Adrian Bejan | Radial conduction cooling, innovation, from Design in Nature

Jul 11, 2025

In this video, Adrian Bejan reimagines a round slab of electronics, a disc, like a pizza, that generates heat uniformly and is cooled from the center. To prevent the system from overheating, Bejan introduces high-conductivity blades extending radially from the center, dividing the disc into equidistant sectors. Each sector becomes a pizza slice, a fundamental unit of analysis. He shows how the geometry, the material contrast, and the arrangement of slices determine the effectiveness of the design. This model of radial conduction leads to a deeper understanding of architecture, elemental systems, and the way design grows from the shape of the smallest feature.

Bejan divides the disc into triangular sectors, each with a cold center and hot corners, where the temperature difference drives the flow of heat toward the center.
Each sector includes a high-conductivity blade along its centerline, and Bejan defines the key dimensions as the horizontal length (radius) and the vertical span along the perimeter.
He applies the same logic as in earlier designs, with two components of temperature difference, vertical and radial, linked to the amount and quality of high-conductivity material.
The shape of the sector depends on the product of two quantities: the conductivity ratio and the volume fraction of expensive material. This determines both the thermal resistance and the optimal geometry.
Bejan calculates how many slices fit on the disc based on the size of one sector, showing that the elemental system defines the whole. “If you know the slice, you know the pizza.”
He concludes with the idea that radial design enables scaling. By adjusting the properties of the sector, the disc can grow, accommodate more cooling elements, and evolve as a system built from repeatable, efficient parts.

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