Multi-VCHP (Variable Condenser Heat Pipe) Radiator

Advanced Cooling Technologies, Inc (ACT) will develop a high turndown ratio, freeze tolerant and passive Variable Heat Rejection Radiator for Planetary Surface and Space Habitats based on multiple Non-Integrated Hot Reservoir Variable Conductance Heat Pipes (HR-VCHPs). Habitat waste heat is acquired by a single-phase loop (SPL) using a benign fluid and further transferred to a series of these VCHPs charged with ammonia (or propylene depending on freezing and toxicity requirements) and argon (or neon, again, depending on the freezing requirements) that in turn transfer the heat (with self-adjusting resistance) to the radiators for ultimate rejection. In addition, the HR-VCHPs, that mainly consist of aluminum extrusions, will be flexible/deployable because of stainless steel bellows inserted as adiabatic sections that act as thermal barriers during survival. To develop the proposed system ACT will leverage concepts developed during several previous SBIR programs. One of them is the high reliability Non-Integrated HR-VCHP as the key component that was recently developed by ACT and successfully tested (both thermal control and reliability) on Peregrine 1 Lander in microgravity. This success elevated its TRL to 8. The primary Phase I objective is to demonstrate the feasibility of the concept by analysis, modeling, design and experimental validation. ACT will develop a four-HR-VCHP radiator prototype that will cool a single-phase pumped loop. One of the VCHPs will be flexible to demonstrate deployability. In addition, a preliminary design of a single-phase pumped loop to VCHP evaporator heat exchanger will be developed. The main objective in Phase II will be to demonstrate a full-scale Passive Non-integrated HR-VCHP Radiator system by designing, building and testing a full-scale proof of concept system elevating the TRL to 6. ACT will conduct a series of trade studies for different configurations potentially drifting away from the base-line design obtained in Phase I.