WO2021184050A2

WO2021184050A2 - An aeroponic plant growing system and method

Info

Publication number: WO2021184050A2
Application number: PCT/ZA2021/000002
Authority: WO
Inventors: Peter Dudley WINDSOR; Michael Mettler
Original assignee: Windsor Peter Dudley; Michael Mettler
Priority date: 2020-03-09
Filing date: 2021-03-09
Publication date: 2021-09-16
Also published as: WO2021184050A3

Abstract

An aeroponic growing system comprising a bulk liquid reservoir, located at least partially underground to provide a heat regulator to the liquid, at least one growing chamber, having at least one plant supporting formation for supporting at least one plant with the plant roots being suspended at least partially within the chamber. The aeroponic growing system further comprising at least one liquid line in fluid communication between the reservoir and the chamber and wherein the liquid line extends between the chamber and the reservoir such that the liquid can be recirculated from the reservoir to the chamber, means for conveying liquid from the reservoir via the liquid line to the chamber at a predetermined flow rate and under a predetermine pressure, at least one sprayer, coupled to the liquid line in the growing chamber and positioned to spray liquid from the reservoir at the plant roots at a predetermined frequency and droplet size for at Ieast one predetermined time interval for optimum liquid-contact to oxygen-exchange on the root surface, a suitable power source for powering the liquid conveying means and at least one drain line in liquid communication between the chamber and the reservoir to allow sprayed liquid to drain from the plant roots or the chamber to the liquid reservoir.

Description

AN AEROPONIC PLANT GROWING SYSTEM AND METHOD

Field of the Invention

[001] The invention relates to a resource efficient aeroponic plant growingw ingtem and method.

Background to the Invention

[002] Traditional horticulture or crop farming comprises farming systems that use soil as a solids-based, root-growth medium, and synthetic chemical fertilizers, pesticides, herbicides and other continual inputs, intensive tillage, concentrated monoculture production and even irrigation. Traditional horticulture is substantially dependent on the climate where the plants are grown. Traditional horticulture has led to several ecological ramifications, including water pollution, due to chemical leaching, land degradation, in the form of erosion and soil compaction, substantial resource usage and an overall loss in biodiversity.

[003] Due to the substantial amount, and variety, of resources that are required for traditional horticulture, many commercial and non -commercial farmers have commenced employing hydroponic and even aeroponic farming systems.

[004] Hydroponic farming systems comprise systems wherein the soil as plant root-growth medium is substituted with a fluid-based, root-growth medium, by having the plant roots suspended in mineral nutrient solutions in a water solvent medium. In some cases, the root systems are further supported physically with the use of an inert medium such as perlite, gravel or an expanded clay aggregate. Hydroponic farming systems uses approximately 90% less water when compared to traditional (sol) horticulture. However, hydroponic systems still require substantial amounts of nutrients to be added to the water solvent, espedally in cases where the water solvent is recycled or rehabilitated in an effort to reduce water usage. Additionally, due to the fact that the nutrient-rich water solvent is passed between the plant roots, water-based diseases travel and spread rapidly between the plants in the system. Further, hydroponic farming systems are relatively expensive to implement on a large commercial scale for most farmers. Examples of such systems indude US Patent No. 4,279,101 entitled "MODULAR HYDROPONIC SYSTEM", and US Patent No. 4,315.361 entitled "AUTOMATIC HYDROPONIC GARDEN",

[005] Aeroponic farming systems comprise systems wherein solids [e,g. soli], as root- growth medium, is substituted with an air-based (i.e. gaseous), root-growth medium, by having the plant roots suspended in an air or mist environment rather than soil or nutrient- rich water solvents. These systems typically suspend the plant roots with the assistance of a support medium into a lower, closed-air environment or chamber wherein nutrients and other sustenance (e.g. a nutrient-rich water solution) for the plant are sprayed or misted onto the suspended roots, while the leaves and the crown of the plants extend upwardly from the support-medium into an upper, open environment. Unlike traditional horticulture or hydroponics, aeroponic farming is conducted without a solid s-based (e.g. soil) or liquid- based (e.g. nutrient-rich water solvent), root-growth medium. The aeroponic conditions are deemed to advance plant development, health, growth, flowering and fruiting for any given plant species relative to traditional horticulture or hydroponic systems. Aeroponic farming systems are typically applied in so-called “vertical farms" in urban or indoor environments wherein multiple rows or layers of aeroponic farming systems are stacked on top of each other due to the limited floor space or agricultural soil available in those areas. Examples of such systems include US Patent No. US9974243 B2 entitles ‘SYSTEMS, METHODS AND DEVICES FOR AEROPONIC PLANT GROWTH*, and US 2021/0085026 A1 entitled ^•EXPANDIBLE AEROPONIC GROW SYSTEM”.

