Photovoltaic panel device and system for optimizing the angular position of photovoltaic panels in a greenhouse - Patents.com

Abstract

An apparatus of photovoltaic panels is configured to be installed in a greenhouse having support beams. The apparatus has a frame. Each frame has at least one photovoltaic panel attached to a rod. At least one motor is mechanically connected to rotate one or more rods to direct each photovoltaic panel to a different fixed angle position. A fixture is disposed on the periphery of the apparatus. Each fixture has a size and shape to be attached to at least one of the support beams such that the apparatus is only supportable by the support beams. A system has at least one of the above apparatus, a controller, and a plurality of sensors. The controller is programmed to select an optimal fixed angle position for each photovoltaic panel to promote plant growth based on environmental and plant conditions and sensor output, and to command each motor to rotate each rod to the selected angle position.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Patent Application No. 17 / 197,131, filed March 10, 2021, and Israeli Patent Application No. 281407, filed March 10, 2021, the contents of which are incorporated by reference herein in their entireties.

[0002] The present invention relates in some embodiments to an arrangement of photovoltaic panels in a greenhouse, and more particularly, but not exclusively, to a control system configured to rotate the photovoltaic panels based on sensor output and environmental conditions to optimize plant growth. [Background technology]

[0003] The lack of sufficient space to generate electricity from solar energy has led to research into agrivoltaic solutions that offer dual use of land, growing crops and generating renewable electricity on the same area of ​​land. Summary of the Invention [Problem to be solved by the invention]

[0004] Previous agricultural photovoltaic solutions have focused on photovoltaic installations fixed to the roof of a greenhouse. Although these fixed installations have their advantages, they also have various challenges. First, they do not capture enough light in low irradiance conditions, which either require their removal or result in a significant reduction in agricultural yields. These installations are similar to other conventional greenhouse shading devices, such as shade nets, that typically must be removed in the winter to allow higher light levels to reach the crops. Second, conventional systems for installing photovoltaic panels on greenhouses require the installation of the panels on the roof of the greenhouse. Roof installation is typically done, at least in part, because the system incorporates heavy panels that rely on the roof structure to support them. However, roof-mounted panels are difficult to install and remove, especially if the panels need to be removed frequently due to seasonal changes in irradiance. Additionally, greenhouse roof-mounted panels may require very robust and therefore heavy mounting systems to operate efficiently in high wind conditions. In many countries, roof-mounted photovoltaic panels are required to withstand winds of up to 100km / h. Furthermore, panels made of certain materials installed on greenhouse roofs can show rapid deterioration due to harsh weather conditions and dust accumulation.

[0005] The present disclosure discloses a photovoltaic installation for use in a greenhouse. A lightweight photovoltaic panel is rotatably mounted within the greenhouse. The panel is light enough to be supported by an existing support structure for the greenhouse. Thus, the panel is easy to install and to incorporate into an existing greenhouse structure. A controller receives sensor input from a sensor that measures environmental conditions for promoting plant growth. The controller selects a rotation angle of the panel such that the panel is positioned at an optimal angle for promoting plant growth and for secondary solar energy generation. Thus, the panel does not need to be removed because the orientation of the panel is adjusted to best benefit plant growth. The greenhouse may further include a ventilation system. The controller operates the ventilation system in conjunction with the photovoltaic panel to balance light entering the greenhouse with the temperature requirements of the plants within the greenhouse.

[0006] According to a first aspect, an apparatus having a plurality of photovoltaic panels is disclosed, the apparatus being configured to be installed in a greenhouse having a roof supported by a plurality of support beams. The apparatus has a plurality of frames, each frame including at least one photovoltaic panel attached to a rod. The apparatus further includes at least one motor. Each motor is mechanically connected to rotate one or more corresponding rods to direct each photovoltaic panel to a plurality of different fixed angle positions. A plurality of fixtures are disposed on the periphery of the apparatus. Each fixture is sized and shaped to be attached to at least one of the plurality of support beams such that the apparatus is only supportable by the plurality of support beams.

[0007] Advantageously, each photovoltaic panel is rotatable by the action of a motor on the rod, which allows the positioning of the panel to be adjusted according to the required irradiance level of the crops in the greenhouse, without the need to remove the panel. Also, the panels are installed inside the greenhouse, thus protecting them from damage. Moreover, the panels are installed in the existing frame of the greenhouse, without requiring any additional structural support for the panels other than the support beams of the greenhouse itself.

[0008] In another implementation according to the first aspect, the support beams have arches and the frames are arranged as cross ties between the different arches, thereby enhancing the structural support of the frame members. Advantageously, the apparatus can not only rely on the existing support structure of the greenhouse for its own support, but also increase the structural stability of the greenhouse.

[0009] In another implementation according to the first aspect, each of the frame and rods is made from aluminum, which is a lightweight material suitable for the functions described herein for the frame and rods.

[0010] In other implementations according to the first aspect, each corresponding motor can maintain one or more corresponding rods at up to 50 different fixed angular positions. The multiple angular positions can ensure that the panels are positioned at optimal angles for plant growth and energy production.

[0011] In another implementation according to the first aspect, a system for optimizing the positioning of the angular positions of photovoltaic panels in a greenhouse is disclosed. The system includes at least one device of the photovoltaic panels according to the first aspect. A controller includes a wireless transceiver. The at least one wireless transceiver is associated with each frame and configured to receive instructions from the controller. The system further includes a plurality of sensors. Each of the plurality of sensors is configured to monitor at least one of air temperature, leaf temperature, root temperature, irradiance, humidity, and carbon dioxide concentration at each location in the greenhouse and generate a sensor output. The plurality of wireless transceivers are configured to transmit the sensor output to the controller. The controller is programmed to select an optimal fixed angle position of each photovoltaic panel to promote plant growth based on a combination of environmental conditions and plant conditions and the sensor output, and to command each corresponding motor to rotate one or more corresponding rods to the selected fixed angle position. Advantageously, the system positions each panel in an optimal position for promoting plant growth and generating energy by responding to the sensor output and environmental conditions.

[0012] Optionally, the plurality of sensors includes a plurality of sensor units mounted at different heights on vertical supports within the structure and configured to monitor air temperature, leaf temperature, irradiance, humidity, and carbon dioxide concentration, and a plurality of root temperature sensors disposed at the roots of plants within the greenhouse and configured to monitor root temperature. Placing the sensors at different vertical heights allows for a more accurate assessment of the irradiance and temperature requirements of the crops.

