Design of an ORC system operating with solar heat and producing sanitary hot water

Organic Rankine Cycle (ORC) is useful to generate electricity from low temperature sources such solar heat (< 120 degrees C). An ORC system, working with R-245a, is presented and analyzed. The system provides the required electric power and the required hot sanitary water of a typical dwelling during one day (24 hours). The system operates between a cold source of 25 degrees C and a hot source : water at 120 degrees C in solar hours, when solar flux is available, and between a cold source of 15 degrees C and a hot source : water at 98 degrees C coming from the accumulation tank in no-solar hours (morning, evening, and night). The maximum generated electric power is 2000 W, and the used daily hot water is 200 l at 60 degrees C. The required surface of the solar heater is 100 m(2) assuming 8 solar hours per day and a mean solar flux of 400 W/m(2). The advantages of the ORC system are the electricity generation, the hot water production and the low cost compared to photovoltaic electric power generation. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [name organizer]