Study On The Absorption And Application Of Nanofluids To Solar Energy

The use of traditional fossil fuels has created more and more problems for human society,and the use of sustainable energy has also become an important issue.In the sustainable energy,solar energy has become a research focus because of its wide distribution,security and other characteristics.In this thesis,carbon nanotube nanofluids were prepared by two-step method.The dispersibility of carbon nanotube particles in water was improved by stirring,ultrasonic shock and dispersant.The effects of different dispersants on the stability of nanoparticles were compared.Based on the preparation of stable Carbon-nanotube nanofluids,the radiation characteristics of nanofluids were measured and compared by Surface-Enhanced Raman Scattering and spectrophotometry.In the experiment,the optical path and the concentration of the nanofluids were changed,and the transmittance parameters of the nanofluids were measured to characterize the absorption characteristics of the nanofluids.Based on the direct absorption concept,the nanofluids optical and thermal conversion characteristic test bed was set up.Under the natural light condition,the solar collectors with carbon-nanotube nanofluids were placed outdoors.The photothermal conversion characteristics of nanofluids at different concentrations were compared as well as the light and heat conversion efficiency.The results show that the addition of a small amount of carbon nanotube particles in water can greatly improve the absorption of light from the nanofluids.The photothermal conversion efficiency of the nanotube nanofluids decreases with the increase of the mass fraction,and the highest is 29.90%.At the end of this thesis,the concept of solar energy utilization is used to combine the direct absorption solar collectors and solar panels.We designed a thermoelectric power system.The influence of the concentration and the thickness of the nanofluids layer on the system is analyzed.