[0013] Optionally, a fan-based ventilation system is installed. The control unit is configured to command the ventilation system to circulate air in the greenhouse if the temperature sensed by the sensor unit above the plant height is higher than the temperature sensed by the sensor unit at the plant height and if the temperature at the plant height is lower than a predefined optimal temperature for plant growth. Thus, advantageously, the sensors at various vertical heights also provide information for the control of the ventilation system.

[0014] Optionally, the environmental conditions and plant conditions include the opacity of the photovoltaic panels, the range of light frequencies transmitted through the photovoltaic panels, the current date, the current time, the type of crop being grown, the date of planting of the crop, the geographic location of the greenhouse, the shape of the greenhouse, the material of the greenhouse cover, and the transmittance of the greenhouse cover. Based on these inputs, the controller can determine the minimum Daily Light Integral (DLI) required for each crop being grown, the amount of irradiance generated by the weather by day, and the corresponding angle of each of the panels required to allow the required amount of light to reach the crop.

[0015] Optionally, the sensor outputs include irradiance in various parts of the greenhouse, temperature in various parts of the greenhouse, humidity in various parts of the greenhouse, leaf temperature in various parts of the greenhouse, root temperature in various parts of the greenhouse, and carbon dioxide concentration in various parts of the greenhouse. Each of these outputs is taken into account by the controller when determining the optimal positioning of the panels.

[0016] Optionally, regardless of the state of the sensor output, the controller is configured to select a fixed angular position for each of the panels such that each plant in the greenhouse receives a predetermined minimum daily light integral (DLI), thus the controller prioritizes optimal positioning of the panels for plant growth and only secondarily for positioning of the panels for power generation.

[0017] Optionally, if the controller determines that the plant did not receive the predetermined minimum DLI on a particular day, the controller is configured to cumulatively achieve an average minimum DLI for the series of days by directing a fixed angular position of the panel for at least one subsequent day to exceed the predetermined minimum DLI for that subsequent day. Thus, advantageously, the controller is configured to ensure that the crop receives the required amount of light over the long term.

[0018] Optionally, the system further includes a fan ventilation system. The controller is configured to command the ventilation system to extract hot air from the top of the greenhouse when the temperature inside the greenhouse exceeds a predetermined temperature and to inject air from outside the greenhouse into the interior of the greenhouse when the carbon dioxide level inside the greenhouse falls below a predetermined level. The predetermined temperature and the predetermined level are determined based on environmental conditions and plant conditions. Advantageously, the controller uses the same environmental conditions and plant conditions to determine the angular positions of the panels and the operation of the fan ventilation system.

[0019] Optionally, the environmental conditions and plant conditions include appropriate ranges of maximum and minimum temperature and irradiance for each particular growth stage of the crop, and the controller is configured to maintain the temperature and irradiance levels within the appropriate ranges by adjusting the irradiance level for each crop via the rotation of the panels, and adjusting the temperature level for each crop via the rotation of the panels and operation of the ventilation system. For example, if the environmental conditions and plant conditions indicate that the crops require more illumination, the controller causes the rods to rotate the panels to allow more light to pass through the panels. If this increases the temperature above the optimum temperature for the crops, the ventilation system cools the greenhouse to the required temperature.

[0020] According to a second aspect, a method of optimizing the positioning of angular positions of photovoltaic panels in a structure to promote plant growth is disclosed. The structure has a plurality of frames, each frame having at least one photovoltaic panel on a rod. The structure further has at least one motor. Each motor is configured to rotate one or more corresponding rods and to maintain one or more corresponding rods at a plurality of fixed angle positions. The structure further has a wireless receiver. The method includes monitoring at least one of air temperature, leaf temperature, root temperature, irradiance, humidity, and carbon dioxide concentration at a location in the structure with a plurality of sensors in the structure, thereby generating a sensor output. The method further includes transmitting the sensor output to a controller, selecting an optimal fixed angle position of each photovoltaic panel to promote plant growth based on a combination of environmental conditions and plant conditions and the sensor output, and commanding at least one corresponding motor to rotate one or more corresponding rods to the selected fixed angle position. Advantageously, by practicing this method, each panel is angled in an optimal position for promoting plant growth and for generating energy.

[0021] In another implementation according to the second aspect, the environmental conditions and plant conditions include the opacity of the photovoltaic panels, the range of light frequencies passed by the photovoltaic panels, the current date, the current time, the type of crop being grown, the date of planting of the crop, the geographic location of the structure, the shape of the structure, the material of the cover of the structure, and the transmittance of the cover of the structure. Based on these inputs, the controller can determine the minimum daily light accumulation required for each crop being grown, the amount of irradiance generated by the weather by day, and the corresponding angle of each of the panels required to allow the required amount of light to reach the crop.

[0022] In other implementations according to the second aspect, the sensor outputs include irradiance at various parts of the structure, temperature at various parts of the structure, humidity at various parts of the structure, leaf temperature at various parts of the structure, root temperature at various parts of the structure, and carbon dioxide concentration at various parts of the structure, each of which is taken into account by the controller when determining optimal positioning of the panels.

[0023] In another implementation according to the second aspect, the method further includes selecting a fixed angular position for each of the panels such that each plant in the structure receives a predetermined daily light integral (DLI) regardless of the state of the sensor output. Thus, the method prioritizes optimal positioning of the panels for plant growth and only secondarily for positioning of the panels for power generation.

[0024] Optionally, the method further includes, if the controller determines that the plant did not receive the predetermined minimum DLI on a particular day, the controller directs a fixed angle position of the panel for at least one subsequent day to exceed the predetermined minimum DLI for that subsequent day, thereby cumulatively achieving an average minimum DLI for the series of days, advantageously such that in the long term the crop receives the required amount of light.

[0025] In another implementation according to the second aspect, the structure is a greenhouse and further comprises a fan ventilation system. The method further comprises instructing the ventilation system to extract hot air from an upper portion of the greenhouse when the temperature inside the greenhouse exceeds a predetermined temperature and to inject air from outside the greenhouse into the greenhouse when the carbon dioxide level inside the greenhouse falls below a predetermined level. The predetermined temperature and the predetermined level are determined based on the environmental conditions and the plant conditions. Advantageously, the control unit uses the same environmental conditions and the plant conditions to determine the angular position of the panels and the operation of the fan ventilation system.

