A method and system for evaluating thermal comfort based on local standard effective temperature

Abstract

The application relates to the technical field of thermal comfort evaluation, and particularly discloses a thermal comfort evaluation method and system based on a local standard effective temperature. In a set standard environment, when the total heat exchange amount between a certain local part of a human body and the standard environment is equal to the total heat exchange amount of the part in an actual environment, the air temperature of the standard environment is the local standard effective temperature of the part. The calculation method is as follows: obtaining the local physiological parameters of a target body part in an actual environment; defining a standard environment; constructing an energy balance equation based on the local physiological parameters of the target body part in the actual environment and the heat loss conservation principle, the energy balance equation being used to describe the relationship that the total heat dissipation amount of the target body part in the actual environment is equal to the theoretical total heat dissipation amount in the defined standard environment; and solving the energy balance equation to obtain the local standard effective temperature of the part. The application effectively fills the technical blank of the quantitative evaluation of local thermal comfort in a non-uniform environment.

Description

Technical Field

[0001] This invention relates to the field of thermal comfort evaluation technology, and in particular to a thermal comfort evaluation method and system based on local standard effective temperature. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Standard effective temperature is a comprehensive evaluation index reflecting the overall thermal sensation of the human body, based on a human physiological response model and taking into account factors such as metabolic rate, clothing thermal resistance, ambient temperature and humidity, and wind speed. However, in non-uniform thermal environments such as localized heating, air conditioning, and radiant heating, the physiological responses of different parts of the body vary significantly. For example, when driving in summer, if the air conditioning is blowing directly on your arm, your arm will feel very cold, but other parts of your body will feel just right; in a cold room, if you are near a radiator, your hands will feel warm, but your feet will still be cold.

[0004] In the aforementioned non-uniform thermal environments, traditional whole-body effective temperature indices cannot accurately describe local thermal states. Currently, there is no method for calculating local standard effective temperature that considers the total heat exchange between the human body and the environment. This makes it difficult to convert the local physiological parameters output by the model into intuitive and comparable temperature indices, thus limiting their engineering application in thermal comfort evaluation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a thermal comfort evaluation method and system based on local standard effective temperature, which can accurately reflect the total heat exchange state between the local human body and the microenvironment. This solves the problem that local physiological parameters are difficult to directly use for engineering evaluation in existing technologies and fills the technical gap in quantitative evaluation of local thermal comfort in non-uniform environments.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: Firstly, a method for evaluating thermal comfort based on local standard effective temperature is provided, including: Obtain local physiological parameters of the target body part in a real environment; Define a standard environment; An energy balance equation is constructed based on the local physiological parameters of the target body part in the actual environment and the principle of heat loss conservation. The energy balance equation is used to describe the relationship between the total heat dissipation of the target body part in the actual environment and the theoretical total heat dissipation in the defined standard environment. Solving the energy balance equation yields the local standard effective temperature of the affected area. The local standard effective temperature refers to the air temperature of the standard environment at which the total heat exchange between a local part of the human body and the standard environment equals the total heat exchange of that part in the actual environment.

[0007] Secondly, a thermal comfort evaluation system based on local standard effective temperature is provided, including: The local physiological parameter acquisition module is used to acquire the local physiological parameters of the target body part in the actual environment. The standard environment definition module is used to define the standard environment; An energy balance equation construction module is used to construct an energy balance equation based on the local physiological parameters and the principle of heat loss conservation. The energy balance equation is used to describe the relationship between the total heat dissipation of the target body part in the actual environment and the theoretical total heat dissipation in the standard environment. The local standard effective temperature calculation module is used to solve the energy balance equation to obtain the local standard effective temperature of the part. The local standard effective temperature refers to the air temperature of the standard environment when the total heat exchange between a local part of the human body and the standard environment is equal to the total heat exchange of the part in the actual environment.

[0008] Thirdly, an electronic device is also provided, comprising: Memory, used for non-transitory storage of computer-readable instructions; and Processor, for executing the computer-readable instructions, When the computer-readable instructions are executed by the processor, they perform the method described in the first aspect above.

