Evaporative low-temperature refrigeration device and control method

Abstract

The embodiment of the application provides an evaporative low-temperature refrigeration device and a control method, and relates to the technical field of refrigeration equipment. The evaporative low-temperature refrigeration device comprises a compressor, an oil separator, an evaporative condensing mechanism, an economizer, an economizer electromagnetic valve and an indoor terminal assembly; the compressor, the oil separator, the evaporative condensing mechanism, the economizer and the economizer electromagnetic valve are sequentially connected; the economizer is connected with the compressor and the indoor terminal assembly respectively; and the indoor terminal assembly is connected with the compressor. The indoor terminal assembly comprises at least one indoor terminal mechanism, each indoor terminal mechanism is installed in a preset cold storage correspondingly, the indoor terminal mechanism comprises a cold air fan and a waterway electromagnetic valve, a water tank, a defrosting water pump and the waterway electromagnetic valve are sequentially connected, and the water in the water tank is transported to the corresponding cold air fan for defrosting through the defrosting water pump and the waterway electromagnetic valve. The evaporative low-temperature refrigeration device can reduce the temperature fluctuation of a warehouse, and realizes the technical effect of improving the defrosting efficiency of a low-temperature cold storage.

Description

Technical Field

[0001] This application relates to the field of refrigeration equipment technology, and more specifically, to an evaporative cryogenic freezing device and its control method. Background Technology

[0002] Currently, most low-temperature cold storage facilities use electric or hot gas defrosting. However, hot gas defrosting has complex piping and consumes a lot of compressor power, while electric defrosting has high power consumption. In addition, a single refrigeration unit corresponds to different storage temperatures (0℃ fresh-keeping storage, -18℃ cold storage, -35℃ quick-freezing storage), making it unsuitable to use evaporation temperature as the basis for defrosting. Generally, the running time of each storage is calculated separately as a fixed defrosting condition, such as defrosting once every 3 hours in a quick-freezing storage. However, the timing method does not take into account the moisture content of the fresh air introduced when the door is opened (during the rainy season), as well as the moisture content brought by the newly arrived frozen goods (fresh fish, vegetables). The inaccuracy of the defrosting condition leads to untimely or frequent defrosting, consuming a lot of electricity on defrosting, and large fluctuations in the storage temperature. Summary of the Invention

[0003] The purpose of this application is to provide an evaporative low-temperature freezing device and control method, which can reduce temperature fluctuations in the cold storage and improve the defrosting efficiency of the low-temperature cold storage.

[0004] In a first aspect, embodiments of this application provide an evaporative low-temperature refrigeration device, including a compressor, an oil separator, an evaporative condensation mechanism, an economizer, an economizer solenoid valve, and an indoor terminal assembly;

[0005] The compressor, the oil separator, the evaporative condenser, the economizer, and the economizer solenoid valve are connected in sequence. The economizer is connected to the compressor and the indoor terminal assembly, respectively. The indoor terminal assembly is connected to the compressor. The refrigerant circulation is either sequentially through the compressor, the oil separator, the evaporative condenser, the economizer, the economizer solenoid valve, and the compressor, or sequentially through the compressor, the oil separator, the evaporative condenser, the economizer, the indoor terminal assembly, and the compressor.

[0006] The evaporative condensation mechanism includes a water tank and a defrosting water pump. The indoor terminal assembly includes at least one indoor terminal mechanism, and each indoor terminal mechanism is installed in a pre-set cold storage. The indoor terminal mechanism includes a cold air blower and a water circuit solenoid valve. The water tank, the defrosting water pump, and the water circuit solenoid valve are connected in sequence. The water in the water tank is transported to the corresponding cold air blower for defrosting through the defrosting water pump and the water circuit solenoid valve.

[0007] In the aforementioned process, the evaporative low-temperature refrigeration unit forms a refrigerant cycle through a compressor, oil separator, evaporative condenser, economizer, economizer solenoid valve, and indoor terminal components. Furthermore, the use of economizer supplementary gas circulation improves the efficiency of the single-stage screw compressor refrigeration cycle, increases cooling capacity, and reduces compressor discharge temperature. Additionally, when the indoor terminal components require defrosting, the defrosting water pump is activated, and the corresponding water circuit solenoid valve is opened, delivering the warmer water from the evaporative condenser's water tank to the corresponding air cooler. The defrosted and cooled water returns to the evaporative condenser's water tank for refrigeration circulation, reducing the condensing temperature of the refrigeration system and lowering the operating power consumption of the refrigeration unit. It also recovers the cooling energy from defrosting, improving refrigeration performance while increasing defrosting efficiency and reducing temperature fluctuations in the cold storage. Therefore, this evaporative low-temperature refrigeration unit can reduce temperature fluctuations in the cold storage, achieving the technical effect of improving the defrosting efficiency of the low-temperature cold storage.

