Innovative microgravity condenser for future fully closed Environmental Control and Life Support Systems

Nowadays space missions are designed to reach extremely high distances and consequently, the time spent on mission by manned space modules is constantly increasing. Therefore, there is the need to minimize, and if possible exclude, the possibility of refueling from the ground of materials of first necessity that are needed for the sustenance of life onboard (oxygen, water, food) in order to reduce the relative costs to new refueling-oriented space expeditions. The above is the reason why there is constant research in the aerospace field focused on the possibility of creating closed-loop systems, which would allow recycling air, water, and organic waste to obtain materials of first necessity usable by the crew. The Environmental Control and Life Support System (ECLSS) represents the fulcrum of the research regarding the realization of closed-cycle subsystems. The following dissertation was proposed by Center for Near Space (CNS), a non-profit organization founded in Italy in 2015 that has as its main mission the spread of usability of space by an increasing number of humans, in view to allow a different and more positive orientation of the public towards the astronautical activities in the outer terrestrial space. The object of the following research work is the study and design of the prototype of an innovative condensing heat exchanger (CHX) which must operate in microgravity and which would perform the function of recovering water directly from the air present in the environment inhabited, on board the space module, or from possible growth chambers of any plants that would produce food for the crew. Therefore, this component would be part of the closed cycle that could be realized in an ECLSS subsystem dedicated to water recovery. The final geometric configuration was designed to separate air and condensed water during the condensation process so as to keep the air always in contact with at least a part of the surfaces of the ducts through which the heat exchange takes place. The final objective is the design of a test bench with which it is possible to carry out some tests that allow to verify the operation of the CHX and confirm what has been explained above. Finally, the exact procedures to follow for the correct execution of the proposed tests have been described. The following work was carried out in collaboration with Thales Alenia Space (TAS). The requirements and constraints considered during the design phase are closely connected with the RUCOLA structure (Rack-like Unit for Consistent on-orbit Leafy crops Availability), a unit developed and tested in TAS's Recyclab laboratory in Turin. RUCOLA contains two parallel plant growth chambers, each of which has an independent subsystem for controlling temperature and relative humidity. The CHX, object of this thesis work, is designed to operate in RUCOLA's Air Management Subsystem, from which requirements and constraints for the design have been obtained.