Double-evaporator refrigerating system, refrigerating equipment and control method thereof

Abstract

The invention discloses a double-evaporator refrigerating system, refrigerating equipment and a control method thereof.According to the double-evaporator refrigerating system, an exhaust port of a double-cylinder compressor communicates with one port of a four-way valve, and a four-way port of the four-way valve communicates with a condenser assembly and a hot runner inlet of an enthalpy-increasing heat exchanger in sequence; a connecting pipeline communicated with a hot runner outlet of the enthalpy-increasing heat exchanger is divided into three branches. The first branch is sequentially communicated with a cold runner of the enthalpy-increasing heat exchanger and an enthalpy-increasing opening of the double-cylinder compressor through a throttling valve set. The second branch is sequentially communicated with a first evaporator assembly and a two-way port of a four-way valve through a first expansion valve, and a three-way port of the four-way valve is communicated with a first air suction port of the double-cylinder compressor; and the third branch is sequentially communicated with the second evaporator assembly and a second air suction port of the double-cylinder compressor through a second expansion valve. Temperature rise of the second temperature area caused by defrosting of the first temperature area can be avoided, frequent starting and stopping of the system are reduced, heat released in the compression process can be recycled, energy consumption is reduced, and the stability and reliability of the system are improved.

Description

Technical Field

[0001] The present invention relates to the field of cold chain technology, and more specifically, to a dual-evaporator refrigeration system. In addition, the present invention also relates to a refrigeration device including the dual-evaporator refrigeration system, and a control method applied to the dual-evaporator refrigeration system. Background Art

[0002] The dual evaporator refrigeration system uses two evaporators in one refrigeration system to achieve independent temperature control in different areas. For example, in a refrigeration and freezing equipment, one evaporator can be used in the freezing area (i.e., ultra-low temperature area), while the other evaporator can be used in the refrigeration area (i.e., low temperature area), so that the freezing area and the refrigeration area can independently control the temperature without interfering with each other.

[0003] In the process of implementing the invention of this application, the inventors found that there are at least the following problems in the prior art:

[0004] 1. When one compressor is connected to two evaporators, the compressor will have insufficient power and cooling capacity, which will affect the stability of the system and cause high energy consumption.

[0005] 2. When a heat pump is used to defrost the ultra-low temperature zone, the temperature of the low temperature zone will rise. In order to maintain the set low temperature, the system needs to run more frequently, which also increases energy consumption.

[0006] In summary, how to solve any of the above problems is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0007] In view of this, an object of the present invention is to provide a dual-evaporator refrigeration system, which can reduce energy consumption and improve the stability and reliability of system operation.

[0008] Another object of the present invention is to provide a refrigeration device including the above-mentioned dual-evaporator refrigeration system, and also to provide a control method applied to the above-mentioned dual-evaporator refrigeration system.

[0009] In order to achieve the above object, the present invention provides the following technical solutions:

[0010] A dual-evaporator refrigeration system includes a dual-cylinder compressor, a four-way valve, 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;

[0011] The exhaust port of the two-cylinder compressor is connected to one port of the four-way valve, and the four-way port of the four-way valve is connected to the condenser assembly and the hot runner inlet of the enthalpy-increasing heat exchanger in sequence. The hot runner outlet of the enthalpy-increasing heat exchanger is connected to the connecting pipeline, and the connecting pipeline is divided into three branches:

[0012] The first branch is connected to the cold flow channel of the enthalpy-increasing heat exchanger and the enthalpy-increasing port of the dual-cylinder compressor in sequence through the throttle valve group;

[0013] The second branch is connected to the first evaporator assembly and the second port of the four-way valve in sequence through the first expansion valve, and the three-way port of the four-way valve is connected to the first suction port of the two-cylinder compressor;

[0014] The third branch is connected to the second evaporator assembly and the second suction port of the two-cylinder compressor in sequence through the second expansion valve.

[0015] Optionally, it also includes a first indoor temperature sensor for installation in the first temperature zone and a second indoor temperature sensor for installation in the second temperature zone, and the first indoor temperature sensor, the second indoor temperature sensor, the four-way valve, the throttling valve group, the first expansion valve, and the second expansion valve are all signal-connected to the control unit.

[0016] Optionally, it further includes a first coil temperature sensor provided in the first evaporator component and a second coil temperature sensor provided in the second evaporator component, and the signals of the first coil temperature sensor and the second coil temperature sensor are both connected to the control unit.

[0017] Optionally, the pipeline connecting the three-way port of the four-way valve and the first air intake port is connected to the third pipeline located between the second evaporator assembly and the second air intake port by an auxiliary pipeline, and a first solenoid valve connected to a control unit signal is provided on the auxiliary pipeline.

[0018] Optionally, the throttling valve group includes a second solenoid valve and a thermal expansion valve, which are sequentially arranged on the first branch along the direction from the hot runner outlet to the cold runner inlet of the enthalpy increase heat exchanger.

[0019] Optionally, a drying filter is provided on the connecting pipeline communicating with the hot runner outlet of the enthalpy-increasing heat exchanger.

[0020] Optionally, the condenser assembly includes a condenser and a condensing fan disposed on one side of the condenser;

[0021] And / or, the first evaporator assembly includes a first evaporator and a first evaporation fan disposed on one side of the first evaporator;

[0022] And / or, the second evaporator assembly includes a second evaporator and a second evaporation fan arranged on one side of the second evaporator.

[0023] A refrigeration device comprises the double evaporator refrigeration system described in any one of the above items.

