Cold storage refrigeration energy-saving optimization device based on food freezing process
By designing a refrigeration energy-saving optimization device based on the food freezing process in the cold storage, and using sensors and central controllers for real-time dynamic adjustment, the problems of large energy consumption and poor freezing quality during the freezing process of the cold storage are solved, and efficient energy-saving and high-quality freezing effects are achieved.
Patent Information
- Application Number
- CN202420724977.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-10
- Publication Date
- 2025-03-14
- Estimated Expiration
- 2034-04-10
AI Technical Summary
The existing cold storage consumes a lot of energy during the freezing process and the freezing quality is poor. The existing energy-saving optimization research has not fully considered the different temperature requirements during the food freezing process, and the static optimization method is not suitable for intermittent freezing processes.
A refrigeration energy-saving optimization device for cold storage based on the food freezing process is designed, including a warehouse temperature sensor, meat temperature sensor, temperature supply sensor, return temperature sensor, central controller, refrigerator and evaporator. By dynamically adjusting the evaporator superheat, refrigerator air volume and cold storage temperature in real time, fine control of the freezing process is achieved.
By adjusting the cold storage temperature and air volume of the refrigerator in stages, the freezing quality is improved, and the efficient and energy-saving operation of the cold storage is achieved through dynamic adjustment, and the cold storage status can be monitored remotely in real time.
Smart Images
Figure CN222617350U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of motor control, in particular to a cold storage refrigeration energy-saving optimization device based on a food freezing process. Background Art
[0002] In recent years, with the increasing demand for frozen and refrigerated foods, the rapid development of the cold storage industry has also brought about the problem of increasing cold storage energy consumption. Therefore, research on cold storage refrigeration energy saving has become increasingly important. The food processing process in the cold storage includes cooling, refrigeration and freezing. Different food processing processes have different characteristics and process requirements. However, most of the existing cold storage energy-saving optimization research is simply based on the perspective of the cold storage power system, and does not fully consider the temperature requirements at different stages of the food processing process. In addition, most of the existing studies use static optimization methods, which are suitable for continuous processes such as food refrigeration, but not for intermittent processes such as food freezing and cooling.
[0003] Forced air circulation is often used in cold storage to cool and freeze food. Changes in air parameters such as air temperature, flow rate, and turbulence intensity will affect the heat and mass exchange between cold air and food, and thus affect the quality of food freezing. By controlling the evaporation temperature of the refrigeration system and the air volume of the air cooler, the air temperature and air flow rate in the freezing room can be controlled, and then the freezing conditions of the food in the freezing room can be adjusted, thereby achieving the purpose of controlling the food freezing process. In the operation of traditional cold storage, the freezing process maintains the maximum air volume, the air cooler does not perform frequency conversion adjustment, and the evaporation temperature is kept in a small range through the loading and unloading of the compressor, resulting in low refrigeration efficiency and high energy consumption. Utility Model Content
[0004] The embodiment of the utility model provides a cold storage refrigeration energy-saving optimization device based on the food freezing process to solve the above technical problems.
[0005] In order to solve the above technical problems, the embodiment of the utility model proposes a cold storage refrigeration energy-saving optimization device based on the food freezing process, including: a storage temperature sensor, a meat temperature sensor, a supply temperature sensor, a return temperature sensor, a central controller, a refrigerator, and an evaporator; wherein: the storage temperature sensor is used to measure the temperature of the cold storage; the meat temperature sensor is used to measure the temperature change of food; the supply temperature sensor is used to measure the liquid supply temperature entering the evaporator; the return temperature sensor is used to measure the return air temperature of the evaporator; all sensors are connected to the central controller; the central controller is used to receive signals from each sensor and then perform real-time dynamic regulation on the evaporator superheat, refrigerator air volume and storage temperature of the cold storage.
[0006] Furthermore, the evaporator includes an evaporator liquid supply pipe, and the liquid supply pipe is provided with an electronic expansion valve, and the electronic expansion valve adjusts the liquid supply flow of the evaporator according to the superheat of the evaporator through PID control.
[0007] Furthermore, the central controller dynamically adjusts the cold storage temperature and the refrigeration machine air volume in sections according to the comparison between the storage temperature set values and the actual measured values in different freezing stages.
[0008] Furthermore, the energy-saving optimization device also includes: an RS-485 interface, a storage temperature display board and a smart meter; the central processor is connected to the storage temperature display board and the smart meter via the RS-485 interface to monitor the storage temperature and power consumption of the cold storage in real time.
[0009] Furthermore, the energy-saving optimization device also includes a network communication box; the central controller is connected to the network communication box.
[0010] The beneficial effects of the embodiments provided by the utility model are as follows: the beneficial effects of the embodiments provided by the utility model are as follows: the temperature setting value of the cold storage is adjusted in stages according to the food freezing process, so as to improve the food freezing quality in the intermittent freezing process; dynamic adjustment is performed according to the storage temperature, the superheat degree of the refrigerator and the air supply volume, and the freezing process is controlled in real time to make the cold storage run efficiently and energy-saving; the cold storage can be remotely monitored in real time through intelligent devices such as communication interfaces. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is a schematic diagram of a framework of a cold storage refrigeration energy-saving optimization device based on a food freezing process according to an embodiment of the utility model.
