As the demand for sustainable energy solutions continues to surge, V.K. Kukkapalli, a distinguished researcher, has made groundbreaking advancements in roadway embankment stabilization and metal hydride reactor design optimization. His pioneering research focuses on thermal management techniques, presenting innovative approaches to enhance infrastructure development in cold climate regions and improve the efficiency of hydrogen storage systems.
In a recent publication in the Journal of Mechanical Science and Technology (2021), Kukkapalli’s research centers around the optimal design of thermosyphon evaporators for roadway embankment stabilization in arctic regions. Thermosyphons are currently utilized in roadway embankments to prevent permafrost thawing by rejecting heat during the cold season, thereby maintaining the ground temperature below freezing. However, the high installation costs associated with this technology have limited its widespread use. Through meticulous numerical investigations conducted in collaboration with Dr. Sunwoo Kim, Kukkapalli explored the spacing between neighboring thermosyphons to identify the optimal design. The results demonstrated that a spacing of 5.5 m for parallel and one-bifurcation level Y- and T-shaped evaporators, and 7.0 m for two-bifurcation level Y- and T-shaped evaporators, optimizes the ground temperature. Notably, the two-level bifurcated Y-structure thermosyphon exhibited a remarkable 13% improvement in hot spot temperature compared to conventional thermosyphons.
In another significant study published in Energies (2022), Kukkapalli tackled the challenges associated with metal hydride reactors used for hydrogen storage. Metal hydrides offer numerous advantages such as room temperature hydrogen storage and reduced volume requirements in comparison to traditional gas tanks. However, the slow charging process and the need for efficient thermal management have hindered their widespread implementation. Kukkapalli and his colleagues developed a metal hydride reactor model using COMSOL Multiphysics software, focusing on optimizing the cooling channel design. Their study demonstrated that incorporating phase-changing coolant and varying convection coefficients along the length of tubes significantly reduces the hydrogen charging time and peak reactor temperature. By integrating fins and increasing the number of passes, their research achieved a remarkable 56% to 68% reduction in charging time compared to tube-only configurations. Notably, 6-, 9-, and 12-pass heat exchangers recorded charging times of less than 10 minutes.
Furthermore, Kukkapalli’s comprehensive review paper titled “Thermal Management Techniques in Metal Hydrides for Hydrogen Storage Applications” (Energies 2023) consolidates the latest advancements in thermal management methods for metal hydride systems. The review encompasses various techniques such as optimized reactor vessel shapes, heat exchangers, phase change materials, nano oxide additives, cooling tubes, water jackets, and high thermal conductivity additives. This review provides crucial insights into performance comparisons and assists researchers in selecting suitable thermal management techniques. By analyzing hydrogen adsorption time relative to reactor size and the amount of hydrogen absorbed, the review serves as a valuable guide for further exploration and development of effective thermal management techniques for metal hydrides.
The findings from Kukkapalli’s research papers hold immense importance for current practices in infrastructure development and hydrogen storage applications. Implementing the optimized designs for roadway embankments has the potential to enhance thermal management, stability, and longevity, effectively addressing the issues associated with permafrost thawing in cold climate regions. Similarly, the improved efficiency and reduced charging times in metal hydride reactors pave the way for enhanced performance, cost-effectiveness, and practical deployment of hydrogen fueling systems.
V.K. Kukkapalli’s groundbreaking studies signify a remarkable contribution to the fields of thermal management and sustainable energy solutions. By pushing the boundaries of infrastructure development and hydrogen storage, his research propels us closer to a more resilient and sustainable future.
Temperature profiles of the 6-passes tube Metal Hydride Reactor without fins (top) and with fin (bottom), Scale in Kelvin.
Surface temperature (K) profile for second bifurcation for Y shaped tree architecture thermosyphon design for arctic roadway embankment model.
Mr. Kukkapalli and colleagues published their study in below journals:
Kukkapalli, V.K., Kim, JH. & Kim, S. Optimum design of thermosyphon evaporators for roadway embankment stabilization in the arctic regions. J Mech Sci Technol 35, 4757–4764 (2021). https://doi.org/10.1007/s12206-021-0941-1
Keith, M.D.; Kukkapalli, V.K.; Kim, S. Phase Change Cooling of a Metal Hydride Reactor for Rapid Hydrogen Absorption. Energies 2022, 15, 2490. https://doi.org/10.3390/en15072490
Kukkapalli, V.K.; Kim, S.; Thomas, S.A. Thermal Management Techniques in Metal Hydrides for Hydrogen Storage Applications: A Review. Energies 2023, 16, 3444. https://doi.org/10.3390/en16083444
For additional information, contact [email protected], Vamsi Krishna Kukkapalli, Dept. of Mechanical Engineering, University of Alaska Fairbanks, Fairbanks, Alaska, United States.
