Committee Members:

Prof. Shannon Yee, Advisor, ME/MSE

Prof. Kyriaki Kalaitzidou, Co-advisor, ME/MSE

Prof. Natalie Stingelin, MSE/CHEM

Prof. Baratunde Cola, ME/MSE

Jaswinder Sharma, Ph.D., Oak Ridge National Laboratory

"Understanding Heat Management Enabled by Silica Based Insulating Microstructures and Dielectric Mirrors"

Abstract:

Due to increasing average global temperatures, the energy used for space cooling in buildings will increase nearly 300% by 2050 and account for 13% of all electricity usage worldwide. Consequently, to meet global cooling demand, fossil fuels and refrigerants will be used at higher rates, both of which release carbon dioxide and volatile chemicals with large global warming potentials. This increase in greenhouse gas emissions thus results in a growing and autocatalytic demand for space cooling. To mitigate greenhouse gas emissions and reduce the need for space cooling, the thermal properties of materials can be engineered to reduce the thermal load on buildings. Therefore, in this talk, I will present on the theoretical framework, synthesis, and characterization of super insulating, low emissivity, and dynamic switching thermal materials that can reduce thermal loads on buildings and reduce our greenhouse gas emission and need for space cooling.

Specifically, in this talk and in my thesis, I addresses four distinct thrusts that increase the scientific knowledge of these thermal materials and our ability to better thermoregulate buildings. First, I will present a parametric study on the effective thermal conductivity of hollow sphere silica nanoparticles (HSNPs), which are used to improve the thermal insulation of buildings. Second, I will build upon the first thrust and quantify how ternary composites consisting of HSNPs with carbon fillers affects a building's radiative building insulation. Third, I will characterize the mechanism and degree of switchability achieved by polymer dielectric mirrors, which can be coated on windows and used to reflect solar radiation over a tunable range. Lastly, I will present in-situ measurements used to characterize the dielectric mirror's dynamic thermal conductivity and optical reflectance as a function of chemical state and humidity. Ultimately, this thesis provides a deeper understanding of the relationship between HSNP designs and their insulation performances and extensively examines the switchability of dielectric mirrors used for dynamic thermal conduction and radiation management.