Low-temperature refrigerating system of air conditioner

Abstract

A low-temperature refrigerating system of an air conditioner comprises a refrigerating unit, a compressor, a compressor bypass pipeline, a throttling device and an evaporator. The compressor and the compressor bypass pipeline are arranged in parallel to form a parallel pipeline, and refrigeration modes are switched and controlled through a first three-way valve and a second three-way valve which are connected to the two sides of the parallel pipeline; and an outlet of the evaporator is sequentially connected with the first three-way valve, the parallel pipeline, the second three-way valve, the refrigeration unit and the throttling device through pipelines along a refrigerant flowing path. According to the utility model, energy conservation and consumption reduction of the system can be realized, and the compressor can be prevented from entering an abnormal operation interval, so that the reliability of the compressor is improved, the downtime risk is avoided, the service life of the air-conditioning system is prolonged, and the operation and maintenance cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of air conditioners, in particular to a low-temperature refrigeration system for air conditioners. Background Technique

[0002] In recent years, the scale of data centers in China has been growing rapidly, the power density has been getting higher and higher, the heat generated by data centers has been getting larger and larger, and cooling needs to be provided throughout the year without interruption, which puts new requirements on the reliability and energy-saving level of air-conditioning equipment. An air-conditioning refrigeration system usually includes a compressor, a condenser, a throttling device and an evaporator. The refrigerant is compressed by the compressor into a high-temperature and high-pressure gas. The gas enters the condenser and condenses into a liquid refrigerant, and then is throttled and depressurized by the throttling device, enters the evaporator to absorb heat and evaporate, and then enters the compressor to form a cycle. However, the air-conditioning refrigeration system has operating range requirements. When the operating range is exceeded (especially under the condition of lower than -10°C), the air-conditioning refrigeration system may stop running due to the too-fast condensation speed of the gaseous refrigerant, resulting in the risk of downtime of the data center equipment.

[0003] At present, the main measure to solve the system downtime under low-temperature conditions is to reduce the compression ratio of the compressor. Most air-conditioning compressors are single-stage compression. The gas pressure entering the compressor from the evaporator is low. In order to obtain a lower temperature for the refrigeration system, it is easy to cause the compression ratio of single-stage compression to be too large, resulting in too low system energy efficiency and high energy consumption. However, if two-stage compression is adopted, it will also lead to an increase in system power consumption and a decrease in energy efficiency. Therefore, improving the operating reliability of the air-conditioning refrigeration system and reducing the system operating energy consumption have become urgent problems to be solved today. Content of the Utility Model

[0004] The purpose of the utility model is to overcome the above-mentioned deficiencies of the prior art and provide a low-temperature refrigeration system for air conditioners with a simple structure, which can improve the operating reliability of the system and reduce the system operating energy consumption.

[0005] The technical solution of the utility model is: a low-temperature refrigeration system for air conditioners, including a refrigeration unit, a compressor, a compressor bypass pipeline, a throttling device and an evaporator; the compressor and the compressor bypass pipeline are arranged in parallel to form a parallel pipeline, and the refrigeration mode is switched and controlled by a first three-way valve and a second three-way valve connected to both sides of the parallel pipeline; the outlet of the evaporator is connected to the first three-way valve, the parallel pipeline, the second three-way valve, the refrigeration unit and the throttling device in sequence along the refrigerant flow path.

[0006] Further, a gas-liquid separator is also provided between the outlet of the evaporator and the inlet end of the first three-way valve.

[0007] Further, the refrigeration unit is air-cooled and includes an air-cooled condenser and a condensation fan arranged on one side of the air-cooled condenser.

[0008] ​

[0009] Furthermore, the inlet end of the first three-way valve is connected to the gas-liquid separator through a pipeline, one outlet end of the first three-way valve is connected to the inlet of the compressor through a pipeline, and the other outlet end is connected to the inlet of the compressor bypass pipeline; the outlet end of the second three-way valve is connected to the refrigeration unit through a pipeline, one inlet end of the second three-way valve is connected to the outlet of the compressor, and the other inlet end is connected to the outlet of the compressor bypass pipeline.

[0010] Furthermore, a first pressure sensor for detecting the intake pressure of the compressor is provided on the pipeline between the gas-liquid separator and the first three-way valve; a second pressure sensor for detecting the outlet pressure of the compressor is provided on the pipeline between the second three-way valve and the refrigeration unit.

[0011] Furthermore, a liquid storage tank is also connected between the refrigeration unit and the throttling device, and a solenoid valve is provided at the inlet of the liquid storage tank; a liquid replenishment / drain port is provided between the refrigeration unit and the solenoid valve.

[0012] Furthermore, the height of the evaporator is lower than the height of the refrigeration unit.

