VENTILATION SYSTEM FOR PLANT CULTIVATION

Ventilation systems for a vertical growing system for growing plants include a centrifugal fan incorporated into an air passage to compress ambient air and direct the compressed air into an elongated duct assembly.

TECHNOLOGICAL FIELD

This disclosure relates to a ventilation system for use in horticultural or agricultural operations.

BACKGROUND

Air stratification and excess water/nutrient collection are two problems associated with enclosed vertical agricultural operations. Air stratification can occur when insufficient ventilation is present, and can be especially problematic for the lower levels of racked operations where the canopy of one level of crop tends to prevent the downward circulation of air from vents or fans, which are typically present on the ceiling. Stratification is the layering of air due to density variations caused by temperature, humidity, carbon dioxide depletion etc. and is detrimental to the health of the crops being grown.

Enclosed vertical agricultural operations require that the racking systems provide a method of collecting and consolidating excess water and nutrients draining from the individual growing containers. Fluid that is not consolidated and removed from the operation can foster the growth of mold, fungus and other organisms detrimental to the health of the crops.

Current conventional solutions depend on a combination of technologies to implement drainage and de-stratification using separate trays and combinations of duct work and fans mounted below the growing trays, interfering with the positioning of lighting and potentially decreasing possible vertical density.

SUMMARY OF THE DISCLOSED SUBJECT MATTER

To address the problems in the prior art, an air box for a ventilation system for plant cultivation is provided.

A first aspect provides a system for plant cultivation, comprising a ventilation system comprising an air box comprising an air passage extending from an inlet opening in a first end of the air box to an outlet opening in a second end of the air box, the air box comprising a centrifugal fan or tangential fan disposed in the air passage configured to move air from the first end to the second end of the air box.

Embodiments include the following, alone or in any combination.

The system may comprise a centrifugal fan having a vertical axis of rotation.

The system may comprise two or more centrifugal fans, each centrifugal fan having a vertical axis of rotation.

The system may comprise a centrifugal fan having a horizontal axis of rotation.

The system wherein the centrifugal fan comprises a volute housing wherein the outlet of the volute housing is in fluid communication with the outlet opening in the second end of the air box.

The system may comprise a tangential fan having a horizontal axis of rotation, wherein the tangential fan directs air toward the outlet opening.

The outlet opening may be in fluid communication with an elongated duct assembly comprising one or more air passages, the duct assembly having a first end in fluid communication with the outlet opening, a second end opposed to the first end configured to be either closed or in fluid communication with a second duct assembly, and a plurality of orifices in the one or more air passages to distribute air out of the one or more air passages.

The plurality of orifices are configured to direct air from the duct assembly to above the duct assembly; or direct air from the duct assembly to below the duct assembly; or direct air from the duct assembly to above and below the duct assembly.

The duct assembly may be engaged to an air box comprising a first air chamber extending from an inlet opening in a first end of the air box and a second air chamber extending from an outlet opening in a second end of the air box and a centrifugal fan or a tangential fan disposed between the first air chamber and the second air chamber, the fan in fluid connectivity with the first air chamber and the second air chamber to define an air passage configured to move air from the first end to the second end of the air box.

The second air chamber is configured to fit within an air passage within the duct assembly and the outlet directs air into an air passage within the duct assembly.

The centrifugal fan has a vertical axis of rotation and an entry in fluid communication with the first air chamber; and the centrifugal fan is disposed within the second air chamber.

A second aspect provides a system for plant cultivation, comprising a ventilation system comprising an air box comprising a first air chamber extending from an inlet opening in a first end of the air box and a second air chamber extending from an outlet opening in a second end of the air box and a centrifugal fan or a tangential fan disposed between the first air chamber and the second air chamber, the fan in fluid connectivity with the first air chamber and the second air chamber to define an air passage configured to move air from the first end to the second end of the air box.

Embodiments of this aspect include the following, alone or in any combination.

The air box is configured to engage a duct assembly to draw ambient air into the air box through the inlet opening and direct compressed air through the outlet opening into the duct assembly.

The outlet opening is in fluid communication with an elongated duct assembly comprising one or more air passages, the duct assembly having a first end in fluid communication with the outlet opening, a second end opposed to the first end configured to be either closed or in fluid communication with a second duct assembly, and a plurality of orifices in the one or more air passages to distribute air out of the one or more air passages.

The second air chamber is configured to fit within an air passage within the duct assembly and the outlet directs air into an air passage within the duct assembly.

The centrifugal fan has a vertical axis of rotation and an entry in fluid communication with the first air chamber.

The centrifugal fan is disposed within the second air chamber.

The plurality of orifices are configured to direct air from the duct assembly to above the duct assembly; or direct air from the duct assembly to below the duct assembly; or direct air from the duct assembly to above and below the duct assembly.

The system may further comprise a tray comprising opposed sides and opposed ends defining a perimeter of the tray, and a raised region disposed within the perimeter of the tray.

The raised region of the tray may comprises a plurality of alternating parallel ridges disposed between the side walls and a plurality of valleys formed between adjacent ridges of the plurality of ridges, wherein one or more of the plurality of valleys are in fluid communication with a gutter; and optionally one or more of a plurality of holes in one or more of the plurality of ridges in fluid communication with the plurality of orifices in the top panel of the duct assembly to direct air from the duct assembly to above the tray.

DETAILED DESCRIPTION

Disclosed herein is a compact pressurized air supply (CPAS) that provides specially pressurized air to a rack-mounted air distribution system for ventilation and de-stratification.

FIG.1Ashows a schematic perspective view of a CPAS air box, according to an embodiment of the disclosed subject matter. The air box1comprises a first end11with an inlet opening, first and second sides12and13, bottom face14and top face15. In embodiments, the shape of the air box is not limited as long as it is configured such that the inlet of the air box is larger in area than the outlet of the air box as discussed below. In the embodiment shown, the top face comprises a first horizontal portion and a second sloping portion that intersects with the second end16, but this is not limiting. Other embodiments may include the top face being curved to transition smoothly from the horizontal portion to the sloping portion. Similarly, the sides and front face may be constructed as planar surfaces, or their junction may be curved so that the front opening curves around to a portion of the sides to provide a larger inlet opening. Opposite the first end11is a second end16with an outlet opening. Sides12and13, bottom face14and top face15define boundaries of an air passage extending from the inlet opening in the first end of the air box to the outlet opening in the second end of the air box. Disposed in the air passage is one or more centrifugal fans20(shown in close-up view inFIG.1B) mounted on the bottom face14. Two centrifugal fans are in the embodiment shown inFIG.1A, but that is not limiting. In the non-limiting embodiment depicted inFIG.1A, the CPAS has an overall shape wherein the inlet opening has a greater area than the outlet opening. The inlet opening may be generally rectangular, with a horizontal dimension greater than a vertical dimension. As can be seen, the inlet opening comprises substantially (greater than 90%) of the first end of the air box surrounded by a frame defined by the edges of the sides, bottom and top of the air box. In the embodiment shown, the outlet opening has a horizontal dimension greater than a vertical dimension. The first end of the air box has a vertical dimension greater than a vertical dimension of the second end of the air box. These aspects are not limiting. In the CPAS, ambient air enters the inlet opening in a generally horizontal direction and air exits the outlet opening in a generally horizontal direction.

