Abstract:
A sun tracking plant growing system includes a body having a first face, a second face opposed to the first face and a peripheral connecting edge which is relatively small, as compared to the size of the first face and the second face. A mounting enables the body to pivot about a pivot axis. Plant supports, which receive plants, are supported by the body. A sun tracking mechanism is provided which senses or calculates the position of the sun and adjusts the orientation of the body about the pivot axis to maintain a selected portion of the peripheral connecting edge of the body facing the sun so as to provide desirable and naturally attenuated sunlight exposure according to plants&#39; needs on both faces throughout a day. This system allows that multiple rows or single row of the plural bodies are arrayed closely together without creating shadows to each other.

Description:
FIELD 
       [0001]    There is described a growing system for photosynthetic organisms, such as plants and algae, that tracks the movement of the sun in a fashion to allow desirable and controlled sunlight exposure. 
       BACKGROUND 
       [0002]    Although sun-tracking systems are commonly used with solar collectors to allow maximum solar collection by tracking the movement of the sun across the sky, growing systems for plants are generally fixed. As a result, plants are in direct sunlight for a portion a day often over-exposed with too much light particularly When sunlight energy is highest and in indirect sunlight or shade for the balance of the day leading to insufficient light. What is required is a sun tracking system that meets the needs of photosynthetic organisms such as plants and algae. 
       SUMMARY 
       [0003]    According to one aspect, there is provided a sun tracking growing system including a body having a first face, a second face opposed to the first face and a peripheral connecting edge which is relatively small, as compared to the size of the first face and the second face. A mounting enables the body to pivot about a pivot axis. Plant supports, which receive plants, are supported by the body along the first face, the second face or both. A sun tracking mechanism is provided which senses or calculates the position of the sun and adjusts the orientation of the body about the pivot axis to maintain a selected portion of the peripheral connecting edge of the body facing the sun. 
         [0004]    With the sun tracking growing system, as described above, plants supported along either the first face, the second face or both are directly exposed to sunlight throughout the day, without shading each other. Sun tracking systems used with solar collectors are designed to maximize sunlight exposure and as such, tend to overexpose plants throughout an extended period of a day when the light energy is highest, since photosynthesis is saturated at one twentieth to one quarter of full sunlight for most plants. In contrast, the sun tracking growing system described allows for the adjustment and natural attenuation of sunlight exposure according to what plants need. 
         [0005]    According to another aspect there is provided a method of having a growing system tracking the sun. A first step involves providing a body having a first face, a second face opposed to the first face and a peripheral connecting edge which is relatively small, as compared to the size of the first face and the second face. A second step involves mounting the body to pivot about a pivot axis. A third step involves placing plants into plant supports which are supported by the body along the first face, the second face, or both. A fourth step involves sensing or calculating the position of the sun. A fifth step involves adjusting the orientation of the body about the pivot axis to maintain a selected portion of the peripheral connecting edge of the body facing the sun. 
         [0006]    There can he a number of ways to enable the orientation adjustment of the growing body (or panel). For example, one way is to align the body towards South and North, and move along with the daily changes in sunray so that the two sides of panel are always in parallel to the sunray. Another possible example is to align the body towards East and West, and adjust along with the seasonal as well as daily changes in sun&#39;s altitude (or sunray) so as to maintain the two sides of panel always in parallel to the sunray. 
         [0007]    It will be appreciated that there are a number of ways the pivot axis can be arranged. For example, the pivot axis about which the body pivots could be a substantially horizontal pivot axis. Alternatively, the pivot axis about which the body pivots could be a substantially vertical pivot axis. Although horizontal and vertical are the most logical orientations for the pivot axis, it would also be possible to place the pivot axis in an orientation that is neither horizontal nor vertical. 
         [0008]    While there could be a single body, it is envisaged that there will be a plurality of bodies positioned in parallel spaced relation, each of the bodies tracking the sun concurrently. 
         [0009]    While there could be a single row of plural bodies, it is envisaged that there will be multiple rows of plural bodies positioned in parallel with all rows tracking the sun concurrently. 
