Dual-evaporator refrigeration system, refrigeration device, and control method therefor

Abstract

A dual-evaporator refrigeration system, a refrigeration device, and a control method therefor. In the dual-evaporator refrigeration system, an air discharge port of a dual-cylinder compressor communicates with three lines: a first line sequentially communicates with a condenser assembly and a hot flow channel of an enthalpy-increasing heat exchanger, a connecting line communicating with an outlet of the hot flow channel of the enthalpy-increasing heat exchanger being split into three branches: a first branch sequentially communicates with a cold flow channel of the enthalpy-increasing heat exchanger and an enthalpy-increasing port of the dual-cylinder compressor via a throttling valve set; a second branch sequentially communicates with a first evaporator assembly and a first air suction port of the dual-cylinder compressor via a first expansion valve; and a third branch sequentially communicates with a second evaporator assembly and a second air suction port of the dual-cylinder compressor via a second expansion valve; a second line communicates with the second branch via a first solenoid valve; and a third line communicates with the third branch via a second solenoid valve. The present invention can achieve independent refrigeration of two temperature zones, and achieve alternate defrosting of the two temperature zones without influencing each other, thus reducing temperature fluctuation in the two temperature zones.

Description

A dual-evaporator refrigeration system, refrigeration equipment and its control method

[0001] This application claims priority to Chinese Patent Application No. 202411997887.6, filed with the Chinese Patent Office on December 31, 2024, entitled "A Dual Evaporator Refrigeration System, Refrigeration Equipment and Control Method Thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of cold chain technology, and more specifically, to a dual-evaporator refrigeration system. Furthermore, this invention also relates to a refrigeration device including the aforementioned dual-evaporator refrigeration system, and a control method applied to the aforementioned dual-evaporator refrigeration system. Background Technology

[0003] A dual-evaporator refrigeration system has two evaporators, enabling independent temperature control in two temperature zones. For example, in a refrigeration and freezing system, one evaporator can be used in the freezing zone (i.e., the ultra-low temperature zone), while the other evaporator can be used in the refrigeration zone (i.e., the low temperature zone), allowing the freezing and refrigeration zones to independently regulate their temperatures without interference.

[0004] In the process of realizing this invention, the inventors discovered at least the following problems in the prior art:

[0005] 1. When there is a large temperature difference between the two indoor zones, the pressure difference between the two evaporators will affect the stable operation of the refrigeration system.

[0006] 2. The two evaporators are connected to the same compressor. If one evaporator stops running, it will affect the cooling operation of the other evaporator, making it difficult for the dual-temperature zone to operate independently.

[0007] 3. When the evaporator in one temperature zone is defrosting, the evaporator in another temperature zone also needs to be defrosted or the cooling system needs to be shut off, which leads to unstable temperature in the other temperature zone and increases defrosting energy consumption.

[0008] In conclusion, how to solve any of the above problems is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0009] In view of this, the purpose of the present invention is to provide a dual-evaporator refrigeration system that can achieve independent refrigeration in each of the two temperature zones, and can achieve both joint defrosting and independent defrosting in the two temperature zones, thereby stabilizing the temperature in the two temperature zones and reducing defrosting energy consumption.

[0010] Another object of the present invention is to provide a refrigeration device including the above-described dual evaporator refrigeration system, and to provide a control method applied to the above-described dual evaporator refrigeration system.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] A dual-evaporator refrigeration system includes a dual-cylinder compressor, a condenser assembly, an enthalpy-increasing heat exchanger, a first evaporator assembly for installation in a first temperature zone, and a second evaporator assembly for installation in a second temperature zone.

[0013] The exhaust port of the dual-cylinder compressor is connected to the exhaust pipeline, which is divided into three pipelines:

[0014] The first pipeline connects sequentially to the condenser assembly and the hot runner inlet of the enthalpy-increasing heat exchanger. The hot runner outlet of the enthalpy-increasing heat exchanger is connected to a connecting pipeline, which is divided into three branches: the first branch connects sequentially to the cold runner of the enthalpy-increasing heat exchanger and the enthalpy-increasing port of the dual-cylinder compressor via a throttling valve assembly; the second branch connects sequentially to the first evaporator assembly and the first suction port of the dual-cylinder compressor via a first expansion valve; and the third branch connects sequentially to the second evaporator assembly and the second suction port of the dual-cylinder compressor via a second expansion valve.

[0015] The second pipeline connects to the second branch located between the first expansion valve and the first evaporator assembly via the first solenoid valve;

[0016] The third pipeline connects to the third branch located between the second expansion valve and the second evaporator assembly via the second solenoid valve.

[0017] Optionally, it also includes a first indoor temperature sensor for installation in a first temperature zone and a second indoor temperature sensor for installation in a second temperature zone, wherein the first indoor temperature sensor, the second indoor temperature sensor, the throttle valve assembly, the first expansion valve, and the second expansion valve are all signal-connected to the control unit.

[0018] Optionally, it also includes a first coil temperature sensor disposed on the first evaporator assembly and a second coil temperature sensor disposed on the second evaporator assembly, wherein the first coil temperature sensor, the second coil temperature sensor, the first solenoid valve and the second solenoid valve are all signal-connected to the control unit.

[0019] Optionally, an auxiliary pipeline is connected between the first branch located between the first evaporator assembly and the first suction port and the second branch located between the second evaporator assembly and the second suction port, and the auxiliary pipeline is provided with a third solenoid valve that is signal-connected to the control unit.

[0020] Optionally, the exhaust pipe is equipped with an exhaust temperature sensor and an exhaust pressure sensor, both of which are signal-connected to the control unit;

[0021] And / or, the first branch located between the first evaporator assembly and the first intake port is provided with a first intake temperature sensor and a first intake pressure sensor, both of which are signal-connected to the control unit;

[0022] And / or, the second branch located between the second evaporator assembly and the second intake port is provided with a second intake temperature sensor and a second intake pressure sensor, both of which are signal-connected to the control unit.

[0023] Optionally, a drying filter is provided on the connecting pipe that communicates with the hot flow channel outlet of the enthalpy-enhancing heat exchanger.

[0024] Optionally, the throttling valve assembly includes a fourth solenoid valve and a thermostatic expansion valve, which are sequentially arranged on the first branch along the direction from the hot flow outlet of the enthalpy-increasing heat exchanger to its cold flow inlet.

[0025] Optionally, the condenser assembly includes a condenser and a condenser fan disposed on one side of the condenser;

[0026] And / or, the first evaporator assembly includes a first evaporator and a first evaporation fan disposed on one side of the first evaporator;

[0027] And / or, the second evaporator assembly includes a second evaporator and a second evaporation fan disposed on one side of the second evaporator.

[0028] A refrigeration device comprising the dual evaporator refrigeration system described in any one of the preceding claims.

[0029] A control method, applied to the dual-evaporator refrigeration system described in any one of the above claims, the control method comprising:

[0030] Obtain the indoor temperature of the second temperature zone and the indoor temperature of the first temperature zone;

[0031] When the indoor temperature in the second temperature zone is higher than the first set temperature, determine whether the first temperature zone should operate independently for cooling.

[0032] If so, open the second expansion valve and the second evaporator assembly until the indoor temperature in the second temperature zone is less than or equal to the first set temperature;

[0033] If not, then start the dual-cylinder compressor, condenser assembly, second expansion valve, and second evaporator assembly until the indoor temperature in the second temperature zone is less than or equal to the first set temperature;

[0034] When the indoor temperature in the first temperature zone is higher than the second set temperature, determine whether the second temperature zone should operate independently for cooling.

[0035] If so, open the first expansion valve and the first evaporator assembly until the indoor temperature in the first temperature zone is less than or equal to the second set temperature;

[0036] If not, then start the dual-cylinder compressor, condenser assembly, first expansion valve, and first evaporator assembly until the indoor temperature in the first temperature zone is less than or equal to the second set temperature.

