JPH0355746B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absorption chiller/heater, and more particularly to an absorption chiller in which hot water is heated and taken out by an absorber and a condenser, and cold water is cooled and taken out by an evaporator. Regarding cold/hot water machines.

When switching between a conventional absorption type water chiller/heater and a mainly hot water load or a mainly cold water load, the operator should switch between mainly hot water and cold water depending on the hot water load and cold water load. Alternatively, when the switching is to be performed automatically, the temperature of the cold water and the hot water are compared and the switching is performed using a changeover switch or the like. However, in the former case, if the load is stable, switching operations can be performed seasonally, but if the load fluctuates throughout the day, it is necessary to adequately respond to the load fluctuations. I can't. In the latter case, although it is possible to cope with load fluctuations to a certain extent, the switching operation becomes discontinuous and stable control cannot be performed. Therefore, the overall efficiency of both is inferior. Furthermore, in the heat pump operation of an absorption chiller, the water that is used as cooling water in a normal refrigeration cycle becomes hot water and raises the temperature level, so the amount of heat input to the regenerator is the maximum rated amount in the normal refrigeration cycle. It can be kept lower than the point. For example, when using a dual-effect absorption chiller, if the temperature at the inlet and outlet of the hot water applied to the hot water load is set to 40 to 45 degrees Celsius, the amount of heat input must be 70 to 80% of the rated point for regeneration. The temperature and pressure of the container may become abnormally high. Therefore, conventionally, a so-called limiter or the like is used to prevent the amount of heat input from exceeding 70 to 80%.
However, when such a setting is made, the maximum capacity of the absorption refrigerating machine is inferior because the upper limit value is set on the safe side.

The present invention solves the above-mentioned technical problem, and enables stable operation in response to load fluctuations by automatically and almost continuously switching control between mainly hot water load and cold water load. The purpose of the present invention is to provide an absorption type water chiller/heater that enables the following functions.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram of an embodiment of the present invention.
In this absorption chiller/heater, a double-effect absorption chiller 1 functions as a heat pump, and cold water cooled by an evaporator 2 is given to a heater 15 via a chilled water circulation circuit 11, and the absorber 3 and the hot water heated by the condenser 4 are supplied to the heater 20 via the hot water circulation circuit 16.

The dual-effect absorption refrigerator 1 includes an evaporator 2, an absorber 3, a high-temperature regenerator 5, a low-temperature regenerator 6, a condenser 4, heat exchangers 7 and 8, and the like. Fuel, such as city gas, is supplied to the high temperature regenerator 5 through a pipe 10 equipped with a flow control valve 9, and its combustion heat is used as a drive heat source for the dual-effect absorption refrigerator 1.

In the chilled water circulation circuit 11, the inlets of each air conditioner 15 are commonly connected to the chilled water supply header 13, and the outlets of each air conditioner 15 are commonly connected to the chilled water return header 14. The cold water return header 14 and one end of the coil 2a provided in the evaporator 2 are connected to the pump 1.
connected by a conduit 11a comprising 2,
The other end of the coil 2a and the cold water supply header 13 are connected by a conduit 11b. In such a cold water circulation circuit 11, the cold water cooled by the coil 2a is supplied from the cold water supply header 13 to each air conditioner 15 and left to cool, and the water after being left cool is circulated to the coil 2a by the pump 12. and cooled.

In the hot water circulation circuit 16, the inlets of the heaters 20 are commonly connected to the hot water supply header 18, and the outlets of the heaters 20 are commonly connected to the hot water return header 19. The hot water return header 19 is connected to the pump 1
7 to the coil 3a in the absorber 3. This coil 3a is connected to the coil 4a in the condenser 4, and the coil 4a
is connected to the hot water supply header 18 via a conduit 16b. The hot water circulation circuit 16 smell is caused by the coil 3
The hot water heated in a and 4a is supplied to the hot water supply header 18.
The water is supplied from the hot water return header 19 to each heater 20 to radiate heat, and the water after the heat is radiated is circulated from the hot water return header 19 to the coil 3a by the pump 17.

