Temperature control for a solar collector

Abstract

A solar collector temperature control intended for use with a solar collector comprising at least one solar tube ( 11 ), the interior of the solar tube in use accommodating a heat exchanger or a like means and/or heat exchange medium, said temperature control comprising a controller and a shield ( 19 ), the shield associated with the outer wall of the solar tube and extending for at least a portion of the length of the solar tube, said shield having an angular extent sufficient to extend partially around the solar tube. The shield supported to be rotatable about the central axis of the solar tube between a first position remote from the source of radiation and a second position most proximate the source of radiation. The control further comprising a sensor adapted to sense the temperature of the a heat exchanger or a like means and/or heat exchange medium accommodated by the solar tube, a drive ( 21, 25, 29 ) operatively controlled by the controller to cause rotation of the shield around the central axis of the solar tube between the first and second position depending upon the temperature of the heat exchanger or like means and/or medium accommodated within the interior of the solar tube.

1 . A solar collector temperature control intended for use with a solar collector, said solar collector comprising at least one solar tube, the interior of the solar tube in use accommodating a heat exchanger or a like means and/or heat exchange medium, said temperature control comprising a controller and a shield, the shield associated with the outer wall of the solar tube and extending for at least a portion of the length of the solar tube, said shield having an angular extent sufficient to extend partially around the solar tube, the shield supported to be rotatable about the central axis of the solar tube between a first position remote from the source of radiation and a second position most proximate the source of radiation, the control further comprising a sensor adapted to sense the temperature of the a heat exchanger or a like means and/or heat exchange medium accommodated by the solar tube, a drive operatively controlled by the controller to cause rotation of the shield around the central axis of the solar tube between the first and second position depending upon the temperature of the heat exchanger or like means and/or medium accommodated within the interior of the solar tube. 
     
     
         2 . A solar collector temperature control as claimed at  claim 1  wherein the shield is supported to be rotatable about the central axis of the solar tube to a range of positions including a first position remote from the source of radiation and a second position most proximate the source of radiation. 
     
     
         3 . A solar collector temperature control as claimed at  claim 1  wherein the angular extent of the shield is approximately 180°. 
     
     
         4 . A solar collector temperature control as claimed at  claim 1  wherein the shield extends for substantially the full length of the solar tube. 
     
     
         5 . A solar collector temperature control as claimed at  claim 1  wherein the outer face of the shield is reflective of solar radiation. 
     
     
         6 . A solar collector temperature control as claimed at  claim 1  wherein the inner face of the shield is reflective of solar radiation. 
     
     
         7 . A solar collector temperature control as claimed at  claim 1  wherein the shield comprises an elongate member which is supported in parallel relationship to the tube to be concentrically rotatable around the central axis. 
     
     
         8 . A solar collector temperature control as claimed at  claim 7  wherein the shield is supported to be angularly displaceable relative to the solar tube. 
     
     
         9 . A solar collector temperature control as claimed at  claim 7  wherein the shield is supported from the solar tube and wherein the solar tube is supported to be angularly displaceable about the central axis. 
     
     
         10 . A solar collector temperature control as claimed at  claim 7  wherein the operative connection to the drive comprises a toothed formation provided in association with the shield, said toothed formation being engaged with a threaded pinion which is caused to rotate to cause the rotation of the shield. 
     
     
         11 . A solar collector temperature control as claimed at  claim 7  wherein the operative connection to the drive comprises a toothed formation provided in association with the solar tube, said toothed formation being engaged with a threaded pinion which is caused to rotate to cause the rotation of the solar tube. 
     
     
         12 . A solar collector temperature control as claimed at  claim 1  wherein the shield is supported from the solar tube from at least one location along the length of the solar tube and wherein said solar tube is supported to be rotatable about its central axis, said drive being operatively connected to the solar tube to cause said rotation. 
     
     
         13 . A solar collector temperature control as claimed at  claim 12  wherein the shield is supported from one end portion of the tube. 
     
     
         14 . A solar collector temperature control as claimed at  claim 12  wherein the shield is supported from at least each end portion of the tube. 
     
     
         15 . A solar collector temperature control as claimed at  claim 1  wherein the shield comprises a portion of the outer wall on the solar tube which is treated to be opaque to solar radiation and wherein said solar tube is supported to be rotatable about its central axis said drive being operatively connected to the solar tube to cause said rotation. 
     
     
         16 . A solar collector temperature control as claimed at  claim 15  wherein the shield comprises a coating which is applied to the solar tube. 
     
     
         17 . A solar collector temperature control as claimed at  claim 16  wherein the coating comprises a tape which is adhered to the solar tube. 
     
     
         18 . A solar collector temperature control as claimed at  claim 17  wherein the coating comprises a film applied to the solar tube. 
     
     
         19 . A solar collector temperature control as claimed at  claim 9  wherein the operative connection to the drive comprises a toothed formation provided in association with the solar tube. 
     
     
         20 . A solar collector temperature control as claimed at  claim 19  wherein the toothed formation is associated with a hub element which is grippingly received over one end of the solar tube. 
     
     
         21 . A solar collector temperature control as claimed at  claim 20  wherein the hub element is rotatably received in a housing which accommodates the drive. 
     
     
         22 . A solar collector temperature control as claimed at  claim 20  wherein the one end of the solar tube is the closed end. 
     
     
         23 . A solar collector temperature control as claimed at  claim 20  wherein the one end of the solar tube is the open end. 
     
     
         24 . A solar collector temperature control as claimed at  claim 20  wherein the hub element comprises a moulded element having an internal configuration complementary to the one end and the toothed formation is formed around the outer surface of the hub element. 
     
     
         25 . A solar collector temperature control as claimed at  claim 19  wherein the drive comprises a toothed sprocket provided on a drive shaft and said toothed formation is provided by a further toothed sprocket said drive further comprising an endless chain which drivingly interconnects the sprockets. 
     
     
         26 . A solar collector temperature control as claimed at  claim 1  wherein the drive includes an element which is subjected to the temperature conditions which are representative of the temperature conditions of the heat exchanger or like means and/or medium accommodated within the interior of the solar tube and wherein the element will undergo longitudinal expansion and contraction resulting from temperature change. 
     
     
         27 . A solar collector temperature control as claimed at  claim 1  wherein the drive includes an electric motor. 
     
     
         28 . A solar collector temperature control as claimed at  claim 27  wherein the electrical power to the electrical motor is derived from a photoelectric device. 
     
     
         29 . A solar collector temperature control as claimed at  claim 28  wherein the photoelectric device is connected to an electrical storage battery which and the motor is driven from the battery and/or the photoelectric device. 
     
     
         30 . (canceled) 
     
     
         31 . A solar collector temperature control as claimed at  claim 12  wherein the operative connection to the drive comprises a toothed formation provided in association with the solar tube.