[0008] Furthermore, the device also includes multiple temperature and humidity sensors. The preset cold storage is equipped with a return air door, a fresh air door, a defrost door, and an air outlet door. The preset cold storage is ventilated through an air duct. The multiple temperature and humidity sensors are respectively installed at the air outlet, the return air outlet, and the outdoor area of ​​the preset cold storage.

[0009] In the above implementation process, by introducing the preset temperature and humidity of the cold storage outlet air, return air, and the outside, and then taking into account the moisture content of the fresh air and the goods, the amount of frost at the current stage can be calculated. This can more effectively determine the conditions for entering defrosting, thereby avoiding the problem of inaccurate defrosting conditions leading to untimely or frequent defrosting, and solving the problems of consuming a lot of electricity on defrosting and large temperature fluctuations in the warehouse.

[0010] Furthermore, the device also includes a purification and disinfection mechanism, with the return air door and the fresh air door facing each other, the defrosting door and the air outlet door facing each other, and the air cooler disposed between the return air door and the air outlet door, and the purification and disinfection mechanism being matched and installed with the air cooler.

[0011] In the above process, the air passes through the purification and disinfection mechanism and the air cooler for disinfection and cooling before entering the preset cold storage, ensuring that the air entering the preset cold storage meets the temperature and cleanliness requirements.

[0012] Furthermore, the device also includes an expansion valve, which is connected to the economizer and the economizer solenoid valve.

[0013] Furthermore, the device also includes a liquid reservoir and a drying filter, with the evaporative condensation mechanism, the liquid reservoir, the drying filter, and the economizer connected in sequence.

[0014] Furthermore, the evaporative condensation mechanism also includes a fan, a water distributor, a plate-tube condenser, packing material, and a water pump. From top to bottom, the fan, the water distributor, the plate-tube condenser, the packing material, and the water tank are stacked in sequence, and the water pump is connected to the water distributor and the water tank respectively.

[0015] The air cooler is connected to the water tank, and the water from the defrost operation of the air cooler is recycled back to the water tank.

[0016] In the above process, water is pumped from the water tank to the water distributor. The water drips from the water distributor, the plate-tube condenser, and the packing in sequence, and is then recycled back to the water tank. The air flow efficiency is increased by the fan.

[0017] Furthermore, the types of the pre-designated cold storage include high-temperature cold storage and low-temperature cold storage;

[0018] When the indoor terminal mechanism is installed in the high-temperature freezer, the indoor terminal mechanism also includes an evaporation pressure regulating valve, which is connected to the air cooler and the compressor respectively.

[0019] When the indoor terminal mechanism is installed in the low-temperature freezer, the indoor terminal mechanism also includes a one-way valve, which is connected to the air cooler and the compressor respectively.

[0020] In the above process, evaporation pressure regulating valves and check valves are installed differently according to the different operating temperatures of the preset cold storage to ensure the refrigeration efficiency of the preset cold storage.

[0021] Furthermore, the indoor terminal mechanism also includes a thermal expansion valve, which is connected to the economizer and the air cooler respectively.

[0022] Furthermore, the indoor terminal mechanism also includes a dryer filter and a solenoid valve, with the thermal expansion valve, the dryer filter, the solenoid valve, and the air cooler connected in sequence.

[0023] Furthermore, the device also includes a gas-liquid separator, which is connected to the air cooler and the compressor respectively.

[0024] Secondly, embodiments of this application provide a control method for evaporative cryogenic freezing, applied to the evaporative cryogenic freezing apparatus described in any one of the first aspects, the control method comprising:

[0025] The operating time of the evaporative low-temperature refrigeration device, as well as the cold storage door opening time, inlet air humidity, outlet air humidity, and ambient humidity of the preset cold storage are obtained.

[0026] The cumulative frost amount is calculated based on the first preset formula, the running time, the cold storage door opening time, the inlet air humidity, the outlet air humidity, and the ambient humidity.

[0027] If the cumulative frost amount exceeds the frost amount threshold, then the evaporative low-temperature freezing device is subjected to defrosting treatment:

[0028] The air cooler is turned off within a preset defrosting time, and the defrosting water pump and the water circuit solenoid valve are turned on. The preset defrosting time is determined based on a second preset formula, the cumulative amount of frost, the preset temperature of the cold storage, the flow rate of the defrosting water, and the temperature difference between the inlet and outlet of the defrosting water.

[0029] After the defrosting process is completed, the air cooler is turned on for a preset time.

[0030] Control the evaporative cryogenic refrigeration device to operate in a preset refrigeration mode.

[0031] In the above implementation process, by introducing the cold storage door opening time, as well as the humidity of the incoming air, the humidity of the outgoing air, and the ambient humidity, the current cumulative frost amount is calculated. Combined with the set frost amount threshold, the conditions for entering defrost can be determined more effectively. Moreover, by quantitatively calculating the heat required for the cumulative frost to melt into water, and calculating and obtaining the heat that can be provided during defrost according to the second preset formula, the duration of defrost can be precisely controlled, avoiding excessive defrost or incomplete defrost, thus improving defrost efficiency.

