JP2023157567A - air conditioner - Google Patents

Abstract

To provide an air conditioner that can control the inflow of a liquid refrigerant at the start of operation without requiring a large accumulator.SOLUTION: An air conditioner 100 comprises: one indoor unit 7 comprising a compressor 1, an indoor heat exchanger 5, an expansion valve 4, and an accumulator 16; and first and second outdoor units A6 and B6 comprising a first outdoor heat exchanger A2, and connected to the indoor unit 7 by refrigerant pipes. The air conditioner 100 comprises a valve control part for controlling the delay opening operation of first and second solenoid valves A1 and B1 provided in first and second lead-out refrigerant pipes L2a1 and L2b1 for sending a refrigerant to the indoor unit 7 from the first and second outdoor units A6 and B6, respectively.SELECTED DRAWING: Figure 1

Description

The present invention relates to an air conditioner including two or more outdoor units for one indoor unit, and for example, to an air conditioner suitable for air conditioning in a room in which information communication equipment is installed.

During cooling/heating operation of an air conditioner whose indoor unit is equipped with a compressor, evaporator, accumulator, expansion valve, and blower, and whose outdoor unit is equipped with a condenser and liquid refrigerant storage tank, when the outside air is cold and the air conditioner is started, Liquid refrigerant returns to the indoor unit. This returned liquid refrigerant is stored in an accumulator, but by enlarging this accumulator, return of the liquid refrigerant to the compressor is avoided. Furthermore, in Patent Document 1, for the purpose of protecting the compressor from liquid back and making the outdoor unit smaller and more compact by downsizing or eliminating the accumulator, a refrigerant circuit switching valve is used to switch the refrigeration cycle into a heating cycle when starting the air conditioner, and , discloses refrigerant expulsion control in which the indoor electric expansion valve is opened, the indoor fan is started in a stopped state, and when specified conditions are met, the refrigeration cycle is switched to the cooling cycle and cooling operation is started. .

Japanese Patent Application Publication No. 2009-144940

When the outside air becomes cold, refrigerant accumulates in the outdoor unit while it is stopped, and at the same time as operation starts, the liquid refrigerant accumulated in the outdoor unit flows into the indoor unit, increasing the amount of liquid refrigerant in the accumulator, and when the accumulator is filled with liquid. The compressor sucks in liquid refrigerant, causing liquid compression and risk of compressor failure. Conventionally, suction of liquid refrigerant into the compressor was avoided by increasing the capacity of the accumulator, but in large-capacity air conditioners where two or more outdoor units are connected to one indoor unit, A large accumulator is required, leading to an increase in the size of the indoor unit, an increase in the production cost of the accumulator, and an increase in the mass of the indoor unit.

Therefore, an object of the present invention is to provide an air conditioner that can control the flow of liquid refrigerant at the start of operation without requiring a large-sized accumulator.

The present invention provides one indoor unit having a compressor, an indoor heat exchanger, an expansion valve, and an accumulator, and at least two units having an outdoor heat exchanger and connected to the one indoor unit by refrigerant piping. An air conditioner comprising the above-mentioned outdoor units, a valve provided in each of the refrigerant lead-out pipes for sending refrigerant from the two or more outdoor units to the indoor unit, and a valve provided in each of the lead-out refrigerant pipes. and a valve control section that controls the delayed opening operation of the valve.

According to the present invention, by providing a delay in the opening operation of the valve provided in the outdoor unit at the start of operation, excessive flow of liquid refrigerant into the indoor unit can be avoided, and the accumulator provided in the indoor unit and the size of the indoor unit can be reduced. It is possible to aim for

FIG. 1 is an overall configuration diagram schematically showing an air conditioner according to an embodiment. It is a flowchart which shows the opening operation procedure of the valve of an air conditioner. It is a flowchart which shows the closing operation procedure of the valve of an air conditioner.

The main device configuration in the present invention will be explained. Additional equipment may be provided in the indoor or outdoor unit.

