Low-temperature starting system of water chilling unit

Abstract

The utility model discloses a low-temperature starting system of a water chilling unit, which belongs to the technical field of heating ventilation air conditioners and comprises refrigeration equipment, the refrigeration equipment comprises a compressor, a condenser and an evaporator, a valve component is arranged between the compressor and the condenser, and an expansion valve is arranged between the condenser and the evaporator. The compressor, the valve assembly, the condenser, the expansion valve and the evaporator are sequentially and circularly connected through a refrigerant pipeline. According to the utility model, the valve assembly and the refrigeration equipment are effectively combined, and in a low-temperature environment, the valve assembly is arranged on the exhaust pipeline of the compressor to control the exhaust pressure, so that the suction and exhaust pressure difference can be quickly established, and the normal starting effect of the water chilling unit in a low-environment-temperature condition can be achieved.

Description

Technical Field

[0001] This utility model relates to the technical field of heating, ventilation and air conditioning, and in particular to a low-temperature start-up system for a chiller unit. Background Technology

[0002] Currently, chiller units consume high-grade energy to transfer heat from a lower temperature environment to a relatively higher temperature environment. From a thermodynamic point of view, this is an entropy reversal process, so it requires external electrical energy input to achieve this.

[0003] The relevant technology involves a water chiller unit using refrigerant as the working fluid. The refrigerant is compressed into a high-temperature, high-pressure gas by the compressor and then discharged into the condenser. The condenser is cooled by air or water, liquefying the gaseous refrigerant into a liquid refrigerant. This liquid refrigerant then enters the expansion valve, where the pressure and temperature of the compressor rapidly decrease due to the throttling and pressure reduction effect. The liquid refrigerant then enters the evaporator and rapidly evaporates, absorbing heat from the working fluid being cooled. As the temperature of the cooled substance decreases, the refrigerant then re-enters the compressor to continue the cycle.

[0004] Entering the 21st century, with the improvement of living standards and rapid industrial development, chiller units have become indispensable equipment in modern life and production. For daily life and office work, they not only ensure indoor comfort but also enhance the quality of life. In the industrial field, they maintain suitable temperature and humidity for precision instruments and production workshops, contributing to the stable and efficient operation of production processes. Their core refrigeration technology is constantly innovating, intelligent control is becoming increasingly convenient, and energy saving and noise reduction are also significant. They not only meet people's pursuit of a comfortable environment but also conform to the trend of sustainable development, silently contributing a powerful force to the comfort and progress of modern society.

[0005] Regarding the aforementioned technologies, the applicant has discovered that with the continuous expansion of refrigeration demand, some special requirements have arisen in the refrigeration field, such as refrigeration needs in low-temperature environments. This places higher demands on the startup of chiller units. Ordinary chiller units have very low refrigeration efficiency in frigid regions, and with low ambient temperatures, the evaporation temperature is even lower, resulting in excessively low suction pressure. This excessively low suction pressure leads to an increase in suction specific volume, which means that under the same volume flow rate, the actual mass of refrigerant entering the compressor is reduced, resulting in low discharge pressure. This makes it impossible to establish the suction and discharge pressure difference required for the chiller unit to start up, thus causing the chiller unit to fail to start normally in low-temperature environments. Utility Model Content

[0006] This utility model addresses the shortcomings of existing technologies by providing a low-temperature start-up system for chiller units. It effectively combines valve components and refrigeration equipment. In low-temperature environments, by installing valve components on the compressor's exhaust pipe, the exhaust pressure is controlled, thereby helping to quickly establish the suction and exhaust pressure difference and complete the normal start-up of the chiller unit under low ambient temperature conditions.

[0007] The technical solution of this utility model to solve the above-mentioned technical problems is as follows:

[0008] A low-temperature start-up system for a chiller unit includes a refrigeration unit comprising a compressor, a condenser, and an evaporator. A valve assembly is provided between the compressor and the condenser, and an expansion valve is provided between the condenser and the evaporator. The compressor, valve assembly, condenser, expansion valve, and evaporator are sequentially connected through refrigerant pipelines.

[0009] Furthermore, the valve assembly includes an electric ball valve, which is connected between the compressor and the condenser via a refrigerant line.

