A refrigeration system for transport

Abstract

The utility model discloses a refrigerating system for transportation solves the problem of insufficient refrigerating capacity and defrosting difficulty under freezing mode in the prior art. The refrigerating system for transportation of the utility model includes compressor, condenser, expansion valve and evaporator, still includes regenerator, gas-liquid separation type liquid distribution head and gas bypass valve, is equipped with second solenoid valve between compressor and condenser, is equipped with third solenoid valve between compressor and gas-liquid separation type liquid distribution head, is equipped with fourth solenoid valve between compressor and evaporator. The exhaust port of refrigeration compressor is connected with second solenoid valve import, third solenoid valve import, fourth solenoid valve import respectively, and the outlet of second solenoid valve is connected with the import of condenser; the outlet of third solenoid valve is connected with the import of gas-liquid separation type liquid distribution head, and the outlet of fourth solenoid valve is connected with the outlet of evaporator; the gas-liquid separation type liquid distribution head of the utility model is changed through the liquid distribution head structure, makes the refrigerant even distribution into evaporator, improves the refrigeration efficiency.

Description

Technical Field

[0001] This utility model relates to the field of refrigeration technology for refrigerated trucks, and in particular to a refrigeration system for transportation. Background Technology

[0002] With the rapid development of the social economy, the cold chain logistics industry is booming. Refrigerated trucks, as an indispensable key transportation tool in cold chain logistics, are widely used for transporting various goods requiring low-temperature preservation, such as food, medicine, and fresh produce. The refrigeration unit, as the core component of the refrigerated truck, directly affects the transportation quality and efficiency. However, as the required cooling temperature of refrigerated trucks decreases, the cooling effect of conventional refrigeration units deteriorates. After throttling, the refrigerant contains more gas than liquid, resulting in insufficient utilization of the evaporator area.

[0003] In low-temperature environments, evaporators are prone to frosting. This is because when the ambient temperature is low, the surface temperature of the evaporator also decreases accordingly, causing water vapor in the air to condense into frost upon contact with the cold evaporator surface. Evaporator frosting reduces its heat exchange efficiency and refrigeration effect, consequently affecting the temperature stability inside the refrigerated truck and the preservation quality of goods. Removing frost from the evaporator typically requires regular manual defrosting or electric defrosting, but these methods are not only cumbersome and time-consuming, but may also damage goods, while increasing energy consumption and operating costs. Utility Model Content

[0004] To address the shortcomings in the aforementioned background technology, this utility model proposes a refrigeration system for transportation, which solves the problems of insufficient cooling capacity and low defrosting efficiency in the existing technology under freezing mode.

[0005] The technical solution of this utility model is implemented as follows: a refrigeration system for transportation includes a compressor, a condenser, an expansion valve and an evaporator, and also includes a regenerator, a gas-liquid separation type distributor and a gas bypass valve. A first solenoid valve is provided between the evaporator and the regenerator, a second solenoid valve is provided between the compressor and the condenser, a third solenoid valve is provided between the compressor and the gas-liquid separation type distributor, and a fourth solenoid valve is provided between the compressor and the evaporator. Specifically, the exhaust port of the refrigeration compressor is connected to the inlet of the second, third, and fourth solenoid valves, respectively; the outlet of the second solenoid valve is connected to the condenser inlet; the outlet of the third solenoid valve is connected to the inlet of the gas-liquid separator; and the outlet of the fourth solenoid valve is connected to the evaporator outlet. The condenser outlet is connected to the lower shell-side inlet of the regenerator; the upper shell-side inlet of the regenerator is connected to the outlet of the gas bypass valve and the outlet of the first solenoid valve, respectively. The upper shell-side outlet of the regenerator is connected to the inlet of the expansion valve; the outlet of the expansion valve is connected to the inlet of the gas-liquid separator; the liquid separation orifice of the gas-liquid separator is connected to the evaporator inlet; and the gas separation orifice of the gas-liquid separator is connected to the gas bypass valve inlet. The evaporator outlet is connected to the inlet of the first and fourth solenoid valves; the gas bypass valve outlet is connected to the outlet of the first solenoid valve and the upper shell-side inlet of the regenerator; and the upper shell-side outlet of the regenerator is connected to the refrigeration compressor suction port. This invention utilizes the gas bypass function of a gas-liquid separation type liquid separator head to enable refrigerated trucks to adapt to various extreme environmental requirements, effectively solving the problem of insufficient cooling capacity in freezing mode, which is of great significance to the development of the refrigerated truck industry.

