SORCE: A design tool for solar organic Rankine cycle systems in distributed generation applications

Recent interest in small-scale solar thermal combined heat and power (CHP) power systems has coincided with demand growth for distributed electricity supplies in areas poorly served by centralized power stations. One potential technical approach to meeting this demand is the parabolic trough solar thermal collector coupled with an organic Rankine cycle (ORC) heat engine. Much existing research touches on aspects of the underlying physics and mechanics of this technology, but a holistic treatment including economic evaluation is lacking. Design and analysis tools are needed to specify the solar collector and power block configurations for meeting performance and financial targets for a range of applications in disparate environments. In this paper we present the Solar Organic Rankine Cycle Economic (SORCE) model combining semi-empirical multi-physics computation modules for solar resource and site environmental parameter characterization along with optical, thermal and electromechanical performance prediction of trough collectors and ORC systems with technical specifications and costs of standard system equipment. The model is tested with data from experimental solar ORC systems at MIT and deployed in Lesotho, southern Africa (29°12'48.44"S, 27°51'37.36"E). SORCE is available for download1 as an executable program derived from Engineering Equation Solver (EES) that enables site-specific evaluation of a solar ORC system for performance and cost comparison with alternatives (e.g. wind, solar PV, diesel, etc.).