3) may include, as illustrative examples, certain molecular sieves (as one example, SAPO-34 a micropore zeolite, CAS No. 1318 Feb. 1) and certain zeolites having the properties described above. Any combinations of the MOF(s) described herein, or other MOF9s), or other compositions capable of water adsorption and water desorption may also be used alone or in various combinations.

In particular embodiments, the water capture material (3) can be disposed on one or more structural element(s) (17) located inside of one or a plurality of water capture modules (6) (depicted in the example of FIG. 3 as parallel diagonal lines). The structural element(s) (17) can be configured to increase the surface area of the water capture material (3) exposed to the supply air (2) to enhance water (1) adsorption from the supply air (2) during the adsorption mode (AM) of the water harvester (5) or enhance heat transfer to the water capture material (3) during the desorption mode (DM) of the water harvester (5). In particular embodiments, the structural element(s) (17) can include plates or fins which can be independently coated on one or both sides with the water capture material (3). In some variations, the plates or fins can be arranged in spatial relationship, and in particular embodiments arranged substantially parallel to each other, with a gap existing between adjacent plates or fins. In particular embodiments, the gap between adjacent plates relative to the length of each plate can be adjusted to achieve contact with the supply air (2) to maximize water (1) adsorption by the water capture material (3) during the adsorption mode (AM) and water (1) desorption during the desorption mode (DM). In some variations, the gap between adjacent plates or fins can be about one percent (1%) to about five (5%) of the length of a plate or fin. In particular embodiments, the plates or fins can be coated with layers of the water capture material (3) each having a thickness between about 10 microns to about 500 microns, or between about 50 microns to 500 microns, or between about 10 microns to about 50 microns. In particular embodiments, layers of water capture material (3) in these thickness ranges can allow for faster adsorption and/or desorption as compared to thicker layers of water capture material (3). In other embodiments, the plates or fins can be coated with layers of the water capture material (3) each having a thickness of about 0.1 centimeter (“cm”) to about 1 cm. Thickness in this range may allow for production of larger quantities of water vapor (11) during the desorption mode (DM) as compared to thinner layers. In certain embodiments, each layer of the water capture material (3) on the plates or fins can have a porosity. In some variations, the calculated porosity (the volume of the pores in the water capture material divided by the total volume of the water capture material×100) can be at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 80%; or about 40% to about 90%, about 50% to about 90%, about 40% to about 80%, about 50% to about 80%, or about 60% to about 80%. In other embodiments, the layer of the water capture material (3) can be substantially non-porous. In particular embodiments, the thickness of the layer of the water capture material (3) can be greater than the thickness of a plate for fin. In certain embodiments, only one side of the plate of fin may be coated with water capture material (3) with the thickness of the water capture material relative to the thickness of the plate of fin adapted to reduce or minimize the amount of energy used per unit of water released from the water capture material (3) during the desorption mode (DM) of the water harvester (3). Similarly, in certain embodiments, both sides of the plate or fin can be coated with the water capture material (3) and the ratio of the thickness of the first layer (e.g., first side layer) of the water capture material (3) to the thickness of the plate or fin to the thickness of the second layer (e.g., second side layer) of the water capture material (3) can be adapted to reduce or minimize the amount of energy used per unit of water (1) released from the water capture material (3) during the desorption mode (DM) of the water harvester (5). The plates or fins may be made of any suitable material, including any suitable metal or plastic. As an illustrative example, the plates can comprise one or more of aluminum, copper, iron, nickel, tungsten. In some variations, the plates comprise a solid metal. In other variations, each plate or fin can have a cellular design defining small channels or corrugates. In other variations, each plate or fin can further include topographic features that enhance water adsorption. Illustrative examples of topographical features include one or more of: granulation, perforations, arc holes, bumps, ridges, or grooves, or any combination thereof. In another variation, the plates or fins can comprise a mesh.

Again, with primary reference to FIGS. 3 through 5, in the adsorption mode (AM) of the water harvester (5), the water capture material (3) absorbs water (1) from a supply air (2) passing through one or more of the plurality of water capture modules (6). In particular embodiments, one or more air circulators (18) can operate to move the supply air (2) over the water capture material (3) contained in one or more of the plurality of water capture modules (6) to assist adsorption of water (1) by the water capture material (3). In particular embodiments, the air circulator (18) can move the supply air (2) at determined velocity through the water capture material (3). As an illustrative example, the water capture material (3) can be coated on adjacent structural elements (17), and the supply air (2) can pass through gaps between the structural elements (17) during the adsorption mode (AM). The adsorption mode (AM) as to one or more of the plurality of the water capture modules (6) can conclude when the water capture material (3) reaches a target level of water saturation or a target rate of water adsorption. In particular embodiments, the adsorption mode (AM) as to one or more of the plurality of water capture modules (6) can conclude which the discharge air (4) from one or more of the plurality of modules (3) reaches or exceeds a target level of relative humidity (RH) or a target level dew point (DP). In other embodiments, the adsorption mode (AM) as to one or more of the plurality of water capture modules (6) can conclude based on elapse of a period time. For example, as to one or more of the plurality of water capture modules (6) the water harvester (5) can switch from the adsorption mode (AM) to the desorption mode (DM) after elapse of a pre-determined period of time. Understandably, various combinations of these events can be utilized to conclude the adsorption mode (AM) of one or more of the plurality of water capture modules (6).