[0013] Furthermore, the throttling device is an electronic expansion valve or a throttle valve, and the throttling device is connected to the inlet pipeline of the evaporator.

[0014] Furthermore, it also includes a control system and an outdoor temperature sensor for detecting the outdoor temperature. The control system is used to control the switching mode of the first three-way valve and the second three-way valve according to the comparison between the outdoor temperature detected by the outdoor temperature sensor and the preset temperature, and is also used to control the opening and closing of the solenoid valve according to the relationship between the pressure values measured by the first pressure sensor and the second pressure sensor, the high-pressure alarm value, and the low-pressure alarm value.

[0015] Advantages of the utility model:

[0016] (1) By providing a compressor bypass pipeline in parallel with the compressor and switching through two three-way valves, when the refrigeration system exceeds the operating range, the compressor can be stopped without affecting the conversion and transmission of the refrigerant, so that both system energy conservation and consumption reduction can be achieved, and the compressor can be prevented from entering the abnormal operating range, thereby increasing the reliability of the compressor, avoiding the risk of downtime, extending the service life of the air-conditioning system, and reducing the operation and maintenance costs;

[0017] (2) By providing two pressure sensors, the high-pressure value and the low-pressure value of the compressor can be obtained, so that the opening and closing of the solenoid valve can be adjusted according to the compressor pressure and the high and low pressure alarm values to adjust the liquid suction volume of the compressor, effectively suppressing the system pressure fluctuation, reducing the system downtime risk, and solving the problem that the air-conditioning equipment cannot operate under low-temperature conditions;

[0018] (3) In the ultra-low temperature mode, the self-transport of the refrigerant working medium of the system is realized through gravity and the system pressure difference, making full use of natural resources, avoiding the use of a fluorine pump, and reducing the equipment manufacturing cost. Description of the Drawings

[0019] Figure 1 It is the overall working schematic diagram of the system according to the embodiment of the present invention;

[0020] Figure 2 It is the working schematic diagram of the system in the low temperature mode according to the embodiment of the present invention;

[0021] Figure 3 It is the working schematic diagram of the system in the ultra-low temperature mode according to the embodiment of the present invention.

[0022] Description of the Reference Numerals:

[0023] 1, air-cooled condenser; 2, condensation fan; 3, liquid filling / draining port; 4, solenoid valve; 5, liquid storage tank; 6, throttling device; 7, evaporator; 8, gas-liquid separator; 9, pressure sensor A; 10, three-way valve A; 11, compressor; 12, three-way valve B; 13, pressure sensor B; 14, compressor bypass pipeline. Detailed Embodiment

[0024] The following will further describe the present invention in detail with reference to the drawings of the specification and specific embodiments.

[0025] As Figures 1 to 3 shown, an air-conditioning low-temperature refrigeration system includes an air-cooled unit, a compressor 11, a compressor bypass pipeline 14, a liquid storage tank 5, a throttling device 6, an evaporator 7 and a gas-liquid separator 8; wherein, the compressor 11 and the compressor bypass pipeline 14 are arranged in parallel, and the refrigeration mode is switched and controlled by a three-way valve A 10 and a three-way valve B 12 connected to both sides of the compressor 11 and the compressor bypass pipeline 14; and under the switching control of the three-way valve A 10 and the three-way valve B 12, the outlet of the evaporator 7 is connected in series with the gas-liquid separator 8, the three-way valve A 10, the compressor 11, the three-way valve B 12, the air-cooled unit, and the throttling device 6 along one path of the refrigerant flow, and the outlet of the evaporator 7 is connected in series with the gas-liquid separator 8, the three-way valve A 10, the compressor bypass pipeline 14, the three-way valve B 12, the air-cooled unit, and the throttling device 6 along another path of the refrigerant flow.

[0026] In this embodiment, the air-cooled unit includes an air-cooled condenser 1 and a condensation fan 2 arranged on one side of the air-cooled condenser.

[0027] In this embodiment, the inlet end of the three-way valve A10 is connected to the gas-liquid separator 8 through a pipeline. One outlet end of the three-way valve A10 is connected to the inlet of the compressor through a pipeline, and the other outlet end is connected to the inlet of the compressor bypass pipeline 14. The outlet end of the three-way valve B12 is connected to the air-cooled condenser 1 of the air-cooled unit through a pipeline. One inlet end of the three-way valve B12 is connected to the outlet of the compressor, and the other inlet end is connected to the outlet of the compressor bypass pipeline 14.

