RELATED APPLICATIONS
The present application is based on, and claims priority from Taiwan Application Serial Number 096138763, filed Oct. 17, 2007, the entire disclosure of which is incorporated by reference herein.
TECHNICAL FIELD
This disclosure relates to a sun tracking system for a solar panel that collects and converts solar energy into electricity or heat. More specifically, this disclosure relates to a sun tracking system based on pressure difference.
BACKGROUND
FIG. 1 Prior Art
FIG. 1 shows a solar panel 105 having a conventional sun tracking system. The tracking system comprises four photo sensors 101,102,103,104 encircled by a sleeve 120. The four sensors are located in the center of the top surface of the solar panel 105. Photoelectric units 108 for collecting and converting solar energy into electricity are distributed on the top surface of the solar panel 105. The sleeve 120 has an opening for detecting the direction and/or movement of the sun through detecting the light intensity irradiating on each of the sensors. The traditional sleeve 120 has a wall with even height erected from the surface of the solar panel 105.
When the sun is above the solar panel 105, the light rays from the sun irradiate directly onto the solar panel 105, each of the four photo sensors is presumed to receive equal heat strength, or light intensity, from the sun. However, when the sun shifts sideways, e.g., left as shown in FIG. 1, the light rays below R1 are hindered by the wall and prevented from reaching some or all of the photo sensors 101,102,103,104. A shadow is produced within the sleeve under R1, the shadow will cover wholly or partially the photo sensors, and hence, the light intensities sensed by the photo sensors are different from one another. FIG. 1 shows that sensor 101 is fully covered by the shadow, and sensors 102, 104 are partially covered by the shadow.
The light intensity sensed by each of the photo sensors is transferred to a control unit (not shown). A mechanism deflects the solar panel 105 a calculated angle according to the information received from the control unit so that the solar panel 105 moves synchronically with the movement of the sun to receive a relatively optimal amount of solar energy.
The drawback of the prior art shown in FIG. 1 is that the environmental light intensity sensed by photo sensor 101 is slightly higher then the actual light intensity in the shadow due to light reflection noise. In FIG. 1, e.g., a light ray R2 incident on the wall surface inside the sleeve 120 is reflected to produce a reflection light ray that is directed toward the sensor 101 to offset partially the light intensity under the shadow covering the sensor 101, and thus, increase the light intensity sensed by sensor 101.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1. shows a prior art device.
FIG. 2. shows a first embodiment of this invention.
FIG. 3. shows a second embodiment of this invention.
FIG. 4. shows a third embodiment of this invention.
FIG. 5. shows a block diagram of embodiments of this invention.
DETAILED DESCRIPTION
FIG. 2. shows a first embodiment of this invention.
In a sun tracking system with a pressure differential driving system for a solar panel 105: a first pressure tank 201 is located on a first side of the solar panel 105 to provide a first pressure; a second pressure tank 202 is located on a second side, e.g., opposite to the first side of the solar panel 105 to provide a second pressure; a first wall 211 is located beside the first pressure tank 201; a second wall 212 is located beside the second pressure tank 202; and a control system 26 is coupled to the two pressure tanks 201, 202 to adjust the solar panel 105 according to a pressure difference between the two pressure tanks 201, 202.
When the sun is above the solar panel 105, each of the photoelectric units 108 receives equal light intensity from the sun. However, when the sun shifts sideway, e.g., left as shown in FIG. 2, the shadow of the wall 212 gradually covers the second pressure tank 202 and therefore prevents the sun light from shining on the second pressure tank 202. However, there is no influence to the first pressure tank 201.
The pressure tank 201, 202 is filled with a fluid, e.g., a coolant. The coolant generates a gas pressure in the pressure tank proportionately with the environmental temperature. The gas pressures are equal when the two pressure tanks receive equal light intensity. However, a pressure difference is created between the two pressure tanks 201, 202 due to the shadow of the wall 211, 212 when the sun shifts.
A control unit 26 is coupled to the first pressure tank 201 with a first pipe 241 and to the second pressure tank 202 with a second pipe 242. The control unit 26 adjusts the solar panel 105 to track the sun movement according to the pressure difference generated between the two pressure tanks 201, 202.
FIG. 3. shows a second embodiment of this invention.
FIG. 3 shows that the control unit 26 shown in FIG. 2 can be implemented with a pressure difference driven device 23 and an adjusting structure 25. The pressure difference driven device 23 has a first cylinder 231 coupled to the first gas pressure tank 201, a second cylinder 232 coupled to the second gas pressure tank 202. The first cylinder 231 has a pressure equal to that of the first pressure tank 201. The second cylinder 232 has a pressure equal to that of the second pressure tank 202. The cylinders 231, 232 are mechanically coupled to a driven rod 233. The driven rod 233 is still when there is no pressure difference between the two cylinders 231, 232. A pull force can be generated to the driven rod 233 if the pressure of the first cylinder 231 is greater than the pressure of the second cylinder 232, and vice versa, a push force can be generated to the driven rod 233 if the pressure of the first cylinder 231 is smaller than the pressure of the second cylinder 232. The pull or push force is then transferred to adjust or rotate the solar panel 105 through the adjusting structure 25.
FIG. 4. shows a third embodiment of this invention.
FIG. 4 shows a pressure valve 27 coupled to the pipe 241 for adjusting the pressure of the coolant flow.
FIG. 5. shows a block diagram of embodiments of this invention.
FIG. 5 shows that a first coolant tank 201 generates a first pressure; a second coolant tank 202 generates a second pressure. The first pressure and the second pressure are coupled to a control system 26 for detecting the difference of the two pressures. The control system 26 is coupled to a driving structure to adjust the solar panel 105 according to the pressure difference of the two pressures.
While several embodiments have been described by way of example, it will be apparent to those skilled in the art that various modifications may be made in the embodiments without departing from the spirit of the present invention. Such modifications are all within the scope of the present invention, as defined by the appended claims.
Patent Application
20090101137