[0037] Optionally, the control method further includes:

[0038] Obtain the coil temperature in the second temperature zone and the coil temperature in the first temperature zone;

[0039] When the temperature of the first temperature zone coil is greater than or equal to the third set temperature, determine whether the temperature of the second temperature zone coil is less than the fourth set temperature. If so, open the second solenoid valve and close the second expansion valve until the temperature of the low temperature zone coil is greater than or equal to the fourth set temperature.

[0040] When the temperature of the first temperature zone coil is lower than the third set temperature, the first solenoid valve is opened and the first expansion valve is closed.

[0041] Determine whether the temperature of the first temperature zone coil is greater than or equal to the third set temperature. If so, close the first solenoid valve and open the first expansion valve.

[0042] While performing the step of determining whether the temperature of the first temperature zone coil is greater than or equal to the third set temperature, it also determines whether the temperature of the second temperature zone coil is less than the fourth set temperature. If so, the second solenoid valve is opened and the condenser assembly, throttle valve group, and second expansion valve are closed.

[0043] Determine whether the temperature of the second temperature zone coil is greater than or equal to the fourth set temperature. If so, close the second solenoid valve and open the condenser assembly, throttle valve group, and second expansion valve.

[0044] While performing the step of determining whether the temperature of the second temperature zone coil is greater than or equal to the fourth set temperature, it also determines whether the temperature of the first temperature zone coil is greater than or equal to the third set temperature. If so, the first solenoid valve is closed and the condenser assembly, throttle valve assembly, and first expansion valve are opened.

[0045] As can be seen from the above, the first temperature zone can be used as the ultra-low temperature zone, and the second temperature zone can be used as the low temperature zone. When the dual-evaporator refrigeration system provided by the present invention operates in the dual-temperature zone common refrigeration mode, the exhaust port of the dual-cylinder compressor discharges high-temperature gaseous refrigerant. The high-temperature gaseous refrigerant flows into the first pipeline and passes through the hot runner of the condenser assembly and the enthalpy-increasing heat exchanger in sequence to cool down and form low-temperature liquid refrigerant. Part of the low-temperature liquid refrigerant flows into the first branch and flows into the cold runner of the enthalpy-increasing heat exchanger after being throttled by the throttling valve assembly. Then, it absorbs the heat of the refrigerant in the hot runner of the enthalpy-increasing heat exchanger and flows into the enthalpy-increasing port of the dual-cylinder compressor. Part of the low-temperature liquid refrigerant flows into the second branch and flows into the first evaporator assembly after being throttled by the first expansion valve. Then, it absorbs the heat of the air in the first temperature zone and flows into the first suction port of the dual-cylinder compressor. Part of the low-temperature liquid refrigerant flows into the third branch and flows into the second evaporator assembly after being throttled by the second expansion valve. Then, it absorbs the heat of the air in the second temperature zone and flows into the second suction port of the dual-cylinder compressor. Thus, the first and second temperature zones can be cooled simultaneously. If only the first temperature zone needs to be cooled independently, the second expansion valve can be closed. If only the second temperature zone needs to be cooled independently, the first expansion valve can be closed.

[0046] After the refrigeration system has been running for a period of time, if the first temperature zone needs defrosting, the second temperature zone will operate in refrigeration mode. At this time, the first expansion valve is closed, the first solenoid valve is open, and the dual-cylinder compressor discharges high-temperature gaseous refrigerant. Part of the high-temperature gaseous refrigerant flows into the first evaporator assembly through the second pipeline to release heat and defrost. The cooled gaseous refrigerant flows into the first suction port of the dual-cylinder compressor, thus achieving defrosting in the first temperature zone. In addition, another part of the high-temperature gaseous refrigerant flows into the first pipeline and passes through the hot runner of the condenser assembly and the enthalpy-increasing heat exchanger in sequence to cool down and form low-temperature liquid refrigerant. Part of the low-temperature liquid refrigerant flows into the first branch, passes through the throttling valve assembly, and flows into the cold runner of the enthalpy-increasing heat exchanger. Then, it absorbs the heat of the refrigerant in the hot runner of the enthalpy-increasing heat exchanger and flows into the enthalpy-increasing port of the dual-cylinder compressor. Another part of the low-temperature liquid refrigerant flows into the third branch, passes through the second expansion valve, and flows into the second evaporator assembly. Then, it absorbs the heat of the air in the second temperature zone and flows into the second suction port of the dual-cylinder compressor, thus achieving refrigeration in the second temperature zone.

[0047] If the second temperature zone requires defrosting, the first temperature zone operates in cooling mode. In this mode, the second expansion valve is closed, the second solenoid valve is open, and the dual-cylinder compressor discharges high-temperature gaseous refrigerant. Part of this high-temperature gaseous refrigerant flows through the third pipe into the second evaporator assembly to release heat and defrost. The cooled gaseous refrigerant then flows into the second suction port of the dual-cylinder compressor, thus achieving defrosting in the second temperature zone. Additionally, another portion of the high-temperature gaseous refrigerant flows into the first pipe, passing sequentially through the condenser assembly and the hot runner of the enthalpy-enhancing heat exchanger, where it is cooled to form low-temperature liquid refrigerant. Part of this low-temperature liquid refrigerant flows into the first branch, passes through the throttling valve assembly, and then flows into the cold runner of the enthalpy-enhancing heat exchanger. It then absorbs heat from the refrigerant in the hot runner of the enthalpy-enhancing heat exchanger and flows into the enthalpy-enhancing port of the dual-cylinder compressor. The other portion of the low-temperature liquid refrigerant flows into the second branch, passes through the first expansion valve, and then flows into the first evaporator assembly. It then absorbs heat from the air in the first temperature zone and flows into the first suction port of the dual-cylinder compressor, thus achieving cooling in the first temperature zone.

[0048] If both the second and first temperature zones require defrosting, the throttle valve assembly, the first expansion valve, and the second expansion valve are closed. The dual-cylinder compressor discharges high-temperature gaseous refrigerant. Part of the high-temperature gaseous refrigerant flows into the first evaporator assembly through the second pipeline to release heat and defrost. The cooled gaseous refrigerant flows into the first suction port of the dual-cylinder compressor, thus completing the defrosting operation in the first temperature zone. The other part of the high-temperature gaseous refrigerant flows into the second evaporator assembly through the third pipeline to release heat and defrost. The cooled gaseous refrigerant flows into the second suction port of the dual-cylinder compressor, thus completing the defrosting operation in the second temperature zone.

[0049] In summary, the present invention has at least the following beneficial effects:

[0050] 1. The dual-cylinder compressor receives the gaseous refrigerant discharged from the enthalpy-enhancing heat exchanger, which can reduce the compressor's work and thus reduce the compressor's energy consumption. This is beneficial for the stable operation of refrigeration systems with dual temperature zones and saves system energy consumption.

[0051] 2. Evaporator components in different temperature zones are equipped with expansion valves, which can control the pressure inside the evaporator by adjusting the refrigerant flow rate, thereby effectively ensuring the stable operation of the refrigeration system.

[0052] 3. The dual-temperature zones can achieve both joint cooling and independent cooling, enabling the refrigeration system to operate in various modes, which helps improve the user experience.

[0053] 4. Dual temperature zones can achieve simultaneous defrosting and independent defrosting. When one temperature zone is defrosting, the other temperature zone does not need to be shut down, which can effectively ensure that the other temperature zone maintains its temperature better and avoid temperature fluctuations in the other temperature zone caused by defrosting in one temperature zone. This can reduce defrosting energy consumption and improve the user experience. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0055] Figure 1 is a schematic diagram of a dual-evaporator refrigeration system provided by the present invention;

[0056] Figure 2 is a schematic diagram of a dual-evaporator refrigeration system in a combined refrigeration mode in the second and first temperature zones;

[0057] Figure 3 is a schematic diagram of the dual evaporator refrigeration system in the independent refrigeration mode of the second temperature zone;

[0058] Figure 4 is a schematic diagram of the dual evaporator refrigeration system in the independent refrigeration mode of the first temperature zone;

[0059] Figure 5 is a schematic diagram of a dual-evaporator refrigeration system in the defrosting mode of both the second and first temperature zones;

[0060] Figure 6 is a schematic diagram of a dual-evaporator refrigeration system in the first temperature zone defrosting-second temperature zone refrigeration mode;

[0061] Figure 7 is a schematic diagram of a dual-evaporator refrigeration system in the first temperature zone cooling-second temperature zone defrosting mode;

[0062] Figure 8 is a control logic diagram of the refrigeration mode of the dual evaporator refrigeration system;

[0063] Figure 9 is a control logic diagram for the defrosting mode of a dual-evaporator refrigeration system.