[0026] Optionally, the environmental conditions and plant conditions include maximum and minimum appropriate ranges of temperature and irradiance for each particular growth stage of the crop. The controller is configured to maintain the temperature and irradiance levels within the appropriate ranges by adjusting the irradiance level for each crop through rotation of the panels and operation of the ventilation system. For example, if the environmental conditions and plant conditions indicate that the crop requires more illumination, based on the growth stage of the crop, the controller causes the rods to rotate the panels to allow more light to pass through the panels. If this increases the temperature above the crop's optimal temperature, the ventilation system cools the greenhouse to the required temperature.

[0027] Optionally, the method further includes adjusting the fixed angle position of each panel to track the movement of the sun as a secondary consideration to optimizing the fixed angle position of each panel for promoting plant growth. By tracking the movement of the sun, the energy output of the panels is maximized. The method prioritizes optimal positioning of the panels for plant growth and only secondarily positions the panels for power generation.

[0028] Optionally, the structure is an open frame placed on the open-field crop, and the plurality of sensors includes one or more anemometers, and the method further includes the steps of detecting wind speed and direction using the one or more anemometers, determining that the detected wind speed and direction exceed a maximum allowable wind speed according to the environmental state and the current fixed angle position of the at least one panel, and instructing the rotation of the at least one panel to a different fixed angle position. When the structure is an open frame, the panel is exposed to wind, and if the panel is exposed to a wind force higher than a predetermined level, the wind may damage the panel. Moving the panel and minimizing the wind load on the panel when the wind speed is above a predetermined level helps ensure that the panel remains safe under adverse weather conditions.

[0029] Other systems, methods, features, and advantages of the present disclosure will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all additional systems, methods, features, and advantages be included within the following description, be within the scope of the present disclosure, and be protected by the accompanying claims.

[0030] Certain embodiments of the present disclosure are described herein, by way of example only, with reference to the accompanying drawings. It is emphasized that the details shown below, with particular reference to the drawings, are for the purposes of illustration and for the purpose of detailed description of embodiments of the present invention. Similarly, from viewing the description together with the drawings, it will become apparent to those skilled in the art how embodiments of the present disclosure may be practiced. [Brief description of the drawings]

[0031] [Figure 1] 1 is a top view of an arrangement of photovoltaic panels according to an embodiment of the present disclosure; [Diagram 2] 2 is a top perspective view of the device of FIG. 1 according to an embodiment of the present disclosure; [Diagram 3] FIG. 2 is a front view of the device of FIG. 1 according to an embodiment of the present disclosure. [Figure 4] 2 is a side view of the device of FIG. 1 according to an embodiment of the present disclosure. [Diagram 5] FIG. 2 is a schematic diagram of the apparatus of FIG. 1 mounted within a greenhouse frame, according to an embodiment of the present disclosure. [Figure 6] FIG. 1 is a schematic diagram of a vertical column with multiple sensor units at different heights, according to an embodiment of the present disclosure. [Figure 7] FIG. 2 is a block diagram illustrating various components of a system for controlling the arrangement of the photovoltaic panel of FIG. 1 according to an embodiment of the present disclosure. [Figure 8] FIG. 2 is a schematic diagram illustrating the change in angle of the photovoltaic panel in the device of FIG. 1 under different irradiance conditions, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The present invention relates in some embodiments to an arrangement of photovoltaic panels in a greenhouse, and more particularly, but not exclusively, to a control system configured to rotate the photovoltaic panels based on sensor output and environmental conditions to optimize plant growth.

[0033] Before describing at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of elements and / or methods set forth in the following description and / or illustrated in the drawings and / or examples. The invention is capable of other embodiments and of being practiced or carried out in various ways.

[0034] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this disclosure belongs.Methods and materials similar or equivalent to those described herein can be used to practice or test the embodiments of this disclosure, but exemplary methods and / or materials are described below.In case of conflict, the patent specification, including definitions, shall prevail.In addition, materials, methods, and examples are merely illustrative and are not necessarily intended to be limiting.

[0035] 1-4, a photovoltaic panel apparatus 10 is configured to be installed in a structure for promoting plant growth, such as a greenhouse. Apparatus 10 is sometimes referred to herein as a module. FIG. 1 shows a top view of apparatus 10, FIG. 2 shows an upper perspective view of apparatus 10, FIG. 3 shows a front view of apparatus 10, and FIG. 4 shows a side view of apparatus 10.

[0036] The term "structure for promoting plant growth" as used in this disclosure encompasses greenhouses and open frame structures placed in fields. The term "greenhouse" as used in this disclosure refers to a structure having walls and a roof made primarily of transparent materials, such as glass, polyethylene, or other types of plastic, in which plants that require regulated climatic conditions are grown. The greenhouse has a frame made of support beams and a cover of transparent material and / or wall and roof panels supported by the support beams. The apparatus 10 may be installed in a greenhouse having any shape and made of any material. For example, the shape of the greenhouse may have one of a flat arch, a dome, a tunnel, a quonset, a gothic arch, a gable, a skillion, a lean-to, an even span, an uneven span, a ridge and furrow, an A-frame, or a sawtooth. Alternatively, the apparatus 10 is placed over an open field crop. In such an embodiment, a frame is constructed over the open field crop to support the apparatus 10. The frame is an open frame constructed in the open, meaning that there are no glass or plastic panels supported by the open frame, in some such embodiments, the frame is constructed solely to support the apparatus 10.

[0037] Also, the term "support beams" as used in this disclosure includes all materials used to support a frame for a greenhouse or other structure to facilitate plant growth, including, but not limited to, arches, purlins, rafters, braces, vertical beams, wood framing members, pipe framing members, and steel or iron trusses.

