Pressure Controlled Heat Pipe Solar Receiver for Regolith Oxygen Production with Multiple Reactors

Abstract

Oxygen from lunar regolith can be extracted to provide breathable oxygen for consumption by astronauts during long term stays on the Moon. The regolith is heated using concentrated solar energy to 1050°C, and then hydrogen is introduced that reacts with the regolith, extracting oxygen in the form of water vapor. After several hours, the regolith is dumped, and fresh regolith is added. To minimize mass, it is desirable to supply thermal energy to multiple reactors with a single concentrator. Pressure Controlled Heat Pipes (PCHPs) can be used to transfer heat to the multiple reactors from a single heat source. During operation, one reactor is producing hydrogen at low solar power, while the other reactor is warming up a fresh batch of regolith. The PCHPs switch power between the two reactors as required. A high-temperature, demonstration system was designed, fabricated and tested using two PCHPs and two Constant Conductance Heat Pipes (CCHPs) to supply heat to two reactors. The system was fabricated with Haynes 230 as the envelope, sodium as the working fluid, and argon as the non-condensable gas. Tests demonstrated the use of PCHPs to switch power between two reactors as required, as well as provide a means to reject excess power. Nomenclature