Heat calculation method of solar water heater

Abstract

The invention provides a heat calculation method for a solar water heater, and the method comprises the steps: obtaining the electric energy heat and solar energy heat of the solar water heater; variable factor coefficients corresponding to the electric energy heat and the solar energy heat are determined; and performing weighted calculation on the electric energy heat, the solar energy heat and the corresponding variable factor coefficients to obtain a weighted sum, and dividing the weighted sum by the sum of the two variable factor coefficients to obtain the total heat of the solar water heater.

Description

Technical Field

[0001] The present application relates to the technical field of water heaters, and in particular to a heat calculation method for a solar water heater. Background Art

[0002] Water heaters are one of the common household appliances in our daily life. They can provide us with hot water to meet our daily needs of bathing, washing dishes, etc. The working principle of water heaters is to use electrical energy to convert thermal energy into hot water. In the design and selection process of water heaters, it is necessary to calculate the electric heat of water heaters to ensure that they can meet the user's hot water needs. Summary of the invention

[0003] In view of this, the purpose of the present application is to at least provide a heat calculation method for a solar water heater, so as to improve the heat calculation accuracy of the solar water heater, and thereby improve the estimation accuracy of the heating time required for the solar water heater.

[0004] This application mainly includes the following aspects: In a first aspect, an embodiment of the present application provides a method for calculating the heat of a solar water heater, the method comprising: Obtain electrical heat and solar heat from solar water heaters; Determine the variable factor coefficients corresponding to the electric energy heat and the solar energy heat respectively; The electric energy heat, the solar energy heat and their corresponding variable factor coefficients are weighted to obtain a weighted sum, and the weighted sum is divided by the sum of the two variable factor coefficients to obtain the total heat of the solar water heater.

[0005] In a possible implementation, obtaining electric energy heat from a solar water heater includes: The electric energy heat is calculated by the formula Q1= (cm△t1+cm△t2+…+cm△tn); Wherein, Q1 is the electric energy heat, c represents the specific heat capacity, m represents the mass, and Δtn is the temperature difference in the nth time period.

[0006] In a possible implementation, obtaining solar energy from a solar water heater includes: The solar heat is calculated by the formula Q2= (cs△t1+cs△t2+…+cs△tn); Wherein, Q2 is the solar heat, c represents the specific heat capacity, s represents the heat absorption area, and Δtn is the temperature difference in the nth time period.

[0007] In a possible implementation, the method further includes: Obtain the temperature values ​​of the three paths corresponding to the first time point and the last time point in the nth time period respectively; The temperature values ​​of the three paths at the first time point are averaged to obtain a first temperature value, and the temperature values ​​of the three paths at the last time point are averaged to obtain a second temperature value; The first temperature value and the second temperature value are calculated to obtain a temperature difference in the nth time period.

[0008] In a possible implementation manner, determining the variable factor coefficients corresponding to the electric energy heat and the solar energy heat respectively includes: Based on the water tank capacity, solar panel absorption efficiency and heating efficiency of the solar water heater, the relationship between the change in hot water temperature per unit time and the change in the electric energy heat and the solar energy heat is calculated; Determine the variable factor coefficient of the electric energy heat according to the relationship between the change of the hot water temperature and the change of the electric energy heat; The variable factor coefficient of the solar energy heat is determined according to the relationship between the change of the hot water temperature and the change of the solar energy heat.

[0009] In a possible implementation, the calculation of the relationship between the change in hot water temperature per unit time and the corresponding change in the electric energy heat and the solar energy heat, respectively, based on the water tank capacity, solar panel absorption efficiency, and heating efficiency of the solar water heater includes: Acquire historical data of the solar water heater, wherein the historical data includes water tank capacity, solar panel absorption efficiency, heating efficiency, and hot water temperature change per unit time; Perform linear fitting based on the historical data to obtain a first linear fitting formula and a second linear fitting formula; The first linear fitting formula is used to obtain the relationship between the change in hot water temperature per unit time and the change in the electric energy heat; the second linear fitting formula is used to obtain the relationship between the change in hot water temperature per unit time and the change in solar energy heat.