[0024] A control method is applied to any of the above dual-evaporator refrigeration systems, the control method comprising:

[0025] Turning on the first evaporator assembly and the second evaporator assembly;

[0026] Obtaining the indoor temperature of the second temperature zone and the indoor temperature of the first temperature zone;

[0027] When the indoor temperature of the second temperature zone is greater than the second set temperature, it is determined whether the first temperature zone is in single-open cooling operation;

[0028] If yes, open the second expansion valve until the indoor temperature in the second temperature zone is less than or equal to the second set temperature;

[0029] If not, the dual-cylinder compressor, the condenser assembly, the throttle valve assembly, and the second expansion valve are turned on until the indoor temperature in the second temperature zone is less than or equal to the second set temperature;

[0030] When the indoor temperature of the first temperature zone is greater than the first set temperature, it is determined whether the second temperature zone is in single-open cooling operation;

[0031] If yes, open the first expansion valve until the indoor temperature in the first temperature zone is less than or equal to the first set temperature;

[0032] If not, the dual-cylinder compressor, the condenser assembly, the throttle valve assembly, and the first expansion valve are turned on until the indoor temperature in the first temperature zone is less than or equal to the first set temperature.

[0033] Optionally, the control method further includes:

[0034] Get the coil temperature of the first temperature zone;

[0035] When the temperature of the coil in the first temperature zone is lower than the third set temperature, the first port of the four-way valve and its second port are connected, the four-way port of the four-way valve and its three-way port are connected, the throttling valve group and the second expansion valve are closed, and the defrosting operation is performed for a period of time;

[0036] Determine whether the coil temperature in the first temperature zone is greater than or equal to the third set temperature, or determine whether the defrost time is greater than the preset defrost time;

[0037] If so, connect one port of the four-way valve with its four-way port, connect the two port of the four-way valve with its three-way port, and open the throttling valve group and the second expansion valve.

[0038] As can be seen from the above, the first temperature zone can be used as an ultra-low temperature zone, and the second temperature zone can be used as a low temperature zone. The dual evaporator refrigeration system provided by the present invention can operate in the following working modes:

[0039] Second temperature zone-first temperature zone co-opening refrigeration mode: the exhaust port of the twin-cylinder compressor discharges high-temperature gaseous refrigerant, and the high-temperature gaseous refrigerant enters the condenser assembly after passing through the four-way valve, and enters the hot runner of the enthalpy-increasing heat exchanger for heat exchange to form a low-temperature liquid refrigerant after being cooled by the condenser assembly, and is divided into three flow paths. The first flow path flows into the cold runner of the enthalpy-increasing heat exchanger after being throttled by the throttle valve group, and then absorbs the heat of the refrigerant in the hot runner of the enthalpy-increasing heat exchanger to form a gaseous refrigerant, and flows into the enthalpy-increasing port of the twin-cylinder compressor; the second flow path flows into the first evaporator assembly after being throttled by the first expansion valve, and then absorbs the heat of the air in the first temperature zone to evaporate into a gaseous refrigerant, and then flows back to the first suction port of the twin-cylinder compressor after passing through the four-way valve, that is, the first temperature zone refrigeration is completed; the third flow flows into the second evaporator assembly after being throttled by the second expansion valve, and then absorbs the heat of the air in the second temperature zone to evaporate into a gaseous refrigerant and then flows into the second suction port of the twin-cylinder compressor, that is, the second temperature zone refrigeration is completed.

[0040] Second temperature zone single opening refrigeration mode: In the above-mentioned second temperature zone-first temperature zone co-opening refrigeration mode, close the first expansion valve and only operate the first flow path and the third flow path to achieve the second temperature zone single opening refrigeration mode.

[0041] First temperature zone single opening refrigeration mode: In the above-mentioned second temperature zone-first temperature zone co-opening refrigeration mode, close the second expansion valve and only operate the first flow path and the second flow path to achieve the first temperature zone single opening refrigeration mode.

[0042] Single defrost mode in the first temperature zone: the high-temperature gaseous refrigerant discharged from the two-cylinder compressor enters the first evaporator assembly after passing through the four-way valve to release heat and defrost, and then passes through the first expansion valve throttling and successively passes through the enthalpy increase heat exchanger and the condenser assembly to enter the four-way valve to reverse and flow back to the first suction port of the two-cylinder compressor, thus realizing single defrost in the first temperature zone. At this time, the second expansion valve is closed, which can effectively avoid the temperature rise in the second temperature zone caused by defrosting in the first temperature zone, reduce the frequent start and stop of the system, and thus reduce energy consumption.

[0043] In summary, the present invention has at least the following beneficial effects:

[0044] 1. When the first temperature zone and the second temperature zone are opened simultaneously or separately for cooling, the gaseous refrigerant after heat exchange in the enthalpy increase heat exchanger can flow back to the enthalpy increase port of the compressor to recover the heat released during the compression process, reduce energy consumption, and significantly improve the energy efficiency of the compressor, thereby greatly improving the stability and reliability of the system operation.

[0045] 2. Integrating the enthalpy increase system and the heat pump system into one refrigeration system can meet more practical usage needs and greatly increase the types of refrigeration system operation modes.

[0046] 3. An expansion valve is installed in front of the entrance of the dual evaporator. By adjusting the opening of the expansion valve, the flow of refrigerant entering the evaporator can be controlled, thereby reducing the cost while increasing the evaporation temperature of the dual evaporator, thereby effectively avoiding frosting of the dual evaporator and greatly reducing energy consumption.

