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Anti-frost coatings to improve heat pump efficiency and adoption in cold climates

The use of heat pumps is becoming more common in residential buildings and newer electric vehicles (EVs) because of their dramatic potential to reduce greenhouse gas emissions. Air-sourced heat pumps (ASHP) are the most widely used type of heat pump because they combine precise temperature control with high energy efficiency and low initial installation costs.

The major barrier to utilizing ASHPs in colder environments is frosting, which occurs when surface temperatures drop to near or below zero. As with refrigerators and air conditioners, frost forms on the pump’s coil, forcing the pump to stop supplying heat and run the energy-intensive defrost mode. This process dramatically reduces the pump’s efficiency and capacity.

This project team has recently developed groundbreaking anti-frost coatings that delay the formation of ice on a coated surface by 2,000%. Their coatings have the potential to cut the energy needed for defrosting in half, cutting overall annual heat pump energy use by > 10%. Their project aims to improve the performance of these coatings, experimentally validate the improvements, and conduct a thorough techno-economic analysis to quantify the real-world impact of the coatings in different fields of use, including EVs and buildings.

The coatings being developed are made from bulk-scale, commercially available materials. They can significantly improve the energy efficiency of evaporator coils in refrigerators and air conditioners as well as heat exchangers in heat pumps, and will be of interest to a wide variety of potential commercial partners. In addition, the project will advance understanding of the process of frost formation on heat exchangers, as well as the economic benefits of making heat pumps frost-free.

University of Michigan - College of Engineering
U-M Graham Sustainability Institute
Research Areas
Energy Systems