HIGH EFFICIENCY HEAT PUMP INDUSTRIAL DRYING WITH WATER VAPOR-SELECTIVE MEMBRANES

A method of drying, including the steps of loading a mass to be dried into a drying volume, circulating air from the drying volume into a first membrane module, circulating moist air from the first membrane module to a second membrane module and circulating dried air from the first membrane module to a condenser, circulating moist air from the second membrane module to an evaporator, draining condensate from the evaporator, circulating moist air from the condenser to the evaporator, circulating heated dry air from the evaporator to the condenser, and circulating heated dry air from the condenser to the drying volume. Each respective membrane module defines an enclosure bisected by water permeable membrane for extracting water from moist air circulated therethrough. A method of passive dehumidification using hollow fiber membranes, including a quasi-counter flow effectiveness model, a partial pressure-driven ε-NTU method for mass transfer, sensitivity analysis comparing module geometries and membrane properties, optimized form factors, and scalability design guidelines. A method of active dehumidification in the form of dual-module humidity pump, including two membranes to restrict pressure ratio, a variable-speed water vapor compressor, a variable-speed vacuum pump, three-way valves for reversed air flow, and a backwash mode operation for membrane fouling prevention.