A method and system for testing the sky radiation heat exchange coefficient

Abstract

The application discloses a kind of sky radiation equivalent heat transfer coefficient test method and system, comprising: obtaining the air parameters near composite radiation plate obtained by the sky radiation refrigeration process test of roof composite radiation plate, the temperature of composite radiation plate surface and inside;According to the temperature of measured composite radiation plate surface and inside, the temperature distribution curve in the thickness direction of composite radiation plate is fitted to obtain, and then the temperature gradient and heat transfer amount of composite radiation plate surface are obtained;According to the wind speed and air temperature near composite radiation plate, the surface temperature of composite radiation plate and the characteristic number correlation formula of heat transfer of hot air and composite radiation plate surface, the surface convective heat transfer coefficient and surface convective heat transfer amount are obtained, and the sky radiation refrigeration capacity is obtained by combining the heat transfer amount of composite radiation plate surface;Effective sky temperature is estimated according to air temperature and relative humidity, and sky radiation equivalent heat transfer coefficient is calculated according to sky radiation refrigeration capacity, composite radiation plate surface temperature and effective sky temperature.

Description

Technical Field

[0001] This invention relates to a method and system for testing the equivalent heat transfer coefficient of sky radiation, belonging to the field of natural energy utilization technology. Background Technology

[0002] Sky radiation cooling utilizes long-wave radiation heat exchange between a radiating surface and the sky for passive cooling. It does not consume external energy and has been applied in fields such as passive cooling of buildings and heat dissipation of equipment.

[0003] The radiative heat transfer between a radiating surface and the sky is usually calculated using the Stefan-Boltzmann theorem, i.e., the fourth power law. However, when analyzing the process of heat transfer from a radiating surface to an inner medium (such as water), the boundary conditions outside the radiating surface include multiple processes such as radiative heat transfer with the sky and convective heat transfer with the ambient air. Using the fourth power law to describe radiative heat transfer increases the difficulty of solving the problem. If radiative heat transfer is equivalent to convective heat transfer, the problem can be simplified. Summary of the Invention

[0004] Objective: In order to overcome the shortcomings of the existing technology, the present invention provides a method and system for testing the equivalent heat transfer coefficient of sky radiation.

[0005] First, the heat transfer between the air and the radiant surface is calculated based on the heat balance equation of the outer surface of the composite radiant panel (with an internal heat source) in the air duct. Then, the surface convective heat transfer coefficient is calculated, and the characteristic number correlation of the surface convective heat transfer is obtained by fitting. Next, the composite radiant panel is placed on the building roof. The heat dissipation of the outer surface of the radiant panel is calculated based on the heat balance equation of the outer surface of the composite radiant panel under convective heat transfer + radiative heat transfer conditions. Then, the convective heat transfer between the air and the radiant surface is calculated based on the measured wind speed and air temperature near the radiant panel, the outer surface temperature of the radiant panel, and geometric parameters. The radiative heat transfer between the sky and the surface of the radiant panel is then extrapolated, and finally, the equivalent radiative heat transfer coefficient of the sky is calculated.

[0006] Technical solution: To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for testing the equivalent heat transfer coefficient of sky radiation, comprising:

[0008] The air parameters near the composite radiant roof panel and the surface and internal temperatures of the composite radiant roof panel were obtained from a sky radiation cooling process test. The air parameters included wind speed u and air temperature t. air and relative humidity

[0009] Based on the measured temperatures of the composite radiant plate's surface and interior, a temperature distribution curve t = f(y) along the thickness direction inside the composite radiant plate is fitted, and then the temperature gradient and thermal conductivity Q at the surface of the composite radiant plate are calculated. cond ;

[0010] Based on the wind speed u and temperature t near the composite radiant panel air Surface temperature t of composite radiant panel surface And using the characteristic correlation Nu=f(Re,Pr) for convective heat transfer between hot air and the surface of the composite radiant plate, the surface convective heat transfer coefficient h can be obtained. conv and surface convection heat transfer Q conv Combined with the thermal conductivity Q of the composite radiant plate surface cond Obtain the cooling capacity Q from the sky radiation sky =Q conv +Q cond ;

[0011] According to temperature t air and relative humidity The effective sky temperature t was estimated. sky According to the cooling capacity Q of sky radiation sky Surface temperature t of composite radiant panel surface and effective sky temperature t sky The equivalent heat transfer coefficient h of sky radiation was calculated. r .

