JPS6353449B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner, and more particularly, a medium is circulated by a centrifugal pump in a closed circuit connecting an air conditioner and a heat source device, and the flow rate of the medium is controlled according to the load of the air conditioner. The present invention relates to an air conditioner controlled by a valve.

In a conventional air conditioner, when the medium flow rate is controlled by a flow control valve whose opening degree is controlled according to the load of the air conditioner, when the load becomes smaller, the opening degree of the flow control valve becomes smaller. , the medium flow rate decreases. Therefore, it is desirable to control the rotational speed of the centrifugal pump according to the load in order to save power. However, in general, the rotational speed of this centrifugal pump is not controlled in many cases. Further, as a prior art for controlling the rotation speed, the discharge pressure of a centrifugal pump is detected and the rotation is controlled in accordance with the detected discharge pressure.

In such prior art, the characteristic curve of a centrifugal pump is expressed as shown in FIG. Curves 1, 2, 3, and 4 indicated by solid lines in Fig. 1 represent the characteristic curves of centrifugal pumps, and characteristic curve 1 represents the characteristic curve at the rated state. The characteristic curves are shown respectively.
In addition, curves 5 and 6 shown by broken lines indicate the resistance curves of the pipeline, respectively.Resistance curve 5 is a curve showing the pipeline resistance when the flow control valve is fully open, and resistance curve 6 is a curve when the flow control valve is fully open. This is a curve showing the resistance when the resistance becomes smaller than the time. That is, when the flow rate control valve is fully opened and the centrifugal pump is driven at the rated value, the rated state is represented by the intersection P1 between the characteristic curve 1 and the resistance curve 5.

When the opening degree of the flow control valve becomes small and the resistance curve of the pipeline becomes as shown by reference 6, if the rotation speed of the centrifugal pump is not controlled, the centrifugal pump will have the characteristic curve 1 and the resistance curve. It will be operated at the intersection P2 with 6. Therefore, the pressure increase from point P1 to point P2 is wastefully dissipated as sound and vibration energy. Then the discharge pressure is at point P
1, when the rotational speed of the centrifugal pump is reduced to the value shown by characteristic curve 2, the centrifugal pump reaches the intersection point P3 of characteristic curve 2 and resistance curve 6.
It is possible to save a certain amount of power. In order to keep the discharge pressure constant to some extent, in the extreme case when the flow control valve is fully closed, that is, the medium flow rate is zero, the rotation speed of the centrifugal pump is reduced up to characteristic curve 3 in Fig. 1. can be lowered. However, below that, for example, characteristic curve 4
Since it is not possible to reduce the rotation speed up to this point, power saving cannot be said to be sufficient.

An object of the present invention is to provide an air conditioner that can solve the above-mentioned technical problems and achieve sufficient power saving.

The present invention provides an air conditioner in which a centrifugal pump circulates a medium between an air conditioner and a heat source device, and the flow rate of the medium is controlled by a flow control valve according to the load of the air conditioner. means for detecting the temperature of the blown air; means for controlling the opening of the flow control valve according to the detected temperature of the air blown from the air conditioner; and an opening detector for detecting the opening of the flow control valve; A means for comparing the detected degree of opening with a predetermined value near the fully open value, and a means for lowering the frequency of power supplied to the centrifugal pump when the detected degree of opening is smaller as a result of the comparison. This air conditioner is characterized by:

