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Archive for July, 2007

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New Record  in PV Solar Cell Efficiency

The University of Delaware and associates have achieved solar cell efficiency of almost 43% from sunlight in normal terrestrial conditions.
The current record for solar cell efficiency is 40.7% was announced only last December. The consortium will continue working to achieve an interim 50% target efficiency. They believe that much higher efficiency rates are achievable.
The highly efficient solar cells use a novel optical system that splits light into three different energy levels and focuses them onto cells of differing light sensitive materials to cover the spectrum.

An interesting feature is that the concentrator is stationary and has a wide-angle optical system that captures large amounts of light and eliminates the need for complicated tracking devices.

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Shanghai Aeolus Wind Technology
Answer Some More Questions

Further clarification of specifications etc. from Shanghai Aeolus Wind Technology Ltd. This company has been very forthcoming and communicative – top marks to them in this respect!! They would also appear to have some interesting features in their technology. I will try to follow up on their installations and get feedback if possible.

Here is the conversation:

Can you perhaps expand a little on the “pneumatic” governor system what is the technical basis??? and How safe in 80 – 90MPH gusts that we experience here at certain times of the year???

According to the aerodynamics, the pitch angel of the blades is charged automatically with the diversification of the wind speed so that the windmill rotates at the same speed to avoid the generator burn out, when the wind speed is over 43.2 MPH and become stronger.
Our turbine can still work at the wind speed of 80 – 90MPH. But when it is over 90MPH, you’ll need to stop it.

Are your VAWT OK in very wet and damp climate or in corrosive climate near the sea??

To use in such specific weather, our mechanical parts like sustaining arms and joint spots need extra surface treatment. It will cost extra.

What is the estimated useful life of these units?

20 years. Almost needs no maintenance.

Also, do you have any installations of your VAWTs in western Europe? or better still in the UK or Ireland?

We’ve just started selling for several months. There’s few customers who received our turbine in west Europe. One in Italy, they received for 2 months. One in Norway by sea, they should have received. We also delivered two by air to Germany and Switzerland around July 10th. But I don’t know where the turbine are mounted. Regards,

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An Irish man has come up with a revolutionary light weight design of Vertical Axis Wind Turbine suitable for urban domestic use. Ben Storan was the Winner of the Sustainability Design Awards 2007 at this years Royal College of Art Summer show.

The turbine is very light and flexible so it can be installed in just about any location. It uses textile aerofoils which have ribs to stiffen them. The pole is fibreglass. It weighs only 9kg, so that the total weight of an installation is 25kg roughly half that of a windmill of similar output. The inactive structure is not unlike that of a rotary clothesline, with the blades lying nearly vertically or close to the centre pole.

The height is 4m and diameter in use is approximately 2.5m. The projected selling price including generator is just under £1000. Power output is estimated to be 1.2 kW at 12m/s. The average wind speed in Ireland is about 5.5m/s more or less depending on the geography.

The flexible design would make the windmill safe in severe weather by simply bending in the wind.

Good luck with the development stage Ben.

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Interesting Wind Turbines

from

Shanghai Aeolus Wind Technology



I had a very prompt and comprehensive reply from one Chinese Wind Generator manufacturer Shanghai Aeolus Wind Technology Co. Ltd. who make a line of vertical axis wind turbines. And yes, the Chinese can offer wind generators at substantially lower prices. See the price list below. I publish also two photos, which they sent me, which clearly show the design of the rotor blades

Here is their reply to my query;

Thank you for your email.
Our products line now extends from 200watts, 300w, 500w, 1000w, 3kw to 10kw.

Our 3kw and 10kw products “pneumatically” control the rotating speed of the wind mill when wind speed is over the rated speed. Therefore our products can be used where the wind is very strong, they could still work stably and continuously. This technique is unique and is one of our patents. All of our products are patented and owned by us.

Compare the VAWT (vertical axis wind turbine) with HAWT (horizontal axis wind turbine). VAWT has no noise and is safer. They have different structure, different use, different market. We have the most advanced VAWT technology in this field.

Our turbine can be used in both rural and urban areas given that the local wind and site conditions fit. In public lighting, monitor controlling system, oil fields and other city facilities and commercial purposes could our products be used as well. Because wind directions don’t affect the function of the equipment, it works even better on yachts, islands, offshore oil fields where wind is more turbulent.

Attached the specification of each model and price list(FOB Shanghai) for your reference. Our minimum order quantity is 1 set. Delivery times is 30-45 days.

Let me know if you have any other question.

Regards,


The Shanghai Aeolus Wind Technology Co. Ltd. site link is as follows: http://www.sawt.com.cn/index_en.asp

Here is a very interesting piece of information – the price list!! Prices are in US Dollars and are less shipping costs.

Price(USD) Fob Shanghai
Model -Power — mill system – controller = inverter (off grid)
P200 – -200W US$1080
P300 – 300W US$1230
P500A – 500W US$1730
P500B 500W US$1630
P1000 1000W US$2580
P3000 3000W US$6480
PK10 10KW US$19000

Note: This price is for goods. The sample price is 1.05 time of goods. And we have no MQO.

A 3Kwatt turbine and gear for US$6500 that’s approx €4715 plus shipping and tax. You must also add in the cost of a mast and installation. These prices look to be very reasonable.