[0010] Furthermore, the valve assembly includes a solenoid valve and a check valve, which are interconnected and connected between the compressor and the condenser via a refrigerant line.

[0011] Furthermore, the valve assembly includes a pressure maintaining valve, which is connected between the compressor and the condenser via a refrigerant line.

[0012] Furthermore, the compressor is equipped with an intake pressure sensor at the intake end and an exhaust pressure sensor at the exhaust end.

[0013] Furthermore, the valve assembly is equipped with a control module, which may include a PLC, a microcontroller, or its own mechanical structure.

[0014] Furthermore, the evaporator is equipped with an ejector pump, which sequentially connects the compressor, valve assembly, condenser, expansion valve and evaporator through lubrication lines.

[0015] In summary, compared with the prior art, the beneficial effects of the above technical solution are:

[0016] (1) This application effectively combines valve components and refrigeration equipment. In low-temperature environments, by installing valve components on the exhaust pipe of the compressor, the magnitude of the exhaust pressure is controlled, thereby helping to quickly establish the suction and exhaust pressure difference and complete the normal start-up of the chiller unit under low ambient temperature conditions.

[0017] (2) This application can be matched with different valve components according to the specific application scenario of the chiller unit. The opening degree of the electric ball valve controlled by PLC can be controlled in real time, or the switching frequency of the solenoid valve controlled by PLC can be controlled. Alternatively, a traditional mechanical pressure maintaining valve can be used to control the exhaust pressure under the action of pressure difference. This application is not only applicable to PLC control method, but also to common control methods such as single-chip microcomputer.

[0018] (3) This application has a wide range of applications and can achieve good results for different types of chiller units. At the same time, it has a simple structure, is stable and reliable, and can achieve stable start-up of the unit without complicated operation.

[0019] (4) This application is applicable to water chillers and heat pump units, and can help to quickly establish suction and discharge pressure difference to supply oil to the compressor in a timely manner.

[0020] (5) This application is not limited by the type of refrigerant. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the working principle of this utility model;

[0022] Figure 2 This is a schematic diagram illustrating the working principle of Embodiment 1 of this utility model;

[0023] Figure 3 This is a schematic diagram illustrating the working principle of Embodiment 2 of this utility model;

[0024] Figure 4 This is a schematic diagram illustrating the working principle of Embodiment 3 of this utility model;

[0025] Figure 5 This is a flow chart of the chiller unit circulation of this utility model.

[0026] Explanation of reference numerals in the attached diagram: 1. Compressor; 11. Suction pressure sensor; 12. Discharge pressure sensor; 2. Valve assembly; 21. Electric ball valve; 22. Solenoid valve; 23. Check valve; 24. Pressure maintaining valve; 3. Condenser; 4. Expansion valve; 5. Evaporator. 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-temperature start-up system for a chiller unit. The following embodiments only describe the main components and equipment for the normal operation of the chiller unit, but are also applicable to chiller units with other auxiliary equipment, and do not limit the type of refrigerant. Through improvements to the design of the low-temperature start-up system for the chiller unit, a valve assembly 2 for exhaust pressure control is proposed, effectively solving the problem of difficulty in establishing a pressure difference between suction and exhaust pressures in the chiller unit under low ambient temperature cooling mode.

[0029] Example 1

[0030] Reference Figure 1 , Figure 2 and Figure 5 A low-temperature start-up system for a chiller unit includes refrigeration equipment, which comprises a compressor 1, a condenser 3, and an evaporator 5. A valve assembly 2 is provided between the compressor 1 and the condenser 3. The valve assembly 2 is installed between the compressor 1 and the condenser 3 and serves to control the discharge pressure. It is also suitable for connecting the valve assembly 2 to other equipment, ensuring that its installation position between the compressor 1 and the condenser 3 is sufficient to regulate the discharge pressure.

[0031] An expansion valve 4 is installed between the condenser 3 and the evaporator 5. The compressor 1, valve assembly 2, condenser 3, expansion valve 4, and evaporator 5 are sequentially connected via refrigerant piping. It should be noted that the above components and equipment are only the basic components of refrigeration equipment; they are also applicable to chiller units containing other auxiliary equipment or parts. Other refrigeration equipment components and equipment are not described in detail here. This application effectively combines the valve assembly 2 with the refrigeration equipment. In low-temperature environments, by installing the valve assembly 2 on the exhaust pipe of the compressor 1, the exhaust pressure is controlled, thereby helping to quickly establish the suction and exhaust pressure difference and complete the normal start-up of the chiller unit under low ambient temperature conditions.