[0064] Reference numerals: 1-Twin-cylinder compressor; 2-Condenser fan; 3-Condenser; 4-Enthalpy-increasing heat exchanger; 5-Drier filter; 6-Fourth solenoid valve; 7-Thermal expansion valve; 8-First expansion valve; 9-First evaporator; 10-First evaporator fan; 11-First indoor temperature sensor; 12-First coil temperature sensor; 13-Second expansion valve; 14-Second evaporator; 15-Second evaporator fan; 16-Second indoor temperature sensor; 17-Second coil temperature sensor; 18-Third solenoid valve; 19-First solenoid valve; 20-Second solenoid valve; 21-Exhaust temperature sensor; 22-Exhaust pressure sensor; 23-First suction temperature sensor; 24-First suction pressure sensor; 25-Second suction temperature sensor; 26-Second suction pressure sensor; I-First pipeline; II-Second pipeline; III-Third pipeline; I-1-First branch; I-2-Second branch; I-3-Third branch. Detailed Implementation

[0065] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0066] The core of this invention is to provide a dual-evaporator refrigeration system that can achieve independent refrigeration in each of the two temperature zones, and can also achieve joint defrosting and independent defrosting in both temperature zones, thereby stabilizing the temperature in both temperature zones and reducing defrosting energy consumption.

[0067] Another core aspect of this invention is to provide a refrigeration device including the aforementioned dual-evaporator refrigeration system, and to provide a control method applied to the aforementioned dual-evaporator refrigeration system.

[0068] Referring to Figure 1, this invention provides a dual-evaporator refrigeration system, including a dual-cylinder compressor 1, a condenser assembly, an enthalpy-increasing heat exchanger 4, a first evaporator assembly for installation in a first temperature zone, and a second evaporator assembly for installation in a second temperature zone. For example, the first temperature zone may be an ultra-low temperature zone (or freezing zone), and the second temperature zone may be a low temperature zone (or refrigeration zone).

[0069] The exhaust port of the twin-cylinder compressor 1 is connected to the exhaust pipe, which can be divided into three pipes.

[0070] It should be noted that the twin-cylinder compressor 1 has an enthalpy-increasing port for introducing enthalpy-increasing gas to reduce the compressor's work output, thereby facilitating stable operation of the dual-temperature zone refrigeration system and saving system energy. Furthermore, the twin-cylinder compressor 1 has two independent cylinders, which can simultaneously compress the refrigerant, thus improving compressor efficiency and consequently enhancing the refrigeration efficiency of the refrigeration system. The specific structure of the twin-cylinder compressor 1 can be found in existing technologies, but it is not the focus of this invention and will not be described in detail here.

[0071] The first pipe I connects sequentially to the condenser assembly and the hot runner inlet of the enthalpy-enhancing heat exchanger 4. The hot runner outlet of the enthalpy-enhancing heat exchanger 4 is connected to a connecting pipe, which can be divided into three branches: the first branch I-1 connects sequentially to the cold runner of the enthalpy-enhancing heat exchanger 4 and the enthalpy-enhancing port of the twin-cylinder compressor 1 via a throttling valve assembly; the second branch I-2 connects sequentially to the first evaporator assembly and the first suction port of the twin-cylinder compressor 1 via the first expansion valve 8; and the third branch I-3 connects sequentially to the second evaporator assembly and the second suction port of the twin-cylinder compressor 1 via the second expansion valve 13. The second pipe II connects sequentially to the second branch I-2 located between the first expansion valve 8 and the first evaporator assembly via the first solenoid valve 19.

[0072] It should be noted that the condenser assembly cools and converts the high-temperature gaseous refrigerant into a liquid state to achieve a cooling effect. The enthalpy-increasing heat exchanger 4 includes adjacent hot and cold flow channels capable of exchanging heat with each other. These channels supply heat to the hot fluid and cold fluid respectively, achieving efficient heat exchange between them. For example, the enthalpy-increasing heat exchanger 4 can be a plate heat exchanger. The evaporator assembly evaporates and converts the low-temperature refrigerant (which can be a gas-liquid mixture) into a low-temperature gaseous refrigerant, cooling the indoor air and achieving a cooling effect. Therefore, the first evaporator assembly, installed in the first temperature zone, can achieve cooling in the first temperature zone, and the second evaporator assembly, installed in the second temperature zone, can achieve cooling in the second temperature zone. The throttling valve assembly, the first expansion valve 8, and the second expansion valve 13 all function as throttling valves, reducing pressure and allowing the liquid refrigerant to pass through them, becoming low-temperature, low-pressure wet vapor (or a gas-liquid mixture), absorbing heat and evaporating into a low-temperature, low-pressure gaseous refrigerant to achieve the desired effect.

[0073] The second pipeline II connects to the second branch I-2 located between the first expansion valve 8 and the first evaporator assembly via the first solenoid valve 19.

[0074] It should be noted that after the first temperature zone operates in cooling mode for a period of time, if the surface temperature of the first evaporator assembly is lower than the dew point temperature of the air, frost will form on the surface of the first evaporator assembly. Therefore, the high-temperature gaseous refrigerant discharged from the dual-cylinder compressor 1 can directly enter the first evaporator assembly through the second pipe II to release heat and defrost. The cooled gaseous refrigerant then flows back to the first suction port of the dual-cylinder compressor 1, thus achieving defrosting in the first temperature zone. The first solenoid valve 19 controls the on / off state of the second pipe II and is only activated during defrosting mode in the first temperature zone.

[0075] The third pipeline III connects to the third branch I-3 located between the second expansion valve 13 and the second evaporator assembly via the second solenoid valve 20.

[0076] It should be noted that after the second temperature zone operates in cooling mode for a period of time, if the surface temperature of the second evaporator assembly is lower than the dew point temperature of the air, frost will form on the surface of the second evaporator assembly. Therefore, the high-temperature gaseous refrigerant discharged from the twin-cylinder compressor 1 can directly enter the second evaporator assembly through the third pipe III to release heat and defrost. The cooled gaseous refrigerant then flows back to the second suction port of the twin-cylinder compressor 1, thus achieving defrosting in the second temperature zone. The second solenoid valve 20 controls the opening and closing of the third pipe III, and it only opens when the second temperature zone is in defrosting mode.

[0077] The aforementioned dual-evaporator refrigeration system has three refrigeration modes, including a combined refrigeration mode for the second and first temperature zones, an independent refrigeration mode for the second temperature zone, and an independent refrigeration mode for the first temperature zone.

[0078] Please refer to Figure 2 for the combined cooling mode of the second and first temperature zones: In this mode, both the first solenoid valve 19 and the second solenoid valve 20 are closed. The exhaust port of the dual-cylinder compressor 1 discharges high-temperature gaseous refrigerant. The high-temperature gaseous refrigerant flows into the first pipeline I, passes through the condenser assembly and the hot runner of the enthalpy-enhancing heat exchanger 4 in sequence, and is cooled to form low-temperature liquid refrigerant. Part of the low-temperature liquid refrigerant flows into the first branch I-1, passes through the throttling valve assembly, and flows into the cold runner of the enthalpy-enhancing heat exchanger 4. Then, it absorbs the heat of the refrigerant in the hot runner of the enthalpy-enhancing heat exchanger 4 and flows into the enthalpy-enhancing port of the dual-cylinder compressor 1. Part of the low-temperature liquid refrigerant flows into the second branch I-2, passes through the first expansion valve 8, and flows into the first evaporator assembly. Then, it absorbs the heat of the air in the first temperature zone and flows into the first suction port of the dual-cylinder compressor 1. Part of the low-temperature liquid refrigerant flows into the third branch I-3, passes through the second expansion valve 13, and flows into the second evaporator assembly. Then, it absorbs the heat of the air in the second temperature zone and flows into the second suction port of the dual-cylinder compressor 1.