[0009] Fourthly, a storage medium is also provided for non-transitory storage of computer-readable instructions, wherein the method described in the first aspect is performed when the non-transitory computer-readable instructions are executed by a computer.

[0010] The above technical solution has the following advantages or beneficial effects: This invention proposes the concept of local standard effective temperature and provides a corresponding calculation method, which can truly reflect the total heat exchange state between the local human body and the microenvironment. It solves the problem that local physiological parameters are difficult to use directly for engineering evaluation in the prior art and fills the technical gap in the quantitative evaluation of local thermal comfort in non-uniform environments.

[0011] The evaluation index and calculation method for evaluating local thermal comfort proposed in this invention can be applied to the evaluation of local thermal comfort in non-uniform thermal environments such as vehicle air conditioning and local heating / cooling systems. Attached Figure Description

[0012] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0013] Figure 1 This is a flowchart of the method in Example 1. Detailed Implementation

[0014] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0015] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the invention. The terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0016] In this embodiment of the invention, "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of this invention, "multiple" refers to two or more.

[0017] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0018] All data acquisition in this embodiment is carried out in accordance with laws and regulations and with user consent, and the data is used legally.

[0019] Example 1 like Figure 1 As shown, this embodiment provides a method for evaluating thermal comfort based on a local standard effective temperature, including: S1: Obtain local physiological parameters of the target body part in the actual environment; S2: Define the standard environment; S3: Based on the local physiological parameters of the target body part in the actual environment and the principle of heat loss conservation, an energy balance equation is constructed. The energy balance equation is used to describe the relationship between the total heat dissipation of the target body part in the actual environment and the theoretical total heat dissipation in the defined standard environment. S4: Solve the energy balance equation to obtain the local standard effective temperature of the part; wherein, the local standard effective temperature refers to the air temperature of the standard environment when the total heat exchange between a local part of the human body and the standard environment is equal to the total heat exchange of the part in the actual environment.

[0020] The specific steps for S1 to obtain local physiological parameters of the target body part are as follows: In this embodiment, the JOS-3 human thermoregulation model, known in the art, is used to obtain the skin temperature of the target area under actual environmental conditions. Skin moisture and total heat loss per unit area Total heat loss includes the sum of sensible and latent heat losses. Specifically, local physiological parameters include: skin temperature under actual environmental conditions. Skin moisture Total heat dissipation per unit area of ​​skin Total heat dissipation per unit area of ​​skin This represents the total heat dissipation of the target body part in the actual environment.

[0021] It is understandable that the aforementioned local physiological parameters can also be obtained through simulation using other thermophysiological models, or directly measured through warm-body dummy experiments or human experiments. Any method capable of obtaining the skin temperature of the target area under actual environmental conditions... Skin moisture Total heat dissipation per unit area of ​​skin All methods described herein do not depart from the basic concept of this invention.

[0022] The specific steps for defining a standard environment using S2 are as follows: A unified and ideal standard environment is defined as the calculation benchmark for equivalent temperature. In this embodiment, the standard environment parameters are set as follows: relative humidity 50%, wind speed below 0.1 m / s, air temperature equal to mean radiation temperature isothermal environment, metabolic rate is 1.0 met (58.2 W / m²), and clothing thermal resistance is 0.6 clo (0.093 m²·K / W). Under this standard environment, if the total heat exchange between a local part of the human body and the standard environment is equal to the actual heat exchange, then the air temperature of the standard environment is the standard effective temperature of that local part.

