JPH0275841A - Multi-room type air-conditioning machine - Google Patents

Abstract

PURPOSE:To recover the condition of continued operation to a normal condition in an early period even when another indoor unit is started or stopped additionally during the operation of an indoor unit by controlling the opening degree of an electronic expansion valve based on the inlet port side pressure and/or the outlet port side temperature or pressure of the electronic expansion valve. CONSTITUTION:In a plurality of indoor units 2, the inlet port pressure of an electronic expansion valve 9 is detected by a pressure sensor 8 while a temperature at the intermediate position between the electronic expansion valve 9 and an indoor heat exchanger 11 or the outlet port temperature of the electronic expansion valve 9 is detected by a temperature sensor 10. In this case, the flow of refrigerant in respective indoor units 2 is in stationary condition and the present opening degree V1 of the electronic expansion valve 9 of themselves is stored in respective control units 15. When another indoor unit 2 is started or an arbitrary indoor unit 2 is stopped additionally, the indoor unit 15 of the indoor unit 2, whose operation is to be continued, receives a signal, showing that there is additional starting or stopping, from an outdoor unit 1. The control amount DELTAV of the opening degree of the electronic expansion valve 9 is obtained in accordance with the signal and a driving circuit controls the electronis expansion valve 9 in accordance with the control amount DELTAV.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multi-room air conditioner comprising a plurality of indoor units connected to one outdoor unit.

[Conventional technology]

FIG. 4 is a block diagram showing a conventional multi-room air conditioner. In the figure, 1 is an outdoor unit, and 2 is a plurality of indoor units connected in parallel to the outdoor unit 1.

In the outdoor unit 1, 3 is a compressor that compresses low-pressure refrigerant gas to high pressure, 4 is an outdoor heat exchanger that converts the high-pressure refrigerant gas from the compressor 3 into high-pressure refrigerant liquid, and 5 is a high-pressure refrigerant liquid that is transferred to the indoor unit 2. It is an achievator that supplies the low-pressure refrigerant gas from the indoor unit 2 to the compressor 3. Reference numeral 6 indicates a liquid-side main pipe for delivering high-pressure refrigerant liquid, and 7 indicates a branch pipe that branches from the liquid-side main pipe 6 to the indoor unit 2. In indoor unit 2, 9
The high-pressure refrigerant liquid sent through the branch pipe 7 is heated to a low temperature.
Electronic expansion valve for adiabatic expansion to low pressure, 10 is electronic expansion valve 9
a temperature sensor that detects the temperature of the refrigerant liquid output from the
1 is an indoor heat exchanger that heat-exchanges the refrigerant liquid supplied from the electronic expansion valve 9 and converts it into low-pressure refrigerant gas; 12 is a temperature sensor that detects the temperature of the low-pressure refrigerant gas output from the indoor heat exchanger 11; 13 is a temperature sensor 1G.

A control device 12 controls the opening degree of the electronic expansion valve 9 based on the detected temperature;

FIG. 5 is a block diagram showing the configuration of the control device 13,
In the figure, 20 is a CPU, 21 is a program memory of the CPU 20, 22 is a data memory that sends and receives data to and from the CPU 20, 23 is an analog input conversion circuit to which temperature detection signals from the temperature sensors 10 and 12 are supplied, and 25
27 is a drive circuit that drives the electronic expansion valve 9, and 27 is a CPU 20.
This is an internal bus that connects each circuit.

Next, the operation will be explained.

In the outdoor unit 1, the high-pressure refrigerant liquid output from the outdoor heat exchanger 4 is transferred to an akinimulator 5 and a liquid side main pipe 6.
and is supplied to each indoor unit 2 through branch piping T.

In the indoor unit 2, the supplied high-pressure refrigerant liquid is sent to the indoor heat exchanger 11 through the electronic expansion valve 9, where a heat exchange action is performed to cool the room. The low-pressure refrigerant gas converted by the indoor heat exchanger 11 is returned to the outdoor unit 1 through the gas side piping 14, and is converted to high-pressure refrigerant gas by the compressor 3 via the akinimulator 5, and then transferred to the outdoor heat exchanger 4. The refrigerant is then converted back into high-pressure refrigerant liquid.

During operation, each indoor unit 2 individually detects the inlet temperature of the indoor heat exchanger 110 at fixed time intervals with the temperature sensor 10, detects the outlet temperature with the temperature sensor 12, and sends the temperature detection signal to the control device 13. .

The above temperature detection signal is transmitted to the analog input conversion circuit 2 in Fig. 5.
3 and the internal bus 27 to the CPU 20. C
In order to adjust the flow rate of refrigerant passing through the indoor heat exchanger 11, the PU 20 calculates the opening degree of the electronic expansion valve 9 based on the following calculation.

