NO TECH MAGAZINE

Klopotec: a Bird-Scaring Wind-Rattle

kris de decker — Tue, 23 Oct 2018 00:50:01 +0000

A “klopotec” or “klapotets” is a wooden mechanical device on a high wooden pole, similar to a windmill. It is used as a bird scarer in the vineyards of traditional wine-growing landscapes of Slovenia, Austria, and Croatia. The first written mentions of the technology date to the second half of the 18th century, whereas its oldest depictions date to the first half of the 19th century.

As the axis rotates in the wind, wooden hammers are lifted off their resting position by fixed notches. As they fall back, they rhythmically impact on a wooden board. While the quality of the sound is dependent on the wood of which the hammers and sounding boards are made of, the rattle frequency depends on the number of hammers, as well as changes in wind speed.

The klopotec was only used from July until November, after which it was disassembled for winter. The largest construction of this type in a natural setting stood in the Sausal mountain range, near the summit of the Demmerkogel. It was 16 meters high, and each of the eight hammers weighed 40 kilograms. It was destroyed in a storm in November 2017.

Sources: 1 / 2 / 3.

Windmill on Ice or Water Bearings Has Low Friction at Low Cost

kris de decker — Thu, 26 Apr 2018 20:45:21 +0000

Simon Gripenberg, an artist from Finland, developed new types of vertical windmills, inspired by ancient Persian windmills and built from recycled materials. Most interestingly, the windmills float in water or spin on ice, so that Gripenberg manages to obtain low friction at low cost.

The vertical windmill on ice uses a number of skis to benefit from the low friction of the ice. The windmill spins around an axis that is fixed into the ice. The small prototype works very good, but if scaled up in size it would be necessary to take lifting forces into account. [Video]

A similar concept is applied to a vertical windmill floating on water, contained within a rigid structure. The windmill rotates smoothly with the use of a simple water bearing. [Video]

Gripenberg also made a wind-powered carousel from a 6 ton ice sheet. [Video]

Images: Simon Gripenberg

Wind Power System Made from Plastic Buckets

kris de decker — Sat, 23 Jul 2016 19:50:25 +0000

A wind power system made from plastic buckets is seen on boats at a floating village in Hanoi, Vietnam June 29, 2016. REUTERS/Kham

“Vietnamese families living in slums along the Red River in Hanoi are using red plastic buckets and old printers to help light homes, cook meals and slash electricity costs by as much as a third.

The recycled goods form the blades and motors of electrical generators that power old motorcycle batteries to illuminate lamps with a brightness equivalent to a 45-Watt light bulb.

Though the output generated is small, it makes a significant difference for families previously denied power because they lived too far from a power station or had to ration supply because of the expense.”

More pictures and information at Reuters: Plastic buckets, broken printers shine light on Hanoi’s poor. Via Playground Magazine.

See all our low-tech windmill posts.

Different Types of Windmill Sails

kris de decker — Sat, 01 Nov 2014 11:24:26 +0000

François Porcher has translated our 2009 article “Wind Powered Factories: History (and Future) of Industrial Windmills” (“Des fabriques mues par le vent: histoire (et avenir) des moulins à vent“) and sends us the image above to complement the illustrations. For a high-resolution image, go here. More articles have been translated to French and other languages.

Previously:

Self-Trimming Wingsails

kris de decker — Fri, 01 Feb 2013 21:54:54 +0000

“Since the invention of aircraft, a similarity has been noticed between the operation of sails on boats and the function of wings of aircraft. Sails on boats provide thrust in a horizontal direction derived from moving air, and wings on aircraft provide ‘lift’ in a vertical direction to support a plane in the air, also from moving air (relative to the plane). In order to fly, wings had to have a certain degree of efficiency, and some experimenters have realised now that aircraft-type wings could be used on a boat and would be more efficient than sails.”

“Having tested wings on boats in place of sails (‘wingsails’) designers noticed another feature used on aircraft that would be useful to use in conjunction with wingsails – controlling the wingsail with another smaller surface mounted behind or in front of it (a ‘tail’). There are many examples of tails used to control the direction of bodies both in the water and in the air, and aircraft use them to adjust, to a precise degree, the lift or (angle of attack) of their wings.”

“If a tail is used attached to a boats’ wingsail, it can adjust the wing perfectly to every small change of wing direction, in this way relieving the sailor of this task, which is mostly guesswork and at best very approximate, and it can perform that job much better than any sailor can do. Such a wingsail/tail combination is referred to as a self-trimming wingsail.”

The Fastest Sailboat in the World

kris de decker — Thu, 13 Dec 2012 17:55:40 +0000

The Sailrocket, a sailing boat that we have talked about before, is the fastest craft under sail, after breaking the 2010 record held by a kiteboarder.