[0032] Furthermore, the first preset formula is:

[0033] M=q×(di-do)×(T-t1)+q×(a×(dh-do)+(1-a)×(di-do))×t1;

[0034] Where M is the cumulative frost amount, t1 is the cold storage door opening time, T is the running time, di is the inlet air humidity, do is the outlet air humidity, dh is the ambient humidity, q is the air volume of the air cooler, and a is a preset coefficient.

[0035] The second preset formula is:

[0036] t2=(M×C×△t1+M×r)÷(G×1.163×△t2);

[0037] Wherein, t2 is the preset defrosting time, C is the specific heat capacity of ice, r is the heat of fusion of ice, Δt1 is the temperature difference between the preset cold storage and 0℃, G is the defrosting water flow rate, and Δt2 is the temperature difference between the inlet and outlet of the defrosting water.

[0038] Thirdly, embodiments of this application provide a control method for evaporative cryogenic freezing, applied to the evaporative cryogenic freezing apparatus described in any one of the first aspects, the control method comprising:

[0039] Acquire information on the opening status of the economizer solenoid valve, the compressor discharge temperature data, and the compressor load data;

[0040] Determine whether the economizer solenoid valve is in the open state based on the opening status information;

[0041] If the economizer solenoid valve is in the open state, the economizer solenoid valve will be closed when the exhaust temperature data is less than the first opening exhaust temperature threshold or the compressor load data is less than the load threshold.

[0042] If the economizer solenoid valve is in the closed state, the economizer solenoid valve will be opened when the exhaust temperature data is greater than or equal to the second opening exhaust temperature threshold or when the compressor load data is greater than the load threshold.

[0043] In the above implementation process, by setting an economizer and controlling the economizer solenoid valve according to the exhaust temperature data and compressor load, the efficiency of the single-stage screw compressor refrigeration cycle is improved, the refrigeration capacity is increased, and the compressor exhaust temperature is reduced.

[0044] Other features and advantages disclosed in this application will be set forth in the following description, or some features and advantages may be inferred from the description or determined without doubt, or may be learned by practicing the above-described technology disclosed in this application.

[0045] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0046] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of the structure of the evaporative cryogenic freezing device provided in the embodiments of this application;

[0048] Figure 2 This is a schematic diagram of the evaporative condensation mechanism provided in the embodiments of this application;

[0049] Figure 3A schematic diagram of the indoor terminal mechanism and the pre-set cold storage provided in the embodiments of this application;

[0050] Figure 4 A schematic flowchart illustrating a control method for evaporative cryogenic freezing provided in an embodiment of this application;

[0051] Figure 5 This is a schematic flowchart of another evaporative cryogenic freezing control method provided in an embodiment of this application. Detailed Implementation

[0052] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0053] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0054] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0055] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or a point connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0056] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0057] The purpose of this application is to provide an evaporative low-temperature refrigeration device and control method, which can be applied to the operation of low-temperature cold storage. This evaporative low-temperature refrigeration device forms a refrigerant cycle through a compressor, oil separator, evaporative condenser, economizer, economizer solenoid valve, and indoor terminal components. Furthermore, the use of economizer gas replenishment circulation improves the efficiency of the single-stage screw compressor refrigeration cycle, increases cooling capacity, and reduces compressor discharge temperature. In addition, when the indoor terminal components require defrosting, the defrosting water pump is activated, and the corresponding water circuit solenoid valve is opened, delivering the higher-temperature water from the evaporative condenser's water tank to the corresponding air cooler. The defrosted and cooled water can return to the evaporative condenser's water tank for refrigeration circulation, reducing the condensing temperature of the refrigeration system and lowering the operating power consumption of the refrigeration unit. It can also recover the cold energy from defrosting, improving refrigeration performance while increasing defrosting efficiency and reducing temperature fluctuations in the cold storage. Therefore, this evaporative low-temperature refrigeration device can reduce temperature fluctuations in the cold storage and achieve the technical effect of improving the defrosting efficiency of the low-temperature cold storage.

[0058] Please see Figures 1 to 3 , Figure 1 This is a schematic diagram of the structure of the evaporative cryogenic freezing device provided in the embodiments of this application. Figure 2 This is a schematic diagram of the evaporative condensation mechanism provided in the embodiments of this application. Figure 3 The present application provides a schematic diagram of an indoor terminal mechanism and a pre-set cold storage unit; wherein, the evaporative low-temperature refrigeration device includes a compressor 1, an oil separator 2, an evaporative condensing mechanism 3, an economizer 6, an economizer solenoid valve 7, and an indoor terminal assembly.