[0006] Further optimization: the gas-liquid separation type liquid separator includes a cylindrical gas collection chamber and a conical liquid collection chamber. A gas-liquid separation baffle is provided between the gas collection chamber and the liquid collection chamber. An inlet is provided on the liquid collection chamber, and a gas separation hole and a liquid separation hole are provided on the gas collection chamber.

[0007] Further optimization involves providing a gas separation hole and several liquid separation holes on the gas collection chamber; the gas separation hole is located in the middle of the gas collection chamber and corresponds to the gas-liquid separation baffle above and below; the several liquid separation holes are evenly distributed on a circle centered on the gas separation hole.

[0008] Further optimization involves an internal coil inside the regenerator. The inlet of the internal coil is connected to the lower inlet on the shell side of the regenerator, and the outlet of the internal coil is connected to the upper outlet on the shell side of the regenerator.

[0009] Further optimization involves a regenerator comprising a shell, with an internal coil embedded within the shell. The lower shell-side inlet is located at the bottom of the shell, while the upper shell-side outlet, upper shell-side inlet, and upper shell-side outlet are located at the top of the shell.

[0010] Further optimization includes a liquid receiver tank for transport, with the condenser outlet connected to the liquid receiver tank inlet; the liquid receiver tank outlet is also connected to the lower shell-side inlet of the regenerator. The liquid receiver tank, located at the condenser outlet, stores and regulates excess liquid refrigerant in the system, ensuring a continuous, bubble-free, high-pressure liquid flow to the expansion valve under any operating condition, while also accommodating refrigerant migration caused by changes in operating conditions.

[0011] Further optimization includes an oil separator in the refrigeration system for transportation. The discharge port of the refrigeration compressor is connected to the inlet of the oil separator, and the outlet of the oil separator is connected to the inlets of the second, third, and fourth solenoid valves, respectively. The oil separator is positioned between the compressor discharge port and the condenser inlet to quickly separate the lubricating oil flushed out with the high-pressure exhaust and return it to the compressor crankcase. This ensures efficient heat exchange in the condenser and evaporator while preventing oil shortage in the compressor.

[0012] As a preferred option, the regenerator can be any one of a plate heat exchanger, a regenerator-type economizer, or a flash economizer.

[0013] As a preferred embodiment, the condenser and evaporator are any one of the following: finned tube heat exchanger, stacked heat exchanger, and parallel flow heat exchanger.

[0014] As a preferred option, the expansion valve is any one of the following: manual expansion valve, flow-blocking expansion valve, float expansion valve, thermostatic expansion valve, and electronic expansion valve.

[0015] The beneficial effects of this utility model are as follows: The gas-liquid separation type distributor head adopted by this utility model can evenly distribute the refrigerant to each pipeline of the evaporator by changing the structure of the distributor head, thereby increasing the effective utilization area of ​​the evaporator; it solves the problems of insufficient cooling capacity, reduced cooling efficiency, and insufficient utilization of evaporator area in the freezing mode of refrigerated trucks; moreover, through the gas bypass function of the gas-liquid separation type distributor head, refrigerated trucks can adapt to various extreme environmental requirements, which is of great significance to the development of the refrigerated truck industry.

[0016] This invention enables hot gas bypass defrosting, which utilizes the high-temperature, high-pressure refrigerant gas discharged from the compressor to directly enter the evaporator for defrosting. This high-temperature, high-pressure refrigerant gas has high heat, which can quickly melt the frost layer on the evaporator surface. Hot gas bypass defrosting can evenly transfer heat to all parts of the evaporator, including the evaporator fins and the inside of the pipes, which can more thoroughly remove the frost layer and improve defrosting efficiency.