[0047] 4. When the first temperature zone is defrosted, closing the second temperature zone pipeline can effectively avoid the temperature rise of the second temperature zone caused by defrosting the first temperature zone, reduce the frequent start and stop of the system, and thus reduce energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0049] Figure 1 A schematic diagram of the structure of a dual-evaporator refrigeration system provided by the present invention;

[0050] Figure 2 It is a schematic diagram of a dual-evaporator refrigeration system in a second temperature zone-first temperature zone co-opening refrigeration mode;

[0051] Figure 3 It is a schematic diagram of a dual-evaporator refrigeration system in a second temperature zone single-opening refrigeration mode;

[0052] Figure 4 It is a schematic diagram of a dual-evaporator refrigeration system in a first temperature zone single-opening refrigeration mode;

[0053] Figure 5 It is a schematic diagram of a dual-evaporator refrigeration system in a single-opening defrost mode in the first temperature zone;

[0054] Figure 6 It is the control logic diagram of the refrigeration mode of the dual evaporator refrigeration system;

[0055] Figure 7 Defrost mode control logic diagram for dual evaporator refrigeration system.

[0056] Reference numerals:

[0057] 1-two-cylinder compressor; 2-four-way valve; 3-condensing fan; 4-condenser; 5-enthalpy-increasing heat exchanger; 6-drying filter; 7-second solenoid valve; 8-thermal expansion valve; 9-first expansion valve; 10-first evaporator; 11-first evaporating fan; 12-first indoor temperature sensor; 13-first coil temperature sensor; 14-second expansion valve; 15-second evaporator; 16-second evaporating fan; 17-second indoor temperature sensor; 18-second coil temperature sensor; 19-first solenoid valve;

[0058] D-one-way port; E-two-way port; S-three-way port; C-four-way port. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] The core of the present invention is to provide a dual-evaporator refrigeration system, which can reduce energy consumption and improve the stability and reliability of system operation.

[0061] Another core of the present invention is to provide a refrigeration device including the above-mentioned dual-evaporator refrigeration system, and also to provide a control method applied to the above-mentioned dual-evaporator refrigeration system.

[0062] Please refer to Figure 1 The present invention provides a dual-evaporator refrigeration system, including a dual-cylinder compressor 1, a four-way valve 2, a condenser assembly, an enthalpy-increasing heat exchanger 5, a first evaporator assembly for installation in a first temperature zone, and a second evaporator assembly for installation in a second temperature zone. It can be understood that the first temperature zone can be used as an ultra-low temperature zone (or freezing zone), and the second temperature zone can be used as a low temperature zone (or refrigeration zone). Here, the low temperature zone and the ultra-low temperature zone are relative, and the temperature of the low temperature zone will be higher than the temperature of the ultra-low temperature zone.

[0063] The exhaust port of the two-cylinder compressor 1 is connected to a port D of the four-way valve 2, and the four-way port C of the four-way valve 2 is connected to the condenser assembly and the hot runner inlet of the enthalpy-increasing heat exchanger 5 in sequence. The hot runner outlet of the enthalpy-increasing heat exchanger 5 is connected to the connecting pipeline. Specifically, the connecting pipeline connected to the hot runner outlet of the enthalpy-increasing heat exchanger 5 can be divided into three branches:

[0064] The first branch is connected to the cold flow channel of the enthalpy-increasing heat exchanger 5 and the enthalpy-increasing port of the twin-cylinder compressor 1 in sequence through the throttle valve group.

[0065] The second branch is connected to the first evaporator assembly and the second port E of the four-way valve 2 in sequence through the first expansion valve 9, and the three-way port S of the four-way valve 2 is connected to the first suction port of the two-cylinder compressor 1;

[0066] The third branch is connected to the second evaporator assembly and the second air intake port of the two-cylinder compressor 1 in sequence through the second expansion valve 14 .

[0067] It should be noted that the twin-cylinder compressor 1 has an enthalpy increase port for introducing enthalpy increase gas to recover the heat released during the compression process and reduce the work done by the compressor, thereby facilitating the stable operation of the refrigeration system with dual temperature zones and saving system energy consumption. In addition, the twin-cylinder compressor 1 has a first air intake port and a second air intake port, which are respectively connected to two independent cylinders. The two cylinders can compress the refrigerant at the same time, thereby improving the efficiency of the compressor, which is beneficial to improving the refrigeration efficiency of the refrigeration system.

[0068] The function of the condenser assembly is to cool and convert the high-temperature gaseous refrigerant into a liquid state to achieve refrigeration. The enthalpy-increasing heat exchanger 5 includes a hot runner and a cold runner that are adjacently arranged and can exchange heat with each other. The two respectively allow hot fluid and cold fluid to pass through and achieve efficient heat exchange between hot fluid and cold fluid. Exemplarily, the enthalpy-increasing heat exchanger 5 can adopt a plate heat exchanger. The function of the evaporator assembly is to evaporate the low-temperature refrigerant and convert it into a gaseous state, so that the indoor gas is cooled and cooled, thereby achieving the effect of indoor refrigeration. Therefore, the first evaporator assembly is used to be installed in the first temperature zone, so that the refrigeration of the first temperature zone can be achieved, and the second evaporator assembly is used to be installed in the second temperature zone, so that the refrigeration of the second temperature zone can be achieved. The throttling valve group, the first expansion valve 9 and the second expansion valve 14 can all play a throttling and pressure-reducing role, that is, the liquid refrigerant is throttled through it to become a low-temperature and low-pressure wet steam (or a gas-liquid mixture).

