Thermoelectric integrated membrane evaporation system
AssigneeUnited Technologies Corporation
InventorRaymond B. Trusch
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Abstract
A urine-water recovery system is described which provides efficient potable water recovery from waste liquids. The design allows use over extended durations such as encountered in space flights. The system has advantages such as low power consumption, compactness, and gravity insensitive operation. The system comprises a vacuum distillation system combining a hollow fiber polysulfone membrane evaporator with a thermoelectric heat pump and condenser. With the system of the present invention, water purified from urine can be produced at a rate of more than 0.5 kg/hr at a total system energy of less than 400 w-hr/kg.
Claims7
A urine-water recovery system comprising:
- at least one thermoelectric heat pump having heating and cooling junction surfaces;
- at least one hollow fiber membrane evaporation tube having an interior and exterior surface;
- and at least one condensation surface;
- the heat junction surface being in fluid flow communication with the interior of the evaporation tube, the condensation surface being in fluid flow communication with the exterior surface of the evaporation tube, and the condensation surface being in heat transfer communication with the cooling junction surface, the heat transfer surface area of the junction surfaces matched with the interior surface area of the evaporation tubes to produce potable water at a total system energy use of less than about 1/3 of the latent heat of evaporation of the water, operation of the system being gravity insensitive and the heat transfer surface area of the junction surfaces matched with the interior surface area of the at least one evaporation tube to produce at least 0.5 kg/hr of potable water at a total system energy use of less than 400 w-hr/kg.
A process of recovering potable water from urinal waste comprising:
- heating the urinal waste to pasteurization temperature by contact with the hot junction surface of at least one thermoelectric heat pump;
- passing said heated waste through the interior of at least one hollow fiber membrane and evaporating steam from the exterior of said membrane by subjecting the exterior of the membranes to a vacuum;
- followed by condensing said steam by contact with a condensation surface in heat transfer communication with the cold junction surface of the thermoelectric heat pump;
- the surface area of the hot and cold junction surfaces of the heat pump matched with the interior surface area of the hollow fiber membrane to produce potable water at a total system energy use of less than about 1/3 of the latent heat of evaporation of the water, operation of the system being gravity insensitive.
Dependencies are inferred from the claim text.