Refrigeration and defrosting system

Abstract

The application discloses a refrigeration and defrosting system, and belongs to the technical field of refrigeration, air conditioning and heat pump equipment, which comprises a four-way valve, a condenser and an evaporator which are communicated with the four-way valve respectively, wherein the condenser and the evaporator are communicated through a pressure reduction pipeline; further comprising a compressor, wherein a high-pressure exhaust pipe of the compressor delivers refrigerant to the four-way valve, and the refrigerant is returned to the compressor through a low-pressure suction pipe of the compressor; and a pressure balance mechanism is further connected between the high-pressure exhaust pipe and the pressure reduction pipeline. The refrigeration and defrosting system can solve the problem that the four-way valve needs to be switched during defrosting, so that the four-way valve can meet the defrosting requirements of low-temperature refrigerators and low-temperature cold air, and the noise of the reversing airflow is reduced.

Description

Technical Field

[0001] This invention relates to the field of refrigeration and air conditioning heat pump equipment technology, and in particular to a refrigeration and defrosting system. Background Technology

[0002] As is well known, air conditioners require a four-way valve for defrosting and heating. However, an air conditioner's four-way valve cannot be used for defrosting while the compressor is running. Therefore, an air conditioner's four-way valve cannot be used for defrosting on low-temperature cold storage units. The reason is that the four-way valve has two pistons and two capillary tubes at its two ends. The pistons push a slider to change the direction of refrigerant flow through the pressure of the capillary tubes. There is one capillary tube on the left end and one on the right end. These two capillary tubes are supplied with refrigerant through a solenoid valve. If the left end supplies high pressure, the right end is connected to the compressor's low pressure; if the right end supplies high pressure, the left end is connected to the compressor's low pressure. As long as the pressure difference between the left and right ends reaches four kilograms, the inner piston will move and reverse the direction. If the air conditioner compressor is still running during the four-way valve switching process, the low-pressure side is low and the high-pressure side is high. In this situation, the four-way valve needs to be pressurized on the low-pressure side. However, because the pressure is too low, it cannot quickly rise above the high-pressure side by four kilograms, thus failing to create the pressure difference required for the four-way valve to function properly. Therefore, the compressor needs to stop to balance the high and low pressure difference. After the four-way valve switches, the pressure difference is quickly reached by increasing pressure on one side and decreasing pressure on the other. The reason why four-way valves are not used in cold storage or low-temperature air conditioning systems is that the low-pressure side of a cold storage unit is about four kilograms lower than that of an air conditioner. Furthermore, the orifice of a cold storage unit is smaller than that of an air conditioner, and the temperature inside is lower. Therefore, after stopping, the low and high pressure cannot be balanced quickly, requiring a longer waiting time. This longer waiting time may affect the temperature inside the cold storage unit, which is why four-way valves are not used for defrosting in cold storage.

[0003] Currently, defrosting methods in cold storage include electric defrosting, water defrosting, and high-pressure heat dissipation defrosting using compressors. These methods are inefficient, time-consuming, and energy-intensive. The high energy consumption stems from the fact that electric heating, water defrosting, and compressor heat dissipation defrosting convert one watt of electrical energy into one watt of heat energy. In contrast, the four-way valve hot-refrigerant defrosting used in air conditioners is highly efficient because air conditioner heat pumps can convert one watt of electrical energy into three watts of heat energy. However, this efficient defrosting method cannot be used in cold storage due to the characteristics of the four-way valve, which dictates its usage requirements. Therefore, how to better integrate the four-way valve with cold storage applications to meet the defrosting needs of low-temperature cold storage and low-temperature cold air is an urgent problem to be solved. Summary of the Invention

[0004] To address the shortcomings of the prior art, the present invention aims to provide a refrigeration and defrosting system that solves the problem of requiring the refrigeration system to be shut down before switching the four-way valve for defrosting. This system enables the four-way valve to allow the air conditioner to defrost without stopping, reducing defrosting time and meeting the needs of low-temperature cold storage and low-temperature cold air defrosting. At the same time, it solves the problem of refrigerant impact airflow noise caused by the reversing of the air conditioner's four-way valve.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows:

[0006] A refrigeration and defrosting system is provided, including a four-way valve and a condenser and an evaporator respectively connected thereto, wherein the condenser and the evaporator are connected through a pressure-reducing pipeline;

[0007] It also includes a compressor, wherein the high-pressure discharge pipe of the compressor delivers refrigerant to the four-way valve, and the refrigerant flows back to the compressor through the low-pressure suction pipe of the compressor;

[0008] A pressure balancing mechanism is also connected between the high-pressure exhaust pipe and the pressure-reducing pipeline.