[006] Aeroponic farming systems provide a variety of desirable advantages over growing systems that employ a solids- of liquid-based, root-growth medium. In general, aeroponic systems are favoured over other methods due to increased oxygen delivery as a result of efficient nutrient solution aeration to plant roots, stimulating growth and helping to prevent pathogen formation. Aeroponic growing is considered to be safe and ecologically friendly for producing natural, healthy plants and crops. The main ecological advantages of aeroponics are the conservation of water and energy. When compared to hydroponics, aeroponic systems require relatively lower water and energy inputs per square meter of growing area. Additionally, these systems typically use less fertilizer compared to hydroponic farming systems due to aeroponic farming systems using less nutrient-enriched water. However, conventional aeroponic systems stiil placed substantial loads on the energy and water resources and infrastructures, for purposes of lighting, heating and cooling as well as water, especially due to most systems being located indoors to benefit from the protection provided against fluctuating environmental conditions.

[007] More particularly and due to the fact that the roots of plants in an aeroponic farming system are exposed to an open, oxygen-rich climate that is subject to frequent changes In conditions, more specifically, temperature and humidity, it is critical to control the climate on a constant basis, as small changes to the climate can cause the roots, and thereby the plant, to die. Therefore, in order to consistently control the climate at a high level of sensitivity, general aeroponic farming systems typically are provided with electronic temperature- and humidity-control mechanisms that are expensive and require substantial amounts of uninterrupted electricity in order to effectively operate.

[008] Generally, aeroponic farming systems are accordingly developed for and therefore applied indoors due to the sensitivity of the systems to external influences such as material temperature fluctuations, and hence the need for climate-controlled environments, typically using artificial light for photosynthesis and the subsequent cultivation of plants. Indoor aeroponic systems do use a considerable amount of electricity to power the artificial lights, humidity- and temperature-controlling mechanisms. Additionally, due to the spatial requirements for indoor aeroponic systems, these systems usually comprise of multiple rows or layers of systems that are stacked on top of each other to optimise resources such as space, heat and water in an efficient manner. However, because of the space restrictions due to space optimisation in these so-called "vertical-farm" root chambers, the systems have a limited size and can therefore often not accommodate the roots from larger plants.

[009] There is accordingly a need for an aeroponic farming system that (i) is resource efficient, (S) is capable of being used outdoors to reduce the load on limited and expensive power and water resources by benefiting from replaceable resources such as natural light and solar energy, (Hi) is extendable to enable increased capacity, (iv) can support a broad range of plant species, including but not limited to above-ground products, root harvests, such as potatoes and ginger, medicinal roots, such as Valerian root, and the like, and (v) has a predetermined isolation capability to limit losses due to external influences.

Summary of the Invention

[0010] According to a first aspect of the invention there is provided an aeroponic growing system, comprising: a bulk liquid reservoir, located at least partially underground to provide a heat regulator to the liquid; at least one growing chamber, having at least one plant supporting formation for supporting at least one plant with the plant roots being suspended at least partially within the chamber; at least one liquid line in fluid communication between the reservoir and the chamber and wherein the liquid line extends between the chamber and the reservoir such that the liquid can be recirculated from the reservoir to the chamber; means for conveying liquid from the reservoir via the liquid line to the chamber at a predetermined flow rate and under a predetermine pressure; at least one sprayer, coupled to the liquid line In the growing chamber and positioned to spray Squid from the reservoir at the plant roots at a predetermined frequency and droplet size for at least one predetermined time interval for optimum Squid-contact to oxygen- exchange on the root surface; a suitable power source for powering the Squid conveying means; and at least one drain line in liquid communication between the chamber and the reservoir to allow sprayed liquid to drain from the plant roots and/or the chamber to the liquid reservoir.

