Utilizing Hybrid Nanofluids to Analyze the Thermal Performance of a Solar Flat Plate Collector

Effective utilization of solar energy in industrial application is a challenging task today. Solar energy is used in many applications such as water heating, drying of grains, room heating and cooling, process heating in industries, etc. Solar flat plate collector is one of the devices used as water heater in industrial applications.However, efficiency of the collector is limited while using conventional fluid as working medium since the efficiency of the collector depends on absorption properties of the working fluid. The efficiency of the collector can be enhanced by using nanofluid as working medium. As nanofluid is a colloidal suspension of ultrafine particle with base fluid, the pressure drop across the collector also increases which leads to high operational cost.Hence, an attempt was made in this work to find optimum value of heat transfer rate, collector efficiency and pumping power by mixing CuO and Al2O3 nanoparticle in base fluid, former possesses high thermal conductivity and later possesses moderate thermal conductivity but cheaper than former. Hybrid nanofluids were prepared with 0.1%, 0.2% and 0.3% by volume concentration with equal volume proportion of CuO and Al2O3 nanoparticle.  Example, for 0.1% nanoparticle concentration, 0.05% CuO and 0.05% Al2O3 by volume is blended and mixed with distilled water and the same methodology is followed to prepare 0.2% and 0.3% nanoparticle concentration. Prepared nanofluid with different nanoparticle concentration were tested with three mass flow rates such as 0.016kg/s, 0.033kg/s and 0.05kg/s.Based on the experimental result, the outlet temperature, heat transfer rate, collector efficiency, pressure drop across the collector, pumping power, Nusselt number and friction factor were analyzed and compared with water.The current experimental work shows hybrid nanofluids provide optimum heat transfer characteristics, minimum pressure drop and less operational cost.