NOVEL CONVECTION PROCESS: EXPERIMENTAL STUDY OF A SOLAR CHIMNEY WITH ITS COLLECTOR MADE OF HEMISPHERICAL CONCENTRATORS

This paper presents an experimental study of a solar chimney. The prototype is made with a collector of 2.00 x 2.00 m2 , and a chimney of 20 cm of diameter and 2.00 m of height. The collector, in accordance with a novel natural convection process based on the hot spot theory, is made of 49 hemispherical concentrators of 28 cm of diameter. The experimental study focused on temperatures measurement along the radius of the collector for a measured insolation of the day, and comparison with a similar solar chimney with usual black-painted absorber. As a result, for three day measurements taken in different cloudy or clear sky conditions and from 8:00 am to 4:00 pm, the shape of the evolution of temperatures along the radius of the collector suggests that the new system could best replace systems with absorbers by guarantying the outlet temperature, allowing more air through its collector and consequently reducing the usual size of solar chimney collectors.