[0011] The means for conveying liquid at a predetermined flow rate and under a predetermine pressure from the reservoir via the liquid line to the chamber may comprise a solenoid activated, high-pressure pump-and-hydraulic accumulator arrangement, suitable for releasing high-pressure liquid intermittently to the sprayer.

[0012] The power source may comprise a rechargeable solar battery and solar cell arrangement and. preferably, comprises a low voltage, rechargeable solar battery and a bank of solar cells. The power source may operate at between 6 volt and 60 volt and, preferably, at about 12 volt.

[0013] The aeroponic growing system may be provided with a predetermined chamber- volume to root-size ratio to optimize the oxygen exchange between the roots and the environment inside the chamber.

[0014] The aeroponic growing system may include means for drawing external air at ambient temperature into the chamber to adjust the temperature inside the chamber towards the ambient temperature and for drawing internal air from within the reservoir into the chamber to adjust the temperature inside the chamber towards the reservoir air temperature within predetermined ranges so as to maintain optimum root-growth conditions within the chamber while minimizing energy consumption.

[0015] The aeroponic growing system may be provided with at least one solar Squid heater for heating the reservoir liquid to a preselected temperature to enable relatively heated reservoir liquid and/or reservoir air to convey heat during circulation to the chamber when the external ambient temperature drops below the optimal levels.

[0016] The aeroponic growing system may be of a modular design to render the system modularly extendable to increase capacity in predetermined increments, the system preferably including at least one of the components selected from the group comprising; a modular bulk liquid reservoir, locatable at least partially underground to provide a heat regulator to the liquid; a set of modular growing chambers, having a predetermined number of plant-supporting formations for supporting a corresponding number of plants with the plant roots being suspended at least partially within the corresponding chambers; a set of modular liquid lines in fluid communication between the reservoir and the corresponding chambers and wherein the liquid lines extend between the chambers and the reservoir such that the liquid can be recirculated between the chambers and the reservoir; modular means for conveying liquid from the reservoir via the liquid lines to the chambers at a predetermined flow rate and pressure; a modular set of sprayers, coupled to the liquid lines in the growing chambers and positioned to spray liquid from the reservoir at the plant roots at a predetermined droplet size and frequency for predetermined time intervals; a suitable modular power source for powering the liquid conveying means; and a set of modular drain lines in liquid communication between the corresponding chambers and the reservoir to allow sprayed liquid to drain from the plant roots or the chambers to the liquid reservoir.

[0017] According to a second aspect of the invention there is provided a method for growing plants in an aeroponic growing chamber, the method including the steps of: storing bulk liquid at least partially underground in a suitable reservoir, thereby at least partially regulating the heat exchange between the liquid and its surroundings; supporting at least one plant in at least one growing chamber by suspending the plant roots at least partially within the chamber; circulating the liquid in a substantially closed loop between the chamber and the reservoir; spraying liquid from the reservoir at the plant roots at a predetermined droplet size and frequency for at least one predetermined time interval; and draining sprayed liquid from the plant roots or the chamber to the liquid reservoir.

[0018] The method may include the steps of: drawing external air at ambient temperature Into the chamber to adjust the temperature inside the chamber towards the ambient temperature; and drawing internal air from the reservoir Into the chamber to adjust the temperature inside the chamber towards the reservoir air temperature; so as to maintain optimum root-growth conditions within the chamber within predetermined ranges while minimizing energy consumption. [0019] The method may include the step of circulating the water and/or air flows to or from the reservoir to increase or decrease the water and/or air temperatures within predetermined ranges so as to maintain optimum root-growth conditions within the chamber.

[0020] According to a third aspect of the invention there Is provided a kit for an aeroponic growing system, the kit including: at least one bulk liquid reservoir, iocatable at least partially underground to provide a heat regulator to the liquid; at least one growing chamber, having at least one plant supporting formation for supporting at least one plant with the plant roots being suspended at least partially within the chamber, at least one liquid line for providing fluid communication between the reservoir and the chamber and wherein the liquid line is designed and dimensioned to extend between the chamber and toe reservoir in an erected format such that the liquid can be recirculated between the chamber and the reservoir; means for conveying liquid from the reservoir via the liquid line to the chamber at a predetermined flow rate and pressure; at least one sprayer, capable of being positioned in the growing chamber and coupled to the Nquid line to spray liquid from the reservoir at the plant roots at a predetermined droplet size and frequency for at least one predetermined time interval; a suitable power source for powering the liquid conveying means; and at least one drain line for providing liquid communication between the chamber and the reservoir in the erected format to allow sprayed liquid to drain from the plant roots and/or the chamber to the liquid reservoir,