Again, with primary reference to FIG. 3, the first chamber (9) can be thermally coupled to a heating source (10). The term “thermally coupled” broadly encompasses any mode of heat transfer to the first chamber (9) and can include one or more of conduction, convection, or radiation to heat the inside of the first chamber (9). The heating source (10) can comprise any mechanism, object, area, material, composition, byproduct, waste energy, or energy, and combinations thereof, which can transfer heat to or into the first chamber (9). In the illustrative example of FIG. 3, the heating source (10) resides inside of the first chamber (9), however, the heating source (10) can be disposed outside of the first chamber (9) and adapted to or configured to directly heat the structure of first chamber (9), or the heating source (10) can be disposed outside of the first chamber (9) and adapted to or configured to direct heated air (19) into the first chamber (9).

In the desorption mode (DM), the first chamber (9) can be fluidically coupled by an airflow path (20) (depicted in the example of FIG. 3 as a broken line with arrows pointing in the direction of airflow) to one or more of said plurality of water capture modules (6). The recirculated airflow (13) heated in the first chamber (9) recirculates in the airflow path (20) to heat the water capture material (3) contained in one or more of the plurality of water capture modules (6) fluidically coupled to the first chamber (9) to desorb water vapor (11) from the water capture material (3). Typically, the heating source (10) operates to heat the recirculated airflow (13) between the first chamber (9) and the one or more of the plurality of water capture modules (6) in the desorption mode (DM) to one or more temperatures in the range of about 80° C. (about 176° F.) to about 160° C. (about 320° F.). Specific temperatures within the temperature range can be dependent upon the water capture material(s) (3), or combinations of water capture materials (3), contained in the one or more of the plurality of water capture modules (6). However, this illustrative example is not intended to preclude embodiments which exploit temperatures outside the range to release water vapor (11) from the water capture material (3).

Again, with primary reference to FIG. 3, the heating source (10) can comprise or consist of a first heat exchanger (21) through which heated fluid (22) circulates. In particular embodiments, the first heat exchanger (21) can be disposed in the first chamber (9). The first heat exchanger (21) can be configured to transfer heat from the heated fluid (22) to the recirculated airflow (13) between the first chamber (9) and one or more of the plurality of water capture modules (6) in the desorption mode (DM). In particular embodiments, the heating source (10) can comprise a heat pump (23). A heat pump (23) can include one or more of: a compressor (24), an expansion valve (25), a condenser (26) (or hot-side heat exchanger), and an evaporator (27) (or cold-side heat exchanger). The compressor (24) can operate to compress a refrigerant resulting in a heated fluid (22) which can be circulated to the condenser (26). The condenser (26) can transfer heat to the first chamber (9) sufficient to release water vapor (11) from the water capture material (3) contained in one or more of the plurality of water capture modules (6) in the desorption mode (DM) of the water harvester (5). The condenser (26) (hot side of the heat exchanger) can be set to operate at one or more temperatures in the range of about 90° C. (about 194° F.) to about 160° C. (about 320° F.). In particular embodiments, the water vapor (11) desorbed from the water capture material (3) of the plurality of water capture modules (3) in the desorption mode (DM) can be released to the atmosphere.

Again, with primary reference to FIG. 3, embodiments of the water harvester (5) can include a second chamber (12) fluidically coupled to the first chamber (9). The water vapor (11) released from the water capture material (3) during the desorption mode (DM) can be carried in the recirculated airflow (13) in the airflow path (20) from the first chamber (9) to the second chamber (12) during the condensation mode (CM) of the water harvester (5). In particular variations, the desorption mode (DM) can operate independent of the condensation mode (CM) until reaching a target water vapor (11) concentration in the first chamber (9). The air circulator (18) can then operate to generate the recirculated airflow (13) between the first chamber (9) and the second chamber (12) of the water harvester (5). Recirculated airflow (13) between the first chamber (9) and the second chamber (12) can initiate the condensation mode (CM) of the water harvester (5). In particular embodiments, the adsorption mode (AM) as to one or more of the plurality of water capture modules (6) (M1 . . . M4), the desorption mode (DM) as one or more of the plurality of water capture modules (6) (M1 . . . M4), and the condensation mode (CM) can operate as independent events. In particular embodiments, the adsorption mode (AM) as to one or more of the plurality of water capture modules (6) (M1 . . . M4), the desorption mode (DM) as one or more of the plurality of water capture modules (6) (M1 . . . M4), and the condensation mode (CM) can operate concurrently, or in combinations of independent and concurrent events depending on the application.

