Design and development of high performance concentrated solar collectors using passive and optical enhancement methods and nanofluids carrying absorber

With the rising concerns of fossil fuel usage and related environmental problems, the focus of global research is directed towards the development of methods utilizing renewable sources of energy and producing alternate fuels. Solar irradiation is a widely available source of free energy that can be harnessed to design a low-cost power production system. Concentrating solar collectors are promising devices to collect and transport solar energy for industrial processes and power generation. The concentrating solar collectors transform available solar energy into high-grade energy that can be transported at high temperature via heat transfer fluids such as thermal oils, molten metals, and salts. The solar collectors can be categorized as direct and indirect collectors. The direct absorption-based solar collectors have exhibited enhanced performance over the indirect collectors that consist of surface-based receivers. The last few decades have seen significant development in concentrating solar collector technologies and both Solar Tower Collector (STC) and the Parabolic Trough Collector (PTC) have been widely used in solar thermal applications. The non-uniformity of heat flux at the absorber has posed a great challenge to the safety of the system apart from exhibiting poor convection in the absorber tube. Further, the losses associated with the receiver has reduced the absorber efficiency significantly. The temperature uniformity of the absorber surface is inevitable to reduce the radiation and convection losses to the environment. The design modifications in the primary and secondary collectors can enhance the optical efficiency and create a more uniform heat flux at the tube surface. Further, the use of nanofluid as heat transfer fluid in the absorber can be used for enhanced energy transport, reduced temperature peaks and consequently reduced convective and radiation losses. These modifications need to be investigated in view of their applicability, safety, and techno-economic trade-off before proposing for commercial application. In view of the above-posed research issues, the proposed research is intended to design and develop an enhanced efficiency concentrated solar collector based on the synergetic effects of high optical efficiency of the reflectors, uniform flux, and temperature at the tube surface, minimizing, convection and radiation losses, and maximizing heat transfer through the absorber tube.