A system and method for measuring heat load of a refrigeration device cabinet

Abstract

The present invention discloses a measurement system for the heat load of a refrigeration device cabinet, comprising: a forward refrigeration system and a thermodynamic parameter measurement system. The forward refrigeration system is used to provide an actual refrigeration process and heat load, and provides a thermal environment for the thermodynamic parameter measurement system by simulating the refrigeration effect and controlling the temperature change. The thermodynamic parameter measurement system is used to monitor and record the thermodynamic parameters in the refrigeration process to evaluate the performance of the forward refrigeration system and calculate the heat load. In the present invention, the measurement system for the heat load of the refrigeration device cabinet restores the heat transfer load of the actual operating condition of the refrigeration cabinet 1 through forward heat transfer; it can switch between steady-state and dynamic modes, measure the steady-state heat load value and the dynamic heat load curve according to demand, and can take into account the measurement of non-steady-state heat load; through the forward measurement method of the heat load of the refrigeration device cabinet, the refrigeration temperature of the system is adjustable, which is convenient for measuring the steady-state and dynamic heat loads at different refrigeration temperatures.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration device heat load testing, and in particular to a system and method for measuring the heat load of a refrigeration device box. Background Art

[0002] The operating energy consumption of refrigeration units (such as refrigerators and freezers) is primarily influenced by the refrigeration system's energy efficiency and heat leakage within the refrigeration cabinet. The heat load of the refrigeration cabinet primarily depends on the thermophysical properties of the insulation material and the distribution of the insulation layer. This is particularly true given the demand for personalized spatial structural design of refrigeration units, which often leads to uneven insulation thickness distribution. The primary approach to reducing refrigeration cabinet operating energy consumption is to optimize the thickness distribution of the insulation layer. This requires accurate knowledge of the heat load distribution of the existing refrigeration cabinet, including the door seal, door body, and sidewalls.

[0003] In the prior art, the commonly used heat load test method is the reverse heat balance method. The reverse heat balance method is to adjust the heating power through the built-in heat source under the condition that the compressor of the refrigeration device is stopped, so that the temperature inside the box remains higher than a certain value of the external environment. When the temperature difference between the inside and outside of the box remains stable, it is considered to have reached thermal equilibrium. At this time, a heat flux meter can be used to measure the heat flux density of different parts of different refrigeration boxes, and then estimate the heat load. This method is widely used in engineering. The inventor used this method to perform measurements and found that there is a large difference between the measurement conditions of the reverse heat balance method and the actual operating conditions of the box, which makes the measurement of the heat load of the refrigeration device less accurate. Summary of the Invention

[0004] The purpose of the present invention is to solve the above-mentioned background technical problems and to provide a system and method for measuring the heat load of a refrigeration device cabinet.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A system for measuring the heat load of a refrigeration device cabinet, comprising: a forward refrigeration system and a thermal parameter measurement system, wherein the forward refrigeration system is used to provide an actual refrigeration process and heat load, and provides a thermal environment for the thermal parameter measurement system by simulating the refrigeration effect and controlling the temperature change; the forward refrigeration system comprises a refrigeration cabinet, an evaporator is arranged in the refrigeration cabinet, and two branches are arranged at the outlet of the evaporator, and the two branches are a coolant pipeline and a refrigerant pipeline respectively; the coolant pipeline is provided with a first stop valve, a water bath device, a variable frequency circulation pump, and a fourth stop valve in sequence along the flow direction of the coolant, and the refrigerant pipeline is provided with a second stop valve, a heat regenerator, a compressor, a condenser, a capillary tube, and a third stop valve in sequence along the flow direction of the refrigerant, and a condensing fan is arranged on one side of the condenser; the thermal parameter measurement system is used to monitor and record the refrigeration Thermodynamic parameters during the process are used to evaluate the performance of the forward refrigeration system and calculate the heat load; the thermal parameter measurement system includes: a controller, a collector and a workstation arranged outside the refrigeration box, the controller and the collector are connected to the workstation through a signal line; the collector is connected to a heat flux density sheet, a first thermocouple, a second thermocouple, a third thermocouple and a fourth thermocouple arranged inside the refrigeration box, and a fifth thermocouple, a first temperature sensor, a second temperature sensor, a first flow meter, a second flow meter, a third temperature sensor, a first pressure sensor, a fourth temperature sensor and a second pressure sensor located outside the refrigeration box through a signal line; the controller is connected to a temperature-controlled thermocouple, an evaporating fan, a water bath device, a variable frequency circulation pump, the condensing fan (13) and the compressor through a signal line.

