KR100565465B1 - Method to control oil balance and pressure of a air-conditioner's cooling ? heating apparatus - Google Patents

Abstract

The oil balance and pressure control method of the air conditioner according to the present invention includes at least two compressors having the same or different compression capacity, a condenser and an evaporator commonly connected to each compressor, an accumulator individually connected to each compressor, and a reverse flow of refrigerant. An air conditioner provided with a first pressure control means on the discharge side of each compressor to prevent oil, the air conditioner further comprising a connecting pipe for connecting the accumulators to recover oil, wherein the lower discharge side and each accumulator of the first pressure control means of each compressor are connected. By controlling the second pressure control means further included between the suction side, the pressure between the discharge pipe and the suction pipe is always equalized, and the pressure difference of the compressor which is stopped during the operation switching of the compressor is eliminated. It is characterized by making it possible.

Compressor, Evaporator, Condenser, Accumulator, Check Valve, Connecting Pipe, Solenoid Valve

Description

TECHNICAL TO CONTROL OIL BALANCE AND PRESSURE OF A AIR-CONDITIONER'S COOLING & HEATING APPARATUS}

1 is a schematic diagram of an air conditioner device having two compressors according to the prior art;

2 is a schematic diagram of an air conditioner device according to the present invention;

3 is a flowchart showing a method for controlling oil balance and pressure in an air conditioner according to the present invention.

 [Explanation of symbols on the main parts of the drawings]

4a, 4b: discharge tube 5: connector

6a, 6b: branch pipe 11a: first compressor

11b: second compressor 14a: first accumulator

14b: 2nd accumulator 20: connection piping

31a, 31b: solenoid valve 41a, 41b: check valve

50: condenser 61a, 61b: expansion device

71a, 71b: service valve 81a, 81b: evaporator

91: connector

The present invention relates to an air conditioner, and more particularly, to a pressure control method of an air conditioner device capable of eliminating oil balancing operation and operating standby time of an air conditioner device through at least two compressors and pressure control means.

Recently, the air conditioner is provided with a cooling device in which the cooling capacity is automatically controlled. The air conditioner described above is a simple control type using one constant speed compressor, a variable control type using a variable compressor, and a combined control type using two or more constant speed compressors.

As shown in FIG. 1, a conventional air conditioner including a hybrid controlled air conditioner includes a first compressor 100a and a second compressor 100b, an oil separator 600 commonly connected to each compressor, and a condenser connected to the oil separator. 300, an expansion device 500 connected to the condenser, an evaporator 200 connected to the expansion device, and a first accumulator 400a and a second accumulator 400b, which are commonly connected to the evaporator and individually connected to each compressor, respectively to each accumulator. The first capillary 700a and the second capillary 700b are connected to each other.

According to the conventional combined control type air conditioner described above, each compressor may be operated alone or simultaneously depending on load variation. Therefore, the conventional combined control type air conditioner can adjust the cooling capacity relatively efficiently.

However, in the conventional combined control air conditioner, when the compressor is controlled according to the load change, the compressor of the appropriate capacity must be operated again while the whole compressor is stopped, and the other stopped when one compressor is operated. The other compressor that is stopped due to the refrigerant pressure being applied to the discharge side of the compressor is not only impossible to operate, but also the refrigerant pressure is directly applied to the compressor being stopped, which may cause the failure of the compressor. In addition, in order to operate the stationary compressor, a predetermined time is required until the pressure between the discharge unit and the suction unit of the stationary compressor reaches an equilibrium.

In addition, due to the change in load and the compression capacity of the compressor, the reaching time of pressure equalization of the stopped compressor is different. Therefore, sufficient safety time should be considered when designing the actual device. Sometimes it stops.