         [0010]    The body can take a number of forms. It could be a solid growing wall, In the preferred embodiment the body is an open frame with plants are supported along the first face, the second face or both by plant supports. When growing algae, the plant supports are any containers like cylindrical tubes or fiat panels containing liquid nutrients. 
         [0011]    It is envisaged that the plants or cylindrical tubes will be positioned in spaced relation along one of a width or a length of the frame. In order for light to reach the plants or algae from all sides, it is preferred that the plants or cylindrical tubes are staggered, so that they are alternatively positioned toward first face and then toward the second face, which allows light to reach the back side of plant supports. 
         [0012]    Different species or varieties of plants require or can tolerate different amounts of sunlight. It is preferred that the body is wedge shaped and a thin edge of the wedge is the selected portion of the peripheral connecting edge of the body which is maintained facing the sun as the movement of the sun is tracked. The amount of sunlight exposure is determined by the angular relationship between the first face and the second face (i.e. the tapering of the panel in the middle). When the first face and the second thee are parallel, there is a minimal sunlight reaching the plants on both sides. As the angle between the first face and the second face increases, the sunlight exposure of the first face and the second face also increases. This enables the body to be tailored to suit the needs of a particular species of plants. It will be appreciated that When the angle of the first thee and the angle of the second face is equal, the first face and the second face receive equal sun exposure. It will also be appreciated that the angle of the first face and the angle of the second face may also be unequal, so that the first face and the second face receive unequal sun exposures so as to suit different needs of different plant species or varieties. 
         [0013]    The sun is not available at night or when there is heavy cloud cover. For that reason, even more beneficial results may be obtained when an artificial light source is supported by the body to provide artificial light to the plant supports when sunlight is not available or insufficient. The addition of artificial light creates a hybrid growing system capable switching between sunlight and artificial light, as required. 
         [0014]    As the growing systems are scaled up in size, the weight increases and movement becomes more difficult. Even more beneficial results may, therefore, be obtained when the sun tracking mechanism includes a hydraulic or mechanical spring and/or weight supports to assist in movement of the body. 
         [0015]    Although the growing body is, in general, fixed on a flat ground, potential beneficial results may be obtained by adjusting the slope or aspect of the body, relative to the wound, in order, for example, to synchronize with the seasonal changes in sun&#39;s altitude. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    These and other features will become more apparent from the following description in which reference is made to the appended drawings. The drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein: 
           [0017]      FIGS. 1 a  and 1 b    are 3-D views of the panel system on a base pivot (horizontal axis), illustrating that aligning the side and/or top of the panel directly to the sunray (e.g. south) allows sunlight to reach both sides of the panel equally with examples of either plant holders ( 1   a ) or algae tubes ( 1   b ). 
           [0018]      FIG. 2  is a 3-D side view of the bodies on a horizontal pivot axis aligned south and north tracking sunray movement during the sunrise, noon and sunset in a day. 
           [0019]      FIG. 3  is a 3-D side view, of the bodies on a horizontal pivot axis which aligned East and West tracking sunray movement during different seasons. 
           [0020]      FIG. 4  is a top plan view of bodies on a side-vertical pivot axis aligned south and north. 
           [0021]      FIG. 5  is a top plan view, of bodies on a central-vertical pivot axis aligned south and north. 
           [0022]      FIG. 6  is a top plan view of the body illustrating that the alternating positions of plant holders or tubes on both sides of the panel enables capture of reflected and deflected sunlight reaching to all surfaces of holders or tubes. 
           [0023]      FIGS. 7 a , 7 b  and 7 c    are end views of the panel on a horizontal pivot axis, illustrating that adjusting the degree of tapering on the panel allow for different levels of sunlight intensity exposed on each side of the panel with an example with less desirable but equal amount of light exposure on both sides (sharper tapering,  FIG. 7 a   ), an example with higher desirable but equal amount of light exposure on both sides (gentler tapering,  FIG. 7 b   ), and an example with unequal amount of light exposures on both sides ( FIG. 7 c   ) 
           [0024]      FIGS. 8 a  and 8 b    are 3-D views showing example of arrangements of artificial lights between plant holders or tubes ( 8   a ) or placement of lights inside tubes ( 8   b ) for a hybrid light-source growing system (also refer to  FIG. 1 ). 
