The present disclosure relates generally to farming, and more specifically to atmospheric water and carbon dioxide harvesting systems suitable for integration into farming.
Water is scarce, especially in desert areas of North Africa and the Middle East. For this reason, conventional farming, requiring large amount of irrigation is often prohibitive. Hydroponics methods in green-house structures offer higher yields and water efficiencies, although the ratio of water-to-lettuce is still high. Vertical farming goes one step further, where leafy greens are grown on stacked shelves in large buildings, with controlled atmospheric conditions (e.g., temperature, humidity), and light being supplied by arrays of LED bulbs.
In order for plants to grow, not just water and light are needed. Plants in fact rely on atmospheric carbon dioxide as an essential component of photosynthesis, according to the following reaction:
6CO2+6H2O→C6H12O6+6O2 Eq(1)
In hydroponics and/or vertical farming, plants are also supplied with small amounts of mineral nutrients (e.g., phosphorus, nitrogen, iron, potassium). Today's hydroponics and vertical farming are also concerned about space utilization (e.g., urban areas) and cold weather with low insolation, in addition to the supply of fresh water. One issue is the high consumption of carbon dioxide, necessitating a constant exchange with outside air. This results in high heating cost, and waste of water/humidity. In some cases, pure carbon dioxide gas in injected into the building as a feed gas, but this comes at a significant cost as well. In urban areas, pure carbon dioxide is usually supplied by large trucks, but in remote, desert areas, this would be prohibitive proposition.
Thus, what is desired in the art are alternative systems that can provide both water and carbon dioxide to hydroponics and vertical farming.
In some aspects, provided is a farming system relying on renewal energy (e.g., solar, wind), where water and carbon dioxide are harvested from ambient air. In some variations, the system relies solely on renewable energy.
In certain aspects, provided is an atmospheric harvester, comprising: at least one unit containing water capture material, carbon dioxide capture material, or both, from surrounding air. When the system operates in adsorption mode, the at least one unit containing water capture material is configured to adsorb moisture from the air, and the at least one unit containing carbon dioxide capture material is configured to adsorb carbon dioxide from the air. When the system operates in production mode, the at least one unit containing water capture material is configured to desorb water vapor form the water capture material, the at least one unit containing carbon dioxide capture material is configured to desorb carbon dioxide from the carbon dioxide capture material. In some embodiments, the system is configured to condense the water vapor into liquid water, and optionally, cool the carbon dioxide.
In some embodiments, the atmospheric harvester comprises: at least one atmospheric water harvesting unit containing the water capture material; and at least one atmospheric carbon dioxide harvesting unit containing carbon dioxide capture material. In some variations, the water capture material and the carbon dioxide capture material independently comprise metal-organic frameworks.
In some variations of the foregoing, the atmospheric harvester further comprises one or more additional components, including for example, a heating element, a condensing unit, a vacuum pump, a control system, or a power source.
In certain aspects, provided is an integrated farming system comprising: any of the atmospheric harvesters described herein, configured to release water and carbon dioxide harvested from surrounding air into a farming system. In some embodiments, the farming system further comprises an oxygen reduction unit, such as an oxygen-permeable membrane, living organisms with oxygen-consuming metabolism and that produce proteins, or fuel such that the unit is configured to convert oxygen to carbon dioxide by combustion, or any combination thereof.
In other aspects, provided is a method of harvesting water and carbon dioxide from surrounding air using any of the atmospheric harvesters described herein. In some embodiments, the method comprises: adsorbing moisture from air in the at least one unit containing water capture material, and adsorbing carbon dioxide from air in the at least one unit containing carbon dioxide capture material; desorbing water vapor from the water capture material in the at least one unit containing water capture material, and desorbing carbon dioxide from the carbon dioxide capture material in the at least one unit containing carbon dioxide capture material; condensing the water vapor to produce liquid water: and, optionally, cooling the carbon dioxide.
In yet other aspects, provided is a method of farming, comprising: providing water and carbon dioxide harvested from surrounding air to a farming system, in which the water and carbon dioxide are harvested according to any of the methods for harvesting described herein; and growing crops in the farming system. In some embodiments, the methods provided further comprise: reducing or eliminating oxygen from air inside the farming system.
The present application can be understood by reference to the following description taken in conjunction with the accompanying figures.
The following description sets forth exemplary methods, parameters and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure but is instead provided as a description of exemplary embodiments.
