A cooling time estimation method and system suitable for cryogenic environment warehouses

Abstract

The application relates to a cooling time estimation method and system suitable for a low-temperature environment bin. The method comprises the following steps: firstly, acquiring the initial temperature, relative humidity and target temperature of the environment bin; secondly, acquiring the current temperature change value and current cooling time, updating the current temperature according to the current temperature change value, and if the current temperature is greater than a pre-set temperature threshold, calculating a first estimation value according to the current temperature change value and the current cooling time, otherwise, stopping the calculation; thirdly, calculating the remaining cooling time required for the current temperature to reach the target temperature according to the first estimation value; and finally, outputting the remaining cooling time and updating the current temperature to start a new round of estimation. Compared with the prior art, the application has the advantages of obviously improving the accuracy of cooling time estimation in the cold start test of a fuel cell stack, and the like.

Description

Technical Field

[0001] This invention relates to the field of proton exchange membrane fuel cells, and in particular to a method and system for predicting cooling time in a cryogenic environment chamber. Background Technology

[0002] Current cold-start tests of fuel cell stacks require a refrigerated chamber. The temperature inside the chamber is measured by a temperature sensor located above it. However, the required cooling time is significantly affected by environmental conditions, chamber layout, and the operating power of the refrigeration compressor. Even with the same final cooling temperature, the required cooling time can fluctuate considerably and is difficult to accurately predict based on prior experience. Existing research on cold-start testing primarily focuses on predicting cooling temperature, neglecting precise estimation of cooling time. Therefore, accurately predicting the cooling time during fuel cell stack cold-start testing is a problem that needs to be solved in this field. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art by providing a cooling time prediction method and system suitable for low-temperature environment chambers, which can achieve high-precision prediction of cooling time in cold start testing of fuel cell stacks, so as to ensure that the fuel cell system starts within the normal operating temperature range.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] According to a first aspect of the present invention, a method for estimating cooling time suitable for cryogenic environment chambers is provided, comprising the following steps:

[0006] S1, obtain the initial temperature, relative humidity and target temperature of the environmental chamber;

[0007] S2, obtain the current temperature change value and the current cooling time, update the current temperature according to the current temperature change value, if the current temperature is greater than the temperature threshold, calculate the first estimated value according to the current temperature change value and the current cooling time, otherwise stop the calculation. The temperature threshold is preset.

[0008] S3, based on the first estimated value, calculate the remaining cooling time required for the current temperature to reach the target temperature;

[0009] S4, output the remaining cooldown time, and return to S2.

[0010] As a preferred technical solution, the expression for the remaining cooling time is:

[0011]

[0012] In the formula, t_exp represents the remaining cooling time, T0 represents the current temperature, Tini represents the initial temperature, T_last represents the target temperature, k_test represents the first estimated value, P represents the operating power of the refrigeration compressor, η represents the efficiency of the refrigeration compressor, V represents the volume inside the environmental chamber, and R represents the relative humidity inside the environmental chamber before the refrigeration compressor starts working.

[0013] As a preferred technical solution, the expression for the first estimated value is:

[0014]

[0015] In the formula, k_test represents the first estimated value, P represents the operating power of the refrigeration compressor, η represents the efficiency of the refrigeration compressor, t_test represents the current cooling time, dT represents the current temperature change value, V represents the volume inside the environmental chamber, R represents the relative humidity inside the environmental chamber before the refrigeration compressor starts working, T0 represents the current temperature, and Tini represents the initial temperature.

[0016] As a preferred technical solution, the initial temperature of the environmental chamber and the temperature change value are obtained by measuring the temperature sensor.

[0017] As a preferred technical solution, the relative humidity is measured by a humidity sensor.

[0018] According to a second aspect of the present invention, a cooling time estimation system suitable for cryogenic environment chambers is provided. The system includes a data acquisition module, a first estimation calculation module, and a remaining cooling time calculation module. The data acquisition module is signal-connected to the first estimation calculation module, and the first estimation calculation module is signal-connected to the remaining cooling time calculation module.

[0019] The data acquisition module is used to acquire the initial temperature, relative humidity and target temperature of the environmental chamber and send them to the first estimated value calculation module;

[0020] The first estimated value calculation module is used to receive temperature data and humidity data, and obtain the current temperature change value and the current cooling time. It updates the current temperature based on the current temperature change value. If the current temperature is greater than the temperature threshold, it calculates the first estimated value based on the current temperature change value and the current cooling time and sends it to the remaining cooling time calculation module. Otherwise, it stops the calculation. The temperature threshold is preset.