[0059] For example, compressor 1, oil separator 2, evaporative condenser 3, economizer 6, and economizer solenoid valve 7 are connected in sequence. Economizer 6 is connected to compressor 1 and indoor terminal assembly respectively. Indoor terminal assembly is connected to compressor 1. The refrigerant circulation is as follows: compressor 1, oil separator 2, evaporative condenser 3, economizer 6, economizer solenoid valve 7, and compressor 1 in sequence, or refrigerant circulation is as follows: compressor 1, oil separator 2, evaporative condenser 3, economizer 6, indoor terminal assembly, and compressor 1 in sequence.

[0060] For example, such as Figure 1As shown, the economizer 6 has four ports; when the economizer solenoid valve 7 is opened, part of the refrigerant circulation process is: compressor 1 → oil separator 2 → evaporative condenser 3 → economizer 6 → economizer solenoid valve 7 → economizer 6 → compressor 1, and the other part of the refrigerant circulation process is: compressor 1 → oil separator 2 → evaporative condenser 3 → economizer 6 → indoor terminal assembly → compressor 1.

[0061] When the economizer solenoid valve 7 is not turned on, the refrigerant circulation process is as follows: compressor 1 → oil separator 2 → evaporative condenser 3 → economizer 6 → indoor terminal unit → compressor 1.

[0062] For example, when the economizer solenoid valve 7 is opened, after the refrigerant passes through the economizer 6, a portion of it returns to the economizer 6 through the economizer solenoid valve 7 and then back to the compressor 1; thus, the economizer gas replenishment cycle can improve the efficiency of the single-stage screw compressor refrigeration cycle, increase the cooling capacity, and reduce the compressor discharge temperature.

[0063] For example, the evaporative condensation mechanism 3 includes a water tank 35 and a defrosting water pump 37. The indoor terminal assembly includes at least one indoor terminal mechanism 9. Each indoor terminal mechanism 9 is installed in a pre-set cold storage. The indoor terminal mechanism 9 includes a cold air blower 91 and a water circuit solenoid valve 97. The water tank 35, the defrosting water pump 37, and the water circuit solenoid valve 97 are connected in sequence. The water in the water tank 35 is transported to the corresponding cold air blower 91 for defrosting through the defrosting water pump 37 and the water circuit solenoid valve 97.

[0064] Optionally, after the water in the water tank 35 is delivered to the corresponding air cooler 91 for defrosting, the water can be recycled back into the water tank 35 to form a water cycle.

[0065] In some embodiments, the evaporative low-temperature refrigeration unit forms a refrigerant cycle through the compressor 1, oil separator 2, evaporative condenser 3, economizer 6, economizer solenoid valve 7, and indoor terminal components. Furthermore, the use of economizer 6 for gas replenishment improves the efficiency of the single-stage screw compressor refrigeration cycle, increases cooling capacity, and reduces compressor discharge temperature. Additionally, when the indoor terminal component 9 requires defrosting, the defrosting water pump 37 is activated, and the corresponding water circuit solenoid valve 97 is opened. This delivers the warmer water from the water tank 35 of the evaporative condenser 3 to the corresponding air cooler 91. The defrosted and cooled water returns to the water tank 35 of the evaporative condenser 3 for refrigeration cycle, reducing the condensing temperature of the refrigeration system and lowering the operating power consumption of the refrigeration unit. It also recovers the cooling energy from defrosting, improving refrigeration performance while increasing defrosting efficiency and reducing temperature fluctuations in the cold storage. Therefore, this evaporative low-temperature refrigeration unit can reduce temperature fluctuations in the cold storage, achieving the technical effect of improving the defrosting efficiency of the low-temperature cold storage.

[0066] For example, the evaporative low-temperature refrigeration device also includes multiple temperature and humidity sensors 15. The preset cold storage is equipped with a return air door 11, a fresh air door 10, a defrost door 12, and an air outlet door 13. The preset cold storage is ventilated through an air duct. The multiple temperature and humidity sensors 15 are respectively installed at the air outlet, the return air outlet, and the outdoor area of ​​the preset cold storage.

[0067] For example, by introducing the preset temperature and humidity of the cold storage's exhaust air, return air, and the outside, and then considering the moisture content of the fresh air and the goods, the amount of frost at the current stage can be calculated. This can more effectively determine the conditions for defrosting, thereby avoiding the problem of inaccurate defrosting conditions leading to untimely or frequent defrosting, and solving the problems of consuming a lot of electricity on defrosting and large temperature fluctuations in the warehouse.

[0068] For example, the evaporative low-temperature refrigeration device also includes a purification and disinfection mechanism 14, with the return air door 11 and the fresh air door 10 facing each other, the defrost door 12 and the air outlet door 13 facing each other, and the air cooler 91 disposed between the return air door 11 and the air outlet door 13. The purification and disinfection mechanism 14 is matched and installed with the air cooler.