In some aspects, provided is an atmospheric harvester that captures water and carbon dioxide from ambient air. In some embodiments, such atmospheric harvester is integrated in a farming system, such as hydroponics and/or vertical farming. For example, the atmospheric harvesters described herein may be incorporated into a vertical farming system, such as exemplary system 100 depicted in
In some embodiments, the atmospheric harvester comprises at least one unit containing water capture material, carbon dioxide capture material, or both. In certain embodiments, the atmospheric harvester comprises: at least one atmospheric water harvesting unit containing the water capture material, and at least one atmospheric carbon dioxide harvesting unit containing carbon dioxide capture material. In other embodiments, the atmospheric harvester comprises at least one unit containing a mixture of water capture material and carbon dioxide capture material, configured to simultaneously capture water and carbon dioxide.
With reference to
While
With reference to
In some variations, the atmospheric harvester may be configured to simultaneously desorb water vapor and carbon dioxide from their respective units. In other variations, the atmospheric harvester may be configured to desorb water vapor and carbon dioxide at different times.
A cooling process can be used to bring the effluent of water and carbon dioxide back to near-ambient temperature.
With reference again to
It should be understood that, in other embodiments, the atmospheric harvester includes one or more additional components. For example, in some variations, the atmospheric harvester includes a water collection unit, a control system, and power sources.
Any suitable materials that can capture water from air may be used as the water capture material. Similarly, any suitable materials that can capture carbon dioxide from air may be used as the carbon dioxide capture material. Such materials may be obtained from commercially available sources, or produced according to methods and techniques known in the art.
In some embodiments, the water capture material and the carbon dioxide capture material independently comprise metal-organic frameworks (MOPs). MOFs are porous materials that have repeating secondary building units (SBUs) connected to organic ligands. In some variations, the SBUs may include one or more metals or metal-containing complexes.
The units containing the water capture material and carbon dioxide capture material can be made of porous MOF material, MOP-coated substrates, or any combination thereof.
Water Capture Materials
In some embodiments, the water capture material can selectively capture water from the atmosphere.
In some variations, the water capture material is a MOF, in which the organic ligands have acid and/or amine functional group(s). In certain variations, the organic ligands have carboxylic acid groups. In other variations, the organic ligands have acid and/or amine functional group(s). In certain variations, the organic ligands have carboxylic acid groups.
Any suitable MOFs capable of adsorbing and desorbing water may be employed in the systems provided herein. Suitable MOF's may include those described in, for example, Kalmutzki et al., Adv. Mat., 30(37), 1704304 (2018); Furukawa et al., J. Am. Chem. Soc. 2014, 136, 4369-4381; Y. Tu et al, Joule, Vol 2, Issue 8(15), 1452-1475 (2018).
In some variations, the water capture material comprises:
In some variations, the MOFs have pore sizes between about 0.5 nm about 1 nm, or between about 0.7 nm to about 0.9 nm. In certain variations, the MOFs have a hydrophilic pore structure. In certain variations, the MOFs have a hydrophilic pore structure comprising acid and/or amine functional groups. In certain variations, the MOFs have 1D channels that allow for reversible water adsorption.
In other variations, the water capture material is a desiccant material. Any suitable desiccant material may be used.
Any combinations of the water capture materials described herein may also be used.
In some embodiments, the water capture material is mixed with a binder to improve its properties for adhesion to a substrate.
Carbon Dioxide Capture Material
In some embodiments, the carbon dioxide capture material can selectively capture carbon dioxide from the atmosphere.
In some variations, the carbon dioxide capture material is a MOF, in which the organic ligands have amine functional groups, including primary amines, that can bind carbon dioxide molecules via chemisorption even in presence of water molecules.
Any suitable MOFs capable of adsorbing and desorbing carbon dioxide may be employed in the systems provided herein. Suitable MOFs may include those described in, for example, M. Ding, et al., Chem. Soc. Rev., 2019, 48, 2783-2828; A. M. Fracaroli, et al, J. Am. Chem. Soc., 2014, 136, 8863-8866; H. Li, et al., ChemSusChem., 2016, 9, 2832-2840.