[0007] As a further solution of the present invention: the temperature T detected by the temperature-controlled thermocouple c As the temperature control point inside the refrigeration box, its coordinates are The first thermocouple, the second thermocouple, the third thermocouple and the fourth thermocouple are arranged crosswise, and the temperatures detected by them are T1, T2, T3 and T4 respectively, and the coordinates are The average temperature of the four points is the characteristic temperature of the air area inside the refrigeration box; wherein x0, y0, z0 are the length, width and height of the cavity inside the refrigeration box respectively.

[0008] As a further solution of the present invention, the number n of heat flux density sheets arranged depends on the thermal resistance distribution of the insulation layer on the six surfaces of the refrigeration box. The six surfaces are divided into n different measurement areas according to the difference in wall thickness δ and thermal conductivity λ of the insulation material. The area of ​​the i-th measurement area is A i , the heat flux density of the i-th measurement area is q i , the heat load of the i-th measurement area is Q i =qi ×A i The total heat load of the refrigeration box insulation layer is

[0009] A forward measurement method for a refrigeration device cabinet heat load comprises:

[0010] S1. Preset a cooling temperature T s , open the first stop valve and the fourth stop valve, close the second stop valve and the third stop valve, make the forward refrigeration system enter the steady-state refrigeration mode, turn on the evaporation fan, adjust the outlet temperature of the water bath device and the operating frequency of the variable frequency circulation pump, so that the temperature detected by the temperature control sensor T c Close to the preset cooling temperature T s ;

[0011] S2, T c After stabilization, read the measured values ​​of the first temperature sensor, the second temperature sensor and the first flow meter. The measured values ​​are T medium,in 、T medium,out 、M medium , calculate the cooling capacity consumed by the evaporator, that is, the total heat load of the refrigeration box.

[0012] S3, preset a cooling temperature range [T s-low ,T s-up ], open the second stop valve and the third stop valve, close the first stop valve and the fourth stop valve, make the forward refrigeration system enter the dynamic refrigeration mode, adjust the start and stop status of the evaporating fan, condensing fan, and compressor, and make the temperature detected by the temperature control sensor T c In the preset refrigeration temperature range [T s-low ,T s-up ]Internal fluctuations;

[0013] S4, T c After the temperature remains stable, the measured values ​​of the second flow meter, the third temperature sensor, the first pressure sensor, the fourth temperature sensor, and the second pressure sensor are read. The measured values ​​are M refrigerant,l 、T refrigerant,l 、P refrigerant,l 、T refrigerant,g 、P refrigerant,g ;

[0014] S5. According to T refrigerant,l 、P refrigerant,l 、T refrigerant,g 、P refrigerant,g Obtain the enthalpy value H of liquid refrigerant and gaseous refrigerant from the NIST database refrigerant,l 、H refrigerant,g , calculate the cooling capacity consumed by the evaporator, that is, the total heat load of the refrigeration box.

[0015] As a further solution of the present invention: in step S2, the cooling capacity consumed by the evaporator is Q cooling =cM medium (T medium,in -T medium,out ), that is, the total heat load Q of the refrigeration box total =Q cooling ; Wherein, c is the specific heat capacity of the coolant.

[0016] As a further solution of the present invention: in step S5, the cooling capacity consumed by the evaporator is Q cooling =M refrigerant,l (H refrigerant,g -H refrigerant,l ), that is, the total heat load Q of the refrigeration box total =Q cooling .

[0017] As a further solution of the present invention: the door seal and door frame cold bridge heat load Q of the refrigeration box gasket It can be obtained indirectly, namely Q gasket =Q total -Q insulation .

[0018] Beneficial effects of the present invention:

[0019] (1) In the present invention, the refrigeration device cabinet heat load measurement system restores the heat transfer load of the refrigeration cabinet 1 under actual operating conditions through forward heat transfer.