[0021] The kit may be of a modular design to render the resulting system modularty extendable to enable Increased capacity in predetermined increments, the kit preferably including at least one of the components selected from the group comprising: a modular bulk liquid reservoir, Iocatable at least partially underground to provide a heat regulator to the liquid; a set of modular growing chambers, having a predetermined number of plant supporting formations for supporting a corresponding number of plants with the plant roots being suspended at least partially within the corresponding chambers; a set of modular liquid lines for providing fluid communication between the reservoir and the corresponding chambers in the erected format and wherein the liquid line extends between the chambers and toe reservoir such that the liquid can be recirculated between the chambers and the reservoir; means for conveying liquid from the reservoir via the liquid lines to the chambers at a predetermined flow rate and pressure; a set of modular sprayers, capable of being positioned in the growing chambers and coupled to the liquid tines to spray liquid from the reservoir at the plant roots at a predetermined droplet size and frequency for predetermined time intervals; a suitable modular power source for powering the liquid conveying means; and a set of modular drain lines for providing liquid communication between the corresponding chambers and the reservoir in the erected format to allow sprayed liquid to dram from the plant roots or the chambers to the liquid reservoir.

[0022] The kit may indude means for drawing external air at ambient temperature into the chamber to adjust the temperature inside the chamber towards the ambient temperature and for drawing internal air from within the reservoir into the chamber to adjust the temperature inside the chamber towards the reservoir air temperature within predetermined ranges so as to maintain optimum root-growth conditions within the chamber while minimizing energy consumption.

[0023] The kit may include at least one liquid heater for heating the reservoir liquid to a preselected temperature to enable relatively heated reservoir liquid and/or reservoir air to convey heat during circulation to the chambers when the external ambient temperature drops below the optimal levels.

Detailed Description the Invention

[0024] A non-limiting embodiment of the invention shall now be described with reference to the accompanying drawings wherein:

Figure 1 is a cross sectional side view of a resource efficient aeroponic farming system in accordance with the invention; and

Figure 2 is a perspective top view of the system as illustrated in Figure 1.

[0025] An aeroponic farming system 1 in accordance with the invention and as illustrated in Figure 1 and 2 comprises a plurality of multi-coated, thin steel walled chambers 2, each chamber having two opposed, elongated side walls 2A, each side wail with a lower portion 2B and an upper portion 2C, and two opposed end walls 2D, the chambers providing a light- tight environment wherein the roots of plants grown therein (not shown) can be suspended. It is envisaged that the dimensions of the chambers 2 can vary depending on the type of crop being planted to ensure that there is sufficient room for the roots of such plants to grow in a high air-volume environment The outside of the chambers 2 are covered with reflective thermal aluminum insulation foil 3 that ensures that the temperature within the chambers are not substantially influenced by the ambient temperatures outside the chambers. It is however envisaged that any other suitable and commercially available insulation can be used for this purpose. The lower portions 2B of the opposing side walls 2A of the chambers 2 are tapered inwardly into an angled bottom to form a substantially v-shaped channel 4 at the bottom of each chamber. The v-shaped channels 4 allow for effective drainage of any liquid run-off from plant roots and the upper portions of the side walls 2C of the chambers 2. The chambers 2 are further arranged side by side to create a lateral field configuration similar to so-called row-crop and table-top configurations.

[0026] The chambers 2 are provided with support steel chamber lids 5, resting loosely on top of the chambers, the lids being provided with edging formations (not shown) that serve as locating guides. It is however envisaged that the lids 5 can alternatively be hinged to the side walls 2A. The lids 5 are reinforced with embossed ribs and edging to increase the lids’ rigidity and load bearing capacity. A number of apertures 21 are provided towards the upper edges of the opposing side walls 2A and the chamber lids 5 to allow sufficient fresh air flow through the chambers 2. Additionally, the lids 5 are provided with a plurality of perforations 6 that are flared and tapered, wherein net cups 7 can be suspended in a stable position. The plants being grown are held and supported by the net cups 7 while their roots are threaded through lower openings (not shown) in the net cups and allowed to dangle In the gaseous root-growth medium within the chambers 2. The number and size of the perforations 6 can vary depending on the physical dimensions of the plant variety(ies) being grown in the aeroponic farming system 1.