[0012] Figure 2 It is a schematic diagram of temperature control of a cold storage refrigeration energy-saving optimization device based on a food freezing process according to an embodiment of the utility model.
[0013] Description of Figure Numbers
[0014] 1. Warehouse temperature sensor; 2. Meat temperature sensor; 3. Supply temperature sensor; 4. Outlet temperature sensor; 5. Evaporator; 6. Central controller; 7. Smart electric meter; 8. Warehouse temperature dashboard; 9. Food. DETAILED DESCRIPTION
[0015] It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present utility model is further described in detail below in conjunction with the drawings and specific embodiments.
[0016] In the embodiments of the present invention, if there are directional indications (such as up, down, left, right, front, back, etc.), they are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0017] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.
[0018] Please refer to Figure 1 The utility model provides a cold storage refrigeration energy-saving optimization device based on the food freezing process, comprising a storage temperature sensor, a meat temperature sensor, a supply temperature sensor, a return temperature sensor, a central controller, a refrigerator, and an evaporator; wherein: the storage temperature sensor is used to measure the temperature of the cold storage; the meat temperature sensor is used to measure the temperature change of food; the supply temperature sensor is used to measure the liquid supply temperature entering the evaporator; the return temperature sensor is used to measure the return air temperature of the evaporator; all sensors are connected to the central controller; the central controller is used to receive signals from each sensor and then perform real-time dynamic regulation on the evaporator superheat, refrigerator air volume and storage temperature of the cold storage.
[0019] Furthermore, the evaporator includes an evaporator liquid supply pipe, and the liquid supply pipe is provided with an electronic expansion valve, and the electronic expansion valve is controlled according to the superheat of the evaporator PID, thereby adjusting the liquid supply flow of the evaporator to prevent the liquid refrigerant that is not completely evaporated from the evaporator from entering the compressor and affecting the operation of the system. Exemplarily, the superheat setting value is controlled by PID between 1 and 15°C according to the temperature difference between the evaporation temperature (i.e., the liquid supply temperature) and the storage temperature, and then the superheat is calculated according to the difference between the evaporator return air temperature and the liquid supply temperature; finally, the superheat calculation value is compared with the superheat setting value, and the PID controls the electronic expansion valve to adjust the liquid supply flow of the evaporator, and the refrigerant in the evaporator is ensured to be completely evaporated through superheat regulation, so as to prevent the liquid refrigerant from entering the compressor and affecting its normal operation.
[0020] Furthermore, the central controller dynamically adjusts the cold storage temperature and the air volume of the refrigeration machine in sections according to the comparison between the storage temperature set value and the actual measurement value in different freezing stages. Preferably, the dynamic adjustment of the storage temperature and the air supply volume by the central controller includes: judging the freezing stage of the food according to the food center temperature detected by the meat temperature sensor in the cold storage; determining the corresponding cold storage temperature set value according to the freezing stage of the food; comparing the actual storage temperature measurement value with the storage temperature set value to PID control the air volume of the cold air machine. Exemplarily, the superheat adjustment method of the cold storage refrigeration energy-saving optimization device based on the food freezing process in combination with the embodiment of the utility model may include: first, according to the temperature difference between the evaporation temperature (i.e., the liquid supply temperature) and the storage temperature, the superheat setting value is between 1 and 15 ° C; then, the superheat is calculated according to the difference between the evaporator return air temperature and the liquid supply temperature; and the calculated value of the superheat is compared with the superheat setting value to PID control the electronic expansion valve to adjust the liquid supply flow of the evaporator.
[0021] Furthermore, the energy-saving optimization device also includes: an RS-485 interface, a storage temperature display board and a smart meter; the central processor is connected to the storage temperature display board and the smart meter via the RS-485 interface to monitor the storage temperature and power consumption of the cold storage in real time.
[0022] Furthermore, the energy-saving optimization device also includes a network communication box; the central controller can also be connected to the network communication box to facilitate remote data transmission.
[0023] See also Figure 2 To better understand the embodiments of the present invention, the following is an exemplary description of the working of the embodiments of the present invention:
[0024] For example, firstly, the food is judged to be in the pre-cooling stage, phase change stage or super-cooling stage according to the meat center temperature detected by the meat temperature sensor in the cold storage, and the freezing stage of the food is used as the basis for segmented judgment of the cold storage temperature setting value. The cold storage temperature setting value in the pre-cooling stage decreases linearly with the freezing time, and the cold storage temperature setting value range is -10℃~-20℃. The cold storage temperature setting value in the phase change stage does not change with the freezing time and is a constant value of -30℃. The cold storage temperature setting value in the super-cooling stage increases linearly with the freezing time, and the cold storage setting temperature range is -20℃~-25℃. After confirming the cold storage temperature setting value, the air volume of the cold air blower is controlled by PID by comparing the actual storage temperature value measured by the storage temperature sensor with the storage temperature setting value. In this way, the dynamic adjustment of the cold storage temperature and the air volume of the refrigeration machine is realized, and the freezing process is controlled in real time, so that the cold storage maintains efficient and energy-saving operation.