FIG.1Bshows a centrifugal fan useful in the CPAS embodiment ofFIG.1A. For ease of presentation, housing or shroud19around the fan is not shown. The centrifugal fan20comprises a drum-shaped body21with an open interior in fluid communication with a plurality of openings between a plurality of impeller vanes22. The impeller vanes may be straight radial vanes, or curved vanes that can be backward-curved or forward-curved in relation to the direction of rotation of the drum body21. Notably, the fan(s) may comprise backward-curved vanes. Impeller intake bell24defines an axial opening in fluid communication with the interior of the drum body21. Air is drawn in through the center of the impeller intake bell23and expelled out the plurality of openings, as shown by the arrows, directly into the outlet opening in the second end of the air passage. In the embodiment of the CPAS1shown inFIG.1A, the centrifugal fans have a vertical axis of rotation. An electric motor24turns the fan with a sufficient RPM to compress ambient air entering the inlet of the air box and drive it out of the outlet at increased pressure and velocity compared to the ambient air.

In embodiments with two or more centrifugal fans20, the fans may rotate in the same direction (both clockwise or both counterclockwise) or in opposite directions (one clockwise and one counterclockwise). Counter-rotating fans may be notable to direct air flow toward the center of the outlet of the air box.

The CPAS housing also integrates a removable intake filter located parallel to the housing inlet. The placement of this filter allows for a large surface area and a decrease in accumulating debris.FIG.1Cshows the CPAS1with a filter17partially installed proximate to the first end11. Flanges on the sides12,13and bottom14may define slots that a panel filter17can be slid into from above to cover the inlet opening in the first end11of the air box. Retainer strip15aholds the top end of the filter in place and may optionally held in place by mechanical fasteners such as screws, thumb screws, wing screws, clips, etc., or by magnet coupling(s). A filter panel17is shown proximate to the first end11. Filter17is substantially the same size as the inlet opening so that ambient air entering the inlet is filtered. The filter may be constructed of a washable foam or HEPA medium and is designed to remove particulates in the intake air stream. Alternatively or additively, a disposable filter may be used.

FIG.1Dshows the CPAS air box1ofFIG.1Afrom the opposite side. Top face13is shown as transparent to allow visualization of the interior of the CPAS air box1. Outlet opening in the second end is16defined by the edges of sides12,13, bottom face14and top face15. Comparison of the outlet opening in second end16to the inlet opening in the first end11shows that the inlet opening has a larger area than the outlet opening.

Optional vertical divider18may provide strength and/or rigidity to the air box. It may also help direct air from the inlet into one or the other of the two centrifugal fans20shown in this embodiment. Internal shroud19wraps around the fan20to block air from exiting the fan toward the inlet and direct it toward the outlet opening in second end16.

The housing may include one or more integrated electrical junction boxes30, which can serve as connection points to external motor supply wiring, as well as low voltage speed control signals. The housing may also include wired or wireless networking capability to connect to sensor or control networks. Information such as fan speed, outlet pressure, inlet pressure, fan temperature, intake air temperature, intake air humidity, etc. may be transmitted on the network.

FIGS.1E,1F and1Gshow another embodiment of the ventilation system in which the top15and bottom14have curved front edges so that front face11curves into the sides12and13of the air box housing. This provides for a greater opening for the air inlet. It also reduces the volume of the airbox that intrudes into the area around a growing rack and the curved surfaces improve safety of personnel working around the air box by eliminating hard sharp edges of the air box. The view inFIG.1Ealso shows divider18and shrouds19inside the air box.FIG.1Fshows another embodiment of the centrifugal fan shown in Fig. B.FIG.1Gshows the airbox with a flexible filter17disposed over a portion of front face11and wrapping around onto side12. Another filter17is deleted to show a lightweight flexible frame17athat extends across front face11from its junction with divider18to its junction with side13. The bottom of the framework may be supported by the shroud19. A similar framework extending from divider18to a junction with side12is not visible behind filter17.

FIGS.2A and2Bshow side and front views of a conventional prior art ventilation system for a vertical growing system, respectively. As seen inFIG.2A, conventional solutions use a combination of externally mounted fans, filters and ductwork to direct air into a rack-mounted ventilation and de-stratification system. These systems200include an air box or housing204, an externally mounted fan203(depending on the location of the filter) and/or a filter202located either before or after the fan. The fan is typically an axial tube fan (“can fan”) that is mounted vertically on an air box. The air box is then coupled to the ventilation ductwork that extends horizontally along the growing rack. The primary function of the air box204is to turn the airflow, which is supplied in an upward or downward direction, to match the horizontal input of the rack mounted ductwork. In the example200shown, air enters the top of the system at arrow201and is turned by the air box to a horizontal direction, as indicated by the arrow to exit the ventilation system at arrow205.

In some designs the filter is located in a filter housing, which also serves to turn the air from the input to output. In these designs the fan is located externally to the housing, which contains a filter or series of filters. Air is directed into the housing by the externally mounted fan, which may or may not include a pre-filter. The primary drawback to all of these external fan designs is the need to immediately turn the airflow exiting the fan up to 90 degrees in a very tight space. This turn is necessitated by the tight clearance usually found on the back of CEA racks, which would not allow a large air box or inline axial fan. This tight turn leads to significant pressure losses and unnecessary turbulence in the ductwork. The pressure loss is exacerbated in designs incorporating a compact filter housing directly after the fan, as it is very difficult to provide sufficient filter media area. This leads to very high velocities through the filter, high pressure drop and frequent loading of the filter.

FIGS.3A and3Bshows side and front views of a CPAS ventilation system as described herein. The CPAS design addresses the issues of prior art conventional ventilation systems by integrating specially designed fans directly into the air box. By incorporating specific fan designs that have an inherent 90 degree direction change input to output, the air box or housing no longer needs to perform this function. Centrifugal impellers integrated into the air passage inside the air box eliminate the need for a turning duct to change the direction of the air exiting a conventional can fan (axial fan). This leads to a much more compact and efficient design. Air is drawn into the housing at the inlet opening in face11parallel to the output in face16, and no direction change occurs relative to the housing intake as air exits the fans (arrow301). ComparingFIGS.2A-2BwithFIGS.3A-3B, a CPAS configured to deliver the same amount of air to a duct in fluid communication with the outlet as a conventional system is more compact and simpler in construction. It is notable that the housing is under vacuum in the CPAS design, versus being under pressure for all conventional systems.

In the embodiments shown inFIGS.1A-1D, shown in schematic cross-section inFIG.4, centrifugal impeller(s)20are used in which the axis of rotation is perpendicular to the horizontal plane of rack-mounted ducting. In this design, the rack-mounted ducting lies along a hypothetical X-Y plane, with the X axis lying along the length of the duct and the Y axis along the width, with airflow in the X direction. The impeller rotation is around the Z-axis. Air is drawn horizontally into CPAS housing401through the opening in front face11, through filter17and vertically into the impeller along the Z axis and then exits tangentially through the outlet in a second end16into the ductwork (not shown), achieving the required direction change and increase in pressure without the need for additional bulky turning features in the air box.