[0079] Please refer to Figure 3. Independent cooling mode for the second temperature zone: Simply close the first expansion valve 8 based on the above-mentioned combined cooling mode of the second and first temperature zones.

[0080] Please refer to Figure 4. Independent cooling mode for the first temperature zone: Simply close the second expansion valve 13 based on the above-mentioned combined cooling mode for the second and first temperature zones.

[0081] The aforementioned dual-evaporator refrigeration system has three defrosting modes, including a combined defrosting mode for the second and first temperature zones, a defrosting mode for the first temperature zone followed by refrigeration for the second temperature zone, and a refrigeration mode for the first temperature zone followed by defrosting for the second temperature zone.

[0082] Please refer to Figure 5 for the joint defrosting mode of the second and first temperature zones: In this mode, close the throttle valve assembly, the first expansion valve 8, and the second expansion valve 13, and open the first solenoid valve 19 and the second solenoid valve 20. The dual-cylinder compressor 1 discharges high-temperature gaseous refrigerant. Part of the high-temperature gaseous refrigerant flows into the first evaporator assembly through the second pipeline II to release heat and defrost. The cooled gaseous refrigerant flows into the first suction port of the dual-cylinder compressor 1, thus achieving defrosting in the first temperature zone. The other part of the high-temperature gaseous refrigerant flows into the second evaporator assembly through the third pipeline III to release heat and defrost. The cooled gaseous refrigerant flows into the second suction port of the dual-cylinder compressor 1, thus achieving defrosting in the low-temperature zone.

[0083] Please refer to Figure 6. First temperature zone defrosting - second temperature zone cooling mode: At this time, the first expansion valve 8 is closed, and the first solenoid valve 19, the throttle valve group and the second expansion valve 13 are all open. The dual-cylinder compressor 1 discharges high-temperature gaseous refrigerant. Part of the high-temperature gaseous refrigerant flows into the first evaporator assembly through the second pipeline II to release heat and defrost. The cooled gaseous refrigerant flows into the first suction port of the dual-cylinder compressor 1, thus realizing the first temperature zone defrosting operation. In addition, another portion of the high-temperature gaseous refrigerant flows into the first pipeline I, passes through the condenser assembly and the hot runner of the enthalpy-increasing heat exchanger 4 in sequence, and is cooled to form a low-temperature liquid refrigerant. Part of the low-temperature liquid refrigerant flows into the first branch I-1, passes through the throttling valve assembly, and flows into the cold runner of the enthalpy-increasing heat exchanger 4. Then, it absorbs the heat of the refrigerant in the hot runner of the enthalpy-increasing heat exchanger 4 and flows into the enthalpy-increasing port of the twin-cylinder compressor 1. Another portion of the low-temperature liquid refrigerant flows into the third branch I-3, passes through the second expansion valve 13, and flows into the second evaporator assembly. Then, it absorbs the heat of the air in the second temperature zone and flows into the second suction port of the twin-cylinder compressor 1, thus realizing the second temperature zone cooling.

[0084] Please refer to Figure 7. First temperature zone cooling - second temperature zone defrosting mode: At this time, the second expansion valve 13 is closed, and the second solenoid valve 20, the throttle valve group and the first expansion valve 8 are all open. The dual-cylinder compressor 1 discharges high-temperature gaseous refrigerant. Part of the high-temperature gaseous refrigerant flows into the second evaporator assembly through the third pipeline III to release heat and defrost. The cooled gaseous refrigerant flows into the second suction port of the dual-cylinder compressor 1, thus realizing the second temperature zone defrosting operation. In addition, another portion of the high-temperature gaseous refrigerant flows into the first pipeline I, passes through the condenser assembly and the hot runner of the enthalpy-increasing heat exchanger 4 in sequence, and is cooled to form a low-temperature liquid refrigerant. Part of the low-temperature liquid refrigerant flows into the first branch I-1, passes through the throttling valve assembly, and flows into the cold runner of the enthalpy-increasing heat exchanger 4. Then, it absorbs the heat of the refrigerant in the hot runner of the enthalpy-increasing heat exchanger 4 and flows into the enthalpy-increasing port of the twin-cylinder compressor 1. Another portion of the low-temperature liquid refrigerant flows into the second branch I-2, passes through the first expansion valve 8, and flows into the first evaporator assembly. Then, it absorbs the heat of the air in the first temperature zone and flows into the first suction port of the twin-cylinder compressor 1, thus achieving cooling in the first temperature zone.

[0085] Therefore, the dual evaporator refrigeration system provided by the present invention can achieve independent refrigeration in each of the two temperature zones, and can also achieve independent defrosting of one temperature zone while the other temperature zone continues to refrigerate, so as to avoid defrosting or shutting off the refrigeration in the other temperature zone, thereby ensuring the temperature stability in the other temperature zone and saving defrosting energy consumption.

[0086] Regarding the specific configuration of the condenser assembly, based on the above embodiment, please refer to Figure 1. The condenser assembly includes a condenser 3 and a condensing fan 2 located on one side of the condenser 3.

[0087] The condenser fan 2 and the condenser 3 can both be installed on the outdoor side. The first pipeline I is connected in sequence to the hot flow inlet of the condenser 3 and the enthalpy heat exchanger 4. The condenser fan 2 can be set on the air inlet side or the air outlet side of the condenser 3. By rotating at high speed, it draws outdoor air into the condenser 3, takes away the heat generated by the refrigerant during the condensation process, and changes the refrigerant from a gaseous state to a liquid state, thereby achieving a cooling effect.

[0088] Regarding the specific configuration of the first evaporator assembly, based on the above embodiments, the first evaporator assembly includes a first evaporator 9 and a first evaporation fan 10 disposed on one side of the first evaporator 9.

[0089] The first evaporator fan 10 and the first evaporator 9 can both be installed in the first temperature zone. The second branch I-2 is connected to the first evaporator 9 and the first suction port of the dual-cylinder compressor 1 in sequence through the first expansion valve 8. The first evaporator fan 10 can be set on the air inlet side or the air outlet side of the first evaporator 9. The hot air in the first temperature zone is introduced into the first evaporator 9 by high-speed rotation. The hot air is released into the room after exchanging heat with the first evaporator 9, thereby achieving the cooling effect of the first temperature zone.

[0090] Regarding the specific configuration of the second evaporator assembly, based on the above embodiments, the second evaporator assembly includes a second evaporator 14 and a second evaporation fan 15 disposed on one side of the second evaporator 14.

[0091] The second evaporator fan 15 and the second evaporator 14 can both be installed in the second temperature zone. The third branch I-3 is connected to the second evaporator 14 and the second air intake of the twin-cylinder compressor 1 in sequence through the second expansion valve 13. The second evaporator fan 15 can be set on the air inlet side or the air outlet side of the second evaporator 14. By rotating at high speed, the hot air in the second temperature zone is introduced into the second evaporator 14. The hot air is released into the room after exchanging heat with the second evaporator 14, thereby achieving the cooling effect of the second temperature zone.

[0092] To achieve automated control of the refrigeration mode of the refrigeration system, based on the above embodiments and referring to Figure 1, the present invention also includes a first indoor temperature sensor 11 for installation in the first temperature zone and a second indoor temperature sensor 16 for installation in the second temperature zone. The first indoor temperature sensor 11, the second indoor temperature sensor 16, the throttle valve group, the first expansion valve 8, and the second expansion valve 13 are all signal connected to the control unit.

