Apparatus for tracking solar radiation

Abstract

The tracking apparatus ( 2 ) comprises a frame ( 4 ) mounted on a rigid stand that is orientated such that the longitudinal axis ( 6 ) of the frame is at an angle above horizontal. The frame ( 4 ) comprises opposite frame members ( 8 and 10 ) between which is mounted reservoirs in the form of hollow side tanks ( 12 and 14 ). Each of the tanks is partially filled with a liquid refrigerant. The interior of the tank ( 12 ) is connected to flexible bellows ( 16 ) through the passageway of a conduit ( 18 ). The interior of the tank ( 14 ) is connected to flexible bellows ( 20 ) through the passageway of a further conduit ( 22 ). An actuating mechanism ( 24 ) is secured to frame member ( 10 ) of the frame. The actuating mechanism comprises a further frame ( 26 ) to which the outer ends of bellows ( 16 and 20 ) are fastened. The inner ends of the bellows are connected by a rigid shaft ( 28 ) which is driven back and forth by the bellows ( 16 and 20 ) to effect rotation of drive wheel ( 30 ) of the actuating mechanism. The drive wheel is fixedly secured to an inner axle ( 32 ) comprising output drive means and defining the longitudinal axis ( 6 ), such that rotation of the drive wheel rotates the inner axle. The inner axle is received within an outer axle ( 34 ) extending through the opposite frame members of ( 8 and 10 ) of the frame ( 4 ) of the tracking apparatus. First shade means comprising an elongate shade ( 36 ) and opposite inner and outer shade arms ( 38 and 40 ), to which the shade ( 36 ) is fixed, is mounted on the inner axle ( 32 ). The outer shade arm ( 40 ) is fixed to the drive wheel ( 30 ) for rotation of the shade with the drive wheel and the inner axle. Second shade means comprising a further elongate shade ( 42 ) lying parallel with respect to tank ( 14 ) and opposite inner and outer shade arms ( 44 and 46 ) to which that shade is fixed, is mounted on the outer axle ( 34 ). As the sun rises, tank ( 12 ) is progressively shaded by shade panel ( 36 ) while tank ( 14 ) is heated by the solar radiation. The pressure of the refrigerant in tank ( 12 ) thereby decreases and the resulting differential refrigerant pressure between tank ( 12 ) and tank ( 14 ) causes bellows ( 20 ) to partially extend and bellows ( 16 ) to partially contract. The extension of bellows ( 20 ) and contraction of bellows ( 16 ) drives shaft ( 28 ) laterally forcing the ever arm ( 48 ) of the actuating mechanism to pivot about pivot pin ( 50 ) and the drive wheel ( 30 ) to rotate. The rotation of the drive wheel raises shade ( 36 ) in a westerly direction exposing tank ( 12 ) to the incident solar radiation. Both of the tanks are thereby heated equally once more, and the refrigerant pressure in the tanks equalises stopping rotation of the drive wheel.

1 . A tracking apparatus for tracking solar radiation from the sun, the device comprising:
 first shade means rotatable about an axis of rotation;   second shade means rotatable about the axis of rotation;   a first reservoir for a fluid and which is arranged to one side of the axis of rotation;   a second reservoir for a fluid and which is arranged to an opposite side of the axis of rotation;   an actuating mechanism for rotating the first shade means about the axis of rotation;   a driving mechanism disposed for fluid communication with the fluid in the first reservoir and the fluid in the second reservoir, for driving the actuating mechanism to effect the rotation of the first shade means about the axis of rotation in one direction with the heating of the second reservoir by the solar radiation and in an opposite direction about the axis of rotation with heating of the first reservoir by the solar radiation; and   output drive means adapted for being coupled to a solar device to synchronously rotate the solar device with the first shade means when the first shade means is rotated in the one direction for tracking of the solar radiation by the solar device;   wherein the first shade means is arranged for progressive rotation in the one direction to shade the first reservoir with the heating of the second reservoir by the solar radiation, and the second shade means is arranged for rotation in the one direction from an initial position with the first shade means to a final position for shading the second reservoir during a further daylight period to effect return of the first shade means and the second shade means in the opposite direction with heating of the first reservoir by the solar radiation during the further daylight period.   
   
   
       2 . A tracking apparatus according to  claim 1  wherein said driving mechanism comprises first drive means responsive to the heating of the first reservoir by the solar radiation, second drive means responsive to heating of the second reservoir by the solar radiation, and a drive member arranged for being driven back and forth by the first drive means and the second drive means to drive the actuating mechanism. 
   
   
       3 . A tracking apparatus according to  claim 2  wherein the first drive means and the second drive means comprise respective bellows alternatively operable relative to one another. 
   
