An Advanced Columbus Thermal and Environmental Control System

摘要

Constraints of water cooling loop design concept realized in Columbus, a manned science laboratory on the International Space Station (ISS), impede flexible water loop temperature regulation and cabin air humidity control. These constraints, non-modeled system behavior, and changing environmental conditions require the adaption of operational products which generally involves cost- and time intensive follow-on analysis and developments. In this paper, enhancements for active condensate control and condensate storage are presented as a first step towards an integrated and station-wide humidity control concept accounting for more flexible heat exchanger inlet temperature regulation and automated and configurable condensation control. The advanced design is based upon the current pump-driven single water loop concept of the laboratory. Operationally gained temperature and humidity readings are presented to explain the interactions between the inlet fluid temperature of the cabin heat exchanger and the relative air humidity in varying environmental conditions. Conditions for a different condensing mode are defined based upon the analytical results. An inlet temperature range between 5 and 12.5 °C is suggested as an operational envelope to maintain a humidity range between 30 and 45%. It is mainly concluded that the enhancements will be a cost-effective solution and will create less operational efforts. Further analysis is still required to investigate in which conditions the heat exchanger can be operated in the no-condensing mode and if the operational envelope of 5 to 12.5°C is acceptable with the overall TCS functionality.