[0010] In a possible implementation manner, determining the variable factor coefficient of the electric energy heat according to the relationship between the change in the hot water temperature and the change in the electric energy heat includes: The variable factor coefficient of the electric energy heat is determined according to the linear fitting coefficient in the first linear fitting formula.

[0011] In a possible implementation manner, determining the variable factor coefficient of the solar energy heat according to the relationship between the change in the hot water temperature and the change in the solar energy heat includes: The variable factor coefficient of the solar heat is determined according to the linear fitting coefficient in the second linear fitting formula.

[0012] In a second aspect, an embodiment of the present application further provides a heat calculation device for a solar water heater, the device comprising: An acquisition module, used for acquiring electric energy heat and solar energy heat of the solar water heater; A determination module, used to determine the variable factor coefficients corresponding to the electric energy heat and the solar energy heat respectively; The calculation module is used to obtain a weighted sum by weighted calculation of the electric energy heat, the solar energy heat and their corresponding variable factor coefficients, and to obtain the total heat of the solar water heater by dividing the weighted sum by the sum of the two variable factor coefficients.

[0013] In a third aspect, an embodiment of the present application further provides a solar water heater, which comprises: a heat pump unit, a water tank, a processor and a memory; the memory stores a computer program; when the processor executes the computer program stored in the memory, the heat calculation method of the solar water heater is implemented to control the heat pump unit; the heat pump unit is used to heat the water in the water tank.

[0014] In a fourth aspect, an embodiment of the present application further provides an electronic device, comprising: a processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the memory communicate through the bus, and the machine-readable instructions are executed by the processor to execute the steps of the heat calculation method for a solar water heater described in the first aspect or any possible implementation manner of the first aspect.

[0015] In a fifth aspect, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of heat calculation and control of the solar water heater described in the first aspect or any possible implementation manner of the first aspect are executed.

[0016] The embodiment of the present application provides a method for calculating the heat of a solar water heater. First, the electric heat and solar heat of the solar water heater are obtained; then the variable factor coefficients corresponding to the electric heat and the solar heat are determined; finally, the electric heat, the solar heat and their corresponding variable factor coefficients are weighted to obtain a weighted sum, and the weighted sum is divided by the sum of the two variable factor coefficients to obtain the total heat of the solar water heater. Thus, the heat calculation of the solar water heater is realized through the present application, so that the heat calculation accuracy of the solar water heater can be improved through the present application, and then the estimation accuracy of the heating time required by the solar water heater can be improved.

[0017] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A flow chart showing a method for calculating heat of a solar water heater provided in an embodiment of the present application is shown; Figure 2 A structural block diagram of a heat calculation device for a solar water heater provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0020] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowchart can be implemented out of sequence, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art, under the guidance of the content of the present application, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0021] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0022] See also Figure 1 , Figure 1 This is a flow chart of a method for calculating the heat of a solar water heater provided in an embodiment of the present application. Figure 1As shown, the embodiment of the present application provides a method for calculating the heat of a solar water heater, the method comprising the following steps: S101, obtaining electric energy heat and solar energy heat of the solar water heater.

[0023] In this embodiment, the acquisition of electric energy heat of the solar water heater includes: calculating the electric energy heat by the formula Q1= (cm△t1+cm△t2+…+cm△tn); wherein Q1 is the electric energy heat, c represents the specific heat capacity, m represents the mass, and △tn is the temperature difference in the nth time period. Furthermore, after calculating the electric energy heat, this embodiment corrects and compares the electric energy consumption W by the heating tube power and the running time. Ignoring the case of energy loss, Q≈W=PT, W refers to the power, P refers to the heating tube power, and T refers to the start-up running time of the electric heating tube.

[0024] In this embodiment, the solar heat of the solar water heater is obtained, including: calculating the solar heat by formula Q2= (cs△t1+cs△t2+…+cs△tn); wherein Q2 is the solar heat, c represents the specific heat capacity, s represents the heat absorption area, and △tn is the temperature difference in the nth time period. The length of the time period can be set according to actual needs, such as 5 minutes, 10 minutes, 15 minutes, etc., and this embodiment does not specifically limit this.