[0017] This invention can also employ a reverse hot gas bypass defrosting mode. In reverse hot gas bypass defrosting, the high-temperature and high-pressure refrigerant gas discharged from the compressor enters the evaporator outlet and begins to defrost the frost layer in reverse from the evaporator outlet, thereby achieving the purpose of efficient defrosting.

[0018] In summary, the refrigeration system of this utility model is a high-efficiency and energy-saving transportation refrigeration system that adopts a gas-liquid separation type liquid distributor. It can be widely used in various refrigerated trucks, various cold storage facilities, and various scenarios for low-temperature refrigeration; it has high promotional value. Attached Figure Description

[0019] To more clearly illustrate the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the refrigeration system of this utility model;

[0021] Figure 2 This is a schematic diagram of the gas-liquid separation type liquid separator of this utility model;

[0022] Figure 3 A flowchart of the refrigeration system's refrigeration operation mode;

[0023] Figure 4 Flowchart of the defrosting operation mode of the refrigeration system;

[0024] Figure 5 This is a flowchart of the reverse hot gas bypass defrosting working mode of the refrigeration unit. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] Example 1, such as Figure 1As shown, a refrigeration system for transportation includes a compressor 1, a condenser 3, an expansion valve 7, and an evaporator 9. These four components are essential to a basic refrigeration system. The condenser 3 and evaporator 9 are any one of a finned-tube heat exchanger, a stacked heat exchanger, or a parallel-flow heat exchanger. The expansion valve 7 is any one of a manual expansion valve, a flow-restricted expansion valve, a float-type expansion valve, a thermostatic expansion valve, or an electronic expansion valve. The compressor 1 is any one of a fixed-frequency refrigeration compressor, a variable-speed refrigeration compressor, a digital scroll compressor, or a two-stage refrigeration compressor. The compressor compresses low-temperature, low-pressure gas into high-temperature, high-pressure gas, providing the power for circulation. The condenser dissipates the heat from the high-pressure gas to the outside, condensing it into a high-pressure liquid. The expansion valve rapidly reduces the pressure of the refrigerant during throttling, turning the high-pressure liquid into low-temperature, low-pressure wet vapor. The evaporator allows the low-temperature, low-pressure liquid to absorb heat and evaporate, completing the refrigeration process. With these four components, a functional basic refrigeration system can be formed. In this embodiment, the refrigeration system for transportation also includes a regenerator 5, a gas-liquid separator 8, and a gas bypass valve 10. A first solenoid valve is provided between the evaporator 9 and the regenerator 5, a second solenoid valve 12 is provided between the compressor 1 and the condenser 3, a third solenoid valve 13 is provided between the compressor 1 and the gas-liquid separator 8, and a fourth solenoid valve is provided between the compressor 1 and the evaporator 9. The regenerator, also called an "economist" or "liquid-suction heat exchanger," is installed between the evaporator outlet and the compressor suction port, allowing the high-pressure liquid at the condenser outlet to exchange heat with it; that is, the low-temperature steam from the evaporator "pre-cools" the high-pressure liquid, and then the high-pressure liquid "preheats" the low-temperature steam, achieving two goals at once—both increasing the cooling capacity and preventing liquid slugging in the compressor. The regenerator 5 can be any one of a plate heat exchanger, a regenerator-type economizer, or a flash economizer.