[0069] The four-way valve 2 includes four ports, namely, a port D, a port E, a port S and a port C. The four ports can be switched and connected to change the flow direction of the refrigerant. In this way, when the port D of the four-way valve 2 is connected to its port C and the port E of the four-way valve 2 is connected to its port S, the high-temperature gaseous refrigerant discharged from the two-cylinder compressor 1 enters the condenser assembly through the port D of the four-way valve 2 and its port C, and after being cooled by the condenser assembly, enters the hot runner of the enthalpy-increasing heat exchanger 5 for heat exchange to form a low-temperature liquid refrigerant. The low-temperature liquid refrigerant can flow into the second branch, pass through the first expansion valve 9 for throttling, and then flow into the first evaporator assembly for heat absorption and refrigeration, and then flow back to the first air intake port of the two-cylinder compressor 1 through the port E of the four-way valve 2 and its port S, thus completing the refrigeration in the first temperature zone. When the first port D of the four-way valve 2 is connected with its second port E, and the four-way port C of the four-way valve 2 is connected with its three-way port S, the high-temperature gaseous refrigerant discharged from the two-cylinder compressor 1 flows into the first evaporator assembly through the first port D and the second port E of the four-way valve 2 to release heat and defrost, and then passes through the first expansion valve 9 for throttling, passes through the enthalpy increase heat exchanger 5 and the condenser assembly in turn to enter the four-way port C of the four-way valve 2, and then flows back to the first suction port of the two-cylinder compressor 1 through the three-way port S of the four-way valve 2, thereby realizing single-opening defrosting in the first temperature zone.

[0070] Therefore, the present invention can adjust the flow direction of the refrigerant by the four-way valve 2 to achieve the switching between cooling and heating of the first evaporator component in the first temperature zone. The present invention is a heat pump refrigeration system that can achieve cooling and heating functions for the first temperature zone to meet more practical usage needs.

[0071] Regarding the specific configuration of the condenser assembly, based on the above embodiments, please refer to Figure 1 The condenser assembly includes a condenser 4 and a condensing fan 3 arranged on one side of the condenser 4.

[0072] Among them, the condensing fan 3 and the condenser 4 can both be installed on the outdoor side. The four-way port C of the four-way valve 2 is connected to the condenser 4 and the hot runner inlet of the enthalpy increase heat exchanger 5 in sequence. The condensing fan 3 can be set on the air inlet side or the air outlet side of the condenser 4. The outdoor air is sucked into the condenser 4 through high-speed rotation, taking away the heat generated by the refrigerant in the condensation process, and changing the refrigerant from gas to liquid to achieve a cooling effect.

[0073] Regarding the specific configuration of the first evaporator assembly, based on the above embodiment, please refer to Figure 1 The first evaporator assembly includes a first evaporator 10 and a first evaporation fan 11 arranged at one side of the first evaporator 10 .

[0074] Among them, the first evaporation fan 11 and the first evaporator 10 can both be installed on the indoor side (that is, in the first temperature zone), and the second branch is connected to the first evaporator 10 and the second port E of the four-way valve 2 in sequence through the first expansion valve 9. The first evaporation fan 11 can be set on the air inlet side or the air outlet side of the first evaporator 10, and introduces the hot air in the first temperature zone into the first evaporator 10 through high-speed rotation. The hot air is released into the room after heat exchange with the first evaporator 10, thereby achieving the effect of cooling the first temperature zone.

[0075] Regarding the specific arrangement of the second evaporator assembly, on the basis of the above embodiment, the second evaporator assembly includes a second evaporator 15 and a second evaporation fan 16 disposed at one side of the second evaporator 15 .

[0076] Among them, the second evaporator fan 16 and the second evaporator 15 can be installed on the indoor side (that is, in the second temperature zone), and the third branch connects the second evaporator 15 and the second air intake port of the two-cylinder compressor 1 in sequence through the second expansion valve 14. The second evaporator fan 16 can be set on the air inlet side or the air outlet side of the second evaporator 15, and introduces the hot air in the second temperature zone into the second evaporator 15 through high-speed rotation. The hot air is released into the room after heat exchange with the second evaporator 15, thereby achieving the effect of cooling the second temperature zone.

[0077] Regarding the specific setting of the throttle valve group, based on the above embodiment, please refer to Figure 1 The throttle valve group includes a third solenoid valve and a thermal expansion valve 8, which are arranged on the first branch in sequence along the direction from the hot runner outlet of the enthalpy increase heat exchanger 5 to the cold runner inlet thereof.

[0078] Specifically, the thermal expansion valve 8 is installed on the first branch, and a part of the refrigerant discharged from the hot flow channel of the enthalpy-increasing heat exchanger 5 is throttled by the thermal expansion valve 8 to become low-temperature and low-pressure wet steam (or gas-liquid mixture), and then flows into the cold flow channel of the enthalpy-increasing heat exchanger 5 to absorb heat and evaporate into low-temperature and low-pressure gaseous refrigerant. The low-temperature and low-pressure gaseous refrigerant flows into the two-cylinder compressor 1 through the enthalpy-increasing port to achieve the enthalpy-increasing function. The thermal expansion valve 8 maintains a certain degree of superheat to prevent liquid refrigerant from entering the two-cylinder compressor 1 and causing liquid hammer. Since the thermal expansion valve 8 maintains a certain degree of superheat, the thermal expansion valve 8 cannot be completely closed. Therefore, a third solenoid valve located before the thermal expansion valve 8 is set on the first branch to control the on and off of the first branch.

[0079] In order to increase the service life of the twin-cylinder compressor 1, based on the above embodiment, please refer to Figure 1 The pipeline connecting the three-way port S of the four-way valve 2 and the first air intake port is connected to the third pipeline located between the second evaporator assembly and the second air intake port by an auxiliary pipeline, and a first solenoid valve 19 connected to the control unit signal is provided on the auxiliary pipeline.

