Energy-efficient conductive-gap membrane distillation

An apparatus for energy-efficient conductive-gap distillation comprising:

• a feed-liquid source including a feed liquid;
• a distillation module comprising:
• a) a first feed-liquid chamber in fluid communication with the feed-liquid source, the first feed-liquid chamber including a heat-transfer wall;
• b) a conduit coupled with the first feed-liquid chamber to extract the feed liquid after the feed liquid flows through the first feed-liquid chamber;
• c) a heat source configured to heat the feed liquid in the conduit;
• d) a conductive-gap chamber filled with liquid and adjacent the heat-transfer wall;
• e) a second feed-liquid chamber coupled with the conduit and configured to receive the feed liquid after the feed liquid flows through the conduit and is heated by the heat source, wherein the second feed-liquid chamber includes a selectively porous material that allows a component of the feed liquid to pass through the selectively porous material and exit the second feed-liquid chamber in vapor form but not in liquid form, wherein one side of the selectively porous material faces a surface of the heat-transfer wall of the first feed-liquid chamber across the conductive-gap chamber in a configuration that allows the vapor to condense into the liquid in the conductive-gap chamber such that the liquid then conducts condensation energy through the heat-transfer wall into the first liquid chamber, and wherein the selectively porous material has an overall thermal conductance of less than 500 W/m2·K;
• and
• f) thermally conductive fins extending from the heat-transfer wall across the conductive-gap chamber and supporting the selectively porous material from collapsing onto the heat-transfer wall while leaving passages for flow of the liquid condensate through the conductive-gap chamber;
• and
• a condensate collection receptacle in fluid communication with a gap between the selectively porous material and the heat-transfer wall.

A method for energy-efficient liquid gap distillation, comprising:

• flowing a feed liquid through a first feed-liquid chamber of a distillation module, wherein the first-feed liquid chamber includes a heat-transfer wall;
• heating the feed liquid;
• flowing the heated feed liquid through a second feed-liquid chamber of the distillation module, wherein the second feed-liquid chamber includes a selectively porous material that includes an outer surface in fluid communication with a gap between the selectively porous material and the first feed-liquid chamber, wherein the selectively porous material has an overall thermal conductance of less than 500 W/m2·K;
• transferring heat from the feed liquid in the second feed-liquid chamber through thermally conductive fins extending from the heat-transfer wall across the conductive-gap chamber and supporting the selectively porous material from collapsing into the heat-transfer wall;
• permeating a vapor component from the feed liquid in the second feed-liquid chamber through the selectively porous material into the conductive-gap chamber;
• condensing the vapor component of the feed liquid to form a liquid condensate that fills the conductive-gap chamber;
• removing the liquid condensate from the conductive-gap chamber;
• and
• removing from the second feed-liquid chamber a brine remaining from the feed liquid after the vapor component permeates through the selectively porous material.

A method of high-effectiveness heat transfer between two fluids while also producing additional pure water from the hot feed liquid comprising:

• flowing a cool fluid through a coolant-flow chamber of a distillation module, wherein the coolant-flow chamber includes a heat-transfer wall;
• flowing a hot feed liquid through a hot-feed-liquid chamber of the distillation module, wherein the hot feed liquid has a higher temperature than the cool fluid, and wherein the hot-feed-liquid chamber includes a selectively porous material that includes an outer surface in fluid communication with a conductive-gap chamber between the selectively porous material and the coolant-flow chamber, wherein the selectively porous material has an overall thermal conductance of less than 500 W/m2·K;
• transferring heat from the feed liquid in the hot-feed-liquid chamber through thermally conductive fins extending from the heat-transfer wall across the conductive-gap chamber and supporting the selectively porous material from collapsing onto the heat-transfer wall;
• permeating a vapor component from the hot feed liquid in the hot-feed-liquid chamber through the selectively porous material into the conductive-gap chamber;
• condensing the vapor component of the hot feed liquid to form a liquid condensate that fills the conductive-gap chamber;
• removing the liquid condensate from the conductive-gap chamber;
• and
• removing, from the hot-feed-liquid chamber, a cooler brine remaining from the hot feed liquid after the vapor component permeates through the selectively porous material;
• and
• removing the cool fluid as a warmer stream from the coolant-flow chamber after energy is transferred into the cool fluid from the conductive-gap chamber.