[0093] Specifically, the first indoor temperature sensor 11 is used to detect the indoor temperature of the first temperature zone in real time and transmit the signal to the control unit. The control unit can determine whether the first temperature zone needs to enter cooling mode based on the indoor temperature. If cooling mode is required, it controls the valve components required to activate the cooling mode of the first temperature zone, such as the first expansion valve 8 and the throttle valve assembly. Similarly, the second indoor temperature sensor 16 is used to detect the indoor temperature of the second temperature zone in real time and transmit the signal to the control unit. The control unit can determine whether the second temperature zone needs to enter cooling mode based on the indoor temperature. If cooling mode is required, it controls the valve components required to activate the cooling mode of the second temperature zone, such as the second expansion valve 13 and the throttle valve assembly. Therefore, by adopting the above configuration, the cooling mode of the refrigeration system can be automatically controlled, making the refrigeration system more intelligent and stable.

[0094] To achieve automated control of the defrosting mode of the refrigeration system, based on the above embodiments and referring to Figure 1, the present invention further includes a first coil temperature sensor 12 disposed on the first evaporator assembly and a second coil temperature sensor 17 disposed on the second evaporator assembly. The first coil temperature sensor 12, the second coil temperature sensor 17, the first solenoid valve 19 and the second solenoid valve 20 are all signal connected to the control unit.

[0095] Specifically, evaporator frosting typically occurs on the coils. A first coil temperature sensor 12 is installed on the coil of the first evaporator 9 to monitor the coil temperature (i.e., the first temperature zone coil temperature) in real time and transmit the signal to the control unit. The control unit can determine whether the first temperature zone needs to enter defrost mode based on the first temperature zone coil temperature. If defrost mode is required, it controls the opening and closing of the valves required for defrost mode in the first temperature zone, such as opening the first solenoid valve 19 and closing the first expansion valve 8. Similarly, a second coil temperature sensor 17 is installed on the coil of the second evaporator 14 to monitor the coil temperature (i.e., the second temperature zone coil temperature) in real time and transmit the signal to the control unit. The control unit can also determine whether the second temperature zone needs to enter defrost mode based on the second temperature zone coil temperature. If defrost mode is required, it controls the opening and closing of the valves required for defrost mode in the second temperature zone, such as opening the second solenoid valve 20 and closing the second expansion valve 13. Therefore, by adopting the above configuration, automated control of the defrost mode of the refrigeration system can be achieved, resulting in better intelligence and stability of the refrigeration system.

[0096] It should be noted that the dual-cylinder compressor 1 has two cylinders. In the independent cooling mode of the second temperature zone or the independent cooling mode of the first temperature zone, one cylinder draws in gas through its corresponding intake port to perform the compression action, while the other cylinder does not draw in gas to perform the compression action or is directly shut off. The other cylinder may experience frequent start-stop or internal pressure imbalance, which will shorten the service life of the compressor.

[0097] To effectively avoid the above situation and improve the service life of the compressor, based on the above embodiment, please refer to Figure 1. An auxiliary pipeline is connected between the first branch I-1 located between the first evaporator assembly and the first suction port and the second branch I-2 located between the second evaporator assembly and the second suction port. A third solenoid valve 18 connected to the control unit is provided on the auxiliary pipeline.

[0098] Therefore, in the independent cooling mode of the second temperature zone or the independent cooling mode of the first temperature zone, opening the third solenoid valve 18 allows both suction ports of the dual-cylinder compressor 1 to draw in gas, thereby enabling both cylinders of the dual-cylinder compressor 1 to draw in gas and perform compression actions in coordination, which helps improve the compressor's working efficiency and service life. It should be noted that in the combined cooling mode of the second and first temperature zones, the combined defrosting mode of the second and first temperature zones, the defrosting-cooling mode of the first temperature zone, and the cooling-defrosting mode of the first temperature zone, the third solenoid valve 18 remains closed, allowing the two suction ports of the dual-cylinder compressor 1 to correspondingly draw in the gaseous refrigerant discharged from both temperature zones, effectively ensuring that different temperature zones can operate independently in cooling or defrosting modes.

[0099] To ensure the safe and stable operation of the refrigeration system, based on the above embodiment, please refer to Figure 1. An exhaust temperature sensor 21 and an exhaust pressure sensor 22 are provided on the exhaust pipe connected to the exhaust port of the twin-cylinder compressor 1. Both of them are connected to the control unit.

[0100] Specifically, the exhaust temperature sensor 21 is used to detect the exhaust temperature of the twin-cylinder compressor 1 in real time and transmit the signal to the control unit. The control unit adjusts the operating state of the twin-cylinder compressor 1 according to the acquired exhaust temperature to ensure that the discharged gas is within a reasonable temperature range. The exhaust pressure sensor 22 is used to detect the exhaust pressure of the twin-cylinder compressor 1 in real time and transmit the signal to the control unit. The control unit adjusts the operating state of the twin-cylinder compressor 1 according to the acquired exhaust pressure to ensure that the exhaust gas pressure is within a reasonable pressure range. Therefore, the above settings ensure that the control system operates within a stable temperature and pressure range, thereby ensuring the safe and stable operation of the refrigeration system.

[0101] Further, referring to Figure 1, the first branch I-1 located between the first evaporator assembly and the first intake port is provided with a first intake temperature sensor 23 and a first intake pressure sensor 24, both of which are signal connected to the control unit, and / or, the second branch I-2 located between the second evaporator assembly and the second intake port is provided with a second intake temperature sensor 25 and a second intake pressure sensor 26, both of which are signal connected to the control unit.

[0102] Specifically, the first suction pressure sensor 24 is used to detect the suction pressure of the first suction port in real time and transmit the signal to the control unit. The second suction pressure sensor 26 is used to detect the suction pressure of the second suction port in real time and transmit the signal to the control unit. Since the suction pressure of both the first and second suction ports is related to the refrigerant flow rate, the suction pressure can reflect the cooling effect or defrosting effect within the temperature range. For example, if the suction pressure is too low, it indicates that there is insufficient refrigerant and the evaporator has a poor cooling or defrosting effect. The control unit can adjust the operating status of the dual-cylinder compressor 1 according to the suction pressure of the first and / or second suction ports, thereby ensuring the safe and stable operation of the refrigeration system.

[0103] Based on the above embodiments, please refer to Figure 1. A drying filter 5 is provided on the connecting pipe that is connected to the hot runner outlet of the enthalpy-enhancing heat exchanger 4.

[0104] Specifically, the dryer filter 5 mainly functions to filter impurities and absorb moisture. It can remove mechanical impurities from the refrigerant and prevent them from entering the evaporator in different temperature zones, thereby ensuring the safe and stable operation of the refrigeration system.

[0105] Regarding the specific configuration of the throttling valve assembly, based on the above embodiment, please refer to Figure 1. The throttling valve assembly includes a fourth solenoid valve 6 and a thermostatic expansion valve 7, which are sequentially arranged on the first branch I-1 along the direction from the hot flow outlet of the enthalpy-increasing heat exchanger 4 to its cold flow inlet.

[0106] Specifically, the thermal expansion valve 7 is installed on the first branch I-1. A portion of the refrigerant discharged from the hot flow channel of the enthalpy-enhancing heat exchanger 4 is throttled by the thermal expansion valve 7 into low-temperature, low-pressure wet vapor (or gas-liquid mixture), and then flows into the cold flow channel of the enthalpy-enhancing heat exchanger 4 to absorb heat and evaporate into low-temperature, low-pressure gaseous refrigerant. This low-temperature, low-pressure gaseous refrigerant flows into the dual-cylinder compressor 1 through the enthalpy-enhancing port, realizing the enthalpy-enhancing function. The thermal expansion valve 7 maintains a certain superheat to prevent liquid refrigerant from entering the dual-cylinder compressor 1 and causing liquid slugging. Because the thermal expansion valve 7 maintains a certain superheat, it cannot be completely closed. Therefore, a fourth solenoid valve 6 is installed on the first branch I-1, located before the thermal expansion valve 7, to control the opening and closing of the first branch I-1.