[0027] The specific connection structure is as follows: the exhaust port of the refrigeration compressor 1 is connected to the inlet of the second solenoid valve 12, the inlet of the third solenoid valve 13, and the inlet of the fourth solenoid valve 14, respectively; the outlet of the second solenoid valve 12 is connected to the inlet of the condenser 3; the outlet of the third solenoid valve 13 is connected to the inlet 8-a of the gas-liquid separator head 8; the outlet of the fourth solenoid valve 14 is connected to the outlet of the evaporator 9; the outlet of the condenser 3 is connected to the lower shell-side inlet 5-Ⅰ of the regenerator 5; the upper shell-side inlet 5-Ⅲ of the regenerator 5 is connected to the outlet of the gas bypass valve 10 and the outlet of the first solenoid valve 11, respectively; the upper shell-side inlet of the regenerator 5... Outlet 5-II is connected to the inlet of expansion valve 7. The outlet of expansion valve 7 is connected to the inlet 8-a of gas-liquid separation type liquid separator 8. The liquid separation hole 8-e of gas-liquid separation type liquid separator 8 is connected to the inlet of evaporator 9. The gas separation hole 8-f of gas-liquid separation type liquid separator 8 is connected to the inlet of gas bypass valve 10. The outlet of evaporator 9 is connected to the inlet of first solenoid valve 11 and the outlet of fourth solenoid valve 14. The outlet of gas bypass valve 10 is connected to the outlet of first solenoid valve 11 and the upper shell-side inlet 5-III of regenerator 5. The upper shell-side outlet 5-Ⅳ of regenerator 5 is connected to the suction port of refrigeration compressor 1. Through the above structural design, this refrigeration system for transportation can not only achieve gas bypass through the gas-liquid separation type distributor, enabling refrigerated trucks to adapt to various extreme environmental requirements, but also perform hot gas bypass defrosting and reverse hot gas bypass defrosting. Among them, hot gas bypass defrosting utilizes the high-temperature and high-pressure refrigerant gas discharged from the compressor to directly enter the evaporator for defrosting; reverse hot gas bypass defrosting involves the high-temperature and high-pressure refrigerant gas discharged from the compressor entering the evaporator outlet and starting from the evaporator outlet to perform high-temperature defrosting of the frost layer in reverse, thereby achieving the purpose of efficient defrosting.

[0028] Example 2, as Figure 1 As shown, a refrigeration system for transportation is further optimized based on Embodiment 1. In this embodiment, the refrigeration system for transportation also includes an oil separator 2. The exhaust port of the refrigeration compressor 1 is connected to the inlet of the oil separator 2, and the outlet of the oil separator 2 is connected to the inlets of the second solenoid valve 12, the third solenoid valve 13, and the fourth solenoid valve 14, respectively. Furthermore, the refrigeration system for transportation also includes a liquid receiver 4. The outlet of the condenser 3 is connected to the inlet of the liquid receiver 4; the outlet of the liquid receiver 4 is connected to the lower shell-side inlet 5-Ⅰ of the regenerator 5. The oil separator is located between the compressor exhaust port and the condenser inlet, quickly separating the lubricating oil flushed out with the high-pressure exhaust and returning it to the compressor crankcase, ensuring efficient heat exchange between the condenser and evaporator while preventing oil shortage in the compressor.

[0029] like Figure 2As shown, in this embodiment, the gas-liquid separation type distributor head 8 includes a cylindrical gas collection chamber 8-d and a conical liquid collection chamber 8-b. A gas-liquid separation baffle 8-c is provided between the gas collection chamber 8-d and the liquid collection chamber 8-b. An inlet 8-a is provided on the liquid collection chamber 8-b, and a gas separation hole 8-f and a liquid separation hole 8-e are provided on the gas collection chamber 8-d. Specifically, the gas collection chamber 8-d has one gas separation hole 8-f and several liquid separation holes 8-e; the gas separation hole 8-f is located in the middle of the gas collection chamber 8-d and corresponds vertically to the gas-liquid separation baffle 8-c; the several liquid separation holes 8-e are evenly distributed on a circle centered on the gas separation hole 8-f. In this embodiment, the refrigerant is separated into gas and liquid by the gas-liquid separation baffle and stored in the liquid collection chamber and gas collection chamber of the distributor head, respectively. The gas is then bypassed to improve the dryness of the refrigerant. Through this distributor head structure, the dryness of the refrigerant can be improved and the distribution efficiency of the distributor head can be increased. By modifying the structure of the liquid distributor, the refrigerant can be rationally distributed to each evaporator, solving problems such as insufficient cooling capacity, reduced cooling efficiency, and underutilization of evaporator area in the refrigeration mode of refrigerated trucks. The gas bypass function of the gas-liquid separation type liquid distributor enables refrigerated trucks to adapt to various extreme environmental requirements, which is of great significance to the development of the refrigerated truck industry.

