NASA is seeking an advanced heater to replace the current heaters used in the carbon dioxide removal assemblies. The current SOTA spacecraft sorption system utilizes commercial off-the-shelf (COTS) resistive heaters coupled with conductive fins. These current heaters were not manufactured for use on spacecraft, and as such, are sub-optimal, particularly for planned deep space missions. These deep space missions will be power limited and therefore require a more efficient method of sorbent regeneration. To address this need, Mainstream proposes a method of embedding a heating element directly into the sorbent structure. This method will drastically reduce thermal contact resistance, reducing regeneration cycle time and total power input. In Phase I, Mainstream will formulate a zeolite paste capable of being 3D printed into a self-supporting structure, develop the process of embedding the heating elements into the structures, and demonstrate the fabrication of a zeolite structure with embedded heating elements. These tasks will lead to the ultimate goal of printing fully functional replacement sorbent beds with embedded heating elements for existing and planned spacecraft during the Phase II.
This proposal aims to improve on SOTA via structured packing of the sorption bed using AM to embed heating elements. For NASA, the ability to 3D print adsorbent and catalysts beds that include embedded heating/cooling elements will make an immediate impact in a variety of applications. The reduction in cost and SWAP provided by the upgraded systems will allow for further systems to be incorporated so that waste gas no longer needs to be vented overboard and chemical looping can be utilized.
Packed beds with embedded heating elements will offer large efficiency gains over traditionally packed beds as structures can be fully optimized for heat and mass transfer. Applications in extremely critical and high value markets including catalytic convertors, chemical and toxic industrial scrubbers, pharmaceutical production, fuel cells, and breathing apparatuses could see large improvements.