During the last run in Namibia in November 2012, an improved version of this unconventional boat reached an average speed of 65.45 knots (121.21 km/h or 75.31 mph) over a distance of 500 meters. Earlier this year it set speed records of 59.23 and 59.37 knots.

Record sailing speeds have almost tripled since the beginning of the 1970s. Those who think that sailboats are a technology from the past, think again.

See and read more at YachtPals and Sailrocket.

Making Bellows

kris de decker — Wed, 31 Oct 2012 21:24:56 +0000

“This is hopefully the start of a set of documents that will help in the construction of a portable, authentic forge and bronze casting set up. I am starting with the bellows as I can use them at home to help get the fire going in the winter months.”

“I have repaired a number of sets of bellows, but this is the first set I have actually made myself from scratch. They appear to work well – good flow rate, nice range of movement, practically no air loss. If you follow any of the instructions below and it doesn’t work properly – well then you are just doing it wrong.”

Making bellows.

Building Plans for Dutch Industrial Windmills (1850)

kris de decker — Mon, 08 Oct 2012 14:25:11 +0000

This collection of 21 building plans for 5 different types of Dutch industrial windmills was published in 1850. There is a saw mill, an oats mill, a flour mill, and two pumping mills. The book contains no text, only illustrations.

“Theoretisch en practisch molenboek: voor ingenieurs, aannemers, molenaars en andere bouwkundigen“, G. Krook, 1850.

(“Theoretical and practical windmill book; for engineers, contractors and millwrights”).

Follow the link above for high-resolution images.

More:

Sailing 10,000 Nautical Miles Using the Stars, Moon and Sun

kris de decker — Sun, 29 Jul 2012 17:01:10 +0000

A group of intrepid Māori sailors from New Zealand will take on the world’s biggest ocean, the Pacific, in an attempt to sail to Easter Island, the most remote inhabited place on Earth, without GPS, charts, maps, or even a compass.

Instead the group will be guided by the traditional techniques that helped the Polynesian people traverse the wide expanses of the Pacific and settle the islands of Hawaii, New Zealand and Tonga, to name just a few – techniques like the movement of the stars, the sun and moon, oceanic currents and bird and animal life.

The sailing odyssey is part of an effort by Polynesian academic and cultural groups to reclaim the navigational knowledge of their forebears, much of which was lost after European colonization.” Read more (official website). Previously: Polynesian stick charts / Satellite navigation in the 18th century / Developed nations dangerously over-reliant on GPS.

Trees as Indicators of Prevailing Wind Direction

kris de decker — Fri, 09 Sep 2011 02:33:57 +0000

“In mountainous areas, winds are often complex and the available wind data are limited and provide little information on wind direction. One technique for determining the mean wind direction is tree flagging. Trees have been used for hundreds of years as an ecological indicator of wind direction, wind exposure and as a measure of the severity of wind and ice damage. This handbook will describe techniques for ‘reading’ the information written on the trees by wind.”

“Flagged trees only reflect the prevailing wind direction of the strongest winds, which may occur during only part of the year. Seasonal variations in the wind have a pronounced effect on the type of wind deformation and these effects are characterized in this handbook. Techniques for estimating the mean annual wind speed have been developed using indices of wind effects on trees. These indices have been calibrated on two widely distributed species of conifers. The main conclusions are that trees provide a simple, inexpensive and quick method for identifying promising locations where more detailed measurements can verify the wind potential.”

Trees as an indicator of wind power potential (.pdf), John E. Wade & E. Wendell Hewson, 1979.
Vegetation as an indicator of high wind velocity (.pdf), DOE report, John E. Wade & R.W. Baker, 1977

More low-tech wind power.

The Junk Blue Book: Indigenous Fishing and Cargo Craft

kris de decker — Fri, 29 Jul 2011 00:31:56 +0000

“The Junk Blue Book of 1962 is a detailed catalog of the indigenous boats of what was then South Vietnam, during a period when most such vessels were still powered by sail. It was a manual put together by the US Dept. of Defense early in the involvement in the war in Vietnam. It was used as a guide to identify coastwise marine traffic involved in smuggling supplies and personnel south into the Republic of Vietnam from then North Vietnam. Although its production was driven by perceived military necessity it is a unique chronicle of the indigenous fishing and cargo craft of the mid and southern Vietnamese coasts.”

The book is in the public domain and can be found on scribd. A pdf-version is available on a dedicated site. Via Indigenous boats. See also: the wooden work boats of Indochina.