A bypass pipe 40 is connected to the middle of the pipe 16 a in the hot water circulation circuit 16 , and the bypass pipe 40 and the pipe 16 a are connected via a three-way valve 25 . The bypass pipe line 40 is provided in the heat exchanger 28 as a hot water simulated load, and the heat exchanger 28 is equipped with a cooling tower 29 and a pump 3.
A cooling water circulation circuit 41 including 0 in order is connected. In this cooling water circulation circuit 41 , heat radiated from the bypass pipe 40 within the heat exchanger 28 is radiated in the cooling tower 29 .

In the chilled water circulation circuit 11, a chilled water outlet temperature detector 35 is provided in the middle of the pipe line 11b between the coil 2a and the chilled water supply header 13, and a detection signal from this chilled water outlet temperature detector 35 is used to adjust the chilled water temperature. The signal is input to the device 36. Also, hot water circulation circuit 16
A first hot water return temperature detector 22 is provided in the middle of the pipe 16a, and a detection signal from this first hot water return temperature detector 22 is sent to the hot water temperature controller 3.
7 is input. Further, the high temperature regenerator 5 is provided with a temperature detector 31, and a detection signal from the temperature detector 31 is input to a regenerator temperature controller 38. The signals from each temperature detector 36, 37, 38 are given to a signal selector 32, which selects the signal from each temperature detector 36, 37, 38, and uses the selection result as Based on conduit 1
The opening degree of the flow control valve 9 at 0 is adjusted.

In the cold water temperature regulator 36, as shown in FIG. 2, the output signal is increased proportionally as the cold water outlet temperature increases. In addition, the set value of the cold water outlet temperature is set to, for example, 9°C.
A proportional band is set within a range of ±1°C. In the hot water temperature regulator 37, as shown in FIG. 2, the output signal increases proportionally as the hot water return temperature increases. The set value of this hot water return temperature is set to 39℃, for example, and the proportional band is ± the set value.
The temperature is chosen to be 2°C. Furthermore, regenerator temperature controller 3
8, the output signal is increased proportionally, for example, as the temperature of the regenerator decreases, as shown in FIG. For example, the set value of the regenerator temperature is
155℃ is selected, and the proportional band is selected to be within the set value ±5℃.

The signal selector 32 includes a high selector 32a and a low selector 32b, as shown in FIG. 2. The high selector 32a selects the signal from the temperature detectors 36 and 37 that produces a larger combustion amount. This selected signal is transmitted to the regenerator temperature controller 38 at the next low selector 32b.
The signal with the smaller combustion amount is selected and outputted as a combustion control signal, thereby controlling the flow rate control valve 9. In other words, the combustion amount in the high-temperature regenerator 5 is controlled by the signal of the larger of the required combustion amounts on the cold water side and the hot water side when the set value of the high-temperature regenerator 5 is sufficiently lower than, for example, 155°C. controlled. Furthermore, even if the combustion demand from the cold water side or the hot water side is large, the temperature of the high-temperature regenerator 5 is in a high state exceeding 155°C, and the regenerator temperature controller 38
If the output signal is smaller than each of the required combustion amounts, the opening degree of the flow rate control valve 9 is controlled by the signal from the regenerator temperature controller 38. That is,
The signal selector 32 will operate as a combustion amount limiter.

Referring again to FIGS. 2 1 to 2 4, a signal from the cold water temperature regulator 36 is indicated by reference numeral a, a signal indicated by reference numeral b from the hot water temperature regulator 37, and a signal indicated by reference numeral b from the regenerator temperature regulator 38. Assume a state in which signals indicated by reference numeral c are respectively input to the signal selector 32. Such a state is an operating state in which the chilled water load is the main component. In this way, the high selector 32a of the signal selector 32 selects the larger signal a of the output signals a and b, and the low selector 32
In b, the smaller signal a is selected between signals a and c. Therefore, the signal a from the signal selector 32
is selected and output, and the opening degree of the flow rate control valve 9 is controlled by this signal a. Note that the flow rate control valve 9
is fully open when the output signal is 20mA, and fully closed when the output signal is 4mA.