FIG. 1 is a diagram showing the configuration of an air conditioner 100. The indoor unit 7 constituting the air conditioner 100 is installed, for example, in a room where information and communication equipment (such as a server) is installed (a room with little load fluctuation and a somewhat constant temperature throughout the year, such as a server room). will be installed. The air conditioner 100 is constantly in a cooling operation, thereby cooling information and communication equipment that generates heat.

The air conditioner 100 includes, for example, an indoor unit 7 installed in a server room, and a first outdoor unit A6 and a second outdoor unit B6 installed outdoors. Furthermore, the air conditioner 100 uses refrigerant piping. The indoor unit 7 includes a compressor 1 , an indoor heat exchanger 5 (evaporator), an indoor fan 18 , an expansion valve 4 , and an accumulator 16 . The indoor unit 7 includes a check valve 22 that is used when a refrigeration cycle using the compressor 1 is used.

The first outdoor unit A6 includes a first outdoor heat exchanger A2 (condenser), a first surplus refrigerant adjustment device A9 (receiver tank), a first outdoor fan A8, and a first solenoid valve A1. There is. The second outdoor unit B6 includes a second outdoor heat exchanger B2 (condenser), a second surplus refrigerant adjustment device B9 (receiver tank), a second outdoor fan B8, and a second solenoid valve B1. There is.

The first outdoor unit A6 and the second outdoor unit B6 are connected to the indoor unit 7 through respective refrigerant pipes (L1, L2, L1a1, L2a1, L1b1, L2b1). The compressor, expansion valve 4, and indoor heat exchanger 5 housed in the indoor unit 7, and the outdoor heat exchanger A2 housed in the first outdoor unit A6 are connected to the refrigerant pipes (L1, L2, L1a1, L2a1). The outdoor heat exchanger B2 housed in the second outdoor unit B6 is connected to the refrigerant pipes (L1, L2, L1b1, L2b1). This forms a refrigeration cycle in which the outdoor heat exchangers A2 and B2 are arranged in parallel. The outlet refrigerant pipe L1 on the indoor unit 7 side is branched into the first and second introduction refrigerant pipes L1a1 and L1b1 on the first and second outdoor units A6 and B6 sides, and the refrigerant pipe L1 on the first and second outdoor units A6 and B6 sides The first and second outlet refrigerant pipes L2a1 and L2b1 are joined to the introduction refrigerant pipe L2 on the indoor unit 7 side.

In the air conditioner 100, a refrigerant cycle is formed by flowing the refrigerant through the compressor 1, the first and second outdoor heat exchangers A2 and B2, the expansion valve 4, and the indoor heat exchanger 5 in this order. There is. Then, the gas refrigerant discharged from the compressor 1 of the indoor unit 7 is supplied to the first outdoor heat exchanger A2 of the first outdoor unit A6 via the first introduction refrigerant pipe L1a1 branched from the outlet refrigerant pipe L1. be done. The gas refrigerant is condensed by outside air in the first outdoor heat exchanger A2, becomes a liquid refrigerant, and is supplied to the first surplus refrigerant adjustment device A9. The liquid refrigerant of the first surplus refrigerant adjustment device A9 flows from the first outlet refrigerant pipe L2a1 through the introduction refrigerant pipe L2 of the indoor unit 7, expands in the expansion valve 4, becomes a low-temperature and low-pressure liquid refrigerant, and is transferred to the indoor heat exchanger. 5. In the indoor heat exchanger 5, the refrigerant evaporates to become a gas refrigerant, and the cold heat is released into the room, thereby cooling the room. Then, the gas refrigerant discharged from the indoor heat exchanger 5 is returned to the compressor 1 via the accumulator 16. The flow of refrigerant in the second outdoor unit B6 is similar to the flow of refrigerant in the first outdoor unit A6.

The indoor unit 7, the first outdoor unit A6, and the second outdoor unit B6 are connected to a communication cable or the like to communicate with each other. The indoor unit 7, the first outdoor unit A6, and the second outdoor unit B6 are not limited to being connected by a communication cable or the like, but can also communicate wirelessly using Wi-Fi (registered trademark) or the like. It may be configured to do so.