[0032] The main function of adding valve assembly 2 to the pipe at the discharge end of compressor 1 is to increase the discharge pressure at the discharge end of compressor 1 by preventing the flow of gaseous refrigerant. In extremely cold environments, valve assembly 2 is closed or has a very small opening when the chiller unit starts up. After compressor 1 starts, gaseous refrigerant accumulates at the discharge end pipe, and the discharge pressure increases. When the discharge pressure rises to a level sufficient to establish a normal discharge pressure, valve assembly 2 opens or increases its opening. During normal operation of the chiller unit, valve assembly 2 is in the fully open state; when the chiller unit is shut down, valve assembly 2 is in the closed state.

[0033] In this embodiment, the valve assembly 2 includes an electric ball valve 21, which is connected between the compressor 1 and the condenser 3 via a refrigerant pipeline. The electric ball valve 21 can be installed in a location that is not directly connected to the compressor 1 and the condenser 3, and is also applicable to other equipment, as long as the installation location is between the compressor 1 and the condenser 3, and it can play a role in regulating the discharge pressure.

[0034] The compressor 1 is equipped with a suction pressure sensor 11 at the suction end and a discharge pressure sensor 12 at the discharge end.

[0035] Valve assembly 2 is equipped with a control module, which may include a PLC, a microcontroller, or its own mechanical structure. In this embodiment, the control module can be a PLC or a microcontroller. This embodiment can use the PLC to control the opening degree of the electric ball valve 21, or control the switching frequency of the electric ball valve 21 through the PLC, to control the exhaust pressure in real time. The exhaust pressure is controlled under the action of pressure difference. This application is not only applicable to PLC control methods, but also to common control methods such as microcontrollers.

[0036] Evaporator 5 is equipped with an ejector pump, which connects compressor 1, valve assembly 2, condenser 3, expansion valve 4 and evaporator 5 in sequence through lubrication pipeline.

[0037] In cooling mode, the chiller unit operates with the compressor 1's discharge end connected to the inlet of the electronic ball valve, the compressor 1's suction end connected to the evaporator 5, and the compressor 1's oil return port connected to the oil drain pipe at the bottom of the evaporator 5. The PLC controls the electric ball valve 21 by setting a suction / discharge pressure difference setpoint. When the suction / discharge pressure difference has not reached the setpoint, the electric ball valve 21 opens to its minimum. Once the suction / discharge pressure difference is established, the electric ball valve 21 opens further. The electric ball valve 21 helps the chiller unit quickly establish a suction / discharge pressure difference, allowing the lubricating oil in the evaporator 5 to be ejected back into the compressor 1 through the ejector pump under the action of the suction / discharge pressure difference, ensuring reliable lubrication of the compressor 1 and preventing wear or malfunction. The chiller unit then starts normally.

[0038] This application has wide applications and can effectively work on various types of chiller units. It features a simple structure, stability, and reliability, enabling stable start-up of the unit without complex operations. Applied to chiller units, it is also suitable for heat pump units, helping to quickly establish a suction and discharge pressure difference, ensuring timely oil supply to compressor 1. Furthermore, the type of refrigerant is not limited.

[0039] 2. Valve assembly 2, which controls the circulation and discharge pressure of the refrigeration system. The valves temporarily isolate the refrigeration system, and by controlling the valves, the refrigeration unit can quickly increase the discharge pressure, establish a suction and discharge pressure difference, and achieve normal startup of the chiller unit. In cooling mode, the chiller unit consumes high-grade energy to transfer heat from the low-temperature environment to the high-temperature external environment.

