Project Title:

Space Suit Thermal Control Using Non-Toxic Microencapsulated Two-Phase PCM Fluid

12.01-2878
Space Suit Thermal Control Using Non-Toxic
	Microencapsulated Two-Phase PCM Fluid
Triangle Research and Development Corp.
PO Box 12696
Research Triangle Park, NC 27709
David P. Colvin  (919-467-2878)
JSC -- NAS9-17952

Abstract:

	 An investigation was conducted of a novel latent cooling fluid containing microencapsulated
phase change materials (PCMs) for spacesuit liquid cooling garments. The PCM slurry
could provide enhanced thermal properties and crew comfort as well as thermal control
simplicity. Emphasis was placed upon development of a PCM slurry coolant system with
a passive control strategy. 
	The Phase I results indicated the technical feasibility for the approach and suggested
specific criteria for its implementation. Both single-PCM slurries and multiple-PCM
mixtures exhibited novel and enhanced thermal properties exceeding those for water.
Fluid thermal capacitance exceeded by 50 times that of water while the heat transfer
coefficient was enhanced by over 100 percent. Latent heat transport within the microencapsulated
PCM slurry was also seen to provide practically isothermal thermal management across
the circulating fluid system. A non-toxic and non-flammable coolant with microencapsulated
PCMs should provide enhanced heat transport in a liquid-cooled garment and improve
astronaut comfort. Current designs of liquid-cooled garments use water with a sophisticated
active control system. A PCM coolant requires a simpler passive control strategy.

Potential Commercial Application:

Potential Commercial Application: Liquid-cooled garments can be used by fire fighters,
deep sea divers, Arctic workers, patients, and industrial and military personnel.