Performance enhancement by utilization of nanofluids in solar collector for application in high performance buildings

Given the potential risks associated with the use of fossil fuels, there has been a recent emphasis on the adoption of environmentally friendly and highly potential renewable energy sources. Solar energy stands out among these sources due to its global accessibility, limitless potential, and versatility in conversion into various forms of energy. Solar collectors, designed to absorb incoming solar radiation and convert it into heat, represent the most efficient and widely utilized devices in the realm of solar technologies. In various applications, particularly in thermal contexts, flat plate solar collectors are the preferred choice due to their ease of design, durability, and cost-effectiveness in maintenance. Traditional liquids such as air, water, ethylene glycol, and oil, employed for heat transport in collectors, exhibit low thermal conductivity, limiting their ability to facilitate high heat transfer. To enhance the thermal efficiency of flat plate solar collectors, common strategies include passive geometric modifications and the utilization of nanofluids, which offer superior heat transfer and absorption capabilities compared to conventional fluids. In this study, with the support of Cankaya University Scientific Research Projects (BAP) Coordination Unit, thermal analysis of the solar collector system is done for different nanofluids by synthesizing nanofluid to be used in the manufactured flat plate solar collector system which will be integrated into high-performance buildings. The design parameters of the collector and the impact of utilizing nanofluids on the thermal efficiency of collector systems are investigated through both analytical and experimental approaches. Performance analyses are conducted for various nanofluids with different concentrations serving as the heat transfer fluid. Results of the analysis show that, nanofluids synthesized show serious improvements in thermo-physical properties. In this way, fluids have a much higher heat transportation capacity which directly increases the overall efficiency of the collector system. When a comparison of the thermal properties of commonly used oxides (AL2O3) and rarely used nitrides (AlN) in the literature are conducted, AlN based nanofluids are found to have better thermal properties resulting higher collector system efficiency then the AL2O3 based ones. Additionally, when the application of MAX (Ti3AlC2) synthesized using Titanium (II) hydride Mxene as a nanofluid is implemented, performance enhancement in the solar collector system is found to be higher than both AlN and AL2O3. When the experimental results are compared, an increase of 4.2%, 7.4%, 26.2%, 34.1%, 51.4%, and 55.3% was observed in the efficiency of the collector compared to water, respectively.