A Kinetic Surface Refrigerator: Cooling via Selective Normal-Momentum Dissipation at a Nanostructured Membrane

We propose a non-cyclic cooling mechanism based on the selective dissipation of the normal component of kinetic energy during molecular impacts on an atomically thin, impermeable membrane. A suspended two-dimensional membrane — such as graphene or h-BN — selectively dissipates the perpendicular velocity component of impacting gas molecules while preserving the parallel one. A "suction-cup" variant with transient adsorption sites captures molecules and releases them with half their initial kinetic energy. Patent pending — Italian patent application n. 102026000021628, filed 23 July 2026.