Transaction on Energy, biotechnology, planning and Environment ISSN: 2229-8711 Online Publication, June 2011 www.pcoglobal.com/gjto.htm ET-E33/GJTO Copyright @ 2011/gjto IMPLEMENTATION OF DUAL-AXIS SOLAR TRACKING PILOT PROJECT Nader Barsoum Curtin University, Sarawak, Malaysia Email: nnb3@hotmail.com Received December 2010, Revised January 2011, Accepted March 2011 Abstract The recent decades have seen the increase in demand for reliable and clean form of electricity derived from renewable energy sources. One such example is solar power. The challenge remains to maximize the capture of the rays from the sun for conversion into electricity. This paper presents the steps of implementing a dual-axis solar tracking controller. This is done so that rays from the sun fall perpendicularly unto the solar panels to maximize the capture of the rays by pointing the solar panels towards the sun and following its path across the sky. Thus electricity and efficiency increased. Keywords: Controller, tracker, sensor, battery, inverter, timer, switches, program, installation 1. Introduction Electrical energy from solar panels is derived by converting energy from the rays of the sun into electrical current in the solar cells. The main challenge is to maximize the capture of the rays of the sun upon the solar panels, which in turn maximizes the output of electricity. A practical way of achieving this is by positioning the panels such that the rays of the sun fall perpendicularly on the solar panels by tracking the movement of the sun [1]. This can be achieved by means of using a solar panel mount which tracks the movement of the sun throughout the day. Energy conversion is most efficient when the rays fall perpendicularly onto the solar panels. Thus, the work is divided into three main parts namely the mounting system, the tracking controller system and the electrical power system. In solar tracking systems, solar panels are mounted on a structure which moves to track the movement of the sun throughout the day. There are three methods of tracking: active, passive and chronological tracking. These methods can then be configured either as single-axis or dual-axis solar trackers. In active tracking, the position of the sun in the sky during the day is continuously determined by sensors. The sensors will trigger the motor or actuator to move the mounting system so that the solar panels will always face the sun throughout the day. This method of sun-tracking is reasonably accurate except on very cloudy days when it is hard for the sensor to determine the position of the sun in the sky thus making it hard to reorient the structure [2]. Passive Tracking unlike active tracking which determines the position of the sun in the sky, a passive tracker moves in response to an imbalance in pressure between two points at both ends of the tracker. The imbalance is caused by solar heat creating gas pressure on a ‘low boiling point compressed gas fluid that is driven to one side or the other’ [2] which then moves the structure. However, this method of sun-tracking is not accurate. A chronological tracker is a timer-based tracking system whereby the structure is moved at a fixed rate throughout the day. The theory behind this is that the sun moves across the sky at a fixed rate. Thus the motor or actuator is programmed to continuously rotate at a ‘slow average rate of one revolution per day (15 degrees per hour)’ [2]. This method of sun-tracking is very accurate. However, the continuous rotation of the motor or actuator means more power consumption and tracking the sun on a very cloudy day is unnecessary. A single-axis solar tracker follows the movement of the sun from east to west by rotating the structure along the vertical axis. The solar panels are usually tilted at a fixed angle corresponding to the latitude of the location. According to [3], the use of single-axis tracking can increase the electricity yield by as much as 27 to 32 percent. On the other hand, a dual-axis solar tracker follows the angular height position of the sun in the sky in addition to following the sun’s east-west movement [3] reports that dual-axis tracking increases the electricity output as much as 35 to 40 percent. 2. Description The primary task of this pilot project is to build an actual solar panel mount with a sun-tracking system to be installed outdoors in Miri (location: 4°23ƍ35ƎN 113°58ƍ49ƎE) in Sarawak, Malaysia. Based on the background information of the various types of solar trackers, it has been decided that active tracking with a dual-axis set-up will be used. The reason for this choice is active tracking is a fairly effective method to track the sun and a dual-axis tracking system has the capability of increasing the yield of electrical energy output from the solar panels. For the purpose of clarity, the east-west of the tracker will be called the “horizontal tracking” while the angular height tracker will be referred to as “vertical tracking”. An active, dual-axis tracking system prototype has already been designed and built by [4], which consists of the sensor system to determine the position of the sun and a controller system which reads data from the sensors to command the movement of the tracker. A program to control the tracking system has been also developed [4]. The sensor system consists of two sensors: one to determine the position of the sun in the sky and another to determine the position of the sun’s movement from east to west.