[0040] A valve assembly 2 is added to the discharge end pipe of compressor 1 to control the discharge pressure and establish a suction and discharge pressure difference. When the chiller unit is first started, the valve assembly 2 is in the closed state or the opening degree is very small, so that the chiller unit establishes a suction and discharge pressure difference. When the suction and discharge pressure difference required by the chiller unit is reached, the valve assembly 2 opens or the opening degree increases, and the refrigerant pipeline completes normal circulation in the refrigeration system. After the suction and discharge pressure difference reaches the normal value, the lubricating oil is pumped by the ejector pump and drawn back to the suction end of compressor 1 to lubricate the inside of compressor 1, thus completing the normal start-up of the chiller unit under low ambient temperature conditions.

[0041] The implementation principle of Example 1 is as follows:

[0042] Low-temperature, low-pressure refrigerant enters compressor 1 from the suction end a. Driven by a motor, compressor 1 compresses the refrigerant, transforming it into a high-temperature, high-pressure gaseous refrigerant, which is discharged from the discharge end b. The refrigerant then reaches the inlet end c of electric ball valve 21. During the initial startup of the chiller unit, the opening of electric ball valve 21 is linearly related to the pressure difference between the chiller unit's suction and discharge. The PLC calculates the pressure difference using suction pressure sensor 11 and discharge pressure sensor 12, and controls the opening of electric ball valve 21 in real time, thus controlling the pressure difference. Once the required pressure difference for normal chiller unit startup is reached, electric ball valve 21 fully opens or increases its opening, allowing refrigerant to be discharged from the outlet end d, and the chiller unit begins normal operation. The gaseous refrigerant enters condenser 3 from the inlet end e for cooling, liquefying into a high-pressure, low-temperature liquid refrigerant, which is then discharged from the outlet end f of condenser 3. Upon reaching the inlet g of expansion valve 4, under the throttling and pressure reduction effect of expansion valve 4, the high-pressure, low-temperature liquid refrigerant becomes a low-temperature, low-pressure liquid refrigerant, which is discharged from the outlet h of expansion valve 4 and enters evaporator 5 from the inlet i of evaporator 5. The low-temperature, low-pressure liquid refrigerant rapidly evaporates and absorbs heat in evaporator 5, becoming a low-pressure, low-temperature gaseous refrigerant, which is discharged from the outlet j of evaporator 5 and re-enters compressor 1 through suction pressure sensor 11 to continue the cycle.

[0043] Example 2

[0044] Reference Figure 1 , Figure 3 and Figure 5 The difference between this embodiment and embodiment 1 lies in the valve assembly 2.

[0045] Valve assembly 2 includes a solenoid valve 22 and a check valve 23. The solenoid valve 22 and the check valve 23 are connected to each other and are connected between the compressor 1 and the condenser 3 through a refrigerant pipeline.

[0046] The installation positions of the solenoid valve 22 and check valve 23 do not need to be directly connected to the compressor 1 and condenser 3. They are also suitable for connection with other equipment. As long as the installation position is between the compressor 1 and condenser 3, they can play the role of regulating and controlling the exhaust pressure.

[0047] This application can be combined with different valve components 2 according to the specific application scenario of the chiller unit. The opening degree of the solenoid valve 22 and check valve 23 controlled by PLC can be used, or the switching frequency of the solenoid valve 22 and check valve 23 can be controlled by PLC to control the exhaust pressure in real time. The exhaust pressure is controlled under the action of pressure difference. This application is not only applicable to PLC control method, but also to common control methods such as microcontroller.

[0048] In the chiller unit's cooling mode, the compressor 1's discharge port is connected to the inlet of solenoid valve 22, the solenoid valve 22's outlet is connected to check valve 23, the check valve 23's discharge port is connected to condenser 3, the compressor 1's suction port is connected to evaporator 5, and the oil return pipe at the bottom of evaporator 5 is connected to compressor 1's suction pipe. The PLC controls the opening and closing of solenoid valve 22 to control the suction and discharge pressure difference. When the suction and discharge pressure difference reaches the set value, solenoid valve 22 opens, allowing refrigerant to flow normally and completing the refrigeration cycle. Under the influence of the suction and discharge pressure difference, the lubricating oil at the bottom of evaporator 5 is ejected back to compressor 1 by an ejector pump, thus lubricating compressor 1. At this point, the chiller unit completes its normal startup.