   
       4 . A tracking apparatus according to  claim 2  wherein the actuating mechanism comprises a lever arm pivotable about a pivot axis and a drive wheel for driving the first shade means about the axis of rotation with rotation of the drive wheel, the lever arm being arranged to be driven about the pivot axis by the drive member of the driving mechanism to drive the rotation of the drive wheel. 
   
   
       5 . A tracking apparatus according to  claim 1  wherein the tracking apparatus further comprises a stop for stopping rotation of the second shade member about the axis of rotation in the one direction beyond the final position, the first shade member being free to continue to rotate in the one direction when the second shade is in contact with the stop. 
   
   
       6 . A tracking apparatus according to  claim 1  wherein the second shade means rests on the first shade means when the second shade means is in the initial position and is adapted to rotate about the axis of rotation under the effect of gravity from the initial position to the final position with the rotation of the first shade means about the axis of rotation in the one direction, and wherein the second shade means is driven about the axis of rotation in the opposite direction by the first shade means. 
   
   
       7 . A tracking apparatus according to  claim 1  wherein the output drive means comprises an inner axle defining the axis of rotation and the first shade means is mounted on the axle whereby the axle rotates with the first shade member. 
   
   
       8 . A tracking apparatus according to  claim 7  further comprising an outer axle receiving the inner axle, the second shade means being mounted on the second axle. 
   
   
       9 . A tracking apparatus according to  claim 1  wherein the tracking apparatus comprises a frame to which the first reservoir and the second reservoir are mounted, wherein the frame is adapted for being held in a fixed position during operation of the tracking apparatus. 
   
   
       10 . A tracking apparatus according to  claim 1  wherein the solar device comprises a solar panel. 
   
   
       11 . A tracking apparatus according to  claim 10  wherein the solar panel comprises photovoltaic cells for generating electricity. 
   
   
       12 . A tracking apparatus according to  claim 10  wherein the solar panel comprises a reflector for being rotated by the output drive means of the tracking apparatus for maintaining reflection of the solar radiation on a target object or space during the passing of the daylight period. 
   
   
       13 . A tracking apparatus for tracking solar radiation from the sun, comprising:
 a solar device arranged for being exposed to the solar radiation;   first shade means rotatable about an axis of rotation;   second shade means rotatable about the axis of rotation;   a first reservoir for a fluid and which is arranged to one side of the axis of rotation;   a second reservoir for a fluid and which is arranged to an opposite side of the axis of rotation;   an actuating mechanism for rotating the first shade means about the axis of rotation;   a driving mechanism disposed for fluid communication with the fluid in the first reservoir and the fluid in the second reservoir, for driving the actuating mechanism to effect the rotation of the first shade means about the axis of rotation in one direction with the heating of the second reservoir by the solar radiation and in an opposite direction about the axis of rotation with heating of the first reservoir by the solar radiation; and   output drive means for driving rotation of the solar device synchronously with the rotation of the first shade means when the first shade means is rotated in the one direction for tracking of the solar radiation by the solar device;   wherein the first shade means is arranged for progressive rotation in the one direction to shade the first reservoir with the heating of the second reservoir by the solar radiation, and the second shade means is arranged for rotation in the one direction from an initial position with the first shade means to a final position for shading the second reservoir during a further daylight period to effect return of the first shade means and the second shade means in the opposite direction with heating of the first reservoir by the solar radiation during the further daylight period.   
   
   
       14 . A tracking apparatus according to  claim 13  wherein the daylight period in which the first shade means is rotated in the one direction is on one day and the further period in which the first shade means is rotated in the opposite direction is a morning period of the next day. 
   
   
       15 . A tracking apparatus according to  claim 13  wherein the fluid is a refrigerant. 
   
   
       16 . A tracking apparatus for tracking solar radiation from the sun, the device comprising:
 first shade means rotatable about an axis of rotation;   second shade means rotatable about the axis of rotation;   a first reservoir for a fluid and which is arranged to one side of the axis of rotation;   a second reservoir for a fluid and which is arranged to an opposite side of the axis of rotation;   a driving mechanism disposed for fluid communication with the fluid in the first reservoir and the fluid in the second reservoir, for effecting rotation of the first shade means about the axis of rotation, a direction of rotation being dependent upon relative heating differences between the first and second reservoirs; and   output drive means adapted for being coupled to a solar device to synchronously rotate the solar device with the first shade means;   wherein the first and second shade means are arranged so as to cast a shading sequence onto the first and second reservoirs such that during a first daylight period the first shade means is driven by the driving mechanism so as to track incident solar radiation and during a further daylight period the first and second shade means are returned to respective initial positions.   
   
   
       17 . A tracking apparatus according to  claim 16  wherein the first daylight period is on one day and the further daylight period is a morning period of the next day.