Development


VERTICAL AXIS WIND TURBINE

History:

Although the first practical applications of the use of wind energy were done centuries ago for milling grain and pumping water, only in the last decades wind has been used to effectively generate electrical energy.
The development basically was done on horizontal axis turbines. To better use high wind intensities and increase the area over which wind is captured, the height of towers and diameter of blades have grown and significantly increased the capacity of these turbines which presently are focused on the generation of high power, in the MW range.
The vertical axis turbines, of which best known are the Savonius and the Daerrius models practically showed no evolution in this period, in spite of having the advantage to capture the wind coming from any direction and operate with lower wind intensities.
With the availability of new materials and new technologies we decided to invest in the development of vertical axis wind turbines improving its output so as to be able to generate energy in low and medium powers(KW) already with lower wind intensities and allowing its use by isolated communities which do not dispose of electrical energy or have to use liquid fuel generators, which are expensive to run as well as noisy and pollute the atmosphere.

Concept:

We started the development based on the Savonius concept and incorporated the use of flexible sail materials resulting in energy capturing surfaces which automatically adjust to the relative direction they are at in any moment – using the concept of sailboats which go with wind from behind, across and against the wind- in such a way that the wind energy is better used.
We have a published patent registration request under the title “Sail driven wind turbine”

Development:

We built a model which initially had three sails to test the concept. When we went over to six sails it showed itself promising.
The project of a prototype was then developed with various simulations in the Solid Works Flow Simulator.
Together with SENAI- Mariano Ferraz School/ Vila Leopoldina –SP a 1:14 scale model of the prototype was built and tested in the wind tunel of the Technological Reserch Institute-IPT /SP to verify the results we had obtained in the simulations.

Modelo no tunel de vento do IPT

IPT wind tunel

In the essays, various angles of attack and sail widths were tested looking for the best performance and nominal capacity for winds in the 6 to 12 m/s range.
We managed to get a power coefficient (Cp) of over 0,5 for winds of 6 m/s
Once the results were confirmed we built the prototype, also in partnership of the Senai school.
For the development of the flexible materials and its methods of securing to the structure we obtained a grant from the Fundação de Amparo à Pesquisa do Estado de São Paulo- FAPESP trough a small enterprises incentive program which also allowed us to give two scholarships one to a textile specialist and the other to a controls and automation student.
Tests of the mechanical mechanism were started in September 2011 and various adjustments were made to the project.
Wind measurements in Limeira-SP, the location of the prototype, have been taken since August 2010.

Gerador Eólico Vertical a Vela

GEVEV – Vertical axis wind turbine

Present Status:

For the performance tests we built a smaller model in the form of a water pump for the practical measurement of the productivity with varying winds.
This will also be used to confirm the usefulness of the concept of pumping water in areas where electrical energy is not available or scarce as is the case in large areas of Brazil with particular interest for cattle raising farms in distant areas and in the northeastern backcountry. This prototype was built with a 3 inch piston pump to get water from 20 m depth at a rate of 600 l/h with 3 m/s wind and getting to 2000l/h at 10 m/s.
FIESP – federation of São Paulo State Manufacturing Industry, through its SENAI-SP approved support to the project with the Mariano Ferraz school and we will be building an operational prototype during 2012 with the objective to generate 1 to 10 KW with winds of 4 to 9 m/s ( equivalent to 30 KW in market numbers for wind generators, as in general winds of 12 m/s are used, very rate intensities in most of the world, except in areas where the large wind power units are established)

BEVEV - Bomba d'água eólica

BEVEV – Wind Water Pump