[0028] In this embodiment, a pressure sensor A9 is provided on the pipeline between the gas-liquid separator 8 and the three-way valve A10; a pressure sensor B13 is provided on the pipeline between the three-way valve B12 and the air-cooled unit; that is, the pressure sensor A9 is provided on the inlet side of the three-way valve A10; the pressure sensor B13 is provided on the outlet side of the three-way valve B12. The pressure sensor A9 is used to detect the intake pressure of the compressor, that is, to obtain the low-pressure value P2 of the compressor, and the pressure sensor B13 is used to detect the outlet pressure of the compressor, that is, to obtain the high-pressure value P1 of the compressor.

[0029] In this embodiment, a liquid storage tank 5 is further connected between the air-cooled condenser 1 and the throttling device 6. A solenoid valve 4 is provided at the inlet of the liquid storage tank. That is, the liquid storage tank 5 is arranged downstream of the air-cooled condenser 1 and upstream of the throttling device 6, and is used to adjust the pressure of the compressor 11. The liquid storage tank 5 is controlled by the solenoid valve 4. A liquid filling / draining port 3 is provided between the air-cooled condenser 1 and the solenoid valve.

[0030] In this embodiment, the refrigerant changes from a liquid state to a gaseous state in the evaporator 7, thereby reducing the indoor temperature. The gaseous refrigerant passes through the gas-liquid separator 8, the compressor 11 (or the compressor bypass pipeline 14) in sequence through the pipeline and enters the air-cooled condenser 1 to be condensed into a liquid refrigerant. The liquid refrigerant becomes a low-temperature and low-pressure refrigerant again after passing through the throttling device 6 and enters the evaporator 7 to start the next refrigeration cycle.

[0031] In this embodiment, the height of the evaporator 7 is lower than the height of the air-cooled condenser 1, so that the liquid in the air-cooled condenser 1 can flow into the evaporator 7 under the action of gravity to form the next refrigeration cycle.

[0032] In this embodiment, the throttling device 6 is an electronic expansion valve or a throttle valve. The refrigerant of the air-conditioning system can be one of Freon R22, R32, R134a, R410a or CO2.

[0033] In this embodiment, the system further includes an outdoor temperature sensor for detecting the outdoor temperature and a control system. The outdoor temperature sensor can be disposed at any position communicating with the outside. The control system is configured to control the switching modes of the three-way valve A10 and the three-way valve B12 based on the comparison between the outdoor temperature detected by the outdoor temperature sensor and a preset temperature; and is further configured to control the opening and closing of the solenoid valve 4 according to the relationship between the pressure values measured by the pressure sensor A9 and the pressure sensor B13, the high-pressure alarm value, and the low-pressure alarm value.

[0034] Specifically, the refrigeration mode is switched according to the external temperature and the compressor pressure, and is divided into a low-temperature mode and an ultra-low temperature mode. The two modes are switched and controlled by the three-way valve A10 and the three-way valve B12. The specific implementation of the two modes is as follows:

[0035] Low-temperature mode: When the external temperature > 0°C, the low-temperature mode is turned on. The liquid refrigerant absorbs heat in the evaporator 7 and is converted into a gaseous refrigerant. The gaseous refrigerant enters the gas-liquid separator 8 to separate out the liquid. Then, the low-temperature and low-pressure gaseous refrigerant is converted into a high-temperature and high-pressure gaseous refrigerant under the action of the compressor 11; the high-temperature and high-pressure gaseous refrigerant enters the air-cooled condenser 1 and is accelerated to condense into a liquid refrigerant under the action of the condensing fan 2; the liquid refrigerant passes through the throttling device 6 and becomes a low-temperature and low-pressure refrigerant again, and enters the evaporator 7 to start the next refrigeration cycle.

[0036] Ultra-low temperature mode: When the external temperature ≤ 0°C and the compressor low-pressure value P2 ≤ the low-pressure alarm value P min At this time, the compressor 11 has a risk of downtime, and the compressor 11 shuts down and stops. The ultra-low temperature mode is turned on; the three-way valve A10 and the three-way valve B12 switch directions to open the compressor bypass pipeline 14. The high-temperature and high-pressure gaseous refrigerant at the outlet of the evaporator 7 enters the air-cooled condenser 1 directly through the compressor bypass pipeline 14 after gas-liquid separation, and is condensed into a liquid refrigerant under the action of the condensing fan 2. Under the action of gravity and the system pressure difference, the liquid refrigerant passes through the throttling device 6 and becomes a low-temperature and low-pressure refrigerant again, and enters the evaporator 7 to start the next refrigeration cycle.

[0037] In this embodiment, the liquid storage tank 5 is controlled by the solenoid valve 4. The solenoid valve 4 is adjusted according to the relationship between the compressor high-pressure value P1 measured by the pressure sensor B13, the compressor low-pressure value P2 measured by the pressure sensor A9, the high-pressure alarm value P max And the low-pressure alarm value P min Among them.

