Characterization of Clay and Granite Dust Blends as Novel Materials for Energy Storage and Diffuser in Constructing Flat-plate Solar Collector

Sun is the main source of solar energy, and the energy it releases to the Earth’s surface in one hour is more than what the whole planet consumes in a year. This present work is about characterizing novel material that can be used as energy storage and diffuser in constructing flat plate solar collector. Materials used are clay and granite dust obtained from Okelele and Kulende Quarry sites, both in Ilorin, Kwara State, Nigeria. The materials were sun-dried; the clay crushed before the two materials were sieved into different particle sizes. They were thereafter blended into different ratios and then characterized for thermal, physical and mechanical properties. Results showed that the highest thermal conductivity, thermal diffusivity and compressive strength were obtained from sample of particle size 0.075 mm and clay: granite ratio 50:50 (0.268176 W/mK, 3.58514 10–4 m2/sec and 3.571 N/m2, respectively). This same blend has a density of 0.91 g/cm3 and specific heat capacity of 824 J/kgK. This sample, having the optimal thermal, physical and mechanical properties will be a good replacement for conventional insulating materials currently being used for solar flat-plate collector construction as it will serve as both energy storage and diffuser. Keywords: Solar energy; solar collector; insulating material; clay; granite dust; thermal conductivity; thermal diffusivity