JPH03211370A - Controller for expansion valve of multiple-air conditioner - Google Patents

Abstract

PURPOSE:To achieve a highly reliable operation of a compressor by a method wherein each of room units compares the received target lift of an electronic expansion valve with the lift of the expansion valve at present, and the electronic expansion valve is driven by the amount of deviation by electronic expansion valve driving circuits. CONSTITUTION:The target lifts of electronic expansion valves 14a and 14b on the room unit side are calculated by a valve lift arithmetic element for an electronic expansion valve 7 on outdoor unit 1 side considering the capacity codes of the indoor units 2A and 2B. This arithmetic is carried out, for example, based on the delivery temperature and the condensing temperature of refrigerant discharged from a compressor in the outdoor unit 1. The calculated target valve lift values are transmitted to the room units 2A and 2B through transmitting circuits 4 and 12A. On the room unit sides, the target valve lifts received are compared with the actual valve lifts at present, electronic expansion valves 14A and 14B are throttled or opened by the amounts equivalent to the deviations by electronic driving circuits 11A and 11B. Thereby, the refrigerating cycle is stabilized quickly and the reliability on the compressor is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a multi-room air conditioning system, that is, a multi-air conditioner, in which one outdoor unit and a plurality of indoor units are connected to form a refrigeration cycle. The present invention relates to an expansion valve control device.

[Prior Art] As is well known, an outdoor unit includes a compressor and an outdoor heat exchanger, that is, a heat source side heat exchanger, and an indoor unit includes an indoor heat exchanger, that is, a user side heat exchanger. A multi-air conditioner is constructed by connecting a plurality of indoor units to one outdoor unit as described above through a refrigerant circuit.

For example, Japanese Patent Publication No. 56-49856, Japanese Patent Application Publication No. 60-1
Publication No. 33274 and the like describe a multi-air conditioner, that is, a multi-room air-conditioning device.

In conventional multi-air conditioners, a solenoid valve installed in the expansion mechanism (capillary) of the indoor unit performs on/off control based on the deviation between the room temperature and the set temperature, and the opening degree of the expansion valve is not controlled.

[Problems to be solved by the invention] In the above conventional multi-air conditioners, fluctuations in the refrigeration cycle are not taken into account, so the refrigeration cycle is unstable, the reliability of the compressor cannot be maintained, and stable air conditioning is not possible. I couldn't do it. There is also the problem that standardization for control on the indoor unit side is not possible. In other words, in order to solve the drawbacks of the conventional device as described above, even if the opening control is improved from the on/off control of the solenoid valve to the opening of the expansion valve and the opening value is calculated as required, the indoor The software is different for different unit capacities, making it impossible to standardize and not applicable to different refrigeration cycles.

Therefore, the present invention provides a multi-air conditioner expansion valve control device that can provide a stable refrigeration cycle, operate a compressor with high reliability, and can be standardized and applied to different indoor units. It is intended to.

[Means for Solving the Problems] A control device for an expansion valve of a multi-air conditioner according to the present invention has the features described in each claim.

[Function] The opening degree of the electronic expansion valve of the indoor unit is controlled as follows. That is, the electronic expansion valve opening calculation section on the outdoor unit side calculates the target opening value of the electronic expansion valve of each indoor unit in consideration of each indoor unit capacity code. This calculation is performed based on, for example, the discharge gas temperature from the compressor of the outdoor unit and the condensation temperature. The calculated target opening values are then transmitted to each indoor unit via the transmission circuit. On each indoor unit side, the received target opening value of the electronic expansion valve is compared with the current opening value, and the electronic expansion valve is closed or opened by the deviation. controlled.

[Example] As an example of the present invention, an example in which an electronic expansion valve is also provided on the outdoor unit side will be described below. In this embodiment, as shown in FIG. 1, the refrigeration cycle of the multi-air conditioner consists of one outdoor unit 1 and two indoor units 2A and 2B. FIG. 1 shows the state during cooling. The outdoor unit 1 includes a compressor 20, a heat source side heat exchanger 21, an electronic expansion valve 7° accumulator 22, and a four-way switching valve 3. The discharge pipe of the compressor 20 contains high pressure gas (discharge gas).
A pressure sensor 10 that detects pressure values and a temperature sensor 9 that detects high pressure gas temperature are provided.