[0038] The apparatus 10 includes one or more frames 12. In the exemplary embodiment, each frame 12 is rectangular and has dimensions of approximately 1.5 x 2 m. Each frame 12 has at least one photovoltaic panel 14 attached to rods 16. Frame members 18 are disposed around the periphery of each frame 12 to surround the photovoltaic panel 14. Each frame 12 also includes at least one fixture 20 attached to the one or more frame members 18. The fixture 20 is sized and shaped to be attached to a support beam of a greenhouse or other structure for encouraging plant growth. The fixture 20 may also be adjustable to various lengths to allow for slight variations in dimensions between the frame members 18 and the support beam. In the exemplary embodiment, the fixture 20 includes a telescopic rod 23. A connector 24 may be attached to the telescopic rod 23 and disposed on the support beam and fitted around the support beam. In the illustrated embodiment, the connector 24 is in the shape of the letter Ω, but may assume any other suitable shape. Optionally, the connector 24 is also adjustable in size. Also, in addition to or in place of the Ω shaped connector 24 located on the fixture 20, other mounting means may be attached to the support beams of the greenhouse and the fixture 20 may be fitted into the Ω shaped connector or otherwise attached to the other mounting means.

[0039] Each panel 14 is connected to a wiring system within the hollow portion of the frame member 18. Depending on the size and electrical requirements of the devices 10, the frame 12 is connected in series or parallel to a microinverter (not shown) attached to each device 10. The microinverters provide power to the greenhouse energy grid for use within the greenhouse. Optionally, the energy grid includes a battery system and is the only power source for the greenhouse's electrical devices, such as the sensors and ventilation system described further herein. Optionally, the microinverters are connected to an external power grid to provide power outside the greenhouse.

[0040] In a preferred embodiment, the device 10 is designed to be installed in an existing greenhouse. For example, in FIG. 5, the device 10 is shown installed in a tunnel-shaped greenhouse 30. For such installation, the device 10 is designed as a modular plug-and-play system in which the number of frames 12 and the number of panels 14 per frame 12 can be changed depending on the dimensions of the existing greenhouse. In the illustrated embodiment, the device 10 has six frames 12, each frame 12 having three photovoltaic panels 14. This number of frames 12 and the number of panels 14 per frame 12 is merely exemplary, and any number of frames 12 and panels 14 may be used. The number of frames 12 may be limited based on practical considerations. One such consideration may be the architectural limitations of the greenhouse's support beams, i.e., the capacity of the support beams to support the weight of the frames 12. Another such consideration may be the maximum shade tolerance of the greenhouse, i.e., too many frames will create an impractically large amount of shading regardless of the angle of the panels 14.

[0041] Also, in preferred embodiments where the apparatus 10 is installed within an existing greenhouse, the apparatus 10 can be supported only by the support beams of the greenhouse, i.e., no additional structural support needs to be introduced into the greenhouse solely for the purpose of supporting the apparatus 10. For example, in FIG. 5, the apparatus 10 is attached to and supported by arch 32 of the greenhouse 30. If the greenhouse frame members include horizontal arch supports in addition to or instead of being supported by the arch, then the fixture 20 may be attached to those horizontal arch supports.

[0042] In an exemplary embodiment, as shown in Figure 5, the frames 12 are positioned as cross ties between different arches 32. Advantageously, in this configuration, the frames 12 provide additional structural support for the framing members.

[0043] The materials of the apparatus 10 are preferably lightweight so that the apparatus 10 can be supported entirely by the support beams of the greenhouse 30. For example, the rods 16 and frame members 18 may be made from aluminum.

[0044] Similarly, the panels 14 are preferably made of a lightweight photovoltaic material. Nearly 90% of solar panels used on roofs are currently made from polycrystalline silicon. Polycrystalline silicon panels weigh 20-30 kilograms per square meter and therefore often require additional support members to distribute their weight. Monocrystalline silicon panels have a comparable weight. While polycrystalline or monocrystalline silicon can be used for the panels 14 of the present disclosure, their weight makes it difficult to install the silicon panels within the existing frame of a greenhouse without additional support.

[0045] More recently, alternative photovoltaic materials have been developed that are significantly lighter and therefore better adapted for installation within existing greenhouses. For example, organic photovoltaic materials (OPVs) are photovoltaic materials that contain carbon-containing molecules. Organic photovoltaic materials are also known as plastic solar cells. OPVs weigh about 500 grams per square meter, making them more than 40 times lighter than their crystalline silicon equivalents. In addition, OPVs can be only a few millimeters thick, much thinner than crystalline silicon solar cells. Another advantage of OPVs is that they are semi-transparent, thus allowing some light to pass through them even when placed completely perpendicular to the sun's rays. In addition to OPVs, other lightweight photovoltaic materials that can be used for panel 14 include, but are not limited to, perovskite solar cells, dye-sensitized solar cells, and amorphous thin-film silicon solar cells.

[0046] There are many advantages to installing the apparatus 10 inside a greenhouse as opposed to placing the apparatus 10 on the roof of the greenhouse. First, panels mounted on the greenhouse roof will exhibit more rapid deterioration as compared to panels that are inside the greenhouse. Causes of deterioration of externally mounted panels include dust and harsh weather conditions. Thus, panels inside the greenhouse will enjoy increased life span and improved performance.

[0047] Referring again to FIG. 2, the panels 14 are rotatable relative to the frame 12. Specifically, each panel 14 is separately rotatable by rotation of the corresponding rod 16 mounted thereon. Each rod 16 may be fitted into the frame 12 using a bearing mount and may be rotatable within the mount. In an exemplary embodiment, the rods 16 are connected to at least one motor 26, which may be an AC motor. Each rod 16 is controlled by a single motor 26, which in turn controls one or more rods 16. The motors 26 are configured to adjust levers on the sides of the frame 12 connected to the rods 16. The levers rotate the rods 16 to a desired angle. The motors 26 may operate the levers via any mechanical connection known to those skilled in the art, such as gears, cams, linear actuators, and rotary actuators. The levers may maintain the rods 16 in a number of different angular positions relative to the plane of the frame 12. In an exemplary embodiment, the rods 16 may be maintained in up to 50 different angular positions. Each motor 26 is connected to a transceiver 22 , the location of which is shown diagrammatically, to receive instructions as to how to orient the panel 14 .

[0048] The number of rods 16 controlled by each motor can vary. In some embodiments, a single motor controls all of the rods 16 in a given frame 12. Optionally, in such embodiments, all of the panels 14 in a frame 12 are always moved in unison and oriented at the same angle. In other embodiments, a single motor controls the rods 16 of multiple frames 12. In such embodiments, a separate gear system connects the motor to each frame 12 so that the panels 14 of some frames 12 can be oriented differently than the panels 14 of other frames 12.

