Solar Radiation Windows

Overview

Engineering reference data for Solar Radiation Windows in heat transfer.

Key Formulas

Fourier's Law

$q = -k \nabla T$

Heat flux proportional to temperature gradient.

Convective Heat Transfer

$Q = hA(T_s - T_\infty)$

Heat transfer between surface and fluid.

Stefan-Boltzmann Law

$q = \varepsilon \sigma T^4$

Radiative heat flux from a surface.

Thermal Resistance

$R_{th} = \frac{L}{kA}$

Resistance to heat conduction.

Variables

Solar Heat Transmission Data by Latitude

The following table compares solar heat transmission through single glass windows at different northern latitudes, considering both vertical and horizontal orientations.

Additional Formula

A fundamental formula for calculating solar heat gain through a window is:

$$Q_{solar} = A \cdot I \cdot SHGC$$

Where:

• $Q_{solar}$ is the solar heat gain (W),
• $A$ is the glazing area (m²),
• $I$ is the incident solar radiation (W/m²),
• $SHGC$ is the Solar Heat Gain Coefficient of the window assembly (dimensionless).

Key Definitions

• Solar Heat Gain Coefficient (SHGC): The fraction of incident solar radiation that is transmitted through a window as heat. A lower SHGC indicates better shading performance.
• Vertical vs. Horizontal Windows: Horizontal windows (skylights) receive more direct solar radiation, especially at lower sun angles, resulting in significantly higher heat transmission compared to vertical windows at the same latitude.

Interactive Charts

References

• Original Source