The indoor units 2A, 2B are user-side heat exchangers 23A, 2
3B, and electronic expansion valves 14A and 14B, respectively. These units 1.2A and 2B are connected through a refrigerant circuit to form a refrigeration cycle.

The circuit for controlling the above refrigeration cycle.

It is shown in Figure 2. On the outdoor unit 1 side, there is a transmission circuit 4 for transmitting and receiving data between each indoor unit 2A and 2B. A memory 6 that stores the electronic expansion valve target opening calculated using the signals from the sensors 9 and 10, an electronic expansion valve target opening 8 that drives the electronic expansion valve 7, and an electronic expansion valve 14A of each indoor unit. Memories 16A and 16B are provided to store the target opening value of 14B. In addition, on the indoor unit side, transmission circuits 12A and 12B for transmitting and receiving data with the outdoor unit, indoor unit capacity code setters 15A and 15B, and electronic expansion valves 14A and 14B are provided.
Memories 13A, 13B for storing the current opening degree of the electronic expansion valves 14A, 14B, and an electronic expansion valve immediate action circuit 11A for driving the electronic expansion valves 14A, 14B.

11B is provided.

Next, the operation of the above embodiment will be explained.

When the power is turned on, the electronic expansion valve 7 of the outdoor unit 1 and the electronic expansion valves 14A and 14B of the indoor units 2A and 2B are activated.
are the respective electronic expansion valve drive circuits 8, 11. −． 11
It is initialized by B and set to the initial opening degree.

Also indoor unit 2A.

2 Indoor unit capacity code setting device 15A on B side
, 15B to the transmission circuit 4 of the outdoor unit 1 via transmission circuits 12A and 12B.
Send to.

After the refrigeration cycle starts operating and enters steady operation, the outdoor unit calculates the condensation temperature from the high pressure gas pressure value input from the pressure sensor 9, and calculates the condensation temperature of the high pressure gas input from the temperature sensor 9. Based on the temperature and the above condensation temperature, the electronic expansion valve l] target opening degree is calculated, and this is stored in the memory 6.
write to. This electronic expansion valve target opening degree means the overall electronic expansion valve opening degree corresponding to the optimum refrigerant flow rate for the entire refrigeration cycle.

During cooling operation, on the outdoor unit side, the electronic expansion valve drive circuit 8 operates so that the electronic expansion valve 7 is kept at an appropriate constant opening degree (actually, fully open), and on the other hand, the above calculation stored in the memory 6 is performed. The electronic expansion valve target opening value is distributed according to the ratio of the indoor unit capacity codes transmitted from the indoor units 2A and 2B, and the distributed opening value is
4A.

Each memory 16 is used as the target opening value data of 14B.
A, store in 16B. From the transmission circuit 4 of the outdoor unit, the transmission circuits 12Δ and 12B of the indoor units 2A and 2B are connected.
The target opening values of the electronic expansion valves 14A and 14B are transmitted from the memories 16A and 16B. On each indoor unit side, the received target opening values and the memory 13A
, 13B, and the electronic expansion valve 14A is moved by the difference, for example, if the difference is positive, the electronic expansion valve 14A is moved in the opening direction, and if the difference is negative, the electronic expansion valve 14A is moved in the closing direction.

14B are driven by drive circuits 11A and IIB, respectively. The respective target opening values newly received from the outdoor unit are stored in the memories 13A and 13B.

In the heating operation H5, the four-way switching valve 3 is switched from the state shown in FIG. 1 to reverse the flow direction of the refrigerant. In the case of heating operation, the electronic expansion valve 7 is driven by the difference between the calculated electronic expansion valve L] standard opening value stored in the memory 6 and the current opening of the expansion valve 7. It is driven by circuit 8. On the other hand, a memory 16A for the electronic expansion valve opening of the indoor unit.

16B each stores a constant target opening value (actually, fully open). The data on the memories 16A, 16B is transmitted to the indoor units 1 through the transmission circuit 4 to the electronic expansion valve 14A, as in the case of cooling operation.

1, 4. B are driven by drive circuits 11A and 11B so as to maintain the above-mentioned constant target opening degrees.

