🌡️ Radiative Cooling/Heating Calculator

Advanced Computational Tool for Thermal Radiation Analysis

A sophisticated software package for calculating radiative cooling and heating power, designed for researchers and engineers in thermal management, building energy efficiency, and advanced material science.

📖 Overview

The Radiative Cooling/Heating Calculator provides accurate calculations of radiative heat transfer by incorporating:

🌅 Solar radiation (AM1.5G spectrum)
🌍 Atmospheric transparency windows (8-13 μm)
🔬 Material optical properties (spectral emissivity/reflectance)
💨 Convection effects (natural and forced)
📊 Multi-dimensional parametric analysis

✔ How to Download

https://pan.baidu.com/s/1RwgC-En28zfwQtf9DOfw9A?pwd=USTC

[ GitHub Releases](https://github.com/cuity1/Radiation-cooling-and-heating-calculation/releases)

点击链接加入群聊【辐射制冷青椒交流群】

✨ Key Features

Feature	Description
❄️ Radiative Cooling	Calculate cooling power using atmospheric transparency window with precise spectral integration
🔥 Radiative Heating	Compute heating power considering solar absorption and atmospheric downward radiation
🗺️ Energy Mapping	Generate energy efficiency maps for geographical and climate analysis
💨 Convection Analysis	Wind speed effects on cooling efficiency with Reynolds and Nusselt correlations
📊 Data Visualization	Interactive plots, contour maps, and 3D parametric surfaces
🔧 Material Properties	Customizable spectral emissivity and reflectance for various materials
🌐 Multi-language	Interface in Chinese and English with dynamic switching
⚙️ Configuration Editor	Built-in editor for modifying calculation parameters

🔬 Physical Principles

1. Planck's Law of Blackbody Radiation

The spectral radiance of a blackbody at temperature $T$ is given by:

$$ I_{BB}(\lambda, T) = \frac{2hc^2}{\lambda^5} \frac{1}{e^{\frac{hc}{\lambda k_B T}} - 1} $$

Where:

$h = 6.626 \times 10^{-34}$ J·s (Planck's constant)
$c = 2.998 \times 10^8$ m/s (speed of light)
$k_B = 1.381 \times 10^{-23}$ J/K (Boltzmann constant)
$\lambda$ = wavelength (m)
$T$ = temperature (K)

2. Net Radiative Cooling Power

The net cooling power of a radiative cooler:

$$ P_{cool}(T) = P_{rad}(T) - P_{atm}(T_{amb}) - P_{solar} - P_{conv} $$

a) Radiative Power (Upward)

$$ P_{rad}(T) = \int_0^{2\pi} d\phi \int_0^{\pi/2} \cos\theta \sin\theta , d\theta \int_{\lambda_1}^{\lambda_2} \varepsilon(\lambda, \theta) I_{BB}(\lambda, T) , d\lambda $$

b) Atmospheric Radiation (Downward)

$$ P_{atm}(T_{amb}) = \int_0^{2\pi} d\phi \int_0^{\pi/2} \cos\theta \sin\theta , d\theta \int_{\lambda_1}^{\lambda_2} \varepsilon(\lambda, \theta) \varepsilon_{atm}(\lambda, \theta) I_{BB}(\lambda, T_{amb}) , d\lambda $$

Atmospheric emissivity from Beer-Lambert law:

$$ \varepsilon_{atm}(\lambda, \theta) = 1 - \tau(\lambda)^{\sec\theta} $$

c) Solar Absorption

$$ P_{solar} = \alpha_s \cdot I_{solar} $$

Solar absorptance (weighted over AM1.5G spectrum):

$$ \alpha_s = 1 - R_{sol} = 1 - \frac{\int_{0.3}^{2.5} R(\lambda) I_{AM1.5}(\lambda) d\lambda}{\int_{0.3}^{2.5} I_{AM1.5}(\lambda) d\lambda} $$

d) Convective Heat Transfer

$$ P_{conv} = h_c \cdot (T - T_{amb}) $$

3. Convection Coefficient Calculation

Natural Convection

Rayleigh number:

$$ Ra = \frac{g\beta \Delta T L^3}{\nu \alpha} = Gr \cdot Pr $$

Nusselt number:

$$ Nu_{nat} = \begin{cases} 0.54 \cdot Ra^{1/4} & Ra < 10^7 \text{ (laminar)} \\ 0.15 \cdot Ra^{1/3} & Ra > 10^7 \text{ (turbulent)} \end{cases} $$