[0020] (2) In the present invention, the steady-state and dynamic modes can be switched to each other, and the steady-state heat load value and the dynamic heat load curve can be measured according to demand. Compared with the reverse heat balance method which can only test the heat load under steady-state conditions, the present invention can also take into account the measurement of non-steady-state heat load.

[0021] (3) In the present invention, the forward measurement method of the heat load of the refrigeration device cabinet makes the refrigeration temperature of the system adjustable, which facilitates the measurement of steady-state and dynamic heat loads at different refrigeration temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below with reference to the accompanying drawings.

[0023] Figure 1 It is a schematic structural diagram of a system for measuring heat load of a refrigeration device cabinet according to the present invention;

[0024] Figure 2 It is a flow chart of a method for measuring the heat load of a refrigeration device cabinet according to the present invention;

[0025] Figure 3 This is a temperature cloud diagram of heat transfer of the refrigeration box door seal under actual working conditions of the present invention;

[0026] Figure 4 It is a temperature cloud diagram of heat transfer of the door seal of the refrigeration box under the reverse heat balance method working condition in the prior art of the present invention;

[0027] Figure 5 This is a schematic diagram of the thermal resistance distribution of a 133L refrigerator door according to the present invention;

[0028] Figure 6 Schematic diagram of thermal resistance distribution of the rear wall of a 133L refrigerator according to the present invention;

[0029] Figure 7 This is a schematic diagram of the thermal resistance distribution of the left wall of a 133L refrigerator of the present invention;

[0030] Figure 8 This is a schematic diagram of the thermal resistance distribution of the right wall of a 133L refrigerator according to the present invention;

[0031] Figure 9 This is a schematic diagram of the thermal resistance distribution of the top wall of a 133L refrigerator according to the present invention;

[0032] Figure 10 It is a schematic diagram of the thermal resistance distribution of the bottom wall of a 133L refrigerator of the present invention.

[0033] In the picture:

[0034] 1. Refrigeration cabinet; 2. Evaporator; 3. Evaporating fan; 4. First stop valve; 5. Second stop valve; 6. Water bath; 7. Frequency conversion circulation pump; 8. Third stop valve; 9. Fourth stop valve; 10. Capillary tube; 11. Regenerator; 12. Condenser; 13. Condensing fan; 14. Compressor; 15. Controller; 16. Collector; 17. Workstation; 18. Heat flux density plate; 19. Temperature control sensor; 20. First thermocouple; 21. Second thermocouple; 22. Third thermocouple; 23. Fourth thermocouple; 24. Fifth thermocouple; 25. First temperature sensor; 26. Second temperature sensor; 27. First flowmeter; 28. Second flowmeter; 29. ​​Third temperature sensor; 30. First pressure sensor; 31. Fourth temperature sensor; 32. Second pressure sensor. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] See also Figure 1As shown, the present invention is a measurement system for the heat load of a refrigeration device cabinet, including: a forward refrigeration system and a thermal parameter measurement system. The forward refrigeration system is used to provide an actual refrigeration process and heat load, and provides a thermal environment for the thermal parameter measurement system by simulating the refrigeration effect and controlling temperature changes.

[0037] Specifically, the forward refrigeration system includes a refrigeration box 1, an evaporator 2 is provided at the back plate position of the refrigeration box 1, and an evaporation fan 3 is provided on the top of the evaporator 2. Two branches are provided at the outlet of the evaporator 2, namely a coolant pipeline and a refrigerant pipeline.

[0038] Furthermore, the brine pipeline is provided with a first stop valve 4, a water bath 6, a variable frequency circulating pump 7, and a fourth stop valve 9, in the order in which the brine flows. The refrigerant pipeline is provided with a second stop valve 5, a regenerator 11, a compressor 14, a condenser 12, a capillary tube 10, and a third stop valve 8, in the order in which the refrigerant flows. A condensing fan 13 is provided on one side of the condenser 12. One end of the brine pipeline is connected to the outlet of the evaporator 2, and the other end is connected to the inlet of the evaporator 2. Correspondingly, one end of the refrigerant pipeline is connected to the outlet of the evaporator 2, and the other end is also connected to the inlet of the evaporator 2.