[0025] It should be noted that the method for obtaining the temperature difference in the present application is: obtaining the three-way temperature values ​​corresponding to the first time point and the last time point in the nth time period; averaging the three-way temperature values ​​at the first time point to obtain the first temperature value, averaging the three-way temperature values ​​at the last time point to obtain the second temperature value; calculating the first temperature value and the second temperature value to obtain the temperature difference of the nth time period. Among them, the three-way temperature values ​​are the temperature values ​​of three different positions inside the solar water heater. For example, in this embodiment, the temperature value is obtained by collecting three-way water temperature (T1, T2, T3), the collection medium is a thermistor, the collection frequency is 3 times / minute, and the collected values ​​are converted into an RT parameter comparison table to form an observable temperature value and a calculable temperature value, so as to calculate the temperature difference of the nth time period according to the obtained temperature value.

[0026] For example, the temperature values ​​of the three channels at the first time point are 10°C, 12°C, and 11°C, and the first temperature value obtained by averaging is 11°C. The temperature values ​​of the three channels at the last time point are 12°C, 13°C, and 14°C, and the second temperature value obtained by calculation is 13°C, and the final temperature difference is 3°C.

[0027] S102, determining the variable factor coefficients corresponding to the electric energy heat and the solar energy heat respectively.

[0028] Among them, the variable factor coefficients corresponding to electric heat and solar heat are set based on comprehensive factors such as water tank capacity, solar panel absorption efficiency, and heating efficiency, and the relationship between the change in hot water temperature and the change in total hot water volume per unit time is calculated.

[0029] Specifically, this embodiment detects the start-up time of the circulation pump and the temperature rise, and replaces the start-up of the circulation pump with electric heating. This is understood as the variable factor coefficient is a ratio and also a variable. In the experimental stage, it is measured that the temperature rises by 10 degrees when the circulation pump is turned on for 1 hour, and the temperature rises by 10 degrees when the electric heating starts for 10 minutes. A variable value is given according to this ratio. Finally, in the case of software logic failure, it will be considered to fix a variable factor, such as setting the variable factor coefficient to 10, or manually calibrating the variable factor coefficient.

[0030] In an optional embodiment provided by the application, the determining of the variable factor coefficients corresponding to the electric energy heat and the solar energy heat respectively includes: S1021, based on the water tank capacity, solar panel absorption efficiency and heating efficiency of the solar water heater, calculating the change relationship between the hot water temperature change per unit time and the electric energy heat and the solar energy heat respectively.

[0031] Specifically, the calculation of the change relationship between the hot water temperature change per unit time and the electric energy heat and the solar energy heat respectively based on the water tank capacity, solar panel absorption efficiency and heating efficiency of the solar water heater includes: acquiring historical data of the solar water heater, the historical data including the water tank capacity, solar panel absorption efficiency, heating efficiency and the hot water temperature change per unit time; performing linear fitting according to the historical data to obtain a first linear fitting formula and a second linear fitting formula; obtaining the change relationship between the hot water temperature change per unit time and the electric energy heat through the first linear fitting formula; obtaining the change relationship between the hot water temperature change per unit time and the solar energy heat through the second linear fitting formula.

[0032] It should be noted that the basic principle of solar water heaters is to use sunlight to shine on the collector, convert solar energy into heat energy through the collector, and then transfer the heat energy to the water tank through the pipe, and finally achieve the purpose of heating water. When calculating the water temperature, the following factors need to be considered: collector area and design parameters (such as collector type, material, etc.); solar radiation intensity and direction (such as season, weather, etc.); hot water tank volume and design parameters (such as hot water tank shape, size, etc.); pipeline length and design parameters (such as pipeline diameter, insulation layer, etc.).

[0033] Based on the above factors, some empirical formulas are used to calculate the water temperature of the solar water heater: the relationship formula between light intensity and temperature: I = k * T, where I is the light intensity, k is a constant, and T is the ambient temperature; the collector absorption coefficient formula: α = η * ε, where α is the heat absorption coefficient of the collector, η is the solar radiation coefficient, and ε is the absorption coefficient of the collector; the hot water tank heat dissipation coefficient formula: β = α * C, where β is the heat dissipation coefficient of the hot water tank, and C is the specific heat capacity of the hot water tank.