[0012] In some embodiments, the characteristic number correlation of the convective heat transfer between the hot air and the surface of the composite radiant plate includes:

[0013] Nu = f(Re, Pr)

[0014] In the formula, h conv λ is the convective heat transfer coefficient of the composite radiant plate surface, l is the length of the composite radiant plate in the airflow direction, and λ is the thermal conductivity of the composite radiant plate. u is the wind speed near the surface of the composite radiant panel, and ν is the kinematic viscosity of the air. 'a' represents the thermal diffusivity of air, based on the air temperature t. air Sure.

[0015] Furthermore, in some embodiments, the method for obtaining the characteristic number correlation of the convective heat transfer between the hot air and the surface of the composite radiant plate includes:

[0016] The temperatures of the composite radiant plate surface and interior, and the air temperature near the composite radiant plate surface were obtained from the convective heat transfer process test within the air duct. air With the surface temperature t of the composite radiant plate surface ;

[0017] Based on the measured temperatures of the composite radiant plate's surface and interior, a temperature distribution curve t = f(y) along the thickness direction inside the composite radiant plate is fitted, and then the temperature gradient and thermal conductivity Q at the surface of the composite radiant plate are calculated. cond ;

[0018] Based on thermal conductivity Q cond and the air temperature t near the surface of the composite radiant panel air With the surface temperature t of the composite radiant plate surface The convective heat transfer coefficient h on the surface of the composite radiant plate was obtained. conv ;

[0019] Based on the convective heat transfer coefficient h of the composite radiant plate surface under different conditions conv The characteristic correlation of convective heat transfer between hot air and the surface of the composite radiant plate was obtained by fitting, which is Nu=f(Re,Pr).

[0020] In some embodiments, based on the measured temperatures of the surface and interior of the composite radiant plate, a temperature distribution curve t = f(y) along the thickness direction inside the composite radiant plate is fitted, and then the temperature gradient and thermal conductivity Q at the surface of the composite radiant plate are calculated. cond ,include:

[0021]

[0022] In the formula, λ is the thermal conductivity of the composite radiant plate; A is the surface area of ​​the composite radiant plate. This represents the temperature gradient at the surface of the composite radiant plate.

[0023] In some embodiments, based on thermal conductivity Q cond and the air temperature t near the surface of the composite radiant panel air With the surface temperature t of the composite radiant plate surface The convective heat transfer coefficient h on the surface of the composite radiant plate was obtained. conv include:

[0024] During the convective heat transfer process on the surface of the composite radiant plate inside the air duct, according to the heat balance of the composite radiant plate surface, the surface convective heat transfer rate Q is... conv Equal to the thermal conductivity Q at the surface cond Furthermore, based on the measured air temperature t near the surface of the composite radiation plate... air With the surface temperature t of the composite radiant plate surface The convective heat transfer coefficient h on the surface of the composite radiant plate was obtained. conv :

[0025]

[0026] In the formula, Q convThe value is equal to the calculated thermal conductivity Q at the surface of the composite radiant plate. cond A represents the surface area of ​​the composite radiant panel.

[0027] In some embodiments, the test of the convective heat transfer process on the surface of the composite radiant plate in the duct includes:

[0028] The composite radiant panel is placed in the air duct, the inner surface of the air duct is a radiant insulation surface, and the air duct is sequentially equipped with a speed-regulating fan, flexible connection, electric heating coil, radiant shielding plate, and reducer. Wind speed and temperature measuring points are set above the composite radiant panel.

[0029] Turn on the power switch of the electric heating coil. After the electric heating coil has stabilized and heated up, turn on the speed-regulating fan to allow hot air to pass over the surface of the composite radiant plate. Through convection heat transfer, the temperature of the radiant plate and the lower heat storage plate will slowly rise. Collect the temperature of the surface and interior of the composite radiant plate at different times, as well as the air temperature near the surface of the composite radiant plate and the surface temperature of the composite radiant plate.

[0030] In some embodiments, the sky radiation cooling process test of the roof composite radiant panel includes:

[0031] The composite radiant panel is placed on the roof of the building, and outdoor air parameter measuring points are set above the composite radiant panel to test the nighttime sky radiation cooling process, and collect air parameters near the composite radiant panel and temperature data of the surface and interior of the composite radiant panel.