[0080] Specifically, in the second temperature zone single-opening refrigeration mode, the first temperature zone single-opening refrigeration mode or the first temperature zone single-opening defrosting mode, opening the first solenoid valve 19 can allow the two air intake ports of the two-cylinder compressor 1 to inhale gas, thereby making the air intake volume of the two cylinders of the two-cylinder compressor 1 higher than the minimum threshold, which is beneficial to improving the working efficiency and service life of the compressor.

[0081] The dual evaporator refrigeration system provided in the above embodiment can operate in the following working modes:

[0082] Please refer to Figure 2 , the second temperature zone-the first temperature zone are opened at the same time in the refrigeration mode: the exhaust port of the twin-cylinder compressor 1 discharges high-temperature gaseous refrigerant, and the high-temperature gaseous refrigerant enters the condenser 4 through the one-way port D and the four-way port C of the four-way valve 2. The condensing fan 3 runs at a high speed to accelerate the forced heat exchange between the condenser 4 and the outdoor air, and the high-temperature gaseous refrigerant is changed into a medium-temperature liquid refrigerant. The medium-temperature liquid refrigerant enters the hot runner of the enthalpy-increasing heat exchanger 5 for heat exchange to form a low-temperature liquid refrigerant. The low-temperature liquid refrigerant is divided into three flow paths: the first flow path flows into the cold runner of the enthalpy-increasing heat exchanger 5 after throttling by the throttle valve group, and then absorbs the heat of the refrigerant in the hot runner of the enthalpy-increasing heat exchanger 5 to form a gaseous refrigerant, and flows into the twin-cylinder compressor 1 enthalpy increase port; the second flow path flows into the first evaporator 10 after throttling through the first expansion valve 9, and the first evaporation fan 11 runs at a high speed to realize the strong convection heat exchange between the first evaporator 10 and the indoor air in the first temperature zone, so as to achieve the effect of cooling the first temperature zone. The refrigerant absorbs heat and evaporates into a gaseous refrigerant. The gaseous refrigerant flows back to the first air intake port of the two-cylinder compressor 1 through the two-way port E and the three-way port S of the four-way valve 2, thus completing the cooling of the first temperature zone; the third flow path flows into the second evaporator 15 after throttling through the second expansion valve 14, and the second evaporation fan 16 runs at a high speed to realize the strong convection heat exchange between the second evaporator 15 and the indoor air in the second temperature zone, so as to achieve the effect of cooling the second temperature zone. It should be noted that the refrigerant flowing back into the compressor is discharged from the compressor after compression is completed, thus achieving cycle refrigeration.

[0083] Please refer to Figure 3 , Second temperature zone single opening refrigeration mode: In the above-mentioned second temperature zone-first temperature zone co-opening refrigeration mode, close the first expansion valve 9, open the first solenoid valve 19, and only run the first flow path and the third flow path to achieve the second temperature zone single opening refrigeration mode.

[0084] Please refer to Figure 4 , first temperature zone single opening refrigeration mode: in the above-mentioned second temperature zone-first temperature zone co-opening refrigeration mode, close the second expansion valve 14, open the first solenoid valve 19, and only run the first flow path and the second flow path to achieve the first temperature zone single opening refrigeration mode.

[0085] Please refer to Figure 5, single defrosting mode in the first temperature zone: the high-temperature gaseous refrigerant discharged from the twin-cylinder compressor 1 flows into the first evaporator 10 through the first port D and the second port E of the four-way valve 2 to release heat and defrost, and then passes through the first expansion valve 9 to throttle, and then passes through the enthalpy increase heat exchanger 5 and the condenser 4 to enter the four-way port C of the four-way valve 2, and then flows back to the first air intake port of the twin-cylinder compressor 1 through the three-way port S of the four-way valve 2, that is, single defrosting in the first temperature zone is realized. At this time, the second expansion valve 14 is closed, which can effectively avoid the temperature rise of the second temperature zone caused by defrosting in the first temperature zone, and can reduce the frequent start and stop of the system, thereby reducing energy consumption.

[0086] To realize automatic control of the refrigeration mode of the refrigeration system, based on the above embodiment, please refer to Figure 1 The present invention also includes a first indoor temperature sensor 12 for installation in the first temperature zone and a second indoor temperature sensor 17 for installation in the second temperature zone. The first indoor temperature sensor 12, the second indoor temperature sensor 17, the four-way valve 2, the throttle valve group, the first expansion valve 9, and the second expansion valve 14 are all signal-connected to the control unit.

[0087] Specifically, the first indoor temperature sensor 12 is used to detect the indoor temperature of the first temperature zone in real time, and transmit the signal to the control unit, and the second indoor temperature sensor 17 is used to detect the indoor temperature of the second temperature zone in real time, and transmit the signal to the control unit. For example, if the indoor temperature of the second temperature zone is greater than the second set temperature, it means that the second temperature zone needs to be refrigerated, and the first port D of the four-way valve 2 is controlled to be connected with its four-way port C, the second port E of the four-way valve 2 is connected with its three-way port S, and the two-cylinder compressor 1, the condensing fan 3, the second solenoid valve 7, the second expansion valve 14, and the second evaporating fan 16 are turned on, so that the second temperature zone refrigeration mode can be realized. Therefore, the above-mentioned settings can realize the automatic control of the refrigeration mode of the refrigeration system, so that the refrigeration system has better intelligence and stability.

[0088] To realize the automatic control of the defrost mode of the refrigeration system, based on the above embodiment, please refer to Figure 1 The present invention further comprises a first coil temperature sensor 13 provided in the first evaporator assembly and a second coil temperature sensor 18 provided in the second evaporator assembly, and both the first coil temperature sensor 13 and the second coil temperature sensor 18 are connected to the control unit through signals.