           [0025]      FIG. 9  is a side elevation view of weight support mechanisms coupling with actuator controller to assist movement of sun tracking growing system for photosynthetic organisms. 
           [0026]      FIG. 10  is a 3-D view that shows the adjustments of the slope for the panels (i.e. α), for example, to allow desirable alignment with the seasonal changes in sun&#39;s altitude. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    A sun tracking growing system for photosynthetic organisms, generally identified by reference numeral  10  in all figures, will now be described with reference to  FIG. 1 through 10 . When the term “plants” is used herein, it will be understood that it is used as a shorthand term to cover photosynthetic organisms generally, unless the context requires otherwise. 
         [0028]    Structure and Relationship of Parts: 
         [0029]    Retelling to  FIG. 1 a    and  FIG. 1   b,  sun tracking growing system  10  includes a body  12  with a first face  14  and a second face  16  with a peripheral connecting edge  18 . First face  14  and second face  16  are positioned in opposition to each other. Peripheral connecting edge  18  is generally small in comparison to the size of first face  14  and second face  16 . A mounting  20  is attached to body  12  which enables it to pivot about a pivot axis. Body supports plant supports  24  for receiving plants  26 . Pivot axis may be substantially horizontal, substantially vertical or angular based upon the positioning of body  12  and the motion required to track the sun. In the illustrated embodiment a substantially pivot axis is horizontal. Referring to  FIG. 2 , a sun tracking sensor  40  is provided which senses the position of the sun. Light sensors  40  are provided on each side of body  12  and sense changes in the amount of light hitting each side of the faces. It will be understood that other different methods of sun tracking may be used, including sunray tracking calculations and temperature sensors. As shown, sun tracking sensor  40  may be positioned on a single body  12   a  when an array of bodies  12   a,    12   b  and  12   c  are positioned together. It will be understood, however, that each body  12   a,    12   b  and  12   c  may have a sun tracking sensor  40 . Sun tracking sensors  40  may also be used to maintain first face  14  and second face  16  of body  12  in specific orientations to provide specific portions of sunlight to each of first face  14  and second face  16 . For example, where equal light is required by first face  14  and second face  16 , light in sensor  40  on first face  14  should remain equivalent to light in sensor  40  on second face  16 . If different light proportions are required for each of first face  14  and second face  16 , sensors  40  maintain the relative proportions of light and adjust accordingly. 
         [0030]    Referring to  FIG. 9 , as an example, control of sunlight tracking can be achieved by using an actuator  28  which receives sensing data from sun tracking sensor  40  and then adjusts its arm length so as to result in a rotational movement of supporting parallelogram frame  35 , thereby changing the orientation of body  12  about a pivot axis to maintain a selected portion of peripheral connecting edge  18  of body  12  facing the sun. A plurality of bodies  12   a,    12   b  and  12   c  may be positioned in parallel spaced relation, with each of bodies  12   a,    12   b  and  12   c  linked in movement to track the sun concurrently. Plurality of bodies  12   a,    12   b  and  12   c  are tied together on the supporting frame  35  so that all of the bodies move in unison along with the movement of parallelogram frame  35 . 
         [0031]    Referring to  FIG. 9 , the movement of body  12  along with supporting parallelogram frame  35  can be facilitated by a hydraulic or mechanical spring accumulator  30 , which assists in handling the weight of bodies  12   a,    12   b,  and  12   c  and overcoming inertia. In the embodiment shown, weights  34  can also be used in conjunction with pulleys  36  to assist in handling the weight of bodies  12   a,    12   b  and  12   c.  Referring to  FIG. 10 , pivotal mountings  20  of bodies  12   a,    12   b  and  12   c  may be positioned on a movable base  38  that can be tilted to a selected slope a using actuator controller  28 . 