[0025] The food freezing curve can be divided into three stages: precooling stage, phase change stage and supercooling stage. In the precooling stage, the sensible heat of the food is taken away by the low-temperature medium, and the center temperature of the food begins to drop from the initial state point. The food temperature drops to about 0~-1℃ after about 1.7 hours, and the food begins to freeze. The cold storage set temperature drops at a rate of 5.88℃ / h. The relationship between the cold storage temperature setting value and time t can be expressed as: ; Then part of the water in the food undergoes phase change and crystallizes, the food freezing process enters the phase change stage and releases a large amount of latent heat, the food temperature drops very slowly, and remains at around -1~-3℃, and the corresponding cold storage temperature setting value remains at a constant value of -30℃ until 6.7 hours later, the freezing process enters the supercooling stage, the food continues to release the remaining latent heat and food sensible heat to continue to reduce the food temperature until it reaches the freezing temperature (-3~-15℃). The temperature change trend of the food in the supercooling stage is similar to that in the precooling stage, but the cold storage temperature setting value increases at a rate of 3.13℃ / h, so that the cold storage meets the refrigeration demand while saving energy.
[0026] Exemplarily, the cold storage refrigeration energy-saving optimization device based on the food freezing process, the cold storage temperature setting value is designed in sections according to the food freezing curve, and can be divided into the pre-cooling stage, the phase change stage and the supercooling stage. Among them, the food temperature in the pre-cooling stage starts to drop from the initial state point to the initial freezing point temperature (0~-1°C), and the sensible heat in the food is taken away by the low-temperature medium, and the corresponding cold storage temperature setting value T decreases linearly. The cold storage temperature setting range in the pre-cooling stage is -10°C~-20°C, and the temperature drop rate is v1; in the phase change stage, the food moisture crystallizes and releases latent heat, and the food temperature slowly decreases (-1~-3°C), and the corresponding cold storage temperature setting value is a constant value of -30°C. In the supercooling stage, the food releases the remaining latent heat and the sensible heat of the food to continue to reduce the food temperature (-3~-15°C) until the freezing temperature is reached. The cold storage temperature setting range in the supercooling stage is -20°C~-25°C, and the temperature change rate is v2; the piecewise function of the cold storage temperature setting value changing with the freezing time t is:
[0027]
[0028] Among them, t1 and t2 are the initial freezing time and the supercooling start time respectively.
[0029] The cold storage refrigeration energy-saving optimization device based on the food freezing process determines the freezing stage of the food according to the central temperature of the meat detected by the meat temperature sensor, and uses it as a basis for segmented judgment of the cold storage temperature setting value, thereby dynamically adjusting the cold storage temperature and the air supply volume of the refrigerator.
[0030] The beneficial effects of the embodiments provided by the utility model are as follows: the temperature setting value of the cold storage is adjusted in stages according to the food freezing process, thereby improving the food freezing quality in the intermittent freezing process; dynamic adjustment is performed according to the storage temperature, the superheat of the refrigerator and the air supply volume, and the freezing process is controlled in real time, so that the cold storage can operate efficiently and energy-savingly; the cold storage can be remotely monitored in real time through intelligent devices such as communication interfaces.
[0031] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A cold storage refrigeration energy-saving optimization device based on the food freezing process, characterized in that: include: Warehouse temperature sensor, meat temperature sensor, supply temperature sensor, return temperature sensor, central controller, refrigerator, evaporator; among them: The storage temperature sensor is used to measure the temperature of the cold storage; the meat temperature sensor is used to measure the temperature change of food; the supply temperature sensor is used to measure the liquid supply temperature entering the evaporator; the return temperature sensor is used to measure the return air temperature of the evaporator; all sensors are connected to the central controller; the central controller is used to receive signals from each sensor and perform real-time dynamic regulation on the evaporator superheat, refrigerator air volume and storage temperature of the cold storage.
2. The energy-saving optimization device according to claim 1, characterized in that: The evaporator comprises an evaporator liquid supply pipe, on which an electronic expansion valve is arranged, and the electronic expansion valve adjusts the liquid supply flow of the evaporator according to the superheat degree of the evaporator through PID control.
3. The energy-saving optimization device according to claim 1, characterized in that: The central controller dynamically adjusts the cold storage temperature and the refrigeration machine air volume in sections according to the comparison between the storage temperature set values and the actual measured values in different freezing stages.
4. The energy-saving optimization device according to claim 1, characterized in that: The energy-saving optimization device also includes: an RS-485 interface, a storage temperature dashboard and an intelligent electric meter; the central controller is connected to the storage temperature dashboard and the intelligent electric meter via the RS-485 interface to monitor the storage temperature and power consumption of the cold storage in real time.
5. The energy-saving optimization device according to claim 1, characterized in that: The energy-saving optimization device also includes a network communication box; the central controller is connected to the network communication box.