Again, with primary reference to FIG. 3, a cooling source (14) can be thermally coupled to the second chamber (12). The cooling source (14) can operate to cool the water vapor (11) carried in the recirculated airflow (13) between said first chamber (9) and the second chamber (12) during the condensation mode (CM) of the water harvester (5). The cooling source (14) can sufficiently cool the water vapor (11) in or passing through the second chamber (12) to cause condensation of at least a portion of the water vapor (11) carried by the recirculated airflow (13) into liquid water (15). In particular embodiments, the cooling source (14) can be disposed to cool the structure of the second chamber (12) to a temperature lower than the dewpoint of the recirculated airflow (13) within the second chamber (12) to cause condensation of at least a portion of the water vapor (11) carried by the recirculated airflow (13) into liquid water (15). The second chamber (12) can be configured to increase the surface area of the internal surfaces of the second chamber (12) to increase condensation of water vapor (11) in the recirculated airflow (13) within the second chamber (12). In other embodiments, the cooling source (14) can be disposed inside of the second chamber (12) and the recirculated airflow (13) carrying water vapor (11) can pass over the cooling source (14) to cause condensation of at least a portion of the water vapor (11) within the second chamber (12) into liquid water (15). In particular embodiments, the cooling source (14) can comprise cooled air (28) produced by a machine or other process discrete from the water harvester (5) directed proximate to or into the second chamber (12). As an illustrative example, waste cold can be generated from the re-gasification of liquid natural gas from the frozen state. In other embodiments, the cooling source (14) can comprise a second heat exchanger (29) through which a cooled fluid (30) circulates. The second heat exchanger (29) can be disposed proximate to or inside the second chamber (12) to cool the recirculated airflow (13) carrying the water vapor (11) contained in or passing through the second chamber (12). The recirculated airflow (13) can be cooled to below the dewpoint to cause condensation of at least a portion of the water vapor (11) into liquid water (15). The liquid water (15) can be collected in a water collection reservoir (16). In particular embodiments, the liquid water (15) can be used as drinking water. In other particular embodiments, the liquid water (15) can be used for direct evaporative cooling (DEC) (31). In embodiments utilizing DEC (31), a water pump (32) can be connected to the collection reservoir (16). The water pump (32) can be configured to transfer liquid water (15) from the collection reservoir (16) to a sprayer (33) positioned in proximity to an indoor airflow inlet (34) of an indoor space (35). The sprayer (33) can operate to spray liquid water (15) into the indoor airflow (36) to further lower temperature and/or raise the RH and AH of the indoor airflow (36) passing into the indoor space (35).

Again, with primary reference to FIG. 3, in particular embodiments, the cooling source (14) can be an evaporator (27) of a heat pump (23). An expansion valve (25) can be configured to receive the heated fluid (22) from the condenser (26). The expansion valve (25) can operate to allow expansion of the heated fluid (22) to produce a cooled fluid (30). The cooled fluid (30) can circulate to the evaporator (27). The evaporator (27) (cold-side heat exchanger) can be set to operate at temperatures in the range of about 30° C. (about 86° F.) to about 95° C. (about 203° F.). The evaporator (27) can be associated with the second chamber (12) to transfer heat, whether directly or indirectly, from the recirculated airflow (13) carrying water vapor (11) contained in or passing through the second chamber (12). As illustrative examples, the evaporator (27) can be disposed to transfer heat from one or more of: the structure of the second chamber (12), from structural elements within the second chamber (12), from the recirculated airflow (13) within the second chamber (12), or otherwise disposed to cause a decrease in temperature of the recirculated airflow (13) sufficient to cause condensation of at least a portion of the water vapor (11) carried by the recirculated airflow (13) in the condensation mode (CM) of the water harvester (5).

Now, with primary reference to FIGS. 3 through 5, embodiments of the water harvester (5) can include a reconfigurable airflow path (37) interconnecting the plurality of water capture modules (6). The reconfigurable airflow path (37) allows one or more of the plurality of modules (6) to be fluidically coupled to the first chamber (9) during the desorption mode (DM) of the air water harvester (5) while one or more of the plurality of modules (6) remain fluidically coupled, connected or interconnected to the supply air (2) to independently or concurrently operate in the adsorption mode (AM) of the water harvester (5).

In particular embodiments, each of the plurality of water capture modules (6) can be fluidically coupled to an adsorption airflow inlet (38) and an adsorption airflow outlet (9), wherein the adsorption airflow inlet (38) and the adsorption airflow outlet (39) remain open to allow the supply air (2) to pass into one or more of the plurality of water capture modules (6) and to allow the discharge air (4) to egress from one or more of the water capture modules (6) during the adsorption mode (AM). In particular embodiments, the plurality of water capture modules (6) in the adsorption mode (AM) can be coupled by the reconfigurable airflow path (37) to concurrently in parallel receive the supply air (2). In particular embodiments, the plurality of water capture modules (6) in the adsorption mode (AM) can be coupled by the reconfigurable airflow path (37) in series (as shown in the illustrative example of FIGS. 4 and 5). During operation of a plurality of water modules (6) fluidically coupled in series, the reconfigurable airflow path (37) can be configured to circulate the supply air (2) to the adsorption airflow inlet (38) of a first in the series of a plurality of water capture modules (6) containing water capture material (3) having greatest water saturation (shown in the example of FIG. 4 as module M5) with the discharge air (4) egressing from the adsorption airflow outlet (39) of the first in the series of a plurality water capture modules (6) into the adsorption air inlet (38) of the second in the series of a plurality of water capture modules (6) (shown in the example of FIG. 4 as module M6), and repeated through the series of the plurality of water capture modules (6), whereby the supply air (2) passes to a last in the series of the plurality of water capture modules (6) containing water capture material (3) having least water saturation (shown in the example of FIG. 4 as module M1). The discharge airflow (4) egresses from the adsorption airflow outlet (39) of the last in the series of the plurality of water capture modules (6).

