JP2685474B2 - Multi-room air conditioner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat pump type multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit, and particularly to an operation during heating operation. The present invention relates to refrigerant control when the number of indoor units changes.

[Conventional technology]

A conventional device is a multi-room air conditioner as described in JP-A-61-114060, in which a liquid side main pipe of an outdoor unit is branched as a surplus refrigerant control means when an arbitrary indoor unit is stopped. A plurality of liquid side exchange pipes are each provided with an electric expansion valve, or a gas side main pipe of the outdoor unit is further provided with a solenoid valve, and an electric expansion valve corresponding to the stop indoor unit during cooling and heating, or By further controlling the opening and closing of the solenoid valve, the refrigerant distribution amount is controlled.

[Problems to be solved by the invention]

The above-mentioned conventional technology does not consider the optimal distribution of the refrigerant when the number of operating room units changes, and when the number of operating indoor units changes, the refrigeration cycle undergoes a large change. However, the above-mentioned conventional excess refrigerant control has a problem that it takes time to stabilize the refrigerant operation cycle.

The object of the present invention is to solve the above-mentioned problems, and even when the number of units in the operation room changes, while distributing the refrigerant to the operation room units without excess or deficiency, a proper amount of refrigerant is accumulated in the stop room unit as well. It is to obtain a comfortable air-conditioned space by quickly obtaining a stable air-conditioning cycle even with a large change in the refrigeration cycle, such as a change in the number of units in the driver's cab.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a single outdoor unit including a compressor, an outdoor heat exchanger, a four-way valve, etc., whose capacity can be controlled by an input frequency, and an indoor heat exchanger and the like through connection pipes. A plurality of indoor units, each of which is provided with an electric expansion valve in each of a plurality of liquid side branch pipes branching from the liquid side main pipe of the outdoor unit, and the refrigerant circulation amount of the operating indoor unit during heating operation is controlled by the electric expansion valve. In a heat pump type multi-chamber air conditioner whose opening and closing is controlled by, when the number of operating indoor units increases or decreases, the input frequency of the compressor is reduced to a predetermined value in advance and fixed at that frequency, and all indoor units are The corresponding electric expansion valve is set to a predetermined expansion valve opening preset according to the capacity of each indoor unit, and then the expansion valve corresponding to the indoor unit for which the operation command is issued. To return the body to the normal control, and the expansion valve corresponding to stop the indoor unit and the closed state, is intended to return the input frequency of the compressor to a predetermined value.

[Action]

When the number of cab units increases or decreases, the input frequency of the compressor is reduced in advance and fixed at that frequency.
The circulation amount of the refrigerant in the refrigeration cycle is fixed, and it can be prevented from largely fluctuating due to the disturbance of the refrigerant operation cycle.
That is, when the number of indoor units is large and the change in the number is large, the pressure change becomes large, but even at this time, it is possible to prevent a temporary pressure increase.

Also, since the electric expansion valve is set to a predetermined expansion valve opening degree according to the capacity of each indoor unit and the operation is performed for a predetermined time, the amount of refrigerant is the amount of refrigerant according to the capacity of each indoor unit and the heat load at that time. The refrigerant is properly distributed to each indoor unit without excess or deficiency until it is distributed to each indoor unit. That is, an appropriate amount of refrigerant is retained not only in the indoor unit that issued the operation command, but also in the stop unit.

After that, only the expansion valve corresponding to the indoor unit for which the operation command is issued is returned to the normal control, and the input frequency of the compressor is returned to a predetermined value, so that the number of operating indoor units changes quickly and Stable air conditioning can be performed.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, this air conditioner has a configuration in which three indoor units are connected to one outdoor unit, and the outdoor unit has a compressor 1, a four-way valve 2, whose capacity is variable according to an input frequency, Accumulator 3 and outdoor heat exchanger 4
And a receiver 5 provided on the refrigerant liquid side main pipe 6. Further, the three liquid side branch pipes 7a, 7b, 7c branched from the refrigerant liquid side main pipe 6 are respectively provided with forward and reverse flow electric expansion valves 8a, 8c.
Solenoid valves 11a, 11b and 11c are provided on b and 8c and refrigerant gas side branch pipes 10a, 10b and 10c, respectively, which branch the refrigerant gas side main pipe 9 into three. Then, the indoor unit side is provided with respective indoor heat exchangers 12a, 12b, 12c, and by connecting each device in the outdoor unit and each device in the indoor unit by piping as shown, a heat pump type refrigeration cycle Are configured. In addition, the outdoor unit is a terminal unit 13 to which a user's command such as a driving or stop command for each indoor unit is input.
Control device 14 that receives signals from a, 13b, 13c and determines the control content, compressor 1 and motor-operated expansion valves 8a, 8b, 8c and solenoid valves 11a, 11b, 11c are input to the compressor at the command of control device 14. frequency,
A control signal output device 15 for outputting the opening amount of the expansion valve and the opening / closing signal of the solenoid valve is provided.