[0049] 6 and 7, a number of sensor units 40 are mounted on vertical posts 36 in a greenhouse or other structure for encouraging plant growth. The sensor units 40 are positioned at different heights on the vertical posts 36 to sense environmental conditions at different heights within the greenhouse microclimate. Optionally, the posts 36 are rotatable so that each sensor in a given sensor unit 40 can collect data from different points around the posts 36. FIG. 6 shows a schematic embodiment of a sensor unit 40 having a base 42, an air temperature sensor 44, a carbon dioxide concentration sensor 46, and a humidity sensor 48. As shown in FIG. 7, the sensor unit 40 may also have an irradiance sensor 50. In addition to one or more irradiance sensors 50 located at plant height, at least one irradiance sensor 50 is located above the height of the frame 12. The irradiance sensor 50 above the height of the panel 50 measures changes in irradiance due to various weather conditions, while the irradiance sensor 50 at plant height measures the effective irradiance reaching each plant. The sensor unit 40 may further include a leaf temperature sensor 52. For example, a temperature probe may extend from the base 42 and be positioned above the leaf at the same height as the sensor unit 40. In addition to being included in the sensor unit 40, each of the above-mentioned sensors may alternatively be fixed separately within the greenhouse and transmit separate wireless sensor outputs to the transceiver 64 of the control unit 62.

[0050] Wiring 38 provides power to each sensor. In the illustrated embodiment, wiring 38 is within the hollow portion of post 36, but wiring 38 may be in any other convenient location. Optionally, wiring 38 also includes a data transfer cable for communicating sensor output to controller 62. In addition to or instead of a data transfer cable, each post 36, or each sensor unit 40, includes a transceiver for communicating sensor output to controller 62.

[0051] FIG. 7 is a block diagram illustrating various components of a system 60 for optimizing the angular positioning of a photovoltaic panel 14 in a greenhouse or other structure for promoting plant growth. The system 60 includes at least one device 10 having, among other things, one or more frames 12, one or more motors 26, and one or more transceivers 22. A control unit 62 has a transceiver 64. The transceiver 64 is configured to receive wireless transmissions from the sensor units 40 from corresponding transceivers. In addition to the above-mentioned sensors, the system 60 also has one or more root temperature sensors 54 configured in the roots of one or more crops growing in the structure for promoting plant growth. If the structure is an open-frame structure, the system 60 further has at least one anemometer 56 for measuring wind direction and speed. The types of sensors that may be included in the system 60 are not limited to the above-mentioned examples, and other types of sensors may be included as well.

[0052] The system 60 may further include a ventilation system 66, such as a fan-based ventilation system. The ventilation system 66 may be configured to, among other things, circulate air within the greenhouse, extract air from the greenhouse, and exchange air between the greenhouse and an external environment, as described further below. The controller 62 may communicate instructions to the ventilation system 66 via the transceiver 64.

[0053] The control unit 62 may be a programmable logic controller including a processing circuit. The processing circuit may include a computer readable storage medium (or media) having computer readable program instructions for causing a processor to perform aspects of the present invention. The computer readable storage medium may be a tangible device capable of holding and storing instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof.

[0054] The computer-readable program instructions described herein can be downloaded into a corresponding computing / processing device from a computer-readable storage medium or over a network (e.g., the Internet, a local area network, a wide area network, and / or a wireless network) to an external computer or external storage device.

[0055] The computer-readable program instructions may execute entirely on the processing circuit, partially on the processing circuit, as a stand-alone software package, partially on the processing circuit and partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the processing circuit via any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (e.g., via the Internet using an Internet Service Provider). In some embodiments, electronic circuits, including, for example, programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), may execute the computer-readable program instructions by utilizing state information of the computer-readable program instructions to personalize the electronic circuit to perform aspects of the present invention.

[0056] The control unit 62 includes a memory. The memory may be preloaded with a library of data regarding optimal growing conditions for various crops and / or crop varieties at various stages of growth. These growing conditions include minimum and maximum desired ranges of irradiance in the Photosynthetically Active Radiation (PAR) range, temperature, humidity, CO2 concentration, and other dynamic factors that change during the day and / or season. Also preloaded is a database of sun positions at various times of the day and years for various locations.

[0057] In operation of the system 60, one or more of the sensors (e.g., air temperature sensor 44, carbon dioxide concentration sensor 46, humidity sensor 48, irradiance sensor 50, leaf temperature sensor 52, root temperature sensor 54, anemometer 56, and / or any other installed sensors) generate sensor outputs and transmit the sensor outputs to the controller 62. The controller 62 selects an optimal fixed angle position for each photovoltaic panel 14 to promote plant growth. The selection is based on a combination of the sensor outputs and environmental conditions and plant conditions. The controller 62 then commands each motor 26 to rotate each corresponding rod 16 to the selected fixed angle position. As mentioned above, in an exemplary embodiment, the panels 14 may be moved to up to 50 preprogrammed angles per day.

[0058] The environmental conditions and plant conditions considered by the control unit 62 when determining the angular position of the panel 14 may include static and dynamic factors. Static factors may include the type of photovoltaic material used in the panel 14, the opacity of the photovoltaic panel 14 (e.g., if the photovoltaic panel is translucent as in the case of organic photovoltaic panels), and the range of frequencies of light passed by the photovoltaic panel 14. Static factors may further include the current date (e.g., whether it is a long-sunny summer day or a short-sunny winter day) and the current time of day, which affects the angle of the sun relative to the greenhouse. Another static factor is the type of crop being grown, and, if appropriate, the variety of the crop being grown. Different crops grow under different conditions of carbon dioxide concentration, irradiance, temperature, and humidity. Yet another relevant static factor is the date of planting of the crop, since optimal growing conditions change depending on the stage of the plant's development. A fifth relevant static factor is the geographic location of the structure. The geographic location of the structure determines the amount and timing of sunlight the structure receives on any given day. The geographic location may be defined to a high degree of precision (e.g., arc second resolution). Relatedly, the controller 62 may take into account other factors related to the structure itself, such as the shape of the structure (e.g., any of the greenhouse shapes listed above), the material of the structure's cover, if it has a cover (e.g., glass, polyethylene, or other plastic), and the transparency of the greenhouse cover.

[0059] Additionally, the control unit 62 takes into account various dynamic factors quantified by the sensor outputs, which may include irradiance in various parts of the structure, temperature in various parts of the structure, humidity in various parts of the structure, leaf temperature in various parts of the structure, root temperature in various parts of the structure, and carbon dioxide concentration in various parts of the structure.