[0069] For example, the air passes through the purification and disinfection unit 14 and the air cooler 91 for disinfection and cooling before entering the preset cold storage, ensuring that the air entering the preset cold storage meets the temperature and cleanliness requirements.

[0070] In some implementations, when defrosting is not required, the refrigeration operates normally, with the return air door 11 and the outlet air door 13 open, and the fresh air door 10 and the defrosting door 12 closed. The air enters the cold storage after being disinfected and cooled by the purification and disinfection device 14 and the air cooler 91.

[0071] For example, the evaporative cryogenic refrigeration device also includes an expansion valve 8, which is connected to an economizer 6 and an economizer solenoid valve 7.

[0072] For example, the evaporative cryogenic refrigeration device also includes a liquid receiver 4 and a dryer filter 5, and the evaporative condenser 3, the liquid receiver 4, the dryer filter 5, and the economizer 6 are connected in sequence.

[0073] For example, the evaporative condensing mechanism 3 also includes a fan 31, a water distributor 32, a plate-tube condenser 33, a packing 34, and a water pump 36. The fan 31, water distributor 32, plate-tube condenser 33, packing 34, and water tank 35 are stacked sequentially from top to bottom. The water pump 36 is connected to the water distributor 32 and the water tank 35 respectively. The air cooler 91 is connected to the water tank 35, and the water from the air cooler 91 after defrosting is recycled to the water tank 35.

[0074] For example, by pumping water 36 to deliver water from water tank 35 to water distributor 32, water drips sequentially from water distributor 32, plate-tube condenser 33, and packing 34, and is then returned to water tank 35, and air flow efficiency is increased by fan 31.

[0075] For example, the types of pre-set cold storage include high-temperature cold storage and low-temperature cold storage;

[0076] When the indoor terminal mechanism 9 is installed in a high-temperature freezer, the indoor terminal mechanism 9 also includes an evaporation pressure regulating valve 93, which is connected to the air cooler 91 and the compressor 1 respectively.

[0077] When the indoor terminal mechanism 9 is installed in a low-temperature freezer, the indoor terminal mechanism 9 also includes a one-way valve 96, which is connected to the air cooler 91 and the compressor 1 respectively.

[0078] For example, depending on the preset operating temperature of the cold storage, the evaporation pressure regulating valve 93 and the one-way valve 96 are installed differently to ensure the refrigeration efficiency of the preset cold storage.

[0079] Optionally, a high-temperature freezer can be a 0°C preservation warehouse, etc.; a low-temperature freezer can be a -18°C cold storage warehouse, a -35°C quick-freezing warehouse, etc.

[0080] For example, the indoor terminal mechanism 9 also includes a thermal expansion valve 92, which is connected to the economizer 6 and the air cooler 91 respectively.

[0081] For example, the indoor terminal mechanism 9 also includes a dryer filter 94 and a solenoid valve 95, with the thermal expansion valve 92, dryer filter 94, solenoid valve 95 and air cooler 91 connected in sequence.

[0082] For example, the evaporative cryogenic refrigeration device also includes a gas-liquid separator 61, which is connected to a cooler 91 and a compressor 1.

[0083] In some implementation scenarios, combined with Figures 1 to 3 The evaporative cryogenic refrigeration device provided in this application embodiment has the following refrigerant flow: the refrigerant passes through the compressor 1 and becomes a high-temperature, high-pressure refrigerant gas, then enters the oil separator 2. The separated oil returns to the compressor 1. The refrigerant then enters the evaporative condensing mechanism 3 and condenses into a medium-temperature, high-pressure refrigerant liquid, which enters the receiver 4, passes through the dryer filter 5, and enters the economizer 6. It then splits into two parts: one part passes through the expansion valve 8 and the economizer solenoid valve 7 to enter the economizer 6, and then returns to the compressor 1; the other part enters the indoor terminal mechanism 9, passes through the dryer filter 94, the solenoid valve 95, the thermal expansion valve 92, and the air cooler 91 to absorb heat and evaporate, and then passes through the evaporative pressure regulating valve 93 or the one-way valve 96 to enter the gas-liquid separator 61 and return to the compressor 1.

[0084] The defrosting water flow is as follows: when the indoor terminal mechanism 9 has a defrosting requirement, the defrosting water pump 37 is turned on and the corresponding water circuit solenoid valve 97 is opened, so that the water with a higher temperature in the water tank 35 of the evaporative condenser mechanism 3 is delivered to the corresponding air cooler 91. The water cooled by defrosting is then returned to the evaporative condenser mechanism 3 for refrigeration cycle, which can reduce the condensing temperature of the refrigeration system and reduce the operating power consumption of the refrigeration unit.