[0021] The remaining cooling time calculation module is used to receive the first estimated value, calculate the remaining cooling time required for the current temperature to reach the target temperature based on the first estimated value, output the remaining cooling time, and send the current temperature to the first estimated value calculation module.

[0022] As a preferred technical solution, the expression for the remaining cooling time is:

[0023]

[0024] In the formula, t_exp represents the remaining cooling time, T0 represents the current temperature, Tini represents the initial temperature, T_last represents the target temperature, k_test represents the first estimated value, P represents the operating power of the refrigeration compressor, η represents the efficiency of the refrigeration compressor, V represents the volume inside the environmental chamber, and R represents the relative humidity inside the environmental chamber before the refrigeration compressor starts working.

[0025] As a preferred technical solution, the expression for the first estimated value is:

[0026]

[0027] In the formula, k_test represents the first estimated value, P represents the operating power of the refrigeration compressor, η represents the efficiency of the refrigeration compressor, t_test represents the current cooling time, dT represents the current temperature change value, V represents the volume inside the environmental chamber, R represents the relative humidity inside the environmental chamber before the refrigeration compressor starts working, T0 represents the current temperature, and Tini represents the initial temperature.

[0028] As a preferred technical solution, the initial temperature of the environmental chamber and the temperature change value are obtained by measuring the temperature sensor.

[0029] As a preferred technical solution, the relative humidity is measured by a humidity sensor.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. When estimating the remaining cooling time to reach the target temperature, this invention considers the initial temperature and temperature change of the environmental chamber, and constantly monitors the temperature change of the environmental chamber, that is, it considers the heat exchange effect between the inner wall of the environmental chamber and the external environment, thereby improving the accuracy of cooling time estimation.

[0032] 2. When estimating the remaining cooling time to reach the target temperature, this invention takes into account the relative humidity of the ambient chamber. Changes in humidity affect the water vapor content, that is, the enthalpy of water vapor in the air inside the ambient chamber is taken into account, which further improves the accuracy of the cooling time estimation. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the method in Embodiment 1 of the present invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0035] Example 1

[0036] like Figure 1 As shown, this embodiment provides a method for estimating the cooling time of a cryogenic environment chamber, including the following steps:

[0037] Step S1: Use a temperature sensor to measure the initial temperature Tini in the environmental chamber, use a humidity sensor to measure the relative humidity R in the environmental chamber before the refrigeration compressor starts working, and set the final cooling temperature to be reached, i.e., the target temperature T_last. At this time, the current temperature T0 = Tini.

[0038] Step S2: The refrigeration compressor starts working. After a period of time, the current temperature change value dT is measured using a temperature sensor. The current temperature T0 is updated based on the current temperature change value dT, i.e., T0 = T0 - dT. The current cooling time t_test is recorded. If the current temperature T0 is greater than the preset temperature threshold T1, the first estimated value is calculated based on the current temperature change value dT and the current cooling time t_test. Otherwise, the calculation is stopped.

[0039] The expression for the first estimated value is:

[0040]

[0041] In the above formula, k_test represents the first estimated value, P represents the operating power of the refrigeration compressor in W, η represents the efficiency of the refrigeration compressor, and V represents the volume inside the environmental chamber in m³. 3 .

[0042] Step S3: Based on the first estimated value k_test, calculate and output the remaining cooling time required for the current temperature to reach the target temperature T_last. The expression for the remaining cooling time is:

[0043]

[0044] In the above formula, t_exp represents the remaining cooling time; in formulas (1) and (2), dT, T0, and Tini are all temperature values ​​in °C.

[0045] Step S4: Output the remaining cooldown time t_exp and return to step S2.

[0046] Example 2

[0047] This embodiment provides a cooling time estimation system suitable for a cryogenic environment chamber, which can implement the method in Embodiment 1. The system includes a data acquisition module, a first estimate calculation module, and a remaining cooling time calculation module. The data acquisition module is signal-connected to the first estimate calculation module, and the first estimate calculation module is signal-connected to the remaining cooling time calculation module. Specifically, the data acquisition module acquires the initial temperature, relative humidity, and target temperature of the environment chamber and sends them to the first estimate calculation module. The first estimate calculation module receives temperature and humidity data, acquires the current temperature change value and the current cooling time, updates the current temperature based on the current temperature change value, and if the current temperature is greater than a preset temperature threshold, calculates the first estimate based on the current temperature change value and the current cooling time and sends it to the remaining cooling time calculation module; otherwise, the calculation stops. The remaining cooling time calculation module receives the first estimate value, calculates the remaining cooling time required for the current temperature to reach the target temperature based on the first estimate value, outputs the remaining cooling time, and sends the current temperature to the first estimate calculation module. Those skilled in the art will understand that, for ease of description and brevity, the specific working processes of the aforementioned modules can be referred to the corresponding processes in Embodiment 1, and will not be repeated here.

