Scalable, Durable and Tunable Icephobic Coating for Air Cycle Machine Heat Exchanger

Condenser icing is a major limitation for an aircraft Environmental Control System (ECS). Frosting can occur on both hot-side and cold-side of heat exchangers, which can lead to significant decrease of thermal efficiency and increase of pressure drop. Hot-side frosting occurs as humid bleed air passing through the condenser, being cooled to below its dew point and condensing on fin surfaces. Cold-side frosting occurs due to impingement of supercooled droplets at the outlet of turbine. Advanced Cooling Technologies, Inc (ACT) in collaboration with Virginia Tech proposes to develop a novel icephobic coating for ECS condensers. The proposed coating technology is highly tunable such as a way that the coated icephobic surfaces can achieve different aspects of ice repellency, including supercooled droplet rebound, delay of freezing process, reduction of ice adhesion, etc. The proposed advanced coating is expected to be more durable than conventional superhydrophobic coatings (e.g. chemical vapor deposition) and lubricant-infused coatings and the procedure can be easily applied to larger surfaces without geometrical constraints. In Phase I, multiple coated coupons will be prepared and tested in a test chamber simulating hot-side and cold-side frosting conditions. The durability of the coating will be demonstrated in Phase I and the optimum coating recipes and procedure will be downselected for Phase II larger scale system development.