[0060] FIG. 8 shows a schematic of the effect of controlling the angle of the panel 14 in the greenhouse 30. The maximum irradiance level is when the panel is at 90° solar incidence, i.e., parallel to the sun, allowing all sunlight to enter the greenhouse. The minimum irradiance level is when the panel is at 0° solar incidence and blocks sunlight. In the upper diagram, the panel 14 is oriented perpendicular to the sun's rays, as represented by the arrow. As a result, less sunlight reaches the plant 70. This orientation is suitable for situations where there is high irradiance that exceeds the irradiance required for plant growth. The panel 14 is tilted to provide maximum shading to the plant 70 and maximize the electrical output generated by the photovoltaic panel 14. In the lower diagram, the panel 14 is oriented parallel to the sun's rays, allowing the maximum amount of sunlight to pass through the device 10 to reach the plant 70. Conversely, the amount of electricity generated by the panel 14 is minimal. This orientation is suitable for low irradiance situations as all of the irradiance provided by the sun is directed towards the plant 70 to promote plant growth. Optionally, regardless of the state of the sensor output, the control unit 62 is configured to select fixed angular positions for the panels 14 such that each plant in the structure receives a predetermined minimum daily light integral (DLI). The term "daily light integral" as used in this disclosure refers to the number of photosynthetically active photons (individual particles of light in the 400-700 nm range) that accumulate in a square meter over a 24-hour period. DLI is typically expressed as the number of moles of photons per square meter per day.

number

number

number

[0061] Thus, in an exemplary embodiment, the controller 62 is programmed to control the positioning of the panels 14 so that each plant receives a predetermined minimum DLI during the day based on the type of crop and stage of growth. Once the controller 62 determines that the target DLI has been reached, based on input from, for example, the plant height irradiance sensor 50, the controller 62 commands the motors 26 to rotate the panels 14 to maximize power production. For example, the controller 62 may instruct the motors 26 to rotate the panels 14 so that they track the sun, i.e., so that they are always oriented perpendicular to the sun's rays as shown in the top half of FIG. 8.

[0062] It should be noted that maximizing power generation is a secondary consideration. The primary consideration in the operation of the control unit 62 is to promote plant growth. Although solar tracking systems for photovoltaic panels are known, such existing tracking systems are designed only to maximize electricity yield by orienting the photovoltaic panel toward the sun. Such devices change their orientation throughout the day to follow the path of the sun, thereby minimizing the angle of incidence between the incoming light and the panel (the angle that the light ray makes with a line perpendicular to the surface). This increases the amount of energy the installation generates. These devices typically achieve this result by mounting a movable panel on an electric motor that moves according to input from an irradiance sensor. The system may be single-axis, where the sun is tracked from east to west during the day, or dual-axis, where the sun is tracked on the vertical axis as well.

[0063] In system 60, the tracking system follows the sun on one axis, but its movement is adjusted by additional factors that, as discussed above, determine the agricultural yield, both in terms of quantity and quality, of the crops grown in greenhouse 30. Crop production, rather than electrical output, is the first priority for system 60.

[0064] If the control 62 determines that the plants did not receive the predetermined minimum DLI on a particular day or series of days (e.g., because the days were very cloudy), the control 62 may be configured to direct a fixed angle position of the panels on at least one subsequent day to exceed the predetermined minimum DLI on that subsequent day. For example, if the predetermined minimum DLI is 10 and on day 1 the control 62 determines that the plants received a DLI of 5, then on the following day the control 62 may direct the opening of the panels 14 to achieve a minimum DLI of 15, or any other suitable DLI, subject to known saturation limits. Cumulatively, the average minimum DLI for the series of days is achieved.

[0065] In addition to ensuring that each plant receives a minimum DLI, the control unit 62 can also be programmed to adjust the temperature by increasing the shade to reduce the temperature or decreasing the shade to allow more radiation to enter and be captured.

[0066] Each greenhouse crop has a recommended maximum and minimum range of temperature and irradiance for each specific growth stage. Similar to irradiance levels, temperature ranges can be on a scale of 1 to 10, with 1 indicating the minimum level of desired temperature and 10 indicating the maximum level of desired temperature. Some crops may be more tolerant or more vulnerable to either excess heat or excess irradiation during some growth stages. The control unit 62 is programmed to optimize irradiance and temperature to improve crop production.

[0067] As described above in relation to FIG. 7, the system 60 further includes a fan-based ventilation system 66. The controller 62 is configured to operate the ventilation system to control the temperature and carbon dioxide level within the greenhouse 30. For example, if the air temperature sensor 44 located at the plant height indicates that the temperature is lower than a predetermined optimum temperature for plant growth, but the air temperature sensor 44 located at the sensor unit 40 higher than the plant height indicates that the temperature is higher, the controller 62 instructs the ventilation system 66 to circulate air within the greenhouse 30, so that warmer air is circulated to the plant height. This scenario may typically occur during winter. As another example, the controller 62 is configured to instruct the ventilation system 66 to extract hot air from the top of the greenhouse 30 if the temperature within the greenhouse 30 exceeds a predetermined temperature. As yet another example, the controller 62 may instruct the ventilation system 66 to inject air from outside the greenhouse 30 into the greenhouse interior if the carbon dioxide level within the greenhouse 30 falls below a predetermined level. These predetermined temperatures and predetermined carbon dioxide levels may be determined based on the environmental conditions and plant conditions described above.

[0068] Additionally, the controller 62 may operate the ventilation system 66 in cooperation with the motors 26 to balance ideal temperature and irradiance conditions for plants growing within the greenhouse 30. For example, the controller 62 may be programmed to reach a target irradiance (DLI) and maintain air temperature between set maximum and minimum values. These target ranges may be set for each particular growth stage of the crop. The controller 62 is configured to adjust the irradiance level for each crop via the rotation of the panels 14 and adjust the temperature level for each crop via the rotation of the panels 14 and operation of the ventilation system to maintain temperature and irradiance levels within the appropriate ranges.