[0009] Furthermore, the pressure balancing mechanism includes a delivery pipeline connected to a high-pressure exhaust pipe, and a first balancing solenoid valve is provided on the delivery pipeline.

[0010] Furthermore, a first throttle valve is provided on the pressure-reducing pipeline.

[0011] Furthermore, the pressure balancing mechanism also includes a balancing pipeline connected in parallel to the first throttle valve, and the balancing pipeline is connected to the delivery pipeline.

[0012] Furthermore, the balancing pipeline is equipped with a first check valve located on the condenser side and a second check valve located on the evaporator side.

[0013] Furthermore, the pressure-reducing pipeline is equipped with a third check valve located on the condenser side and a second throttle valve located on the evaporator side.

[0014] Furthermore, the pressure balancing mechanism also includes a third throttle valve connected in parallel across the two ends of the third check valve.

[0015] Furthermore, the pressure balancing mechanism also includes a second balancing solenoid valve connected in parallel across the two ends of the second throttle valve.

[0016] Furthermore, the delivery pipeline is connected to the pipeline where the third throttle valve is located.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. The refrigeration and defrosting system of the present invention can balance the pressure of the high-pressure section and the low-pressure section through the pressure balancing system, so that the four-way valve can smoothly switch directions without stopping the machine for conversion, thereby enabling the refrigeration system to meet the defrosting requirements and making it suitable for refrigeration systems such as cold storage.

[0019] 2. The refrigeration and defrosting system of the present invention reduces the defrosting time of the air conditioner and the problem of poor comfort in the air-conditioned room caused by defrosting, while also reducing the noise of the reversing airflow. Attached Figure Description

[0020] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0021] Figure 1 This is a schematic diagram of the cooling structure in Example 1.

[0022] Figure 2 The first balancing solenoid valve is opened in the cooling state of Example 1 to balance the high and low pressure difference. (Schematic diagram)

[0023] Figure 3 This is a schematic diagram of the four-way valve switching from cooling to heating in Example 1.

[0024] Figure 4 This is a schematic diagram illustrating the principle of defrosting during heating in Example 1.

[0025] Figure 5 The first balancing solenoid valve is opened in the heating and defrosting state of Example 1 to balance the high and low pressure difference. (Schematic diagram)

[0026] Figure 6 This is a schematic diagram illustrating the switching principle of the four-way valve from heating to cooling in Example 1.

[0027] Figure 7 This is a schematic diagram of the refrigeration structure in Example 2;

[0028] Figure 8 The first balancing solenoid valve is opened in the cooling state of Example 2 to balance the high and low pressure difference. (Schematic diagram)

[0029] Figure 9 This is a schematic diagram of the four-way valve switching from cooling to heating in Example 2.

[0030] Figure 10 This is a schematic diagram illustrating the principle of defrosting during heating in Example 2;

[0031] Figure 11 In Example 2, the first balancing solenoid valve is opened during the heating and defrosting state to balance the high and low pressure difference. (Schematic diagram)

[0032] Figure 12 This is a schematic diagram illustrating the switching principle of the four-way valve from heating to cooling in Example 2.

[0033] In the diagram: 1-Compressor, 1-1-High-pressure exhaust pipe, 1-2-Low-pressure suction pipe, 2-Four-way valve, 2-1-Interface 1, 2-2-Interface 2, 2-3-Interface 3, 2-4-Interface 4, 3-Condenser, 4-Evaporator, 5-Pressure reduction line, 6-First throttle valve, 7-Balancing line, 8-First check valve, 9-Second check valve, 10-First balancing solenoid valve, 11-Diverter three-way valve, 12-Delivery line, 13-Third check valve, 14-Second throttle valve, 15-Third throttle valve, 16-Second balancing solenoid valve. Detailed Implementation

[0034] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] Example 1:

[0037] like Figure 1-6 As shown, this embodiment provides a refrigeration and defrosting system, including a four-way valve 2, a condenser 3, an evaporator 4, and a compressor 1. The connection method of each part is similar to that of an air conditioning refrigeration system, and the principle is also similar to that of an air conditioning refrigeration system. In addition, the defrosting system of this embodiment can also balance the pressure between the condenser 3 and the evaporator 4 through a pressure balancing mechanism.

