Double-pump liquid supply system for low-pressure refrigerant

Abstract

The utility model discloses a double-pump liquid supply system for low-pressure refrigerant, which belongs to the technical field of steam compression circulation cold water (heat pump) units, and comprises a water chilling unit system and a liquid supply pipeline system, the water chilling unit system comprises an evaporator, a compressor, a condenser and a power saver, the liquid supply pipeline system comprises a bearing liquid supply pipeline and a liquid pumping pipeline, the bearing liquid supply pipeline is from a liquid collection bag of the condenser to a bearing position of the compressor, the liquid pumping pipeline is from a liquid collection bag of the evaporator to a liquid collection bag of the condenser, a liquid supply pump is arranged in the bearing liquid supply pipeline, and a liquid pumping pump is arranged in the liquid pumping pipeline. The double-pump solution is adopted, the liquid pumping pump and the liquid supply pump are distinguished, the liquid pumping efficiency and the liquid supply efficiency are improved, stable and efficient operation of a unit is guaranteed, the problem of starting and stopping operation of the refrigerant pump in a short time is solved, and the effect of prolonging the service life of the liquid supply system is achieved.

Description

Technical Field

[0001] This utility model relates to the technical field of steam compression cycle chiller (heat pump) units, and in particular to a dual-pump liquid supply system for low-pressure refrigerant. Background Technology

[0002] Currently, driven by the policies of "carbon neutrality" and "carbon peaking", the country is paying more and more attention to energy conservation and emission reduction. The application of high-temperature heat pump units is becoming more widespread. Due to its low saturation pressure and safer and more stable system design, low-pressure refrigerant has been vigorously promoted and used in heat pump units. The new generation of HFO low-pressure environmentally friendly refrigerant, led by R1233zd(E), has been adopted by mainstream main unit manufacturers in the market.

[0003] For related technologies, please refer to the low-pressure refrigerant supply system and its control method with application number CN202411620229.5.

[0004] Regarding the aforementioned technologies, the applicant discovered that during long-term application, when using a single refrigerant pump for liquid dispensing and supply, the actuator limit switch may deviate during use, resulting in the electric ball valve failing to close fully. During liquid dispensing and supply, refrigerant leakage into the cavity causes excessively long unit start-up times, and in severe cases, the unit cannot start normally. Using an electric ball valve to switch between liquid dispensing and supply reduces the sealing performance of the ball valve after repeated opening and closing. Using a single refrigerant pump to complete the liquid dispensing and supply process requires switching between three electric valves, which complicates the control logic. Furthermore, when one ball valve malfunctions, the unit cannot start normally. These operations cause the refrigerant pump to start and stop frequently, ultimately reducing the service life of the liquid supply system. Utility Model Content

[0005] This utility model addresses the shortcomings of existing technologies by providing a dual-pump liquid supply system for low-pressure refrigerant. This application adopts a dual-pump solution, distinguishing between the liquid pump and the liquid supply pump, thereby improving the efficiency of liquid pumping and supply, ensuring stable and efficient operation of the unit, solving the problem of refrigerant pump starting and stopping in a short time, and extending the service life of the liquid supply system.

[0006] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0007] A dual-pump refrigerant supply system for low-pressure refrigerant includes a chiller system and a refrigerant supply pipeline system. The chiller system comprises an evaporator, a compressor, a condenser, and an economizer. The refrigerant supply pipeline system includes a bearing refrigerant supply pipeline and a refrigerant pumping pipeline. The bearing refrigerant supply pipeline runs from the condenser's condenser manifold to the compressor's bearing position, and the refrigerant pumping pipeline runs from the evaporator's condenser manifold to the condenser's condenser manifold. The bearing refrigerant supply pipeline is equipped with a refrigerant supply pump, and the refrigerant pumping pipeline is equipped with a refrigerant pump.

[0008] Furthermore, the liquid injection pipeline is sequentially connected to a sight glass, a manual ball valve for liquid injection, a pre-liquid injection filter, a first check valve, an exhaust solenoid valve, and a second check valve, with the liquid injection pump positioned between the pre-liquid injection filter and the first check valve.

[0009] Furthermore, the bearing fluid supply pipeline is sequentially connected to an electric ball valve for bearing fluid supply, a manual ball valve for fluid supply, a pre-supply filter, a drying filter, a fine filter, a third check valve, and a photoelectric switch, with the fluid supply pump positioned between the pre-supply filter and the drying filter.