[0085] Please see Figure 4 , Figure 4 This is a flowchart illustrating a control method for evaporative cryogenic freezing provided in an embodiment of this application. This evaporative cryogenic freezing control method is applied to... Figures 1 to 3 The evaporative cryogenic freezing apparatus shown includes the following steps:

[0086] The operating time of the evaporative low-temperature refrigeration unit, as well as the cold storage door opening time, inlet air humidity, outlet air humidity, and ambient humidity of the preset cold storage are obtained.

[0087] S110: Calculate the cumulative frost amount based on the first preset formula, running time, cold storage door opening time, inlet air humidity, outlet air humidity, and ambient humidity.

[0088] S120: If the cumulative frost amount exceeds the frost amount threshold, then perform defrosting on the evaporative low-temperature refrigeration unit.

[0089] S130: Turn off the air cooler and turn on the defrosting water pump and water circuit solenoid valve within the preset defrosting time. The preset defrosting time is determined based on the second preset formula, the cumulative amount of frost, the preset temperature of the cold storage, the flow rate of the defrosting water, and the temperature difference between the inlet and outlet of the defrosting water.

[0090] S140: After the defrosting process is completed, control the air cooler to start for a preset time;

[0091] S150: Controls the operation of the evaporative cryogenic refrigeration unit in a preset refrigeration mode.

[0092] For example, by incorporating the cold storage door opening time, as well as the humidity of the incoming air, the humidity of the outgoing air, and the ambient humidity, the current cumulative frost amount can be calculated. Combined with the set frost amount threshold, the conditions for entering defrost can be determined more effectively. Moreover, by quantitatively calculating the heat required for the cumulative frost to melt into water, and calculating and obtaining the heat that can be provided during defrost according to the second preset formula, the duration of defrost can be precisely controlled, avoiding excessive defrosting or incomplete defrosting, thus improving defrost efficiency.

[0093] For example, the first preset formula is:

[0094] M=q×(di-do)×(T-t1)+q×(a×(dh-do)+(1-a)×(di-do))×t1;

[0095] Where M is the cumulative frost amount, t1 is the cold storage door opening time, T is the running time, di is the inlet air humidity, do is the outlet air humidity, dh is the ambient humidity, q is the air volume of the air cooler, and a is the preset coefficient.

[0096] The second preset formula is:

[0097] t2=(M×C×△t1+M×r)÷(G×1.163×△t2);

[0098] Where t2 is the preset defrosting time, C is the specific heat capacity of ice, r is the heat of fusion of ice, Δt1 is the temperature difference between the preset cold storage and 0℃, G is the defrosting water flow rate, and Δt2 is the temperature difference between the inlet and outlet of the defrosting water.

[0099] Optionally, by setting a return air door, a fresh air door, a defrost door, and an outlet air door, the return air door 11 and outlet air door 13 of the preset cold storage can be closed during defrosting, while the fresh air door 10 and the defrost door 12 can be opened, and the fan of the air cooler 91 can be turned on to introduce fresh air, which can quickly blow away or evaporate the water droplets on the fin surface, thereby shortening the entire defrosting time.

[0100] Please see Figure 5 , Figure 5 This is a schematic flowchart of another evaporative cryogenic freezing control method provided in an embodiment of this application. This evaporative cryogenic freezing control method is applied to... Figures 1 to 3 The control method for the evaporative cryogenic refrigeration device shown includes the following steps:

[0101] S210: Acquire information on the opening status of the economizer solenoid valve, the compressor discharge temperature data, and the compressor load data;

[0102] S220: Determine whether the economizer solenoid valve is in the open state based on the opening status information;

[0103] S230: If the economizer solenoid valve is in the open state, the economizer solenoid valve will be closed when the exhaust temperature data is less than the first opening exhaust temperature threshold or the compressor load data is less than the load threshold.

[0104] S240: If the economizer solenoid valve is closed, the economizer solenoid valve will be opened when the exhaust temperature data is greater than or equal to the second opening exhaust temperature threshold or the compressor load data is greater than the load threshold.

[0105] For example, by setting an economizer and controlling the economizer solenoid valve according to the exhaust temperature data and compressor load, the efficiency of the single-stage screw compressor refrigeration cycle can be improved, the refrigeration capacity can be increased, and the compressor exhaust temperature can be reduced.

[0106] In some implementation scenarios, combined with Figures 1 to 5The control method for evaporative cryogenic freezing provided in this application embodiment has the following general control method example:

[0107] 1. Economizer solenoid valve control:

[0108] Using an economizer supplementary gas cycle can improve the efficiency of a single-stage screw compressor refrigeration cycle, increase cooling capacity, and reduce compressor discharge temperature. However, it is necessary to select appropriate start-up conditions. When the discharge temperature and load are low, starting the economizer will not increase the cooling capacity, but will increase power consumption and decrease the unit's COP.

[0109] (1) It will be turned on when the exhaust temperature is ≥ Tps (80℃) or the compressor load is ≥ 75%.