[0027] The diambers 2 are supported with height-adjustable T-members 8 that can be adjusted to support the chambers at an angle that will allow for the optimal drainage of any liquid run-off from the plant roots (not shown) and the side walls 2A of the chambers. The T- members 8 are anchored to the base, typically the ground, to provide a stable support for the chambers 2.

[0028] Open ended air circulation and liquid drainage pipes 9A and 96 are provided, extending vertically through the base of the chambers 2 via a series of regularly spaced apertures (not shown) in the v-shaped channels 4 Into the upper chambers. The air circulation and liquid drainage pipes 9A and 8 have open lower and open upper ends (not shown), the open lower ends being located in the v-shaped channels 4 at the bottom of the chambers 2 and the upper ends being positioned towards the chamber Iids 5. Additionally, small Squid drainage holes (not shown) are provided towards the open lower ends (not shown) of the circulation and liquid drainage pipes 9A and B end in the v-shaped channels 4 at the bottom of the chambers 2. The air circulation and liquid drainage pipes 9A and B have the dual purpose of simultaneously drawing warm humid air downwardly from the chambers 2, while draining any excess liquid run-off downwardly from the roots and the side walls of the chambers.

[0029] The air circulation and liquid drainage pipes 9A and B are Niter-connected to a subterranean air suction and liquid drainage pipe 10 that is embedded underground beneath the chambers 2. In warm ambient conditions, the geo-thermal properties of the soil surrounding the air suction and liquid drainage pipe 10 cools the warm humid air and the liquid run-off that passes through it down. Additionally, the cooling down of the warm humid air causes condensation on the surface of the air suction and liquid drainage pipe 10, leading to greater retention of the liquid being captured for recirculation.

[0030] An ultraviolet light 24 is provided, coupled in line with the air suction and liquid drainage pipe 10 to remove any pathogens present in the liquid that is collected from the chambers 2 before it is recirculated.

[0031] The aeroponic farming system 1 is provided with a subterranean collection reservoir 11 for receiving and collecting warm humid air and liquid that respectively is drawn and drained from the warm chambers 2. The reservoir 11 is embedded underground beneath the chambers 2 and connected to the chambers via the air suction and liquid drainage pipes 10 for receiving the warm humid air and liquid from the chambers 2 there through. The underground reservoir 11 utilizes the geo-thermal properties of the surrounding soil as a heat regulator to cool down the relatively warmer humid air and liquid from the chambers during warmer times. In addition, the collection reservoir 11 also stores the drained liquid it has collected for use recirculation in the system 1.

[0032] Similarly and in relatively colder times and/or in environments where the external ambient temperature might drop below the required levels, the underground reservoir 11 utilizes the geo-thermal properties of the surrounding soil as a heat regulator to regulate the heat exchange between the liquid and the air and their surroundings. The liquid in the reservoir 11 could further be heated with the use of heat generators (not shown) such as solar geysers to convey heat with the circulating liquid to the chambers during relatively colder times and/or in environments where the external ambient temperature might drop below the required levels. [0033] The collection reservoir 11 should preferably be large enough to contain a sufficient quantity of liquid such that the collection reservoir does not need to be refilled too often, thereby saving time and labour. It is envisaged that the optimum size of the collection reservoir 11 would depend on various factors, including the number of plants to be grown in the system 1. the variety of the plants, the required growing conditions, etc.

[0034] The aeroponic forming system 1 is provided with a network of liquid distribution lines 15, extending into the chambers 2 via a set of appropriately sized apertures 16 in the side walls 2A of the chambers.

[0035] The aeroponic farming system 1 is further provided with a solenoid activated, high pressure pump-and-hydraulic accumulator arrangement, comprising a pump 12 and a accumulator 13. activated by means of a solenoid 27. for conveying the liquid stored in the collection reservoir 11 at a predetermined fixed, alternatively variable flow rate and pressure via the distribution lines 15 into the chambers 2. The liquid distribution lines 15 traverse the entire length of the chambers 2 and are joined at the opposing side walls 2A of the chambers for structural support.