[0030] In this embodiment, the regenerator 5 is equipped with an internal coil 6. The inlet of the internal coil 6 is connected to the lower shell-side inlet 5-Ⅰ of the regenerator 5, and the outlet of the internal coil 6 is connected to the upper shell-side outlet 5-Ⅱ of the regenerator 5. In this embodiment, the regenerator 5 includes a shell, with the internal coil 6 embedded within it. The lower shell-side inlet 5-Ⅰ is located at the lower part of the shell, while the upper shell-side outlets 5-Ⅱ, 5-Ⅲ, and 5-Ⅳ are respectively located at the upper part of the shell. In this embodiment, the regenerator employs a shell-and-tube heat exchanger with no moving parts, relying on the system pressure difference for natural heat exchange, resulting in low maintenance costs.

[0031] In this embodiment, as a complete refrigeration system, an electronic expansion valve is preferred. The exhaust port of the refrigeration compressor 1 is connected to the inlet of the oil separator 2; the outlet of the oil separator 2 is connected to the inlets of the second solenoid valve 12, the third solenoid valve 13, and the fourth solenoid valve 14, respectively; the outlet of the second solenoid valve 12 is connected to the inlet of the condenser 3; the outlet of the third solenoid valve 13 is connected to the inlet 8-a of the gas-liquid separation type distributor; the outlet of the fourth solenoid valve 14 is connected to the outlet of the evaporator 9; the outlet of the condenser 3 is connected to the inlet of the liquid storage tank 4; the outlet of the liquid storage tank 4 is connected to the lower inlet 5-Ⅰ of the regenerator shell side; the internal coil 6 of the regenerator is connected to the upper outlet 5-Ⅱ of the regenerator shell side; the upper inlet 5-Ⅲ of the regenerator shell side is connected to the outlet of the gas bypass valve 10 and the first solenoid valve 11, respectively. The outlets are connected as follows: the upper outlet 5-II of the regenerator shell side is connected to the inlet of the expansion valve 7; the outlet of the expansion valve 7 is connected to the inlet 8-a of the gas-liquid separator head; the liquid separation hole 8-e of the gas-liquid separator head is connected to the inlet of the evaporator 9; the gas separation hole 8-f of the gas-liquid separator head is connected to the inlet of the gas bypass valve 10; the outlet of the evaporator 9 is connected to the inlet of the first solenoid valve 11 and the outlet of the fourth solenoid valve 14; the outlet of the gas bypass valve 10 is connected to the outlet of the first solenoid valve 11; the outlet of the gas bypass valve 10 and the outlet of the first solenoid valve 11 are connected to the upper inlet 5-III of the regenerator shell side; and the upper outlet 5-IV of the regenerator shell side is connected to the suction port of the refrigeration compressor 1.

[0032] In this embodiment, the refrigeration system can operate in the following three modes:

[0033] 1. Refrigeration system refrigeration working mode

[0034] like Figure 3The diagram shown is a flowchart of the refrigeration working mode of the refrigeration system of this utility model. At this time, the second solenoid valve 12, the electronic expansion valve 7, the gas bypass 10, and the first solenoid valve 11 are open, while the third solenoid valve 13 and the fourth solenoid valve 14 are closed. The system's workflow is as follows: High-temperature, high-pressure gaseous refrigerant discharged from compressor 1 enters the inlet of oil separator 2 through a pipeline. The refrigerant gas then enters the inlet of condenser 3 from the outlet of oil separator 2. The high-temperature, high-pressure gaseous refrigerant is condensed into saturated liquid refrigerant or subcooled liquid refrigerant in condenser 3. It then enters the inlet of liquid receiver 4 from the outlet of condenser 3, and from the outlet of liquid receiver 4, it enters the lower shell-side inlet 5-Ⅰ of the regenerator. From the lower shell-side inlet 5-Ⅰ of the regenerator, it enters the internal coil 6 to recool the saturated liquid refrigerant or subcooled liquid refrigerant. The subcooled liquid refrigerant enters the inlet of electronic expansion valve 6 from the outlet of internal coil 6 and the upper shell-side outlet 5-Ⅱ of the regenerator. After throttling and expansion in electronic expansion valve 7, the subcooled liquid refrigerant becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant. This low-temperature, low-pressure gas-liquid two-phase refrigerant enters the inlet 8-a of a gas-liquid separator after passing through the outlet of electronic expansion valve 7. After entering the gas-liquid separator 8, the gas-liquid mixture is separated... The liquid separation orifice 8-e of the liquid separator separates the liquid and directs it into the inlet of the evaporator 9. The liquid refrigerant evaporates in the evaporator 9 into saturated or superheated gaseous refrigerant. This gaseous or superheated refrigerant exits the evaporator 9 and enters the inlet of the first solenoid valve 11. The gaseous or superheated refrigerant exits from the outlet of the first solenoid valve 11. The low-temperature, low-pressure gaseous refrigerant exiting from the gas separation orifice 8-f of the liquid separator enters the inlet of the gas bypass valve 10. After the low-temperature, low-pressure gaseous refrigerant exits from the outlet of the gas bypass valve 10, it mixes with the saturated or superheated gaseous refrigerant exiting from the outlet of the first solenoid valve 11 and enters the upper shell-side inlet 5-Ⅲ of the regenerator. The mixed refrigerant gas is superheated by the internal coil 6 of the regenerator, and the low-temperature, low-pressure gaseous refrigerant enters the suction port of the compressor 1 from the upper shell-side outlet 5-Ⅳ of the regenerator. After being compressed by the compressor 1, the high-temperature, high-pressure gaseous refrigerant is discharged and the next cycle begins.

[0035] 2. Refrigeration system hot gas bypass defrosting mode

[0036] like Figure 4As shown in the flowchart of the defrosting working mode of the refrigeration system of this utility model, the third solenoid valve 13 and the first solenoid valve 11 are open, while the second solenoid valve 12, the gas bypass valve 10, and the fourth solenoid valve 14 are closed. The electronic expansion valve 7 is opened first and then closed. The working process of the system is as follows: First, the electronic expansion valve 7 is opened to allow the remaining heat in the high-temperature and high-pressure refrigerant in the condenser 3 to enter the evaporator 9 for pre-defrosting. Then, the electronic expansion valve 7 is closed. After pre-defrosting, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1 enters the inlet of the oil separator 2. After exiting the oil separator 2, the high-temperature and high-pressure gaseous refrigerant enters the inlet of the third solenoid valve 13. After exiting the third solenoid valve 13, the high-temperature and high-pressure gaseous refrigerant enters the inlet 8-a of the gas-liquid separation type distributor. The liquid separation port 8-e outlet enters the evaporator 9 inlet. The high-temperature and high-pressure gaseous refrigerant is defrosted in the evaporator 9. After defrosting, the high-temperature and high-pressure gaseous refrigerant becomes a gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant exits from the evaporator 9 outlet and enters the first solenoid valve 11 inlet. After exiting from the first solenoid valve 11 outlet, the gas-liquid two-phase refrigerant enters the upper shell-side inlet 5-Ⅲ of the regenerator. The liquid remains in the regenerator shell. The gaseous refrigerant enters the suction port of the compressor 1. After being compressed by the compressor 1, the high-temperature and high-pressure gaseous refrigerant is discharged, and the next cycle begins.