[0023] The specific steps for S3 are as follows: An energy balance equation is constructed based on the local physiological parameters of the target body part in the actual environment and the principle of heat loss conservation, specifically:

[0024] in, This represents the total heat dissipation per unit area of ​​the skin, expressed in units of... ; For clothing area factor; For inherent clothing thermal efficiency; The sensible heat transfer coefficient under standard conditions, in units of... ; Skin temperature, in °C; Permeation efficiency is used to measure the amount of water vapor that evaporates from the skin surface into the surrounding air through clothing. This is the Lewis coefficient, with units of ℃ / kPa; The evaporative heat transfer coefficient under standard conditions is expressed in units of 1000 ppm. ; For skin moisture; and They are and The saturated water vapor pressure at this temperature is expressed in kPa.

[0025] In the above energy balance equation, further calculations are needed. Clothing area factor Evaporation heat transfer coefficient under standard conditions Inherent clothing thermal efficiency, Sensible heat transfer coefficient under standard conditions The calculation method for penetration efficiency is as follows.

[0026] Sensible heat transfer coefficient under S3.1 standard environment The calculation process is as follows: S3.1.1 Calculate the thermal resistance of clothing under standard conditions and Both represent the thermal resistance of clothing under standard conditions. The thermal resistance of clothing under standard conditions is expressed in Clo. For the same variable expressed in SI units, with units of m²·K / W, the two satisfy the conversion relationship: .

[0027] Thermal resistance of clothing under standard conditions The specific calculation process is as follows:

[0028] METFACTOR is a factor that converts the actual metabolic rate into the standard metabolic rate. , These are the human body's energy metabolism rate and the mechanical work performed by the human body, respectively. .

[0029] S3.1.2 Calculate the sensible heat transfer coefficient under standard conditions :

[0030] in, The convective heat transfer coefficient under standard conditions is calculated as follows: ,and

[0031] The radiative heat transfer coefficient under standard conditions is calculated as follows:

[0032] In the formula, It is a mathematical function used to calculate exponentiation; The Stefan-Boltzmann coefficient; The temperature of the outer surface of the garment is expressed in °C.

[0033] S3.2 Clothing Area Factor The calculation process is as follows: S3.2.1 Calculate the area factor of clothing under standard conditions :

[0034] in, The area coefficient for clothing is set to 0.25. S3.2.2 Calculate the clothing area factor :

[0035] S3.3 The formula for calculating the inherent thermal efficiency of clothing is:

[0036] S3.4 The formula for calculating the evaporative heat transfer coefficient under standard conditions is:

[0037] In the above formula, The air layer moisture resistance under standard conditions is expressed in m²·kPa / W, and the specific calculation formula is as follows: ;in, The Lewis coefficient is taken as 16.5℃ / kPa in this embodiment; The moisture resistance of clothing under standard conditions is expressed in m²·kPa / W, and its calculation formula is as follows:

[0038] in, The moisture permeability index of clothing is calculated using the following formula: The initial value is... =0.45, after correction .

[0039] S3.5 The formula for calculating penetration efficiency is:

[0040] The specific steps of S4 are as follows: In the energy balance equation constructed in step S3, the unknown is... The temperature difference that appears in the sensible heat term In the middle, it is also through saturated vapor pressure The latent heat term is implicit and cannot be solved directly. Therefore, the equation needs to be transformed into a nonlinear equation. The form is:

[0041] in, This represents the total heat loss in the actual environment. And a numerical method is used to solve iteratively.

[0042] In this embodiment, the Newton-Raphson iteration method is used to solve the nonlinear equation for the local standard effective temperature to obtain the local standard effective temperature at that location. The local standard effective temperature refers to the air temperature of a specific part of the human body within a set standard environment, where the total heat exchange between that part and the standard environment equals the total heat exchange between that part and the actual environment. Therefore, the local standard effective temperature accurately reflects the state of total heat exchange between a local area of ​​the human body and its microenvironment.

[0043] Simulation test First, a benchmark experiment was conducted.

[0044] In the benchmark verification, if the actual environmental parameters are completely consistent with the standard reference environment, the calculated local standard effective temperature should be close to the original air temperature, proving the self-consistency of the algorithm. The results are shown in Table 1. The verification results show that, The error is within ±0.5℃. In the logic verification of extreme hot and cold scenarios, when the JOS-3 measures a sharp increase in local heat dissipation, the calculated local standard effective temperature will be significantly lower than the skin temperature. Conversely, when the local heat dissipation is negative due to local heating, the local standard effective temperature will be higher than the skin temperature. This fully demonstrates that the calculation method can objectively and realistically reflect the thermal stress state of the human body in a local area.

