Solar Collector

Abstract

The invention is a solar powered heat exchanger ( 10 ) comprising a solar collector ( 12 ), a heat accumulator ( 14 ), and a heat exchanger ( 16 ). The solar collector is operatively coupled to the heat accumulator ( 14 ) via a supply line ( 18 ) and a recirculation line ( 20 ). The heat accumulator ( 14 ) is in turn operatively coupled to the heat exchanger ( 16 ) via a feed line ( 22 ) and a return line ( 24 ).

1 . A solar collector comprising:
 a collector housing having a translucent or transparent surface and being sealed to permit at least partial evacuation or reduction in pressure within the housing below atmospheric pressure;   a collector tank located within the collector housing and having a solar absorbent surface located adjacent the translucent or transparent surface, the collector tank being adapted to contain a heat transfer fluid which, on exposure of the solar collector to sunlight, is heated via solar energy which penetrates the translucent or transparent surface and, with the increased efficiency provided by the sealed and at least partially evacuated housing, is absorbed onto the solar absorbent surface which transfers heat to the heat transfer fluid; and   an adjustable mounting assembly to which the collector housing is mounted, the mounting assembly being adapted to provide reorientation of the solar collector to increase exposure of the absorbent surface to sunlight.   
   
   
       2 . A solar collector as defined in  claim 1  wherein the sealed collector housing defines a chamber between at least the translucent or transparent surface and the absorbent surface of either of the collector tank. 
   
   
       3 . A solar collector as defined in  claim 1  wherein either of the housing includes an evacuation valve which permits evacuation of the sealed chamber for drawing at least a partial vacuum within the chamber. 
   
   
       4 . A solar collector as defined in  claim 1  wherein the sealed chamber surrounds the collector tank which is separated from the collector housing on opposing internal surfaces by flexible spacers. 
   
   
       5 . A solar collector as defined in  claim 1  wherein the adjustable mounting assembly effects seasonal reorientation of the solar collector by rotation about a first axis. 
   
   
       6 . A solar collector as defined in  claim 5  wherein the adjustable mounting assembly is effective in tracking the sun by pivoting about a second axis arranged generally transverse to the first axis. 
   
   
       7 . A solar collector as defined in  claim 6  wherein the first axis is the altitude axis and the second axis the azimuth axis. 
   
   
       8 . A solar collection as defined in  claim 1  wherein the heat transfer fluid is a liquid including glycol or a water/glycol mixture. 
   
   
       9 . A solar powered heat exchanger comprising:
 a solar collector including a collector housing having a translucent or transparent surface, the collector housing being sealed to permit at least partial evacuation or reduction in pressure within the housing below atmospheric pressure, and a collector tank located within the collector housing and being adapted to contain a heat transfer fluid;   a heat accumulator operatively coupled to the solar collector for storing the heat transfer fluid heated by exposure of the solar collector to sunlight wherein solar energy penetrates the translucent or transparent surface and, with the increased efficiency provided by the sealed and at least partially evacuated housing, is absorbed onto the solar absorbent surface which transfers heat to the heat transfer fluid; and   a heat exchanger operatively coupled to the heat accumulator and being arranged for transferring heat to an external device utilising the heat of the heat transfer fluid from the heat accumulator or the solar collector.   
   
   
       10 . A solar powered heat exchanger as defined in  claim 9  wherein the heat exchanger includes a heat exchange chamber in heat exchange communication with the external device, the heat exchanger chamber being connected to the heat accumulator via a feed line which provides the heat transfer from the accumulator. 
   
   
       11 . A solar powered heat exchanger as defined in  claim 10  wherein the heat exchange chamber is connected to the accumulator via a return line for returning the heat transfer fluid to the accumulator after said fluid has exchanged its heat with the external device. 
   
   
       12 . A solar heat powered heat exchanger as defined in  claim 10  wherein the heat exchanger also includes an expansion tank connected to the heat exchange chamber and designed to allow the heated fluid to expand as its temperature rises thus maintaining a relatively constant and low hydrostatic pressure within the heat exchanger. 
   
   
       13 . A solar powered heat exchanger as defined in  claim 11  wherein the heat exchanger further includes a pump connected to the return line to promote flow of the heat transfer fluid from the heat exchange chamber to the heat accumulator. 
   
   
       14 . A solar powered heat exchanger as defined in  claim 10  wherein the heat exchanger includes a heat exchange chimney connected to a feed line which interconnects the heat accumulator and the heat exchanger, the heat exchanger chimney being positioned within the heat exchange chamber to convey the heat transfer fluid from the heat accumulator. 
   
   
       15 . A solar powered heat exchanger as defined in  claim 9  wherein the heat accumulator includes an accumulator chimney connected to a supply line connected to the outlet of the collector tank, the accumulator chimney being positioned within the accumulator to convey the heat transfer fluid from the outlet of the collector tank. 
   
   
       16 . A solar powered heat exchanger as defined in  claim 9  also comprising a recirculation line connected between the heat accumulator and the solar collector for recirculation of the heat transfer fluid. 
   
