Industrial Enclosure Thermal Solver
Estimate the internal temperature rise of sealed or vented electrical enclosures from heat dissipation, enclosure size, material, and venting, and get the fan CFM you need.
Thermal Results
Professional Insights & Guide
The convection and airflow math that keeps industrial control panels inside their component ratings.
Core Use Case scenario
A sealed steel enclosure loses heat to its surroundings by natural convection and radiation through its walls. The standard sizing rule treats the enclosure as a single thermal resistance: temperature rise equals heat dissipation divided by the product of a heat-transfer coefficient and the total surface area. Steel and painted finishes give roughly 5.5 W/m²·K; aluminum and dark finishes do a little better. When the rise exceeds the component limit, venting or a filter fan must move heat out of the air directly.
Troubleshooting & Edge-Case Failure Points
- Surface area: count all six walls; the floor contributes less, but omitting the back or top changes the result by 20% or more.
- Sun load and adjacent heat sources: an enclosure facing the sun needs an allowance beyond pure internal watts.
- Filter derating: a filter fan delivers only ~60–75% of its free-air CFM through a mat; size for the derated value.
- Recirculation: an exhaust fan placed beside the intake just cycles hot air — the flow path must cross the heat sources.
Detailed Step-by-Step Instructions
- Sum the heat dissipation of every device in the enclosure and enter the watts.
- Enter the enclosure dimensions, material, surface finish, and venting strategy.
- Set the ambient temperature and the maximum allowed internal temperature.
- Press Solve Enclosure Thermal and review the temperature rise, internal temperature, and heat density.
- Read the required and recommended fan CFM, then select a filter fan from a vendor curve that meets the derated value.
Formulas Used
A = 2*(W*H + W*D + H*D) // surface area (m2) dT = P / (h * A) // sealed temperature rise (K) CFM = 1.76 * P / dT_C // required airflow for rise dT (degC) CFM_F = 3.16 * P / dT_F // equivalent in Fahrenheit Recommended = required CFM / 0.7 // 70% filter efficiency allowance Rule: >100 W/m2 → fan ; >300 W/m2 → air conditioner
Professional Insights & Guide
The convection and airflow math that keeps industrial control panels inside their component ratings.
Core Use Case scenario
A sealed steel enclosure loses heat to its surroundings by natural convection and radiation through its walls. The standard sizing rule treats the enclosure as a single thermal resistance: temperature rise equals heat dissipation divided by the product of a heat-transfer coefficient and the total surface area. Steel and painted finishes give roughly 5.5 W/m²·K; aluminum and dark finishes do a little better. When the rise exceeds the component limit, venting or a filter fan must move heat out of the air directly.
Troubleshooting & Edge-Case Failure Points
- Surface area: count all six walls; the floor contributes less, but omitting the back or top changes the result by 20% or more.
- Sun load and adjacent heat sources: an enclosure facing the sun needs an allowance beyond pure internal watts.
- Filter derating: a filter fan delivers only ~60–75% of its free-air CFM through a mat; size for the derated value.
- Recirculation: an exhaust fan placed beside the intake just cycles hot air — the flow path must cross the heat sources.
Detailed Step-by-Step Instructions
- Sum the heat dissipation of every device in the enclosure and enter the watts.
- Enter the enclosure dimensions, material, surface finish, and venting strategy.
- Set the ambient temperature and the maximum allowed internal temperature.
- Press Solve Enclosure Thermal and review the temperature rise, internal temperature, and heat density.
- Read the required and recommended fan CFM, then select a filter fan from a vendor curve that meets the derated value.
Formulas Used
A = 2*(W*H + W*D + H*D) // surface area (m2) dT = P / (h * A) // sealed temperature rise (K) CFM = 1.76 * P / dT_C // required airflow for rise dT (degC) CFM_F = 3.16 * P / dT_F // equivalent in Fahrenheit Recommended = required CFM / 0.7 // 70% filter efficiency allowance Rule: >100 W/m2 → fan ; >300 W/m2 → air conditioner
Informative Guides & Helper Articles
Best Practices for Enclosure Thermal Design
Correct surface area, filter maintenance, intake/exhaust placement, and avoiding recirculation in industrial cabinets.
Read Article →Common Errors in Enclosure Thermal Solver
Wrong surface area, optimistic fan curves, exhausted-against-wall mounting, and filter pressure-drop oversights.
Read Article →Top Optimization Tips for Enclosure Cooling
Dark painted exteriors, internal air guides, heat sinks, source separation, and heat exchangers vs. air conditioners.
Read Article →Future Trends in Enclosure Thermal Design
IIoT thermal monitoring, AI fan control, phase-change materials, liquid cooling, and thermal digital twins.
Read Article →How to Use the Enclosure Thermal Solver
Computes sealed-enclosure temperature rise from internal dissipation, surface area, and construction.
- Enter internal power (W) and enclosure dimensions/material.
- Enter worst-case ambient (derate for sunload).
- Read steady-state internal temperature and margin.
Thermal Ohm Law: dT = P x theta
Heat flows like current: dT = P x R_theta. For sealed boxes, natural convection plus radiation from the outer surface gives combined h of ~6-10 W/m2K - so 20 W in a 0.25 m2 steel box rises about 10C (dT = 20/(8 x 0.25)); a 50C sunloaded ambient means 60C inside, and electrolytic caps lose years of life. Fix ladder: surface area (fins) - aluminum over plastic (200x conductivity) - ventilation - fans - heat pipes. Insulation cuts h dramatically and is the hidden killer.
Enclosure Thermal Solver FAQ
How hot will a sealed enclosure get?
Rise = power x thermal resistance; h of 6-10 W/m2K combined. 20W in a 0.25 m2 box = ~10C rise.
Does material matter?
Aluminum conducts ~200x plastic, spreading heat to more surface. High-emissivity paint also radiates better.
When do I need a fan?
When passive rise plus worst-case ambient exceeds component limits. Filtered fans trade IP rating; heat pipes keep seals intact.