Our Energy Future Comes From The Sun

Has the time really come where the world could be potentially self sustainable in terms of its energy supply and demand? Well sadly the answer to that is, not yet. However one step closer to achieving this is roof wind turbine power. Roof wind turbine models have been on the market for a number of years now but they are really coming into age as they are becoming more efficient, cheaper and easier to install.

Previous roof wind turbine models were overly bulky, not highly efficient and quite limited in their operating conditions. The period of time to pay back these models in regards to the money you would save using them was extremely long due to their cost to buy and install. Taking into consideration their maintenance costs this pushed the return period even further back. The newer roof wind turbine models can usually be installed by a good electrician and a far less costly.

Wind turbines are a booming industry. Who really wouldn't want to be independent from the Grid. It makes sense in so many ways. The roof wind turbine market only makes up a small share of this market but it is growing in leaps and bounds as people wish to take the renewable option to save money and help the planet.

In terms of the pay back period of the latest roof wind turbine devices you are looking at about 5 years compared to up to 20 years for ones you would have bought 4 years ago.

If you buy a small scale wind turbine system before December 2016 you will receive a 30 percent rebate from the government. This applies to wind turbine units with capacity under 100 kilowatts.

The latest models of wind turbines have eliminated the need for a tower to be erected to hold the devices as they now attached directly to your rooftop. This has gotten rid of two main problems. One being the need to get approval to erect a tower and the other reducing the costs dramatically as an expensive tower is not required.

The greatest advance in wind turbine technology has been the replacement of a gear and gearbox system. These systems required a wind of 7-8mph just to start the gears turning, obviously reducing efficiency. Almost a 25% reduction resulting from the initial power required as well as the loss of energy in the gear box. To replace the gear system modern engineers have used hubs and bearings and instead of a gear box magnets are used to generate electricity. New systems also boast greater wind acceptance scope as well as turbine blades which can easily be taken off and replaced in the event of damage.

During the process of researching an article about green products on photovoltaic cell systems (solar panels), I came across another way to convert the sun's light into electricity. So let's take a look at another type of solar energy system.

The Stirling engine goes back to the early 1800's, when steam was the order of the day. Steam was used to power factories, trains, and many types of work that required lots of horsepower. However, with steam came the danger of a boiler blowing up when something went wrong. Robert Stirling saw a different approach. His invention still used fire to heat the hot chamber but instead of steam, he used the heat to move pistons.

Sense its incarnation there have been many variations of the Stirling engine and many patents. The engine's simple design demands tinkering - everyone wants to add or change something to make it better. The engine has very few moving parts, requires only a single external heat source, is very efficient, and is quiet. With the new space age materials available, the problem of piston overheating is no longer a problem like it once was.

The operation of the Stirling engine is not complex, it only requires an external heat source. Some heat sources have been fuel, while some solar designs use a Fernell lens, and the latest source is large parabolic mirrors.

Operation is simple: the gases are heated by an external source, causing the hot gas to move toward a cold chamber, in the process, a piston is driven and a flywheel rotated. To put it simply, movement is achieved from heat expansion. A few knock-offs of the Stirling engines are small enough to fit in your hand. Others system are designed to drive electrical generators. They are a about the size of a fifty-gallon drum.

The system is ideal when a concentrated heat source is applied, in this case sunlight. The sunlight is collected with parabolic mirrors and focused on to the surface of the hot chamber, causing the chamber to be heated and the engine to start. This temperatures can be very high. You know this from, when as a child, you took a magnifying glass and focused it on a piece of paper. When done correctly the paper would get dark and then a flame would appear.

With better-designed engines and new types of material, a movable (tracking) parabolic mirror, and a single Stirling engine you can produce 25 kilowatts of electricity.

In a future article about green products I will list the different solar technologies and how they compare to the competition.

Michael