Again, with primary reference to FIGS. 3 thorough 5, each of the one or more of plurality of water capture modules (6) include a desorption airflow inlet (40) and a desorption airflow outlet (41). In the adsorption mode (AM), the adsorption airflow inlet (40) and the adsorption airflow outlet (412) remain open to allow supply air (2) to flow though the corresponding water capture module (6), while the desorption airflow inlet (40) and a desorption airflow outlet (41) remain closed. In the desorption mode (DM), the desorption airflow inlet (40) and the desorption airflow outlet (41) remain open to allow recirculated airflow (13) from the first chamber (9) to pass through the water capture material (3) of the corresponding water capture module (6) while the adsorption airflow inlet (38) and the adsorption airflow outlet (39) remain closed.

Now, with primary reference to FIGS. 3 and 4, the reconfigurable airflow path (37) can dispose one or more of the plurality of water capture modules (6) in the desorption mode (DM) (shown in FIGS. 3 and 4 as module M3) in which the adsorption airflow inlet (38) and the adsorption airflow outlet (39) remain closed and the desorption airflow inlet (40) and the desorption airflow outlet (41) remain open to fluidically couple one of the plurality of modules (6) (shown in FIGS. 3 and 4 as module M3) to the first chamber (9). The reconfigurable airflow path (20) can concurrently fluidically couple one or more of the plurality of water capture modules (6) (shown in FIG. 3 as module M1 and shown in FIG. 4 in serial order modules M5 through Mn and M1) to receive the supply airflow (2) in series to concurrently operate in the adsorption mode (AM) while one or more of the plurality of water capture modules (6) (shown in FIG. 4 as M3) operates in the desorption mode (DM).

Again, with primary reference to FIGS. 3 and 4, in particular embodiments of the water harvester (5), the plurality of water capture modules (6) can be fluidically coupled, connected or interconnected by a plurality of conduits and valves (also identified as one of V1 . . . V15) (also referred to as a “valved conduit”) (VC). In the illustrative examples, each of the plurality of water capture modules (6) can be fluidically coupled to a valved adsorption airflow inlet (38) (V1) and a valved adsorption airflow outlet (39) (V2). The valved adsorption airflow inlet (38) (V1) and a valved adsorption airflow outlet (39) (V2) remain open in the adsorption mode (AM) of the plurality of water capture modules (6). In particular variations, in which the water harvester (5) operates a desorption mode (DM), or further includes the condensation mode (CM), each of the plurality of water capture modules (6) can be fluidically coupled to a valved desorption airflow inlet (40) (V3) and a valved desorption airflow outlet (41) (V4), wherein the valved desorption airflow inlet (40) (V3) and the valved desorption airflow outlet (41) (V4) remain open, and wherein the valved adsorption airflow inlet (38) (V1) and the valved adsorption airflow outlet (39) (V2) remain closed during the desorption mode (DM). The valved conduit (VC) can further provide a valved supply conduit (VSC) having a valved supply branch (42) (V5) to each valved adsorption airflow inlet (38) (V1). The valved conduit (VC) can further provide a valved discharge conduit (VDC) having a valved discharge branch (43) (V6) from each valved adsorption airflow outlet (39) (V2). The valved conduit (VC) can further include a valved lateral branch (44) (V7) interconnecting a valved discharge branch (43) (V6) of a first of a plurality of water capture modules (6) to a valved supply branch (42) (V5) of a second of a plurality of modules (6).

Now, with primary reference to the illustrative example of FIGS. 4 and 5, in particular embodiments once the desorption mode (DM) concludes for one or more of the plurality of water capture modules (6), the reconfigurable airflow path (37) can switch one or more of the plurality of water capture modules (6) of the water harvester (5) from the desorption mode (DM) directly to the adsorption mode (AM) or in particular embodiments from the desorption mode (DM) to the adsorption mode (AM) after an intermediate step of cooling the water capture module (6) in post cool mode (PCM). Similarly, the reconfigurable airflow path (37) can switch one or more of the plurality of water capture modules (6) of the water harvester (5) from the adsorption mode (AM) directly to the desorption mode (DM), or in particular embodiments, to the desorption mode (DM) after an intermediate step of preheating the water capture module (6) in a preheat mode (PHM). The illustrative example of FIGS. 3 and 4, show that upon conclusion of the desorption mode (DM) of water capture module (6) (M3), the reconfigurable airflow path (37) switches water capture module (6) (M3) from the desorption mode (DM) to a post-cool mode (PCM) and switches water capture module (6) (M4) from a pre-heat mode (PHM) to the desorption mode (DM).