[0032] In some embodiments, the composite radiant plate includes a radiant plate, a heat storage plate assembly, and a thermocouple;

[0033] The heat storage plate assembly includes multiple layers of heat storage plates stacked along their thickness direction, and thermocouples for measuring temperature are arranged between adjacent heat storage plates.

[0034] The radiant plate is covered on the heat storage plate assembly. A thermocouple for measuring the surface temperature of the composite radiant plate is provided on the upper surface of the radiant plate. A thermocouple for measuring temperature is arranged between the radiant plate and the heat storage plate assembly.

[0035] Furthermore, in some embodiments, the composite radiant panel is wrapped with an insulation layer around its perimeter and bottom to reduce heat exchange between the composite radiant panel and the surrounding environment.

[0036] In some embodiments, based on the sky radiation cooling capacity Q sky Surface temperature t of composite radiant panel surface and effective sky temperature t sky The equivalent heat transfer coefficient h of sky radiation was calculated. r ,include:

[0037]

[0038] In the formula, A is the surface area of ​​the composite radiant panel.

[0039] Secondly, the present invention provides a testing system for the equivalent heat transfer coefficient of sky radiation, including a processor and a storage medium;

[0040] The storage medium is used to store instructions;

[0041] The processor is configured to operate according to the instructions to execute the method according to the first aspect.

[0042] Thirdly, the present invention provides an apparatus comprising,

[0043] Memory;

[0044] processor;

[0045] as well as

[0046] Computer programs;

[0047] The computer program is stored in the memory and configured to be executed by the processor to implement the method described in the first aspect above.

[0048] Fourthly, the present invention provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect.

[0049] Beneficial effects: The test method and system for the equivalent heat transfer coefficient of sky radiation provided by the present invention have the following advantages: (1) The present invention combines a radiation plate with a multi-layer heat storage plate to form a composite radiation plate. By testing the temperature distribution on the surface and inside of the composite radiation plate, the heat transfer on the surface of the radiation plate is calculated.

[0050] (2) The present invention uses the thermal balance of the composite radiation plate surface during the sky radiation cooling process to calculate the sky radiation cooling capacity.

[0051] (3) This invention provides a method for testing the equivalent heat transfer coefficient of sky radiation, which can simplify the analysis of complex heat transfer problems of sky radiation refrigeration devices. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of a composite radiating plate according to an embodiment of the present invention;

[0053] Figure 2 This is a schematic diagram of a test system for the convective heat transfer process on the surface of a composite radiant plate inside a duct, according to an embodiment of the present invention.

[0054] Figure 3 This is a schematic diagram of the temperature fitting curve inside the composite radiant plate according to an embodiment of the present invention;

[0055] Figure 4 This is a schematic diagram of a test system for the sky radiation cooling process of a roof composite radiant panel according to an embodiment of the present invention;

[0056] Figure 5 This is a schematic diagram of the sky radiation equivalent heat transfer coefficient test process according to an embodiment of the present invention.

[0057] In the diagram: 1-Composite radiant panel; 2-Radiant panel; 3-Heat storage plate; 4-Thermocouple; 5-Insulation layer; 6-Air duct; 7-Variable speed fan; 8-Flexible joint; 9-Electric heating coil; 10-Radiant shielding plate; 11-Wind speed and temperature measuring points; 12-Reducing pipe; 13-Wind speed, air temperature and humidity measuring points. Detailed Implementation

[0058] The present invention will be further described below with reference to the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and should not be used to limit the scope of protection of the present invention.

[0059] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0060] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] Example 1

[0062] Firstly, this embodiment provides a method for testing the equivalent heat transfer coefficient of sky radiation, including:

[0063] The air parameters near the composite radiant roof panel and the surface and internal temperatures of the composite radiant roof panel were obtained from a sky radiation cooling process test. The air parameters included wind speed u and air temperature t. air and relative humidity

[0064] Based on the measured temperatures of the composite radiant plate's surface and interior, a temperature distribution curve t = f(y) along the thickness direction inside the composite radiant plate is fitted, and then the temperature gradient and thermal conductivity Q at the surface of the composite radiant plate are calculated. cond ;

[0065] Based on the wind speed u and temperature t near the composite radiant panel air Surface temperature t of composite radiant panel surface And using the characteristic correlation Nu=f(Re,Pr) for convective heat transfer between hot air and the surface of the composite radiant plate, the surface convective heat transfer coefficient h can be obtained. conv and surface convection heat transfer Q conv Combined with the thermal conductivity Q of the composite radiant plate surface cond Obtain the cooling capacity Q from the sky radiation sky =Q conv +Q cond ;

[0066] According to temperature t air and relative humidity The effective sky temperature t was estimated. sky According to the cooling capacity Q of sky radiation sky Surface temperature t of composite radiant panel surface and effective sky temperature t sky The equivalent heat transfer coefficient h of sky radiation was calculated. r .