         [0032]    The orientation adjustment of body  12  may occur in a number of different ways. For example, referring to  FIG. 2 , body  12  may be aligned toward the south and north and move along with the daily changes in sunray  11  such that plurality of bodies  12   a,    12   b  and  12   c  are always in parallel to sunrays  11 . This type of alignment allows for large numbers of bodies  12  to be arrayed closely together in multiple straight rows, without shading each other, and may be used anywhere but is most useful in regions close to the Earth&#39;s poles (e.g. temperate, boreal and polar regions). Referring to  FIG. 3 , it is also possible to align bodies  12   a,    12   b  and  12   c  toward east and west and adjust along with both seasonal and daily changes in the sun&#39;s altitude to maintain bodies  12   a,    12   b  and  12   c  in parallel to sunrays  11 . This type of alignment also allows for large numbers of bodies  12  to be arrayed closely together in multiple straight rows, without shading each other, and may be used anywhere but is most useful in regions close to the Earth&#39;s equator (e.g. subtropical and tropical regions). 
         [0033]    There are a number of ways in which pivot axis of body  12  may be set up. For example, referring to  FIGS. 2 and 3 , body  12  may be set up on a substantially horizontal pivot axis. A substantially horizontal pivot axis allows for large numbers of bodies  12  to be arrayed closely together in multiple rows without shading each other. Referring to  FIGS. 4 and 5 , on the other hand, bodies  12   a,    12   b  and  12   c  may be set up on a substantially vertical pivot axis. With a vertical pivot axis, however, multiple rows of bodies  12  cannot he arrayed closely together without creating shadows from the first row over the subsequent row(s). 
         [0034]    Referring to  FIG. 1   a,  body  12  may include plant supports  24  within frame  32  or referring to  FIG. 1   b,  body  12  may include a plurality of cylindrical tubes  44  containing liquid nutrients within frame  32 . Plant supports  24  or cylindrical tubes  44  may be positioned in spaced relation along one of a width or length of frame  32 . Referring to  FIG. 6 , plant supports  24  or cylindrical tubes  44  may also be staggered so that they are alternatively positioned toward first face  14  and then toward second face  16 . This orientation of plant supports  24  allows sunlight  11  to reach all sides of plant supports  24 . 
         [0035]    Referring to  FIG. 7 a , 7 b , 7 c   , body  12  is preferably wedge-shaped with the thin edge of the wedge being the peripheral connecting edge  18  of body  12 . Peripheral connecting edge  18  of body  12  is maintained facing the sun as the movement of the sun is tracked. Referring to  FIG. 2 , first face  14  and second flee  16  of body  12  are preferably rectangular or S square with four sides or can be in an shape. Referring to  FIG. 7 a , 7 b , 7 c   , the relative angle of first face  14  to second face  16  determines sun exposure. The greater the angle, the greater the exposure to sunlight  11 . For example, plants supported by body  12  as illustrated in  FIG. 7 b   , receive greater exposure to sunlight  11 , as compared to plants supported by body  12  as illustrated in  FIG. 7 a   . Referring to  FIG. 7 a    and  FIG. 7 b   , first face  14  and second face  16  may define an equilateral triangle, so that first face  14  and second face  16  receive equal exposure to sunlight  11 . However, referring to FIG,  7   c,  the angle of first face  14  and second face  16  may be unequal so that first face  14  and second face  16  receive unequal exposure to sunlight  11 . This allows for different plants that require different levels of sun exposure to be positioned on opposite faces of the same body  12 . 
         [0036]    Referring to  FIG. 8 a    and  FIG. 8 b   , an artificial light source  46  may be supported by body  12  to provide artificial light to plant supports  24  or cylindrical tubes  44 , when sunlight is not available. Artificial light source  46  may be in the form of fluorescent lights or any other type of light suitable for providing artificial light. The artificial light sources  46  may also be placed in a number of different ways, such as inside of tubes  44 . 
