Effective surface area
14.00 ft² · 1.30 m²
wall-mounted: [2·24·24 + 2·12·24 + 1·24·12] / 144 = 14.00 ft².
Method: sealed-enclosure heat transfer coefficients per nVent Hoffman / Rittal enclosure thermal guides
Calculator 05 / Thermal management
Enclosure heat
Size passive and active cooling, predict internal temperature, and select a heater from panel dimensions, material, and device heat loss.
Enclosure and heat inputs
Temperature units
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VoltForgeEnclosure Heat Report
Project / job name: —
Date: —
Site: voltforgelab.com
Inputs
| Width | 24 in |
| Height | 24 in |
| Depth | 12 in |
| Material / mounting | painted steel / wall-mounted |
| Device heat loss | 50 W |
| Temperature inputs | Ambient 77°F; max 104°F; min 50°F; min ambient 14°F |
Results
Predicted temperature
ΔT 9.4°F · internal 86.4°F
ΔT = Q/(k·A) = 50/(0.38 W/(°F·ft²)·14.00 ft²) = 9.4°F = 5.2°C; ambient 77°F.
Hoffman k = 0.38 W/(°F·ft²); derived 0.2111 W/(°C·ft²) · Hoffman-only thermal method
Cooling verdict
ACTIVE COOLING REQUIRED
Required 5.7 W · 19.3 BTU/h · fan 0.7 CFM at allowed ΔT 15°C (27°F).
Cooling: passive capacity k·A·ΔT; fan 3.16·W/ΔT(°F); BTU/h = W × 3.412
Heater
59.1 W required · 100 W standard
Heater = k·A·(Tₘᵢₙ−Tₐmb,min) = [object Object]·14.00·(50°F − 14°F) = 59.1 W. Standard sizes: 50, 100, 150, 200, 300, 400, 500 W.
Heating: sealed-enclosure method · round up to standard heater size
Engineering disclaimer: This design aid is not a substitute for engineering judgment. Confirm final design with a licensed professional engineer and the authority having jurisdiction.
Effective surface area
14.00 ft² · 1.30 m²
wall-mounted: [2·24·24 + 2·12·24 + 1·24·12] / 144 = 14.00 ft².
Method: sealed-enclosure heat transfer coefficients per nVent Hoffman / Rittal enclosure thermal guides
Predicted temperature
ΔT 9.4°F · internal 86.4°F
ΔT = Q/(k·A) = 50/(0.38 W/(°F·ft²)·14.00 ft²) = 9.4°F = 5.2°C; ambient 77°F.
Hoffman k = 0.38 W/(°F·ft²); derived 0.2111 W/(°C·ft²) · Hoffman-only thermal method
Cooling verdict
ACTIVE COOLING REQUIRED
Required 5.7 W · 19.3 BTU/h · fan 0.7 CFM at allowed ΔT 15°C (27°F).
Cooling: passive capacity k·A·ΔT; fan 3.16·W/ΔT(°F); BTU/h = W × 3.412
Heater
59.1 W required · 100 W standard
Heater = k·A·(Tₘᵢₙ−Tₐmb,min) = [object Object]·14.00·(50°F − 14°F) = 59.1 W. Standard sizes: 50, 100, 150, 200, 300, 400, 500 W.
Heating: sealed-enclosure method · round up to standard heater size
How this was calculated
- Calculate effective enclosure surface area from width, height, depth, and mounting.
- Use the Hoffman material coefficient k = 0.38 W/(°F·ft²) (derived 0.2111 W/(°C·ft²)) to calculate temperature rise from device heat loss.
- Compare heat loss with passive capacity at the desired maximum internal temperature; size active cooling if needed.
- Calculate heater wattage to reach the minimum internal temperature and round up to a standard size.
Sealed-enclosure heat transfer coefficients per nVent Hoffman / Rittal enclosure thermal guides. Coefficients are standard published values — confirm against the enclosure manufacturer's literature for final design.
Engineering disclaimer: This design aid is not a substitute for engineering judgment. Confirm final thermal performance with the enclosure and cooling-device manufacturer, installation conditions, and the authority having jurisdiction.