[0036] The aeroponic farming system 1 includes a set of sprayers in the form of pressure compensated misting nozzles 17, connected to sections of the liquid distribution lines 15 that traverse the chambers 2. The nozzles 17 are spaced regular intervals at predetermined distances along the sections of liquid distribution lines 15 that are inside the chambers 2 and are operatively aligned to face the net cups 7 and the roots of the plants being supported in the net cup to provide optimum directional and volumetric fluid flow to the plants and their roots. The misting nozzles 17 and the pressure applied in the system 1 are further both of predetermined design and configuration to provide a selected droplet size and frequency to ensure optimum balance between liquid and nutrient contact with the roots while maintaining optimum oxygen exchange between the roots and the environment inside the chambers 2.

[0037] The aeroponic farming system 1 further includes an electronic controller 18 that la operatively connected to the solenoid 27 activated, high pressure pump-and-hydraulic accumulator arrangement 12 &13 and the pressure regulator 14 for controlling the pressure regulator. In operation, the electronic controller 18 activates the pump-and-hydraulic accumulator arrangement 12 & 13, which then pumps the liquid to the accumulator at the required flow rate until the pressure inside the accumulator has reached a preselected level (6 Bar or 87 Psi), where after the electronic controller deactivates the pump 12 while the pressurised liquid is housed in the accumulator 13 until the liquid is released by means of the solenoid 27 and through the liquid distribution lines 15 at a predetermined flow rate (and velocity) to the misting nozzles 17, where the pressurised liquid is sprayed as a fine mist on to the roots that are dangling in the chambers 2. After the required volume of pressurised liquid has been released in mist form, the electronic controller 18 reactivates the pump 12, thereby re-pressurizing the liquid in the accumulator 13 and repeats the release cycle. The timing, duration and volumetric requirements of the pressurised mist cycles are adjustable via the electronic controller 18 in accordance with the climatic, temperature and growth-cycle requirements of specific plant varieties being cultivated.

[0038] The aeroponic farming system 1 is additionally provided with a series of wetness sensors 19 and temperature sensors 20 located within the chambers 2, the sensors respectively coupled electronically to the electronic controller 18. The plant surface and climatic conditions such as wetness and temperature within the chambers 2 are accordingly measured inter alia via the wetness and temperature sensors 19 and 20 and controlled via the electronic controller 18 on a substantially real-time basis. The specific operational and climatic parameters can further be varied according to the external conditions and the specific plant variety being grown with the system 1. More particularly, an operator (not shown) of the system 1 can calibrate the specific operational and climatic parameters required for the plants and their roots via the electronic controller 18 by selecting and maintaining the specific parameters within the chambers 2, including the temperature and wetness inside the chambers.

[0039] Temperature control Is primarily accomplished via selected manipulation of the electronic controller 18, by periodically or routinely releasing the pressurised liquid from the pump-and-hydraulic accumulator arrangement 12 & 13 so as to generate mist the inside of the chambers 2 via the misting nozzles 17, thereby decreasing (or increasing) the temperature inside the chambers with the geothermally cooled (or healed) mist, simultaneously with providing the roots of the plants with the required liquid and nutrients.

[0040] Additionally, the aeroponic farming system 1 is provided with a set of fans 22 that are electronically coupled to the electronic controller 18 and operably connected to the air circulation and Squid drainage pipes 9. The fans 22, once activated, are arranged in associated with a series of air valves (not shown), first, to draw warm humid air from the inside of the chambers 2, if the temperature rises above a preselected level within the chambers, as measured with the use of the temperature sensors 20. while drawing fresh air into the chambers 2 through the apertures 21. Second and if the temperature drops beiow a preselected level within the chambers 2, the fans 22 and air valves (not shown) are arranged to draw warm humid air into the chambers 2 via air delivery pipes 23 from the reservoir 11. [0041] Wetness control is similarly accomplished via selected manipulation of the electronic controller 18, by periodically or routinely releasing the pressurised liquid from the pump-and-hydraulic accumulator arrangement 12 & 13 so as to generate mist the inside of the diambers 2 via the misting nozzles 17, thereby increasing the wetness inside the chambers and/or on the piants with the mist, simultaneously with providing the roots of the plants with the required nutrients. If the wetness level inside the chambers 2 exceeds a preselected level within the chambers, as measured with the use of the wetness sensors 19, the electronic controller 18 increases the time intervals between consecutive misting cycles. If the wetness level inside the chambers 2 drops below a preselected level within the chambers, the electronic controller 18 decreases the time intervals between consecutive misting cycles.