[0039] See also Figure 1 As shown, the thermal parameter measurement system is used to monitor and record the thermodynamic parameters during the refrigeration process to evaluate the performance of the forward refrigeration system and calculate the heat load.

[0040] Specifically, the thermal parameter measurement system includes: a controller 15 , a collector 16 and a workstation 17 arranged outside the refrigeration box 1 . The controller 15 and the collector 16 are connected to the workstation 17 via a signal line.

[0041] Furthermore, the collector 16 is connected to the heat flux density sheet 18, the first thermocouple 20, the second thermocouple 21, the third thermocouple 22 and the fourth thermocouple 23 arranged inside the refrigeration box 1, and the fifth thermocouple 24, the first temperature sensor 25, the second temperature sensor 26, the first flow meter 27, the second flow meter 28, the third temperature sensor 29, the first pressure sensor 30, the fourth temperature sensor 31 and the second pressure sensor 32 located outside the refrigeration box 1 through a signal line. Among them, the fifth thermocouple 24 is an environmental thermocouple for detecting the external ambient temperature. The first temperature sensor 25, the second temperature sensor 26 and the first flow meter 27 are all arranged on the coolant pipeline. The first temperature sensor 25 is used to monitor the coolant temperature at the inlet of the water bath device 6, the second temperature sensor 26 is used to monitor the coolant temperature at the outlet of the water bath device 6, and the first flow meter 27 is used to monitor the real-time flow of the coolant. The second flow meter 28, the third temperature sensor 29, the first pressure sensor 30, the fourth temperature sensor 31 and the second pressure sensor 32 are all arranged on the refrigerant pipeline. The second flow meter 28 is used to monitor the flow rate of the liquid refrigerant, the third temperature sensor 29 is used to monitor the temperature of the liquid refrigerant, the first pressure sensor 30 is used to monitor the pressure of the liquid refrigerant in the refrigerant pipeline, the fourth temperature sensor 31 is used to monitor the temperature of the gaseous refrigerant, and the second pressure sensor 32 is used to monitor the pressure of the gaseous refrigerant in the refrigerant pipeline.

[0042] Furthermore, the controller 15 is connected to the temperature control thermocouple 19, the evaporating fan 3, the water bath device 6, the variable frequency circulation pump 7, the condensing fan 13 and the compressor 14 via signal lines. The temperature control thermocouple 19 is arranged inside the refrigeration box 1.

[0043] Specifically, the temperature T detected by the temperature control thermocouple 19 c As the temperature control point inside the refrigeration box 1, its coordinates are The first thermocouple 20, the second thermocouple 21, the third thermocouple 22, and the fourth thermocouple 23 are arranged crosswise, and the temperatures detected are T1, T2, T3, and T4 respectively. The coordinates of the first thermocouple 20, the second thermocouple 21, the third thermocouple 22, and the fourth thermocouple 23 are respectively The average temperature of the four points is the characteristic temperature of the air area in the refrigeration box 1. Wherein, x0, y0, z0 are the length, width and height of the cavity inside the refrigeration box 1 respectively.

[0044] Moreover, the number n of heat flux sheets 18 depends on the thermal resistance distribution of the insulation layer on the six sides of the refrigeration box 1. The six sides are divided into n different measurement areas according to the difference in wall thickness δ and thermal conductivity λ of the insulation material. The area of ​​the i-th measurement area is A i, the heat flux density of the i-th measurement area is q i , the heat load of the i-th measurement area is Q i =q i ×A i , the total heat load of the insulation layer of the refrigeration box 1 is

[0045] See also Figure 3-Figure 4 As shown, the heat load test method commonly used in the prior art is the reverse heat balance method, which is widely used in engineering. The inventors used the reverse heat balance method for measurement. However, the inventors found that there is a significant difference between the measurement conditions of the reverse heat balance method and the actual operating conditions of the box, as follows:

[0046] In actual operating conditions, the anti-condensation pipe at the door frame of the cabinet is in a heated state. Under the reverse heat balance method, the refrigeration unit is powered off, the compressor is not turned on, and the anti-condensation pipe fails to heat up, which changes the local heat transfer state of the cabinet.

