Using Solar Energy in Robotics and Small Scale Electronic Applications

Now, more than ever before, the use of renewable energy is critical to the well being of our planet. Solar energy, in particular, is one of the main sources of renewable energy and the subject of research worldwide. While most renewable energy projects using solar energy target large-scale applications, renewable energy technologies are also suited for small-scale applications. This is evident in hand held calculators, recreation electronics and more recently, in traffic signals. One of the main issues encountered in the renewable energy industry, particularly the solar energy arena, is the storage of the harvested energy. The conventional method is by using batteries. Batteries however, present limitations and are not feasible for certain application due the high internal resistance and the bulkiness created by the need to combine them to achieve higher power capabilities. This adds to the efficiency limitation that still exists in the current photovoltaic industry. Researchers around the world have been making great progress to increase the feasibility of the solar power industry from both stand points. One of the areas that have been gaining traction is the introduction of other forms of energy storage. This paper presents a novel approach to the storage of solar energy for applications where weight may be a constraint. Particularly, we exploit the use of supercapacitors as an alternative storage method for robotics and small scale electronics. To this end, a solar powered robot was designed and tests were conducted indoor using high power light sources. Introduction The continuous discovery of novel materials used to fabricate the harvesting cells sustains the ambition of increased efficiency and the possibility of arriving to a global energy solution based on solar energy. However, solar energy is far from replacing conventional forms of energy used to supply the growing public and commercial demand. The highest market efficiency is about 24.2% and made available at a very high cost to the consumer. Incentives offered by states and the federal government encouraging residents to use alternative sources of renewable energy are having a negative effect on the solar industry by increasing demand and thus increasing the price to obtain the technology, especially in the private sector [1]. Exploring alternate sources of energy has become a priority amongst the scientific community. Recent oil spills, mine disasters, and global warming have been the driving Proceedings of The 2011 IAJC-ASEE International Conference ISBN 978-1-60643-379-9 forces behind this ever growing interest in alternative sources of energy throughout the world. Solar energy, in many ways, seems to be the obvious solution to the soon to be a global energy crisis. The conversion of solar radiation into usable energy is still very expensive and inefficient. One of the problems is the power efficiency of materials used for fabrication of photovoltaic cells (PV). Storage of the harvested energy from the sun can also present an issue, due to losses and further processing such as conversion from DC to AC. For some applications, the energy is transferred directly to a grid system. In others, batteries are used to hold the converted energy. In very small scale applications, a capacitor connected to a solar engine maintains the voltage at nearly constant level. For applications requiring higher energy and relatively light weight, this technique will not hold and the need for alternatives must be investigated. This paper presents the results of a capstone project in Electronic Engineering Technology aimed to investigate an alternative way of storing solar energy for robotics and small scale, light weight applications. First, the background information necessary to understand the technology used for the design is presented followed by a detailed design description of a solar robot used to investigate the feasibility of the project.