31 Mar 2012
Small Wind Turbines for Homes
Article by John Mahoney
Wind turbines vary from small 20watts to very large 15 megawatt units (blades of which may be taller than even the Statue of Liberty!). Of these the range 0.5 kw up to 100 kw capacity are categorized as Small Wind Turbines
Typical home applications
A typical home uses up approximately 9400 units (kwh) per annum.
If you are thinking of a wind turbine for your home electricity needs (assuming it to be a typical home) a more suitable size could be a 5 to 15 kw capacity. The vast difference in capacity is because the power generation fluctuates depending on the location and the wind velocity on the turbine.
As a rule of thumb it must be said that a Wind turbine of 3.0 kw will produce 600 kwh per month against an annual average wind velocity of 6.26 m/s, which is quit adequate for an average home application. Mind you, a small wind turbine of a capacity of 100 kw is quite a large load and the application will certainly not be a typical home.
Smaller or Micro Wind Turbines
Units having a capacity from 20 watts to 500watts are categorized as Micro or smaller turbines and are generally used for Battery Charging in recreational vehicles and sail boats or similar applications.
Cost of Energy efficiency vs. Energy production
The small wind turbine is for generating electrical Power. The cost of energy efficiency is much cheaper than the production of electrical energy. It is a good idea to work out an energy budget for your home when considering a new installation or a retrofit.
The key issue here will be to make your home more energy efficient prior to sizing the wind turbine needed. This will be more cost effective as the size of the new turbine can be reduced.
What information one must have in hand when sizing a Wind Turbine?
These data must be in your hand when selecting a wind turbine:
Estimated annual energy out put of the turbine as a function of the annual average wind speed. Maximum safe operable wind speed for the Turbine. Your Local Wind records (generally available with Wind Turbine suppliers) Your energy budget
Tips on selecting a home Wind turbine unit
Small Wind Turbines utilize horizontal axis upwind designs mostly. They incorporate two or three blade turbines which are generally made of Fiberglass The larger the diameter of the blade swept area the higher the power generated under similar conditions. The wind speed increases with the height at which the turbine is located. Higher Wind speeds generate more electricity. This also eliminates turbulence associated at lower levels. Another rule of thumb is to locate the turbine hub so that the tipoff the turbine blade is at least 10 m above the top of any obstacle within 90 m distance of the tower. Small wind turbines if fitted on steel tilting design towers it is better for maintenance and safety against high winds. Avoid using aluminium structures or towers instead of steel towers. Raising the tower height of a 10 kw turbine by 30 % may increase your capital investment by 10% but the power generation will be improved by about 25%. Do not mount Wind turbines on roof tops of houses. The noise and vibration will be unbearable within. These along with the turbulence prevailing will shorten the Turbine as well as the building structure life span Small wind turbines generally produce Direct Current (DC) as opposed to Alternating current (AC) obtained from the national power grid. Unless you want to change all your appliances to DC operation you must use a power inverter to convert the DC to AC.
Small Wind Turbines have come a long way since first developed.Today wind turbines are the fast growing energy sector investment in the world. The newer technologies available and the government sponsored grant aids make it a worthwhile investment for your new home energy installation or retrofit.
About the Author
John Mahoney is a freelance author who writes about various Renewable Energy through topics including Wind Turbines.For more info contact http://www.techstore.ie/ Renewable-Energy/Wind-Energy/ Wind-Turbines.html