Design and performance study of a parabolic Fresnel hybrid solar collector

Abstract

The need for energy is increasing globally as population and consumption increases, while at the same time resource depletion is causing supply-demand gap. Fossil fuels are the major energy resources but are also responsible for many environmental impacts including climate change. The need to increase energy production and reduce environmental impacts requires the energy sector to transition towards renewable energy like solar, wind, etc. Solar thermal is one of the major renewable energy sources and can provide energy in the form of both heat and electricity. It can be used for domestic and industrial applications with varied degree of decentralization. The major roadblock to the large-scale adoption of solar energy is the cost, while the conventional energy from fossil fuels is cheap. To compete and gain wide acceptance the cost of solar systems has to decrease or the efficiency must increase. Parabolic Trough Concentrator (PTC) and Linear Fresnel Concentrator (LFC) are the two major solar thermal technologies. While PTC is highly efficient it has high initial and overall cost, LFC is cheaper with low efficiency. The LFC has two major design advantages; they are the use of nearly flat mirrors and stationary absorber. This work focusses on combining these two features in a system with the high efficiency of a parabolic collector. A hybrid collector called Hybrid Parabolic Linear Fresnel Collector (HPLFC) with flat plates whose midpoints are pivoted on a parabolic profile with a stationary absorber has been proposed and investigated. A novel tracking system controlling all the flat plates with a single mechanical link has been designed and tested. The investigation of the HPLFC has been carried out with an analytical model developed using Scilab and an optical model has also been developed with SolTrace. newline