Now, with primary reference to FIGS. 3 through 5, in particular embodiments, the reconfigurable airflow path (37) can be extended from a desorption airflow inlet (40) and desorption airflow outlet (41) of a water capture module (6) to an external heat exchanger (45) (a shown in FIG. 1). In particular embodiments, the desorption airflow inlet (40) and desorption airflow outlet (41) of one or more of the plurality of water capture modules (6) can be coupled to the external heat exchanger (45) to generate an external exchanger airflow (E to D) through the one or more water capture modules (6) to cool the water capture module (6) in the post cool mode (PCM) after completion of the desorption mode (DM) and prior to initiation of the adsorption mode (AM). In particular embodiments, the desorption airflow inlet (40) and desorption airflow outlet (41) of one or more of the plurality of water capture modules (6) can be coupled to the external heat exchanger (45) to generate an airflow through the water capture module (6) (B to C) to preheat the water capture module (6) in the preheat mode (PHM) after completion of the adsorption mode (AM) and prior to initiation of the desorption mode (DM).

In particular embodiments, the cooler airflow from a water capture module (6) in the preheat mode (PHM) (in the example of FIG. 1 module M4) can pass through the external heat exchanger (4) from inlet port B to outlet port C and the hotter airflow from a water capture module (6) in post cool mode (PCM) can pass through the external heat exchanger (45) from port E to port D. The airflow passing from inlet port C to outlet port B can increase in temperature and be returned to the water capture module (6) in the preheat mode (PHM) (in the example of FIG. 1 module M4) to correspondingly raise the temperature of the water capture module (6) in the preheat mode (PHM). Conversely, the airflow passing from inlet port E to outlet port D of the external heat exchanger (45) can lower the temperature and be returned the water capture module (6) in the post cool mode (PCM) (in the example of FIG. 1 module M2) to correspondingly lower the temperature of the water capture module (6) in the post cool mode (PCM). Concurrently, one or more water capture modules (6) can be the desorption mode (DM) (in the example of FIGS. 3 and 4 module M3).

Now, with primary reference to FIG. 4, as to each of the valved desorption airflow inlet (40) (V3) and the valved desorption airflow outlet (41) (V4), the reconfigurable airflow path (37) can be respectively fluidically coupled to a pair of valves (V8 and V9) and (V10 and V11). Each one of valves V8 and V10 can be respectively fluidically coupled to another pair of valves (V12 and V13) and (V14 and V15). Each of valves V3, V4, V8, V9, V10, V11, V12, V13, V14, and V15 can be switched from a closed condition to an open condition to alter the flow path to each of a plurality of water capture modules (6) to operate in one of: the adsorption mode (AM), the post cool mode (PCM) the preheat mode (PHM) or the desorption mode (DM). As one illustrative example, in the post cool mode (PCM) (in the example of FIG. 4 water capture module M2), V3, V8 and V13 remain open to create a flow path between V3 and port D of the external heat exchanger (45) and V4, V10, and V15 remain open to create a flow path between V4 and port E of the external heat exchanger (45), wherein water capture module (6) (M2) delivers hotter air to port E of the external heat exchanger (45) and receives cooler air from port D of the external heat exchanger (45), thereby cooling water capture module (6) (M2) prior to be switched to the adsorption mode (AM). Remaining valves V9, V11, V12, and V14 remain closed.

As another illustrative example, in the preheat mode (PHM) of a water capture module (6) (in the example of FIG. 4 water capture module M4), V3, V8 and V12 remain open to create a flow path between V3 and port C of the external heat exchanger (45) and V4, V10, and V14 remain open to create a flow path between V4 and port B of the external heat exchanger (45), wherein water capture module (6) (M4) delivers cooler air to port C of the external heat exchanger (45) and receives hotter air from port B of the external heat exchanger (45), thereby preheating the water capture module (6) (M4) prior to be switched to the desorption mode (DM). Remaining valves V9, V11, V13 and V15 remain closed.

As another illustrative example, in the desorption mode (DM) (in the example of FIG. 4 module M3) V3, V9 remain open to create a flow path to the first chamber (9) and V4 and V11 remain open to create a flow path from the first chamber (9). Remaining valves V10, V12, V13, V14 and V15 remain closed.