A facility manager operates the indoor unit 7 using a controller placed indoors. The administrator operates the controller and sends commands such as starting and stopping the indoor unit 7, changing the set temperature, etc. to the indoor unit 7. Opening/closing control of the first and second solenoid valves A1 and B1 is performed by the control board 50 via first and second interfaces (I/F) A52 and B52 connected via electric signal lines (not shown). be exposed. In this embodiment, the control board 50 has the function of a valve control section that controls the delayed opening operation of the valve. A temperature sensor is provided in at least one of the first and second outdoor units A6 and B6. Information on the outside temperature measured by the temperature sensor is transmitted to the control board 50 via first and second interfaces (I/F) A52 and B52.

Next, the operation flow of the first and second electromagnetic valves A1 and B1 by the valve control unit when the air conditioner 100 starts operating will be described with reference to FIG. 2A. First, the air conditioner 100 is stopped, and the first and second solenoid valves A1 and B1 are all closed.

In step S1, the air conditioner 100 receives an operation command and starts operating. As a result, the compressor 1 is started.

In step S2, after the compressor 1 is started, the first solenoid valve A1 of the first outdoor unit A6 is opened. The valve control unit sends a first valve opening command to open the first solenoid valve A1 to the first solenoid valve A1. The first solenoid valve A1 opens the solenoid valve in response to this first valve opening command. The solenoid valve opens and liquid refrigerant is sent from the first outdoor unit A6 to the indoor unit 7. On the other hand, since the second solenoid valve B1 of the second outdoor unit B6 remains closed, liquid refrigerant is not sent to the indoor unit 7 from the second outdoor unit B1.

In step S3, the second solenoid valve B1 of the second outdoor unit B6 is opened after operation for a certain period of time at a predetermined outside temperature or higher or lower than a predetermined outside temperature. The valve control unit sends a second valve opening command to open the second solenoid valve B1 to the second solenoid valve B1. The second solenoid valve B1 opens the solenoid valve in response to this second valve opening command. The solenoid valve opens and liquid refrigerant is sent from the second outdoor unit B6 to the indoor unit 7. The "predetermined outside temperature" is preset to, for example, 6° C., 4° C., 2° C., 0° C., etc., depending on the installation environment and the equipment specifications of the air conditioner. The "certain period of time" is, for example, a set value determined from the liquid refrigerant storage capacity of the accumulator 16, a set value determined from a physical simulation, a set value determined from experimental values, a set value determined from real-time liquid level data of the accumulator 16. It may be a value.

Next, the operation flow of the first and second solenoid valves A1 and B1 when the operation of the air conditioner 100 is stopped will be described with reference to FIG. 2B.

In step S11, the air conditioner 100 receives a stop command and stops. As a result, the compressor 1 is stopped. In step S12, after the compressor 1 is stopped, the first solenoid valve A1 and the second solenoid valve B6 of the first outdoor unit A6 are closed. The valve control unit sends a first valve close command to close the first solenoid valve A1 to the first solenoid valve A1. The first solenoid valve A1 closes the solenoid valve in response to this first valve closing command. The valve control unit also sends a second valve close command to close the second solenoid valve B1 to the second solenoid valve B1. The second solenoid valve B1 closes the solenoid valve in response to this second valve closing command.

According to the above embodiment, at the start of operation, by opening the first solenoid valve A1 and then opening the second solenoid valve B1 with a delay, excessive liquid is released from the first and second outdoor units A6 and B6 to the indoor unit. The flow of refrigerant can be avoided.