[0034] Assume that there is a collector area of ​​2 square meters, the solar radiation intensity is 500 watts / square meter, the hot water tank volume is 50 liters, and the pipe length is 10 meters. According to the above formula, the following calculation is performed: The relationship between light intensity and temperature is: I = k * T, where k is a constant and T is temperature. The value of k can be obtained through experimental measurement, and then substituted into the formula to calculate the light intensity I.

[0035] The formula for the heat absorption coefficient of the collector is: α = η * ε, where η is the solar radiation coefficient and ε is the absorption coefficient of the collector. Based on empirical data, we can get η to be approximately 0.7 and ε to be approximately 0.9. Therefore, α = η * ε = 0.7 * 0.9 = 0.63.

[0036] The heat dissipation coefficient formula of the hot water tank is: β = α * C, where β is the heat dissipation coefficient of the hot water tank and C is the specific heat capacity of the hot water tank. According to empirical data, we can get C to be about 4.2 kJ / kg·°C. Therefore, β = α * C = 0.63 * 4.2 = 2.64.

[0037] Assuming that the total solar radiation energy received by the collector is G (W / ㎡), the heat absorbed by the collector is G×ηc. At the same time, the hot water tank will dissipate heat to the outside due to the temperature difference. Assuming the initial temperature of the water tank is T0 and the ambient temperature is Ta, the heat dissipation of the water tank per hour is (T0-Ta)×ηL.

[0038] Assuming that within a certain time period ΔT, all the heat absorbed by the collector is used to heat water, and other heat losses (such as heat loss in the pipeline, etc.) are not considered, the amplitude of water temperature rise Δt within this time period can be calculated by the following formula: Δt = (G×ηc×ΔT) / (mc) - (T0-Ta)×ηL×ΔT / m, where m is the mass of water in the water tank (kg), and c is the specific heat capacity of water [J / (kg·℃)].

[0039] Since the change of water temperature will affect the heat dissipation of the water tank, the above formula is a nonlinear equation about ΔT. It can be solved by iterative method or numerical method to obtain the curve of water temperature change over time. In summary, calculating the temperature of the solar water heater based on the heat absorption coefficient of the collector and the heat dissipation coefficient of the hot water tank is a problem involving multiple variables and complex heat transfer processes, which requires the establishment of a reasonable mathematical model and the use of appropriate numerical methods to solve it.

[0040] S1022, determining the variable factor coefficient of the electric energy heat according to the relationship between the change of the hot water temperature and the change of the electric energy heat.

[0041] Specifically, determining the variable factor coefficient of the electric energy heat according to the relationship between the change in the hot water temperature and the change in the electric energy heat includes: determining the variable factor coefficient of the electric energy heat according to the linear fitting coefficient in the first linear fitting formula.

[0042] S1023, determining a variable factor coefficient of the solar energy heat according to a relationship between a change in the hot water temperature and a change in the solar energy heat.

[0043] Specifically, determining the variable factor coefficient of the solar energy heat according to the relationship between the change in the hot water temperature and the change in the solar energy heat includes: determining the variable factor coefficient of the solar energy heat according to the linear fitting coefficient in the second linear fitting formula.

[0044] S103, performing weighted calculation on the electric energy heat, the solar energy heat and their corresponding variable factor coefficients to obtain a weighted sum, and dividing the weighted sum by the sum of the two variable factor coefficients to obtain the total heat of the solar water heater.

[0045] Specifically, the total heat of the solar water heater Qtotal = (i*Q1+j*Q2) / (i+j), where Q1 is electric heat, Q2 is solar heat, i is the variable factor coefficient of electric heat, and j is the variable factor coefficient of solar heat. That is, the present embodiment calculates the total heat of the solar water heater by weighted average, where the weights i and j are selected according to the variable factor coefficient, which is set based on comprehensive factors such as water tank capacity, solar panel absorption efficiency, and heating efficiency, and calculates the relationship between the change in hot water temperature and the change in the total amount of hot water per unit time.