In other embodiments, the centrifugal fan may alternatively rotate about the Y-axis, drawing air into the fan along the same Y-axis and discharging it along the X axis into the duct. In an embodiment, shown in schematic cross-section inFIG.5A, this may comprise a centrifugal blower design520with a scroll or volute housing525. A representative volute casing is shown inFIG.5B. Air enters the air box501horizontally along the X-axis at11, passes through filter17and makes a horizontal turn into intake521to the center of the impeller (not shown) rotating about the Y-axis and exits the casing525in the X-direction at16. In this embodiment components of the device may be similar to those described for the embodiment described inFIGS.1A-1D, except for the configuration of the fan inside the air box. In this embodiment, one, two or more housed fan may be configured in the air box, depending on the desired dimensions of the system.

Another embodiment uses a tangential or crossflow type fan, where the fan is again rotating about the Y-axis, but in this case air would be drawn into the impeller along the Z axis as in the first design. The impeller in this case would extend along the width of the outlet, providing consistent flow along the width of the duct. In an embodiment, shown in schematic cross-section inFIG.6A, this may comprise a tangential or cross flow fan620with a shroud625. A representative cross flow fan is shown inFIG.6B. Air enters the air box601horizontally along the X-axis at11, passes through filter17and enters the fan620through the open top of shroud625to the impeller rotating about the Y-axis and exits the shroud625tangentially in the X-direction at15. In this embodiment, components of the device may be similar to those described for the embodiment described inFIGS.1A-1D, except for the configuration of the fan inside the air box.

The housing of any embodiment described herein may also be capable of including a component to amend air before it exits the air passage such as a heater, cooler, dehumidifier, humidifier, carbon dioxide (CO2) injector, ozone injector, ultraviolet light emitter, or combinations thereof. Notably, the system may include UV antimicrobial lighting on the intake side, which benefits from the lower flow velocities present in the housing. Lower flow velocities increase the time of UV exposure and increase the effectiveness of such a system.

The housing is designed to be used in conjunction with a racking system and fluidly coupled to rack mounted distribution ducting.FIG.7Ashows the front of the CPAS mounted on a racking system700comprising upright members701, shelving members702and diagonal braces703. Upright members preferably comprise a plurality of holes or openings705that allow components to be mounted thereon, using fasteners such as bolts or clips. The plurality of holes705allows a user to selectively position shelves702and the CPAS1at desirable levels or heights to grow plants in a vertical growing system. The racking system may comprise a plurality of shelving members702. Brackets710on each side of the CPAS housing allow for its attachment to the racking system.FIG.7Bshows a side view of the CPAS1attached to the rack700and a duct system720that is in fluid communication with the outlet of the CPAS. The duct system comprises one or more elongate duct members (two are shown:721and722). As shown by the arrows, ambient air at the left of the figure is drawn into the inlet11of the CPAS, pressurized and then driven out the outlet16into the duct system. Each duct member may comprise a plurality of orifices (not shown) that distributes air from the duct above and/or below the duct to plants (not shown) supported by the growing system.

In an embodiment, the CPAS outlet opening is in fluid communication with an elongated duct assembly comprising one or more air passages, the duct assembly having a first end in fluid communication with the outlet opening, a second end opposed to the first end configured to be either closed or in fluid communication with a second duct assembly member, and a plurality of orifices in the one or more air passages to distribute air out of the one or more air passages. Notably, the duct system comprises a plurality of orifices configured to direct air from the duct assembly to above the duct assembly; or direct air from the duct assembly to below the duct assembly; or direct air from the duct assembly to above and below the duct assembly.

FIG.7Cshows a top perspective view of an exemplary embodiment of a duct assembly. In the embodiment shown inFIG.7C, a representative duct assembly720is constructed of flat top panels723that form the top of the duct assembly720, flat bottom panels724that form the bottom of the duct assembly720, a center support member26and side support members27aand27b. Flat panels723and724may be made from polymer, composite or metal. Preferably the duct assembly panels can be made of plastics such as PVC, ABS, ASA, polycarbonate, polyethylene, etc. Notably, expanded PVC can be used due to its low cost and stiffness.FIG.7Cshows that the top panels723may optionally comprise holes725to provide air flow above the duct. In embodiments, the holes are configured to be in fluid communication with holes in a tray described further below. In other embodiments (not shown), the top panels723do not have holes and air would not be delivered above the duct.

As shown inFIG.7D, in some embodiments the bottoms of the ducts720aand720bmay comprise a plurality of orifices726in the bottom panels724to allow air to be distributed from the CPAS ventilation system through the ducts and onto plants below the tray system in a vertical growing system. The orifices may be round, oval shaped, rectangular, slotted etc. In other embodiments the bottom panels724do not comprise orifices726and air cannot exit from the bottom of ducts720aand720b. The distribution of orifices726in bottom panels724may be based on the desired flow capacity of the blowing system.

In the embodiment illustrated in the Figures, the edges of the top and bottom duct panels723and724are attached to the center support member728and side support members727aand727bpreferably by insertion into slots at the top and bottom of the center and side support members. To provide adequate support for a tray placed over the duct (see below) and plant containers thereon, the support members may be typically fabricated from a variety of materials such as stainless steel, aluminum, alloys or carbon composites, etc. Notably, the support members are configured to be elongate with a consistent cross-section along their length, allowing for their fabrication as extrusions. Preferably, the center and side support members are aluminum extrusions.

The top panels723and bottom panels724are preferably releasably engaged with the support members728,727aand727bso that the duct assembly can be disassembled to interchange top panels723and/or bottom panels724to modify the air distribution out of the ducts720aand720bto direct air above the tray system, below the tray system or both above and below the tray system. Disassembly also allows for easy cleaning and/or compact storage of the components of the duct assembly720.

Optionally, as shown inFIG.7D, the support members728,727aand727bmay also incorporate a feature (in the embodiments shown a “t-slot”)729along their bottom surfaces to allow the installation of hooks or fittings to hold lighting and/or other equipment. Embodiments include those wherein the central support member728comprises a t-slot extending the length of the central support member. Embodiments include those wherein the first and second elongate side support members727aand727beach comprises a t-slot extending the length of their respective bottoms. The t-slots729can also serve as a fastening feature between duct sections with the use of a connector that fits within the slot and bears between the inside of the slot and the top on each support member section. The t-slots729may also be used to attach the duct assembly20to horizontal support members (e.g. shelf702) on a rack system700.

FIG.7Eshows duct members721and722abutted end-to-end, with top panels723removed. This Figure shows the duct assembly with a first open end731configured to engage with the outlet end of a CPAS described above to receive pressurized air into the duct. The second end732is shown as closed so that air has to exit the duct via openings726in bottom panels724. In this view, joints736between bottom panels724and joints737between support members are shown as staggered, which may provide additional stability to duct assembly that comprises two or more duct members720.