[0037] Hot gas bypass defrosting utilizes the high-temperature, high-pressure refrigerant gas discharged from the compressor to directly enter the evaporator for defrosting. This high-temperature, high-pressure refrigerant gas has a high heat content, which can quickly melt the frost layer on the evaporator surface; hot gas bypass defrosting can evenly transfer heat to all parts of the evaporator, including the evaporator fins and the inside of the pipes, and can remove the frost layer more thoroughly.

[0038] 3. Reverse hot gas bypass defrosting mode of the refrigeration system

[0039] like Figure 5The diagram shows the reverse hot gas bypass defrosting working mode of the refrigeration unit of this utility model. In this mode, the fourth solenoid valve 14 and the gas bypass valve 10 are open, while the first solenoid valve 11, the second solenoid valve 12, and the third solenoid valve 13 are closed. The electronic expansion valve 7 opens first and then closes. The system's workflow is as follows: First, the electronic expansion valve 6 is opened, allowing the remaining heat from the high-temperature, high-pressure refrigerant in the condenser 3 to enter the evaporator 9 for pre-defrosting. Then, the electronic expansion valve 7 is closed. After pre-defrosting, the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 1 enters the inlet of the oil separator 2. The high-temperature, high-pressure gaseous refrigerant exits from the oil separator 2 and enters the inlet of the third solenoid valve 13. The high-temperature, high-pressure gaseous refrigerant exits from the third solenoid valve 13 and enters the inlet of the evaporator 9. The high-temperature, high-pressure gaseous refrigerant undergoes defrosting in the evaporator 9. After defrosting in the evaporator, the refrigerant becomes a gas-liquid mixture. The gas-liquid two-phase refrigerant exits from the outlet of evaporator 9 and enters the liquid separation hole 8-e of the gas-liquid separator. The gas-liquid two-phase refrigerant enters the inlet of gas bypass valve 10 from the gas bypass hole 8-f of the gas-liquid separator. The gas-liquid two-phase refrigerant enters the upper inlet 5-Ⅲ on the shell side of the regenerator from the outlet of gas bypass valve 10. The liquid remains in the regenerator shell, and the gaseous refrigerant enters the suction port of compressor 1. After being compressed by compressor 1, the high-temperature and high-pressure gaseous refrigerant is discharged, and the next cycle begins.

[0040] Both reverse hot gas bypass defrosting and hot gas bypass defrosting utilize the high-temperature, high-pressure refrigerant gas discharged from the compressor to directly enter the evaporator for defrosting. However, in reverse hot gas bypass defrosting, the high-temperature, high-pressure refrigerant gas discharged from the compressor enters the evaporator outlet and starts to defrost the frost layer in reverse from the evaporator outlet, thereby achieving the purpose of efficient defrosting.

[0041] 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 refrigeration system for transportation, comprising a compressor (1), a condenser (3), an expansion valve (7), and an evaporator (9), characterized in that: It also includes a regenerator (5), a gas-liquid separation type liquid separator (8) and a gas bypass valve (10). A first solenoid valve is provided between the evaporator (9) and the regenerator (5), a second solenoid valve (12) is provided between the compressor (1) and the condenser (3), a third solenoid valve (13) is provided between the compressor (1) and the gas-liquid separation type liquid separator (8), and a fourth solenoid valve is provided between the compressor (1) and the evaporator (9). The exhaust port of the refrigeration compressor (1) is connected to the inlet of the second solenoid valve (12), the inlet of the third solenoid valve (13), and the inlet of the fourth solenoid valve (14), respectively. The outlet of the second solenoid valve (12) is connected to the inlet of the condenser (3). The outlet of the third solenoid valve (13) is connected to the inlet (8-a) of the gas-liquid separation type distributor (8). The outlet of the fourth solenoid valve (14) is connected to the outlet of the evaporator (9). The outlet of the condenser (3) is connected to the lower shell-side inlet (5-I) of the regenerator (5). The upper shell-side inlet (5-III) of the regenerator (5) is connected to the outlet of the gas bypass valve (10) and the outlet of the first solenoid valve (11), respectively. The upper shell-side outlet (5-II) of the regenerator (5) is connected to the outlet of the gas bypass valve (10) and the outlet of the first solenoid valve (11), respectively. The expansion valve (7) is connected to the inlet of the expansion valve (7), the outlet of the expansion valve (7) is connected to the inlet (8-a) of the gas-liquid separation type liquid separator (8), the liquid separation hole (8-e) of the gas-liquid separation type liquid separator (8) is connected to the inlet of the evaporator (9), and the gas separation hole (8-f) of the gas-liquid separation type liquid separator (8) is connected to the inlet of the gas bypass valve (10); the outlet of the evaporator (9) is connected to the inlet of the first solenoid valve (11) and the outlet of the fourth solenoid valve (14); the outlet of the gas bypass valve (10) is connected to the outlet of the first solenoid valve (11) and the upper shell-side inlet (5-Ⅲ) of the regenerator (5); the upper shell-side outlet (5-Ⅳ) of the regenerator (5) is connected to the suction port of the refrigeration compressor (1).