Forced Convection

Reynolds number:

$$ Re = \frac{v L}{\nu} $$

Nusselt number:

$$ Nu_{forced} = \begin{cases} 0.664 \cdot Re^{1/2} \cdot Pr^{1/3} & Re < 5 \times 10^5 \text{ (laminar)} \\ 0.037 \cdot Re^{4/5} \cdot Pr^{1/3} & Re > 5 \times 10^5 \text{ (turbulent)} \end{cases} $$

Combined Convection (Churchill-Usagi Method)

$$ h_c = (h_{nat}^n + h_{forced}^n)^{1/n}, \quad n = 3 $$

4. Temperature-Weighted Average Emissivity

$$ \bar{\varepsilon}(T) = \frac{\int_{\lambda_1}^{\lambda_2} \varepsilon(\lambda) I_{BB}(\lambda, T) d\lambda}{\int_{\lambda_1}^{\lambda_2} I_{BB}(\lambda, T) d\lambda} $$

🖥️ Computational Features

Numerical Integration

Method	Application	Accuracy
Trapezoidal Rule	Spectral integration	$O(\Delta\lambda^2)$
Brent's Method	Root finding for equilibrium	Machine precision
Linear Interpolation	Spectral resampling	$O(\Delta\lambda)$
Minimize Scalar	Optimization for solutions	Configurable tolerance

Integration Parameters

Angular Integration: 100+ discrete points from 0° to 90°
Wavelength Integration: User-defined spectral ranges with automatic interpolation
Convergence Criteria: Iterative solving with $\Delta T < 0.01$ K

Material Property Processing

✅ Automatic wavelength unit conversion (nm ↔ μm)
✅ Multi-encoding file support (UTF-8, GBK, GB2312)
✅ Spectral data validation and error handling
✅ Interpolation using scipy.interpolate.interp1d

⚙️ Installation

System Requirements

Python >= 3.7
PyQt5 >= 5.15
numpy >= 1.19
scipy >= 1.5
pandas >= 1.1
matplotlib >= 3.3
openpyxl >= 3.0

Installation Steps

# Clone the repository
git clone https://github.com/yourusername/radiation-calculator.git
cd radiation-calculator

# Create virtual environment (recommended)
python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

# Install dependencies
pip install -r requirements.txt

# Run the application
python main.py

Requirements File

Create requirements.txt:

PyQt5>=5.15.0
numpy>=1.19.0
scipy>=1.5.0
pandas>=1.1.0
matplotlib>=3.3.0
openpyxl>=3.0.0
configparser
pillow

📁 Required Data Files

All data files should be placed in the default/ directory:

File	Description	Format	Required Columns
`config.ini`	Configuration parameters	INI	Multiple sections
`AM1.5.dll`	Standard solar spectrum (AM1.5G)	Excel	λ (μm), I (W/m²/μm)
`wavelength.csv`	Wavelength grid	CSV	λ (μm)
`reflectance.txt`	Material reflectance (0.3-2.5 μm)	TXT	λ (μm), R
`emissivity.txt`	Material emissivity (8-13 μm)	TXT	λ (μm), ε
`1.dll`	Atmospheric transmittance (clear)	Excel	λ (μm), τ
`2.dll`	Atmospheric transmittance (cloudy)	Excel	λ (μm), τ

Example Data Format

reflectance.txt:

0.3    0.95
0.4    0.94
0.5    0.93
...
2.5    0.90

emissivity.txt:

8.0    0.98
8.5    0.97
9.0    0.96
...
13.0   0.95

⚠️ Important: Data files must contain only numerical values (no headers, no text). Use tab or space as delimiter.