In embodiments, the system may further comprises one or more trays to support plants and growing medium above the ducts.FIG.8Ashows two trays801aand801bdisposed over the duct members721and722(not shown, seeFIG.7B). As described above, openings726(when present) in the bottom of the duct assembly allow fresh air to exit the duct out the bottom to provide air to the top of the leaf canopy of plants below the duct assembly. Openings725(when present) in top panels align with ridges810to allow air to exit from the top of the duct assembly into ridges810and out holes811(seeFIG.8B) to provide fresh air below the leaf canopy of plants disposed on the trays.

A top perspective view of an embodiment of a representative tray801is shown inFIG.8B. The tray comprises opposed side walls802and opposed ends803defining a perimeter of the tray, and a raised region804disposed within the perimeter of the tray. In embodiments, the side walls802of the tray may extend below the raised region to support the raised region above the duct assembly. The side walls may also provide support to the tray when it is not disposed on the duct assembly. Preferably, the raised region of the tray comprises a plurality of alternating parallel ridges805disposed between the side walls and a plurality of valleys806formed between adjacent ridges of the plurality of ridges, wherein one or more of the plurality of valleys are in fluid communication with a gutter807; and optionally one or more of a plurality of holes811in one or more of the plurality of ridges. In the embodiment shown, a subset of the ridges comprises a plurality of ridges810that comprise holes811. In preferred embodiments, the ridges810have top surfaces higher than the top surfaces of the ridges805to prevent water from above to pass through the holes811. The plurality of holes811, when present, are in fluid communication with the plurality of orifices in the top panel(s)724of the duct assembly720to direct air from the duct assembly to above the tray801.

In the embodiment shown, the plurality of alternating parallel ridges805comprise top surfaces defining a level plane for supporting one or more individual growing containers for containing growth medium and plants, and the plurality of valleys slope downward from a peak to the gutter proximate to the perimeter of the tray, the one or more of the plurality of valleys are in fluid communication with the gutter for channeling fluid collected into the gutter. Notably, the gutter may be configured to be in fluid communication with a fluid drainage system.

Typically, the ducting720will be laid down first with the tray801positioned or disposed over the top of the duct720. The duct assembly720is designed to nest under the tray801, which preferably has sloping valleys806. In these embodiments, the upper surfaces of the duct assembly720may be angled to accommodate the draining feature of valleys806of the tray801, which are sloped to collect and concentrate the excess water and nutrients. Accordingly, in the embodiment of the duct720shown inFIG.7C, the cross-section of the two ducts720aand720bof the duct assembly720may generally be trapezoidal with a flat bottom and sides and an angled top.

In some embodiments, the bottom surface of the raised region of the tray comprises the top panel of the duct assembly. In an embodiment shown inFIG.8C, the underside of a tray801is shown. Fitting815, such as a hose barb, is disposed on the bottom of the tray to allow fluid communication from the gutter to a drainage system via a hose or tubing (not shown) attached to the fitting815. Optionally, thin adhesive backed panels820can be added to the underside of the tray to improve performance by reducing duct turbulence inside the duct. The panels820may be adhesively attached to the bottom surface of the valleys in the raised portion of the tray. It can be seen that panels820may cover a significant part of the underside of the tray. Notably, the panels820do not cover the bottom of the ridges810, allowing air to pass from the duct into the ridges810and out holes911in tray801. In other embodiments not shown, the panels820cover the bottom of the ridges810, preventing air from passing from the duct into the ridges810and out holes911in tray801.

FIG.8Dshows a perspective view of a cutaway of tray801, showing the relative geometry among the ridges805, valleys806and gutter807. The valleys806slope toward the gutter807so that water on the raised region of the tray flows to the gutter. Panels820are attached to the bottom of the valleys.

FIG.9Ashows an exploded perspective view of an embodiment of the ventilation system using trays801wherein their bottom surfaces comprise the top panels of the duct system920.FIG.9Bshows a top view of an embodiment of the ventilation system wherein one tray801is removed to show the bottom of the duct system920. Because the trays801comprise the top of the duct system920, the bottom of the duct system920can be configured as a trough, comprising side members922aand922band bottom panels924. Optionally, as shown in this embodiment, a center member923may be included. Bottom panels924are disposed between the center member923(if present) and respective side members922aand922b. Bottom panels924may optionally comprise a plurality of openings similar to openings724shown inFIG.7Dto distribute air below the duct. The bottoms of the side and center members922a,922band/or923may comprise a t-slot similar to t-slot729along the bottom surface to provide for the installation of hooks or fittings to hold lighting and/or other equipment, a fastening feature between duct sections, and/or to attach the duct assembly920to horizontal support members (e.g. shelf702) on a rack system700. Small panels925are configured to be disposed at the tops of the center member922a,922band/or923to provide an enclosed duct segment in fluid communication with the outlet of the CPAS unit1. Additional small panels926are configured to be disposed at the tops of the side and center member922a,922band/or923to provide an enclosed duct segment between the ends of the trays801. Panels925and926may be configured to rest on, and optionally attach to, the tops of the tops of the side and center members922a,922band/or923. Alternatively, Panels925and926may be configured to engage slots or recesses in the side and center members922a,922band/or923.

FIG.9Cshows a detail of the embodiment shown inFIGS.9A and9B. Tray801is disposed above side members922b. Two side members922bare joined by a connector plate932disposed in a groove930in the top of the side members922b. Plate932is fastened to the side members922bwith screws933. Panel926is engaged proximate to the top of the side panels922bso that it overlaps the seam935between the side members922b, thereby forming an enclosed duct portion below adjacent trays801. An elastomeric gasket or weatherstrip (not shown) may be disposed in the groove930to provide an air-tight junction between the top of side member922band the bottom of tray801to provide an enclosed duct.

In embodiments, side members922a,922band center member923, when present, are strong enough to support trays and plants thereon without using a continuous shelf702in a vertical rack system700. Optionally, horizontal cross members between vertical members of the rack system can be used to support the duct system.

In additional embodiments of a compact pressurized air supply (CPAS), the impeller is integrated within the duct assembly. In these embodiments, the inlet portion of the air box, the first end of the air passage, is mounted below the duct and the impeller of a centrifugal fan extends into the first end of the duct member. The outlet of the air box, the second end of the air passage, is contained within the first end of the duct member. Air enters the inlet horizontally, and is driven down the duct horizontally toward the second end of the duct member by the centrifugal fan. These embodiments are very compact and require little to no end clearance for a ventilation system connected to elongated ducts for use in a vertical growing system where there is no clearance for a fan box extending beyond the ends of the tracks.

In these additional embodiments, the ventilation system comprises an air box comprising a first air chamber extending from an inlet opening in a first end of the air box and a second air chamber extending from an outlet opening in a second end of the air box and a centrifugal fan or a tangential fan disposed between the first air chamber and the second air chamber, the fan in fluid connectivity with the first air chamber and the second air chamber to define an air passage configured to move air from the first end to the second end of the air box.