[0049] A solenoid valve 22 and a check valve 23 are added to the discharge end pipeline of compressor 1 to control the discharge pressure and establish a suction and discharge pressure difference. When the chiller unit is first started, the solenoid valve 22 and the check valve 23 are in the closed state or have a very small opening, so that the chiller unit establishes a suction and discharge pressure difference. When the suction and discharge pressure difference required by the chiller unit is reached, the solenoid valve 22 and the check valve 23 open or increase their opening, and the refrigerant pipeline completes normal circulation in the refrigeration system. After the suction and discharge pressure difference reaches the normal value, the lubricating oil is pumped by the ejector pump and drawn back to the suction end of compressor 1 to lubricate the inside of compressor 1, thus completing the normal start-up of the chiller unit under low ambient temperature conditions.

[0050] The implementation principle of Example 2 is as follows:

[0051] Low-temperature, low-pressure refrigerant enters compressor 1 from the suction end a. Driven by a motor, compressor 1 compresses the refrigerant, transforming it into a high-temperature, high-pressure gaseous refrigerant, which is then discharged from the discharge end b. The gas passes through the discharge pressure sensor 12 and reaches the solenoid valve 22. When the refrigeration unit is first started, the suction and discharge pressure difference cannot be established. At this time, the PLC controls the solenoid valve 22, keeping it closed. By controlling the switching frequency of the solenoid valve 22, the discharge pressure of compressor 1 is controlled. Simultaneously, the one-way valve 23 prevents refrigerant backflow caused by low discharge pressure. Once the suction and discharge pressure difference is established, solenoid valve 22 is in the open state. Gaseous refrigerant is discharged from end d of solenoid valve 22, flows into inlet e of check valve 23, and then flows out from port f after passing through check valve 23. It then flows into condenser 3 from inlet g and exchanges heat with the condensing medium for cooling. The gaseous refrigerant liquefies into high-pressure, low-temperature liquid refrigerant, which is discharged from outlet h and enters expansion valve 4 from inlet i. Under the throttling and pressure reduction effect of expansion valve 4, the high-pressure, low-temperature liquid refrigerant becomes low-temperature, low-pressure liquid refrigerant, which is discharged from outlet j and enters evaporator 5 from inlet k. The low-temperature, low-pressure liquid refrigerant rapidly evaporates and absorbs heat in evaporator 5, reducing the temperature of the refrigerant. At this time, the refrigerant vaporizes into low-temperature, low-pressure gaseous refrigerant, which is discharged from outlet l of evaporator 5 and re-enters compressor 1 through suction pressure sensor 11 to continue the refrigeration cycle.

[0052] Example 3

[0053] Reference Figure 1 , Figure 4 and Figure 5 The difference between this embodiment and embodiment 1 lies in the valve assembly 2.

[0054] Valve assembly 2 includes a pressure maintaining valve 24, which is connected between compressor 1 and condenser 3 via a refrigerant line.

[0055] The pressure maintaining valve 24 can be installed in a position that is not directly connected to the compressor 1 and the condenser 3. It can be used to connect with other equipment. As long as the installation position is between the compressor 1 and the condenser 3, it can play the role of regulating and controlling the exhaust pressure.

[0056] This application can be matched with different pressure maintaining valves 24 according to the specific application scenario of the chiller unit. The traditional mechanical pressure maintaining valve 24 is used to control the exhaust pressure under the action of pressure difference.

[0057] In the chiller unit's cooling mode, the compressor 1's discharge port is connected to the bottom inlet of pressure maintaining valve 24, the top of pressure maintaining valve 24 is connected to the compressor 1's suction port, and the side is connected to condenser 3. The oil return pipe at the bottom of evaporator 5 is connected to the compressor 1's suction pipe. After compressor 1 starts, gaseous refrigerant reaches pressure maintaining valve 24. At this time, the discharge pressure is lower than the combined force of the spring force and suction pressure of pressure maintaining valve 24, so pressure maintaining valve 24 is closed. Once the discharge pressure is greater than the combined force of the spring force and suction pressure, the discharge pressure opens the valve head of pressure maintaining valve 24, allowing refrigerant to flow normally into condenser 3. At this time, under the action of the suction and discharge pressure difference, the lubricating oil at the bottom of evaporator 5 returns to compressor 1 through an oil return ejector, completing the lubrication of compressor 1, and the chiller unit starts up.