[0038] Specifically, the four-way valve 2 is connected to the condenser 3 and the evaporator 4 respectively, and the condenser 3 and the evaporator 4 are connected through a pressure-reducing pipe 5, which is equipped with a first throttling valve 6. The four-way valve 2 includes interface 1 2-1, interface 2-2, interface 3 2-3, and interface 4 2-4. Interface 1 2-1 is connected to the high-pressure discharge pipe 1-1 of the compressor 1, and interface 3 2-3 is connected to the low-pressure suction pipe 1-2 of the compressor 1. Interface 2 2-2 is connected to the condenser 3, and interface 4 2-4 is connected to the evaporator 4. When in cooling mode, interfaces 1 2-1 and 2-2 are connected, and interfaces 3 2-3 and 4 2-4 are connected. When in defrosting mode, interfaces 1 2-1 and 4 2-4 are connected, and interfaces 2-2 and 3 2-3 are connected. The above connection method is similar to that of an air conditioning refrigeration system and will not be described in detail here.

[0039] In this embodiment, in order to achieve pipeline pressure balance in a short time and create conditions for the switching of the four-way valve 2, so that the refrigeration system can simultaneously meet the needs of refrigeration and defrosting, a balancing pipeline 7 is also connected in parallel on the pressure-reducing pipeline 5. The balancing pipeline 7 can balance the pressure.

[0040] Specifically, the pressure-reducing pipeline 5 and the balancing pipeline 7 are connected by a diverter three-way valve 11. The balancing pipeline 7 is equipped with a first one-way valve 8 located on the condenser 3 side and a second one-way valve 9 located on the evaporator 4 side. The high-pressure exhaust pipe 1-1 is connected to a delivery pipeline 12, which is equipped with a first balancing solenoid valve 10. In this embodiment, the delivery pipeline 12 is connected to the balancing pipeline 7, and the connection point of the pipeline is also connected by a diverter three-way valve 11.

[0041] The principle of this system is as follows:

[0042] like Figure 1 During normal cooling, the system operates as follows:

[0043] like Figure 1 As shown, during normal refrigeration: Compressor 1 operates, and high-pressure refrigerant is discharged from high-pressure exhaust pipe 1-1 to four-way valve 2. It enters through port 2-1 of four-way valve 2 and flows out through port 2-2. The high-pressure refrigerant flows into condenser 3. After being cooled by heat dissipation in condenser 3, the refrigerant can be diverted to the first check valve 8 and the first throttling valve 6. Since the check valve is blocked in reverse, the high-pressure refrigerant cannot pass through the first check valve 8. After being cooled and depressurized by the first throttling valve 6, the high-pressure refrigerant can be diverted to the second check valve 9 and evaporator 4. The second check valve 9 is blocked in reverse, so the refrigerant after throttling can only enter evaporator 4. After absorbing heat in evaporator 4, it enters four-way valve 2, flows in through port 2-4 of four-way valve 2, flows out through port 2-3, and finally returns to compressor 1. Since the balance check valve is closed, high-pressure refrigerant cannot be supplied to the check valve. Therefore, the pressure in the balance line 7 is the low-pressure pressure. As long as the pressure is higher than the low-pressure pressure, the check valve will open in one direction. So as long as the first balance solenoid valve 10 is not open, the pressure in this section will always be the low-pressure pressure.

[0044] like Figure 2As shown, during defrosting to balance the high and low pressure difference: Compressor 1 is running, and high-pressure refrigerant is discharged from high-pressure exhaust pipe 1-1 to four-way valve 2. It enters through port 2-1 of four-way valve 2 and flows out through port 2-2. The high-pressure refrigerant flows into condenser 3. After being cooled by heat dissipation in condenser 3, the refrigerant is sent to the first throttling valve 6. After the first throttling valve 6 reduces the pressure and temperature, it enters evaporator 4. After evaporator 4 absorbs heat, it enters four-way valve 2 again. It flows in through port 2-4 of four-way valve 2 and flows out through port 2-3, finally returning to compressor 1. At this time, the first balancing solenoid valve 10 is open, and the high-pressure refrigerant flows through the delivery pipeline 12 to the two check valves. Since the first check valve 8 is connected to the high-pressure section, the pressure output by the first balancing solenoid valve 10 reaches equilibrium here and does not flow to this side. The second check valve 9 is connected to the low-pressure section. When the first balancing solenoid valve 10 is open, the high-pressure refrigerant flows to the low-pressure section. Due to the entry of the high-pressure section, the low-pressure section will rapidly increase in pressure, and the pressure of the evaporator 4 will increase to a state where it is balanced with the pressure of the condenser 3 or the pressure difference is small, preparing for the four-way valve 2 to switch.