In this way, by selecting the signals from the temperature controllers 36, 37, and 38 using the signal selector 32 and adjusting the opening degree of the flow rate control valve 9, switching between control mainly for cold water load and mainly for hot water load can be performed. is performed automatically and continuously. Therefore, even if each load fluctuates, it is possible to stably and adequately cope with the fluctuation. Furthermore, since the upper limit of the combustion amount is controlled by detecting the temperature of the high temperature regenerator 5, the combustion amount in the high temperature regenerator 5 can be controlled to almost the maximum capacity. Furthermore, if the liquid temperature in the high-temperature regenerator 5 is low at the start of operation, the liquid can be burned up to the rated point of the normal refrigeration cycle, making it possible to shorten the warm-up time.

A second hot water return temperature detector 34 is provided in the middle of the pipe line 16a in the hot water circulation circuit 16,
A detection signal from the hot water return temperature detector 34 is input to the temperature difference regulator 23. Further, a hot water supply temperature detector 24 is provided in the middle of the pipe line 16b, and the detected value by this hot water supply temperature detector 24 is given to the temperature difference regulator 23. Furthermore, conduit 1
A hot water flow rate control valve 21 is provided in the middle of 6a, and the opening degree of this hot water flow rate control valve 21 is controlled by a temperature difference regulator 23. Moreover, the temperature difference regulator 23
controls the opening degree of the hot water flow rate control valve 21 so that the detected temperature difference between the hot water return temperature detector 34 and the hot water sending temperature detector 24 is constant.

Referring to FIG. 3, for example, the temperature difference regulator 23
In this case, the temperature difference Δt is set to 4°C, and the proportional band is set to 2°C. Moreover, if the flow rate control valve 9 is controlled by the hot water return temperature and its proportional band is set to 2°C, the hot water feed temperature for the hot water load is shown by straight line A in Fig. 3, and the hot water return temperature is shown by straight line B. Further, the hot water flow rate is shown by straight line C in FIG. 32. As is clear from FIG. 3, both the hot water sending temperature and return temperature are relatively stable, and the efficiency on the cold water side is maintained sufficiently.
Moreover, since the hot water temperature remains relatively high, it has sufficient utility value. For reference, the hot water feed temperature when hot water is flowed at a constant flow rate as in the past is shown by the dashed line in Figure 3, and as the hot water load decreases, the hot water feed temperature decreases. .

Referring again to FIG. 1, signals from cold water temperature regulator 36 and hot water temperature regulator 37 are input to signal comparator 33. The signal comparator 33 compares the magnitudes of both signals, distinguishes whether the load is mainly cold water or hot water, and inputs a signal for controlling the three-way valve 25 to the regulator 27. Further, the regulator 27 is given a detection signal from a temperature detector 26 provided downstream of the three-way valve 25 in the conduit 16a.

The regulator 27 controls the three-way valve 2 when the signal from the signal comparator 33 indicates hot water main operation.
5 to prevent hot water from flowing into the bypass pipe line 40. In addition, in the case of cold water load-based operation, the three-way valve 25 is controlled according to the temperature detected by the temperature detector 26, and part of the hot water radiates heat through the heat exchanger 28 as a simulated load. It should be noted that when the pump 30 in the cooling water circulation circuit 41 is in hot water load-based operation and the three-way valve 25 begins to open to start flowing hot water into the bypass pipe 40,
It is driven by a signal from regulator 27. This prevents unnecessary operation of the pump 30.

By dissipating heat through the heat exchanger 28 as a simulated load in this manner, the heat balance of the absorption type water chiller/heater 1 as a whole becomes as shown in FIG. 4. That is, the amount of heat input Q1 to the high-temperature regenerator 5 and the amount of heat input Q2 to the evaporator 2 become the total amount of heat input Q3, a part of which is given to the hot water load Q4, and the remaining amount of heat Q5 is given to the simulated load. It will be given to you. By dissipating heat to the simulated load in this manner, it becomes possible to operate the absorption type water chiller/heater 1 over a wide range indicated by diagonal lines in FIG.