[0010] Furthermore, the evaporator is equipped with an evaporation pressure sensor and an evaporation liquid level sensor.

[0011] Furthermore, the condenser is equipped with a condensation pressure sensor and a condensation level sensor.

[0012] Furthermore, the compressor is equipped with a bearing supply pressure sensor and a bearing outlet pressure sensor.

[0013] Furthermore, the chiller system includes a hot gas bypass valve, which is located between the evaporator and the condenser and is connected to the evaporator and the condenser respectively.

[0014] Furthermore, the chiller system includes a primary liquid supply ball valve, which is located between the condenser and the economizer and is connected to both the condenser and the economizer respectively.

[0015] Furthermore, the chiller system includes a control box, which is connected to the evaporator, compressor, and condenser via wired or wireless signals, respectively.

[0016] In summary, compared with the prior art, the beneficial effects of the above technical solution are:

[0017] (1) This application adopts a dual-pump solution, which distinguishes between the liquid pump and the liquid supply pump, improves the efficiency of liquid pumping and supply, ensures the stable and efficient operation of the unit, solves the problem of the refrigerant pump starting and stopping in a short time, and improves the service life of the liquid supply system.

[0018] (2) The design of the bearing liquid supply system should minimize the impact of refrigerant vaporization on the refrigerant pump liquid supply, reduce the friction / local resistance loss of the pipeline, ensure the net positive suction head before the refrigerant pump, and the subcooling of the refrigerant. The low-frequency operation of the refrigerant pump, the insulation of the bearing liquid supply pipeline, and the venting of the pipeline after the refrigerant pump can effectively solve the adverse effects of pipeline vaporization on the liquid supply. By controlling the bearing liquid supply system of the refrigerant pump, the system can ensure the efficient and stable operation of the chiller unit throughout its entire life cycle.

[0019] (3) By equipping the chiller system with a hot gas bypass valve, the hot gas bypass valve is fully open during the start-up phase and slowly closes after startup according to the set control cycle / control pulse, thus avoiding problems such as low evaporation pressure alarm, excessive compressor loading, and surge during the start-up phase caused by insufficient liquid supply. Attached Figure Description

[0020] Figure 1 This is an overall piping diagram of the liquid supply system in the embodiments of this application;

[0021] Figure 2 This is a piping diagram of the refrigerant pump system of the liquid supply system in the embodiments of this application;

[0022] Figure 3 This is a diagram of the liquid supply system's pre-start liquid injection pipeline in an embodiment of this application;

[0023] Figure 4 This is a diagram of the bearing fluid supply pipeline of the fluid supply system in the embodiments of this application;

[0024] Figure 5 This is a diagram of the refrigerant pump supply control logic of the liquid supply system in this application embodiment;

[0025] Figure 6 This is a control logic diagram of the liquid supply valve / hot gas bypass valve of the liquid supply system in the embodiments of this application.

[0026] Explanation of reference numerals in the attached diagram: 1. Evaporator; 1-1. Evaporation pressure sensor; 1-2. Evaporation level sensor; 2. Compressor; 2-1. Bearing supply pressure sensor; 2-2. Bearing outlet pressure sensor; 3. Condenser; 3-1. Condensation pressure sensor; 3-2. Condensation level sensor; 4. Energy saver; 5. First-stage supply ball valve; 6. Hot gas bypass valve; 7. Liquid dispensing line; 7-1. Sight glass; 7-2. Manual liquid dispensing ball valve; 7-3. Pre-dispensing filter; 7-4. Liquid dispensing pump; 7-5. First check valve; 7-6. Exhaust solenoid valve; 7-7. Second check valve; 8. Bearing supply line; 8-1. Bearing supply electric ball valve; 8-2. Supply manual ball valve; 8-3. Pre-dispensing filter; 8-4. Supply pump; 8-5. Dryer filter; 8-6. Fine filter; 8-7. Third check valve; 8-8. Photoelectric switch; 9. Control box. Detailed Implementation

[0027] The principles and features of this utility model are described below with reference to all the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0028] This utility model discloses a low-pressure refrigerant dual-pump liquid supply system.

