Economic analysis of a solar assisted micro-cogeneration Organic Rankine Cycle system

Combined heat and power production (CHP), also known as cogeneration, is the process of producing both electricity and useful thermal energy at high global efficiency. The designation of micro-cogeneration (or micro-CHP) is applied when the electrical power output is less than 50 kWel. The objective of this work is to evaluate on a cost-benefit basis a micro-cogeneration system, whose electrical energy is produced through a “Scroll”-type micro-turbine coupled to an electrical generator, with a power output of 5 kW. The thermodynamic cycle is based on the organic Rankine cycle (ORC), and solar energy is used as a heat source. Besides the micro-turbine and generator, the system also includes a tank, condenser, heat-exchangers, pumps, hydraulic equipment and solar collectors (with operating temperatures lower than 100°C). For this analysis, the system is driven so that the heat from the condenser is totally used for heating purposes, in domestic applications. Energy savings derived from the use of the proposed system are quantified, as well as its environmental impact in terms of CO2 emissions.