[0046] The embodiment of the present application provides a method for calculating the heat of a solar water heater. First, the electric heat and solar heat of the solar water heater are obtained; then the variable factor coefficients corresponding to the electric heat and the solar heat are determined; finally, the electric heat, the solar heat and their corresponding variable factor coefficients are weighted to obtain a weighted sum, and the weighted sum is divided by the sum of the two variable factor coefficients to obtain the total heat of the solar water heater. Thus, the heat calculation of the solar water heater is realized through the present application, so that the heat calculation accuracy of the solar water heater can be improved through the present application, and then the estimation accuracy of the heating time required by the solar water heater can be improved.

[0047] In the case of dividing each functional module into corresponding functional modules, Figure 2 A possible schematic diagram of the composition of the heat calculation device of the solar water heater involved in the above and embodiments is shown. Figure 2 As shown, the heat calculation device of the solar water heater may include: An acquisition module 21 is used to acquire electric energy heat and solar energy heat of the solar water heater; A determination module 22, used to determine the variable factor coefficients corresponding to the electric energy heat and the solar energy heat respectively; The calculation module 23 is used to obtain a weighted sum by performing weighted calculation on the electric energy heat, the solar energy heat and their corresponding variable factor coefficients, and to obtain the total heat of the solar water heater by dividing the weighted sum by the sum of the two variable factor coefficients.

[0048] In a possible implementation, the acquisition module 21 is specifically configured to: The electric energy heat is calculated by the formula Q1= (cm△t1+cm△t2+…+cm△tn); Wherein, Q1 is the electric energy heat, c represents the specific heat capacity, m represents the mass, and Δtn is the temperature difference in the nth time period.

[0049] In a possible implementation, the acquisition module 21 is specifically configured to: The solar heat is calculated by the formula Q2= (cs△t1+cs△t2+…+cs△tn); Wherein, Q2 is the solar heat, c represents the specific heat capacity, s represents the heat absorption area, and Δtn is the temperature difference in the nth time period.

[0050] In a possible implementation manner, the acquisition module 21 is further configured to: Obtain the temperature values ​​of the three paths corresponding to the first time point and the last time point in the nth time period respectively; The temperature values ​​of the three paths at the first time point are averaged to obtain a first temperature value, and the temperature values ​​of the three paths at the last time point are averaged to obtain a second temperature value; The first temperature value and the second temperature value are calculated to obtain a temperature difference in the nth time period.

[0051] In a possible implementation, the determination module 22 is specifically configured to: Based on the water tank capacity, solar panel absorption efficiency and heating efficiency of the solar water heater, the relationship between the change in hot water temperature per unit time and the change in the electric energy heat and the solar energy heat is calculated; Determine the variable factor coefficient of the electric energy heat according to the relationship between the change of the hot water temperature and the change of the electric energy heat; The variable factor coefficient of the solar energy heat is determined according to the relationship between the change of the hot water temperature and the change of the solar energy heat.

[0052] In a possible implementation, the determination module 22 is specifically configured to: Acquire historical data of the solar water heater, wherein the historical data includes water tank capacity, solar panel absorption efficiency, heating efficiency, and hot water temperature change per unit time; Perform linear fitting based on the historical data to obtain a first linear fitting formula and a second linear fitting formula; The first linear fitting formula is used to obtain the relationship between the change in hot water temperature per unit time and the change in the electric energy heat; the second linear fitting formula is used to obtain the relationship between the change in hot water temperature per unit time and the change in solar energy heat.

[0053] In a possible implementation, the determination module 22 is specifically configured to: The variable factor coefficient of the electric energy heat is determined according to the linear fitting coefficient in the first linear fitting formula.

[0054] In a possible implementation, the determination module 22 is specifically configured to: The variable factor coefficient of the solar heat is determined according to the linear fitting coefficient in the second linear fitting formula.

[0055] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In the several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0056] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0057] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0058] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program codes.

[0059] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for calculating the heat of a solar water heater, characterized in that: The method comprises: Obtain electrical heat and solar heat from solar water heaters; Determine the variable factor coefficients corresponding to the electric energy heat and the solar energy heat respectively; A weighted sum is obtained by weighting the electric energy heat, the solar energy heat and their corresponding variable factor coefficients, and the weighted sum is divided by the sum of the two variable factor coefficients to obtain the total heat of the solar water heater; The determining of the variable factor coefficients corresponding to the electric energy heat and the solar energy heat respectively includes: Based on the water tank capacity, solar panel absorption efficiency and heating efficiency of the solar water heater, the relationship between the change in hot water temperature per unit time and the change in the electric energy heat and the solar energy heat is calculated; Determine the variable factor coefficient of the electric energy heat according to the relationship between the change of the hot water temperature and the change of the electric energy heat; The variable factor coefficient of the solar energy heat is determined according to the relationship between the change of the hot water temperature and the change of the solar energy heat.