🎯 Usage Guide

1. Basic Cooling Power Calculation

# GUI Workflow:
1. Launch application: python main.py
2. Select reflectance file (visible to near-IR)
3. Select emissivity file (mid-IR atmospheric window)
4. Choose atmospheric conditions (1.dll or 2.dll)
5. Click "Radiation Cooling Power"
6. View results and export data

Expected Output:

Cooling Power: XXX.XX W/m² at ambient temperature
Solar Absorptance: α_s
Average Emissivity: ε_avg
Interactive plot: Cooling Power vs. ΔT

2. Energy Map Generation

# For geographical energy modeling:
1. Prepare material property files
2. Click "Energy Map Calculation"
3. Obtain:
   - Material weighted emissivity (ε_8-13μm)
   - Solar spectral reflectance (R_0.3-2.5μm)
   - Visible spectral reflectance (R_0.4-0.7μm)
4. Use parameters in regional climate models

3. Wind Speed Analysis

# Generate 2D parametric maps:
1. Load all required material files
2. Select "Wind Speed & Cooling Efficiency"
3. Input solar irradiance (e.g., 1000 W/m²)
4. View contour maps:
   - X-axis: Wind speed (0-5 m/s)
   - Y-axis: Atmospheric emissivity (0-1)
   - Color: Temperature difference or cooling power

4. Atmospheric Emissivity-Solar Irradiance Cloud

# Comprehensive parametric study:
1. Click "Atmospheric Emissivity-Solar Irradiance Cloud"
2. Software generates 2D map:
   - X-axis: Atmospheric emissivity (0-1)
   - Y-axis: Solar irradiance (0-1000 W/m²)
   - Color: Net cooling power at ΔT=0
3. Export data to Excel with two sheets

📊 Output Parameters

Calculated Values

Parameter	Unit	Description
P_cool	W/m²	Net radiative cooling power at T_film = T_amb
P_heat	W/m²	Net radiative heating power
α_solar	-	Solar-weighted absorptance (0.3-2.5 μm)
ε_avg	-	Temperature-weighted emissivity (8-13 μm)
R_sol	-	Solar-weighted reflectance
R_vis	-	Visible-weighted reflectance (0.4-0.7 μm)
h_c	W/m²·K	Convection coefficient

Visualization Outputs

📈 Line plots: Cooling/heating power vs. temperature difference
🗺️ Contour maps: 2D parametric surfaces
📊 Excel exports: Tabulated data for further analysis
🎨 Customizable plots: Publication-quality figures

🔧 Advanced Features

Configuration Editor

Edit calculation parameters through the GUI:

[PHYSICAL_CONSTANTS]
H = 6.62607015e-34      # Planck's constant (J·s)
C = 2.99792458e8        # Speed of light (m/s)
KB = 1.380649e-23       # Boltzmann constant (J/K)

[CALCULATIONS]
T_a1 = 25.0             # Ambient temperature (°C)
T_filmmin = -100.0      # Min film temperature (°C)
T_filmmax = 100.0       # Max film temperature (°C)
S_solar = 1000          # Solar irradiance (W/m²)
HC_VALUES = 5, 10, 15   # Convection coefficients (W/m²·K)
WAVELENGTH_RANGE = 0.3, 2.5    # Solar spectrum (μm)
VISIABLE_RANGE = 0.4, 0.7      # Visible spectrum (μm)

File Converter Tool

Convert Excel files to TXT format:

Automatically extracts first two columns
Handles multiple encodings
Validates data structure

Multi-language Interface

Switch between Chinese and English:

Real-time language switching
All dialogs and messages translated
Formulas remain in standard notation

📈 Validation & Accuracy

Key Considerations

✅ Spectral Resolution: Higher resolution improves accuracy (recommend Δλ < 0.1 μm)

✅ Angular Integration: 100+ points ensure convergence (tested error < 0.5%)

✅ Temperature Range: Validated from -100°C to +100°C

✅ Wavelength Coverage: Critical ranges: Solar (0.3-2.5 μm), IR (8-13 μm)

Assumptions & Limitations

⚠️ Diffuse Surface: Assumes Lambertian emission/reflection

⚠️ Steady State: Transient effects not included

⚠️ 1D Heat Transfer: Edge effects neglected

⚠️ Standard Atmosphere: Uses MODTRAN-based profiles

🛠️ Troubleshooting

Common Issues

Problem: "Cannot read file with any encoding"