[0029] Reference Figures 1-4A dual-pump liquid supply system for low-pressure refrigerant includes a chiller system and a liquid supply pipeline system. The chiller system consists of an evaporator 1, a compressor 2, a condenser 3, and an economizer 4. An evaporation pressure sensor 1-1 and an evaporation liquid level sensor 1-2 are connected to the evaporator 1. A condensation pressure sensor 3-1 and a condensation liquid level sensor 3-2 are connected to the condenser 3. A bearing liquid supply pressure sensor 2-1 and a bearing liquid outlet pressure sensor 2-2 are connected to the compressor 2.

[0030] The chiller system also includes a hot gas bypass valve 6, which is located between the evaporator 1 and the condenser 3 and connected to both. The chiller system also includes a primary liquid supply ball valve 5, which is located between the condenser 3 and the economizer 4 and connected to both. The chiller system also includes a control box 9, which is connected to the evaporator 1, compressor 2, and condenser 3 via wired or wireless signals.

[0031] The liquid supply system includes a bearing liquid supply line 8 and a pumping line 7. The bearing liquid supply line 8 runs from the liquid collection port of the condenser 3 to the bearing position of the compressor 2, and the pumping line 7 runs from the liquid collection port of the evaporator 1 to the liquid collection port position of the condenser 3. A liquid supply pump 8-4 is installed in the bearing liquid supply line 8, and a pumping pump 7-4 is installed in the pumping line 7. The pumping line 7 is sequentially connected to a sight glass 7-1, a manual pumping ball valve 7-2, a pre-pumping filter 7-3, a first check valve 7-5, an exhaust solenoid valve 7-6, and a second check valve 7-7. The pumping pump 7-4 is positioned between the pre-pumping filter 7-3 and the first check valve 7-5. The bearing fluid supply line 8 is sequentially connected to the bearing fluid supply electric ball valve 8-1, the fluid supply manual ball valve 8-2, the fluid supply pre-filter 8-3, the dryer filter 8-5, the fine filter 8-6, the third check valve 8-7, and the photoelectric switch 8-8. The fluid supply pump 8-4 is located between the fluid supply pre-filter 8-3 and the dryer filter 8-5.

[0032] This application adopts a dual-pump solution, distinguishing between the liquid pump 7-4 and the liquid supply pump 8-4, thereby improving the efficiency of liquid pumping and supply, ensuring the stable and efficient operation of the unit, solving the problem of refrigerant pump starting and stopping in a short time, and extending the service life of the liquid supply system.

[0033] Reference Figures 1-4 A low-pressure refrigerant dual-pump liquid supply system includes a chiller system and a liquid supply system. The chiller system consists of an evaporator 1, a condenser 3, a compressor 2, an economizer 4, a primary liquid supply ball valve 5, a hot gas bypass valve 6, and a control box 9. The liquid supply system also includes a first bearing liquid supply pipeline 8 from the liquid collector of the condenser 3 to the bearing of the compressor 2; a second bearing liquid supply pipeline 8 from the liquid collector of the condenser 3 to the bearing of the compressor 2; and a liquid pumping pipeline 7 from the liquid collector of the evaporator 1 to the liquid collector of the condenser 3.

[0034] According to the liquid supply requirements of the liquid pump 7-4 and the liquid supply pump 8-4, before the liquid pump 7-4 and the liquid supply pump 8-4 are started, there must be a net positive suction head of 0.5m in front of the pump. In the system design, the center of the condenser 3 cylinder is more than 0.5m higher than the center of the evaporator 1 cylinder.

[0035] During the startup phase of the chiller system, since the height difference between the center of the condenser 3 cylinder and the center of the evaporator 1 cylinder is more than 0.5m, and during the standby phase of the chiller system, the liquid refrigerant is mainly present in the evaporator 1, before startup, the liquid pump 7-4 needs to be used to pump liquid into the liquid collection bag of the condenser 3 to ensure that there is a sufficient supply of liquid refrigerant in the condenser 3 before startup.

[0036] In the chiller system, the hot gas bypass valve 6 is prone to insufficient refrigerant supply and low pressure of evaporator pressure sensor 1-1 during the start-up phase due to the small pressure difference of the low-pressure refrigerant supply. By equipping the chiller system with the hot gas bypass valve 6, the hot gas bypass valve 6 is fully open during the start-up phase and slowly closes according to the set control cycle / control pulse after startup. This avoids problems such as low pressure alarm of evaporator pressure sensor 1-1, excessively fast loading of compressor 2, and surge during the start-up phase caused by insufficient refrigerant supply.