[0045] Table 1 Algorithm self-consistency verification table Air temperature / °C Mean radiant temperature / °C Back standard effective temperature / ℃ 20 20 19.71 23 23 22.87 25 25 24.96 28 28 28.03 30 30 30.44 32 32 32.77 34 34 35.00 36 36 37.11 To further verify the effectiveness of this method, a warm-body dummy was used for physical simulation verification.

[0046] Experimental conditions: A heating device was installed on the back of the mannequin to simulate localized heating, while other areas were not heated to simulate heating of only the back. The mannequin was in a standing posture, and two states were set up depending on whether it was dressed: naked and dressed (clothing thermal resistance 0.3clo).

[0047] The environmental conditions were: air temperature set at 21.22~21.36℃; relative humidity below 50%; and no significant wind speed.

[0048] Experimental steps: Use the JOS-3 model to simulate and obtain the physiological parameters of the back. Substitute the above parameters into this method to calculate the standard effective temperature of the back.

[0049] Experimental results: In the naked state, the standard effective temperature of the back is 10.59℃; in the dressed state with a thermal resistance of 0.3clo, the standard effective temperature of the back is 2.95℃, as shown in Table 2.

[0050] Table 2. Validation Results of the Warm Body Dummy Air temperature / °C Back standard effective temperature / ℃ nude test 21.22 10.59 Clothing test 0.3clo 21.36 2.95 Results Analysis: When naked, the back is directly exposed to the environment, resulting in stronger heat dissipation and a lower equivalent temperature; when dressed, clothing provides insulation, and the equivalent temperature should be slightly higher (but still lower than the ambient temperature, as the increased heat dissipation due to back heating). The verification results are consistent with theoretical expectations based on heat loss, proving that this method can effectively reflect changes in local thermal state.

[0051] Example 2 A thermal comfort evaluation system based on local standard effective temperature, characterized in that it includes: The local physiological parameter acquisition module is used to acquire the local physiological parameters of the target body part in the actual environment. The standard environment definition module is used to define the standard environment; An energy balance equation construction module is used to construct an energy balance equation based on the local physiological parameters and the principle of heat loss conservation. The energy balance equation is used to describe the relationship between the total heat dissipation of the target body part in the actual environment and the theoretical total heat dissipation in the standard environment. The local standard effective temperature calculation module is used to solve the energy balance equation to obtain the local standard effective temperature of the part. The local standard effective temperature refers to the air temperature of the standard environment when the total heat exchange between a local part of the human body and the standard environment is equal to the total heat exchange of the part in the actual environment.

[0052] Example 3 This embodiment also provides an electronic device, including: one or more processors, one or more memories, and one or more computer programs; wherein, the processor is connected to the memory, and the one or more computer programs are stored in the memory. When the electronic device is running, the processor executes the one or more computer programs stored in the memory to cause the electronic device to perform the method described in Embodiment 1.

[0053] It should be understood that in this embodiment, the processor can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc.

[0054] Memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of memory may also include non-volatile random access memory. For example, memory may also store information about the device type.

[0055] In the implementation process, each step of the above method can be completed by the integrated logic circuits in the processor hardware or by software instructions.

[0056] The method in Embodiment 1 can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor. The software modules can reside in readily available storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory; the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, a detailed description is not provided here.

[0057] Those skilled in the art will recognize that the units and algorithm steps described in connection with the various examples of this embodiment can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention.

