θ LAB

Recent advancements in micro/nanofabrication have introduced new techniques for creating and characterizing materials, enabling the study of transport phenomena across various engineering disciplines. Nanotechnology has shown significant potential, particularly in the development of micro/nanostructured surfaces for phase change heat transfer applications, such as boiling, evaporation, condensation, and freezing. These innovations are critical for high-heat-flux electronics cooling, desalination, and industrial power generation. Researchers have successfully controlled droplet nucleation on hybrid or biphilic surfaces, which combine hydrophobic and hydrophilic properties, enhancing fog harvesting, heat transfer, and icing prevention. However, current fabrication techniques face challenges, including scalability, high costs, and a lack of optimized design guidelines. Our work focuses on developing scalable, efficient fabrication methods and improving numerical models to better predict the performance of these surfaces in phase change applications, ultimately contributing to improved energy efficiency in thermal systems.

Surface functionalization through coatings has diverse applications, including phase change heat transfer in HVAC systems, anti-fouling in various transportation sectors and buildings, and electronics cooling. However, a significant challenge in the industrial adoption of these functional surfaces is their long-term durability. For instance, in the power plant industry, applying chemical coatings to make condenser units hydrophobic can enhance efficiency by up to 2%, reduce greenhouse gas emissions, and lower the levelized cost of electricity (LCOE) by 1.9%. Despite these potential benefits, the long-term durability of hydrophobic coatings is not yet proven, which limits their industrial use. Additionally, while traditional functional surfaces perform well with low surface tension liquids and refrigerants, there is a pressing need to develop more durable surfaces for these applications to improve energy efficiency. This need extends to low-temperature applications, such as surface icing and frosting. Our research focuses on understanding the degradation mechanisms of surfaces in these conditions—steam condensation, low surface tension liquids, refrigerants, and icing/frosting environments. With this knowledge, we are working on developing durable surfaces for various energy applications, including power generation, HVAC systems, transportation (marine, aviation, etc.), and electronics cooling.

Poor thermal management of electronics not only reduces device performance but also significantly shortens their lifespan, with 55% of power electronics failures attributed to elevated temperatures. As power densities increase, with localized heat fluxes reaching up to 1 kW/cm², effective thermal control has become critical. Current thermal management schemes often rely on thermal interface materials (TIMs) to provide mechanical compliance and electrical isolation. However, TIMs typically suffer from poor thermal conductivity, limiting heat transfer efficiency. Additionally, achieving proper electro-thermal co-design for improved performance is not always guaranteed, which can reduce system-level reliability or even cause failure in high-power-density applications, such as heavy-duty vehicles and electric aircraft. Our work addresses these challenges by developing advanced thermal management solutions through precise modeling and optimization, with a strong emphasis on electro-thermal co-design. We aim to create lightweight, durable thermal solutions that enhance volumetric and gravimetric power density while improving overall system-level reliability.

Thermal management is also a major bottleneck in increasing the computational performance of modern data centers, affecting both density and efficiency. Data centers currently consume 2% of U.S. electrical energy, with projections suggesting this could rise to approximately 10% by 2030. Cooling systems account for about 45% of this energy use, significantly contributing to carbon emissions. Liquid immersion cooling has emerged as a key method for efficient heat removal in data centers and other thermal systems. However, traditional cooling solutions often face limitations due to inadequate surface design and the performance or environmental impact of conventional coolants. To address these issues, our research focuses on developing eco-friendly cooling architectures that integrate sustainable coolants with advanced surface engineering. We combine innovative metrology, multi-dimensional surface architectures, and durability assessments under diverse working conditions to create high-performance, sustainable cooling solutions.

Extreme weather events, such as unexpected snow, frost, and ice accumulation, are becoming more frequent in regions that historically have not experienced them. These conditions pose significant challenges for electrified systems, both stationary and mobile, by affecting performance and reliability. In particular, the aviation industry’s shift toward electrification offers reductions in emissions and noise, but electrified aircraft are especially vulnerable to icing. Ice accumulation diminishes energy efficiency and compromises aerodynamic lift, and unlike internal combustion engine (ICE) aircraft, electrified aircraft lack onboard mitigation strategies, such as hot exhaust gases or readily available power for de-icing systems. To address these challenges, our work focuses on developing rapid, energy-efficient de-icing and defrosting strategies that can be applied to electrified aircraft and HVAC systems. By leveraging fundamental research in surface design and phase change phenomena, we are also creating waste heat recovery systems and thermal storage devices to improve system efficiency and enhance overall sustainability.

To achieve higher energy efficiency, energy systems must undergo transformative changes. This transformation requires the development of novel system architectures that focus on multi-level modeling and optimization while minimizing capital and operational costs. For example, integrating hydrophobic coatings and surface structures on metallic condensers can significantly enhance system performance. However, traditional materials often contain environmentally harmful perfluorinated compounds and lack durability. Currently, no highly durable hydrophobic coatings exist, and developing such coatings could be transformative due to their potential chemical stability and longevity in harsh environments. Our work leverages data-driven approaches to gain a fundamental understanding of novel material families through property prediction and performance evaluation. Additionally, there is limited data on the practical impact of hydrophobic coatings at larger scales. To address this, we develop dynamic system models to assess the benefits of implementing these advanced surface technologies. This approach can be extended to diverse energy systems, enabling the creation of performance prediction models that prioritize energy efficiency, durability, and techno-economic feasibility. These insights hold significant potential for optimizing system performance and advancing sustainable energy solutions.