[0107] The present invention also provides a refrigeration device including the dual evaporator refrigeration system disclosed in the above embodiments. The refrigeration device is suitable for scenarios with a first temperature zone and a second temperature zone, such as refrigerators or refrigerated trucks, where the freezing zone is the first temperature zone and the refrigeration zone is the second temperature zone.

[0108] The present invention also provides a control method applied to the dual-evaporator refrigeration system disclosed in the above embodiments. Referring to Figure 8, the specific steps of the control method include:

[0109] S1: Obtain the indoor temperature of the second temperature zone (represented as the indoor temperature of the low temperature zone in the attached diagram, i.e., the second temperature zone can be the low temperature zone) and the indoor temperature of the first temperature zone (represented as the indoor temperature of the ultra-low temperature zone in the attached diagram, i.e., the first temperature zone can be the ultra-low temperature zone).

[0110] Specifically, the control unit receives a first set temperature Ta and a second set temperature Tb. The refrigeration system enters standby mode and uses the first indoor temperature sensor 11 to detect the indoor temperature T1 of the first temperature zone in real time and transmits it to the control unit. It also uses the second indoor temperature sensor 16 to detect the indoor temperature T2 of the second temperature zone in real time and transmits it to the control unit.

[0111] S2: Determine whether the indoor temperature T2 of the second temperature zone is greater than the first set temperature Ta;

[0112] S3: If not, return to step S1;

[0113] S4: If yes, then determine whether the first temperature zone is operating with independent cooling;

[0114] It should be noted that if T2>Ta, it means that the indoor temperature in the second temperature zone is too high and the cooling mode needs to be turned on. Before turning on the cooling mode in the second temperature zone, it is necessary to further determine whether the first temperature zone is running independent cooling.

[0115] S5: If the first temperature zone operates independently for cooling, then open the second expansion valve 13 and the second evaporator assembly until the indoor temperature T2 of the second temperature zone is less than or equal to the first set temperature Ta.

[0116] Specifically, if the first temperature zone operates with independent cooling, it means that the dual-cylinder compressor 1, condenser assembly (including condenser fan 2), throttle valve assembly (including fourth solenoid valve 6), first expansion valve 8, and first evaporator assembly (i.e., first evaporator fan 10) are all open. Directly opening the second expansion valve 13 and the second evaporator assembly (including second evaporator fan 15) will cool the second temperature zone. At this time, the system is in a combined cooling mode for both the second and first temperature zones. It should be noted that if the third solenoid valve 18 mentioned above is used, it must also be closed.

[0117] S6: After executing the above step S5, determine whether the indoor temperature T2 of the second temperature zone is less than or equal to the first set temperature Ta. If yes, close the second expansion valve 13 and the second evaporator assembly. If no, continue to execute the step of determining whether the indoor temperature T2 of the low temperature zone is less than the first set temperature Ta.

[0118] Specifically, after executing step S5 above, i.e., after achieving the combined cooling mode of the second and first temperature zones, if T2 ≤ Ta, it indicates that the indoor temperature of the second temperature zone meets the requirements. Closing the second expansion valve 13 and the second evaporator assembly (including the second evaporator fan 15) will end the cooling of the second temperature zone and allow the independent cooling mode of the first temperature zone to continue. It should be noted that if the third solenoid valve 18 described above is used, it is also necessary to open the third solenoid valve 18.

[0119] S7: If the first temperature zone does not operate independently for cooling, then start the dual-cylinder compressor 1, condenser assembly, second expansion valve 13, and second evaporator assembly until the indoor temperature T2 of the second temperature zone is less than or equal to the first set temperature Ta.

[0120] Specifically, this means that neither the second nor the first temperature zone is in cooling mode at this time. The dual-cylinder compressor 1, the condenser assembly (including the condenser fan 2), the throttle valve assembly (including the fourth solenoid valve 6), the second expansion valve 13, and the second evaporator assembly (including the second evaporator fan 15) are all off. To cool the second temperature zone, the dual-cylinder compressor 1, condenser fan 2, fourth solenoid valve 6, second expansion valve 13, and second evaporator fan 15 must be turned on. At this time, the system is in independent cooling mode for the second temperature zone. It should be noted that if the third solenoid valve 18 mentioned above is used, it must also be turned on.

[0121] S8: After executing step S7 above, determine whether the indoor temperature T2 of the second temperature zone is less than or equal to the first set temperature Ta. If T2>Ta, return to step S7; if T2≤Ta, determine whether the refrigeration system exits the refrigeration mode. If it exits the refrigeration mode, shut down the dual-cylinder compressor 1, condenser fan, fourth solenoid valve 6, second expansion valve 13, and second evaporator fan 15. If it does not exit the refrigeration mode, shut down the second expansion valve 13 and the second evaporator fan 15, and return to step S2.

[0122] Specifically, after executing step S7 above, that is, after the system starts the independent cooling mode of the second temperature zone, if T2≤Ta, it means that the indoor temperature of the second temperature zone meets the requirements. If an exit cooling mode command is obtained, all fans and valves are turned off and the cooling system exits the cooling mode. If no exit cooling mode command is obtained, the second expansion valve 13 and the second evaporator fan 15 are turned off, and the independent cooling mode of the second temperature zone ends.

[0123] S9: After performing the above step S1, determine whether the indoor temperature T1 of the first temperature zone is greater than the second set temperature Tb;

[0124] S10: If not, return to step S2;

[0125] S11: If yes, then determine whether the second temperature zone is operating with independent cooling;

[0126] It should be noted that if T1>Tb, it means that the indoor temperature in the first temperature zone is too high and the cooling mode needs to be turned on. Before turning on the cooling mode in the first temperature zone, it is necessary to further determine whether the second temperature zone is running independent cooling.

[0127] S12: If the second temperature zone operates independently for cooling, then open the first expansion valve 8 and the first evaporator assembly until the indoor temperature T1 of the first temperature zone is less than or equal to the second set temperature Tb.

[0128] Specifically, if the second temperature zone operates with independent cooling, it means that the dual-cylinder compressor 1, condenser assembly (including condenser fan 2), throttle valve assembly (including fourth solenoid valve 6), second expansion valve 13, and second evaporator assembly (including second evaporator fan 15) are all open. Directly opening the first expansion valve 8 and the first evaporator fan 10 in the first evaporator assembly will cool the first temperature zone. At this time, the system is in a combined cooling mode for both the first and second temperature zones. It should be noted that if the third solenoid valve 18 mentioned above is used, it must also be closed.

[0129] S13: After executing the above step S12, determine whether the indoor temperature T1 of the first temperature zone is less than or equal to the second set temperature Tb. If yes, close the second expansion valve 13 and the second evaporator assembly. If no, continue to execute the step of determining whether the indoor temperature T1 of the first temperature zone is less than or equal to the second set temperature Tb.

[0130] Specifically, after performing step S12 above, i.e., after achieving the combined cooling mode of the second and first temperature zones, if T1 ≤ Tb, it indicates that the indoor temperature of the first temperature zone meets the requirements. Closing the first expansion valve 8 and the first evaporator fan 10 will end the cooling of the first temperature zone and allow the independent cooling mode of the first temperature zone to continue. It should be noted that if the third solenoid valve 18 mentioned above is used, it is also necessary to open the third solenoid valve 18.

[0131] S14: If the second temperature zone does not operate independently for cooling, then start the dual-cylinder compressor 1, condenser assembly, first expansion valve 8, and first evaporator assembly until the indoor temperature T1 of the first temperature zone is less than or equal to the second set temperature Tb.

[0132] Specifically, this means that neither the second nor the first temperature zone is in cooling mode at this time. The dual-cylinder compressor 1, condenser fan 2, fourth solenoid valve 6, second expansion valve 13, and second evaporator fan 15 are all off. To cool the first temperature zone, the dual-cylinder compressor 1, condenser fan 2, fourth solenoid valve 6, second expansion valve 13, and second evaporator fan 15 must be turned on. At this point, the system is in independent cooling mode for the first temperature zone. It should be noted that if the third solenoid valve 18 mentioned above is used, it must also be turned on.

