Small Scale Solar ORC system for distributed power

Abstract

A solar thermal organic Rankine cycle (ORC) can provide affordable energy supplies in remote regions. The advent of low-cost medium temperature parabolic trough collectors and ORC technology taking advantage of mass produced fluid machinery from HVAC industries are enabling developments for the production of small scale autonomous power generation units. Construction and testing of this type of system is discussed, including benchmarking of scrolls expanders (up to 75 % isentropic effieiency) and the field testing of solar collectors (50 % thermal efficiency at 150°C operating temperatures) with a nominal cost of $80 m-2. These results have led to the construction of a full-scale 3kW solar ORC power system designed to support a rural health clinic in Lesotho in southern Africa.