Computational methods for analysis and optimization of solar thermal energy collection and storage technologies

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The global demand for energy continues to increase rapidly, despite the fact that greenhouse gas emissions from energy production pose an increasingly urgent threat to the environment. While the renewable energy sector has grown significantly in recent years, and now makes up 14% of the total energy supply, this growth must be sustained in order to meet new targets for greenhouse gas emissions. Most of the current renewable energy mix is made up of hydroelectric, biofuels, and waste, while geothermal, solar, wind, and heat energies still account for less than 2% of the total energy supply. The relative absence of solar energy is particularly intriguing, given that the sun delivers many times more energy to the earth than what is needed to satisfy society's energy needs.The proposed research program focusses on the development of computational tools that will enable design and optimization of better devices for capturing and storing solar thermal (heat) energy. The fact that solar thermal energy is only available during daylight hours is a key factor that may limit its widespread use. Similar to using batteries to store electrical energy, thermal energy can also be stored by certain materials, known as phase change materials. Phase change materials store energy in the form of latent heat during a phase change process, such as melting. During a melting process, the temperature of a material does not change but it absorbs a large amount of energy, which can later be recovered by solidifying the material. One major issue is that phase change materials typically have very low thermal conductivity and therefore require a long time to store and later recover heat energy. Through this research program, the thermal conductivity of phase change materials will be enhanced by embedding a highly conductive porous solid with very high internal surface area for heat convection. Numerical simulations will be conducted to determine the optimal pore shapes and sizes to maximize the heat transfer enhancement. The use of nanofluids (i.e. high-conductivity nanoparticles suspended into the phase change material) is also known to enhance thermal conductivity and will be investigated numerically in this work. In addition to storage of thermal energy, the capture of thermal radiation will be studied. Enhancements obtained using porous materials (to enhance thermal conductivity and convection area) and nanofluids (to improve optical absorbance properties) will be quantified and optimized.The result of this research program will be a significant library of computational tools that will serve as an excellent design and optimization platform for the development of enhanced solar thermal collection and storage devices, as well devices for other energy applications. The software tools will be released to the public as open source, with the goal of creating a multi-institutional platform for collaboration.