Condensation Glass Surfaces

Overview

Engineering reference data for Condensation Glass Surfaces in material science and properties.

Key Formulas

Stress

$\sigma = \frac{F}{A}$

Force per unit area.

Strain

$\varepsilon = \frac{\Delta L}{L_0}$

Change in length per original length.

Hooke's Law

$\sigma = E \varepsilon$

Stress proportional to strain in elastic region.

Thermal Expansion

$\Delta L = \alpha L_0 \Delta T$

Length change due to temperature.

Variables

Heat Transfer Coefficients (U-values)

The overall heat transfer coefficient (U-value) quantifies heat flow through a window assembly. Higher U-values indicate greater heat transfer and higher condensation risk.

$U_{\text{single}} = 1.13 \, \text{Btu/ft}^2\cdot\text{°F}\cdot\text{hr} = 6 \, \text{W/m}^2\cdot\text{°C}$ $U_{\text{double}} = 0.58 \, \text{Btu/ft}^2\cdot\text{°F}\cdot\text{hr} = 3 \, \text{W/m}^2\cdot\text{°C}$

Condensation Example

For a window with a single pane ($U \approx 6 \, \text{W/m}^2\cdot\text{°C}$) and an indoor air dry-bulb temperature of 18.3°C (65°F) at 50% relative humidity, condensation begins on the interior glass surface when the outdoor temperature drops to:

$T_{\text{outside}} = 6 \, \text{°C} \; (43 \, \text{°F})$

This demonstrates how higher indoor humidity or lower window insulation (higher U-value) leads to condensation at less severe outdoor temperatures.

References

• Original Source