[0037] Reference Figures 1-4 A low-pressure refrigerant dual-pump liquid supply system, when the system pressure difference exceeds the set upper limit of the system pressure difference during the operation of the chiller unit system, after a set delay time, the compressor 2 bearing liquid supply adopts the first bearing liquid supply pipeline 8, and the second bearing liquid supply pipeline 8 adopts the liquid supply pump 8-4 for forced liquid supply.

[0038] Before dispensing liquid, monitor the liquid level of evaporator 1. If the liquid level of evaporator 1 is lower than the set value, dispensing pump 7-4 will stop operating.

[0039] At the beginning of the liquid dispensing process, the exhaust solenoid valve 7-6 of the dispensing pump 7-4 is opened to release air. The opening and closing of the exhaust solenoid valve 7-6 is controlled by monitoring whether the operating current of the dispensing pump 7-4 reaches the set threshold.

[0040] During the liquid injection stage, the liquid injection pump 7-4 operates at a low frequency.

[0041] During the liquid dispensing process, if the liquid level in evaporator 1 does not decrease and the liquid level in condenser 3 does not increase within the set time interval, it is determined that the liquid dispensing pump 7-4 is running dry, and the number of dry runs is incremented by 1. When the cumulative number of dry runs exceeds the set value, the chiller system is locked.

[0042] After the liquid injection is completed, the second bearing liquid supply pipeline 8 is used as the bearing to supply liquid. After the supply pressure difference is greater than the set value of the supply pressure difference before startup, and after the liquid supply pump 8-4 has been running for a set time, the chiller unit system starts to run.

[0043] After the chiller unit system is started, if the system pressure difference is greater than the set upper limit of the system pressure difference, after a set delay time, the compressor 2 bearing will be supplied with liquid through the first bearing liquid supply pipeline 8.

[0044] During normal shutdown / fault shutdown / emergency shutdown, the second bearing fluid supply line 8 supplies fluid to the bearing.

[0045] The CPU module in control box 9 performs logical operations on the collected data and outputs relevant instructions to control the chiller system.

[0046] The operating principle of the low-pressure refrigerant dual-pump liquid supply system in this embodiment is as follows:

[0047] The parameters are set as follows:

[0048] The upper limit of the liquid level in condenser 3 during the liquid filling stage: Lc2;

[0049] Lower limit of condenser level 3 during liquid dispensing stage: Lc1;

[0050] Lower limit of liquid level in evaporator 1 during liquid dispensing stage: Le1;

[0051] Time for determining the operation of the dispensing pump 7-4 during the dispensing stage: ΔT1;

[0052] Operating time of the liquid supply pump 8-4 before startup: ΔT2;

[0053] After shutdown, the operating time of the liquid supply pump 8-4 is ΔT3;

[0054] Low pressure differential before startup: ΔP1;

[0055] Low pressure differential after startup: ΔP2;

[0056] System differential pressure limit: ΔP3;

[0057] System differential pressure lower limit: ΔP4;

[0058] Condenser 3 liquid level control target value: Lc3;

[0059] Hot gas bypass valve 6 control cycle: ΔT4;

[0060] Hot gas bypass valve 6 control pulse: ΔT5.

[0061] Note: Supply pressure differential = (Bearing supply pressure sensor 2-1) - (Bearing outlet pressure sensor 2-2)

[0062] System pressure difference = (condensing pressure sensor 3-1) - (evaporating pressure sensor 1-1)

[0063] Reference Figure 1 - Figure 4A low-pressure refrigerant dual-pump liquid supply system is completed by the coordinated operation of a falling film evaporator 1, a compressor 2, a condenser 3, an energy saver 4, a primary liquid supply ball valve 5, a hot gas bypass valve 6, a liquid pumping pipeline 7, a bearing liquid supply pipeline 8, and a control box 9.

[0064] Reference Figure 3 The liquid injection pipeline 7 consists of a sight glass 7-1, a manual ball valve for liquid injection 7-2, a pre-liquid injection filter 7-3, a liquid injection pump 7-4, a first check valve 7-5, an exhaust solenoid valve 7-6, and a second check valve 7-7.

[0065] Reference Figure 4 The bearing liquid supply line 8 consists of a bearing liquid supply electric ball valve 8-1, a liquid supply manual ball valve 8-2, a liquid supply pre-filter 8-3, a liquid supply pump 8-4, a dryer filter 8-5, a fine filter 8-6, a third check valve 8-7, and a photoelectric switch 8-8. Among them, the dryer filter 8-5, the fine filter 8-6, and the third check valve 8-7 constitute the first bearing liquid supply line 8. After the refrigerant completes lubrication and cooling in the bearing housing, it returns to the falling film evaporator 1.

