Introduction

We started this project from the idea of connecting two environmental issues: solid waste (especially the plastic bottles that are everywhere) and the need of sustainable use of energy. The fossil fuels are non-renewable resources, therefore we are suppose to find another way of proving our energy supplies. Wind energy is non polluting, save, renewable. The plastic waste are very difficult to collect, treat/reuse. Most of the plastic bottles end up in garbage dumps without any possibility of recycling its. We suggest a methods that allows us to solve both environmental issues - waste and energy, by using plastic bottles for manufacturing a small and affordable wind plant, a Savonius turbine.

The sun has a lot to do with creating winds. Winds above continents and oceans occur because of temperature differences around the world. Some places, especially those near the Equator, receive far more direct sunlight than those closer to the Earth’s north and south poles. As a result, the air over these areas warms up and then rises. Cooler air from the surrounding area rushes in to fill the space left by the rising air, creating a surface wind.

Air is constantly on the move. In some places, especially along coastlines and in mountains, it provides a highly reliable source of mechanical energy. Humans have invented an amazing array of devices that can harness the energy of the wind and put it to practical use.

One of the oldest uses of wind energy is transportation. The first primitive sails were probably made from woven mats held aloft by wooden poles or human hands. Modern sailboats have very efficient sails and masts constructed from strong, lightweight materials such as Kevlar (the material used in bulletproof vests) and titanium. They work like aircraft wings to generate forces that pull the boat in the desired direction.

Long before the invention of electricity, early wind turbines did very useful work. Windmills were used in many places in Europe over the last several centuries to turn heavy granite disks called millstones. The millstones were used to crush dry grains such as wheat, barley, and corn to make fl our or meal.

The Netherlands is famous for its windmills. In truth, most of these structures are not mills at all, but water pumps. The Dutch created new farmland along the coast by building dikes around low-lying estuaries and mudflats and pumping out all the seawater. The “windmills” provided a steady supply of mechanical energy to lift seawater into the canals, allowing the new farmland to dry out.

Savonius turbines are one of the simplest turbines. Aerodynamically, they are drag-type devices, consisting of two or three scoops. Looking down on the rotor from above, a two-scoop machine would look like an "S" shape in cross section. Because of the curvature, the scoops experience less drag when moving against the wind than when moving with the wind. The differential drag causes the Savonius turbine to spin. Because they are drag-type devices, Savonius turbines extract much less of the wind's power than other similarly-sized lift-type turbines. Much of the swept area of a Savonius rotor is near the ground, making the overall energy extraction less effective due to lower wind speed at lower heights.

Savonius turbines are used whenever cost or reliability is much more important than efficiency. For example, most anemometers are Savonius turbines, because efficiency is completely irrelevant for that application. Much larger Savonius turbines have been used to generate electric power on deep-water buoys, which need small amounts of power and get very little maintenance. Design is simplified because, unlike horizontal-axis turbines, no pointing mechanism is required to allow for shifting wind direction and the turbine is self-starting. Savonius and other vertical-axis machines are not usually connected to electric power grids. They can sometimes have long helical coops, to give smooth torque.

background information

Watch a video with our Savonius turbine!