Electronics Cooling Calculators and Guides
From power loss to pressure drop: use these calculators to pre-size the cooling of your power electronics. The guides explain materials, designs and limits.
Calculators for thermal design
The calculators follow the order of a real design: power loss first, then the permissible thermal resistance and junction temperature, followed by coolant flow, pressure drop and heat transfer. All results are preliminary estimates. For the final design we work with you using thermal simulation.
- Power loss calculation for MOSFETs and IGBTs Power loss calculation from efficiency or datasheet values: conduction and switching losses of MOSFETs, IGBTs and diodes, with formulas and an example. Open calculator →
- Calculate Thermal Resistance Calculate the required thermal resistance Rth in K/W and size your heat sink: formula, units, typical heat sink values and an assessment of your result. Open calculator →
- Junction Temperature (Tj): Formula and Calculator Calculate Tj in seconds from power dissipation, thermal resistance and ambient temperature. With limits for silicon, SiC and IGBT plus an assessment of your margin. Open calculator →
- Calculate cooling power and flow rate for liquid cooling Calculate the temperature rise of the coolant or the required flow rate for your liquid cooling system. With formula, example, and sizing guide for liquid coolers. Open calculator →
- Calculate Pressure Drop in Liquid Coolers Calculate pressure drop from flow rate, channel geometry and coolant. Free calculator with the formula and the quadratic flow-rate relationship. Open calculator →
- Reynolds number calculator: laminar or turbulent flow in coolant channels Reynolds number calculator for pipes and rectangular coolant channels, with hydraulic diameter, water and glycol viscosity and laminar/turbulent limits. Open calculator →
- Heat transfer coefficient: values, formulas and calculator Heat transfer coefficient explained: typical values for air and water, calculation via the Nusselt number, and a free calculator for h and heat flow rate. Open calculator →
- Heat transfer rate calculator: conduction, convection and radiation Heat transfer rate calculator for conduction, convection and radiation: formulas, units, heat flux and a worked power electronics example with TIM. Open calculator →
Basics and guides
Material properties, selection criteria and designs: background knowledge for choosing between air and liquid cooling.
- Electronics cooling: reliably cool power electronics and semiconductors Electronics cooling for power electronics and semiconductors: choose air or liquid cooling correctly, size it, and find the right heat sink from COOLTEC. Read article →
- Air or liquid cooling in power electronics: which solution pays off when? At what power density does switching from air to liquid cooling pay off? Direct comparison for power electronics, server racks and charging infrastructure. Read article →
- When Does an Air Heat Sink No Longer Suffice? Air cooling is cost-effective and low-maintenance, but it has physical limits. Here are the signs that an air heat sink has reached its performance limit and which alternatives to consider. Read article →
- Liquid Cooling at High Power Density: Important Design Criteria Heat transfer coefficient, pressure drop, material: the most important design criteria for liquid coolers at high power density. Read article →
- Cold Plate Design: Which Type Fits Your Application? Monopress, Multipress, Interpress, Structureflow or Embeddedflow: five cold plate designs compared, with selection criteria for your application. Read article →
- Thermal Conductivity of Metals and Cooling Materials: Values, Table, and Formula Thermal conductivity (λ) explained: definition, formula, and a table of values for copper, aluminium, stainless steel, and other materials. Choose the right cooling material. Read article →
- Emissivity Table: Emissivity of Metals, Anodized Aluminium and Coatings Emissivity table for aluminium, anodized aluminium, copper, stainless steel and paint. Definition, radiation formula, worked example and IR camera tips. Read article →
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