[0045] like Figure 3 As shown, when the four-way valve 2 reverses: the compressor 1 is running, and the high-pressure refrigerant is discharged from the high-pressure discharge pipe 1-1 to the four-way valve 2, entering through port 2-1. Due to the reversal of the four-way valve 2 for defrosting, port 2-1 is connected to port 2-4. The high-pressure refrigerant flows from port 2-4 to the evaporator 4, and after being depressurized and cooled by the first throttling valve 6, it enters the condenser 3. From the condenser 3, the refrigerant flows from port 2-2 to port 2-3 back to the compressor 1. Whether the first balancing solenoid valve 10 is on or off has no effect on this process.

[0046] like Figure 4 As shown, the four-way valve 2 successfully reverses direction: the first balancing solenoid valve 10 is closed. At this time, the high-pressure, high-temperature refrigerant in the evaporator 4 heats the frost outside the pipes. The first balancing solenoid valve 10 is closed, the compressor 1 runs, and the high-pressure refrigerant is discharged from the high-pressure exhaust pipe 1-1 to the four-way valve 2. Due to the reversal of the four-way valve 2, defrosting occurs. At this time, interface 2-1 of the four-way valve 2 is connected to interface 2-4. The high-pressure refrigerant flows from interface 2-4 to the evaporator 4, and then splits to the second one-way valve 9 and the first throttling valve 6. Since the second one-way valve 9 is reverse-cut off, it can only flow to the first throttling valve 6. After the pressure and temperature are reduced by the first throttling valve 6, it can be split to the first one-way valve 8 and the condenser 3. Since the first one-way valve 8 is reverse-cut off, it can only flow to the condenser 3. The condenser 3 then flows from interface 2-2 to interface 3-3 back to the compressor 1.

[0047] like Figure 5As shown, after defrosting and heating ends, the system returns to cooling mode, preparing for the switching of four-way valve 2: The first balancing solenoid valve 10 opens, compressor 1 runs, and high-pressure refrigerant is discharged from high-pressure exhaust pipe 1-1 to four-way valve 2. The high-pressure refrigerant then flows from interface 4 2-4 to evaporator 4, and can then be diverted to the second one-way valve 9 and the first throttling valve 6. Because the pressure at both ends of the second one-way valve 9 is balanced, it can only flow to the first throttling valve 6. After the pressure and temperature are reduced by the first throttling valve 6, it can be diverted to the first one-way valve 8 and condenser 3. Since the first one-way valve 8 is connected to the low-pressure section, when the first balancing solenoid valve 10 opens, the high-pressure refrigerant flows to the low-pressure section. Due to the entry of high pressure, the low-pressure section rapidly increases in pressure, raising the pressure in condenser 3 to a state where it is balanced with or has a small pressure difference with evaporator 4, preparing for the switching of four-way valve 2.

[0048] like Figure 6 As shown, the four-way valve 2 successfully switched, and then the first balancing solenoid valve 10 will disconnect, restoring the original state. Figure 1 It enters the cooling state and then proceeds to the next cycle.

[0049] Example 2:

[0050] like Figure 7-12 As shown, this embodiment provides a refrigeration and defrosting system, including a four-way valve 2, a condenser 3, an evaporator 4, and a compressor 1. The connection relationship between the four-way valve 2, the condenser 3, the evaporator 4, and the compressor 1 in this embodiment is the same as in embodiment one. In addition, this embodiment also provides a pressure balancing mechanism. The pressure balancing mechanism includes a delivery pipeline 12 connected to the high-pressure exhaust pipe 1-1. A first balancing solenoid valve 10 is provided on the delivery pipeline 12.

[0051] Specifically, in this embodiment, the pressure-reducing pipeline 5 is equipped with a third one-way valve 13 located on the side of the condenser 3 and a second throttle valve 14 located on the side of the evaporator 4. The pressure balancing mechanism also includes a third throttle valve 15 connected in parallel to both ends of the third one-way valve 13 and a second balancing solenoid valve 16 connected in parallel to both ends of the second throttle valve 14. The delivery pipeline 12 is connected to the pipeline where the third throttle valve 15 is located.