In addition, the present invention circulates a medium between a plurality of air conditioners and a single heat source unit common to those air conditioners using a centrifugal pump, and adjusts the medium flow rate to each air conditioner according to the load of each air conditioner. In an air conditioner that is controlled by a flow control valve provided for each air conditioner, there is a temperature detector that detects the temperature of the air blown out from each air conditioner, and a temperature detector that detects the temperature of the air blown out from each air conditioner. means for controlling the opening degrees of the flow control valves provided in the corresponding air conditioners, an opening detector for detecting the opening degrees of each flow control valve, and a maximum of each of the detected opening degrees. A signal selector that selects the opening value of , and a maximum opening value selected by the signal selector.
The invention is characterized by comprising means for comparing with a predetermined value near the full opening value, and means for lowering the frequency of the power supplied to the centrifugal pump when the detected opening is smaller as a result of the comparison. It is an air conditioner.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a system diagram of one embodiment of the present invention. A heat medium such as hot water is supplied in parallel from a heat source device 12 to the air conditioners 10 and 11, and the flow rate control valve 1 is activated depending on the load of these air conditioners 10 and 11.
3 and 14 are controlled. Each flow control valve 1
The opening degrees of 3 and 14 are detected by opening degree detectors 15 and 16, respectively.
6 is input to the signal selector 17. The signal selector 17 selects the larger opening degree value among the input signals and inputs it to the proportional regulator 18 . The proportional regulator 18 controls the amount of fuel supplied to the internal combustion engine 19 so that the opening value input from the signal selector 17 becomes a preset value near the fully open value, for example 95%. As a result, the frequency of the generator 20 changes, and the rotational speed of the centrifugal pump 21 changes accordingly.

The heat source device 12 is, for example, a gas absorption type air-conditioning device, and its outlet is connected to a header 23 via a pipe line 22.
connected to. The header 23 is commonly connected to the lines 25, 26 via a line 24 which includes a centrifugal pump, for example a centrifugal pump 21. Conduit 2
5 and 26 are provided with flow control valves 13 and 14, respectively, and are connected to the inlets of air conditioners 10 and 11, respectively. The outlets of the air conditioners 10 and 11 are commonly connected to a conduit 29 via conduits 27 and 28, and this conduit 29
is connected to header 30. The header 30 and the inlet of the heat source device 12 are interconnected by a conduit 32 provided with a pump 31. The headers 23 and 30 are
They are interconnected by a bypass line 34 with a bypass valve 33.

Temperature detectors 35 and 36 are provided at the cold air or hot air outlets of the air conditioners 10 and 11, respectively, and the temperatures detected by these temperature detectors 35 and 36 are sent to temperature controllers 37 and 38. is input. The temperature regulators 37 and 38 control the flow rate control valve 1 so that the temperature of the cold air or hot air becomes a preset temperature according to each input temperature detection value.
Controls the opening degrees of 3 and 14. Each flow control valve 13,
The opening degrees of 14 are detected by opening degree detectors 15 and 16 using potentiometers, respectively, and the opening degree signals detected by these opening degree detectors 15 and 16 are detected by signal selection. The signal is input to the device 17.

The centrifugal pump 21 is driven by electric power supplied from a generator 20, and the generator 20 is driven by the internal combustion engine 19. The signal selector 17 selects the signal with a larger opening among the signals from the opening detectors 15 and 16 and inputs it to the regulator 18 . The regulator 18 is preset with a signal corresponding to a predetermined opening value near full open of the flow rate control valves 13 and 14, for example, 95%, and the signal input from the signal selector 17 is set in advance. If the opening is smaller than the set opening, the rotational speed of the internal combustion engine 19 is reduced; conversely, if the opening is larger than the set opening, the internal combustion engine 1 is rotated.
Increase the rotation speed of 9.

In such an air conditioner, the air conditioner 1
The load on flow control valves 13, 1 becomes lower.
4 becomes small, the rotational speed of the internal combustion engine 19 is controlled to be low. Correspondingly, the frequency and voltage of the electric power supplied from the generator 20 to the centrifugal pump 21 are reduced, and the rotational speed of the centrifugal pump 21 is reduced. As a result, the discharge pressure of the centrifugal pump 21 decreases, and the air conditioner 1
When the flow rate of the medium flowing through the pumps 0 and 11 becomes too low compared to the load, the flow rate control valves 13 and 14 become larger, thereby increasing the rotation speed of the centrifugal pump 21 in accordance with the rotation speed of the internal combustion engine 19. . Therefore, the entire control system can be balanced at an optimal point. Contrary to the above, optimal control is similarly performed even when the load on the air conditioners 10, 11 increases.

The characteristics of the centrifugal pump 21 in the present air conditioner will be explained with reference to FIG. Curves 40, 41, and 42 shown as solid lines in FIG. 3 indicate the characteristic curves of the centrifugal pump 21, and the characteristic curve 40 indicates the rated state. Also, a curve 43 indicated by a broken line,
Reference numerals 44 and 45 indicate resistance curves, and resistance curve 43 indicates a state in which the flow rate control valves 13 and 14 are fully open.

