Efficiency Improvement of Direct Absorption Solar Collectors using Metallic Nanoparticles

Solar thermal collectors have various applications in water heating or space conditioning systems. Due to thelow efficiency of the conventional collectors, the researchers have presented some suggestions for improvement in thecollector efficiency. Adding nanoparticles to the working fluid in direct absorption solar collector, which has beenrecently proposed by some researchers, leads to improvement in liquid thermal and optical properties such as thermalconductivity and absorption coefficient. This results certainly in collector efficiency enhancement. In this paper, radiativetransfer and energy balance equations are numerically solved and the effect of different metallic nanoparticles on thecollector efficiency is investigated. It was found that under similar operating conditions, the presence of Aluminumnanoparticles increases the collector efficiency by about 15% compare to a flat-plate collector. This improvement isaround 7% for silver and gold nanoparticles.

کلیدواژه ها:

Metallic Nanoparticles ، Solar Energy ، Direct Absorption