As an illustrative example of the advantage of particular embodiments of the invention described above, in the instance in which the water capture material (3) comprises a MOF and the adsorption of water (1) from the supply air occurs at 20° C. (68° F.) and the desorption of water vapor (11) from the MOF occurs at 80° C. (176° F.), then the water capture module (6) containing the water capture material (3) must be heated from 20° C. (68° F.) to 80° C. (176° F.) to yield water vapor (11). The energy needed to raise the temperature of the water capture module from 20° C. (68° F.) to 80° C. (176° F.) can be obtained in whole or in part at no cost by using an embodiment of the external heat exchanger (45), as described above, to concurrently cool down a water capture module (3) in the post-cool mode (PCM) from 80° C. (176° F.) toward 20° C. (68° F.) and concurrently pre-heat a water capture module (3) in the preheat mode (PHM) from 20° C. (68° F.) toward 80° C. (176° F.). The equilibrium temperature X value between the water capture module in the post-cool mode (PCM) and the water capture module (3) in the pre-heat mode (PHM) will depend on the efficiency of the external heat exchanger (45) and the water capacity in both water capture module in the pre-heat mode (PHM) and the water capture module (3) in the post-cool mode (PCM).

As another illustrative advantage of particular embodiments of the invention described above, in the instance in which the water capture material (3) comprises a MOF-303 and the desorption mode (DM) occurs at 80° C. (176° F.), the at the end of the desorption mode (DM) the air in the desorption chamber (9) (first chamber) at 80° C. (176° F.) will have a RH of 18% corresponding to an AH of 56.75 g of water per kg of dry air. If the water capture module (3) transitions directly from the desorption mode (DM) to the adsorption mode (AM), the water vapor contained in the water capture module (3) is released back into the dehumidified airflow. However, if the water capture module (3) at the conclusion of the desorption mode (DM) transitions to the post-cool mode (PCM) the MOF-303 and the air about the MOF-303 can be cooled to a lower temperature of 40° C. (104° F.) forcing re-adsorption of the water (1) that was released during the desorption mode (DM) but not condensed back into the water capture module (3) and re-adsorbed by the MOF-303. As a result, the AH value of the air in the water capture module (3) in the post cool mode (PCM) can be only 6.6 g/kg of dry air at 40° C. (104° F.) and 15% RH. Thus, a considerably smaller amount of water (1) passes into the dehumidified airflow.

Now, with primary reference to FIG. 3, particular embodiments can further include a discharge heat exchanger (46) fluidically coupled to the adsorption airflow outlet (39) of one or more of the plurality of water capture modules (6) to receive the discharge air (4) passing from the adsorption airflow outlet (39) through the discharge heat exchanger hot side. The discharge heat exchanger cold side can receive airflow from an external cooling unit (47). The external cooling unit (47) can comprise a passive cooling unit or an active cooling unit. The adsorption enthalpy associated with adsorption of water by the water capture material (3) in the adsorption mode (AM) in whole or in part can be transferred to the discharge air heat exchanger cold side and exhausted to the environment (48).

As depicted in FIGS. 1A and 1B and as described above, the process of adsorption of water (1) by the water capture material (3) is an exothermic process accompanied with release of adsorption enthalpy. That is, the airflow through a water capture module (6) during the adsorption mode (AM) increases in temperature which correspondingly lowers the driving potential of adsorption by the water capture material (3) and decreases the difference in absolute humidity (AH) between incoming supply air (2) passing through the water capture material (3) and the discharge air (4) passing out of the water capture module (6).

As depicted in FIGS. 2A through 2C, the discharge heat exchanger (46) coupled to the adsorption airflow outlet (39) of one or more of the plurality of water capture modules (6) can substantially reduce the temperature of the discharge air (4) passing from the adsorption airflow outlet (39). In embodiments in which a plurality of water capture modules (6) are fluidically coupled in series (as shown in the example of FIG. 4 modules M5 through M_n) the operation of the discharge heat exchanger (46) coupled to each adsorption airflow outlet (39) can correspondingly maintain or reduce the equilibrium temperature of adsorption of the water capture material (3) in the series, and can substantially reduce RH and AH of the discharge airflow (4) as compared to embodiments of the water harvester (5) without the discharge heat exchanger (46).

Again, with primary reference to FIG. 2B and FIGS. 3 through 5, the discharge heat exchanger cold side of the discharge heat exchanger (46) can receive airflow from the environment (48) at ambient temperature. In the illustrative example of FIG. 2B, the supply air (2) temperature into water capture module (6) (M1) can be at ambient temperature of 36° C. having RH 60% and having AH 22.7 g/kg. The discharge air (4) temperature from the water capture module (6) (M1) can be 55.5° C. having RH 15.7% and AH 15.0 g/kg. The difference in temperature between the supply air (2) temperature and the discharge air (4) temperature comprises the heat associated with the adsorption enthalpy of water capture module (6) (M1). The adsorption enthalpy associated with water capture module (6) (M1) can be in part or in whole offset by passing the discharge air (4) through the hot side of the discharge heat exchanger (46). In the example of FIG. 2B, the adsorption enthalpy has been entirely offset by the discharge heat exchanger (46) by reduction in the discharge air (4) temperature to 36° C. with an associated RH 42.6% and AH 16.0 g/kg.