If △T≧T1, open the electronic expansion valve 9 to a certain opening T
If 2≦ΔT×T1, the opening degree of the electronic expansion valve 9 is fixed.

If ΔT≦T2, the electronic expansion valve 9 is closed by a certain opening.

Here, △T: Temperature difference between the entrance and exit of the indoor heat exchanger 11 △T=
To-TI To: Output temperature T of the indoor heat exchanger 11! Two-room heat exchanger 110 inlet temperature Tl + T2: Set value The drive circuit 25 controls the opening degree of the electronic expansion valve 90 according to the above calculation result.

[Problem to be solved by the invention]

Since the conventional multi-room air conditioner is configured as described above, when multiple indoor units 2 are operated,
When another indoor unit 2 is additionally started or when a certain indoor unit 2 stops, it continues to operate and the flow rate of refrigerant passing through the indoor unit 2 changes, which disturbs the refrigerant distribution and makes it inappropriate. There were issues such as difficulty in stabilizing operation quickly.

This invention was made to solve the above-mentioned problems, and when one or more indoor units are being operated and another indoor unit is additionally started,
And if any indoor unit is stopped while multiple indoor units are in operation, the operating state of the indoor unit that continues to be operated after that is the operation state before the above additional startup or stop. It is an object of the present invention to provide a multi-room air conditioner in which the flow rate of refrigerant to an indoor heat exchanger is controlled so that the condition can be quickly recovered.

[Means to solve the problem]

The multi-room air conditioner according to the present invention is provided with a pressure sensor that detects the pressure on the inlet side of the electronic expansion valve in the indoor unit, and a temperature sensor or a pressure sensor that detects the temperature or pressure on the outlet side of the electronic expansion valve, The opening degree of the electronic expansion valve is controlled based on detection signals from these sensors.

[Function] The multi-room air conditioner according to the present invention controls the opening degree of the electronic expansion valve based on the inlet side pressure and the outlet side temperature or pressure of the electronic expansion valve, so that the opening degree of the electronic expansion valve is controlled based on the inlet side pressure and the outlet side temperature or pressure of the electronic expansion valve. If there is an additional start or stop, the operating state of the indoor unit that continues to be operated will promptly return to the normal state.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In FIGS. 4 and 2, parts corresponding to those in FIGS. 4 and 5 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 1, 8 is a pressure sensor that detects the pressure of the refrigerant liquid supplied to the electronic expansion valve 9 through the branch pipe 7. Therefore, the pressure on the input side of the electronic expansion valve 9 is detected by the pressure sensor 8, and the temperature on the outlet side of the electronic expansion valve 9 is detected by the temperature sensor 10. A control device 15 controls the opening degree of the electronic expansion valve 9 based on the pressure detected by the pressure sensor 8 and the temperature detected by the temperature sensor 10.

In FIG. 2, reference numeral 26 indicates a signal indicating the start or stop of another indoor unit 2, which is sent from the outdoor unit 1. The other parts of this control device 15 have the same structure as the control device 13 shown in FIG.

Next, the operation will be explained.

As mentioned above, the indoor unit 2 cools the room by exchanging heat with the indoor heat exchanger 11 via the electronic expansion valve 9 with the refrigerant liquid supplied from the outdoor unit 1 through the liquid side main pipe 6 and the branch pipe 7. That's exactly what I did. Here, the flow rate of refrigerant passing through the electronic expansion valve 9 is determined by the pressure difference between the inlet and outlet of the electronic expansion valve 9 and the passage area of the valve.

That is, the refrigerant flow rate GR passing through the electronic expansion valve 9 is cR=
kl@A・Cr・・・・・・・・・・・・・・・・・・
...(1) Here, △p=pL-p2 1: Proportionality constant A: Valve passage area Pl: Electronic expansion valve 90 inlet pressure P2: Electronic expansion valve 9 outlet pressure Note that P2 is the refrigerant Since it is a two-phase liquid and gas, a value converted from the saturation temperature detected by the temperature sensor 10 is used. Also, the passage area A of the valve and the opening degree V of the valve are V = l(2@A ・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・(
2) k2: Expressed as a proportionality constant. Therefore, from the above fl), +21 formula, the refrigerant flow rate GR is: GR=85 f1 ・・・・・・・・・・・・・・・・・・
・・・・・・・・・(3) K=is expressed as 1 and 2. When multiple indoor units 2 connected in parallel are operating, if another indoor unit 2 is additionally started or if any indoor unit 2 is stopped, the valve opening degree V remains constant. If this continues, ΔP will change, and therefore GR will change, so the operating state of the indoor unit 2 that continues to be operated will change. Therefore, in order to reduce the rate of change in the operating state and restore the original normal operating state in a short time, the electronic expansion valve should be installed so that the refrigerant flow rate before and after the above-mentioned additional start or stop is equal. What is necessary is to adjust the opening degree V of 9. Adjustment amount ΔV of the opening degree V of this valve
is calculated using the following formula.

