COOLISSE

Secondary refrigeration is an effective way to drastically reduce the quantity of primary refrigerant fluid used while improving energy efficiency by storing and transporting energy-dense secondary fluids. These ice slurries, made of ice crystals suspended in aqueous solution, are unfortunately not yet widespread due to an over-investment related to scraped surface or supercooling type generators. Within this COOLISSE project, our objective is thus to participate in the energy optimisation of the refrigeration sector by designing new type of ice slurry generators. Our aim is therefore to develop stainless steel surfaces where formed ice could be carried away by the fluid flow, without rotating scraper blades. These original non-wetting micro/nanostructured surfaces, inspired from nature, displaying anti-icing properties will be obtained by an original and efficient combination of processes: additive manufacturing (to yield micro-structures) and femtosecond laser ablation (to reach nanometer scale roughness) that will allow obtaining a multiscale and very dense textured stainless steel surface. These surfaces will be then infused by inert liquid in order to obtain slippery infused surfaces (SLIPS). The second objective of the project is to develop methods and expertise on the surface characterization under flow at low temperature [-15°C to 0°C]. The potential in anti-icing applications of the designed surfaces will be proven by investigating their action mechanisms on ice formation, analysing the freezing time, adhesion strength and nucleation in the freezing process. In parallel a comprehensive numerical method will be developed to describe the thermal equilibrium state, heat flux and gas-solid-liquid interface changes during freezing and phase change. The environmental impact and potential gain of these new surfaces on slurry fabrication process will also be compared to traditional processes using multiple criteria analyses like Life Cycle Assessment.