[0133] S15: After executing step S14 above, determine whether the indoor temperature T1 of the first temperature zone is less than or equal to the second set temperature Tb. If T1>Tb, return to step S14; if T1≤Tb, determine whether the refrigeration system exits the refrigeration mode. If it exits the refrigeration mode, turn off the dual-cylinder compressor, condenser fan, fourth solenoid valve 6, first expansion valve 8, and first evaporator fan 10. If it does not exit the refrigeration mode, turn off the first expansion valve 8 and the first evaporator fan 10, and return to step S2.

[0134] Specifically, after executing step S14 above, that is, after the system starts the independent cooling mode of the first temperature zone, if T1≤Tb, it means that the indoor temperature of the first temperature zone meets the requirements. If an exit cooling mode command is obtained, all fans and valves are turned off and the cooling system exits the cooling mode. If no exit cooling mode command is obtained, the first expansion valve 8 and the first evaporator fan 10 are turned off, and the independent cooling mode of the first temperature zone ends.

[0135] Therefore, the above control method can realize the synchronous cooling mode of the second temperature zone and the first temperature zone, the independent cooling mode of the second temperature zone, and the independent cooling mode of the first temperature zone, which expands the cooling conditions of the cooling system and helps to improve the user experience.

[0136] Please refer to Figure 9. The control method provided by this invention also includes the following specific steps.

[0137] S1′: Obtain the coil temperature of the second temperature zone (represented as the low temperature zone coil temperature in the attached figure, that is, the second temperature zone can be the low temperature zone) and the coil temperature of the first temperature zone (represented as the ultra-low temperature zone coil temperature in the attached figure, that is, the first temperature zone can be the ultra-low temperature zone).

[0138] Specifically, regardless of whether the second temperature zone and the first temperature zone are operating simultaneously or in cooling mode, the control unit will input the third set temperature Tc and the fourth set temperature Td in advance. The first coil temperature sensor 12 is used to detect the coil temperature T3 of the first temperature zone in real time and transmit it to the control unit. The second coil temperature sensor 17 is used to detect the coil temperature T4 of the low temperature zone in real time.

[0139] S2′: Determine whether the temperature of the coil in the first temperature zone is lower than the third set temperature;

[0140] S3′: If the coil temperature in the first temperature zone is greater than or equal to the third set temperature, determine whether the coil temperature in the second temperature zone is less than the fourth set temperature.

[0141] It should be noted that if T3≥Tc, it means that defrosting is not required in the first temperature zone, and we continue to determine whether the coil temperature in the low temperature zone is lower than the fourth set temperature.

[0142] S4': If the temperature of the coil in the second temperature zone is greater than or equal to the fourth set temperature, return to step S1;

[0143] It should be noted that if T4≥Td, it means that defrosting is not required in the second temperature zone, and return to step S1' to execute the next round of control.

[0144] S5': If the temperature of the coil in the second temperature zone is less than the fourth set temperature, open the second solenoid valve 20 and close the second expansion valve 13 until the temperature T4 of the coil in the second temperature zone is greater than or equal to the fourth set temperature Td;

[0145] Specifically, if T4<Td, it means that defrosting is required in the second temperature zone. At this time, during the operation of the refrigeration system, directly open the second solenoid valve 20, close the second expansion valve 13 and the second evaporation fan 15, that is, operate the defrosting mode for the second temperature zone - the refrigeration mode for the first temperature zone.

[0146] S6': After performing the above step S5', determine whether the temperature of the coil in the second temperature zone is greater than or equal to the fourth set temperature. If so, close the second solenoid valve and open the second expansion valve. If not, continue to execute step S5'.

[0147] Specifically, during the operation of the defrosting mode for the low temperature zone - the refrigeration mode for the first temperature zone, if T4≥Td, it means that defrosting of the low temperature zone needs to be ended. Close the second solenoid valve 20, open the second expansion valve 13 and the second evaporation fan 15, and the low temperature zone can be changed from the defrosting mode to the refrigeration mode and return to step S1'; if T4<Td, it means that defrosting of the low temperature zone is still required, and continue to operate the defrosting mode for the low temperature zone - the refrigeration mode for the first temperature zone.

[0148] S7': After performing the above step S2', if the temperature of the coil in the first temperature zone is less than the third set temperature, open the first solenoid valve 19 and close the first expansion valve 8;

[0149] Specifically, if T3<Tc, it means that defrosting is required in the first temperature zone. At this time, during the operation of the refrigeration system, directly open the first solenoid valve 19, close the first expansion valve 8 and the first evaporation fan 10 to defrost the first temperature zone, that is, operate the refrigeration mode for the second temperature zone - the defrosting mode for the first temperature zone.

[0150] S8': After performing the above step S7', determine whether the temperature of the coil in the first temperature zone is greater than or equal to the third set temperature. If so, close the first solenoid valve and open the first expansion valve. If not, continue to execute step S7';

[0151] Specifically, during the operation of the second-temperature-zone refrigeration - first-temperature-zone defrosting mode, if T3 ≥ Tc, it indicates that the defrosting of the first temperature zone needs to end. Close the first solenoid valve 19, open the first expansion valve 8 and the first evaporation fan 10, and the first temperature zone can enter the refrigeration mode from the defrosting mode and return to step S2′. If T3 < Tc, it indicates that the first temperature zone still needs to be defrosted, and continue to operate the second-temperature-zone refrigeration - first-temperature-zone defrosting mode.

[0152] S9′: After performing the above step S7′, it is also necessary to determine whether the coil temperature of the second temperature zone is less than the fourth set temperature.

[0153] It should be noted that during the operation of the second-temperature-zone refrigeration - first-temperature-zone defrosting mode, there is also a situation where the second evaporator 14 in the second temperature zone frosts. In addition, step S9 and step S8 are executed synchronously.

[0154] S10′: If the coil temperature of the second temperature zone is greater than or equal to the fourth set temperature, then execute the above step S8′.

[0155] It should be noted that during the operation of the second-temperature-zone refrigeration - first-temperature-zone defrosting mode, if T4 ≥ Td, it indicates that the second temperature zone does not need to be defrosted, and execute step S8′ to determine whether the defrosting mode of the first temperature zone ends.

[0156] S11′: If the coil temperature of the second temperature zone is less than the fourth set temperature, then open the second solenoid valve and close the condenser assembly, throttle valve group, and second expansion valve.

[0157] Specifically, during the operation of the second-temperature-zone refrigeration - first-temperature-zone defrosting mode, if T4 < Td, it indicates that the second temperature zone needs to be defrosted. Open the second solenoid valve 20, close the condenser fan 2, the fourth solenoid valve 6, the second expansion valve 13, and the second evaporation fan 15, and the synchronous defrosting mode of the second temperature zone and the first temperature zone can be operated.

[0158] S12′: Determine whether the coil temperature of the second temperature zone is greater than or equal to the fourth set temperature. If so, close the second solenoid valve 20 and open the condenser assembly (the condenser fan 2 therein), throttle valve group, and second expansion valve 13. If not, continue to execute the above step S11′.

[0159] Specifically, during the operation of the synchronous defrosting mode of the second temperature zone and the first temperature zone, if T4 ≥ Td, it indicates that the defrosting of the second temperature zone needs to end. Close the second solenoid valve 20, open the condenser fan 2, the fourth solenoid valve 6, the second expansion valve 13, and the second evaporation fan 15, and the defrosting mode of the second temperature zone can be converted to the refrigeration mode and return to step S8′. If T4 < Td, it indicates that the second temperature zone still needs to be defrosted, and continue to maintain the defrosting mode of the low-temperature zone.

[0160] S13': After performing the above step S11', it is also necessary to determine whether the temperature of the first temperature zone coil is greater than or equal to the third set temperature. If so, close the first solenoid valve 19 and open the condenser assembly, throttle valve group, and first expansion valve 8; if not, perform the above step S11'.