[0052] Similarly, the connections at each branch pipeline are also made using a diversion tee valve 11.

[0053] The principle of this system is as follows:

[0054] like Figure 7As shown, during normal refrigeration, compressor 1 operates, and high-pressure refrigerant is discharged from high-pressure exhaust pipe 1-1 to four-way valve 2. It enters through port 2-1 and exits through port 2-2, flowing into condenser 3. After cooling down in condenser 3, it sequentially flows to third check valve 13, second throttle valve 14, and evaporator 4. After absorbing heat in evaporator 4, it re-enters four-way valve 2, flowing in through port 2-4 and out through port 2-3, finally returning to compressor 1. Due to the resistance of the throttle valve, the refrigerant flows through third check valve 13. At this time, first balancing solenoid valve 10 and second balancing solenoid valve 16 are closed, and the refrigerant does not flow through the pressure balancing mechanism. This reciprocating motion achieves refrigeration.

[0055] like Figure 8 As shown, during defrosting to balance the high and low pressure difference: Compressor 1 is running, and high-pressure refrigerant is discharged from high-pressure exhaust pipe 1-1 to four-way valve 2. It enters through port 2-1 and exits through port 2-2, flowing into condenser 3. At this time, the first balancing solenoid valve 10 and the second balancing solenoid valve 16 are open. High-pressure refrigerant flows through delivery pipe 12 to the third check valve 13 and the third throttle valve 15. Due to the resistance of the throttle valve, the refrigerant mainly passes through the third check valve 13. The refrigerant then flows to the second throttle valve 14 and the second solenoid valve. Again, due to the resistance of the throttle valve, the refrigerant mainly passes through the second solenoid valve, and then flows to evaporator 4. After absorbing heat, evaporator 4 enters four-way valve 2, flowing in through port 2-4 and out through port 2-3, finally returning to compressor 1. Because an additional refrigerant flow path is added, the pressure of evaporator 4 will increase relative to normal refrigeration. The pressure of evaporator 4 will be raised to a state where it is in balance with the pressure of condenser 3 or the pressure difference is small, in preparation for the reversal of four-way valve 2.

[0056] like Figure 9 As shown, when the four-way valve 2 reverses: Compressor 1 is running, high-pressure refrigerant is discharged from high-pressure exhaust pipe 1-1 to the four-way valve 2, entering through port 2-1. Due to the reversal of the four-way valve 2 during defrosting, port 2-1 connects to port 2-4. The high-pressure refrigerant flows from port 2-4 to the evaporator 4, then through the second throttle valve 14 and the second balancing solenoid valve 16 to the third throttle valve 15 (the third check valve 13 is not conducting in reverse). Due to the resistance of the second throttle valve 14, the refrigerant mainly passes through the second balancing solenoid valve 16, where it is depressurized and cooled before entering the condenser 3. From the condenser 3, it flows from port 2-2 to port 2-3 back to compressor 1. At this time, the unit cannot yet cool or heat normally because the first balancing solenoid valve 10 and the second balancing solenoid valve 16 are still connected, and no pressure difference is formed between the condenser 3 and the evaporator 4.

[0057] like Figure 10As shown, the four-way valve 2 successfully reverses direction: the first balancing solenoid valve 10 is closed, while the second balancing solenoid valve 16 remains open. High-pressure refrigerant is discharged from the high-pressure exhaust pipe 1-1 to the four-way valve 2, entering through port 2-1. Due to the reversal of the four-way valve 2 during defrosting, port 2-1 connects to port 2-4. The high-pressure refrigerant flows from port 2-4 to the evaporator 4, and then through the second throttling valve 14 and the second balancing solenoid valve 16 to the third throttling valve 5 (the third check valve 13 is not open in reverse). Due to the resistance of the second throttling valve 14, the refrigerant mainly passes through the second balancing solenoid valve 16, and after being depressurized and cooled by the throttling valve 15, it enters the condenser 3. From the condenser 3, the refrigerant flows from port 2-2 to port 3-3 back to the compressor 1. A pressure difference is generated between the condenser 3 and the evaporator 4, allowing the high-temperature, high-pressure refrigerant to pass through the throttling valve and become a low-temperature, low-pressure refrigerant for heat absorption and release.