[0110] (2) When the exhaust temperature is <Tpc (50℃) or the compressor load is <75%, the compressor will shut down.

[0111] 2. Defrosting control:

[0112] 2.1 Determining defrost:

[0113] (1) Record the cold storage door opening time t1, air supply and return, and outdoor temperature and humidity in real time;

[0114] (2) Calculate the moisture content of the incoming air (di), the moisture content of the outgoing air (do), and the ambient moisture content (dh) by taking in the air intake and return, and the outdoor temperature and humidity.

[0115] (3) Calculate the cumulative frost amount based on the moisture content difference, running time T, and air volume q of the evaporative cooler. When the door is opened, take the fresh air entering the warehouse as 15% of the evaporative cooler's air volume (preset coefficient, this value can be adjusted):

[0116] M=q×(di-do)×(T-t1)+q×(0.15×(dh-do)+0.85×(di-do))×t1;

[0117] (4) Compare the cumulative frost amount M with the set frost amount Ms (frost amount threshold). If M > Ms for 1 minute, then proceed to defrost.

[0118] 2.2 Defrosting Action:

[0119] (1) Close the solenoid valve 95 and the air cooler 91 of the corresponding indoor terminal mechanism 9, and turn on the defrosting water pump 37 and the water circuit solenoid valve 97 of the corresponding terminal; close the return air door 11 and the air outlet door 13, and open the fresh air door 10 and the defrosting door 12.

[0120] (2) Determining the defrosting operation time t2 (preset defrosting time): Calculate the heat required to melt the frost into water based on the cumulative frost amount and Δt1 (difference between the storage temperature and 0℃), and calculate the heat provided by the defrosting water using the defrosting water flow rate G and the inlet and outlet temperature difference Δt2.

[0121] t2=(M×C×△t1+M×r)÷(G×1.163×△t2);

[0122] (3) After defrosting is completed, the defrosting water pump 37 and the corresponding end water circuit solenoid valve 97 are turned off. Since there are water droplets on the surface of the fins of the air cooler 91, in order to avoid frost forming again when the refrigeration unit is turned on, the fan on the air cooler 91 is turned on. The air enters from the fresh air door 10, evaporates and blows away the water droplets on the surface of the fins, and the air goes out from the defrost door 12 for 3 minutes.

[0123] (4) The defrosting process ends when the defrosting preset time t2 is added and the fan on the air cooler 91 is turned on for 3 minutes. Then the normal cooling mode is entered: the return air door 11, the outlet air door 13, the solenoid valve 95, the air cooler 91, and the compressor 1 are turned on, and the fresh air door 10 and the defrosting door 12 are turned off.

[0124] By way of example, the evaporative cryogenic freezing apparatus and control method provided in the embodiments of this application have at least the following beneficial effects:

[0125] 1. Using the cooling water of the evaporator-condenser as defrosting water, the defrosting water is cooled and then returned to the evaporator-condenser, which can recover the cold energy of defrosting, further reduce the condensing temperature of the refrigeration system, and improve the refrigeration performance.

[0126] 2. By taking into account the opening time of the cold storage door, the air supply and return, and the outdoor temperature and humidity, the current cumulative frost amount is calculated to scientifically determine the conditions for entering the defrosting stage;

[0127] 3. By quantitatively calculating the heat required for the accumulated frost to melt into water, and analyzing the heat that can be provided during defrosting, the defrosting time can be precisely controlled, eliminating the possibility of excessive or incomplete defrosting.

[0128] 4. The system is equipped with return air door, fresh air door, defrost door, and air outlet door. Close the return air door and air outlet door of the warehouse, turn on the fan of the air cooler to introduce fresh air, quickly blow away or evaporate the water droplets on the fin surface, and shorten the entire defrost time.

[0129] 5. By setting up an economizer and providing a reliable economizer operation control scheme, the efficiency of the single-stage screw compressor refrigeration cycle is improved, the refrigeration capacity is increased, and the compressor discharge temperature is reduced;

[0130] 6. Set up an independent cavity in the cold storage to house the air cooler, and install a purification and disinfection device according to the purification requirements to meet the cleanliness requirements of the pharmaceutical industry for the warehouse.

[0131] In all embodiments of this application, "large" and "small" are relative terms, "more" and "less" are relative terms, and "upper" and "lower" are relative terms. The embodiments of this application will not elaborate further on the expression of such relative terms.

[0132] It should be understood that the phrases "in this embodiment," "in this application embodiment," or "as an optional implementation" throughout the specification mean that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, the phrases "in this embodiment," "in this application embodiment," or "as an optional implementation" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this application.