[0067] In some embodiments, the characteristic number correlation of the convective heat transfer between the hot air and the surface of the composite radiant plate includes:

[0068] Nu = f(Re, Pr)

[0069] In the formula, h conv λ is the convective heat transfer coefficient of the composite radiant plate surface, l is the length of the composite radiant plate in the airflow direction, and λ is the thermal conductivity of the composite radiant plate. u is the wind speed near the surface of the composite radiant panel, and ν is the kinematic viscosity of the air. 'a' represents the thermal diffusivity of air, based on the air temperature t. air Sure.

[0070] Furthermore, in some embodiments, the method for obtaining the characteristic number correlation of the convective heat transfer between the hot air and the surface of the composite radiant plate includes:

[0071] The temperatures of the composite radiant plate surface and interior, and the air temperature near the composite radiant plate surface were obtained from the convective heat transfer process test within the air duct. air With the surface temperature t of the composite radiant plate surface ;

[0072] Based on the measured temperatures of the composite radiant plate's surface and interior, a temperature distribution curve t = f(y) along the thickness direction inside the composite radiant plate is fitted, and then the temperature gradient and thermal conductivity Q at the surface of the composite radiant plate are calculated. cond ;

[0073] Based on thermal conductivity Q cond and the air temperature t near the surface of the composite radiant panel air With the surface temperature t of the composite radiant plate surface The convective heat transfer coefficient h on the surface of the composite radiant plate was obtained. conv ;

[0074] Based on the convective heat transfer coefficient h of the composite radiant plate surface under different conditions conv The characteristic correlation of convective heat transfer between hot air and the surface of the composite radiant plate was obtained by fitting, which is Nu=f(Re,Pr).

[0075] In some embodiments, based on the measured temperatures of the surface and interior of the composite radiant plate, a temperature distribution curve t = f(y) along the thickness direction inside the composite radiant plate is fitted, and then the temperature gradient and thermal conductivity Q at the surface of the composite radiant plate are calculated. cond ,include:

[0076]

[0077] In the formula, λ is the thermal conductivity of the radiating plate, W / (m·℃); A is the surface area of ​​the composite radiating plate, m². 2 ; denoted as the temperature gradient at the surface of the composite radiant plate, in °C / m.

[0078] In some embodiments, based on thermal conductivity Q cond and the air temperature t near the surface of the composite radiant panel air With the surface temperature t of the composite radiant plate surface The convective heat transfer coefficient h on the surface of the composite radiant plate was obtained. conv include:

[0079] During the convective heat transfer process on the surface of the composite radiant plate inside the air duct, according to the heat balance of the composite radiant plate surface, the surface convective heat transfer rate Q is... conv Equal to the thermal conductivity Q at the surface cond Furthermore, based on the measured air temperature t near the surface of the composite radiation plate... air With the surface temperature t of the composite radiant plate surface The convective heat transfer coefficient h on the surface of the composite radiant plate was obtained. conv :

[0080]

[0081] In the formula, Qconv The value is equal to the calculated thermal conductivity Q at the surface of the composite radiant plate. cond A represents the surface area of ​​the composite radiant panel.

[0082] In some embodiments, based on the sky radiation cooling capacity Q sky Surface temperature t of composite radiant panel surface and effective sky temperature t sky The equivalent heat transfer coefficient h of sky radiation was calculated. r ,include:

[0083]

[0084] In the formula, A is the surface area of ​​the composite radiant panel.

[0085] In some embodiments, such as Figure 1 As shown, the composite radiant plate 1 is the main part of the present invention, including: a radiant plate 2, a heat storage plate assembly 3, and a thermocouple 4;

[0086] The heat storage plate assembly 3 includes multiple layers of heat storage plates stacked along its thickness direction, and thermocouples 4 for measuring temperature are arranged between adjacent heat storage plates.

