Stirling engine
Instead of generating electricity to turn a motor, sunlight can be concentrated on the heat exchanger of a Stirling engine and used to drive a pump mechanically. This dispenses with the cost of solar panels and electric equipment. In some cases, the Stirling engine may be suitable for local fabrication, eliminating the difficulty of importing equipment. One form of Stirling engine is the fluidyne engine, which operates directly on the pumped fluid as a piston. Fluidyne solar pumps have been studied since 1987. At least one manufacturer has conducted tests with a Stirling solar-powered pump.