[0069] The following example illustrates the operation of the control unit 62 to accommodate desired irradiance and temperature in a system where irradiance and temperature are measured on a scale of 1 to 10. Crop A may be more vulnerable than crop B to high temperatures during early growth stages, but is less sensitive to irradiance levels at the higher levels of the recommended range. In later stages of growth, crop A is vulnerable to high levels of irradiance. In such a case, from day 1 to day 45 after planting, the control unit 62 is programmed to turn on the cooling fans of the ventilation system 66 when the temperature reaches level 5 of the recommended range, but to leave the photovoltaic panels 14 at maximum tracking power at 0° to the sun until it reaches level 8 of the recommended irradiance range. The panels 14 are then rotated 45° from the sun until it reaches level 10, at which time power generation is maximized when the panels are rotated 90° to the sun. After 45 days after planting, the system 60 is programmed to rotate the panels 90° to the sun and operate the cooling fans without reference to irradiance levels after the irradiance reaches level 4.

[0070] Crop B, on the other hand, may be equally sensitive to both high irradiance and high temperature at all stages of development, in which case the control unit 60 would be programmed to begin reducing irradiance and temperature when both inputs reach Level 2 of the recommended range.

[0071] Referring again to FIG. 7, as described above, the system 60 can be installed on an open frame structure over an open field crop. The advantage of installing the system 60 over an open field crop is that a larger number of panels 14 can be deployed. However, the drawback is that the panels 14 are exposed to adverse environmental conditions. In particular, the panels 14 are light weight and therefore susceptible to damage, especially from strong winds. Thus, in an embodiment of the system 60 installed on an open frame structure, the sensor includes one or more anemometers 56. A method of operation of the system 60 on an open frame structure includes detecting wind speed and direction using the anemometers 56. The wind exerts different torques on the panels 14 depending on the angular position of the panels 14, the wind direction, and the wind speed. The control unit 62 is preprogrammed with a maximum torque tolerance for the panels 14. If the control unit 62 determines that the detected wind speed and wind direction exceed the maximum tolerance for the wind speed of the panels 14 at the current orientation of the panels 14, the control unit 62 directs the rotation of the panels 14 to a different fixed angle position to minimize wind loads. The data regarding panel orientation and allowable wind speed limits are static data that are loaded into the control unit 62 as override instructions that take precedence over all other inputs when wind may jeopardize the system. In all other respects, the system 60 may operate identically in an open-air building and in a greenhouse.

[0072] It is expected that many related photovoltaic materials and many related types of sensors suitable for the functions described herein will be developed during the life of the patent resulting from this application, and the scope of the terms photovoltaic materials and sensors is intended to include a priori all such new technologies.

[0073] As used herein, "about" refers to ±10%.

[0074] The words "comprises," "comprising," "includes," "including," "having" and conjugations thereof mean "including but not limited to." This term encompasses the terms "consisting of" and "consisting essentially of."

[0075] The term "consisting essentially of" means that a composition or method may include additional components and / or steps, provided that the additional components and / or steps are Only if the basic and novel characteristics of the claimed composition or method are not materially altered.

[0076] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, "a compound" or "at least one compound" includes a plurality of compounds, and may also include mixtures thereof.

[0077] "Exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments, and / or does not exclude the incorporation of features from other embodiments.

[0078] "Optionally" is used herein to mean "provided in some embodiments and not provided in other embodiments." Any particular embodiment of the invention may include multiple "optional" features, unless those "optional" features contradict each other.

[0079] Throughout this application, various embodiments of the invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity, and is not an inflexible limitation of the scope of the invention. Thus, the description of a range should be considered to specifically disclose all of the possible subranges, as well as each individual numerical value within that range. For example, the description of a range such as 1 to 6 is intended to specifically disclose not only the subranges 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., but also each individual numerical value within that range, e.g., 1, 2, 3, 4, 5, and 6. This applies regardless of the magnitude of the range.

[0080] Whenever a numerical range is given herein, it is intended to include any recited number (fractional or integer) within the range given. The phrases "range between" a first designated number and a second designated number and "range from" a first designated number to a second designated number are used interchangeably herein and are intended to include the first designated number and the second designated number, and all fractional and integer numbers therebetween.

[0081] It will be understood that certain features of the invention that are, for clarity, described in the context of separate embodiments, may also be provided in a single embodiment in any combination of those features. Conversely, several features of the invention that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or with respect to other described embodiments as appropriate. Certain features described in the context of various embodiments should not be construed as essential to that embodiment, unless the particular embodiment is inoperable without that element.

[0082] While the present invention has been described in conjunction with specific embodiments thereof, many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claims.

[0083] It is the intention of the applicants that all publications, patents, and patent applications mentioned in this specification are incorporated herein by reference in their entirety to the same extent as if each individual publication, patent, and patent application was specifically and individually incorporated herein by reference. In addition, citation or identification of any reference in this application should not be construed as an admission that such reference is available as prior art to the present invention. Nor should it necessarily be construed as limiting, to the extent that section headings are used. In addition, the priority documents of this application, if any, are incorporated herein by reference in their entirety.

Claims

1. A system for optimizing angular positioning of photovoltaic panels within a greenhouse, comprising:

1. An apparatus configured to be installed in a greenhouse having a plurality of photovoltaic panels and a roof supported by a plurality of support beams, the apparatus comprising: a plurality of frames each comprising at least one rod and at least one photovoltaic panel attached to one of the at least one rod; at least one motor, each mechanically connected to rotate one or more corresponding rods to direct each photovoltaic panel into a plurality of different fixed angular positions; a plurality of fixtures disposed around the periphery of the apparatus, each of which is sized and shaped to be attached to at least one of the plurality of support beams such that the apparatus can be supported only by the plurality of support beams and the apparatus can be installed within the greenhouse under the roof; An apparatus comprising: A control unit; a plurality of sensors each configured to monitor at least one of air temperature, leaf temperature, root temperature, irradiance, humidity, and carbon dioxide concentration at a location within the greenhouse, generate a sensor output, and provide the sensor output to the controller; Equipped with the control unit is programmed to select a fixed angular position for each photovoltaic panel based on a combination of environmental and plant conditions and the sensor output to promote plant growth, and to command each corresponding motor to rotate one or more corresponding rods to the selected fixed angular position; The environmental conditions and plant conditions include the opacity of the photovoltaic panels, the range of light frequencies transmitted through the photovoltaic panels, the current date, the current time, the type of crop being grown, the date of planting of the crop, the geographic location of the greenhouse, the shape of the greenhouse, the material of the cover of the greenhouse, and the transmittance of the cover of the greenhouse. system.

