Experimental evaluation of the concentrated solar heat flux distribution provided by an 8 m<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg" display="inline" id="d1e2506"><mml:msup><mml:mrow/><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup></mml:math> Scheffler reflector
Gabriel Guillet, J. Gaspar, Séverine Barbosa, Thomas Fasquelle, Benjamin Kadoch
Abstract
This study gives experimental results on the intensity and distribution of the concentrated heat flux delivered by an 8 m2 Scheffler reflector located in Marseille, France (lon. 5.4° E, lat. 43.3° N). Using thermography and inverse techniques, detailed maps of heat flux densities on a vertical screen were obtained at different times and on different days. The heat flux distributions provided were successfully fitted to a two-dimensional Gaussian model. The model parameters were used to objectively calculate, among other things, the mean major and minor diameters of the ellipse containing 99.7 % of the heat flux, i.e. 45 cm and 37 cm respectively. Maximum heat flux densities ranged between 81 kW m−2 and 112 kW m−2 and the total heat fluxes delivered by the reflector were between 2.4 kW and 3.2 kW, which led to energy efficiencies between 61 % and 67 %. The issue of repeatability of measurements and seasonal/daily variations is also discussed. The results of this study could serve as a basis for the development of realistic numerical models and be useful to engineers responsible for optimising systems incorporating a Scheffler reflector.