[0089] Specifically, frost on the evaporator usually occurs on the coil. The first coil temperature sensor 13 is arranged on the coil of the first evaporator 10, and is used to detect the coil temperature of the first evaporator 10, that is, the coil temperature of the first temperature zone, in real time, and transmit the signal to the control unit. The second coil temperature sensor 18 is arranged on the coil of the second evaporator 15, and is used to detect the coil temperature of the second evaporator 15, that is, the coil temperature of the second temperature zone, in real time, and transmit the signal to the control unit. If the coil temperature of the first temperature zone is less than the third set temperature, it means that the first temperature zone needs to be defrosted. The first port D of the four-way valve 2 is controlled to be connected with its second port E, and the four-way port C of the four-way valve 2 is connected with its three-way port S. The first solenoid valve 19 is opened, and the second solenoid valve 7 and the second expansion valve 14 are closed, so that the above-mentioned first temperature zone single opening defrost mode can be realized. In addition, the valve opening size of the second expansion valve 14 can be adjusted according to the coil temperature of the second temperature zone, so that the evaporation temperature of the second temperature zone is maintained within a reasonable temperature range, and the second temperature zone is prevented from frosting and increasing energy consumption. Therefore, the above-mentioned setting can realize automatic control of the defrosting mode in the first temperature zone, and can also maintain the evaporation temperature in the second temperature zone within a reasonable range, thereby improving the stability and reliability of the system operation.

[0090] Based on the above examples, please refer to Figure 1 A drying filter 6 is provided on the connecting pipeline communicating with the hot runner outlet of the enthalpy-increasing heat exchanger 5 .

[0091] Specifically, the filter drier 6 mainly plays the role of impurity filtering and water absorption. It can remove mechanical impurities in the refrigerant and prevent the mechanical impurities from entering the evaporator in different temperature zones, thereby ensuring the safe and stable operation of the refrigeration system.

[0092] The present invention also provides a refrigeration device including the dual evaporator refrigeration system disclosed in the above embodiment. The refrigeration device is suitable for scenarios with a first temperature zone and a second temperature zone, for example, a refrigerator or a refrigeration truck, wherein the freezing zone of the two is the first temperature zone and the refrigeration zone is the second temperature zone.

[0093] The present invention also provides a control method, which is applied to the dual evaporator refrigeration system disclosed in the above embodiment, please refer to Figure 6 , the specific steps of the control method include:

[0094] S1: Turn on the first evaporation fan in the first temperature zone and the second evaporation fan in the second temperature zone;

[0095] S2: Obtaining the indoor temperature of the second temperature zone (indicated as the indoor temperature of the low temperature zone in the figure, i.e., the second temperature zone can be the low temperature zone) and the indoor temperature of the first temperature zone (indicated as the indoor temperature of the ultra-low temperature zone in the figure, i.e., the first temperature zone can be the ultra-low temperature zone);

[0096] Specifically, the control unit inputs the second set temperature Ta and the first set temperature Tb, uses the first indoor temperature sensor to detect the indoor temperature T2 of the first temperature zone in real time and transmits it to the control unit, and uses the second indoor temperature sensor to detect the indoor temperature T1 of the second temperature zone in real time and transmit it to the control unit.

[0097] S3: Determine whether the indoor temperature T1 in the second temperature zone is greater than the second set temperature Ta;

[0098] S4: If not, return to step S2;

[0099] S5: If yes, determine whether the first temperature zone is running single-open cooling;

[0100] It should be noted that if T1>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 single cooling at this time.

[0101] S6: If the first temperature zone operates in single-open cooling mode, the second expansion valve is opened and the first solenoid valve is closed until the indoor temperature of the second temperature zone is less than or equal to the second set temperature;

[0102] Specifically, if the first temperature zone operates with independent refrigeration, it means that the dual-cylinder compressor 1, the condensing fan 3, and the second solenoid valve 7 are all in the open state. The second expansion valve 14 is directly opened, and the first solenoid valve 19 is closed, so that the second temperature zone can be cooled and cooled. At this time, the system is in the second temperature zone-first temperature zone co-open refrigeration mode.

[0103] S7: After executing the above step S6, determine whether the indoor temperature in the second temperature zone is less than or equal to the second set temperature. If so, close the second expansion valve and open the first solenoid valve; if not, continue to execute the above step S6.

[0104] Specifically, during the system operation of the second temperature zone-first temperature zone co-opening cooling mode, if T1≤Ta, it means that the indoor temperature of the second temperature zone meets the requirements, the second expansion valve 14 is closed, and the first solenoid valve 19 is opened to end the second temperature zone refrigeration, and the system operates the first temperature zone single opening cooling mode. If not, the second temperature zone-first temperature zone co-opening cooling mode is maintained.

[0105] S8: If the first temperature zone does not operate single-open cooling, the two-cylinder compressor, the condensing fan, the first solenoid valve, the second solenoid valve, and the second expansion valve are turned on; that is, if the first temperature zone does not operate single-open cooling, the two-cylinder compressor, the condenser assembly, the throttle valve assembly, and the second expansion valve are turned on until the indoor temperature in the second temperature zone is less than or equal to the second set temperature.

[0106] It should be noted that the first temperature zone does not run independent refrigeration, which means that the refrigeration mode is not turned on in both the second temperature zone and the first temperature zone. By turning on the two-cylinder compressor 1, the condensing fan 3, the first solenoid valve 19, the second solenoid valve 7, and the second expansion valve 14, the second temperature zone single refrigeration mode can be operated.