[0047] Moreover, the fan inside the refrigeration unit is in intermittent operation and is located on the side of the evaporator. Under the reverse heat balance method, the original fan does not run and the external fan cannot be placed on the side of the evaporator, causing the flow field inside the refrigeration box to be different from the flow field under actual operation, thereby changing the heat transfer state inside the box.

[0048] Under the reverse heat balance method, the internal temperature is higher than the external temperature due to the action of the built-in heat source, and the direction of heat transfer is from the inside of the refrigeration box to the external environment, which is inconsistent with the actual operating conditions of the refrigeration device products. In actual operation, the external temperature is higher than the internal temperature, and the direction of heat transfer is from the external environment to the inside of the refrigeration box. Due to the irregular insulation structure of the refrigeration box (such as door shelves, door seals, drawer ribs, etc.), when the heat flow is transferred inward and outward, although the temperature difference is the same, there is a difference in the size of the heat load.

[0049] The purpose of the reverse heat balance method is to maintain a thermal equilibrium state and it can only test the heat load under steady-state conditions. However, during the actual operation of the refrigeration device, the start and stop states of the compressor are controlled by temperature, and the refrigeration box is always in a non-steady-state condition with periodic temperature rise and fall. The non-steady-state heat load is required for measurement, and the reverse heat balance method cannot take into account the non-steady-state heat load.

[0050] In addition, according to the public paper "Research Progress on Key Technologies for Improving the Performance of Flexible Contact Sealing Mechanisms in Refrigeration Devices", under actual refrigeration conditions and reverse thermal equilibrium, the heat load of the door seal was 2.47W / m and 3.23W / m respectively, with a deviation of more than 30%, further confirming that the accuracy of heat load measurement using the reverse thermal balance method is not high.

[0051] See also Figure 2As shown, in another embodiment, a forward measurement method of a heat load of a refrigeration device cabinet includes:

[0052] S1. Preset a cooling temperature T s , open the first stop valve 4 and the fourth stop valve 9, close the second stop valve 5 and the third stop valve 8, so that the forward refrigeration system enters the steady-state refrigeration mode, turn on the evaporation fan 3, adjust the outlet temperature of the water bath device 6 and the operating frequency of the variable frequency circulation pump 7, so that the temperature detected by the temperature control sensor 19 is T c Close to the preset cooling temperature T s .

[0053] S2, T c After the temperature remains stable, the measured values ​​of the first temperature sensor 25, the second temperature sensor 26 and the first flow meter 27 are read. The measured values ​​are T medium,in 、T medium,out 、M medium , calculate the cooling capacity consumed by the evaporator 2, that is, the total heat load of the refrigeration box 1. At this time, the total heat load of the refrigeration box 1 is the steady-state heat load.

[0054] The cooling capacity consumed by evaporator 2 is Q cooling =cM medium (T medium,in -T medium,out ), that is, the total heat load Q of the refrigeration box 1 total =Q cooling Where c is the specific heat capacity of the coolant.

[0055] S3, preset a cooling temperature range [T s-low ,T s-up ], open the second stop valve 5 and the third stop valve 8, close the first stop valve 4 and the fourth stop valve 9, so that the forward refrigeration system enters the dynamic refrigeration mode, adjust the start and stop status of the evaporating fan 3, the condensing fan 13, and the compressor 14, and make the temperature T detected by the temperature control sensor 19 c In the preset refrigeration temperature range [T s-low ,T s-up ]Internal fluctuations.

[0056] S4, T c After the temperature remains stable, the measured values ​​of the second flow meter 28, the third temperature sensor 29, the first pressure sensor 30, the fourth temperature sensor 31, and the second pressure sensor 32 are read. The measured values ​​are M refrigerant,l 、T refrigerant,l 、P refrigerant,l 、T refrigerant,g 、P refrigerant,g .

[0057] S5. According to T refrigerant,l 、Prefrigerant,l 、T refrigerant,g 、P refrigerant,g Obtain the enthalpy value H of liquid refrigerant and gaseous refrigerant from the NIST database refrigerant,l 、H refrigerant,g , calculate the cooling capacity consumed by the evaporator 2, that is, the total heat load of the refrigeration box 1. At this time, the total heat load of the refrigeration box 1 is the dynamic heat load.

[0058] The cooling capacity consumed by evaporator 2 is Q cooling =M refrigerant,l (H refrigerant,g -H refrigerant,l ), that is, the total heat load Q of the refrigeration box 1 total =Q cooling .

