Altitude Correction Calculator for Air Cooling

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A calculator provides an initial engineering target, but the final cooling solution also depends on geometry, available space, heat source distribution, airflow or coolant conditions, mounting and manufacturing requirements.

Share your drawing and operating conditions with Ecotherm. Our thermal team can provide a free drawing feasibility review and recommend a custom cooling solution for your application.

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High-altitude forced-air design check

Altitude Correction Calculator

Translate a sea-level forced-air cooling design to the project site. See actual pressure and density, the existing fan's same-speed derating, the airflow needed to restore mass flow, and the estimated change in heat-sink thermal resistance.

Project elevation2,500 m

1 · Site conditionAltitude + inlet temperature

2 · Reference designAirflow + pressure + Rθ

3 · Project decisionKeep, boost or resize

Project site

Use the maximum expected cooling-air inlet temperature, not the average outdoor temperature.

Installation altitude

Actual inlet-air temperature

°C

Site pressureKnown local pressure improves density accuracy when weather or pressurization differs from the standard atmosphere.

Sea-level reference design

Fan/thermal reference-air temperature

°C

Forced-air heat sink type

Reference design airflow

System static pressure at reference airflow

Measured/rated heat-sink RθSA

°C/W

Heat load into heat sink

Maximum allowed heat-sink base temperature

°C

Reference fan input power

Used only for the fan-law power trend.

Heat-transfer correction assumptions

Air-side share of RθSA

The remaining share is treated as density-insensitive conduction/spreading.

Density correction exponentForced turbulent channels commonly use a stronger correction than open or mixed flow.

Site air condition

2,500 m · 40°C inlet · standard-atmosphere pressure

Absolute pressure—ISA estimate

Actual air density—At entered inlet temperature

Density ratio—Versus reference condition

ISA temperature—Reference atmosphere only

Available air mass per unit volume—

—

Option AKeep the original fan speed

Volumetric airflow—

Mass-flow capacity—

Fan/system pressure scale—

Corrected heat-sink RθSA—

Estimated base temperature—

Option BRestore reference mass flow

Required volumetric airflow—

Airflow increase—

Approx. fan speed factor—

System pressure target—

Fan-law power trend—

—

Sea-level reference vs. same-speed site estimate

Air density

—

Mass-flow capacity

—

Static pressure

—

Cooling conductance

—

How to use the result: standard-atmosphere pressure is a design estimate, not a weather forecast. The same-speed volume-flow assumption works when the same fan and system geometry are used because both fan pressure and system resistance scale with density. Always confirm the manufacturer's complete fan curve, speed limit, motor power and high-temperature rating.

For high-altitude forced-air design review, share the installation elevation, maximum inlet temperature, heat load, heat-sink drawing, enclosure flow path and full fan curve. Ecotherm can adjust the custom heat-sink geometry and airflow requirement without treating this estimate as a fan or system performance guarantee.