[0066] Reference Figure 1 and Figure 5 After the chiller system receives the start command, the central processing unit of the control box 9 will collect the liquid level of the condenser 3. If the liquid level of the condenser 3 is ≥ Lc2, the liquid pump 7-4 will operate at a low frequency, the exhaust solenoid valve 7-6 will open to exhaust the liquid, and the exhaust solenoid valve 7-6 will close after the operating current of the liquid pump 7-4 reaches the set threshold. The liquid pump 7-4 will run for 60 seconds and then close. This process allows the low-temperature refrigerant in the evaporator 1 to cool the refrigerant in the liquid collection bag of the condenser 3, which is beneficial for the supply of liquid to the bearing. After the liquid pump 7-4 is closed, the liquid supply pump 8-4 will operate at a high frequency.

[0067] After the liquid supply pump 8-4 completes its operation time before startup (ΔT2), if the liquid supply pressure difference is greater than or equal to the low liquid supply pressure difference before startup (ΔP1), the chiller system will start. Otherwise, the liquid supply pump 8-4 will stop, and a report of low liquid supply pressure difference before startup will be sent, indicating a startup failure.

[0068] After the chiller system is started, if the supply pressure difference is greater than or equal to the low supply pressure difference after startup (ΔP2), the chiller system enters the running state. Otherwise, the chiller system reduces load and stops. After the liquid supply pump 8-4 runs continuously for ΔT3, the chiller system enters the standby state. If the photoelectric switch 8-8 is disconnected within ΔT3, it indicates that there is insufficient refrigerant in the liquid collection bag of condenser 3. To avoid dry running of the liquid supply pump 8-4, the bearing liquid supply electric ball valve 8-1 is opened to draw liquid from evaporator 1. After shutdown, the bearing liquid supply electric ball valve 8-1 is closed.

[0069] When the chiller system is in operation, if the system differential pressure is greater than the upper limit of the system differential pressure: ΔP3, the liquid supply pump 8-4 will be shut down; otherwise, the liquid supply pump 8-4 will continue to run.

[0070] When the chiller system is in operation, if the system differential pressure is less than the lower limit of system differential pressure: ΔP4, the liquid supply pump 8-4 will start.

[0071] When the outlet water temperature of the chiller system reaches the pause temperature, or the system is manually stopped or shut down due to a fault, the liquid supply pump 8-4 will run. After the continuous shutdown, the liquid supply pump 8-4 will run for ΔT3 hours before the chiller system enters standby mode.

[0072] After the chiller system receives the start command, the central processing unit of the control box 9 will collect the liquid level LC of the condenser 3; if the liquid level of the condenser 3 is <Lc2, the liquid pump 7-4 will operate at a low frequency, the exhaust solenoid valve 7-6 will open to exhaust the liquid, and the exhaust solenoid valve 7-6 will close after the operating current of the liquid pump 7-4 reaches the set threshold.

[0073] If, during the refrigerant pumping phase, the refrigerant pump 7-4 operates within the judgment time ΔT1, and the liquid level in evaporator 1 (Le) does not decrease or the liquid level in condenser 3 (Lc) does not increase, the refrigerant pump 6 will stop, and an alarm will be triggered indicating that the refrigerant pump 6 has been running for too long. After the fault is reset, the refrigerant pumping can be repeated. If the number of consecutive alarms is ≥5, the refrigerant pump 7-4 will be locked, and the refrigerant pump 7-4, the refrigerant pipeline 7, and the bearing supply pipeline 8 need to be inspected to confirm the cause of the alarm.

[0074] Reference Figure 1 and Figure 6 If the liquid level in condenser 3 is greater than the upper limit of the liquid level in condenser 3 during the liquid dispensing stage: Lc2, the control process will switch to the next step. In order to ensure the smooth operation of the liquid supply process of the liquid supply pump 8-4, the first-stage liquid supply ball valve 5 and the hot gas bypass valve 6 need to work together to complete the process.

[0075] After the chiller system receives the start signal, the primary liquid supply ball valve 5 is controlled according to the liquid level control target value of condenser 3: Lc3. When the actual liquid level of condenser 3 is less than or equal to the liquid level control target value of condenser 3: Lc3, the primary liquid supply ball valve 5 is closed slightly, and vice versa.