[0059] It is understandable that the door seal and door frame cold bridge heat load Q of the refrigeration box 1 gasket It can be obtained indirectly, namely Q gasket =Q total -Q insulation .

[0060] In this application, the refrigeration cabinet heat load measurement system uses forward heat transfer to restore the heat transfer load of the refrigeration cabinet 1 under actual operating conditions. It can switch between steady-state and dynamic modes to measure steady-state heat load values ​​and dynamic heat load curves as needed. Compared to the reverse heat balance method, which can only measure heat load under steady-state conditions, the present invention can also take into account the measurement of unsteady-state heat loads.

[0061] The forward measurement method of the heat load of the refrigeration device cabinet makes the refrigeration temperature of the system adjustable, which is convenient for measuring the steady-state and dynamic heat loads at different refrigeration temperatures.

[0062] The following are experiments and experimental data using the system and method for measuring the heat load of a refrigeration device cabinet in the present invention:

[0063] See also Figure 5-10 As shown in the figure, for a 133L single-door refrigerator, the ambient temperature is set to 25°C and the temperature inside the refrigerator is set to -18°C. Based on the thermal resistance distribution, the wall surface of the 133L single-door refrigerator is divided into 48 measurement areas.

[0064] See also Figure 1 As shown, the first and fourth stop valves 4 and 9 are opened, and the second and third stop valves 5 and 8 are closed, causing the forward refrigeration system to enter steady-state refrigeration mode. The evaporating fan 3 is turned on, and the outlet temperature of the water bath 6 and the operating frequency of the variable-frequency circulation pump 7 are adjusted so that the temperature detected by the temperature control sensor 19 is close to the preset refrigeration temperature, i.e., -18°C. At this time, the heat flux density and heat load of various parts of the refrigerator are measured using a heat flux meter 18. The specific data are shown in the following table:

[0065] Table 1 Heat loads of different parts of the refrigerator under positive steady-state equilibrium conditions

[0066]

[0067]

[0068] From Table 1, we know that the heat load of the refrigerator wall is 14.311W, while the cooling capacity measured by the flow rate of the refrigerant and the temperature difference before and after the evaporator is 16.512W. It can be seen that the heat load of the door seal is 2.201W, and the heat load accounts for 13.3%.

[0069] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A system for measuring heat load of a refrigeration cabinet, characterized in that: include: A forward refrigeration system and a thermal parameter measurement system. The forward refrigeration system is used to provide an actual refrigeration process and heat load, and provides a thermal environment for the thermal parameter measurement system by simulating the refrigeration effect and controlling temperature changes. The forward refrigeration system comprises a refrigeration box (1), an evaporator (2) is arranged in the refrigeration box (1), and two branches are arranged at the outlet of the evaporator (2), the two branches being a coolant pipeline and a refrigerant pipeline respectively; The secondary coolant pipeline is provided with a first stop valve (4), a water bath device (6), a variable frequency circulation pump (7), and a fourth stop valve (9) in sequence along the direction of secondary coolant flow; the refrigerant pipeline is provided with a second stop valve (5), a regenerator (11), a compressor (14), a condenser (12), a capillary tube (10), and a third stop valve (8) in sequence along the direction of refrigerant flow; and a condensing fan (13) is provided on one side of the condenser (12); The thermal parameter measurement system is used to monitor and record the thermodynamic parameters during the refrigeration process to evaluate the performance of the forward refrigeration system and calculate the heat load; The thermal parameter measurement system comprises: a controller (15), a collector (16) and a workstation (17) arranged outside the refrigeration box (1), wherein the controller (15) and the collector (16) are connected to the workstation (17) via a signal line; The collector (16) is connected to a heat flux sheet (18), a first thermocouple (20), a second thermocouple (21), a third thermocouple (22), and a fourth thermocouple (23) arranged inside the refrigeration box (1), and a fifth thermocouple (24), a first temperature sensor (25), a second temperature sensor (26), a first flow meter (27), a second flow meter (28), a third temperature sensor (29), a first pressure sensor (30), a fourth temperature sensor (31), and a second pressure sensor (32) located outside the refrigeration box (1) via a signal line; The controller (15) is connected to a temperature-controlled thermocouple (19), an evaporating fan (3), a water bath device (6), a variable frequency circulation pump (7), the condensing fan (13) and the compressor (14) via a signal line.