[0161] Specifically, during the operation of the synchronous defrosting mode of the second temperature zone and the first temperature zone, if T3≥Tc, it means that it is necessary to end the defrosting of the first temperature zone. Close the first solenoid valve 19 and open the condenser fan 2, fourth solenoid valve 6, first expansion valve 8, and first evaporation fan 10, that is, convert the defrosting mode of the first temperature zone into the refrigeration mode, and return to step S2'. If T3<Tc, it means that the first temperature zone still needs defrosting, and continue to maintain the defrosting mode of the first temperature zone. It should be noted that steps S12' and S13' need to be executed synchronously.

[0162] Therefore, the above control method can implement the synchronous defrosting mode of the second temperature zone and the first temperature zone, the refrigeration of the second temperature zone - defrosting of the first temperature zone mode, and the defrosting of the second temperature zone - refrigeration of the first temperature zone mode, realizing the cyclic defrosting of the two evaporators without mutual influence, and reducing the temperature fluctuation in the dual temperature zone.

[0163] It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0164] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0165] The above has introduced in detail a dual-evaporator refrigeration system, refrigeration equipment, and its control method provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A dual-evaporator refrigeration system, characterized in that, It includes a twin-cylinder compressor (1), a condenser assembly, an enthalpy-enhancing heat exchanger (4), a first evaporator assembly for installation in a first temperature zone, and a second evaporator assembly for installation in a second temperature zone; The exhaust port of the twin-cylinder compressor (1) is connected to the exhaust pipe, which is divided into three pipes: The first pipeline (I) is sequentially connected to the condenser assembly and the hot runner inlet of the enthalpy-enhancing heat exchanger (4). The hot runner outlet of the enthalpy-enhancing heat exchanger (4) is connected to the connecting pipeline. The connecting pipeline is divided into three branches: the first branch (I-1) is sequentially connected to the cold runner of the enthalpy-enhancing heat exchanger (4) and the enthalpy-enhancing port of the twin-cylinder compressor (1) via a throttling valve group; the second branch (I-2) is sequentially connected to the first evaporator assembly and the first suction port of the twin-cylinder compressor (1) via a first expansion valve (8); and the third branch (I-3) is sequentially connected to the second evaporator assembly and the second suction port of the twin-cylinder compressor (1) via a second expansion valve (13). The second pipeline (II) is connected via the first solenoid valve (19) to the second branch (I-2) located between the first expansion valve (8) and the first evaporator assembly; The third pipeline (III) is connected via the second solenoid valve (20) to the third branch (I-3) located between the second expansion valve (13) and the second evaporator assembly.

2. The dual-evaporator refrigeration system according to claim 1, characterized in that, It also includes a first indoor temperature sensor (11) for installation in the first temperature zone and a second indoor temperature sensor (16) for installation in the second temperature zone. The first indoor temperature sensor (11), the second indoor temperature sensor (16), the throttle valve assembly, the first expansion valve (8), and the second expansion valve (13) are all signal-connected to the control unit.

3. The dual-evaporator refrigeration system according to claim 1, characterized in that, It also includes a first coil temperature sensor (12) disposed on the first evaporator assembly and a second coil temperature sensor (17) disposed on the second evaporator assembly. The first coil temperature sensor (12), the second coil temperature sensor (17), the first solenoid valve (19) and the second solenoid valve (20) are all signal connected to the control unit.

4. The dual-evaporator refrigeration system according to claim 1, characterized in that, An auxiliary pipeline is connected between the first branch (I-1) located between the first evaporator assembly and the first suction port and the second branch (I-2) located between the second evaporator assembly and the second suction port. The auxiliary pipeline is equipped with a third solenoid valve (18) that is signal-connected to the control unit.

5. The dual-evaporator refrigeration system according to claim 1, characterized in that, The exhaust pipe is equipped with an exhaust temperature sensor (21) and an exhaust pressure sensor (22), both of which are signal-connected to the control unit; And / or, the first branch (I-1) located between the first evaporator assembly and the first intake port is provided with a first intake temperature sensor (23) and a first intake pressure sensor (24), both of which are signal connected to the control unit; And / or, the second branch (I-2) located between the second evaporator assembly and the second intake port is provided with a second intake temperature sensor (25) and a second intake pressure sensor (26), both of which are signal connected to the control unit.

6. The dual-evaporator refrigeration system according to claim 1, characterized in that, A drying filter (5) is provided on the connecting pipe that is connected to the hot flow channel outlet of the enthalpy-increasing heat exchanger (4).

7. The dual-evaporator refrigeration system according to claim 1, characterized in that, The throttling valve assembly includes a fourth solenoid valve (6) and a thermal expansion valve (7), which are sequentially arranged on the first branch (I-1) along the direction from the hot flow outlet of the enthalpy-increasing heat exchanger (4) to its cold flow inlet.

8. The dual-evaporator refrigeration system according to any one of claims 1 to 7, characterized in that, The condenser assembly includes a condenser (3) and a condenser fan (2) disposed on one side of the condenser (3); And / or, the first evaporator assembly includes a first evaporator (9) and a first evaporation fan (10) disposed on one side of the first evaporator (9); And / or, the second evaporator assembly includes a second evaporator (14) and a second evaporation fan (15) disposed on one side of the second evaporator (14).

9. A refrigeration device, characterized in that, The dual evaporator refrigeration system as described in any one of claims 1 to 8.

10. A control method, characterized in that, The control method, applied to the dual-evaporator refrigeration system according to any one of claims 1 to 8, comprises: Obtain the indoor temperature of the second temperature zone and the indoor temperature of the first temperature zone; When the indoor temperature in the second temperature zone is higher than the first set temperature, determine whether the first temperature zone should operate independently for cooling. If so, open the second expansion valve and the second evaporator assembly until the indoor temperature in the second temperature zone is less than or equal to the first set temperature; If not, then start the dual-cylinder compressor, condenser assembly, second expansion valve, and second evaporator assembly until the indoor temperature in the second temperature zone is less than or equal to the first set temperature; When the indoor temperature in the first temperature zone is higher than the second set temperature, determine whether the second temperature zone should operate independently for cooling. If so, open the first expansion valve and the first evaporator assembly until the indoor temperature in the first temperature zone is less than or equal to the second set temperature; If not, then start the dual-cylinder compressor, condenser assembly, first expansion valve, and first evaporator assembly until the indoor temperature in the first temperature zone is less than or equal to the second set temperature.

11. The control method according to claim 10, characterized in that, The control method further includes: Obtain the coil temperature in the second temperature zone and the coil temperature in the first temperature zone; When the temperature of the first temperature zone coil is greater than or equal to the third set temperature, determine whether the temperature of the second temperature zone coil is less than the fourth set temperature. If so, open the second solenoid valve and close the second expansion valve until the temperature of the second temperature zone coil is greater than or equal to the fourth set temperature. When the temperature of the first temperature zone coil is lower than the third set temperature, the first solenoid valve is opened and the first expansion valve is closed. Determine whether the temperature of the first temperature zone coil is greater than or equal to the third set temperature. If so, close the first solenoid valve and open the first expansion valve. While performing the step of determining whether the temperature of the first temperature zone coil is greater than or equal to the third set temperature, it also determines whether the temperature of the second temperature zone coil is less than the fourth set temperature. If so, the second solenoid valve is opened and the condenser assembly, throttle valve group, and second expansion valve are closed. Determine whether the temperature of the second temperature zone coil is greater than or equal to the fourth set temperature. If so, close the second solenoid valve and open the condenser assembly, throttle valve group, and second expansion valve. While performing the step of determining whether the temperature of the second temperature zone coil is greater than or equal to the fourth set temperature, it also determines whether the temperature of the first temperature zone coil is greater than or equal to the third set temperature. If so, the first solenoid valve is closed and the condenser assembly, throttle valve assembly, and first expansion valve are opened.

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