Waste Heat Engine

Waste Heat Engine

A Waste Heat Engine, as the name implies, is an engine that runs on the waste heat from some other source. This heat source could be a heating system, power system or geothermal heat from the earth itself. A prime example fo a waste heat engine is the Stirling Engine.

The Stirling Engine is an external combustion engine, this means that instead of there being an explosion inside the cylinders to create the power (like in most engines), the power can be outside the engine and can take any form at all.

Here is a video of  solar powered stirling engine, running on a temperature differential of only a couple of degrees -

This little Waste Heat Engine/Stirling Engine will sit here running on sunlight for hours, they can also run off a beside lamp.
Other engines can produce usable power, they work on similar principles to the stirling engine shown above, but have two cylinders instead of one and operate at higher temperatures,and use a parabolic dish to focus sunlight to a single point, here is an example -