[0133] In the various embodiments of this application, it should be understood that the sequence number of each process does not necessarily imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0134] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

Claims

1. A control method for evaporative cryogenic freezing, characterized in that, It is applied to an evaporative cryogenic refrigeration unit, which includes a compressor, an oil separator, an evaporative condenser mechanism, an economizer, an economizer solenoid valve, and an indoor terminal assembly; The compressor, the oil separator, the evaporative condenser, the economizer, and the economizer solenoid valve are connected in sequence. The economizer is connected to the compressor and the indoor terminal assembly, respectively. The indoor terminal assembly is connected to the compressor. The refrigerant circulation is either sequentially through the compressor, the oil separator, the evaporative condenser, the economizer, the economizer solenoid valve, and the compressor, or sequentially through the compressor, the oil separator, the evaporative condenser, the economizer, the indoor terminal assembly, and the compressor. The evaporative condensation mechanism includes a water tank and a defrosting water pump. The indoor terminal assembly includes at least one indoor terminal mechanism. Each indoor terminal mechanism is installed in a pre-set cold storage. The indoor terminal mechanism includes a cold air blower and a water circuit solenoid valve. The water tank, the defrosting water pump, and the water circuit solenoid valve are connected in sequence. The water in the water tank is transported to the corresponding cold air blower for defrosting through the defrosting water pump and the water circuit solenoid valve. The control method includes: The operating time of the evaporative low-temperature refrigeration device, as well as the cold storage door opening time, inlet air humidity, outlet air humidity, and ambient humidity of the preset cold storage are obtained. The cumulative frost amount is calculated based on the first preset formula, the running time, the cold storage door opening time, the inlet air humidity, the outlet air humidity, and the ambient humidity. If the cumulative frost amount exceeds the frost amount threshold, then the evaporative low-temperature freezing device is subjected to defrosting treatment: The air cooler is turned off within a preset defrosting time, and the defrosting water pump and the water circuit solenoid valve are turned on. The preset defrosting time is determined based on a second preset formula, the cumulative amount of frost, the preset temperature of the cold storage, the flow rate of the defrosting water, and the temperature difference between the inlet and outlet of the defrosting water. After the defrosting process is completed, the air cooler is turned on for a preset time. The evaporative cryogenic refrigeration device is controlled to operate in a preset refrigeration mode; The first preset formula is: M=q×(di-do)×(T-t1)+q×(a×(dh-do)+(1-a)×(di-do))×t1; Where M is the cumulative frost amount, t1 is the cold storage door opening time, T is the running time, di is the inlet air humidity, do is the outlet air humidity, dh is the ambient humidity, q is the air volume of the air cooler, and a is a preset coefficient. The second preset formula is: t2= (M×C×△t1+ M×r)÷(G×1.163×△t2); Wherein, t2 is the preset defrosting time, C is the specific heat capacity of ice, r is the heat of fusion of ice, Δt1 is the temperature difference between the preset cold storage and 0℃, G is the defrosting water flow rate, and Δt2 is the temperature difference between the inlet and outlet of the defrosting water.

2. The control method for evaporative cryogenic freezing according to claim 1, characterized in that, The device also includes multiple temperature and humidity sensors. The preset cold storage is equipped with a return air door, a fresh air door, a defrost door, and an air outlet door. The preset cold storage is ventilated through an air duct. The multiple temperature and humidity sensors are respectively installed at the air outlet, the return air outlet, and the outdoor area of ​​the preset cold storage.

3. The control method for evaporative cryogenic freezing according to claim 2, characterized in that, The device also includes a purification and disinfection mechanism, with the return air door and the fresh air door facing each other, the defrosting door and the air outlet door facing each other, and the air cooler disposed between the return air door and the air outlet door. The purification and disinfection mechanism is matched and installed with the air cooler.

4. The control method for evaporative cryogenic freezing according to claim 1, characterized in that, The device also includes an expansion valve, which is connected to the economizer and the economizer solenoid valve.

5. The control method for evaporative cryogenic freezing according to claim 1, characterized in that, The device also includes a liquid reservoir and a drying filter, and the evaporative condenser, the liquid reservoir, the drying filter, and the economizer are connected in sequence.

6. The control method for evaporative cryogenic freezing according to claim 1, characterized in that, The evaporative condensation mechanism also includes a fan, a water distributor, a plate-tube condenser, packing material, and a water pump. From top to bottom, the fan, the water distributor, the plate-tube condenser, the packing material, and the water tank are stacked in sequence, and the water pump is connected to the water distributor and the water tank respectively. The air cooler is connected to the water tank, and the water from the defrost operation of the air cooler is recycled back to the water tank.

7. The control method for evaporative cryogenic freezing according to claim 1, characterized in that, The types of the pre-designated cold storage include high-temperature cold storage and low-temperature cold storage; When the indoor terminal mechanism is installed in the high-temperature freezer, the indoor terminal mechanism also includes an evaporation pressure regulating valve, which is connected to the air cooler and the compressor respectively. When the indoor terminal mechanism is installed in the low-temperature freezer, the indoor terminal mechanism also includes a one-way valve, which is connected to the air cooler and the compressor respectively.

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