   
       17 . A solar powered heat exchanger as defined in  claim 16  wherein the collector tank includes an inlet connected to the recirculation line, and an outlet coupled to the heat accumulator, the outlet being elevated relative to the inlet to effect a flow of the heat transfer fluid from the inlet to the outlet and recirculation of the heat transfer fluid through the recirculation line by a thermalsiphon effect at the inlet. 
   
   
       18 . A solar powered heat exchanger as defined in  claim 17  wherein the collector tank includes a plurality of internal baffle plates being arranged to support the tank and oriented to promote the flow of the heat transfer fluid from the inlet to the outlet. 
   
   
       19 . A solar powered heat exchanger as defined in  claim 9  further comprising a temperature control system operatively coupled to the heat exchanger to control the flow of the heat transfer fluid to the heat exchanger and thus the amount of heat exchanged with the external device. 
   
   
       20 . A solar powered heat exchanger as defined  claim 19  wherein the temperature control system includes a control valve connected to the feed line, and a temperature sensor connected to the external device, the temperature sensor being operatively coupled to the control valve whereby, depending on the temperature of the external device, the control valve is throttled to control the flow of the heat transfer fluid to the heat exchanger. 
   
   
       21 . A solar powered heat exchanger as defined in  claim 9  wherein the heat transfer fluid is a liquid such as glycol or a water/glycol mixture. 
   
   
       22 . A solar tracking apparatus comprising:
 a base being adapted to mount to a solar collector;   a shading member connected to the base at a fixed and predetermined angle, the shading member including a generally straight lower portion fixed to the base, and an upper portion extending from the lower portion at an obtuse angle;   a pair of light sensitive elements mounted on the base on respective opposing sides of the shading member, the upper portion of said shading member including a reflective surface on its lower face and directed toward one of the light sensitive elements; and   an actuator operatively coupled to the pair of light sensitive elements whereby in operation the light sensitive elements, dependent on their relative exposure to sunlight as controlled by the shading member, drive the actuator to effect movement of the solar collector.   
   
   
       23 . A solar tracking apparatus as defined in  claim 22  wherein the base is planar and the shading member is fixed substantially perpendicular to the planar base. 
   
   
       24 . A solar tracking apparatus as defined in  claim 22 , wherein the light sensitive elements are each in the form of a light dependent resistor. 
   
   
       25 . A solar tracking apparatus as defined in  claim 24 , wherein the solar tracking apparatus also comprises an actuator circuit including the light dependent resistors which dependent on their exposure to sunlight are configured to drive the actuator. 
   
   
       26 . A solar tracking apparatus as defined in  claim 25 , wherein the actuator circuit includes a voltage comparator having voltage inputs from the light dependent resistors and a reference voltage, respectively, whereby differential voltage applied to the inputs of the voltage comparator causes it to conduct thereby driving the actuator. 
   
   
       27 . A solar tracking apparatus as defined in  claim 26  wherein an output of the voltage comparator is connected to a transistor which is electrically coupled to and actuates a relay whereby the application of differential voltage to the comparator causes the comparator and the transistor to conduct and close the relay which in turn powers the actuator. 
   
   
       28 . A solar tracking apparatus as defined in  claim 27 , wherein the relay includes an electromagnetic relay connected to a normally-open relay contact. 
   
   
       29 . A solar tracking apparatus tracking apparatus as defined in  claim 25  wherein the actuator is in the form of a drive motor. 
   
   
       30 . A solar tracking apparatus as defined in  claim 29  wherein the drive motor is electrically coupled to the pair of light sensitive elements via the actuator circuit. 
   
   
       31 - 36 . (canceled) 
   
   
       37 . The solar collector of  claim 1  further comprising a solar tracking apparatus, the solar tracking apparatus being connected to the solar collector and designed for reorientation of the collector to optimise its exposure to sunlight wherein the solar tracking apparatus includes
 a base being adapted to mount to a solar collector;   a shading member connected to the base at a fixed and predetermined angle, the shading member including a generally straight lower portion fixed to the base, and an upper portion extending from the lower portion at an obtuse angle;   a pair of light sensitive elements mounted on the base on respective opposing sides of the shading member, the upper portion of said shading member including a reflective surface on its lower face and directed toward one of the light sensitive elements; and   an actuator operatively coupled to the pair of light sensitive elements whereby in operation the light sensitive elements, dependent on their relative exposure to sunlight as controlled by the shading member, drive the actuator to effect movement of the solar collector.   
   
   
       38 . The solar collector of  claim 37  wherein the solar tracking apparatus is arranged to rotate the solar collector about an azimuth axis to effectively track the sun and optimise daily exposure to sunlight. 
   
   
       39 . The solar collector of  claim 38  further comprising an additional solar tracking apparatus, the additional solar tracking apparatus being designed to permit rotation or tilting of the solar collector about an altitude axis to optimise its seasonal exposure to sunlight.