Therefore, in the conventional combined control type air conditioner, the refrigerant discharged from the operating compressor is directly sucked into the discharge side of the compressor which is stopped, causing the failure of the compressor. If all must be started, a problem arises in that the compressor is stopped and restarted. At this time, the indoor temperature is increased, so that the user feels uncomfortable, and after the temperature rises, the operation is not economical because the power consumption is increased, and the energy efficiency obtained by varying the cooling capacity with a plurality of compressors cannot be obtained. .

Accordingly, the present invention is to solve the above problems of the prior art, improve the efficiency of the device by improving the structure of the air conditioner device having at least two compressors, and through the pressure balance control means such as solenoid valves of the compressor By controlling the pressure, the oil management and the compressor can be restarted or stopped smoothly to increase the energy efficiency and to keep the room comfortable.

In order to achieve the above object, the air conditioner according to the present invention is connected to the condenser and at least two compressors 11a and 11b having the same or different compression capacities and a condenser 50 connected to the discharge pipes of the respective compressors. At least two expansion devices (61a, 61b), at least two evaporators (81a, 81b) respectively connected to the expansion device, and each of the evaporators to recover oil discharged from the compressor, such as refrigerant, and to store excess refrigerant. Accumulators 14a and 14b respectively connected between the compressors and first compressors, first pressure control means respectively provided between the discharge pipe and the condenser of the compressors to prevent backflow of the refrigerant, the discharge side and the suction of the compressors. Second pressure control means respectively provided between the discharge pipe of each compressor and the suction side pipe of each accumulator so as to prevent pressure balance between the sides and reverse flow of oil; The controller (not shown) for controlling the air-conditioning device including a connecting pipe (20) provided between the accumulator is provided to the same to keep the oil level of each of the accumulators through the work flow.

Pressure control method of the air conditioning device according to the present invention in the controller

Detecting whether the operation command signal is a stop signal or an operation signal; in the case of a stop signal, turning off both compressors to maintain a stop standby state and closing all of the second pressure control means; Determining whether to operate the two compressors alone or simultaneously by sensing the set temperature and ambient air temperature of the compressor; and in the case of simultaneous operation, open all of the second pressure control means to balance the pressure. Closing all the control means; determining whether the operation is the initial operation or the continuous operation in the case of single operation; and in the case of the single operation and the initial operation, opening the second pressure control means to balance the pressure, and then (2) closing the pressure control means, and in stand-alone operation and continuous operation, to stop the pressure balance and oil backflow of the stopped compressor. Opening the second pressure control means of the compressor and normal operation of all of the selected compressors.

Referring to the drawings, the oil balance and the operating pressure control method of the air conditioner according to the present invention will be described.

First, if the air conditioner according to the present invention is described along with the flow of the refrigerant, the low-temperature low-pressure gas state refrigerant is compressed into a high-temperature high-pressure gas state refrigerant by at least two compressors (11a, 11b), the high-temperature high-pressure gas state The coolant is discharged through the discharge pipes 4a and 4b, and backflow of the coolant is prevented by the first pressure control means provided in the discharge pipe, and the high temperature and high pressure gaseous refrigerant passing through each discharge pipe is connected to the connection pipe. (5) flows into the condenser 50, the refrigerant introduced into the condenser is condensed and converted into a low-temperature high-pressure liquid state refrigerant, and is expanded in the expansion device (61a, 61b) to become a low-temperature low-pressure abnormal state refrigerant, Subsequently, it is transferred to the evaporators 81a and 81b to change into a gas state at low temperature and low pressure, and takes heat from the surroundings to cool the air around the evaporator. At this time, the refrigerant flows into or out of the evaporator connected through the service valves 71a and 71b and the connector 91. The refrigerant that cooled the ambient air in the evaporator is accumulator which is an oil separation and surplus refrigerant accumulating means through a connecting pipe 5 provided on one side of the evaporator and branch pipes 6a and 6b branched at the end of the connecting pipe 5. 14a, 14b), and the oil excessively introduced into one accumulator is distributed through the connecting pipe 20 connecting the accumulators to balance the oil, and an appropriate amount of oil and the recovered refrigerant are transferred to each accumulator. It is introduced into each connected compressor to form a cycle of recondensation.

