Low cost one axis solar tracking operated by water pressure

Abstract

The scope of this study is to design a simple & low cost solar tracking system, which make uses downward movement of a piston cause by controlled discharge of water from water filled cylinder. The solar panels are mounted on the lever and when the lever rotates, the panels also rotate by the same angle, which is required. Rotation is done by connecting two pistons to the frame of panel via two links. In the method describe here. PV panel is mounted on a frame that pivot on an axis running from South to north with a slight inclination towards the north. As the sun moves from the morning to afternoon, the PV panel is rotated around the axis to make it normal to the Sun's rays as far as possible. The rotation is not done continuously since it will drain some of the solar energy collected with great difficulty. Instead, the rotation is done intermittently./ The tracking is activated by the controlled discharge of water from water filled cylinder. When water is discharged by a controlled rate, the piston on top of water column moves down. The downward motion of piston is then converted to a rotary motion of the frame around the pivot axis by means of two links. The discharge of water is controlled by an electronic circuit, which gets signals from two sensors mounted on the lever. There is an opaque screen normal to the PV panel and between the light sensors. When the incident solar rays are normal to the lever, the two sensor readings arc equal. When it is not so. The difference of the two signals from the sensors is fed to an electronic circuit which opens the discharge valve of the water cylinder causing the piston to go dow n and rotate the frame w ith solar panel. When the solar panel is rotated in the correct direction by the required amount, the sensors generate the same readings and the electronic circuit stops the water discharge./ Test on this tracking system shows that the total power output of the solar panel can be increase by about 25 % on a sunny day. On a cloud} day . because of the diffused radiation the tracking is not that much advantage, and this is true for other tracking systems as well. It is expected that this low cost one axis tracking system would pave the w ay for future research to increase of solar energy output in a sunny day by employing reflectors fixed to the frame and rotating together.