JPH0355748B2 - - 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.

Conventionally, the system is operated so as to supply a constant flow rate of hot water to the hot water load, so when the hot water load is reduced, the temperature difference between the inlet and outlet of the hot water load becomes small. Therefore, if you try to control the hot water temperature given to the hot water load at a constant level, the temperature of the hot water returning from the hot water load to the absorption chiller increases as the hot water load decreases, which causes the absorber temperature to rise. Therefore, the efficiency of the cold water side is significantly reduced. Furthermore, if the temperature of the hot water returned to the absorption chiller is controlled to be constant, the temperature at which it is applied to the hot water load will decrease, and the utility value of the hot water will therefore decrease.

An object of the present invention is to solve the above-mentioned technical problems and provide an absorption type water chiller/heater that maintains efficiency on the cold water side by controlling the flow rate of hot water and prevents a decrease in the utility value of hot water. .

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 chilled water cooled by an evaporator 2 is given to an air conditioner 15 via a chilled water circulation circuit 11, and an 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. In the hot water circulation circuit 16, 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 regulator 36, 37, 38 are given to a signal selector 32, which selects the signal from each temperature regulator 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 regulators 36 and 37 that results in 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 indicated by reference numeral a is sent from the cold water temperature regulator 36, a signal indicated by reference numeral b is sent from the hot water temperature regulator 37, and a signal indicated by reference numeral b is sent 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 of the signals a and c is the signal a.
Select. Therefore, the signal a is selected and outputted from the signal selector 32, 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 20 mA, and is fully open when the output signal is 4 mA.

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 is possible. is performed automatically and continuously. Therefore, even if each load fluctuates, it is possible to stably and adequately cope with the fluctuation. Moreover, 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 the 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 feeding temperature when hot water is flowed at a constant flow rate as in the past is shown by the dashed line in FIG. 3, and as the hot water load decreases, the hot water feeding 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, part of which is given as the amount of heat Q4 to the hot water load, and the remaining amount of heat Q5 is given to the dummy load. will be given to By radiating heat to the simulated load in this way, it becomes possible to operate the absorption type water chiller/heater 1 over a wide range shown by diagonal lines in FIG.

Although the embodiments described above use a dual-effect absorption refrigerator, the invention can be practiced in conjunction with other absorption refrigerators. Further, instead of the heater 20, a hot water supply heat exchanger may be provided. Furthermore, the heat given to the high temperature regenerator 5 does not have to be the combustion heat of fuel, but may be supplied with electric power or high temperature waste gas. Note that in the case of energizing with electric power, a means for controlling the amount of energizing power may be provided in place of the flow rate control valve 9.

As described above, according to the present invention, the hot water flow rate in the hot water circulation circuit is controlled so that the temperature difference before and after the hot water load is almost constant, so the temperatures before and after the hot water load are almost constant and stable. Even if the hot water load is reduced, the efficiency of the cold water side will not decrease, and the hot water will remain at a relatively high temperature, so its utility value will not decrease.

Further, according to the present invention, the hot water return temperature, cold water inlet temperature, and 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. So,
Control switching is performed automatically and continuously, and sufficiently stable operation can be performed in response to load fluctuations, and the regenerator's ability can be maximized.

[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 controller 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 the hot water load and the cold water load. 1...Double effect absorption refrigerator, 2...Evaporator,
3...Absorber, 4...Condenser, 5...High temperature regenerator, 11...Cold water circulation circuit, 15...Air conditioner, 1
6...Hot water circulation circuit, 20...Heater, 21...
Flow rate control valve, 23...Temperature difference regulator, 24, 34
...Temperature detector.

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 type water chiller/heater including a cold water circulation circuit, comprising: a flow 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 each of the temperature detectors. a temperature difference regulator that responds to the output of the hot water load and controls the flow rate control valve so that the temperature difference therebetween becomes a preset value; and a temperature sensor that responds to the output of the temperature detector that detects the temperature at the outlet of the hot water load. , a hot water temperature regulator that outputs a signal that increases the amount of heat input to the regenerator in the absorption chiller in response to a decrease in the hot water return temperature from the hot water load; A chilled water temperature regulator that outputs a signal that increases the amount of heat input to the regenerator as the temperature at the inlet of the chilled water increases; and the amount of heat input to the regenerator as the temperature inside the regenerator decreases. a regenerator temperature controller that outputs a signal that increases
The signals from the hot water temperature regulator and the cold water temperature regulator are compared to select the signal that increases the amount of heat input, and the selected signal and the signal from the regenerator temperature regulator are compared to select the signal that increases the amount of heat input. An absorption type characterized in that it includes a signal selector that selects and outputs a signal that requires a smaller amount of heat input, and means that controls the amount of heat input to the regenerator in accordance with the output signal from the signal selector. Hot and cold water machine.