Although a dual-effect absorption refrigerator was used in the embodiments described above, the present invention can also be implemented in conjunction with other absorption refrigerators. Moreover, a heat exchanger for hot water supply may be provided in place of the coil 20. Furthermore, the heat supplied to the high temperature regenerator 5 does not have to be the combustion heat of the fuel, and may be supplied by electric power or by introducing high temperature waste gas. In addition, when using electric power,
Instead of the flow rate control valve 9, a means for controlling the amount of power energization may be provided.

As described above, according to the present invention, the hot water return temperature, the cold water inlet temperature, and the temperature inside the regenerator are compared by the signal selector, and the amount of heat input to the regenerator is controlled depending on whether the hot water load is the main load or the cold water load is the main operation. As a result, control switching is performed automatically and continuously, allowing sufficiently stable operation in response to load fluctuations and maximizing the capacity of the regenerator. .

Furthermore, according to the present invention, since a simulated load for heat dissipation is used, as described in relation to FIG. This is an excellent effect of the present invention that cannot be achieved with the prior art.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is a diagram for explaining the operation of each temperature detector 36 to 38 and signal selector 32, and FIG. 3 is for explaining variable flow rate control of hot water. FIG. 4 is a diagram showing the heat balance, and FIG. 5 is a graph showing the operating range corresponding to hot water load and cold water load. 1...Double effect absorption refrigerator, 2...Evaporator,
3...Absorber, 4...Condenser, 5...High temperature regenerator, 9...Flow control valve, 11...Cold water circulation circuit,
15... Heater, 16... Hot water circulation circuit, 20...
...Heater, 22,35...Temperature detector, 32...
Signal controller, 36... Cold water temperature controller, 37...
Hot water temperature regulator, 38...Regenerator temperature regulator.

Claims (1)

[Scope of Claims] 1. A hot water circulation circuit that heats hot water using an absorber and a condenser of an absorption chiller and supplies it to a hot water load, and a hot water circulation circuit that cools cold water using an evaporator and supplies it to a cold water load. An absorption chiller/heater comprising a cold water circulation circuit, comprising: a flow rate control valve provided in the hot water circulation circuit; a temperature detector for detecting temperatures at the inlet and outlet of the hot water load, respectively; and an outlet of the hot water load. a hot water temperature that outputs a signal that increases the amount of heat input to the regenerator in the absorption chiller in response to the output of a temperature detector that detects the temperature at a regulator; a chilled water temperature regulator that outputs a signal to increase the amount of heat input to the first-stage regenerator in response to an increase in the temperature of the chilled water inlet to the chilled water load in the chilled water circulation circuit; and a temperature in the regenerator. The regenerator temperature controller outputs a signal that increases the amount of heat input to the regenerator as the temperature decreases, and the signals from the hot water temperature controller and cold water temperature controller are compared to increase the amount of heat input in the previous period. a signal selector that selects a signal that makes the amount of heat input smaller by comparing the selected signal and the signal from the regenerator temperature controller, and selects and outputs the signal that makes the amount of heat input smaller; means for controlling the amount of heat input to the regenerator according to the output signal from the selector; a hot water simulated load for heat radiation interposed between the hot water load of the hot water circulation circuit and the absorber; and hot water on the hot water load side. a three-way valve that switches and guides the water to the absorber with or without a simulated hot water load, a temperature detector that detects the hot water temperature downstream of the three-way valve, a hot water temperature regulator, a cold water temperature regulator, and The three-way valve responds to each signal from the temperature sensor for detecting hot water temperature on the downstream side, and when hot water-based operation is performed, the three-way valve prevents hot water from flowing into the simulated load, and when cold water-based operation is performed, the three-way valve prevents hot water from flowing into the simulated load. An absorption chiller/heater comprising: a controller that controls a part of the hot water to be directed to a simulated load using a three-way valve according to the temperature of the hot water on the downstream side.