Thermal Management of Electronics from Device Level to Data Centers

Damena Agonafer, PhD
Associate Professor
University of Maryland

Abstract: Thermal management is vital for ensuring the reliable operation of semiconductor and integrated circuit devices. As device performance and complexity continue to rise, developing advanced cooling solutions and precise thermal characterization under varied operating conditions becomes increasingly critical. At the Nanoscale Energy and Interfacial Transport Lab (NEIT Lab), we lead several research efforts on thermal characterization and innovative cooling strategies for electronic systems. A significant initiative involves developing a pumped two-phase evaporative cooling system, bridging fundamental studies of microdroplet evaporation with system-level applications in servers and data center racks. Based on the nonequilibrium Gibbs criterion, we conducted a combined theoretical and experimental study on how evaporation and surface roughness affect the critical contact angle for droplet pinning. Our findings show that increased surface hydrophobicity raises the critical angle during evaporation, leading to a revised criterion for predicting pinning across various surfaces and coolants. These insights directly informed the design and testing of direct-to-chip evaporatively cooled cold plates using water and dielectric fluids, capable of handling heat fluxes over 560 W/cm²—offering a practical, scalable solution for cooling high-power components in next-generation data centers. Our lab is also focused on the development of a novel pseudo-two-phase cooling approach using encapsulated phase change material (PCM) slurry—created by dispersing micro-encapsulated PCMs in dielectric coolants—and assessing its performance in enhanced micro/mini channel designs through experimental setups. This approach overcomes the caloric resistance limitations of conventional coolants by significantly boosting overall heat capacity via the latent heat of the PCM. Beyond cooling solution development, we actively engage in the thermal characterization of transistor-level heat management. Leveraging advanced techniques such as Microsanj imaging and steady-state thermoreflectance, we analyze multilayer structures and wide-band-gap devices like GaN, measuring thermal conductivity and interfacial thermal resistance through both steady-state and transient experiments to evaluate performance under diverse operating conditions. Our group addresses co-design challenges in the 3D heterogeneous integration of electronic chips by holistically considering electrical, mechanical, and thermal aspects. We utilize advanced heat spreaders like boron nitride and implement high-performance thermal management techniques, including novel two-phase flow boiling systems to manage non-uniform and transient heat loads. Site-specific thermal requirements and heat maps guide optimization, enabled through comprehensive data-driven models developed using advanced measurement and image processing techniques. Additionally, our lab is developing software tools powered by physics-informed neural networks (PINNs) to construct digital twins of data centers, enabling accurate and cost-effective performance prediction for single and two-phase operations. The PINN model is also applied to build high-fidelity thermal models of GaN/HEMT transistor-level devices.Beyond electronic component cooling, we are advancing rotary desiccant-based dehumidification systems to enhance HVAC and data center efficiency through improved moisture control and energy performance.

Biography: Dr. Damena Agonafer is an Associate Professor & Inaugural Clark Faculty Fellow in the University of Maryland College Park Mechanical Engineering Department. In 2025, he received the prestigious Presidential Early Career Award for Scientists and Engineers (PECASE), the highest honor for early career scientists. Professor Agonafer’s research interests lie at the intersection of thermal-fluid sciences, interfacial transport phenomena, and renewable energy. He focuses on developing novel materials and systems for the thermal management of power and microelectronic systems and for thermochemical and electrochemical energy storage applications. He aims to achieve transformational technological advancements by tuning and controlling solid-liquid-vapor interactions at micro- and nano-length scales. Specific focus areas include developing unique materials and micro-/nanostructures for phase change heat transfer, thermochemical energy storage, and interfacial transport phenomena. The applications of his work encompass cooling high-powered electronics, managing battery thermal performance, cooling data centers, and enhancing the efficiency of HVAC systems. Professor Agonafer earned his PhD at the University of Illinois Urbana-Champaign, where he was supported by the Alfred P. Sloan Fellowship, Graduate Engineering Minority Fellowship, and the NSF Center of Advanced Materials for Purification of Water with Systems (WaterCAMPWS). After completing his PhD, Damena joined Professor Ken Goodson’s Nanoheat lab as a Stanford University Postdoctoral Scholar in the Mechanical Engineering Department. He has received several awards, including the Google Research Award, Sloan Research Fellowship, Cisco Research Award, NSF CAREER Award, ASME Early Career Award, and ASME K-16 Outstanding Early Faculty Career in Thermal Management Award. Furthermore, he was one of 85 early-career engineers selected in the US to attend the 2021 National Academy of Engineering’s 26th annual US Frontiers of Engineering symposium. He also serves as a site lead for a newly formed Environmental Refrigerant Technology Hub NSF Engineering Research Center (ERC) focused on creating a “sustainable refrigerant lifecycle” to address technical, environmental, and societal challenges facing the HVACR industry.