[0048] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for estimating a cooling time of a fuel cell low temperature environment chamber, characterized by, The method comprises the following steps: S1, obtaining an initial temperature, a relative humidity and a target temperature of an environment warehouse; S2, obtaining a current temperature change value and a current cooling time, updating a current temperature according to the current temperature change value, and if the current temperature is greater than a temperature threshold, calculating a first estimation value according to the current temperature change value and the current cooling time, otherwise stopping the calculation, wherein the temperature threshold is preset; S3, calculating a remaining cooling time required for the current temperature to reach the target temperature according to the first estimation value; S4, outputting the remaining cooling time and returning to S2; The expression of the remaining cooling time is: In the formula, t_exp represents the remaining cooling time, T0 represents the current temperature, Tini represents the initial temperature, Tlast represents the target temperature, k_test represents the first estimation value, P represents the operating power of a refrigeration compressor, η represents the efficiency of the refrigeration compressor, V represents the volume in the environment warehouse, and R represents the relative humidity in the environment warehouse before the refrigeration compressor works; The expression of the first estimation value is: In the formula, k_test represents the first estimation value, P represents the operating power of a refrigeration compressor, η represents the efficiency of the refrigeration compressor, t_test represents the current cooling time, dT represents the current temperature change value, V represents the volume in the environment warehouse, R represents the relative humidity in the environment warehouse before the refrigeration compressor works, T0 represents the current temperature, and Tini represents the initial temperature.

2. The cooling time estimation method for a fuel cell cryogenic environment chamber according to claim 1, characterized by, The initial temperature of the environment warehouse and the temperature change value are measured by a temperature sensor.

3. The cooling time estimation method for a fuel cell cryogenic environment chamber according to claim 1, wherein, The relative humidity is measured by a humidity sensor.

4. A cooling time estimation system for a fuel cell cryogenic environment chamber, comprising: The system comprises a data acquisition module, a first estimation value calculation module and a remaining cooling time calculation module, the data acquisition module is signal connected with the first estimation value calculation module, the first estimation value calculation module is signal connected with the remaining cooling time calculation module, The data acquisition module is used to obtain the initial temperature, the relative humidity and the target temperature of the environment warehouse and send them to the first estimation value calculation module; The first estimation value calculation module is used to receive temperature data and humidity data, obtain a current temperature change value and a current cooling time, update a current temperature according to the current temperature change value, if the current temperature is greater than a temperature threshold, calculate a first estimation value according to the current temperature change value and the current cooling time and send it to the remaining cooling time calculation module, otherwise stop the calculation, wherein the temperature threshold is preset; The remaining cooling time calculation module is used to receive the first estimation value, calculate a remaining cooling time required for the current temperature to reach the target temperature according to the first estimation value, output the remaining cooling time and send the current temperature to the first estimation value calculation module; The expression of the remaining cooling time is: In the formula, t_exp represents the remaining cooling time, T0 represents the current temperature, Tini represents the initial temperature, T_last represents the target temperature, k_test represents the first estimated value, P represents the operating power of the refrigeration compressor, η represents the efficiency of the refrigeration compressor, V represents the volume of the environment chamber, and R represents the relative humidity in the environment chamber before the refrigeration compressor is operated. The expression of the first estimated value is: In the formula, k_test represents the first estimated value, P represents the operating power of the refrigeration compressor, η represents the efficiency of the refrigeration compressor, t_test represents the current cooling time, dT represents the current temperature change value, V represents the volume of the environment chamber, R represents the relative humidity in the environment chamber before the refrigeration compressor is operated, T0 represents the current temperature, and Tini represents the initial temperature.

5. The cooling time estimation system for a fuel cell cryogenic environment chamber according to claim 4, wherein The initial temperature of the environment chamber and the temperature change value are measured by a temperature sensor.

6. The cooling time estimation system for a fuel cell cryogenic environment chamber according to claim 4, wherein The relative humidity is measured by a humidity sensor.

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