Where water capture modules (6) (M1, M2 . . . M_n) operate in series as depicted in FIGS. 4 and 5, the discharge air (4) from each water capture module (6) (M1, M2 . . . M_n) can comprise the supply air (2) for next water capture module (6) (M2 . . . M_n) in the series. Where the adsorption enthalpy is entirely offset by passing the exhaust airflow from each water capture module (6) (M1, M2 . . . M_n) through a corresponding discharge heat exchangers (46) (HX1, HX2, . . . HX_n), the discharge air (4) delivered by the last water capture module (6) in the series, in comparison to water capture modules (6) (M1, M2 . . . M_n) operated in series without discharge heat exchangers (HX1, HX2, . . . HX_n), can have substantially lower RH and AH.

Now, with primary reference to FIG. 2C and FIGS. 3 through 5, the discharge heat exchanger (46) cold side can receive an airflow from an active external cooling unit (47) (also referred to as a “chiller” in the example of FIG. 2C). The active external cooling unit (47) operates to receive an intake airflow and generate an exhaust airflow having a lower temperature. The active external cooling unit (46) can operate by any method that dissipates heat from the intake airflow. As examples, the active external cooling unit (47) can take the form of a refrigeration cooler, chiller, or an evaporative cooler. In the illustrative example of FIG. 2C, the supply air (2) temperature into water capture module (6) (M1) can be ambient air temperature of 6° C. having RH 95% and having AH 5.5 g/kg. The discharge air (4) temperature from the water capture module (6) (M1) can be 17.4° C. having RH 12.3% and AH 1.51 g/kg. The difference in temperature between the supply air (2) temperature and the discharge air (4) temperature is the heat associated with the adsorption enthalpy of water capture module (6) (M1). In the example of FIG. 2C, the adsorption enthalpy of water capture module (6) (M1) has been offset by the discharge heat exchanger (46) (HX) having a cold side operating at 5° C. with a corresponding reduction in the discharge air (4) temperature to 5° C. with an associated RH 28% and AH 1.51 g/kg. Where water capture modules (6) (M1, M2 . . . M_n) operate in series as depicted in FIGS. 4 and 5, the discharge air (4) from each water capture module (M1, M2 . . . M_n) can comprise the supply air (2) for next water capture module (6) (M2 . . . M_n) in the series of water capture modules (6). Where the adsorption enthalpy is entirely or largely offset by passing the discharge air (4) from each water capture module (6) (M1, M2 . . . M_n) through a corresponding discharge heat exchanger (46) (HX1, HX2, . . . HX_n) each having a cold side at 5° C., the discharge air (4) delivered by the last water capture module (6) in the series of water capture modules (6) can be at 5° C. with an associated RH 12% and AH 0.6 g/kg, and in comparison to a plurality of water capture modules (6) (M1, M2 . . . M_n) operated in series without discharge heat exchangers (46) (HX1, HX2, . . . HX_n) or in comparison to a plurality of water capture modules (6) (M1, M2 . . . M_n) operated in series with discharge heat exchangers (46) (HX1, HX2, . . . HX_n) having a cold side operated at ambient temperature, the example of FIG. 2C can deliver a final discharge air (4) having substantially lower RH and AH.

Now, with primary reference to example of FIG. 6A, certain conventional vapor-compression cooling units (49) use a latent- and sensible-capable cooling coil (50) and a sensible heating coil (51) within the same vapor-compression cooling unit (49). The cooling coil (50) dehumidifies and cools the intake air while directing condensate into a drain pan while a sensible heating coil (51) reheats the cooled intake air to raise the temperature before discharge into the indoor space (35). This conventional process requires overcooling of the intake air by the cooling coil (50) to achieve dehumidification which substantially increases the load on a latent- and sensible-capable cooling coil (50) and the sensible heating coil (51) and decreases the coefficient of performance. The energy cost attributable to latent cooling increases with an increase in the ambient heat and humidity.

Now with primary reference to FIG. 6B, certain conventional vapor-compression cooling units (49) can be retrofitted with particular embodiments of the water harvester (5) to separate latent cooling from sensible cooling. In the illustrative example of FIG. 6B, an embodiment of the water harvester (5) including one or more water capture modules (6), where each can have the adsorption airflow outlet (39) coupled to a discharge heat exchanger (46), can be disposed in front of the air intake of a vapor-compression cooling unit (49). The water harvester (5) operates to remove water (1) from the supply air (2) to the water harvester (5) and the discharge heat exchanger (46) removes the adsorption enthalpy of the water adsorption process which can be passed to the ambient environment (48). Thus, the cooling coil (50) of vapor-compression cooling unit (49) does not have to be responsible for latent cooling but only be responsible for sensible cooling. The discharge air (4) from the water harvester (5) may only need to be cooled by the cooling coil (50) to the desired temperature of indoor space (35). Therefore, the energy cost attributable to latent cooling may be entirely offset and the energy cost attributable to sensible heating may be entirely offset. Thus, the coefficient of performance can be substantially greater than conventional vapor-compression cooling units (49) that have not been retrofitted with an embodiment of the water harvester (5).

