A device and method for preventing wall icing based on online infrared temperature measurement technology

Abstract

A device and method for preventing wall icing based on online infrared temperature measurement technology belongs to the field of air conditioning and refrigeration technology. The device includes: a cold storage compartment containing refrigerated products; an online infrared thermometer installed on the inner top of the cold storage compartment to collect the surface temperature of the refrigerated products; and a refrigeration system for cooling the cold storage compartment. The method prevents wall icing by monitoring the surface temperature of the refrigerated products, the surface temperature at the evaporator outlet, and the surface temperature at the evaporator inlet. This non-contact measurement method ensures the preservation temperature of the refrigerated products while simultaneously solving the problem of wall icing.

Description

Technical Field

[0001] This invention relates to the field of air conditioning and refrigeration technology, and in particular to a device and method for preventing wall icing based on online infrared temperature measurement technology. Background Technology

[0002] With rapid economic development and rising living standards, the demand for fresh, high-quality refrigerated processed foods is increasing. In the air conditioning and refrigeration industry, problems frequently arise such as ice formation on cold wall surfaces, leading to abnormal temperature control of refrigerated foods, shortened shelf life, and increased equipment energy consumption. Controlling wall icing is one of the key issues in ensuring food safety.

[0003] Zang Runqing et al. from Tianjin University of Commerce published a paper titled "Experimental Study on Air Defrosting of Air Fans in Cold Storage Rooms" in the journal *Low Temperature and Superconductivity*. Through measurements of the air temperature in the return air zone of the air fan and the fin temperature of the air fan evaporator assembly, and with a storage temperature of 5°C, the air fan, while running continuously during the compressor shutdown phase, was able to largely remove the frost accumulated during the previous refrigeration process. When the refrigeration system operates regularly for 8 hours, the ice accumulated during the previous refrigeration process can be completely removed by sequentially closing the liquid supply solenoid valves of the defrosting air fan for 15 minutes, ensuring the storage room temperature is lowered. This method focuses on eliminating frost formation in the cold storage room, rather than preventing it from occurring in the first place. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a device and method for preventing wall icing based on online infrared temperature measurement technology. It solves the problem of icing on cold walls while ensuring the storage temperature of refrigerated processed products through a non-contact measurement method.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A device for preventing wall icing based on online infrared temperature measurement technology, comprising:

[0007] The cold storage room contains refrigerated processed products;

[0008] An online infrared thermometer, installed on the inner top of the cold storage compartment, is used to collect the surface temperature of refrigerated processed products; and

[0009] The refrigeration system is used to cool the cold storage compartment.

[0010] Furthermore, the refrigeration system includes an evaporator, an electronic expansion valve installed at the inlet end of the evaporator, and a compressor connected to the outlet end of the evaporator; a second thermocouple thermometer is provided on the outer surface of the inlet end of the evaporator for collecting the surface temperature of the inlet end of the evaporator; a first thermocouple thermometer is provided on the outer surface of the outlet end of the evaporator for collecting the surface temperature of the outlet end of the evaporator.

[0011] Furthermore, the anti-icing device for walls based on online infrared temperature measurement technology also includes a control system, which comprises a data acquisition instrument and a computer. The input terminals of the data acquisition instrument are connected to an online infrared thermometer, a first thermocouple thermometer, and a second thermocouple thermometer, respectively. The output terminal of the data acquisition instrument is connected to the input terminal of the computer, and is used to transmit the surface temperature of the refrigerated processed products, the surface temperature at the evaporator outlet, and the surface temperature at the evaporator inlet to the computer. The output terminal of the computer is connected to an electronic expansion valve and a compressor, respectively, and is used to control the opening degree of the electronic expansion valve and the opening and closing of the compressor.

[0012] Furthermore, the refrigerator compartment has a rectangular structure with external insulation, and a refrigeration structure layer is provided on one side of the refrigerator compartment, which is in contact with the cold surface of the refrigerator compartment.

[0013] Furthermore, the evaporator is fitted onto the surface of the cold side located on one side of the refrigeration structure layer.

[0014] Preferably, the online infrared thermometer is positioned at the center of the inner top of the cold storage compartment, so that the refrigerated products in the cold storage compartment are within the measurement range of the online infrared thermometer.

