MAINSTREAM ENGINEERING CORP SBIR Phase I Award, August 2022

Mainstream is partnering with Lockheed Martin Rotary and Mission Systems (LM RMS, letter of support attached) to mature our existing direct vapor compression (DVC) system for laser weapons systems (LWS) thermal management systems (TMS).  Historically, LWS TMSs have been composed of a 2-loop system; a pumped loop (either single- or two-phase) that collects heat from the LWS and a vapor compression loop that lifts the heat to reject to ambient.  The proposed DVC system eliminates the pumped loop entirely and directly cools the LWS with the vapor compression system.  Because the pumped loop is no longer necessary the single-loop DVC is at least 45% smaller, 33% lighter, and consumes 4% less peak input power than two-loop systems for a continuously operating LWS that needs tight temperature regulation (±2°C).  The addition of thermal energy storage (TES) and looser LWS temperature regulation has the potential to dramatically reduce the size, weight, and power (SWaP) of the DVC even more if the LWS is operated on a low duty cycle. Mainstream will work with LM RMS to determine coldplate heat loads/interfaces to improve the internal geometry and control valves of the existing DVC coldplate to accommodate higher heat fluxes, higher overall heat loads, and tighter temperature control anticipated for the 300-kW class FLA modules.