FIGS.10A-Fshow aspects of an embodiment of a CPAS system1000with the fan integrated into the duct assembly.FIG.10Ashows an intake housing1010for this embodiment. The housing1010comprises a plate1011with an opening1012defined by a raised rim1013. The opening1012and rim1013are configured to engage the inlet of a centrifugal fan (not shown, seeFIG.10B) so that the opening1012is in fluid communication with the interior of the centrifugal fan. The housing1010defines a first air chamber in this embodiment. Edges1011aand1011bof plate1011are configured to engage shelves and/or slots in side members922aor922band center member923of a duct system920(not shown, seeFIG.10B). Other edges1011cand1011dare also shown. A scoop-shaped shroud1014is disposed below plate1011to define a cavity or first air chamber inside the housing1010. Shroud1014comprises opening1016to provide an air inlet into the housing1010. Filter1017disposed in the opening1016provides for removal of particulates from the ambient air entering the cavity through the opening1016. Plate1011and shroud1014define the boundaries of an air passage from opening1016to opening1012, comprising the first end of the air box as described herein.

The second end or second air chamber of the air box of CPAS1000is shown inFIG.10Bin perspective view. Plate1011is engaged to lower shelf952bon side member922band a lower shelf953on center member923. Thus plate1011serves as a bottom panel for the duct assembly in the region of the air passage. Centrifugal fan1020is disposed above plate1011over opening1012(not visible in this view) and below top plate1030. The second air chamber of the second end of the air box is defined by plates1011and1030, side member922band center member923. The open side of the second air chamber provides an outlet of the air box that is directed into and is in fluid communication with the remainder of the duct assembly as described further below.

FIG.10Cshows a perspective view of two air boxes of this embodiment disposed side-by-side in a duct assembly920. Plates1011are engaged to lower shelves952aand952b(not visible) on side members922aand922b, respectively, and lower shelves953on center member923. Centrifugal fans1020are disposed above plate1011and below top plates1030. Two shrouds1014(one is not visible) are disposed below the plates1011.

Not shown inFIGS.10B and10Care bottom panels924disposed between the center member923and either922aor922b, that provide the bottom of the duct assembly beyond the air box region.

FIG.10Dshows another perspective view of two air boxes of this embodiment disposed side-by-side in a first end of a duct assembly920. Two shrouds1014are disposed below the duct assembly. Each shroud comprises an inlet1016with a filter1017disposed therein. Tray801is disposed to define the top of the duct assembly. A portion of side member922bis seen projecting out from under tray801. Plate1040is attached to the ends of the side and center members to close the first end of the duct assembly so that air enters the duct assembly via opening1016and is driven through the duct assembly away from the first end.

FIG.10Eshows the embodiment of the CPAS1000engaged to the duct and tray system from below. Shroud1014is shown as transparent to allow visualization of components within the CPAS. As shown by the arrows, air enters the CPAS via opening1016, through filter1017into the interior of the shroud1014, where it is drawn into the inlet of centrifugal fan1020by the plurality of vanes1021rotating about the axis of rotation of the fan1020. Bottom panel924abuts panel1011to close the bottom of the duct assembly.

FIG.10Fshows the embodiment of the CPAS from above. Tray801is shown as transparent to allow visualization of components within the CPAS. As shown by the arrows, air enters the CPAS horizontally via opening1016, through filter1017into the interior of the shroud1014, where it drawn into the inlet1021of centrifugal fan1020by the plurality of vanes1022rotating about the axis of rotation of the fan1020. Pressurized air is driven into the duct by the movement of vanes1022. A portion the air is driven out of holes811in ridge810, while the majority of pressurized air moves horizontally further down the duct. Gasket830is disposed between side member922aand tray801. Optionally, an internal shroud1050(shown in dashed outline) may be disposed around a portion of the centrifugal fan1020to facilitate directing air down the duct.

The embodiment of the CPAS1000shown inFIGS.10A-10Fis designed to draw air horizontally into the duct assembly from the end in the X-direction, parallel to the orientation of the duct assembly (end-entry). In alternate embodiments, the CPAS1000may be configured to draw air into the duct from the side, the Y-direction. This side-entry configuration can be achieved by turning the shroud101490 degrees relative to that shown in the figures. All other components described remain essentially the same as previously described. For example, if plates1011and1030are square, instead of engaging edges1011aand1011bwith the lower shelves0953and952aor952bon the center and side members, edge1011ccan be engaged to shelf952aor952band edge1011ccan be engaged to shelf953. Alternatively, shroud1014may be configured so it is not attached to plate1011, but instead comprises an opening coaxial to opening1012that is pivotably engaged to the rim1012so that it can swivel between an end-entry and a side-entry configuration. Side-entry CPAS units may be useful for pressuring the center of a duct assembly. Because the CPAS1000is configured to fit within the footprint of the duct and tray assembly, one or more CPAS1000units can be deployed in a single level of a vertical growing rack without extending into the space around the growing rack, impeding movement around the growing rack. For example, in a long duct run, the pressure drops as the air exits the duct above and/or below the duct. Pressure inside the duct can be increased by using an end-entry CPAS at each end of the duct run and one or more side entry CPAS units along the duct run between the duct ends. The small volume of the CPAS unit1000allows great flexibility in designing a growing system to accommodate a variety of configurations.

FIG.11shows a schematic view of an alternative embodiment1100of a CPAS system wherein a portion of the fan extends into the duct assembly and air enters the housing from the side relative to the orientation of the elongated duct, i.e. along the Y-axis. This embodiment is a variation of a volute fan described above in relation toFIGS.5A and5B. In this embodiment, housing1101is disposed below a duct1120and defines a first air chamber. Housing1101has an inlet opening1102with a filter (not shown) disposed therein to filter ambient air entering the housing1101through opening1102. A centrifugal fan1103with its axis of rotation1104lying along the Y-axis is disposed near the top of the housing so its lower portion, including its inlet1105, is within the housing1101. The upper portion of the air box, including its exit1110, is disposed within the duct assembly1120and defines the second air chamber. Shroud1111extends into the duct1220from the housing1101to direct airflow around the fan1103to exit the fan through exit1110into duct1120. In the embodiment shown, a single opening1102allows air to be drawn into the center of fan1103at one end. In other embodiments, the housing1101may have two openings1102so that air can be drawn into the center of fan1103at both ends. As described above in relation to CPAS unit1000, the CPAS unit1100is configured to fit within the footprint of the duct and tray assembly without extending into the space around the growing rack, impeding movement around the growing rack.

FIG.12shows a schematic cross-section view of an alternative embodiment1200of a CPAS system wherein a portion of the fan extends into the duct assembly. This embodiment is a variation of a tangential fan described above in relation toFIGS.6A and6B. In this embodiment, housing1201is disposed below a duct1220and defines a first air chamber for this embodiment. Housing1201has an inlet opening1202with a filter1217disposed therein to filter ambient air entering the housing1201through opening1202. A tangential fan1203with its axis of rotation1204lying along the Y-axis is disposed near the top of the housing so its lower portion is within the housing and its upper portion is disposed within the duct assembly1220. A slot around the tangential fan allows air to pass through the housing1201into duct1220. Shroud1210extends into the duct1220to direct airflow around the fan1203to exit the fan tangentially through exit1211into duct1220. The upper portion of housing1201and shroud1210define a second air chamber for this embodiment. As described above in relation to CPAS unit1000, the CPAS unit1200is configured to fit within the footprint of the duct and tray assembly without extending into the space around the growing rack, impeding movement around the growing rack.

