Energy cost based design optimization method for medium temperature CPC collectors Free

CPC collectors, approaching the ideal concentration limits established by non-imaging optics, can be designed to have such acceptance angles enabling fully stationary designs, useful for applications in the low temperature range (T < 100°C). Their use in the medium temperature range (100°C < T < 250°C) typically requires higher concentration factors in turn requiring seasonal tracking strategies. Considering the CPC design options in terms of effective concentration factor, truncation, concentrator height, mirror perimeter, seasonal tracking, trough spacing, etc., an energy cost function based design optimization method is presented in this article. Accounting for the impact of the design on its optical (optical efficiency, Incidence Angle Modifier, diffuse acceptance) and thermal performances (dependent on the concentration factor), the optimization function integrates design (e.g. mirror area, frame length, trough spacing/shading), concept (e.g. rotating/stationary components, materials) and operation (e.g. O&M, tilt shifts and tracking strategy) costs into a collector specific energy cost function, in €/(kWh.m²). The use of such function stands for a location and operating temperature dependent design optimization procedure, aiming at the lowest solar energy cost. Illustrating this approach, optimization results will be presented for a (tubular) evacuated absorber CPC design operating in Morocco.