Ultra-Lightweight Compact Heat Exchangers for Aerospace Applications

Spacecraft environmental and thermal control systems make use of a variety of heat exchangers and condensers to provide clean water and maintain component temperatures at acceptable levels. In many cases these heat exchangers and condensers are fabricated using passivated stainless steel to retard corrosion and fouling processes, representing a significant weight penalty even for heat exchangers with minimal solid material. Leveraging extensive experience in the design and fabrication of ultra-compact heat exchangers, evaporators, and condensers using photochemically etched thin metal laminates, microVection has developed a concept for fabricating ultra-lightweight compact microfinned heat exchangers using 3-D printing technology. The concept involves 3-D printing a frame using relatively low-cost resins, followed by fully-dense plating of the frame to produce the desired heat exchanger feature dimensions. Heat exchanger fabrication is completed through heating in a furnace to remove the frame. The result is a heat exchanger that possesses all of the benefits of a laminated microfinned heat exchanger without the design constraints of continuous load paths through the structure. The proposed effort supports the NASA goal of reducing the mass and increasing the efficiency of heat acquisition components (per the 2015 NASA Technology Roadmap, TA 14.2.1 Heat Acquisition). Specific goals of the program are to design a heat exchanger with a performance metric below 0.4 kg/kW-K, eliminate the need for bonded/brazed joints, and demonstrate the ability to fabricate the concept.