[0107] S9: After executing step S8, determine whether the indoor temperature of the second temperature zone is less than or equal to the second set temperature. If not, continue to execute the above step S8. If yes, determine whether a command to exit the cooling mode is obtained. If the command to exit the cooling mode is obtained, turn off the first evaporating fan in the first temperature zone and the second evaporating fan in the second temperature zone to exit the cooling mode. If the command to exit the cooling mode is not obtained, return to step S2.

[0108] Specifically, after executing the above step S8, the system runs the second temperature zone single-open cooling mode. If T1≤Ta, it means that the indoor temperature of the second temperature zone meets the requirements. If the instruction to exit the cooling mode is obtained, the fans in the second temperature zone and the first temperature zone are turned off to exit the cooling mode. If the instruction to exit the cooling mode is not obtained, the second temperature zone independent cooling mode is stopped, that is, the two-cylinder compressor 1, the condensing fan 3, the first solenoid valve 19, the second solenoid valve 7, and the second expansion valve 14 are turned off and on, and then the system returns to step S2.

[0109] S10: After executing the above step S1, determine whether the indoor temperature T2 in the first temperature zone is greater than the first set temperature Tb;

[0110] S11: If not, return to step S2;

[0111] S12: If yes, determine whether the second temperature zone is running single-open cooling;

[0112] S13: If the second temperature zone operates in single-open cooling mode, the first expansion valve is opened and the first solenoid valve is closed until the indoor temperature of the first temperature zone is less than or equal to the first set temperature;

[0113] Specifically, if the second temperature zone operates with independent refrigeration, it means that the dual-cylinder compressor 1, the condensing fan 3, and the second solenoid valve 7 are all in the open state. The first expansion valve 9 is directly opened, and the first solenoid valve 19 is closed to cool the first temperature zone. At this time, the system is in the second temperature zone-first temperature zone co-open refrigeration mode.

[0114] S14: After executing step S13, determine whether the indoor temperature in the first temperature zone is less than or equal to the first set temperature. If so, close the second expansion valve and open the first solenoid valve; if not, continue to execute step S13.

[0115] Specifically, after executing the above step S13, that is, the system runs the second temperature zone-first temperature zone co-opening refrigeration mode, if T2≤Tb, it means that the indoor temperature of the first temperature zone meets the requirements, the first expansion valve 9 is closed, and the first solenoid valve 19 is opened to end the refrigeration of the first temperature zone, and the system runs the second temperature zone single opening refrigeration mode. If T2>Tb, it means that the indoor temperature of the first temperature zone is still higher than the first set temperature, and the second temperature zone-first temperature zone co-opening refrigeration mode continues to run.

[0116] S15: If the second temperature zone does not operate single-open cooling, the double-cylinder compressor, condensing fan, first solenoid valve, second solenoid valve, and first expansion valve are turned on to operate the single-open cooling mode of the first temperature zone. That is, if the second temperature zone does not operate single-open cooling, the double-cylinder compressor, condenser assembly, throttle valve assembly, and first expansion valve are turned on until the indoor temperature of the first temperature zone is less than or equal to the first set temperature.

[0117] S16: After executing step S15, determine whether the indoor temperature in the first temperature zone is less than or equal to the first set temperature. If not, return to step S15; if so, determine whether the refrigeration system has exited the refrigeration mode. If the exit refrigeration mode instruction is obtained, turn off the fans in the second temperature zone and the first temperature zone to exit the refrigeration mode. If the exit refrigeration mode instruction is not obtained, stop the single-open refrigeration mode in the first temperature zone, that is, turn off and on the two-cylinder compressor 1, the condensing fan 3, the first solenoid valve 19, the second solenoid valve 7, and the first expansion valve 9, and then return to step S2.

[0118] Therefore, the above control method can realize the second temperature zone and first temperature zone simultaneous cooling mode, the second temperature zone single cooling mode and the first temperature zone single cooling mode, which expands the refrigeration conditions of the refrigeration system and is beneficial to improving the user experience.

[0119] Please refer to Figure 7 The control method provided by the present invention further includes the following specific steps:

[0120] S1': obtaining the coil temperature of the first temperature zone (indicated as the coil temperature of the ultra-low temperature zone in the figure);

[0121] It should be noted that no matter the second temperature zone and the first temperature zone are opened simultaneously or only opened to operate in cooling mode, the control unit will input the third set temperature Tc in advance, and the first coil temperature sensor 13 is used to detect the first temperature zone coil temperature T3 in real time.

[0122] S2': Determine whether the coil temperature in the first temperature zone is less than the third set temperature;

[0123] S3': If the coil temperature in the first temperature zone is lower than the third set temperature, the first port D and the second port E of the four-way valve 2 are connected, the four-way port C and the three-way port S of the four-way valve 2 are connected, and the second solenoid valve 7 and the second expansion valve 14 are closed, that is, the first temperature zone single-opening defrosting mode is operated for a period of defrosting time;

[0124] S4': Determine whether the coil temperature of the first temperature zone is greater than or equal to the third set temperature. If so, connect the first port D of the four-way valve 2 and its four-way port C, connect the second port E of the four-way valve 2 and its three-way port S, open the second solenoid valve 7 and the second expansion valve 14, that is, operate the second temperature zone-first temperature zone co-open cooling mode; if not, continue to operate the above step S3';

[0125] S5': Determine whether the defrost time is greater than the preset defrost time. If so, connect the first port D of the four-way valve 2 and its four-way port C, connect the second port E of the four-way valve 2 and its three-way port S, open the second solenoid valve 7 and the second expansion valve 14, that is, run the second temperature zone-first temperature zone simultaneous refrigeration mode; if not, continue to run the above step S3'.