In some variations, the carbon dioxide water capture material comprises:
IRMOF-74-III-CH2NH2: {Mg2(2′-(aminomethyl)-3,3″-dioxido-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylate)};
IRMOF-74-III-(CH2NH2)2: {Mg2(2′,5′-bis(aminomethyl)-3,3″-dioxido-[1,1′:4′,1″-terphen-yl]-4,4″-dicarboxylate)};
mmen-Mg2(dobpdc): Mg2(dobpdc)(mmen)1.6(H2O)0.4, where dobpdc is 4,4′-dioxido-3,3′-biphenyldicarboxylate and mmen is N,N′-dimethylethylenediamine;
Mg2(dobdc)(N2H4)1.8: Mg2(dobdc)(N2H4)1.8, where dobpdc is 4,4′-dioxido-3,3′-biphenyldicarboxylate;
Cr-MIL-101-SO3H-TAEA: Cr3O(OH)(BDC-SO3)(H2O)2(TAEA), where BDC-SO3 is 2-sulfoterephthalate and TAEA is Tris(2-aminoethyl)amine; or
Cr-MIL-101-PEI-800: Cr3O(OH)(BDC)(PEI-800), where PEI-800 is polyethylenimine, branched.
Any combinations of the carbon dioxide capture materials described herein may also be used.
In some embodiments, the carbon dioxide capture material is mixed with a binder to improve its properties for adhesion to a substrate.
In some variations, any combinations of the water and carbon dioxide materials described herein may be used.
In some embodiments, the relative mass of water and carbon dioxide capture materials in the system can be tailored to the humidity condition of a given region. For instance, very arid regions will necessitate an excess of water capture material, whereas relatively humid region will need a larger amount of carbon dioxide capture material.
In some variations, the amount of water and carbon dioxide capture materials may be pre-determined by the relative humidity and temperature level in the particular climate. This can be an installed feature of the system, such that amount of material in the system will not change throughout the operation.
Collection Units
In some embodiments, the atmospheric harvester is integrated into a farming system, as described in further detail. The water and carbon dioxide can be released directly into the farming system.
In other embodiments, the atmospheric harvester comprises at least one collection unit, configured to receive, and optionally store, the liquid water and carbon dioxide generated. In some variations, the collection unit is a storage tank.
Control System
In some embodiments, the atmospheric harvester includes a control system configured to monitor and control adsorption, desorption, and condensation. In some embodiments, the control system includes one or more sensors and one or more processor units.
In some embodiments, the control system monitors and controls the water and carbon dioxide harvesting based on environmental conditions such as temperature and humidity. In some embodiments, temperature or humidity sensors are placed inside or near the water and/or carbon dioxide harvesting units.
In some embodiments, the control system monitors and controls the atmospheric harvester to maximize the total water and/or carbon dioxide captured over multiple adsorption and desorption cycles, as opposed to optimizing the adsorption or desorption amounts individually.
Power Sources
In some variations, the atmospheric harvester further include one or more solar power source(s). In certain variations, the systems further include photovoltaic (PV) cells or passive solar captors, or a combination thereof
In certain aspects, provided is an integrated farming system, comprising: an atmospheric harvester as described herein integrated to release water and carbon dioxide captured from surrounding air into a farming system. In some embodiments, the farming system is a hydroponic farming system. In other embodiments, the farming system is a vertical farming system. In certain variations of the foregoing, the farming system is in a sealed enclosure, or the farming system is in a sealed environment.
One of skill in the art would appreciate that another important feature of photosynthesis is the production of oxygen, as seen in Eq(1) above. In a sealed farming system, oxygen would accumulate and plants would ultimately not survive. Thus, in some variations, the farming systems described herein further comprise an element configured to reduce or eliminate oxygen from the air inside the farming system.
In some variations, the farming system further comprises an oxygen reduction unit that evacuates excess oxygen and equilibrates the nitrogen:oxygen ratio with the outside air. In certain variations, the oxygen reduction unit comprises an oxygen-permeable membrane. In one variation, the use of an oxygen exchanger is shown schematically in
In other variations, the farming system can utilize living organisms to evacuate excess oxygen and equilibrate the nitrogen:oxygen ratio with the outside air. In some variation, the farming system comprises animals with a metabolism that is the reverse of Eq(1). In some embodiments, the atmospheric harvesters described herein can be used with farming systems, such as exemplary farming system 400 as depicted in
In other variations, the farming system can utilize a source of fuel to convert oxygen to carbon dioxide, using combustion. In some embodiments, the atmospheric harvesters described herein can be used with farming systems, such as exemplary vertical farming system depicted in
0.1 This application claims priority to U.S. Provisional Patent Application No. 63/072,525, filed Aug. 31, 2020, which is incorporated herein by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/047491 | 8/25/2021 | WO |
Number | Date | Country | |
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63072525 | Aug 2020 | US |