2. A refrigeration device cabinet heat load measurement system according to claim 1, characterized in that: The temperature T detected by the temperature-controlled thermocouple (19) c As the temperature control point inside the refrigeration box (1), its coordinates are The first thermocouple (20), the second thermocouple (21), the third thermocouple (22), and the fourth thermocouple (23) are arranged crosswise, and the temperatures detected by them are T1, T2, T3, and T4, respectively, and the coordinates are The average temperature of the four points is the characteristic temperature of the air area in the refrigeration box (1); Wherein, x0, y0, z0 are respectively the length, width and height of the internal cavity of the refrigeration box (1).

3. A refrigeration device cabinet heat load measurement system according to claim 1, characterized in that: The number n of heat flux density sheets (18) arranged depends on the thermal resistance distribution of the insulation layers on the six surfaces of the refrigeration box (1). The six surfaces are divided into n different measurement areas according to the difference in wall thickness δ and thermal conductivity λ of the insulation material. The area of ​​the i-th measurement area is A i , the heat flux density of the i-th measurement area is q i , the heat load of the i-th measurement area is Q i =q i ×A i The total heat load of the insulation layer of the refrigeration box (1) is 4. A method for using the refrigeration device cabinet heat load measurement system according to any one of claims 1 to 3, characterized in that: include: S1. Preset a cooling temperature T s , open the first stop valve (4) and the fourth stop valve (9), close the second stop valve (5) and the third stop valve (8), so that the forward refrigeration system enters the steady-state refrigeration mode, turn on the evaporation fan (3), adjust the outlet temperature of the water bath device (6) and the operating frequency of the variable frequency circulation pump (7), so that the temperature T detected by the temperature control sensor (19) is c Close to the preset cooling temperature T s ; S2, T c After the temperature remains stable, the measured values ​​of the first temperature sensor (25), the second temperature sensor (26) and the first flow meter (27) are read. The measured values ​​are T medium,in 、T medium,out 、M medium , calculate the cooling capacity consumed by the evaporator (2), i.e. the total heat load of the refrigeration box (1); S3, preset a cooling temperature range [T s-low ,T s-up ], open the second stop valve (5) and the third stop valve (8), close the first stop valve (4) and the fourth stop valve (9), so that the forward refrigeration system enters the dynamic refrigeration mode, adjusts the start and stop states of the evaporating fan (3), the condensing fan (13), and the compressor (14), and makes the temperature T detected by the temperature control sensor (19) c In the preset refrigeration temperature range [T s-low ,T s-up ]Internal fluctuations; S4, T c After the temperature remains stable, the measured values ​​of the second flow meter (28), the third temperature sensor (29), the first pressure sensor (30), the fourth temperature sensor (31), and the second pressure sensor (32) are read. The measured values ​​are M refrigerant,l 、T refrigerant,l 、P refrigerant,l 、T refrigerant,g 、P refrigerant,g ; S5. According to T refrigerant,l 、P refrigerant,l 、T refrigerant,g 、P refrigerant,g Obtain the enthalpy value H of liquid refrigerant and gaseous refrigerant from the NIST database refrigerant,l 、H refrigerant,g , calculate the cooling capacity consumed by the evaporator (2), that is, the total heat load of the refrigeration box (1).

5. The method according to claim 4, characterized in that In step S2, the cooling capacity consumed by the evaporator (2) is Q cooling =cM medium (T medium,in -T medium,out ), that is, the total heat load Q of the refrigeration box (1) total =Q cooling ; Where c is the specific heat capacity of the coolant.

6. The method according to claim 4, characterized in that In step S5, the cooling capacity consumed by the evaporator (2) is Q cooling =M refrigerant,l (H refrigerant,g -H refrigerant,l ), i.e. the total heat load Q of the refrigeration box (1) total =Q cooling .

7. The method according to claim 4, characterized in that The door seal and door frame cold bridge heat load Q of the refrigeration box (1) gasket It can be obtained indirectly, namely Q gasket =Q total -Q insulation .

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