Variable-frequency low-temperature air conditioning unit

Abstract

The utility model relates to the technical field of air conditioners, in particular to a variable-frequency low-temperature air conditioning unit which comprises a compressor, a condenser, a one-way valve, a liquid storage tank, an electromagnetic valve, a throttling element and an evaporator which are sequentially connected, a pressure sensor is connected to an exhaust port of the compressor, and a refrigerant outlet of the condenser is connected to a liquid inlet of the liquid storage tank through the one-way valve. And a liquid outlet of the liquid storage tank is connected to the throttling element through an electromagnetic valve. Low-temperature normal starting of the air conditioning unit can be achieved according to the environment temperature and refrigeration requirements, and the problem that the air conditioning unit fails to start in the outdoor low-temperature environment is solved.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning technology, and in particular to a variable frequency low temperature air conditioning unit. Background Technology

[0002] The application range of outdoor ambient temperature for data center air conditioning is becoming increasingly wide, especially in northern regions where outdoor ambient temperatures often reach -40℃, requiring the air conditioning system to be activated to cool the heat load inside the data center. The lower the outdoor ambient temperature, the more unfavorable it is for the start-up of the data center air conditioning system. This is because during the startup process, the low outdoor temperature makes it difficult to establish high pressure, leading to difficulties in liquid return to the unit, low-pressure air suction, and ultimately, unit startup failure. Utility Model Content

[0003] Based on the above problems, the purpose of this utility model is to provide a variable frequency low-temperature air conditioning unit that can start normally at low temperatures according to the ambient temperature and cooling demand, thus solving the problem of air conditioning unit failure to start in low outdoor environments.

[0004] The technical solution adopted in this utility model is a variable frequency low-temperature air conditioning unit, comprising:

[0005] The compressor, condenser, check valve, liquid receiver, solenoid valve, throttling element, and evaporator are connected in sequence.

[0006] A pressure sensor is connected to the compressor exhaust port, the refrigerant outlet of the condenser is connected to the liquid inlet of the liquid receiver via a one-way valve, and the liquid outlet of the liquid receiver is connected to the throttling element via a solenoid valve.

[0007] Compressors, condensers, throttling elements, and evaporators are conventional components of air conditioning units. This utility model uses a low-temperature device composed of a one-way valve, a liquid receiver, and a solenoid valve to achieve low-temperature start-up.

[0008] In practice, an outdoor fan is installed next to the condenser, and an indoor fan is installed next to the evaporator.

[0009] The compressor compresses a low-temperature, low-pressure gaseous refrigerant to form a high-temperature, high-pressure gaseous refrigerant. A pressure sensor detects the high-pressure at the compressor's exhaust port, which is used to determine whether the air conditioning unit needs to execute a low-temperature start-up logic. The condenser primarily uses an outdoor cold source to cool and condense the high-temperature, high-pressure refrigerant into a room-temperature, high-pressure liquid refrigerant. The outdoor fan primarily uses circulating airflow to exchange heat and remove heat from the condenser. A one-way valve ensures that the refrigerant entering the receiver tank does not flow backwards. The receiver tank stores the liquid refrigerant condensed by the condenser. A solenoid valve prevents the liquid refrigerant in the receiver tank from migrating to the evaporator when the unit is stopped. The throttling element primarily throttles, cools, and depressurizes the room-temperature, high-pressure liquid refrigerant in the receiver tank into a low-temperature, low-pressure gas-liquid mixture for refrigerant. The solenoid valve and throttling element work together to control the opening and closing of the path from the receiver tank to the evaporator under different start-up logics. The evaporator primarily uses an indoor heat source to evaporate the low-temperature, low-pressure gas-liquid mixture into a low-temperature, low-pressure gaseous refrigerant. The indoor fan primarily uses circulating airflow to exchange heat and remove heat from the evaporator.

[0010] In practice, liquid storage tanks of different volumes and forms can be customized according to the unit size and cooling capacity range. They can be used for in-row air conditioners, room-level air conditioners, or rack-mounted air conditioners. The liquid storage tank can be placed in the indoor unit or the outdoor unit.

[0011] Furthermore, the throttling element is an electronic expansion valve.

[0012] Furthermore, it also includes: a selection unit, whose control terminal is connected to a pressure sensor, whose first output terminal is connected to a normal start control module, and whose second output terminal is connected to a low temperature start module; wherein the normal start control module is a module that uses existing technology to control the normal operation of the air conditioning unit;

[0013] The low-temperature start-up module includes a timing control unit. The output of the timing control unit is connected to the control terminal of the solenoid valve and the control terminal of the electronic expansion valve. The control terminal of the timing control unit is connected to the second output terminal of the selection unit and the status feedback terminal of the compressor.

[0014] The operating principle of this utility model is as follows:

[0015] The unit starts according to cooling demand, the indoor fan runs, and the selection unit determines whether the outdoor temperature is low by measuring the high pressure through the pressure sensor. If the outdoor temperature is low, the low temperature start logic is executed in sequence: the selection unit controls the solenoid valve and the throttling element (electronic expansion valve) to open in advance through the timing control unit of the low temperature start module, releasing some refrigerant from the liquid receiver into the evaporator. At the same time, the one-way valve in front of the liquid receiver inlet prevents the refrigerant in the liquid receiver from migrating to the outdoor condenser. The indoor fan continues to exchange heat to ensure that the refrigerant in the evaporator is gaseous. The timing control unit starts timing and controls the solenoid valve to close after a certain time to avoid liquid slugging of the compressor due to prolonged refrigerant release. The compressor starts running, and its speed data is fed back to the timing control unit through the status feedback terminal. After the compressor reaches a certain speed, the timing control unit controls the solenoid valve to reopen. Since the liquid receiver continues to supply refrigerant, the compressor will not suck in cavitation. The compressor continuously increases its frequency, slowly builds up high pressure, and finally completes the start-up.