[0042] The aeroponic farming system 1 is provided with a 12 volt rechargeable solar battery 25 and a bank of solar cells 26 for powering the pump 12, electronic controller 18, wetness sensors 19, temperature sensors 20 and set of fans 22.

[0043] The aeroponic farming system 1 is also provided with an alarm system (not shown), connected to the electronic controller 18, for notifying the operator (not shown), should a failure occur with the operating components, such as the pump 12 or set of fans 22, an unacceptable pressure level be reached within the pump-and-hydraulic accumulator arrangement 12 & 13 or if the temperature or wetness levels rise or drop above or below acceptable levels in the system and/or its components. It is envisaged that the alarm system (not shown) can be a proximity-based alarm, such as lights and/or alarms sounds, can be linked to an operator's mobile phone, whereby notifications will be transmitted to the operator's phone, or can be in communication with some other remote device as required or available from time to time.

[0044] It will be appreciated that there are many variations in) detail without departing from the scope or spirit of the invention as defined in the consistories or described in the specific description hereinabove.

Claims

Claims:

1. An aeroponic growing system, comprising: a bulk liquid reservoir, located at least partially underground to provide a heat regulator to the liquid·, at least one growing chamber, having at least one plant supporting formation for supporting at least one plant with the plant roots being suspended at least partially within the chamber; at least one liquid line in fluid communication between the reservoir and the chamber and wherein the liquid line extends between the chamber and the reservoir such that the liquid can be recirculated from the reservoir to the chamber; means for conveying liquid from the reservoir via the liquid line to the chamber at a predetermined flow rate and under a predetermine pressure; at least one sprayer, coupled to the liquid line in the growing chamber and positioned to spray liquid from the reservoir at the plant roots at a predetermined frequency and droplet size for at least one predetermined time interval for optimum liquid-contact to oxygen-exchange on the root surface; a suitable power source for powering the liquid conveying means; and at least one drain line in liquid communication between the chamber and the reservoir to alow sprayed liquid to drain from the plant roots or the chamber to the liquid reservoir.

2. The aeroponic growing system as claimed in claim 1 wherein the means for conveying liquid at a predetermined flow rate and under a predetermine pressure from the reservoir via the liquid line to the chamber comprises a solenoid activated, high-pressure pump- and-hydraulic accumulator arrangement, suitable for releasing high-pressure liquid intermittently to the sprayer.

3. The aeroponic growing system as claimed in claim 1 wherein the power source comprises a rechargeable solar battery and solar cell arrangement, operable at between 6 volt and 60 volt.

4. The aeroponic growing system as claimed in claims 1 to 3 having a predetermined chamber-volume to root-size ratio to optimize the oxygen exchange between the roots and the environment inside the chamber.

5. The aeroponic growing system as claimed in claim 1 having means for drawing external air at ambient temperature into the chamber to adjust the temperature inside the chamber towards the ambient temperature and for drawing internal air from within the reservoir into the chamber to adjust the temperature inside the chamber towards the reservoir air temperature within predetermined ranges so as to maintain optimum root-growth conditions within the chamber while minimizing energy consumption.

6. The aeroponic growing system as claimed in claim 1 having at least one solar liquid heater for heating the reservoir liquid to a preselected temperature to enable relatively heated reservoir liquid or reservoir air to convey heat during circulation to the chambers when the external ambient temperature drops below the optimal levels.

7. The aeroponic growing system as claimed in claim 1 having a modular design to render the system modularly extendable to increase capacity in predetermined increments, the system having at least one of the components selected from the group comprising: a modular bulk liquid reservoir, locatable at least partially underground to provide a heat regulator to the liquid; a set of modular growing chambers, having a predetermined number of plant supporting formations for supporting a corresponding number of plants with the plant roots being suspended at least partially within the corresponding chambers: a set of modular liquid lines in fluid communication between the reservoir and the corresponding chambers and wherein the liquid lines extend between the chambers and the reservoir such that the liquid can be recirculated between the chambers and the reservoir; modular means for conveying liquid from the reservoir via the liquid lines to the chambers at a predetermined flow rate and pressure; a modular set of sprayers, coupled to the liquid lines in the growing chambers and potitioned to spray liquid from the reservoir at the plant roots at a predetermined droplet size and frequency for predetermined time intervals; a modular power source for powering the liquid conveying means: and a set of modular drain lines in liquid communication between the corresponding chambers and the reservoir to allow sprayed liquid to drain from the plant roots and the chambers to the liquid reservoir.