[0058] A pressure maintaining valve 24 is added to the discharge end pipeline of compressor 1 to control the discharge pressure and establish a suction and discharge pressure difference. When the chiller unit is first started, the pressure maintaining valve 24 is in the closed state or the opening degree is very small, so that the chiller unit establishes a suction and discharge pressure difference. When the suction and discharge pressure difference required by the chiller unit is reached, the pressure maintaining valve 24 opens or the opening degree increases, and the refrigerant pipeline completes normal circulation in the refrigeration system. After the suction and discharge pressure difference reaches the normal value, the lubricating oil is pumped by the ejector pump and drawn back to the suction end of compressor 1 to lubricate the inside of compressor 1, thus completing the normal start-up of the chiller unit under low ambient temperature conditions.

[0059] The implementation principle of Example 3 is as follows:

[0060] Low-temperature, low-pressure refrigerant enters compressor 1 from the suction end a. Under the drive of the motor, compressor 1 compresses the refrigerant, turning it into a high-temperature, high-pressure gaseous refrigerant. It is discharged from the discharge end b of compressor 1, passes through the discharge pressure sensor 12, and reaches the inlet end c of pressure maintaining valve 24. Pressure maintaining valve 24 is not controlled by PLC, but by its own mechanical structure. The top of the pressure maintaining valve 24 is connected to the suction pipe of compressor 1 via a capillary tube, the bottom is connected to the discharge pipe of compressor 1, and the side is connected to the suction port c of condenser 3. When the discharge pressure of compressor 1 is greater than the combined force of the spring force inside the pressure maintaining valve 24 and the suction pressure, the valve head is opened under the action of the discharge pressure. At this time, the gaseous refrigerant is discharged smoothly from the outlet e of the pressure maintaining valve 24 and enters condenser 3 from port f. After condensation, the refrigerant liquefies from gaseous refrigerant into high-pressure, low-temperature liquid refrigerant, which is discharged from the outlet g and enters expansion valve 4 from port h. After the expansion valve 4 throttles and reduces pressure, it is discharged from the outlet i. Through heat exchange with the refrigerant at the inlet j of evaporator 5, the refrigerant vaporizes into low-temperature, low-pressure gaseous refrigerant, which is discharged from the outlet k and returns to compressor 1 through suction pressure sensor 11 to continue the cycle.

[0061] 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 water chiller low temperature start-up system comprising a refrigeration apparatus including a compressor (1), a condenser (3) and an evaporator (5), characterized in that: A valve assembly (2) is provided between the compressor (1) and the condenser (3), and an expansion valve (4) is provided between the condenser (3) and the evaporator (5). The compressor (1), valve assembly (2), condenser (3), expansion valve (4) and evaporator (5) are sequentially connected through refrigerant pipelines.

2. The low-temperature starting system of a water chiller unit according to claim 1, characterized in that: The valve assembly (2) includes an electric ball valve (21), which is connected between the compressor (1) and the condenser (3) via a refrigerant line.

3. The low-temperature starting system of a water chiller unit according to claim 1, wherein: The valve assembly (2) includes a solenoid valve (22) and a check valve (23). The solenoid valve (22) and the check valve (23) are connected to each other. The solenoid valve (22) and the check valve (23) are connected between the compressor (1) and the condenser (3) through a refrigerant pipeline.

4. The water chiller low-temperature starting system according to claim 1, characterized in that: The valve assembly (2) includes a pressure maintaining valve (24), which is connected between the compressor (1) and the condenser (3) via a refrigerant line.

5. A low-temperature start-up system for a chiller unit according to claim 1, characterized in that: The compressor (1) is equipped with an intake pressure sensor (11) at the intake end and an exhaust pressure sensor (12) at the exhaust end.

6. A water chiller low temperature start-up system as claimed in claim 1, wherein: The valve assembly (2) is equipped with a control module, which may include a PLC, a microcontroller, or its own mechanical structure.

7. The water chiller low-temperature starting system according to claim 1, characterized in that: The evaporator (5) is equipped with an ejector pump, which sequentially connects the compressor (1), valve assembly (2), condenser (3), expansion valve (4) and evaporator (5) through a lubrication pipeline.

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