued. Therefore, the cold water and the hot water generated by turning on / off the combustion of the heating means such as the gas burner The frequent switching between the cold main operation and the warm main operation due to the hunting of the temperature is eliminated, thereby enabling the simultaneous operation of the cold / hot water at a stable temperature.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a device configuration.
FIG. 2 is an explanatory diagram showing an example of control.
FIG. 3 is an explanatory diagram illustrating another control example.
FIG. 4 is an explanatory diagram showing conventional control.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 High temperature regenerator 1B Gas burner 2 Low temperature regenerator 3 Condenser 3A Condenser heat exchanger 4 Evaporator 4A Evaporator heat exchanger 5 Absorber 5A Absorber heat exchanger 6 Low temperature heat exchanger 7 High temperature heat exchanger 8 Hot water heater 8A Hot water heat exchanger 9-11 Absorbing liquid piping 13 Absorbing liquid pump 14-19 Refrigerant piping 20 Refrigerant pump 22 Cold water piping 23 Cooling water piping 24 Hot water piping 25-28 Open / close valve 29/30 Flow control valve 31 Control device 32 Input Interface 33 CPU
34 ROM
35 Output interface 36 CLOCK
37 RAM
40 ・ 41 Temperature sensor

Claims (1)

A regenerator, a condenser, an evaporator, an absorber, and the like are connected to form a circulation cycle of the refrigerant and the absorbing liquid, and water is passed through the evaporator to cool the first cold water at a predetermined temperature t1. A cooling water supply path that circulates cooling water to the cooling load, and a refrigerant liquid that flows in from the regenerator and flows through the container where the refrigerant liquid condensed by heat exchange flows back to the regenerator, and the first hot water has a predetermined temperature T1. And a hot water supply path that circulates and supplies hot water heated to a heating load, and at the time of cold water / hot water simultaneous supply operation, the temperature of water that passes through the vessel for cooling (hereinafter referred to as reflux hot water temperature) T On the basis of the control, the control of the cold water master, the hot water slave (hereinafter referred to as the cold main operation), or the hot water master, the cold water slave (hereinafter referred to as the warm main operation) is selected to control the amount of heat supplied to the regenerator. In absorption chiller / heater
The reflux cold water temperature t is lower than the second cold water predetermined temperature t2 slightly higher than the first cold water predetermined temperature t1, and the reflux hot water temperature T is lower than the second hot water predetermined temperature T2 slightly lower than the first hot water predetermined temperature T1. A transition to a low load state where both the cooling / heating load is high and at least the reflux cold water temperature t is higher than the second predetermined cold water temperature t2 or the high temperature reflux water temperature T is lower than the second predetermined hot water temperature T2 is made. Sometimes, when shifting from the cold main operation, the cool main operation is continued to control the combustion amount of the combustor, and when shifting from the warm main operation, the warm main operation is continued to control the combustion amount of the combustor. A characteristic operation control method.

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