Utilization of nanofluid in various clean energy and energy efficiency applications

Abstract

Policy makers around the globe, both at the national and international level, have been emphasizing on energy efficiency and utilization of alternative clean energy technologies by replacing fossil fuel as a primary source of energy. This interest was initiated when the adverse effects of fossil fuel on the environment such as greenhouse gas emission and global warming were unfolded. Multidisciplinary researches are being carried out in the research laboratories to provide effective clean energy solutions. Nanofluid, a colloidal mixture of nanoparticles in the base fluid, e.g., water, ethylene glycol, oil, offers efficiency improvements in many clean energy applications due to the improvement in its thermophysical property. In this chapter, use of nanofluid in various clean energy and energy efficiency applications is reviewed. Solar energy, the dominant clean energy source, is a potential field of application where nanofluid can be employed. Solar thermal collectors and solar water heaters are the ideal candidates for utilization of nanofluid for improving solar to thermal energy conversion. Thermal storage system employs phase change material (PCM) for storing thermal energy, and nanofluid may be added to the PCM for enhanced performance. Nanofluid can be used in carefully designed heat exchangers for extracting energy from geothermal resources. This mixture can also be used in waste heat collector to improve efficiency for its thermophysical property causing a heat transfer enhancement. Adding nanoparticles to the refrigerants improves the heat transfer characteristics of refrigerants and improves the performance of the refrigeration system from an energy efficiency perspective. However, there are challenges associated with nanofluid which are needed to overcome for optimal performance of the working fluid.