Condensing Heat Exchangers as Main Components in LSS for Manned Spaceflight

Condensing heat exchangers are used for the thermal and humidity control within spaceflight LSS. Heat loads are transferred to a coolant loop, and humidity is removed by condensation and separation from the air flow.

For minimum mass and volume at a maximum of effectiveness, adaptable plate-fin configurations are superior. Efficient separation of the condensate under zero-g conditions is achieved by enhancement of wettability of condenser surfaces with a hydrophilic coating, and the drain-off through a so-called slurper section.

Exemplary, the Hermes ECLSS condensing heat exchanger and the EVA sublimator unit are presented. The advanced design comprises a new type of hydrophilic coating and several constructional details, resulting in a significant mass reduction.