8. A method for growing plants in an aeroponic growing system, the method including the steps of: storing bulk liquid at least partially underground in a suitable reservoir, thereby at least partially regulating the heat exchange between the liquid and its surroundings; supporting at least one plant in at least one growing chamber by suspending the plant roots at least partially within the chamber; circulating the liquid in a substantially closed loop between the chamber and the reservoir; spraying liquid from the reservoir at the plant roots at a predetermined droplet size and frequency for at least one predetermined time interval; and draining sprayed liquid from the plant roots and the chamber to the liquid reservoir.

9. The method as claimed in claim 8 including the steps of: drawing external air at ambient temperature into the chamber to adjust the temperature inside the chamber towards the ambient temperature; and drawing internal air from the reservoir into the chamber to adjust the temperature inside the chamber towards the reservoir air temperature; so as to maintain optimum root-growth conditions within the chamber within predetermined ranges while minimizing energy consumption.

10. The method as claimed in claim 9 including the step of circulating the liquid and/or air flows to or from the reservoir to increase or decrease the liquid and/or air temperatures within predetermined ranges so as to maintain optimum root-growth conditions within the chamber.

11. A kit for an aeroponlc growing system, the kit including: at least one bulk liquid reservoir, locatable at least partially underground to provide a heat regulator to the Squid; at least one growing chamber, having at least one plant supporting formation for supporting at least one plant with the plant roots being suspended at least partially within the chamber; at least one liquid line for providing fluid communication between the reservoir and the chamber and wherein the liquid line Is designed and dimensioned to extend between the chamber and the reservoir in an erected format such that the liquid can be recirculated between the chamber and the reservoir; means for conveying liquid from the reservoir via the liquid line to the chamber at a predetermined flow rate and pressure; at least one sprayer, capable of being positioned in the growing chamber and coupled to the liquid line to spray liquid from the reservoir at the plant roots at a predetermined droplet size and frequency for at least one predetermined time interval; a power source for powering the liquid conveying means; and at least one drain line for providing liquid communication between the chamber and foe reservoir in the erected format to alow sprayed liquid to drain from the plant roots or foe chamber to the liquid reservoir.

12. The kit as claimed in claim 11 having a modular design to render the resulting system modularly extendable to enable increased capacity in predetermined increments, the kit preferably including at least one of the components selected from the group comprising: a modular bulk liquid reservoir, locatable at least partially underground to provide a heat regulator to the liquid; a set of modular growing chambers, having a predetermined number of plant supporting formations for supporting a corresponding number of plants with the plant roots being suspended at least partially within the corresponding chambers: a set of modular liquid lines for providing fluid communication between the reservoir and the corresponding chambers in the erected format and wherein the liquid line extends between the chambers and the reservoir such that the liquid can be recirculated between the chambers and the reservoir; means for conveying liquid from the reservoir via the liquid lines to the chambers at a predetermined flow rate and pressure; a set of modular sprayers, capable of being positioned in the growing chambers and coupled to the liquid lines to spray liquid from the reservoir at the plant roots at a predetermined droplet size and frequency for predetermined time intervals; a suitable modular power source for powering the liquid conveying means; and a set of modular drain lines for providing liquid communication between the corresponding chambers and the reservoir in the erected format to alow sprayed liquid to drain from the plant roots or the chambers to the liquid reservoir.

13. The kit as claimed in claim 12 having means for drawing external air at ambient temperature into the chamber to adjust the temperature inside the chamber towards the ambient temperature and for drawing internal air from within foe reservoir into the chamber to adjust foe temperature inside foe chamber towards the reservoir air temperature within predetermined ranges so as to maintain optimum root-growth conditions within the chamber while minimizing energy consumption.

14. The kit as claimed in claim 11 having at least one liquid heater for heating the reservoir liquid to a preselected temperature to enable relatively heated reservoir liquid or reservoir air to convey heat during circulation to the chambers when the external ambient temperature drops below the optimal levels. BLANK UPON FILING