Anti-ice: What´s possible? - What´s similar to other functinal coatings?

 
Anti-ice coatings can be based on different effects, such as low ice adhesion, the inhibition of freezing or the deceleration of the spreading of frost on a cold surface. The present paper discusses these concepts with respect to feasibility, exploitation for heating and ventilation equipment, and the relation between the respective anti-ice effect and the physical surface properties of a coating. The icing problems in focus of the present work were not the usual suspects such as airplane wings, wind turbine blades, or electrical power lines, but two specific heating and ventilation problems. The first is air-to-refrigerant heat exchangers of heat pumps using outside air as heat source (evaporator in fig. 1, fig. 2 shows a typical heat exchanger). The heat exchanger fins are cooled below 0°C when the outside temperature is below about 7°C. The second is air-to-air heat exchangers of heat recovery ventilation (HRV in fig. 1). At outside temperatures below about -3°C, the more humid outgoing air is cooled to temperatures below 0°C. In both cases, ice accumulates on the respective surfaces, impairing the heat transfer and requiring periodic defrosting by heating, thus consuming energy. Even if frost cannot be prevented completely, longer cycles between de-icing intervals would significantly safe energy.