Construction and Thermal Analysis of a Parabolic Collector for Small Scale Concentrating Thermal System
Abstract
Few options are apparent for achieving a benign, sustainable energy future except those relying on the utilization of solar energy in one way or another (Kaneff, 2004). Experience with fossil and nuclear sources has revealed an array of unsolved problems of increasing concern as more evidence and understanding emerges (Quaschning, 2005). Africa has the world’s best solar resources. Several countries have exploited solar energy for water heating, crop drying, medical applications, and telecommunications, among other things (Davidson et al., 2007). Solar energy can contribute to supply heat energy in households of SubSaharan African countries. A small scale dish concentrating solar energy system is being developed at the Eduardo Mondlane University in Mozambique. The system comprises of the collector, the heat storage and the oven. The main structure of the system has been constructed, consisting of the dish reflector, the sun tracker and the piping mechanism. An infrared camera was used to scan the temperature of the concentrated heat. The maximum temperature reached so far is 350oC. The experimental focal area was found by mapping the reflections of the whole reflective surface. The shape of the receiver/absorber obtained by the scanning process is semi-spherical. 3D hemispherical absorbers with 110 mm < d < 220 m need to be used and investigated. The collector efficiency is too low.