[0076] Before the chiller system receives the start signal, the hot gas bypass valve 6 is in the fully open position. After receiving the start signal, the hot gas bypass valve 6 slowly closes according to the set control cycle ΔT4 and control pulse ΔT5. This is mainly for low-pressure refrigerant chiller systems. During the start-up phase, the system pressure difference is low. When the liquid supply is insufficient, it can easily cause low alarm of evaporation pressure sensor 1-1, excessive loading of compressor 2, surge and other related problems during the start-up phase.

[0077] When the chiller system outlet water temperature reaches the pause temperature, or after manual shutdown or fault shutdown, the hot gas bypass valve 6 opens at full speed, and the primary liquid supply ball valve 5 closes at full speed to its minimum opening and remains closed. After the motor is powered off, the primary liquid supply ball valve 5 closes at full speed. After the chiller system enters standby mode, the primary liquid supply ball valve 5 closes completely, and the hot gas bypass valve 6 opens completely, preparing for the next startup.

[0078] In the above process, the CPU module in control box 9 performs logical operations on the collected data and outputs relevant instructions to control the above process.

[0079] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A dual-pump liquid supply system for low-pressure refrigerant, characterized in that: The system includes a chiller unit system and a liquid supply pipeline system. The chiller unit system consists of an evaporator (1), a compressor (2), a condenser (3), and an economizer (4). The liquid supply pipeline system includes a bearing liquid supply pipeline (8) and a liquid pumping pipeline (7). The bearing liquid supply pipeline (8) runs from the liquid collection bag of the condenser (3) to the bearing position of the compressor (2). The liquid pumping pipeline (7) runs from the liquid collection bag of the evaporator (1) to the liquid collection bag position of the condenser (3). The bearing liquid supply pipeline (8) is equipped with a liquid supply pump (8-4), and the liquid pumping pipeline (7) is equipped with a liquid pump (7-4).

2. The dual-pump liquid supply system for low-pressure refrigerant according to claim 1, characterized in that: The liquid injection pipeline (7) is sequentially connected to a sight glass (7-1), a manual ball valve for liquid injection (7-2), a pre-liquid injection filter (7-3), a first check valve (7-5), an exhaust solenoid valve (7-6), and a second check valve (7-7). The liquid injection pump (7-4) is located between the pre-liquid injection filter (7-3) and the first check valve (7-5).

3. The dual-pump liquid supply system for low-pressure refrigerant according to claim 1, characterized in that: The bearing fluid supply pipeline (8) is sequentially connected to a bearing fluid supply electric ball valve (8-1), a fluid supply manual ball valve (8-2), a fluid supply pre-filter (8-3), a dryer filter (8-5), a fine filter (8-6), a third check valve (8-7), and a photoelectric switch (8-8). The fluid supply pump (8-4) is located between the fluid supply pre-filter (8-3) and the dryer filter (8-5).

4. The dual-pump liquid supply system for low-pressure refrigerant according to claim 1, characterized in that: An evaporation pressure sensor (1-1) and an evaporation liquid level sensor (1-2) are connected to the evaporator (1).

5. A dual-pump liquid supply system for low-pressure refrigerant according to claim 1, characterized in that: The condenser (3) is connected to a condensation pressure sensor (3-1) and a condensation level sensor (3-2).

6. The dual-pump liquid supply system for low-pressure refrigerant according to claim 1, characterized in that: The compressor (2) is equipped with a bearing supply pressure sensor (2-1) and a bearing outlet pressure sensor (2-2).

7. A dual-pump liquid supply system for low-pressure refrigerant according to claim 1, characterized in that: The chiller system includes a hot gas bypass valve (6), which is located between the evaporator (1) and the condenser (3) and is connected to the evaporator (1) and the condenser (3) respectively.

8. A dual-pump liquid supply system for low-pressure refrigerant according to claim 1, characterized in that: The chiller system includes a primary liquid supply ball valve (5), which is located between the condenser (3) and the power saver (4) and is connected to the condenser (3) and the power saver (4) respectively.

9. A dual-pump liquid supply system for low-pressure refrigerant according to claim 1, characterized in that: The chiller system includes a control box (9), which is connected to the evaporator (1), compressor (2), and condenser (3) via wired or wireless signals.

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