2. The refrigeration system for transportation according to claim 1, characterized in that: The gas-liquid separation type liquid separator (8) includes a cylindrical gas collection chamber (8-d) and a conical liquid collection chamber (8-b). A gas-liquid separation baffle (8-c) is provided between the gas collection chamber (8-d) and the liquid collection chamber (8-b). An inlet (8-a) is provided on the liquid collection chamber (8-b). A gas separation hole (8-f) and a liquid separation hole (8-e) are provided on the gas collection chamber (8-d).

3. The refrigeration system for transportation according to claim 2, characterized in that: The gas collection chamber (8-d) has a gas separation hole (8-f) and several liquid separation holes (8-e); the gas separation hole (8-f) is located in the middle of the gas collection chamber (8-d) and corresponds vertically to the gas-liquid separation baffle (8-c); the several liquid separation holes (8-e) are evenly distributed on a circle centered on the gas separation hole (8-f).

4. The refrigeration system for transportation according to any one of claims 1 to 3, characterized in that: The regenerator (5) is equipped with an internal coil (6). The inlet of the internal coil (6) is connected to the lower inlet (5-Ⅰ) on the shell side of the regenerator (5), and the outlet of the internal coil (6) is connected to the upper outlet (5-Ⅱ) on the shell side of the regenerator (5).

5. The refrigeration system for transportation according to claim 4, characterized in that: The regenerator (5) includes a shell, an internal coil (6) is embedded in the shell, the lower end inlet (5-Ⅰ) of the shell is located at the lower part of the shell, and the upper end outlet (5-Ⅱ), the upper end inlet (5-Ⅲ) and the upper end outlet (5-Ⅳ) of the shell are respectively located at the upper part of the shell.

6. The refrigeration system for transportation according to claim 1 or 5, characterized in that: It also includes a liquid storage tank (4), the outlet of the condenser (3) is connected to the inlet of the liquid storage tank (4); the outlet of the liquid storage tank (4) is connected to the lower shell-side inlet (5-Ⅰ) of the regenerator (5).

7. The refrigeration system for transportation according to claim 6, characterized in that: It also includes an oil separator (2), the exhaust port of the refrigeration compressor (1) is connected to the inlet of the oil separator (2), and the outlet of the oil separator (2) is connected to the inlet of the second solenoid valve (12), the inlet of the third solenoid valve (13), and the inlet of the fourth solenoid valve (14), respectively.

8. The refrigeration system for transportation according to claim 1, characterized in that: The regenerator (5) can be any one of a plate heat exchanger, a regenerator-type economizer, or a flash economizer.

9. The refrigeration system for transportation according to claim 1, characterized in that: The condenser (3) and the evaporator (9) are any one of the following: finned tube heat exchanger, stacked heat exchanger, and parallel flow heat exchanger.

10. The refrigeration system for transportation according to claim 1, characterized in that: The expansion valve (7) is any one of the following: manual expansion valve, flow-blocking expansion valve, float expansion valve, thermal expansion valve, and electronic expansion valve.

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