[0087] The radiant plate 2 is covered on the heat storage plate assembly 3. A thermocouple for measuring the surface temperature of the composite radiant plate is provided on the upper surface of the radiant plate. A thermocouple for measuring temperature is arranged between the radiant plate and the heat storage plate assembly.

[0088] Preferably, in the heat storage plate assembly 3, each heat storage plate has the same thickness.

[0089] Furthermore, in some embodiments, the composite radiant panel 1 is wrapped with an insulation layer 5 around its sides and bottom to reduce heat exchange between the composite radiant panel and the surrounding environment.

[0090] In some embodiments, such as Figure 2 The image shows a test system for the convective heat transfer process on the surface of a composite radiant panel inside a duct; the test of the convective heat transfer process on the surface of the composite radiant panel inside the duct includes:

[0091] The composite radiant panel is placed in the air duct 6. The inner surface of the air duct is a radiant insulation surface. The air duct is sequentially equipped with a speed-regulating fan 7, a flexible connector 8, an electric heating coil 9, a radiant shielding plate 10, and a reducing pipe 12. Wind speed and temperature measuring points 11 are set above the composite radiant panel.

[0092] Turn on the power switch of the electric heating coil. After the electric heating coil has stabilized and heated up, turn on the speed-regulating fan to allow hot air to pass over the surface of the composite radiant plate. Through convection heat transfer, the temperature of the radiant plate and the lower heat storage plate will slowly rise. Collect the temperature of the surface and interior of the composite radiant plate at different times, as well as the air temperature near the surface of the composite radiant plate and the surface temperature of the composite radiant plate.

[0093] like Figure 3 As shown, the temperature fitting curve inside the composite radiant panel is obtained by fitting the surface and internal temperature of the composite radiant panel based on the convective heat transfer process test of the composite radiant panel surface in the air duct, and by fitting the surface and internal temperature of the composite radiant panel based on the sky radiation cooling process test of the roof composite radiant panel.

[0094] In some embodiments, such as Figure 4 The diagram shows a test system for the sky radiation cooling process of a roof composite radiant panel. The test of the sky radiation cooling process of the roof composite radiant panel includes: placing the composite radiant panel 1 on the roof of the building, setting outdoor wind speed, air temperature and humidity measuring points 13 above the composite radiant panel, conducting a test of the nighttime sky radiation cooling process, and collecting air parameters near the composite radiant panel and temperature data of the surface and interior of the composite radiant panel.

[0095] like Figure 5 As shown, the test procedure for the equivalent heat transfer coefficient of sky radiation provides the main test content, data, intermediate parameters obtained from calculation, and the entire process of finally determining the equivalent heat transfer coefficient of sky radiation.

[0096] First, construct as follows Figure 1 The composite radiant panel shown has an outer surface coated with a coating (such as silica) that has low solar absorption and high emissivity at atmospheric windows. The heat storage plate is made of a board with high thermal inertia (such as gypsum board), and the number of layers should be as large as possible. Thermocouples are installed on the outer surface of the radiant panel, between the radiant panel and the heat storage plate, and between the heat storage plates to measure the temperature distribution inside the composite radiant panel. The composite radiant panel is wrapped with an insulation layer (such as polystyrene foam) on all sides and at the bottom to reduce heat exchange between the composite radiant panel and the surrounding environment.

[0097] The composite radiant panel was then placed in the air duct to test the convective heat transfer process on its surface. Based on the measured surface and internal temperatures of the composite radiant panel, the temperature distribution curve t = f(y) along the thickness direction inside the composite radiant panel was fitted, and then the temperature gradient and heat transfer Q at the surface of the radiant panel were calculated. cond Surface convective heat transfer coefficient h conv Finally, the characteristic number correlation Nu=f(Re,Pr) of the convective heat transfer between hot air and the surface of the radiant plate was obtained by fitting.