FIG. 2 shows a control flow in this embodiment. The operation of the above configuration will be described.

When all the indoor units are operated during the heating operation, the refrigerant gas from the compressor 1 passes through the four-way valve 2, the gas-side main pipe 9, the gas-side branch pipes 10a to 10c, and the solenoid valves 11a to 11c, and the indoor heat exchanger. 12a to 12c to be condensed and electrically driven expansion valve 8a to
It is sent to the outdoor heat exchanger 4 via c, the liquid side branch pipes 7a to 7c, the liquid side main pipe 6, and the receiver 5, and evaporates into gas, which passes through the accumulator 3 and returns to the compressor 1. Here, when an operation stop command is issued from the terminal unit 13a to the indoor unit having the indoor heat exchanger 12a, the control device 14 detects a decrease in the number of operation rooms and first determines the input frequency of the compressor to a predetermined value. The control signal output device 15 is instructed to reduce the value. As a result, the control signal output device 15 reduces the input frequency of the compressor 1 to a predetermined value, reduces the compressor capacity, and fixes it at that frequency. In this way, the amount of refrigerant discharged from the compressor is reduced in advance and the amount of circulation is fixed, so that the refrigerant operation cycle is set so as not to largely fluctuate due to disturbance. Next, the control device 14 sets the electric expansion valves of all the indoor units to predetermined expansion valve openings preset according to the capacity of each indoor unit, and sets all the solenoid valves to the open state. The control signal output device 15 is commanded and executed. In this state,
After performing all room operation for a predetermined time, after distributing the refrigerant to the capacity of each indoor unit, an appropriate amount of refrigerant according to the heat load at that time,
The solenoid valves 11b and 11c corresponding to the indoor unit having the indoor heat exchangers 12b and 12c for which the operation command is issued are left in the open state,
The solenoid valve 11a corresponding to the stopped indoor unit is closed. Then, after a predetermined time, the expansion valve 8
The control of b and 8c is returned to under the PID control, and the expansion valve 8a corresponding to the stopped indoor unit is closed. At the same time, the compressor input frequency is returned to a preset predetermined value, and the refrigerant control when the number of units in the operating room changes is completed. The above control is summarized as shown in FIG.

By the above control, the refrigerant is distributed to the operation indoor unit without excess or deficiency, and an appropriate amount of refrigerant is accumulated in the stop indoor unit, so that it is possible to cope with a large change in the refrigeration cycle such as a change in the number of operation indoor units. A quick and stable air conditioning cycle can be obtained.

It should be noted that the present invention is not limited to the above-described embodiment, and, for example, a change in the number of units in the driving room is not limited to the operation stop or the operation start by the user, and the operation of the indoor unit in a state such as thermo-off is controlled. It may be stopped or restarted, and in the present invention, the reason for changing the number of cabs is considered to be moderate. Therefore, it can be moderately modified without changing the gist.

〔The invention's effect〕

According to the present invention, in the heating operation in the multi-room air conditioner, even when the number of units in the operation room changes, the refrigerant is distributed to the operation room units without excess or deficiency,
There is an effect that an appropriate amount of refrigerant is accumulated in the stopped indoor unit, and a quick and stable air conditioning cycle can be obtained even with a large change in the refrigeration cycle such as a change in the number of operating indoor units.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle system diagram showing an embodiment of a multi-room air conditioner of the present invention, and FIG. 2 is a control flow chart of the embodiment. 1 ... Compressor, 2 ... Four-way valve, 3 ... Accumulator,
4 ... Outdoor heat exchanger, 5 ... Receiver, 8a-c ... Electric expansion valve, 11a-c ... Solenoid valve, 14 ... Control device, 15 ...
... Control signal output device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Seki 390 Muramatsu, Shimizu City, Shizuoka Prefecture Inside the Shimizu Plant, Hiritsu Seisakusho Co., Ltd. (56) References JP-A-54-131335 (JP, A)

Claims (1)

(57) [Claims] 1. A compressor whose capacity can be controlled by an input frequency,
An outdoor heat exchanger, a single outdoor unit including a four-way valve, and a plurality of indoor units including an indoor heat exchanger and the like through connection pipes, respectively, and a plurality of branching liquid side main pipes of the outdoor unit. In the heat pump type multi-chamber air conditioner in which electric expansion valves are installed on the liquid side branch pipes, and the refrigerant circulation amount of the indoor units is controlled by the electric expansion valve during heating operation, the number of indoor units When the frequency is increased or decreased, the input frequency of the compressor is reduced to a predetermined value in advance and fixed at that frequency, and the electric expansion valves corresponding to all indoor units are preset according to the capacity of each indoor unit. After setting to a predetermined expansion valve opening, after that, only the expansion valve corresponding to the indoor unit for which the operation command is issued is returned to normal control, and the expansion corresponding to the stopped indoor unit is expanded. Was closed, the heat pump type multiple room air conditioning apparatus, characterized in that to return the input frequency of the compressor to a predetermined value.