An Efficient Air Evaporation Urine Processing System for Space Station

The inherent simplicity und reliability of air evaporation urine processing have been demonstrated in a number of system tests over the past 25 years. Although no flight-rated air evaporation systems have been built, the air evaporation approach has by far logged the most time in man-rated tests. Air evaporation offers additional inherent advantages such as near total water recovery and insentivity to intermittent operation. The principal disadvantage of simple-cycle air evaporator units built heretofore is their high energy requirement. An enhanced air evaporation configuration has been analyzed that incorporates a recuperator and an R12 heat pump for energy recovery. Performance is increased sufficiently to be competitive with alternative more complex processes. A parametric performance study was conducted in terms of major component efficiencies. Components were sized for an eight-man processing unit.