[0058] Example 4 This embodiment also provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, complete the method described in Embodiment 1.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for evaluating thermal comfort based on local standard effective temperature, characterized in that, include: Obtain local physiological parameters of the target body part in the actual environment; Define a standard environment; An energy balance equation is constructed based on the local physiological parameters of the target body part in the actual environment and the principle of heat loss conservation. The energy balance equation is used to describe the relationship between the total heat dissipation of the target body part in the actual environment and the theoretical total heat dissipation in the defined standard environment. Solving the energy balance equation yields the local standard effective temperature of the affected area. The local standard effective temperature refers to the air temperature of the standard environment when the total heat exchange between a local part of the human body and the standard environment is equal to the total heat exchange of that part in the actual environment.

2. The thermal comfort evaluation method based on local standard effective temperature as described in claim 1, characterized in that, The standard environment refers to an isothermal environment with a relative humidity of 50%, a wind speed of less than 0.1 m / s, and an air temperature equal to the mean radiant temperature, a metabolic rate of 1.0 met (58.2 W / m²), and a clothing thermal resistance of 0.6 clo (0.093 m²·K / W).

3. The thermal comfort evaluation method based on local standard effective temperature as described in claim 1, characterized in that, Specifically, the JOS-3 human thermoregulation model was used to obtain the local physiological parameters of the target body parts in the actual environment.

4. The thermal comfort evaluation method based on local standard effective temperature as described in claim 1, characterized in that, The local physiological parameters include: skin temperature, skin moisture, and total heat dissipation per unit area of ​​skin under actual environmental conditions.

5. The thermal comfort evaluation method based on local standard effective temperature as described in claim 1, characterized in that, The energy balance equation is constructed based on the local physiological parameters of the target body part in the actual environment and the principle of heat loss conservation. The specific formula is as follows: in, This represents the total heat dissipation per unit area of ​​the skin, expressed in units of... ; For clothing area factor; For inherent clothing thermal efficiency; This is the sensible heat transfer coefficient, in units of... ; Skin temperature, in °C; Permeation efficiency is used to measure the amount of water vapor that evaporates from the skin surface into the surrounding air through clothing. This is the Lewis coefficient, with units of ℃ / kPa; The evaporative heat transfer coefficient under standard conditions is expressed in units of 1000 ppm. ; For skin moisture; and They are and The saturated water vapor pressure at this temperature is expressed in kPa.

6. The thermal comfort evaluation method based on local standard effective temperature as described in claim 1, characterized in that, The energy balance equation is solved to obtain the local standard effective temperature of that location, specifically as follows: The energy balance equation is transformed into a nonlinear equation, and the Newton-Raphson iteration method is used to solve the nonlinear equation to obtain the local standard effective temperature value of the part.

7. A thermal comfort evaluation system based on local standard effective temperature, characterized in that, include: The local physiological parameter acquisition module is used to acquire the local physiological parameters of the target body part in the actual environment. The standard environment definition module is used to define the standard environment; An energy balance equation construction module is used to construct an energy balance equation based on the local physiological parameters and the principle of heat loss conservation. The energy balance equation is used to describe the relationship between the total heat dissipation of the target body part in the actual environment and the theoretical total heat dissipation in the standard environment. The local standard effective temperature calculation module is used to solve the energy balance equation to obtain the local standard effective temperature of the part. The local standard effective temperature refers to the air temperature of the standard environment when the total heat exchange between a local part of the human body and the standard environment is equal to the total heat exchange of the part in the actual environment.

8. The thermal comfort evaluation system based on local standard effective temperature as described in claim 7, characterized in that, The standard environment refers to an isothermal environment with a relative humidity of 50%, a wind speed of less than 0.1 m / s, and an air temperature equal to the mean radiant temperature, a metabolic rate of 1.0 met (58.2 W / m²), and a clothing thermal resistance of 0.6 clo (0.093 m²·K / W).

9. An electronic device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the steps of the thermal comfort evaluation method based on a local standard effective temperature as described in any one of claims 1-7.

10. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium is used to store computer instructions, which, when executed by a processor, implement the steps in the thermal comfort evaluation method based on a local standard effective temperature as described in any one of claims 1-7.

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