Now, with primary reference to FIG. 7A, depicting an indirect evaporative cooler (52) operating to cool intake airflow for delivery to an indoor space (35) (in the example of FIG. 7A a “data center”). Under normal operating conditions, the practical wet-bulb efficiency (WBE) of the indirect evaporative cooler (52) does not exceed 90%, where:

W
⁢
B
⁢

E
⁡
(
%
)

=

Δ
⁢

T
conditioned

Δ
⁢

T
processed

=

T

dry
-
bulb

,
intake

-

T

dry
-
bulb

,
supply

T

dry
-
bulb

,
outdoor

-

T

wet
-
bulb

,
outdoor

Thus, where the intake air dry bulb temperature is 36° C.; 60% RH, the indirect evaporative cooler can only lower the air outlet temperature by 6° C. and be limited to a temperature of not lower than 29° C.

Now, with primary reference to FIG. 7B, depicting the conventional indirect evaporative cooler (52) including an embodiment of the water harvester (5), for example, in accordance with FIG. 2B. The intake airflow to the water capture module (6) (M1) can have a temperature of 36° C. at RH 60% and a wet bulb temperature of 29.1° C. and the discharge airflow (4) from water capture module (6) (M_n) can have a temperature of 36° C. at RH 21% and a wet bulb temperature of 20° C. The discharge air (4) from water capture module (6) M_ncan be delivered to the conventional indirect evaporative cooler (52) as the intake air and be exhausted from the conventional indirect evaporative cooler (52) as outlet air at 20° C. at 100% RH. The retrofit of the water harvester (5) to the conventional indirect evaporative cooler (52) expands the operating range of conventional indirect evaporative cooler by lowering the air outlet temperature from 36° C. to 20° C.

Now, with primary reference to FIGS. 1 and 8A, in particular embodiments, the example depicted in FIG. 2B as described above and the example depicted in FIG. 2C as described above can be combined to comprise a first plurality of water capture modules (6a) and a second plurality of water capture modules (6b), each of the first and the second plurality of water capture modules (6a, 6b) can be fluidically coupled in series as depicted in the examples of FIGS. 4 and 5 and operable in the absorption mode (AM). The supply air (2) can be outdoor air (2a) directed to the adsorption airflow inlet (38) of the first plurality of water capture modules (6a) fluidically coupled in series. The adsorption airflow outlet (39) of each of the first plurality of water capture modules (6a) can be fluidically coupled to a discharge heat exchanger (46) (HX1 . . . HX_n) hot side. The heat exchanger (46) cold side can be fluidically coupled to a passive external cooling unit (47a) (as shown in the example of FIG. 1 (47)) using natural conduction, convection, or radiation as the cooling component. As an example, the passive external cooling unit (47a) can comprise outdoor air (2a) at ambient temperature. The adsorption airflow outlet (39) of each of the second plurality of water capture modules (6b) can be fluidically coupled to a discharge heat exchanger (46) hot side. The discharge heat exchanger (46) cold side can be fluidically coupled to an active external cooling unit (47b) (as shown in the example of FIG. 1 (47)) which requires the use of energy specifically dedicated to the cooling component. As illustrative examples, the external active cooling unit (47b) can comprise an evaporative cooling unit as described above and depicted in FIG. 7A, a refrigeration cooler, or a chiller. In particular embodiments, the discharge airflow (4) from the final water capture module (6) in the series of water capture modules (6) operated in the adsorption mode (AM) can pass through a DEC (31) (as shown in the example of FIG. 1) which can operated to further cool or raise the RH of the discharge airflow (4). The conditioned air (8) can be directed to an indoor space (35).

Now, with primary reference to FIG. 1 and FIG. 8B, in particular embodiments, the example depicted in FIG. 2B as described above and the example depicted in FIG. 2C as described above can be combined to comprise a first plurality of water capture modules (6a) and a second plurality of water capture modules (6b), each of the first and the second plurality of water capture modules (6a, 6b) can be fluidically coupled in series as depicted in the examples of FIGS. 4 and 5 and operable in the absorption mode (AM). The supply air (2) can be indoor air (2b) from an indoor space (35) directed to the adsorption airflow inlet (38) of the first plurality of water capture modules (6a) fluidically coupled in series. The adsorption airflow outlet (39) of each of the first plurality of water capture modules (6a) and the second plurality of water capture modules (6b) can be fluidically coupled to a discharge heat exchanger (46) (H₁. . . HX_n) hot side as described above in example 8A. In particular embodiments, the discharge air (4) from the last water capture module (4) of the second plurality of water capture modules (6b) can pass through DEC (31) which can operate to further cool or raise the RH of the discharge airflow (4). The conditioned air (8) can be directed to an indoor space (35). The air from the indoor space (35) can be continuously or intermittently recirculated to the adsorption airflow inlet (38) of the first plurality of water capture modules (6a) fluidically coupled in series.

Now, with primary reference to FIG. 1 and FIG. 8C, in particular embodiments, the example depicted in FIG. 2B as described above and the example depicted in FIG. 2C as described above can be combined to comprise a first plurality of water capture modules (6a) and a second plurality of water capture modules (6b), each of the first and the second plurality of water capture modules (