(Another embodiment)
(1) Although the air conditioner 100 of the above embodiment includes two outdoor units, the number is not limited to two and may include three or more. Each of the three or more outdoor units is provided with a valve, and the opening operation of the valve is controlled to delay. As a delay control, the valves may be opened sequentially one by one with a delay such that the first valve opens, then the second valve opens, and then the third valve opens, or The third valve opens, and then the valves of the remaining outdoor units may open at the same timing, or the valves of all the remaining outdoor units may open at the same timing.
(2) The indoor unit 7 of the above embodiment is equipped with a temperature sensor that measures the refrigerant temperature on the outlet side of the indoor heat exchanger 5 and a temperature sensor that measures the refrigerant temperature on the outlet side of the accumulator 16 when the refrigeration cycle is used. Good too.
(3) The indoor unit 7 of the above embodiment may include a pressure sensor that measures the refrigerant pressure on the discharge side of the compressor 1 when the refrigeration cycle is used.
(4) The accumulator 16 of the above embodiment may be provided with a liquid level sensor that detects the height of the liquid refrigerant accumulated inside.
(5) In the above embodiment, the present invention is not limited to the first and second electromagnetic valves A1 and B1, and other valve mechanisms, expansion valves, gate valves, etc. may be used.
(6) Delay control of valve opening operation also includes control to slow down the speed at which the valve opens. In this case, in steps S2 and S3, the valve control section may adjust the speed at which the valve opens depending on the outside temperature.
(7) The air conditioner 100 may have one outdoor unit. In this case, each component of the first outdoor unit A6 and the second outdoor unit B6 in FIG. 1 is provided in the casing of one outdoor unit. That is, since a plurality of heat exchangers are provided in one housing, a plurality of parallel refrigeration cycles are formed in one indoor unit.

(Air conditioner control method)
A method for controlling an air conditioner includes one indoor unit having a compressor, an indoor heat exchanger, an expansion valve, and an accumulator, and an outdoor heat exchanger, which is connected to the one indoor unit through refrigerant piping. A method for controlling an air conditioner comprising at least two or more outdoor units, the method comprising:
The method includes a valve provided in each of the refrigerant outlet pipes that send refrigerant from the two or more outdoor units to the indoor unit, and a valve control step that controls a delayed opening operation of the valve provided in each of the refrigerant outlet pipes.
In the valve control step, after the compressor is started, the first valve is opened, and after operating for a certain period of time at a temperature above a predetermined outside temperature or below a predetermined outside temperature, the other valves (or valves may be plural) are opened sequentially or the remaining valves are opened. Control may be performed to open all valves at the same timing.

1 Compressor 4 Expansion valve 5 Indoor heat exchanger 7 Indoor unit 8 Outdoor heat exchanger 16 Accumulator 50 Control board (valve control section)
100 Air conditioner A1 First solenoid valve A2 First outdoor heat exchanger A9 First surplus refrigerant adjustment device A6 First outdoor unit B1 Second solenoid valve B2 Second outdoor heat exchanger B9 Second surplus refrigerant adjustment device B6 Second outdoor unit

Claims (5)

One indoor unit having a compressor, an indoor heat exchanger, an expansion valve, and an accumulator, and at least two or more outdoor units having an outdoor heat exchanger and connected to the one indoor unit by refrigerant piping. an air conditioner comprising: a valve provided in each of the refrigerant extraction pipes for sending refrigerant from the two or more outdoor units to the indoor unit; and a delayed opening operation of the valve provided in each of the refrigerant extraction pipes. a valve control unit that controls the
Air conditioner. One indoor unit having a compressor, an indoor heat exchanger, an expansion valve, and an accumulator, and an outdoor unit having two or more outdoor heat exchangers and connected to the one indoor unit by refrigerant piping. An air conditioner comprising: a valve provided in each of the refrigerant extraction piping for sending refrigerant from the two or more outdoor heat exchangers to the indoor unit; and a delayed opening of the valve provided in each of the extraction refrigerant piping. a valve control unit that controls the operation;
Air conditioner. The valve control unit controls opening of valves provided in each of the refrigerant pipes after starting the compressor.
The air conditioner according to claim 1 or 2. The valve control unit controls a delayed opening operation after operating for a certain period of time at a predetermined outside temperature or higher or lower than a predetermined outside temperature.
The air conditioner according to claim 1 or 2. The valve control unit performs control to adjust the speed at which the valve opens depending on the outside temperature.
The air conditioner according to claim 1 or 2.