2. The method according to claim 1, characterized in that The method of obtaining electric energy and heat from a solar water heater comprises: The electric energy heat is calculated by the formula Q1= (cm△t1+cm△t2+…+cm△tn); Wherein, Q1 is the electric energy heat, c represents the specific heat capacity, m represents the mass, and Δtn is the temperature difference in the nth time period.

3. The method according to claim 2, characterized in that The method of obtaining solar energy heat from a solar water heater comprises: The solar heat is calculated by the formula Q2= (cs△t1+cs△t2+…+cs△tn); Wherein, Q2 is the solar heat, c represents the specific heat capacity, s represents the heat absorption area, and Δtn is the temperature difference in the nth time period.

4. The method according to claim 3, characterized in that: The method further comprises: Obtain the temperature values ​​of the three paths corresponding to the first time point and the last time point in the nth time period respectively; The temperature values ​​of the three paths at the first time point are averaged to obtain a first temperature value, and the temperature values ​​of the three paths at the last time point are averaged to obtain a second temperature value; The first temperature value and the second temperature value are calculated to obtain a temperature difference in the nth time period.

5. The method according to claim 1, characterized in that The calculation of the relationship between the change in hot water temperature per unit time and the corresponding change in the electric energy heat and the solar energy heat respectively based on the water tank capacity, solar panel absorption efficiency and heating efficiency of the solar water heater includes: Acquire historical data of the solar water heater, wherein the historical data includes water tank capacity, solar panel absorption efficiency, heating efficiency, and hot water temperature change per unit time; Perform linear fitting based on the historical data to obtain a first linear fitting formula and a second linear fitting formula; The first linear fitting formula is used to obtain the relationship between the change in hot water temperature per unit time and the change in the electric energy heat; the second linear fitting formula is used to obtain the relationship between the change in hot water temperature per unit time and the change in solar energy heat.

6. The method according to claim 5, characterized in that The variable factor coefficient of the electric energy heat is determined according to the relationship between the change of the hot water temperature and the change of the electric energy heat, including: The variable factor coefficient of the electric energy heat is determined according to the linear fitting coefficient in the first linear fitting formula.

7. The method according to claim 5, characterized in that The step of determining the variable factor coefficient of the solar energy heat according to the relationship between the change in the hot water temperature and the change in the solar energy heat comprises: The variable factor coefficient of the solar heat is determined according to the linear fitting coefficient in the second linear fitting formula.

8. A heat calculation device for a solar water heater, characterized in that: The device comprises: An acquisition module, used for acquiring electric energy heat and solar energy heat of the solar water heater; A determination module, used to determine the variable factor coefficients corresponding to the electric energy heat and the solar energy heat respectively; A calculation module, used for performing weighted calculation on the electric energy heat, the solar energy heat and their corresponding variable factor coefficients to obtain a weighted sum, and dividing the weighted sum by the sum of the two variable factor coefficients to obtain the total heat of the solar water heater; The determination module is specifically used for: Based on the water tank capacity, solar panel absorption efficiency and heating efficiency of the solar water heater, the relationship between the change in hot water temperature per unit time and the change in the electric energy heat and the solar energy heat is calculated; Determine the variable factor coefficient of the electric energy heat according to the relationship between the change of the hot water temperature and the change of the electric energy heat; The variable factor coefficient of the solar energy heat is determined according to the relationship between the change of the hot water temperature and the change of the solar energy heat.

9. A solar water heater, characterized in that: The solar water heater comprises: a heat pump unit, a water tank, a processor and a memory; the memory stores a computer program; when the processor executes the computer program stored in the memory, the heat calculation method of the solar water heater described in any one of claims 1 to 7 is implemented to control the heat pump unit; the heat pump unit is used to heat the water in the water tank.

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