Although not shown, in the outdoor unit are the electronic expansion valve target opening degree to be stored in the memory 6 in each case of cooling operation and heating operation, and each indoor unit electronic expansion valve 14A to be stored in the memories L6A and 16B. 14B is provided with an electronic expansion valve opening calculating section that calculates and determines each target opening.

If electronic expansion valves are provided in both the outdoor unit and the indoor unit as in this embodiment, they can be used depending on the air conditioning and heating, and the refrigeration cycle has the effect of making the refrigeration cycle more stable.

FIG. 3 shows an electronic expansion valve opening correction switch 16A-1,
16A-2 is shown. If the correction switches 16A-1 and 16A-2 are both off, no correction will be made, but if the switch 16A-1 is on and the switch 16A-2 is off, the electronic expansion valve opening sent from the memories 16A and 16B of the outdoor unit, for example. The degree data is increased by 5%, when switch 16A-1 is off and switch 16A-2 is on, it is increased by 10%, and when both switches 16A-1 and 16A-2 are on, the data is increased by 15%. . This corrected data is compared with the data on the memories 13A, 13B, and the opening degrees of the electronic expansion valves 14A, 14B are controlled as described above.

In this way, if a correction switch is provided, there will be a difference in the piping length of each indoor unit to the outdoor unit,
Even if there is a difference in resistance of the refrigerant depending on the pipe.

Odors can be corrected, and refrigerant distribution can be controlled appropriately throughout the entire refrigeration cycle of a multi-air conditioner.

[Effects of the Invention] As detailed above, according to the present invention, the opening degree of the electronic expansion valve on the indoor unit side can be determined on the outdoor unit side, and the refrigeration cycle can be adjusted depending on the capacity of the indoor units, the number of connected indoor units, etc. The indoor unit's electronic expansion valve can be precisely controlled in response to changes in temperature, resulting in faster stabilization of the refrigeration cycle.

The reliability of the compressor can be maintained. Furthermore, since the indoor unit is controlled by the outdoor unit, the control of the indoor unit can be standardized, and there is an effect that it can be used with air conditioners with different refrigeration cycles.

[Brief explanation of drawings]

Fig. 1 is a refrigeration cycle diagram showing one embodiment of the present invention;
FIG. 3 is a block diagram showing a control device, and FIG. 3 is a control block diagram similar to FIG. 2 including a correction switch. 1 Outdoor units 2A, 2B/indoor units 8, ], LA, IIB...electronic expansion valve drive circuit 7.1
4A, 14B Electronic expansion valve 4.12A/Transmission circuit 13A, 13B...Memory 21...Heat source side heat exchanger 23A, 23B/User side heat exchanger (1 other person)

Claims (1)

[Scope of Claims] 1 Consists of one outdoor unit having a compressor and a heat source side heat exchanger, and a plurality of indoor units each having a user side heat exchanger and an electronic expansion valve, and these units in a multi-air conditioner connected to form a refrigeration cycle, the outdoor unit includes an electronic expansion valve opening calculation section, and each of the indoor units includes an electronic expansion valve drive circuit that controls the opening of each electronic expansion valve. and a respective indoor unit capacity code setting section, and each indoor unit transmits the indoor unit capacity code set in the indoor unit capacity code setting section to the outdoor unit via the transmission circuit, and the electronic expansion valve of the outdoor unit. The opening degree calculation section calculates the electronic expansion valve target opening value for each indoor unit by taking into account the received indoor unit capacity code, and transmits it to each indoor unit via the transmission circuit, and each indoor unit receives the electronic expansion valve target opening value for each indoor unit. The target opening value of each electronic expansion valve is compared with the current opening of each electronic expansion valve, and the electronic expansion valve drive circuit drives each electronic expansion valve by the difference. A control device for the expansion valve of a multi-air conditioner. 2. The indoor unit is provided with an electronic expansion valve opening correction switch, and depending on the open/closed state of the switch, the electronic expansion valve target opening value transmitted from the electronic expansion valve opening calculation section of the outdoor unit is adjusted at a fixed rate. 2. The control device for an expansion valve of a multi-air conditioner according to claim 1, wherein the control device is adapted to perform correction.