2. The support beams include arches and the frames are arranged as cross ties between the different arches, thereby providing enhanced structural support for the frame members. The system of claim 1 .

3. Each of the frame and the rods is made of aluminum. The system of claim 1 .

4. each corresponding motor is capable of maintaining said one or more corresponding rods in up to 50 different fixed angular positions; The system of claim 1 .

5. The plurality of sensors include a plurality of sensor units mounted at various heights on vertical supports within the greenhouse and configured to monitor air temperature, leaf temperature, irradiance, humidity, and carbon dioxide concentration; a plurality of root temperature sensors disposed on the roots of plants in the greenhouse and configured to monitor root temperatures; The system of claim 1 .

6. and a ventilation system with fans, the control unit being configured to instruct the ventilation system to circulate air in the greenhouse when a temperature sensed by a sensor unit above a plant height is higher than a temperature sensed by a sensor unit at the plant height and when the temperature at the plant height is lower than a predefined optimal temperature for plant growth. The system of claim 1 .

7. the sensor output comprises at least one selected from the group consisting of irradiance in various parts of the greenhouse, temperature in various parts of the greenhouse, humidity in various parts of the greenhouse, leaf temperature in various parts of the greenhouse, root temperature in various parts of the greenhouse, and carbon dioxide concentration in various parts of the greenhouse; The system of claim 1 .

8. and wherein the controller is configured to select a fixed angular position for each of the photovoltaic panels such that each plant in the greenhouse receives a predetermined minimum Daily Light Integral (DLI), regardless of the state of the sensor output. The system of claim 1 .

9. If the controller determines that the plant does not receive a predetermined minimum DLI on a particular day, the controller is configured to cumulatively achieve an average minimum DLI for a series of days by directing the fixed angular position of the photovoltaic panel for at least one subsequent day to exceed the predetermined minimum DLI for the subsequent day. The system of claim 8.

10. and a fan ventilation system, wherein the controller is configured to command the ventilation system to extract hot air from an upper portion of the greenhouse when a temperature inside the greenhouse exceeds a predetermined temperature and to inject air from outside the greenhouse into the interior of the greenhouse when a carbon dioxide level inside the greenhouse falls below a predetermined level, the predetermined temperature and the predetermined level being determined based on a condition of the environment and a condition of the plants. The system of claim 1 .

11. the environmental conditions and plant conditions include appropriate maximum and minimum ranges of temperature and irradiance for a particular growth stage of a crop, and the control unit is configured to maintain the temperature and irradiance levels within the appropriate ranges by adjusting the irradiance level of each crop via the rotation of the photovoltaic panels and adjusting the temperature level of each crop via the rotation of the photovoltaic panels and operation of the ventilation system. The system of claim 10.

12. As a secondary consideration to optimizing the angular position of each panel to promote plant growth, the controller is configured to adjust the fixed angular position of each panel to track the movement of the sun. The system of claim 1 .

13. 1. A method for optimizing angular positioning of photovoltaic panels in a structure for promoting plant growth, comprising: The building comprises a plurality of frames, each frame comprising at least one rod, at least one photovoltaic panel, each frame mounted on one of the at least one rod, and at least one motor configured to rotate one or more corresponding rods and to maintain the one or more corresponding rods at a plurality of fixed angular positions; The structure is configured for dual use, comprising at least one of being installed inside an existing greenhouse under the roof of the greenhouse or placed over open field crops; The method comprises: generating a sensor output by monitoring at least one of air temperature, leaf temperature, root temperature, irradiance, humidity, and carbon dioxide concentration at a location within the structure using a plurality of sensors within the structure; providing the sensor output to a controller; selecting, with the controller, a fixed angular position for each photovoltaic panel to promote plant growth based on a combination of environmental conditions and plant conditions and the sensor output; commanding at least one corresponding motor to rotate the one or more corresponding rods to the selected fixed angular position; Including, The method, wherein the environmental conditions and plant conditions comprise at least one selected from the group consisting of opacity of the photovoltaic panels, the range of light frequencies passed by the photovoltaic panels, the current date, the current time, the type of crop being grown, the date of planting of the crop, the geographic location of the structure, the shape of the structure, the material of a cover of the structure, and the transmittance of the cover of the structure.

14. the sensor output comprises at least one selected from the group consisting of irradiance at various portions of the structure, temperature at various portions of the structure, humidity at various portions of the structure, leaf temperature at various portions of the structure, root temperature at various portions of the structure, and carbon dioxide concentration at various portions of the structure; The method of claim 13.

15. selecting a fixed angular position for each of the photovoltaic panels such that each plant within the structure receives a predetermined minimum daily light integral (DLI) regardless of the state of the sensor output. The method of claim 13.

16. and if the control unit determines that a plant has not received a predetermined minimum DLI for the plant on a particular day, then cumulatively achieving an average minimum DLI for a series of days by commanding the fixed angular position of the photovoltaic panel for at least one subsequent day to exceed the predetermined minimum DLI for the subsequent day. The method of claim 15.

17. The structure is a greenhouse and further comprises a ventilation system with a fan, the method further comprising the steps of instructing the ventilation system to extract hot air from an upper portion of the greenhouse when a temperature inside the greenhouse exceeds a predetermined temperature and to inject air from outside the greenhouse into an interior of the greenhouse when a carbon dioxide level inside the greenhouse falls below a predetermined level, the predetermined temperature and the predetermined level being determined based on the condition of the environment and the condition of the plants. The method of claim 13.

18. the environmental conditions and plant conditions include appropriate maximum and minimum ranges of temperature and irradiance for each particular growth stage of a crop, and the control unit is configured to maintain the temperature and irradiance levels within the appropriate ranges by adjusting the irradiance level for each crop via rotation of the photovoltaic panels and operation of the ventilation system; 20. The method of claim 17.

19. and adjusting the fixed angle position of each panel to track the movement of the sun as a secondary consideration to optimizing the fixed angle position of each panel to promote plant growth. The method of claim 13.

20. the structure is an open frame positioned over open-field crops, and the plurality of sensors further comprises one or more anemometers; detecting wind speed and direction using the one or more anemometers; determining that the detected wind speed and direction exceeds a maximum allowable wind speed depending on the environmental conditions and a current fixed angle position of at least one panel; and indicating rotation of the at least one panel to different fixed angular positions. The method of claim 13.

Images