[0015] A method for preventing wall icing based on online infrared temperature measurement technology, employing the aforementioned device for preventing wall icing based on online infrared temperature measurement technology, includes the following steps:

[0016] S1: Measure the height and thickness of the refrigeration structure layer of the cold storage compartment and input the data into the computer;

[0017] S2: Place the refrigerated food in the cold storage compartment. Use an online infrared thermometer to measure the surface temperature of the refrigerated food and transmit the data to the computer via a data acquisition device. The computer then makes the following judgments:

[0018] (1) When the collected surface temperature value of the refrigerated processed product is lower than or equal to the preset temperature value, the compressor remains off;

[0019] (2) When the collected surface temperature value of the refrigerated processed product is higher than the preset temperature value, the computer controls the compressor to start; at the same time, the first thermocouple thermometer collects the surface temperature at the outlet end of the evaporator, and the second thermocouple thermometer collects the surface temperature at the inlet end of the evaporator, and both are transmitted to the computer through the data acquisition instrument. The computer makes the following judgment:

[0020] If T1 > T+1, the computer controls the compressor to remain on.

[0021] If T+1≥T1>T-1, the computer controls the compressor to remain on and controls the electronic expansion valve to reduce its opening.

[0022] If T1 ≤ T-1, the computer controls the compressor to shut down;

[0023] Where T1 is the average temperature of the evaporator outlet surface temperature and the evaporator inlet surface temperature, in °C; and T is the average temperature control threshold of the evaporator, in °C.

[0024] Furthermore, the average temperature control threshold T of the evaporator is calculated according to the following formula:

[0025]

[0026] In the formula, δ is the thickness of the refrigeration structure layer, m; θ0 is the preset temperature value, ℃; and H is the height of the refrigeration structure layer, m.

[0027] The beneficial effects of this invention are:

[0028] 1) This invention uses a non-contact measurement method, relying solely on directly measuring the surface temperature of refrigerated products, to control the start-up time of the compressor and the opening degree of the electronic expansion valve, thus ensuring the preservation temperature of refrigerated products while solving the problem of icing on the cold wall surface.

[0029] 2) The control parameters of this invention are simple, which saves the operating cost of the cold storage compartment, rationally plans the working time of the compressor, and reduces the failure rate of the compressor during long-term operation;

[0030] 3) This invention overcomes the problem that the traditional control of compressor start-up time depends entirely on the temperature value set by the thermostat in the refrigerator compartment and changes in the ambient temperature, which requires manual adjustment and improves the level of automation.

[0031] Other features and advantages of the present invention will be described in detail in part in the following detailed description. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a device for preventing wall icing based on online infrared temperature measurement technology provided in an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the structure of the refrigerator compartment provided in an embodiment of the present invention.

[0034] The reference numerals in the accompanying drawings include:

[0035] 1-Refrigerator compartment, 2-Online infrared thermometer, 3-Refrigerated processed products, 4-Electronic expansion valve, 5-First thermocouple thermometer, 6-Evaporator, 7-Data acquisition instrument, 8-Computer, 9-Compressor, 10-Second thermocouple thermometer, 11-Bottom surface, 12-Top surface, 13-First side surface, 14-Cold surface, 15-Refrigerator door, 16-Second side surface, 17-Refrigeration structural layer. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0037] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In order to solve the problems existing in the current technology, such as Figures 1 to 2 As shown, the present invention provides a device for preventing wall icing based on online infrared temperature measurement technology, comprising:

[0039] Cold storage room 1, which contains refrigerated processed products 3;

[0040] An online infrared thermometer 2, installed on the inner top of the cold storage compartment 1, is used to collect the surface temperature of the refrigerated processed products 3; and

[0041] The refrigeration system is used to cool down the cold storage compartment 1.

[0042] In this embodiment, the online infrared thermometer 2 is a CHEKON HW-01A. The online infrared thermometer 2 is set in the middle of the top surface 12 to record the surface temperature of the refrigerated processed product 3 in real time and send the collected temperature values ​​to the computer 8. The refrigerated processed product 3 is grapes stored in a (length × width × height) 240mm × 240mm × 210mm food storage box.

[0043] like Figure 1As shown, the refrigeration system includes an evaporator 6, an electronic expansion valve 4 installed at the inlet end of the evaporator 6, and a compressor 9 connected to the outlet end of the evaporator 6; a second thermocouple thermometer 10 is provided on the outer surface of the inlet end of the evaporator 6 to collect the surface temperature of the inlet end of the evaporator 6; a first thermocouple thermometer 5 is provided on the outer surface of the outlet end of the evaporator 6 to collect the surface temperature of the outlet end of the evaporator 6.

[0044] In this embodiment, the evaporator 6 uses an 8mm copper tube; the electronic expansion valve 4 uses a DDF304 type electronic expansion valve; the compressor 9 uses an SC21CL type fully enclosed type; and the first thermocouple thermometer 5 and the second thermocouple thermometer 10 both use J-type thermocouples.