[0098] Composite radiant panels were placed on the building roof to test the nighttime sky radiation cooling process. Data such as air parameters near the panels and the surface and interior temperatures of the composite radiant panels were obtained. A temperature distribution curve t = f(y) along the thickness direction inside the composite radiant panels was fitted to obtain the temperature gradient and heat transfer Q at the surface of the panels. cond Based on the measured wind speed u and air temperature t near the radiant panel. air Surface temperature t of the radiant plate surface And using the characteristic number correlation Nu=f(Re,Pr) for surface convection heat transfer, the surface convection heat transfer coefficient h can be obtained. conv and surface convection heat transfer Q conv In addition to the thermal conductivity Q of the radiant plate surface cond That is, the cooling capacity of the sky radiation Q. sky Combined with the temperature t air and relative humidity The effective sky temperature t was estimated. sky The equivalent heat transfer coefficient h of sky radiation can be calculated. r .

[0099] Furthermore, based on this, the sky radiation heat transfer coefficient h can be obtained by fitting. r With effective sky temperature t sky Temperature t air Wind speed u, surface temperature t of the radiant plate surface The relationship between parameters such as thermal conductivity λ and emissivity ε is expressed as h. r =f(t) sky ,t air ,u,t surface ,ε,λ).

[0100] Example 2

[0101] Secondly, based on Embodiment 1, this embodiment provides a test system for the equivalent heat transfer coefficient of sky radiation, including a processor and a storage medium;

[0102] The storage medium is used to store instructions;

[0103] The processor is configured to operate according to the instructions to execute the method according to Embodiment 1.

[0104] Example 3

[0105] Thirdly, based on Embodiment 1, this embodiment provides a device, including,

[0106] Memory;

[0107] processor;

[0108] as well as

[0109] Computer programs;

[0110] The computer program is stored in the memory and configured to be executed by the processor to implement the method described in Embodiment 1.

[0111] Example 4

[0112] Fourthly, based on Embodiment 1, this embodiment provides a storage medium on which a computer program is stored, and when the computer program is executed by a processor, it implements the method described in Embodiment 1.

[0113] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0114] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0115] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0116] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0117] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for testing the equivalent heat transfer coefficient of sky radiation, characterized in that, The method includes: The air parameters near the composite radiant roof panel and the surface and internal temperatures of the composite radiant roof panel were obtained from a sky radiation cooling process test. The air parameters included wind speed u and air temperature t. air and relative humidity φ; Based on the measured temperatures of the surface and interior of the composite radiant plate, a temperature distribution curve t = f(y) along the thickness direction inside the composite radiant plate is fitted, and then the temperature gradient and thermal conductivity Q at the surface of the composite radiant plate are calculated. cond ; Based on the wind speed u and temperature t near the composite radiant panel air Surface temperature t of composite radiant panel surface And using the characteristic correlation Nu = f (Re, Pr) for convective heat transfer between hot air and the surface of the composite radiant plate, the surface convective heat transfer coefficient h can be obtained. conv and surface convection heat transfer Q conv Combined with the thermal conductivity Q of the composite radiant plate surface cond Obtain the cooling capacity Q from the sky radiation sky =Q conv + Q cond ; According to temperature t air The effective sky temperature t is estimated by the relative humidity φ. sky According to the cooling capacity Q of sky radiation sky Surface temperature t of composite radiant panel surface and effective sky temperature t sky The equivalent heat transfer coefficient h of sky radiation was calculated. r .

2. The method for testing the equivalent heat transfer coefficient of sky radiation according to claim 1, characterized in that, The characteristic coefficient correlation of the convective heat transfer between the hot air and the surface of the composite radiant plate includes: Nu = f(Re, Pr); In the formula, h conv Let be the convective heat transfer coefficient of the composite radiant plate surface, and l be the length of the composite radiant plate in the airflow direction. The thermal conductivity of the composite radiant panel; u represents the wind speed near the surface of the composite radiant panel. The kinematic viscosity of air; 'a' is the thermal diffusivity of air, determined by the air temperature t. air Sure.

3. The method for testing the equivalent heat transfer coefficient of sky radiation according to claim 1, characterized in that, The method for obtaining the characteristic number correlation of the convective heat transfer between hot air and the surface of the composite radiant plate includes: The temperatures of the composite radiant panel surface and interior, as well as the air temperature near the composite radiant panel surface, were obtained from the convective heat transfer process test within the air duct. With the surface temperature of the composite radiant plate ; Based on the measured temperatures of the surface and interior of the composite radiant plate, a temperature distribution curve along the thickness direction inside the composite radiant plate was obtained by fitting the data. = ( This allows us to determine the temperature gradient and thermal conductivity at the surface of the composite radiant plate. ; Based on thermal conductivity and the air temperature near the surface of the composite radiant panel With the surface temperature of the composite radiant plate The convective heat transfer coefficient of the composite radiant plate surface was obtained. ; Based on the convective heat transfer coefficient of the composite radiant plate surface under different conditions The characteristic number correlation Nu = f (Re, Pr) of the convective heat transfer between hot air and the surface of the composite radiant plate was obtained by fitting.

