Reduced Gravity Direct Contact Heat Exchanger for Cabin Air Dehumidification

The Interphase Transport Phenomena laboratory (ITP) at Texas A&M University (TAMU) has developed and tested a microgravity dehumidification system. This system utilized the Microgravity Vortex Separator (MVS) developed at TAMU to significantly reduce humidity levels in air, separate and accumulate the water removed from the air, and reduce air temperature through direct contact heat exchange. This device operates by producing and managing fluid vortices within a cylindrical separation volume. For the Vortex Dehumidification System (VDS) separator, a liquid vortex provides a replacement for gravitational acceleration in the form of centrifugal acceleration. Warm and humid air passes through cold water. Thermal energy is rapidly exchanged between the two phases, lowering the air temperature to that of the water and removing water vapor present in the air through condensation. This condensate is separated to the liquid layer and either accumulated or removed and recycled. Testing of this concept was conducted both in the laboratory facilities at TAMU and aboard a reduced gravity aircraft. For air with an inlet temperature of 23.3 degrees Fahrenheit with an absolute humidity of 22.5 g/m³, 0.02 g/s of water vapor was condensed from a constant air flow rate of 25 SLPM while maintaining complete phase separation during microgravity periods. Moreover, TAMU has tested MVS designs with volumes in excess of 2 L that are capable of processing hundreds of SLPM of gas flow with no loss of separation performance.