Solar-powered Stirling engine

[1] The purpose of this apparatus is to “provide a low-cost, low-technology pump having particular utility in irrigation systems employed in underdeveloped arid regions of the earth…[using] the basic principles of the Stirling heat engine“.

The concentrated solar energy drives a Stirling cycle engine,[2] which operates by letting heat flow from a hot source to a cold sink to do work.

This presented issues because, for the apparatus to have a complete range of motion, lubrication and rotational systems are necessary, and may compromise structural stability.

The apparatus pumped the water into nearby crop fields, providing a “low-cost, low-technology pump having particular utility in irrigation systems employed in underdeveloped arid regions of the earth.” Stirling engines using parabolic solar concentration hold records for the highest efficiency of any thermal conversion system in converting solar energy to electrical power (although the record efficiency of photovoltaic panels is somewhat higher.)

Solar-powered Stirling engines can have a secondary heat source (e.g. Gas), allowing operation during night and when the sky is clouded.