FIGS.13A-Fshow aspects of another embodiment of a CPAS system1300with the fan integrated into the duct assembly.FIG.13Ashows a top perspective view of this embodiment. The lower housing1310comprises a plate1311with an opening1312configured to engage the inlet of a centrifugal fan1330so that the opening1012is in fluid communication with the interior of the centrifugal fan. The housing1310defines a first air chamber in this embodiment. Edges1311aand1311bof plate1311are configured to engage shelves and/or slots in side members922aor922band center member923of a duct system920(not shown, seeFIG.10Bfor analogous connections). Sides1313and1314and plate1311define part of the boundary of a first air chamber1315. As seen in bottom perspective view inFIG.13B, curved framework members1316engaged below plate1311and between sides1313and1314combine with1311,1313and1314to define a cavity or first air chamber inside the housing1310. The open area1318among these parts provide an air inlet into the housing1310. This air inlet is significantly larger than the inlet1016of CPAS unit1100, allowing a greater amount of ambient air to be drawn into the air box and compressed by the fan1330to be directed into a duct assembly connected to the air box.

Returning toFIG.13A, a second air chamber1320is defined by the top of plate1311, top plate1321and sides1322and1323. Fan1330is disposed within the second air chamber1320. An outlet1324is bounded by1311,1321,1322and1323and is configured to direct air into duct system920. A shroud1325is shown within second air chamber1320to help direct air toward the duct system920. Back plate1340is engaged to the second air chamber to close that end. Back plate1340has end1341configured to engage a side support member of the duct system920.

FIG.13Cshows a flexible filter1317disposed in the opening1318that provides for removal of particulates from the ambient air entering the first air chamber1315through the opening1318. Filter1317may be slid into groove or channel1352on side1312and a corresponding groove or channel (not visible) on side1313. Filter1317may comprise stiffening ribs1317a.

FIG.13Dshows a top or plan view of the unit1300, wherein top plate1321is shown as transparent to show objects below it. The shroud1325curves behind the fan1330so that air is directed toward the duct assembly920(not shown).

FIG.13Eshows an end view of the unit1300. It can be seen that the top of end plate1340slopes slightly downward toward the right so that the upper (second) air chamber matches the trapezoidal cross-section of an air passage in duct assembly920(not shown) disposed below the valleys of tray801(also not shown, seeFIG.14A).

FIG.13Fshows a cross section of the unit1300.

FIG.14Ashows two units1300disposed at the end of a duct system920(not shown). The end plates1340L and1340R are shown sloping downward from a center point below the center point of tray801to match the trapezoidal cross-sections of air passages in duct assembly920(not shown) disposed below the valleys of tray801.

FIG.14Bshows a bottom view of two1300units disposed at the end of a duct system920under tray801. One1300unit is disposed between side support922aand center support923and a second1300unit is disposed between side support922band center support923. Bottom panels924are disposed between center support923and side supports922aor922b. In the embodiment shown, bottom panels do not have openings so air is directed through the ventilation system1300down the duct system920and exits above the tray801.

It can be appreciated that the lower housing1310comprising lower air chamber1315in embodiment1300can be adapted to replace the lower housing1101in embodiment1100and the lower housing1201in embodiment1200provide a first air chamber for those embodiments.

In the CPAS units shown inFIGS.10A-10F,11,12and13A-F and14A-B, the inlet is disposed in a housing disposed below the duct assembly. Alternatively, the inlets can be disposed above the duct assembly. These embodiments may be useful for installation at the lowest growing level of a vertical growing system, where space below the lowest level is limited or has an increased level of particulates relative to space above the lowest growing level.

Embodiments

A first embodiment provides a system for plant cultivation, comprising: a ventilation system comprising an air box comprising an air passage extending from an inlet opening in a first end of the air box to an outlet opening in a second end of the air box, the air box comprising a filter disposed in the air passage proximate to the first end; and a centrifugal fan or tangential fan disposed in the air passage configured to move air from the first end to the second end of the air box.

Embodiments of the system comprise the following embodiments, alone or in any combination.

The system wherein the inlet opening has a greater area than the outlet opening.

The system wherein the inlet opening is generally rectangular, with a horizontal dimension greater than a vertical dimension.

The system wherein the outlet opening has a horizontal dimension greater than a vertical dimension.

The system wherein the first end of the air box has a vertical dimension greater than a vertical dimension of the second end of the air box.

The system wherein ambient air enters the inlet opening in a generally horizontal direction and air exits the outlet opening in a generally horizontal direction.

The system comprising a centrifugal fan having a vertical axis of rotation.

The system wherein the centrifugal fan comprises a plurality of curved impeller vanes.

The system comprising two or more centrifugal fans, each centrifugal fan having a vertical axis of rotation.

The system wherein each centrifugal fan comprises a plurality of curved impeller vanes.

The system comprising a centrifugal fan having a horizontal axis of rotation.

The system wherein the centrifugal fan comprises a volute housing wherein the outlet of the volute housing is in fluid communication with the outlet opening in the second end of the air box.

The system comprising a tangential fan having a horizontal axis of rotation, wherein the tangential fan directs air toward the outlet opening.

The system wherein the ventilation system further comprises a component to amend air before it exits the air passage.

The system wherein the component to amend air comprises a heater, cooler, dehumidifier, humidifier, carbon dioxide (CO2) injector, ozone injector, ultraviolet light emitter, or combinations thereof.

The system wherein the air box is configured to attach to a rack system for supporting cultivated plants.

The system wherein the outlet opening is in fluid communication with an elongated duct assembly comprising one or more air passages, the duct assembly having a first end in fluid communication with the outlet opening, a second end opposed to the first end configured to be either closed or in fluid communication with a second duct assembly, and a plurality of orifices in the one or more air passages to distribute air out of the one or more air passages.

The system wherein the plurality of orifices are configured to direct air from the duct assembly to above the duct assembly; or direct air from the duct assembly to below the duct assembly; or direct air from the duct assembly to above and below the duct assembly.

The system wherein the one or more air passages in the duct assembly are each defined by an elongated bottom panel; a first elongated side member and a second elongated side member, each side member having a bottom end and a top end, wherein the bottom ends of the first and side members are engaged to opposed sides of the elongated bottom panel; and an elongated top panel with opposed first and second sides, the first side configured to engage the top end of the first side member and the second side configured to engage the top end of the second side member.

The system wherein the bottom panel comprises a plurality of orifices to direct air from the duct assembly to below the duct assembly.

The system wherein the top panel comprises a plurality of orifices to direct air from the duct assembly to above the duct assembly.