At least two compressors described above are provided, and compressors having different compression capacities are preferably provided.

In addition, when the high-temperature, high-pressure refrigerant is discharged from each compressor (11a, 11b), the first pressure control means is provided to prevent the refrigerant from flowing into the compressor through the other compressor discharge pipe to reduce the failure and operation efficiency of the compressor Preferably, the flow of the refrigerant by the first pressure control means described above proceeds only in the discharge direction from the compressors 11a and 11b, and the first pressure control means includes check valves 41a and 41b. .

Further, a second pressure control means capable of eliminating the pressure difference between the discharge side and the suction side of each compressor to remove the operation waiting time is provided between the lower discharge side of the first pressure control means of each compressor and the suction side of each accumulator. .

The above-mentioned second pressure control means is composed of solenoid valves 31a and 31b. In particular, when the two compressors stop one of the compressors due to load change during simultaneous operation, the solenoid valve 31a is started again. By operating the pressure difference between the discharge side and the suction side of the stationary compressor, it is possible to prevent the oil of the stationary compressor from flowing back to the accumulator and to eliminate the pressure difference between the discharge side and the suction side. Can be removed.

Hereinafter, the oil balance and operating pressure control method of the air conditioner according to the present invention will be described in detail step by step.

First, in the step (S1) of detecting whether the operation command signal of the user is a stop signal or an operation signal in the controller (not shown) provided in the air conditioner device, the stop signal when the user's driving command signal is given according to indoor temperature or load. The controller selects the compressor by determining whether the two compressors are to be operated by the controller and whether to operate only one compressor alone or to simultaneously operate the two compressors.

Second, when the operation command signal is a stop signal, both compressors are turned off to close the second pressure control means of each compressor while maintaining the standby standby state. In step S2 of detecting the air temperature to determine whether only one of the two compressors is to be operated alone or to operate both compressors simultaneously, in the case of the stop signal, the second pressure of each compressor is maintained while the standby state is stopped. Close all control means to prevent waste of power consumption.In case of an operation signal, determine whether to operate only one compressor alone or two compressors according to the capacity of the compressor according to the set temperature of the indoor unit and the ambient air temperature. do.

Third, in the step (S3) of operating the two compressors from the beginning due to the large load, the compressors are opened by applying a power to the second pressure control means of each of the two compressors, and then operate each compressor with a predetermined time difference. After the operation, the power is removed from the second pressure control means and closed to operate each compressor normally. As a result, it is possible to prevent the operation current limiting effect and the operation failure due to the simultaneous operation generated by the pressure difference between the discharge side and the suction side.

Fourth, in case of single operation, whether the load is small and only one compressor is operated from the beginning (initial operation) or if one of the two compressors operated simultaneously due to load change is stopped and only one is operated (continuous operation). Determine (S4).

Fifth, in the case of the initial operation (S5) is a single operation and the load is small so that only one compressor is operated from the beginning (S5), first, power is applied to the second pressure control means of each of the two compressors to open them all. When the pressure between the discharge side and the suction side of each compressor is equalized, power is removed from the second pressure control means of the compressor to be operated to close it, and the compressor is normally operated. At this time, the refrigerant and oil discharged from the running compressor are blocked from entering the stationary compressor by the first pressure control means of the stationary compressor, and the stationary compressor is separated between the discharge side and the suction side by its second pressure control means. As the pressure is equalized, oil is prevented from flowing back from the stationary compressor to the accumulator and remains operational at any time.