[0045] The present invention provides a device for preventing wall icing based on online infrared temperature measurement technology, which also includes a control system. The control system comprises a data acquisition unit 7 and a computer 8. The input terminals of the data acquisition unit 7 are connected to the online infrared thermometer 2, the first thermocouple thermometer 5, and the second thermocouple thermometer 10, respectively. The output terminal of the data acquisition unit 7 is connected to the input terminal of the computer 8, for transmitting the surface temperature of the refrigerated processed product 3, the surface temperature at the outlet of the evaporator 6, and the surface temperature at the inlet of the evaporator 6 to the computer 8. The output terminals of the computer 8 are connected to the electronic expansion valve 4 and the compressor 9, respectively, for controlling the opening degree of the electronic expansion valve 4 and the opening and closing of the compressor 9. Specifically, the input terminals of the data acquisition unit 7 are connected to the output terminals of the online infrared thermometer 2, the first thermocouple thermometer 5, and the second thermocouple thermometer 10, respectively.

[0046] In this embodiment, the data acquisition instrument 7 is a Fluke F2645A. The evaporator 6 is fitted onto the surface of the cold surface 14 located on one side of the refrigeration structure layer 17.

[0047] like Figure 2 As shown, the refrigerator compartment 1 has a rectangular structure with external insulation. A refrigeration structure layer 17 is provided on one side of the refrigerator compartment 1, and the refrigeration structure layer 17 is attached to the cold surface 14 of the refrigerator compartment 1. In this embodiment, the refrigerator compartment 1 is a closed space composed of a bottom surface 11, a top surface 12, a first side surface 13, a cold surface 14, a refrigerator door 15, and a second side surface 16. Polyurethane foam is filled between the refrigerator compartment 1 and the external cabinet structure for insulation. The internal space of the refrigerator compartment 1 is 833mm × 666mm × 470mm (length × width × height). The cold surface 14 is pressed together to reduce the gap with the evaporator 6, and the evaporator 6 is attached to the surface of the cold surface 14.

[0048] In a preferred embodiment, the online infrared thermometer 2 is positioned at the center of the inner top of the refrigerator compartment 1, so that the refrigerated processed products 3 in the refrigerator compartment 1 are within the measurement range of the online infrared thermometer 2. Specifically, the online infrared thermometer 2 is positioned in the middle of the top surface 12 of the refrigerator compartment 1, and the refrigerated processed products 3 are placed on the bottom surface 11, so that the entire space of the refrigerator compartment 1 is within the measurement range of the online infrared thermometer 2.

[0049] This invention also provides a method for preventing wall icing based on online infrared temperature measurement technology. The method employs the aforementioned device for preventing wall icing based on online infrared temperature measurement technology, and includes the following steps:

[0050] S1: Measure the height and thickness of the refrigeration structure layer 17 of the cold storage compartment 1 and input them into the computer 8; In this embodiment, the height of the refrigeration structure layer 17 is the height of the cold surface 14 of the cold storage compartment 1, which is 470mm and the thickness of the refrigeration structure layer 17 is 10mm.

[0051] S2: At room temperature of 20℃, the refrigerated processed product 3 is placed in the refrigerator compartment 1. The online infrared thermometer 2 measures the surface temperature of the refrigerated processed product 3 and transmits the data to the computer 8 via the data acquisition device 7. The computer 8 makes the following judgment:

[0052] (1) When the surface temperature of the refrigerated processed product 3 collected is lower than or equal to the preset temperature value, the compressor 9 remains off; in this embodiment, the preset temperature value is 6°C.

[0053] (2) When the surface temperature of the refrigerated processed product 3 is higher than the preset temperature value, the computer 8 controls the compressor 9 to start; at the same time, the first thermocouple thermometer 5 collects the surface temperature at the outlet end of the evaporator 6, and the second thermocouple thermometer 10 collects the surface temperature at the inlet end of the evaporator 6, and both are transmitted to the computer 8 through the data acquisition instrument 7. The computer 8 makes the following judgment:

[0054] If T1 > T+1, computer 8 controls compressor 9 to remain on.

[0055] If T+1≥T1>T-1, computer 8 controls compressor 9 to remain on and controls electronic expansion valve 4 to reduce its opening.

[0056] If T1 ≤ T-1, computer 8 controls compressor 9 to shut down;

[0057] Where T1 is the average temperature of the surface at the outlet end of evaporator 6 and the surface at the inlet end of evaporator 6, in °C; T is the average temperature control threshold of evaporator 6, in °C.

[0058] The average temperature control threshold T for evaporator 6 is calculated according to the following formula:

[0059]

[0060] In the formula, δ is the thickness of the refrigeration structure layer 17, in m, and in this embodiment, δ is 0.01 m; θ0 is the preset temperature value, in °C, and in this embodiment, θ0 is 6 °C; H is the height of the refrigeration structure layer 17, in m, and in this embodiment, H is 0.47 m; in this embodiment, the average temperature control threshold T of the evaporator 6 is -2.44 °C.

