Advanced Condensers Utilizing Microchannel Evaporator Networks (ACUMEN)

Described is a highly compact two-phase microchannel condenser concept based on a two-phase loop evaporator design developed for cooling high performance servers in racks on Navy ships/submarines, a novel design that has demonstrated open-air evaporative heat transfer coefficients with water of 250,000 W/m2 K. The idea is to utilize the existing microchannel evaporator design approach -- which combines 20 micron width copper microchannels with a larger pore size low thermal conductivity "supply wick" in a flat form factor -- and apply that same design approach to a microchannel condenser. Based on axially-grooved heat pipe condenser heat transfer coefficients that are about twice those in the evaporator, and cylindrical two-phase loop evaporators that function very effectively as condensers when heat load sharing, proposed microchannel condenser is expected to achieve heat transfer coefficients equal to or greater than the previously mentioned water value. The technology should be highly effective with typical two-phase working fluids, and it can be integrated into a variety of two-phase heat transport systems, including ones that are capillary pumped, liquid mechanically pumped, or vapor compression pumped. The team that successfully carried out the previous SBIR program for the Navy is maintained: TA&T, ATK, B&K Engineering, and Aavid Thermalloy.