         [0037]    Operation: 
         [0038]    Referring to  FIG. 7 a , 7 b , 7 c   , body  12  for sun tracking growing system  10  is selected to suit the variety of plant being grown. Referring to  FIG. 7 a   , plants that have sunlight sensitivities are positioned along first flee  14  and second face  16  of body  12  with a sharper tapering. Referring to  FIG. 7 b   , plant that require greater exposure to the sunlight  11  are placed along first face  14  and second face  16  of body  12 , where first face  14  and second face  16  are angled outwardly at a greater angle. If the angles are equal, first face  14  and second face  16  will receive equal exposure to sunlight  11 . This is suitable when body  12  is supporting a single variety of plant or varieties of plants that require similar exposure to sunlight  11 . Referring to  FIG. 7 c   , if the angles are not equal, first face  14  and second face  16  will receive different amounts of sun exposure or sunlight  11 . This allows a single body  12  to have plants with different sun exposure requirements present on each of first face  14  and second face  16 . 
         [0039]    Referring to  FIG. 1 a    and  FIG. 1   b,  body  12  has mounting  20  which pivots along a pivot axis. Pivot axis may be substantially vertical, substantially horizontal or any angle based upon the positioning of body  12  and the motion required to track the sun. For example, referring to  FIGS. 2 and 3 , body  12  may be set up on a substantially horizontal pivot axis. A substantially horizontal pivot axis allows for large numbers of bodies  12  to be arrayed in multiple rows closely together without creating shadows to each other. Referring to  FIGS. 4 and 5 , body  12  may also be set up on a substantially vertical pivot axis. However, bodies  12  on a vertical pivot axis, which may be easier to be built and controlled, cannot be arrayed in multiple rows closely together as the front row will create shadows on the subsequent rows. Plants are placed into plant supports  24  that are supported by body  12 . In the embodiments shown, plant supports  24  may support plant pots as shown in  FIG. 1 a    or cylindrical tubes  44  containing liquid nutrients as shown  FIG. 1   b.  It will be understood that the plant supports  24  may be of any shape or size. The tubes  44  containing liquid nutrients are just one of many ways suited for growing photosynthetic organisms such as algae Which grow in liquid media. 
         [0040]    Referring to  FIG. 2 , sun tracking sensor  40  is provided which senses the position of the sun. Referring to  FIG. 9 , a controller  28  is provided which receives sensing data from sun tracking sensor  40  and then adjusts its arm length, resulting in a rotational movement of supporting frame  35 , thereby changing the orientation of body  12  about a pivot axis to maintain a selected portion of peripheral connecting edge  18  of body  12  facing the sun. Referring to  FIGS. 2-5 , the manner in Which body  12  moves when tracking the sun is illustrated. A plurality of bodies  12   a,    12   b  and  12   c  may be positioned in parallel spaced relation in one row or multiple rows, with all bodies or rows linked in movement to track the sun in unison. Referring to  FIG. 9 , the movement of body  12  along with supporting parallelogram frame  35  is facilitated by a hydraulic or mechanical spring accumulator  30 , Which assists in handling the weight of bodies  12   a,    12   b,  and  12   c  and overcoming inertia. Weights  34  can also be used in conjunction with pulleys  36  to assist in handling the weight of bodies  12   a,    12   b  and  12   c.  Bodies  12   a,    12   b  and  12   c  are connected together by parallelogram frame  35  so that bodies  12   a,    12   b  and  12   c  move together when the frame  35  is moved rotationally. Referring to  FIG. 10 , pivotal mountings  20  of bodies  12   a,    12   b  and  12   c  may be positioned on a movable base  38  that can be tilted to a selected slope a using actuator controller  28 . 
         [0041]    Referring to  FIG. 8 a    and  FIG. 8 b   , an artificial light source  46  may be supported. by body  12  to provide artificial light to plants supports  24  or cylindrical tubes  44  supported on body  12  when sunlight is not available. The number of light sources  46  and the intensity of light source  46  are dependent upon the requirements of the plants  26  being supported by body  12 . The artificial light sources  46  may also be placed inside tubes  44 . 
         [0042]    In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. 
         [0043]    The following claims are to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, and what can be obviously substituted. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.