If any reader has experience of these turbines I would really appreciate hearing from you.

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Chinese Wind Generators

I came across a lot of Chinese windmills while digging for information. But this one is especially interesting as it uses the vertical axis design.

I am waiting to hear from the company regarding prices etc. Hopefully they will offer low cost products and it will be interesting to see how these pan out for reliability etc. when tested in the west. I just hope the Chinese are not to coy with communications and information!!!

Here is the technical specs. for their 3Kw model: Model P-3000-G
Mill diameter: 300 cm Blade length: 360 cm
Start up wind speed: 2 m/s Working wind speed: 4-25 m/s
Rating wind speed: 12 m/s Safe wind speed: 50 m/s
Rating power: 3000 w Rating out put: DC 200~450 V
Governed speed style: Aerodynamics Brake style: Mechanism
Pillar high: 5.5 m Net weight: 500 Kg (No Pillar)

I have copied some of the company’s blurb on their product along with some very poor quality photos. Here is the site link:

http://www.sawt.com.cn/service_en.html

(Sorry for the terrible quality of the photos but this company use absolutly tiny jpegs and not great photos to begin with)
The company blurb:

We are an innovative company engaged in vertical axis wind turbine generator technology. We entered Shanghai China in 2005. Our research focuses on vertical axis wind turbine generator including systematic study on aerodynamics, materials, structures and generators.

We have made breakthroughs in commercializing of vertical axis wind generator, the worldwide Sphinx’s riddle. We have completed product designs for 200-watt, 300-watt, 500-watt, 1000-watt, 3000-watt,10kw and ready for marketing and sales. 200-watt and 300-watt products have successfully gone through experiments many times in wind tunnel.

One 300-watt product has been installed in the national highway monitoring system in northern part of China. With more financing, we will begin manufacturing samples of megawatt products and conduct on site tests. We have obtained 8 international invention patents which is the threshold to enter the vertical axis wind turbine section. Our products are going to completely replace the products of traditional horizontal axis wind turbine generator in the near future.

Q: What is Vertical Axis Wind Turbine compared with traditional horizontal axis wind turbine?
A: If the pivot of the turbine is vertical to the ground, then it is a vertical axis wind turbine, and visaversa. Most of the wind turbines, the ones with three blades that we see frequently today are horizontal axis wind turbines.

Q: Why vertical axis wind turbines make much less noise than horizontal axis wind turbines?
A: The cause of noise is mainly because of blades cutting through air flow. However, air flow through vertical axis wind turbine is different and the rotation speed is much lower. As a result, it produces much less noise, almost no noise at all.

Q: Why are our products most advanced?
A: The design and development of the products followed a strict process. Firstly, we verified our ideas by relevant theories, and then conducted computer facilitated simulation (CFD). When choosing materials, we calculated, compared and adjusted intensity of various types ofmaterials. Before finalizing the design, each new product has to go through countlessexperiments in wind tunnel to further prove its functions. We already have 9 international
invention patents resulted from the research. So Aeolus is the leader in the vertical axis windturbine section of the industry with cutting edge products and it is the only one who hassuccessfully transferred the technology to manufacturing.

Q: Who are the potential users of vertical axis wind turbine?
A: As it has advantages such as lower noise, it can be used in both rural and urban areas given the local wind and site conditions fit. Public lighting, monitor controlling system, oil fields and other city facilities and commercial purposes could use our products as well. Because wind directions don’t affect the function of the equipment, so it works even better on yachts, islands, offshore oil fields where wind is more turbulent.

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Here is another take on the vertical axis windmill by a dutch company called Turby. Their offering is a 2.5Kw generator which comes with a price tag of €11,466 for the turbine and converter. The mast and installation are extra.

I am struck by the high price of these wind turbines. I wonder what makes them so expensive? You could buy a car for the price. Hopefully the Chinese will start to produce wind turbines and once they get their hand into this type of kit they will turn it out for a third of the money.

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Some Development of the Vertical Axis Windmill

Cleanfield in Canada have developed a variation of the vertical axis windmill which can generate up to 3.5Kw/h. Aptly called the V (for vertical I presume) V3.5, it’s three-metres tall and 2.75 meters in diameter. It stands on a stubby pylon for flat rooftop mounting.

The turbine blades typically turn at 120 rpm, but can go to 180 rpm (three revolutions per second) or higher in high wind. It has very low wind drag, operates at very low wind speeds, and makes very little noise compared to other windmills so they say. It is therefore very suitable for mounting on top of flat roofed buildings. It can be also mounted on a mast or pole.

I have made several attempts to get more information from Cleanfield. They are coy to say the least; maybe they don’t trust me, as I am known to be somewhat outspoken and critical.

I did manage to learn that the complete package for the 3.5Kw/h unit, which includes mountings, inverter and control gear, sells in Canada for C$14,000. That’s about €9770. It is therefore not a cheap unit by any stretch of the imagination. It would also require a fair bit of open space for urban use, the lady at Cleanfield I spoke to said a 1 acre site would be preferrable. It would therefore not be suitable for inner city or congested areas, other than for rooftop mounting.

It looks like a promising development of the vertical axis design of windmill but a bit pricey I’d say.

No doubt the Chinese will already be copying the unit and they will be able to sell it to us at half the price.

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