Sixth, if one of the two compressors that are independently operated and operated simultaneously due to load fluctuations is stopped and in the case of continuous operation in which only one is operated (S6), it is stopped by applying power to the second pressure control means of the compressor being stopped and opening it. The pressure difference between the discharge side and the suction side of the compressor is eliminated and oil backflow is prevented. In detail

First, one of the compressors in operation is stopped, and the first pressure control means of the stopped compressor is closed to prevent backflow of the refrigerant. At this time, the suction side pressure of the compressor stopped by the running compressor is reduced, and since the discharge tube pressure of the stopped compressor is high pressure, the oil of the compressor being stopped is flowed back to the accumulator by the pressure difference between the discharge side and the suction side. This flows through the connecting pipe to the accumulator of the running compressor. This backflow of oil causes failure of the compressor at standstill.

In addition, when one of the two compressors operated simultaneously due to load fluctuations is stopped and only one is operated, and the stationary compressor must be restarted as the load increases, power is applied to the second pressure control means of the stationary compressor. Since it is in the maintained state, it is possible to start the compressor which is stopped immediately. After a predetermined time (for example, several seconds) after the operation, the power is removed and closed, and both compressors are normally operated. That is, the idle waiting time due to the pressure difference between the discharge side and the suction side of the stationary compressor is eliminated so that the stationary compressor can be immediately started as needed even when one compressor is in operation.

In the above, the technical idea of the operating pressure control method of the air conditioner apparatus having at least two compressors and the first and second pressure control means has been described together with the accompanying drawings, which illustratively describes the best embodiment of the present invention. The present invention is not limited thereto.

In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

 As described above, by controlling the first and second pressure control means provided in the air conditioner apparatus according to the present invention, when the compressor provided with at least two or more operating alone or at the same time the operation switching of the compressor is When required, power consumption reduction and energy efficiency can be obtained by preventing backflow of the refrigerant of each compressor and relieving the pressure difference between the discharge side and the suction side of each compressor to prevent oil backflow and to eliminate the standby time. In addition, it is possible to balance the oil discharged with the refrigerant from the compressor through the connection pipe, and can always maintain the comfort of the room.

Claims (5)

At least two compressors (11a, 11b) and a condenser (50) commonly connected to the discharge pipes of the respective compressors, at least two expansion devices (61a, 61b) connected to the condenser, and at least two connected to the expansion device, respectively. Evaporators 81a and 81b, accumulators 14a and 14b individually connected between each evaporator and each compressor to recover the oil discharged with the refrigerant in the respective compressors and to store the excess refrigerant; First pressure control means respectively provided between the discharge pipe and the condenser of the compressor, and the discharge pipe and each accumulator of the compressor to prevent the pressure balance between the discharge side and the suction side of the compressor and the reverse flow of oil. The accumulator to maintain the oil level of each accumulator through the flow of oil and the second pressure control means respectively provided between the suction side pipes of the A method of operation by a controller in the air-conditioning device including a connecting pipe (20) provided between,        Detecting whether the operation command signal is a stop signal or an operation signal; If it is a stop signal, turn off both compressors to maintain the stand-by state and close all of the second pressure control means.If the start signal detects the set temperature of the indoor unit and the ambient air temperature, Determining whether to operate simultaneously; In the case of simultaneous operation, opening all of the second pressure control means to balance the pressure, and then closing all of the second pressure control means; Determining whether the operation is the initial operation or the continuous operation in the case of single operation; Closing the second pressure control means of the selected compressor after all of the second pressure control means are opened to balance the pressure if the single operation and the initial operation are performed; Opening the second pressure control means of the stationary compressor to prevent pressure equalization and oil backflow of the stationary compressor if it is solely operated and in continuous operation; And A method of controlling oil balance and pressure in an air conditioner device comprising the step of operating all selected compressors. The method of claim 1, The compressor is the oil balance and pressure control method of the air conditioner, characterized in that the compression capacity is the same. The method of claim 1, The compressor has a different compression capacity of the oil balance and pressure control method of the air conditioner device. The method of claim 1, Oil balance and pressure control method of the air conditioning device, characterized in that the first pressure control means is composed of check valves (41a, 41b). The method of claim 1, The oil pressure and pressure control method of the air conditioner, characterized in that the second pressure control means is composed of a solenoid valve (31a, 31b).

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