The system wherein the bottom panel comprises a plurality of orifices to direct air from the duct assembly to below the duct assembly and the top panel comprises a plurality of orifices to direct air from the duct assembly to above the duct assembly.

The system further comprising a tray comprising opposed side walls and opposed ends defining a perimeter of the tray, and a raised region disposed within the perimeter of the tray.

The system wherein the raised region of the tray comprises: a plurality of alternating parallel ridges disposed between the side walls and a plurality of valleys formed between adjacent ridges of the plurality of ridges, wherein one or more of the plurality of valleys are in fluid communication with a gutter; and optionally one or more of a plurality of holes in one or more of the plurality of ridges.

The system wherein the plurality of holes are present and are in fluid communication with the plurality of orifices in the top panel of the duct assembly to direct air from the duct assembly to above the tray.

The system wherein the bottom surface of the raised region of the tray comprises the top panel of the duct assembly.

The system wherein the plurality of alternating parallel ridges comprise top surfaces defining a level plane for supporting one or more individual growing containers for containing growth medium and plants, and the plurality of valleys slope downward from a peak to a gutter proximate to the perimeter of the upper tray, the one or more of the plurality of valleys are in fluid communication with the gutter for channeling fluid collected into the gutter.

The system wherein the gutter is configured to be in fluid communication with a fluid drainage system.

Additional embodiments include the following, alone or in any combination.

Embodiment 1. A system for plant cultivation, comprising a ventilation system comprising an air box comprising an air passage extending from an inlet opening in a first end of the air box to an outlet opening in a second end of the air box, the air box comprising a centrifugal fan or tangential fan disposed in the air passage configured to move air from the first end to the second end of the air box.

Embodiment 2. The system of Embodiment 1 comprising a centrifugal fan having a vertical axis of rotation.

Embodiment 3. The system of Embodiment 2 wherein the centrifugal fan comprises a plurality of curved impeller vanes.

Embodiment 4. The system of Embodiment 2 comprising two or more centrifugal fans, each centrifugal fan having a vertical axis of rotation.

Embodiment 5. The system of Embodiment 2 wherein the inlet opening has a greater area than the outlet opening.

Embodiment 6. The system of Embodiment 2 wherein the inlet opening is generally rectangular, with a horizontal dimension greater than a vertical dimension.

Embodiment 7. The system of Embodiment 2 wherein the outlet opening has a horizontal dimension greater than a vertical dimension.

Embodiment 8. The system of Embodiment 2 wherein the first end of the air box has a vertical dimension greater than a vertical dimension of the second end of the air box.

Embodiment 9. The system of Embodiment 1 wherein ambient air enters the inlet opening in a generally horizontal direction and air exits the outlet opening in a generally horizontal direction.

Embodiment 10. The system of Embodiment 9 wherein each centrifugal fan comprises a plurality of curved impeller vanes.

Embodiment 11. The system of Embodiment 1 comprising a centrifugal fan having a horizontal axis of rotation.

Embodiment 12. The system of Embodiment 11 wherein the centrifugal fan comprises a volute housing wherein the outlet of the volute housing is in fluid communication with the outlet opening in the second end of the air box.

Embodiment 13. The system of Embodiment 11 wherein the inlet opening has a greater area than the outlet opening.

Embodiment 14. The system of Embodiment 11 wherein the inlet opening is generally rectangular, with a horizontal dimension greater than a vertical dimension.

Embodiment 15. The system of Embodiment 11 wherein the outlet opening has a horizontal dimension greater than a vertical dimension.

Embodiment 16. The system of Embodiment 11 wherein the first end of the air box has a vertical dimension greater than a vertical dimension of the second end of the air box.

Embodiment 17. The system of Embodiment 11 wherein ambient air enters the inlet opening in a generally horizontal direction and air exits the outlet opening in a generally horizontal direction.

Embodiment 18. The system of Embodiment 1 comprising a tangential fan having a horizontal axis of rotation, wherein the tangential fan directs air toward the outlet opening.

Embodiment 19. The system of Embodiment 18 wherein the inlet opening is generally rectangular, with a horizontal dimension greater than a vertical dimension.

Embodiment 20. The system of Embodiment 18 wherein the outlet opening has a horizontal dimension greater than a vertical dimension.

Embodiment 21. The system of Embodiment 18 wherein the first end of the air box has a vertical dimension greater than a vertical dimension of the second end of the air box.

Embodiment 22. The system of Embodiment 18 wherein ambient air enters the inlet opening in a generally horizontal direction and air exits the outlet opening in a generally horizontal direction.

Embodiment 23. The system of Embodiment 1 wherein the air box comprising a filter disposed in the air passage proximate to the first end.

Embodiment 24. The system of Embodiment 1, wherein the ventilation system further comprises a component to amend air before it exits the air passage.

Embodiment 25. The system of Embodiment 1, wherein the component to amend air comprises a heater, cooler, dehumidifier, humidifier, carbon dioxide (CO2) injector, ozone injector, ultraviolet light emitter, or combinations thereof.

Embodiment 26. The system of Embodiment 1, wherein the air box is configured to attach to a rack system for supporting cultivated plants.

Embodiment 27. The system of Embodiment 1 wherein the outlet opening is in fluid communication with an elongated duct assembly comprising one or more air passages, the duct assembly having a first end in fluid communication with the outlet opening, a second end opposed to the first end configured to be either closed or in fluid communication with a second duct assembly, and a plurality of orifices in the one or more air passages to distribute air out of the one or more air passages.

Embodiment 28. The system of Embodiment 27 wherein the plurality of orifices are configured to direct air from the duct assembly to above the duct assembly; or direct air from the duct assembly to below the duct assembly; or direct air from the duct assembly to above and below the duct assembly.

Embodiment 29. The system of Embodiment 27 wherein the one or more air passages in the duct assembly are each defined by an elongated bottom panel; a first elongated side member and a second elongated side member, each side member having a bottom end and a top end, wherein the bottom ends of the first and side members are engaged to opposed sides of the elongated bottom panel; and an elongated top panel with opposed first and second sides, the first side configured to engage the top end of the first side member and the second side configured to engage the top end of the second side member.

Embodiment 30. The system of Embodiment 29 wherein the bottom panel comprises a plurality of orifices to direct air from the duct assembly to below the duct assembly.

Embodiment 31. The system of Embodiment 29 wherein the top panel comprises a plurality of orifices to direct air from the duct assembly to above the duct assembly.

Embodiment 32. The system of Embodiment 29 wherein the bottom panel comprises a plurality of orifices to direct air from the duct assembly to below the duct assembly and the top panel comprises a plurality of orifices to direct air from the duct assembly to above the duct assembly.

Embodiment 33. The system of Embodiment 27 further comprising a tray comprising opposed sides and opposed ends defining a perimeter of the tray, and a raised region disposed within the perimeter of the tray.

Embodiment 34. The system of Embodiment 33, wherein the raised region of the tray comprises: a plurality of alternating parallel ridges disposed between the side walls and a plurality of valleys formed between adjacent ridges of the plurality of ridges, wherein one or more of the plurality of valleys are in fluid communication with a gutter; and optionally one or more of a plurality of holes in one or more of the plurality of ridges.