[0126] It should be noted that the above steps S4' and S5' can be performed selectively.

[0127] Therefore, when the first temperature zone is opened for defrosting, the second temperature zone pipeline is closed, which can effectively avoid the second temperature zone from heating up, so as to effectively ensure that the temperature of the second temperature zone is stable when the first temperature zone is opened for defrosting, which is beneficial to energy saving and stable operation of the system.

[0128] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0129] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0130] The above is a detailed introduction to a dual-evaporator refrigeration system, refrigeration equipment and control method thereof provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A dual evaporator refrigeration system, characterized in that: It comprises a double-cylinder compressor (1), a four-way valve (2), a condenser assembly, an enthalpy-increasing heat exchanger (5), 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 a port (D) of the four-way valve (2), the four-way port (C) of the four-way valve (2) is connected to the condenser assembly and the hot runner inlet of the enthalpy-increasing heat exchanger (5) in sequence, the hot runner outlet of the enthalpy-increasing heat exchanger (5) is connected to a connecting pipeline, and the connecting pipeline is divided into three branches: The first branch is connected in sequence through the throttle valve group to the cold flow channel of the enthalpy-increasing heat exchanger (5) and the enthalpy-increasing port of the dual-cylinder compressor (1); The second branch is connected to the first evaporator assembly and the second port (E) of the four-way valve (2) in sequence through the first expansion valve (9), and the three-way port (S) of the four-way valve (2) is connected to the first suction port of the two-cylinder compressor (1); The third branch is connected in sequence to the second evaporator assembly and the second air intake port of the two-cylinder compressor (1) through the second expansion valve (14).

2. The dual evaporator refrigeration system according to claim 1, characterized in that: It also includes a first indoor temperature sensor (12) for installation in the first temperature zone and a second indoor temperature sensor (17) for installation in the second temperature zone, wherein the first indoor temperature sensor (12), the second indoor temperature sensor (17), the four-way valve (2), the throttling valve group, the first expansion valve (9), and the second expansion valve (14) are all connected to the control unit through signals.

3. The dual evaporator refrigeration system according to claim 1, characterized in that: It also includes a first coil temperature sensor (13) provided on the first evaporator component and a second coil temperature sensor (18) provided on the second evaporator component, wherein the first coil temperature sensor (13) and the second coil temperature sensor (18) are both connected to a control unit via signals.

4. The dual evaporator refrigeration system according to claim 1, characterized in that: The pipeline connecting the three-way port (S) of the four-way valve (2) and the first air intake port is connected to the third pipeline located between the second evaporator assembly and the second air intake port by an auxiliary pipeline, and the auxiliary pipeline is provided with a first solenoid valve (19) connected to a control unit signal.

5. The dual evaporator refrigeration system according to claim 1, characterized in that: The throttle valve group comprises a second solenoid valve (7) and a thermal expansion valve (8), which are arranged in sequence on the first branch along the direction from the hot runner outlet to the cold runner inlet of the enthalpy increasing heat exchanger (5).

6. The dual evaporator refrigeration system according to claim 1, characterized in that: A drying filter (6) is provided on a connecting pipeline communicating with the hot runner outlet of the enthalpy-increasing heat exchanger (5).

7. The dual evaporator refrigeration system according to any one of claims 1 to 6, characterized in that: The condenser assembly comprises a condenser (4) and a condensing fan (3) arranged on one side of the condenser (4); And / or, the first evaporator assembly comprises a first evaporator (10) and a first evaporation fan (11) arranged on one side of the first evaporator (10); And / or, the second evaporator assembly comprises a second evaporator (15) and a second evaporation fan (16) arranged on one side of the second evaporator (15).

8. A refrigeration device, characterized in that: A dual evaporator refrigeration system comprising any one of claims 1 to 7.

9. A control method, characterized in that: Applied to the dual evaporator refrigeration system according to any one of claims 1 to 7 above, the control method comprises: Turning on the first evaporator assembly and the second evaporator assembly; Obtaining the indoor temperature of the second temperature zone and the indoor temperature of the first temperature zone; When the indoor temperature of the second temperature zone is greater than the second set temperature, it is determined whether the first temperature zone is in single-open cooling operation; If yes, open the second expansion valve until the indoor temperature in the second temperature zone is less than or equal to the second set temperature; If not, the dual-cylinder compressor, the condenser assembly, the throttle valve assembly, and the second expansion valve are turned on until the indoor temperature in the second temperature zone is less than or equal to the second set temperature; When the indoor temperature of the first temperature zone is greater than the first set temperature, it is determined whether the second temperature zone is in single-open cooling operation; If yes, open the first expansion valve until the indoor temperature in the first temperature zone is less than or equal to the first set temperature; If not, the dual-cylinder compressor, the condenser assembly, the throttle valve assembly, and the first expansion valve are turned on until the indoor temperature in the first temperature zone is less than or equal to the first set temperature.

10. The control method according to claim 9, characterized in that: The control method further comprises: Get the coil temperature of the first temperature zone; When the temperature of the coil in the first temperature zone is lower than the third set temperature, the first port of the four-way valve and its second port are connected, the four-way port of the four-way valve and its three-way port are connected, the throttling valve group and the second expansion valve are closed, and the defrosting operation is performed for a period of time; Determine whether the coil temperature in the first temperature zone is greater than or equal to the third set temperature, or determine whether the defrost time is greater than the preset defrost time; If so, connect one port of the four-way valve with its four-way port, connect the two port of the four-way valve with its three-way port, and open the throttling valve group and the second expansion valve.

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