In response to the 2019 NASA SBIR solicitation topic Z2.01, “Spacecraft Thermal Management”, Advanced Cooling Technologies, Inc. proposes the development of a Variable Conductance Cold Plate to provide spatial and temporal isothermality over a 0.5 m2 area despite changes in heat load or inlet coolant temperature. The proposed design builds on ACT’s experience with passive two-phase devices, as well as our pumped two-phase expertise, to address the needs outlined in the subtopic titled, “Mechanically Pumped Two-Phase Flow Thermal Control System Technology Development”. In Phase I, ACT will design and demonstrate, through simulation and experiment, a prototype cold plate capable of managing heat fluxes up to 5 W/cm2 while maintaining spatial isothermality to within 3 K and temporal isothermality to within 0.05 K/min. This capability results from a passive design that exploits two-phase phenomena and the unique behavior of fluids at saturation conditions.
Compared to single-phase systems at significant heat loads, two-phase thermal management systems reduce spacecraft mass, volume, and power usage while providing performance improvements such as enhanced heat transfer and temperature uniformity. The Thermal Management Systems Roadmap (TA14) challenges researchers to develop two-phase thermal management systems that can manage high heat loads with improved temperature control. Such systems have been described by numerous NASA research papers and, as outlined there, these systems have significant mass- and power-saving potential, as well as additional capabilities such as isothermality and heat sharing. The purpose of the work proposed here is to support pumped two-phase thermal management system development by addressing technology gaps that are related to heat collection as identified in the referenced work and outlined in the solicitation.
The potential applications for the proposed cold plate are NASA missions that require spatial and temporal temperature control for improved instrumentation functionality. Additional applications for this cold plate and associated two-phase system would include spacecraft with thermal demands beyond the capabilities of capillary systems and those interested in low-cost alternatives to conventional thermal management systems.
In Phase II, ACT will extend the development of the cold plate to a complete two-phase thermal management system. During this phase, ACT will investigate application with the growing commercial satellite and spacecraft market. We currently provide passive thermal management solutions for this market and the proposed design would add to this product line.