[0058] like Figure 11 As shown, after defrosting and heating ends, the system returns to cooling mode, preparing for the switching of four-way valve 2: The first balancing solenoid valve 10 is opened, and the refrigerant flows in one path: the compressor 1 runs, and high-pressure refrigerant is discharged from the high-pressure exhaust pipe 1-1, reaching four-way valve 2. The high-pressure refrigerant then flows from interface 4 2-4 to the evaporator 4, and can then be diverted to the second throttle valve 14 and the second balancing solenoid valve 16. Due to the resistance of the throttle valve, it mainly flows through the solenoid valve, then to the third throttle valve 15, and finally to the condenser, before flowing back to the compressor 1 through four-way valve 2. The other path is: from the delivery pipe 12 to the condenser 3, the pressure in the condenser 3 will increase, and the pressure difference between the condenser 3 and the evaporator 4 will decrease or balance, preparing for the switching of four-way valve 2.

[0059] like Figure 12 As shown, the four-way valve 2 has successfully switched, but it cannot cool properly yet because the first balancing solenoid valve 10 and the second balancing solenoid valve 16 are still connected, and no pressure difference has been formed between the condenser 3 and the evaporator 4. Afterwards, the first balancing solenoid valve 10 and the second balancing solenoid valve 16 will close, restoring the cooling to normal. Figure 6 It enters the cooling state and then proceeds to the next cycle.

[0060] Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-mentioned technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-mentioned technical features or their equivalent features without departing from the inventive concept. For example, technical solutions formed by substituting the above-mentioned features with technical features disclosed in this application (but not limited to) that have similar functions.

Claims

1. A refrigeration and defrosting system, characterized in that, It includes a four-way valve (2) and a condenser (3) and an evaporator (4) connected to it respectively, wherein the condenser (3) and the evaporator (4) are connected through a pressure-reducing pipeline (5); It also includes a compressor (1), whose high-pressure exhaust pipe (1-1) supplies refrigerant to a four-way valve (2), and the refrigerant flows back to the compressor (1) through the low-pressure suction pipe (1-2) of the compressor (1). A pressure balancing mechanism is also connected between the high-pressure exhaust pipe (1-1) and the pressure-reducing pipeline (5). The pressure balancing mechanism includes a delivery pipeline (12) connected to the high-pressure exhaust pipe (1-1), and a first balancing solenoid valve (10) is provided on the delivery pipeline (12). The pressure reducing pipeline (5) is provided with a first throttle valve (6); the pressure balancing mechanism also includes a balancing pipeline (7) connected in parallel to the first throttle valve (6), and the pressure reducing pipeline (5) and the balancing pipeline (7) are connected by a diversion three-way valve (11); the balancing pipeline (7) is connected to the conveying pipeline (12), and the connection of the pipeline is also connected by a diversion three-way valve (11); the balancing pipeline (7) is provided with a first check valve (8) located on the side of the condenser (3) and a second check valve (9) located on the side of the evaporator (4).

2. A refrigeration and defrosting system, characterized in that, It includes a four-way valve (2) and a condenser (3) and an evaporator (4) connected to it respectively, wherein the condenser (3) and the evaporator (4) are connected through a pressure-reducing pipeline (5); It also includes a compressor (1), whose high-pressure exhaust pipe (1-1) supplies refrigerant to a four-way valve (2), and the refrigerant flows back to the compressor (1) through the low-pressure suction pipe (1-2) of the compressor (1). A pressure balancing mechanism is also connected between the high-pressure exhaust pipe (1-1) and the pressure-reducing pipeline (5). The pressure balancing mechanism includes a delivery pipeline (12) connected to the high-pressure exhaust pipe (1-1), and a first balancing solenoid valve (10) is provided on the delivery pipeline (12). The pressure reducing pipeline (5) is provided with a third check valve (13) located on the side of the condenser (3) and a second throttle valve (14) located on the side of the evaporator (4); the pressure balancing mechanism also includes a third throttle valve (15) connected in parallel to both ends of the third check valve (13); the pressure balancing mechanism also includes a second balancing solenoid valve (16) connected in parallel to both ends of the second throttle valve (14).

3. The refrigeration and defrosting system according to claim 2, characterized in that, The delivery pipeline (12) is connected to the pipeline where the third throttle valve (15) is located.

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