Solution: Ensure file contains only numbers, no headers or text
Convert file to UTF-8 encoding: iconv -f GBK -t UTF-8 input.txt > output.txt

Problem: "Configuration file missing section"

Solution: Restore default config.ini from repository
Check all required sections: GENERAL, PHYSICAL_CONSTANTS, CALCULATIONS

Problem: Calculation results seem incorrect

Solution: 
1. Verify wavelength units (μm vs nm)
2. Check emissivity/reflectance ranges (0-1, not 0-100)
3. Ensure atmospheric transmittance file matches climate
4. Review temperature settings in config.ini

Problem: GUI doesn't display properly

Solution:
pip install --upgrade PyQt5
# On Linux, may need: sudo apt-get install python3-pyqt5

📚 References

Raman, A. P., et al. "Passive radiative cooling below ambient air temperature under direct sunlight." Nature 515.7528 (2014): 540-544. DOI: 10.1038/nature13883
Zhao, Dongliang, et al. "Radiative sky cooling: Fundamental principles, materials, and applications." Applied Physics Reviews 6.2 (2019): 021306. DOI: 10.1063/1.5087281
Zhai, Yao, et al. "Scalable-manufactured randomized glass-polymer hybrid metamaterial for daytime radiative cooling." Science 355.6329 (2017): 1062-1066.
Incropera, F. P., et al. Fundamentals of Heat and Mass Transfer. 7th ed. Wiley, 2011.
Bergman, T. L., et al. Introduction to Heat Transfer. 6th ed. Wiley, 2011.
Siegel, R., and J. R. Howell. Thermal Radiation Heat Transfer. 5th ed. CRC Press, 2010.
Modest, M. F. Radiative Heat Transfer. 3rd ed. Academic Press, 2013.

🤝 Contributing

Contributions are welcome! Please follow these guidelines:

Fork the repository
Create a feature branch (git checkout -b feature/AmazingFeature)
Commit your changes (git commit -m 'Add some AmazingFeature')
Push to the branch (git push origin feature/AmazingFeature)
Open a Pull Request

Development Guidelines

Follow PEP 8 style guide for Python code
Add docstrings to all functions
Include unit tests for new features
Update documentation for API changes

📬 Contact & Support

Author: CTY
QQ Group: 767753318
WeChat: cuity_
Email: Contact via QQ group
Repository: Gitee

Citation

If you use this software in your research, please cite:

NO INFORMATION

Support the Project

⭐ Star this repository if you find it useful!
🐛 Report bugs via Issues
💡 Suggest features or improvements
📖 Improve documentation

📄 License

This software is provided free for academic and research purposes.

Restrictions:

Commercial use requires explicit permission from the author
Redistribution must include original attribution
Modifications must be clearly documented

Disclaimer: This software is provided "as is" without warranty of any kind. The author is not liable for any damages arising from its use.

🎓 Educational Resources

Tutorial Series

Coming soon: Video tutorials covering:

Basic setup and first calculation
Understanding spectral data requirements
Advanced parametric studies
Interpreting results for real applications

🔄 Version History

Version 3.6 (NEXT Plan)

😋 Add energy-saving map drawing function (this will be charged)

Version 3.6 (Current)

✨ Added atmospheric emissivity-solar irradiance cloud map
✨ Fix the logic of drawing preview

Version 3.5

🌐 Improved multi-language support

Version 3.0

Added wind speed analysis with Churchill-Usagi correlation
Implemented configuration editor
Multi-language interface (Chinese/English)

Version 2.0

Added heating power calculation
Improved spectral integration accuracy
GUI redesign with modern aesthetics

Version 1.0

Initial release with basic cooling power calculation

🌟 Acknowledgments

Special thanks to:

The thermal radiation research community
PyQt5 and Python scientific computing ecosystem
Contributors and users providing feedback
Research groups sharing spectral data

Made with ❤️ for the thermal sciences community

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说明书.pdf		说明书.pdf

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