4. The method for testing the equivalent heat transfer coefficient of sky radiation according to claim 1, characterized in that, Based on the measured temperatures of the composite radiant plate's surface and interior, a temperature distribution curve t = f(y) along the thickness direction inside the composite radiant plate is fitted, and then the temperature gradient and thermal conductivity Q at the surface of the composite radiant plate are calculated. cond ,include: ； In the formula, λ is the thermal conductivity of the composite radiant plate; A is the surface area of ​​the composite radiant plate. This represents the temperature gradient at the surface of the composite radiant plate.

5. The method for testing the equivalent heat transfer coefficient of sky radiation according to claim 3, characterized in that, Based on thermal conductivity and the air temperature near the surface of the composite radiant panel With the surface temperature of the composite radiant plate The convective heat transfer coefficient of the composite radiant plate surface was obtained. include: During the convective heat transfer process on the surface of the composite radiant plate inside the air duct, based on the thermal equilibrium of the composite radiant plate surface, the surface convective heat transfer... Equal to the thermal conductivity at the surface Furthermore, based on the measured air temperature near the surface of the composite radiation plate... With the surface temperature of the composite radiant plate The convective heat transfer coefficient on the surface of the composite radiant plate was obtained. : ； In the formula, The value is equal to the calculated thermal conductivity at the surface of the composite radiant plate. ; The surface area of ​​the composite radiant panel.

6. The method for testing the equivalent heat transfer coefficient of sky radiation according to claim 3, characterized in that, The test of the convective heat transfer process on the surface of the composite radiant plate inside the air duct includes: The composite radiant panel is placed in the air duct, the inner surface of the air duct is a radiant insulation surface, and the air duct is sequentially equipped with a speed-regulating fan, flexible connection, electric heating coil, radiant shielding plate, and reducer. Wind speed and temperature measuring points are set above the composite radiant panel. Turn on the power switch of the electric heating coil. After the electric heating coil has stabilized and heated up, turn on the speed-regulating fan to allow hot air to pass over the surface of the composite radiant plate. Through convection heat transfer, the temperature of the radiant plate and the lower heat storage plate will slowly rise. Collect the temperature of the surface and interior of the composite radiant plate at different times, as well as the air temperature near the surface of the composite radiant plate and the surface temperature of the composite radiant plate.

7. The method for testing the equivalent heat transfer coefficient of sky radiation according to claim 1, characterized in that, The test of the sky radiation cooling process of the roof composite radiant panel includes: The composite radiant panel is placed on the roof of the building, and outdoor air parameter measuring points are set above the composite radiant panel to test the nighttime sky radiation cooling process, and collect air parameters near the composite radiant panel and temperature data of the surface and interior of the composite radiant panel.

8. The method for testing the equivalent heat transfer coefficient of sky radiation according to any one of claims 1-7, characterized in that, The composite radiant panel includes a radiant panel, a heat storage plate assembly, and a thermocouple; The heat storage plate assembly includes multiple layers of heat storage plates stacked along their thickness direction, and thermocouples for measuring temperature are arranged between adjacent heat storage plates. The radiant plate is covered on the heat storage plate assembly. A thermocouple for measuring the surface temperature of the composite radiant plate is provided on the upper surface of the radiant plate. A thermocouple for measuring temperature is arranged between the radiant plate and the heat storage plate assembly.

9. The method for testing the equivalent heat transfer coefficient of sky radiation according to claim 1, characterized in that, According to the cooling capacity of sky radiation Q sky Surface temperature t of composite radiant panel surface and effective sky temperature t sky The equivalent heat transfer coefficient h of sky radiation was calculated. r , include: ； In the formula, The surface area of ​​the composite radiant panel.

10. A testing system for the equivalent heat transfer coefficient of sky radiation, characterized in that, Including processor and storage media; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the method according to any one of claims 1-9.

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