Working Fluid Enhancement for a Solar Water Heater System towards Hawaii with Nanofluids

In a thermal energy storage system, the ability to harvest heat is vital. Hawaii’s plan to transition to clean energy is by the year of 2045 <b>[1]</b>. This introduces to optimizing a solar water heater system towards Hawaii’s climate. As Hawaii is in the tropical region where abundant solar energy is available yearly, we can achieve decarbonization and help transition to renewable energy before 2045. Some of the prior works toward enhancing a solar water heater system focuses on enhancing the solar absorber’s material. However, impact of the working fluids on the indirect solar water heater system has gained less attention. Conventional working fluids lack in their thermophysical properties that lead into poor heat transfer towards energy conversion systems. Here, I introduce to use nanofluids to overcome this issue and enhance the heat transfer of the solar water heater system. Nanofluids are engineered colloidal suspended solutions that enhances the overall heat transfer of the base liquid. Nanofluids are well known for their enhanced thermal conductivity in which they’re reliant on the nanoparticle’s material, size, and shape. I have also developed a transient hot wire apparatus to measure nanofluid’s thermophysical properties to help determine the best selected enhanced working fluid from the innumerable samples. The nanomaterials used are multiwalled carbon nanotubes, alumina, copper oxide, and silver nanoparticles. I will present the obtained thermophysical properties of the water based nanofluids and compare their results with water to demonstrate the thermal conductivity enhancement. I will also present the overall efficiencies of the solar water heater system with the selected nanofluids to illustrate how the heat transfer has been enhanced. We expect these results to be valuable in understanding the energy conversion enhancement of a solar water heater system to achieve decarbonization and enable sustainable energy for Hawaii before 2045.<br/><br/><b>[1]</b> Borland, J., & Tanaka, T. (2018, June). Overcoming barriers to 100% clean energy for Hawaii starts at the bottom of the energy food Chain with residential Island Nano-grid and everyday lifestyle behavioral changes. In 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC)(A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) (pp. 3829-3834). IEEE.