[0016] If the selection unit determines that the outdoor temperature is not low based on the high pressure measured by the pressure sensor, it will execute the normal startup logic sequence, that is, the selection unit will start the air conditioning unit according to the normal startup control module and the conventional logic.

[0017] The beneficial effects of this utility model are as follows:

[0018] When the outdoor ambient temperature is relatively low and there is a cooling demand in the computer room, the air conditioning unit needs to start and operate at a low temperature. This utility model, through targeted air conditioning unit system design, adds a liquid storage tank, a one-way valve and a solenoid valve to the traditional air conditioning unit structure, which can realize the normal start-up of the air conditioning unit at low temperatures according to the ambient temperature and cooling demand, thereby ensuring the application of the air conditioning unit in low-temperature environments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the air conditioning unit structure according to an embodiment of the present utility model;

[0020] Figure 2 This is a schematic diagram of the electrical connection of the air conditioning unit according to an embodiment of the present utility model. Detailed Implementation

[0021] To better understand the above-mentioned objectives, features and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Figures 1-2 This invention illustrates a specific embodiment of the variable frequency low-temperature air conditioning unit, including:

[0023] The compressor 1, condenser 3, check valve 5, liquid receiver 6, solenoid valve 7, throttling element 8 and evaporator 9 are connected in sequence, wherein the throttling element 8 is an electronic expansion valve;

[0024] An outdoor fan 4 is installed next to the condenser 3, and an indoor fan 10 is installed next to the evaporator 9.

[0025] A pressure sensor 2 is connected to the exhaust port of the compressor 1 to detect the high pressure at the exhaust port of the compressor 1; the refrigerant outlet of the condenser 3 is connected to the inlet of the liquid storage tank 6 through a one-way valve 5, and the outlet of the liquid storage tank 6 is connected to the throttling element 8 through a solenoid valve 7. The liquid storage tank 6 is used to store the liquid refrigerant after it has been condensed by the condenser 3.

[0026] The selection unit has its control terminal connected to pressure sensor 2, its first output terminal connected to the normal start control module, and its second output terminal connected to the low temperature start module; wherein the normal start control module is a module that uses existing technology to control the normal operation of the air conditioning unit;

[0027] The low-temperature start-up module includes a timing control unit. The output of the timing control unit is connected to the control terminal of the solenoid valve 7 and the control terminal of the electronic expansion valve 8. The control terminal of the timing control unit is connected to the second output terminal of the selection unit and the status feedback terminal of the compressor 1.

[0028] The startup process of the variable frequency low-temperature air conditioning unit described in this embodiment is as follows:

[0029] The cooling demand meets the start-up conditions, and the indoor fan 10 starts running.

[0030] The selection unit determines whether the air conditioning unit needs to execute the low-temperature start logic, that is, it determines the high pressure of the compressor 1 discharge port;

[0031] If the high pressure is greater than or equal to the predetermined pressure value Xbar, it is determined that the air conditioning unit does not need to execute the low temperature start logic, and the selection unit uses the normal start control module to enable the air conditioning unit to start normally according to the normal start logic.

[0032] If the high pressure is less than the predetermined pressure value Xbar, it is determined that the air conditioning unit needs to execute the low-temperature start-up logic. The specific process of the low-temperature start-up logic is as follows:

[0033] The selection unit controls the solenoid valve 7 and the electronic expansion valve 8 to open Y seconds in advance through the timing control unit of the low temperature start module, and the electronic expansion valve 8 maintains an idle opening to release part of the liquid refrigerant in the liquid tank 6 into the evaporator 9.

[0034] The timing control unit starts timing, controls the solenoid valve 7 to close after Y seconds, and the electronic expansion valve 8 to open to the initial degree;

[0035] After Z seconds, the normal start control module sends a command to compressor 1 to start at speed A, and compressor 1 starts running; after compressor 1 reaches the predetermined speed A, the timing control unit controls solenoid valve 7 to reopen.

[0036] Compressor 1 continues to increase its frequency to the required speed and operate normally, completing the low-temperature start-up logic.

[0037] A, X, Y, and Z are preset values.

[0038] The above embodiments of this utility model are merely illustrative examples and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations and modifications based on the above description. It is impossible to exhaustively list all possible implementations here. All obvious variations or modifications derived from the technical solutions of this utility model are still within the protection scope of this utility model.

Claims

1. A variable frequency low-temperature air conditioning unit, characterized in that, include: The compressor, condenser, check valve, liquid receiver, solenoid valve, throttling element and evaporator, selection unit, and low temperature start module are connected in sequence. A pressure sensor is connected to the compressor discharge port, and the refrigerant outlet of the condenser is connected to the liquid inlet of the liquid receiver via a check valve. The liquid outlet of the liquid receiver is connected to the throttling element via a solenoid valve. The throttling element is an electronic expansion valve. The selection unit has its control terminal connected to a pressure sensor, its first output terminal connected to a normal start control module, and its second output terminal connected to a low-temperature start module. The low-temperature start-up module includes a timing control unit. The output of the timing control unit is connected to the control terminal of the solenoid valve and the control terminal of the electronic expansion valve. The control terminal of the timing control unit is connected to the second output terminal of the selection unit and the status feedback terminal of the compressor.

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