Low temperature and power solar energy conversion for domestic use

This article summarizes the design, the manufacturing and the testing of a small scale Organic Rankine Cycle using Concentrated Solar Power as the heat source. First, the choice of the nominal point of the cycle is detailed, including the operating environment of the ORC (characteristics of the solar field and ambient temperature) and the constraints of operation. The paper presents the design of a radial turbine with a power of 3 kW and the numerical simulations of flow in the fluidic part of the turbine (nozzle, wheel etc). It also deals with system engineering, the calculation and the selection methodology of main components such as exchangers, pumps, and sensors.

In the second part, the results of the laboratory tests is presented. The experiment was performed using as hot source, a thermal oil boiler. The analysis of the results shows isentropic efficiency around 40% on a rather large range of pressure drop, and a cycle efficiency of 5 % which, is encouraging in view of the first test conditions.