[0061] In this invention, a method to prevent wall icing is achieved by adjusting the height and thickness of the refrigeration structure layer 17 of the cold storage compartment 1, the surface temperature of the refrigerated processed product 3, the surface temperature at the outlet end of the evaporator 6, and the surface temperature at the inlet end of the evaporator 6. By using a non-contact measurement method and relying solely on directly measuring the surface temperature of the refrigerated processed product, the starting time of the compressor 9 and the opening degree of the electronic expansion valve 4 can be controlled. This ensures the preservation temperature of the refrigerated processed product while solving the problem of icing on the cold wall surface, and the control parameters are simple.

[0062] When calculating the average temperature control threshold of the evaporator using equation (1), the convective heat transfer inside the cold storage compartment is as shown in equation (2):

[0063] The heat exchange rate in refrigerator compartment 1 is:

[0064] Q lc =h(θ0-t) m (2)

[0065] Where h is the convective heat transfer coefficient; t m The temperature of the cold surface is 14, which is kept constant at 0℃.

[0066] The internal heat transfer of the cold surface 14 adopts the formula shown in (3):

[0067]

[0068] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for preventing wall icing based on online infrared temperature measurement technology, comprising a cold storage room (1) containing refrigerated processed products (3); An online infrared thermometer (2), installed on the inner top of the cold storage compartment (1), is used to collect the surface temperature of the refrigerated processed products (3); and A refrigeration system is used to cool the cold storage compartment (1); The refrigeration system includes an evaporator (6), an electronic expansion valve (4) installed at the inlet end of the evaporator (6), and a compressor (9) connected to the outlet end of the evaporator (6); a second thermocouple thermometer (10) is provided on the outer surface of the inlet end of the evaporator (6) for collecting the surface temperature of the inlet end of the evaporator (6); a first thermocouple thermometer (5) is provided on the outer surface of the outlet end of the evaporator (6) for collecting the surface temperature of the outlet end of the evaporator (6); It also includes a control system, which includes a data acquisition unit (7) and a computer (8); the input terminals of the data acquisition unit (7) are respectively connected to an online infrared thermometer (2), a first thermocouple thermometer (5) and a second thermocouple thermometer (10), and the output terminals of the data acquisition unit (7) are connected to the input terminals of the computer (8); the output terminals of the computer (8) are respectively connected to an electronic expansion valve (4) and a compressor (9); The cold storage compartment (1) has a rectangular parallelepiped structure and is insulated on the outside. A refrigeration structure layer (17) is provided on one side of the cold storage compartment (1), and the refrigeration structure layer (17) is attached to the cold surface (14) of the cold storage compartment (1). The cold storage compartment (1) is characterized in that... It also includes the following steps: S1: Measure the height and thickness of the refrigeration structure layer (17) of the cold storage compartment (1) and input them into the computer (8); S2: Place the refrigerated processed product (3) into the cold storage compartment (1), and use an online infrared thermometer (2) to measure the temperature of the surface of the refrigerated processed product (3). The temperature is then transmitted to the computer (8) via a data acquisition device (7). The computer (8) makes the following judgment: 1) When the surface temperature of the collected refrigerated processed product (3) is lower than or equal to the preset temperature value, the compressor (9) remains off; 2) When the surface temperature of the refrigerated processed product (3) is higher than the preset temperature value, the computer (8) controls the compressor (9) to start; at the same time, the first thermocouple thermometer (5) collects the surface temperature at the outlet end of the evaporator (6), and the second thermocouple thermometer (10) collects the surface temperature at the inlet end of the evaporator (6), and both are transmitted to the computer (8) through the data acquisition instrument (7). The computer (8) makes the following judgment: If T1 > T+1, the computer (8) controls the compressor (9) to remain on. If T+1≥T1>T-1, the computer (8) controls the compressor (9) to remain on and controls the electronic expansion valve (4) to reduce its opening. If T1≤T-1, the computer (8) controls the compressor (9) to shut down; Where T1 is the average temperature of the outlet surface temperature and the inlet surface temperature of the evaporator (6), in °C; T is the average temperature control threshold of the evaporator (6), in °C; The average temperature control threshold T of the evaporator (6) is calculated according to the following formula: In the formula, δ is the thickness of the refrigeration structure layer (17), m; θ0 is the preset temperature value, ℃; H is the height of the refrigeration structure layer (17), m.

2. The method for preventing wall icing based on online infrared temperature measurement technology according to claim 1, characterized in that, The evaporator (6) is fitted onto the surface of the cold side (14) located on one side of the refrigeration structure layer (17).

3. The method for preventing wall icing based on online infrared temperature measurement technology according to claim 1, characterized in that, The online infrared thermometer (2) is located at the center of the inner top of the cold storage room (1).

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