GRI = K-vt conflict δ possible Ga2 = K-V2"4 possible cat == Ga2, so vle, /"2S possible = v2・f] bow △v=vl -vl △V=V1" (1- ) ””””””□”” (4) Here, Ga1: Refrigerant flow rate before change GR2: Refrigerant flow rate after change vl: Valve opening degree before change vl: Valve opening degree after change △P1; Difference in inlet and outlet pressures of the electronic expansion valve 9 before change ΔP2: Difference in inlet and outlet pressures of the electronic expansion valve 9 after change Next, the actual control operation will be explained.

1 and 2, in the plurality of indoor units 2, the electronic expansion valve 90 is opened at predetermined time intervals during operation.
The inlet pressure is detected by the pressure sensor 8, and the temperature between the electronic expansion valve 9 and the indoor heat exchanger 11, that is, the electronic expansion valve 9 is detected.
The temperature sensor 10 detects the outlet temperature of the sensor 10 , and the detection signals are inputted to the control device 15 . At this time, the flow of refrigerant in each indoor unit 2 in operation is in a steady state, and the current valve opening degree v1 of its own electronic expansion valve 9 is stored in each control device 15. In this state, if another indoor unit 2 is additionally started or if any indoor unit 2 is stopped, the indoor unit 2 that continues to operate
The outdoor unit 1 inputs a signal 26 to the control device 15 indicating that the additional start or stop has occurred. In response to this, the control device 15 stops inputting the pressure and temperature detection signals, and holds the pressure and temperature for a predetermined time T just before the signals 26 are input. After time T has elapsed, pressure and temperature detection signals are input again. Next, signal 26
The temperature and pressure held just before input, and the time T
After the elapse of , the control amount △V of the opening degree of the electronic expansion valve 9 is obtained by calculating the equations (1) to (4) above based on the first input pressure and temperature, and this △ The drive circuit 25 controls the electronic expansion valve 9 in accordance with V.

FIG. 3 is a flowchart of the control device 15 for performing the above-mentioned control operations. In the figure, step 5T (1
) to determine whether there is a stop command for its own indoor unit 2, and if there is a stop command, step 5TI2
1, the operation of the indoor unit 2 is stopped. If there is no stop command, the process proceeds to step 5T(3), where it is determined whether another indoor unit 2 has been additionally activated or any indoor unit 2 has been stopped, that is, whether the signal 26 has been input.

If signal 26 is not input, return to step 5T (11); if signal 26 is input, return to step 5T (4)
Wait for time T to elapse, and during this time the pressure and temperature before the signal 26 was input are maintained. When the time T has elapsed, the process proceeds to step 5T (51), where the pressure and temperature are input again, and a predetermined calculation is performed based on this and the pressure and temperature held above to find the controlled variable ΔV.Next, Step 5T (
61, the opening degree of the electronic expansion valve 9 is controlled according to the above-mentioned ΔV, and then the process returns to step 5TIII.

In the above embodiment, the temperature detected by the temperature sensor 10 is converted to determine the outlet pressure of the electronic expansion valve 9, but it goes without saying that a pressure sensor may be used in place of the temperature sensor 10. be.

〔Effect of the invention〕

As described above, according to the present invention, the refrigerant flow rate is adjusted by controlling the opening of the electronic expansion valve based on the inlet side pressure and the outlet side temperature or pressure of the electronic expansion valve. The control response to changes in refrigerant flow rate is faster than before, so even if another indoor unit is additionally started or any indoor unit is stopped while the indoor unit is operating, the control response of the indoor unit that continues to operate is faster than before. This has the advantage that the operating state can be quickly restored to normal, and the behavior of the refrigerant in the entire refrigerant circuit system including the outdoor unit and the indoor unit can be quickly stabilized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a multi-room air conditioner according to an embodiment of the present invention, FIG. 2 is a block diagram showing a control device of the same device, and FIG. 3 is a flow chart showing the operation of the control device. FIG. 4 is a block diagram showing a conventional multi-room air conditioner, and FIG. 5 is a block diagram showing a control device for the same device. 1 is an outdoor unit, 2 is an indoor unit, 8 is a pressure sensor, 9 is an electronic expansion valve, 10 is a temperature sensor, and 15 is a control device. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. @ 1 Threshold IS Lord Breach 1 Figure 2 Figure 3 Figure 4 Prisoner @ Figure 5

Claims (1)

[Claims] In a multi-room air conditioner comprising a plurality of indoor units connected to one outdoor unit, a pressure sensor detects pressure on the input side of an electronic expansion valve in the indoor unit, and an output side of the electronic expansion valve. and a control device that controls the opening degree of the electronic expansion valve based on the detected pressure on the input side and the temperature or pressure on the output side. A multi-room air conditioner characterized by: