EPFL Mechanical Engineering Colloquium

Srinivas Garimella discusses how insights into phase-change heat and mass transfer and innovations in heat-driven cycles can complement renewable electricity in decarbonisation. He presents sorption-based space conditioning driven by renewable energy or waste heat, including waste-heat-driven sorption heat pumps for cooling in severe climates at kW to MW scales; heat pumping for commercial dryers; diurnal and seasonal thermal storage; thermochemical adsorption storage to support vapour-compression heat pumps; and adsorption chillers driven by biomass, solar or waste heat for cold chains where electricity is unreliable. He also outlines combined space conditioning and water purification, power plant cooling without water-intensive towers, next-generation nuclear reactor designs, sorbent-loaded microchannel fibres for carbon capture, and water and energy conservation in aluminium ingot casting.

Yifan Wang presents approaches to robotic materials that are soft enough to deform, adapt and interact safely yet strong enough to carry loads and do useful work, by programming material architecture, connectivity and active response across scales. Geometric and topological design overcomes the trade-off between shape morphing and stiffness: scale-inspired layered structures combine complex deformation with controllable load bearing, and topologically interlocked fabrics use collective interactions and jamming to switch from conformable sheets to stiff structures. Active fibres and hierarchical tessellations enable programmable three-dimensional morphing and customised human assistance, and granular metamaterials with reconfigurable bonds assemble, disassemble and rearrange for adaptive mechanical and robotic functions. Coaxial direct ink writing embeds conductive pathways, dielectric insulation and actuation in three-dimensional structures, yielding electrostatic fibres and lattices for programmable clutches, shape morphing, artificial muscles and swimming robots.