[0038] The adjustment mode of the solenoid valve 4 is as follows:

[0039] 1) When P1 ≥ P max At this time, the solenoid valve 4 is opened, and the liquid storage tank 5 enters the liquid storage stage;

[0040] 2) When P2 ≤ Pmin When the time is reached, the solenoid valve 4 opens, and the liquid storage tank 5 enters the liquid replenishment stage;

[0041] 3) In other cases, the solenoid valve 4 is closed.

[0042] The liquid suction volume of the compressor 11 is adjusted through the liquid storage tank 5, effectively suppressing the system pressure fluctuation and reducing the risk of system downtime.

[0043] In summary, on the one hand, in this embodiment, by setting a compressor bypass pipeline in parallel with the compressor and switching through two three-way valves, when the refrigeration system exceeds the operating range, the compressor can stop working without affecting the conversion and transmission of the refrigerant, thereby achieving system energy conservation and consumption reduction, avoiding the compressor from entering the abnormal operating range, increasing the reliability of the compressor, avoiding the risk of downtime, prolonging the service life of the air conditioning system, and reducing the operation and maintenance costs; on the other hand, by setting two pressure sensors, the high-pressure value and low-pressure value of the compressor can be obtained, and thus the opening and closing of the solenoid valve can be adjusted according to the compressor pressure and the high and low-pressure alarm values to adjust the liquid suction volume of the compressor, effectively suppressing the system pressure fluctuation and reducing the risk of system downtime, solving the problem that the air conditioning equipment cannot operate under low-temperature conditions. In addition, in the ultra-low temperature mode, the self-transport of the system refrigerant working medium is realized through gravity and the system pressure difference, making full use of natural resources, avoiding the use of fluorine pumps, and reducing the equipment manufacturing cost.

[0044] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and modifications all fall within the scope of the present invention claimed.

Claims

1. An air conditioner low-temperature refrigeration system, characterized in that, It includes a refrigeration unit, a compressor, a compressor bypass pipeline, a throttling device and an evaporator; the compressor is arranged in parallel with the compressor bypass pipeline to form a parallel pipeline, and the refrigeration mode is switched and controlled by a first three-way valve and a second three-way valve connected to both sides of the parallel pipeline; the outlet of the evaporator is connected to the first three-way valve, the parallel pipeline, the second three-way valve, the refrigeration unit and the throttling device in sequence along the refrigerant flow path.

2. The air-conditioning low-temperature refrigeration system according to claim 1, wherein A gas-liquid separator is also provided between the outlet of the evaporator and the inlet end of the first three-way valve.

3. The air conditioner low-temperature refrigeration system according to claim 1, characterized in that, The refrigeration unit is air-cooled and includes an air-cooled condenser and a condensing fan arranged on one side of the air-cooled condenser.

4. The air conditioner low-temperature refrigeration system according to claim 2, wherein The inlet end of the first three-way valve is connected to the gas-liquid separator through a pipeline, one outlet end of the first three-way valve is connected to the inlet of the compressor through a pipeline, and the other outlet end is connected to the inlet of the compressor bypass pipeline; the outlet end of the second three-way valve is connected to the refrigeration unit through a pipeline, one inlet end of the second three-way valve is connected to the outlet of the compressor, and the other inlet end is connected to the outlet of the compressor bypass pipeline.

5. The air conditioner low-temperature refrigeration system according to claim 2, wherein, A first pressure sensor for detecting the intake pressure of the compressor is provided on the pipeline between the gas-liquid separator and the first three-way valve; a second pressure sensor for detecting the outlet pressure of the compressor is provided on the pipeline between the second three-way valve and the refrigeration unit.

6. The air conditioner low-temperature refrigeration system according to claim 3, characterized in that A liquid storage tank is also connected between the refrigeration unit and the throttling device, and a solenoid valve is provided at the inlet of the liquid storage tank; a liquid replenishment / drainage port is provided between the refrigeration unit and the solenoid valve.

7. The air conditioner low-temperature refrigeration system according to claim 1, wherein, The height of the evaporator is lower than the height of the refrigeration unit.

8. The air-conditioning low-temperature refrigeration system according to claim 1, characterized in that, The throttling device is an electronic expansion valve or a throttle valve, and the throttling device is connected to the inlet pipeline of the evaporator.

9. The air conditioner low-temperature refrigeration system according to claim 6, characterized in that, It also includes a control system and an outdoor temperature sensor for detecting the outdoor temperature. The control system is used to control the switching mode of the first three-way valve and the second three-way valve according to the comparison between the outdoor temperature detected by the outdoor temperature sensor and the preset temperature, and is also used to control the opening and closing of the solenoid valve according to the relationship between the pressure values measured by the first pressure sensor and the second pressure sensor, the high-pressure alarm value and the low-pressure alarm value.

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