In an ideal state in which the load fluctuations of the air conditioners 10 and 11 are almost the same, the opening degrees of the flow control valves 13 and 14 are maintained close to fully open, so the resistance curve remains approximately at reference 43, and the load decreases. As a result, the characteristic curve of the centrifugal pump 21 moves from reference numeral 40 to 41 and 42, and the operating state moves accordingly from point P5 to P6 or P7. Such changes in operating conditions are the same even when there is a single air conditioner. However, in reality, when there are multiple air conditioners 10 and 11 as shown in FIG. It deviates slightly from curve 43. Therefore, the operating state is also as shown in the positions P8 and P9. In this way, it is not necessary to maintain the discharge pressure at the same pressure as the operating state at the rated time, that is, the position shown by point P5, so that the centrifugal pump 2
Accordingly, the power can be reduced and sufficient power savings can be achieved.

Note that when there are a plurality of air conditioners and the load on each air conditioner varies greatly, the opening degree of each flow control valve may vary greatly as shown by the resistance curve 45. The operating points in this case are points P10 and P11
It will be in the position shown. In extreme cases,
If any one of the plurality of air conditioners is operated at 100% load, only that air conditioner requires the same discharge pressure as the position shown at point P5, so it will be operated at point P10. In this case, it is equivalent to the discharge pressure control of the prior art, but if the load of the air conditioner with the maximum load is reduced even a little, the point P11 is approached, so that further power saving can be achieved.

In the above-described embodiment, the air conditioners 10 and 11 are described as two units, but there may be three or more air conditioners, or there may be one air conditioner. Note that when there is only one air conditioner, the signal selector 17 can be omitted. Furthermore, a commercial power source and an inverter may be used instead of the internal combustion engine 19 and the generator.

As described above, according to the present invention, the rotation speed of the centrifugal pump is adjusted while keeping the opening degree of the flow control valve close to the fully open value, so that the power consumed can be optimized depending on the load of the air conditioner. It is possible to achieve sufficient power saving.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a characteristic curve of a centrifugal pump in the prior art, FIG. 2 is a system diagram of an embodiment of the present invention, and FIG. 3 is a diagram showing a characteristic curve of the centrifugal pump of FIG. 2. 10, 11... Air conditioner, 12... Heat source machine, 13, 1
4...Flow rate control valve, 15, 16...Opening degree detector, 17
...signal selector, 18...regulator, 21...centrifugal pump.

Claims (1)

[Scope of Claims] 1. An air conditioner in which a centrifugal pump circulates a medium between an air conditioner and a heat source device, and the flow rate of the medium is controlled by a flow control valve according to the load of the air conditioner, comprising: means for detecting the temperature of the air blown from the air conditioner; means for controlling the opening degree of the flow control valve according to the detected temperature of the air blown from the air conditioner; and an opening detection means for detecting the opening degree of the flow control valve. means for comparing the detected degree of opening with a predetermined value near the fully open value; and means for reducing the frequency of power supplied to the centrifugal pump when the detected degree of opening is smaller as a result of the comparison. An air conditioner characterized by comprising: 2 A centrifugal pump circulates the medium between multiple air conditioners and a single heat source device common to those air conditioners, and the medium flow rate is set for each air conditioner according to the load of each air conditioner. In an air conditioner that is controlled by a flow rate control valve, there is a temperature detector that detects the temperature of the air blown out from each air conditioner, and a temperature sensor that detects the temperature of the air blown out from the air conditioner. means for controlling the opening degrees of the flow control valves provided in the air conditioner; an opening detector for detecting the opening degrees of each flow control valve; and a maximum opening value among the detected opening degrees. A signal selector that selects the maximum opening value selected by the signal selector,
The invention is characterized by comprising means for comparing with a predetermined value near the full opening value, and means for lowering the frequency of the power supplied to the centrifugal pump when the detected opening is smaller as a result of the comparison. Air conditioner.