Embodiment 35. The system of Embodiment 34 wherein the plurality of holes are present and are in fluid communication with the plurality of orifices in the top panel of the duct assembly to direct air from the duct assembly to above the tray.

Embodiment 36. The system of Embodiment 35 wherein the bottom surface of the raised region of the tray comprises the top panel of the duct assembly.

Embodiment 37. The system of Embodiment 33, wherein the plurality of alternating parallel ridges comprise top surfaces defining a level plane for supporting one or more individual growing containers for containing growth medium and plants, and the plurality of valleys slope downward from a peak to a gutter proximate to the perimeter of the upper tray, the one or more of the plurality of valleys are in fluid communication with the gutter for channeling fluid collected into the gutter.

Embodiment 38. The system of Embodiment 37, wherein the gutter is configured to be in fluid communication with a fluid drainage system.

Embodiment 39. The system of Embodiment 27 wherein the duct assembly is engaged to an air box comprising an air passage extending from an inlet opening in a first end of the air box to an outlet opening in a second end of the air box, the air box comprising a centrifugal fan having a vertical axis of rotation disposed in the air passage configured to move air from the first end to the second end of the air box.

Embodiment 40. The system of Embodiment 27 wherein the duct assembly is engaged to an air box comprising an air passage extending from an inlet opening in a first end of the air box to an outlet opening in a second end of the air box, the air box comprising a centrifugal fan having a horizontal axis of rotation disposed in the air passage configured to move air from the first end to the second end of the air box.

Embodiment 41. The system of Embodiment 27 wherein the duct assembly is engaged to an air box comprising an air passage extending from an inlet opening in a first end of the air box to an outlet opening in a second end of the air box, the air box comprising a tangential fan having a horizontal axis of rotation disposed in the air passage configured to move air from the first end to the second end of the air box.

Embodiment 42. The system of Embodiment 27 wherein the duct assembly is engaged to an air box comprising a first air chamber extending from an inlet opening in a first end of the air box and a second air chamber extending from an outlet opening in a second end of the air box and a centrifugal fan or a tangential fan disposed between the first air chamber and the second air chamber, the fan in fluid connectivity with the first air chamber and the second air chamber to define an air passage configured to move air from the first end to the second end of the air box.

Embodiment 43. The system of Embodiment 42 wherein the second air chamber is configured to fit within an air passage within the duct assembly and the outlet directs air into an air passage within the duct assembly.

Embodiment 44. The system of Embodiment 43 wherein at least a portion of the centrifugal fan or at least a portion of the tangential fan is disposed within the second air chamber.

Embodiment 45. The system of Embodiment 44 wherein the centrifugal fan has a vertical axis of rotation and an entry in fluid communication with the first air chamber.

Embodiment 46. The system of Embodiment 45 wherein the centrifugal fan is disposed within the second air chamber.

Embodiment 47. The system of Embodiment 44 wherein the centrifugal fan has a horizontal axis of rotation and an entry in fluid communication with the first air chamber.

Embodiment 48. The system of Embodiment 47 wherein the centrifugal fan has a housing wherein the entry is disposed within the first air chamber and an exit is disposed in the second air chamber.

Embodiment 49. The system of Embodiment 44 wherein the tangential fan has a horizontal axis of rotation and an entry in fluid communication with the first air chamber.

Embodiment 50. The system of Embodiment 49 wherein the tangential fan has a housing wherein the entry is disposed within the first air chamber and an exit is disposed in the second air chamber.

Embodiment 51. A system for plant cultivation, comprising a ventilation system comprising an air box comprising a first air chamber extending from an inlet opening in a first end of the air box and a second air chamber extending from an outlet opening in a second end of the air box and a centrifugal fan or a tangential fan disposed between the first air chamber and the second air chamber, the fan in fluid connectivity with the first air chamber and the second air chamber to define an air passage configured to move air from the first end to the second end of the air box.

Embodiment 52. The system of Embodiment 51 wherein the air box is configured to engage a duct assembly to draw ambient air into the air box through the inlet opening and direct compressed air through the outlet opening into the duct assembly.

Embodiment 53. The system of Embodiment 52 wherein the outlet opening is in fluid communication with an elongated duct assembly comprising one or more air passages, the duct assembly having a first end in fluid communication with the outlet opening, a second end opposed to the first end configured to be either closed or in fluid communication with a second duct assembly, and a plurality of orifices in the one or more air passages to distribute air out of the one or more air passages.

Embodiment 54. The system of Embodiment 52 wherein the second air chamber is configured to fit within an air passage within the duct assembly and the outlet directs air into an air passage within the duct assembly.

Embodiment 55. The system of Embodiment 54 wherein at least a portion of the centrifugal fan or at least a portion of the tangential fan is disposed within the second air chamber.

Embodiment 56. The system of Embodiment 55 wherein the centrifugal fan has a vertical axis of rotation and an entry in fluid communication with the first air chamber.

Embodiment 57. The system of Embodiment 56 wherein the centrifugal fan is disposed within the second air chamber.

Embodiment 58. The system of Embodiment 54 wherein the centrifugal fan has a horizontal axis of rotation and an entry in fluid communication with the first air chamber.

Embodiment 59. The system of Embodiment 58 wherein the centrifugal fan has a housing wherein the entry is disposed within the first air chamber and an exit is disposed in the second air chamber.

Embodiment 60. The system of Embodiment 44 wherein the tangential fan has a horizontal axis of rotation and an entry in fluid communication with the first air chamber.

Embodiment 61. The system of Embodiment 60 wherein the tangential fan has a housing wherein the entry is disposed within the first air chamber and an exit is disposed in the second air chamber.

Embodiment 62. The system of Embodiment 52 wherein the plurality of orifices are configured to direct air from the duct assembly to above the duct assembly; or direct air from the duct assembly to below the duct assembly; or direct air from the duct assembly to above and below the duct assembly.

Embodiment 63. The system of Embodiment 52 further comprising a tray comprising opposed sides and opposed ends defining a perimeter of the tray, and a raised region disposed within the perimeter of the tray.

Embodiment 64. The system of Embodiment 63, wherein the raised region of the tray comprises: a plurality of alternating parallel ridges disposed between the side walls and a plurality of valleys formed between adjacent ridges of the plurality of ridges, wherein one or more of the plurality of valleys are in fluid communication with a gutter; and optionally one or more of a plurality of holes in one or more of the plurality of ridges.

Embodiment 65. The system of Embodiment 64 wherein the plurality of holes are present and are in fluid communication with the plurality of orifices in the top panel of the duct assembly to direct air from the duct assembly to above the tray.

Embodiment 66. The system of Embodiment 65 wherein the bottom surface of the raised region of the tray comprises the top panel of the duct assembly.

Many alternatives, modifications, and variations are enabled by the present disclosure. While specific embodiments have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the exemplary embodiments may be embodied otherwise without departing from such principles. Accordingly, Applicants intend to embrace all such alternatives, modifications, equivalents, and variations that are within the spirit and scope of the exemplary embodiments.