Electrical Heating Mass

Overview

Engineering reference data for Electrical Heating Mass 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

Symbol	Description	Unit
$\sigma$	Stress	Pa
$\varepsilon$	Strain	—
$E$	Young's modulus	Pa
$\alpha$	Thermal expansion coefficient	1/°C
$\Delta T$	Temperature change	°C

Example Calculation

The temperature change can be calculated by rearranging the energy balance formula:

$dT = \frac{U \cdot I \cdot t \cdot \mu}{c \cdot m}$

12 Volt Car Water Heater Example:

• Voltage (U): 12 V
• Current (I): 10 A
• Time (t): 5 minutes = 300 seconds
• Efficiency (μ): 1 (100%)
• Specific heat of water (c): 4200 J/kg·°C
• Mass of water (m): 0.4 kg

$dT = \frac{(12 \text{ V}) \cdot (10 \text{ A}) \cdot (300 \text{ s}) \cdot (1)}{(4200 \text{ J/kg·°C}) \cdot (0.4 \text{ kg})} = 21.4 \text{ °C}$

Important Considerations:

• This calculation assumes 100% efficiency (μ = 1).
• In reality, the mass of the heater itself absorbs some heat.
• Heat loss to the environment during heating is neglected.
• The specific heat value (c) varies by substance (e.g., water is ~4186 J/kg·°C, iron is ~449 J/kg·°C).

References

• Original Source