Wind Farms Can Be Made 10 Times Smaller

kris de decker — Thu, 14 Jul 2011 03:10:28 +0000

“Modern wind farms comprised of horizontal-axis wind turbines (HAWTs) require significant land resources to separate each wind turbine from the adjacent turbine wakes. This aerodynamic constraint limits the amount of power that can be extracted from a given wind farm footprint. The resulting inefficiency of HAWT farms is currently compensated by using taller wind turbines to access greater wind resources at high altitudes, but this solution comes at the expense of higher engineering costs and greater visual, acoustic, radar and environmental impacts.”

“We investigated the use of counter-rotating vertical-axis wind turbines (VAWTs) in order to achieve higher power output per unit land area than existing wind farms consisting of HAWTs. Full-scale field tests of 10-m tall VAWTs in various counter-rotating configurations were conducted under natural wind conditions during summer 2010. Whereas modern wind farms consisting of HAWTs produce 2 to 3 watts of power per square meter of land area, these field tests indicate that power densities an order of magnitude greater [21 to 47 watts] can potentially be achieved by arranging VAWTs in layouts that enable them to extract energy from adjacent wakes and from above the wind farm.”

“The results suggest an alternative approach to wind farming that has the potential to concurrently reduce the cost, size, and environmental impacts of wind farms.”

Read more: ‘Potential order-of-magnitude enhancement of wind farm power density via counterrotating vertical-axis wind turbine arrays’, John O. Dabiri. Introduction. Research paper (pdf). Via Ecogeek.

The Homemade Windmills of Nebraska

kris de decker — Thu, 12 May 2011 15:42:50 +0000

“The merit of homemade mills has enjoyed such prompt recognition that they are going up daily. Not to the detriment, we are happy to say, of those important adjuncts to the farm, the shopmade mills, but in addition to them.

In a given community, the man who puts up the first mill generally furnishes the model for the rest of the community. Hence it seems the more desirable that good models should be at hand, the better models are often of quite as easy constructed and no more expensive than the poorer, and their efficiency considerably greater.

It is advantageous to have good models to copy, and the next best thing to the actual model is a good simple drawing. This is the first object of this paper on our homemade windmills; it aims to supply cuts illustrating all sorts of windmills, as found in this State.”

“The homemade windmills of Nebraska” (pdf), Erwin Hinckley Barbour, 1899. Illustration: a wind powered sawing machine.

Can Renewables Power Consumer Societies? The Negative Case

kris de decker — Wed, 11 May 2011 01:03:47 +0000

“Virtually all current discussion of climate change and energy problems proceeds on the assumption that technical solutions are possible within basically affluent-consumer societies. There is however a substantial case that this assumption is mistaken. This case derives from a consideration of the scale of the tasks and of the limits of non-carbon energy sources, focusing especially on the need for redundant capacity in winter. The first line of argument is to do with the extremely high capital cost of the supply system that would be required, and the second is to do with the problems set by the intermittency of renewable sources. It is concluded that the general climate change and energy problem cannot be solved without large scale reductions in rates of economic production and consumption, and therefore without transition to fundamentally different social structures and systems.”

Read more: “Can renewables solve the greenhouse problem? The negative case” (pdf), Ted Trainer, Energy Policy, March 2010. Also check out the author’s website, where you can find similar papers, like this one.

How to Rig a Windmill Sail

kris de decker — Mon, 10 Jan 2011 23:12:12 +0000

Source: “Travailler au moulin / Werken met molens”, Jean Bruggeman, 1996.

Tree Windmill (1901)

kris de decker — Mon, 06 Dec 2010 20:54:16 +0000

Last year, William Kamkwamba made headlines around the world with his crude windmills built out of tree trunks and scavenged materials.

He could have saved himself some work if he had seen the illustration on the right, which I copied from a 1901 Dutch newspaper. The accompanying text says:

“Windmills are ugly contraptions and many attempts have been made to make them look better. This illustration shows how nature and mechanics can coexist.”

“It is a windmill constructed in combination with two trees. The trees only serve as a support for the upper part and for the ladder to reach the top. The mill was built in Illinois (US) and worked so well that several have been constructed.”

I could not find any more information about it.

Small wind turbines put to the test (2)

kris de decker — Wed, 15 Sep 2010 23:26:09 +0000

The Oil Drum runs an extended and rewritten version of our 2009 article on small wind turbines – including additional tests results from the UK.

“Two real-world tests performed in the Netherlands and in the UK confirm our earlier analysis that small wind turbines are a fundamentally flawed technology. Their financial payback time is much longer than their life expectancy, and in urban areas, some poorly placed wind turbines will not even deliver as much energy as needed to operate them (let alone energy needed to produce them). Given their long payback period relative to their life expectancy, most small wind turbines are net energy consumers rather than net energy producers.”

Wind Powered Trikes

kris de decker — Mon, 19 Jul 2010 00:00:07 +0000

Pterosail Trike Systems is sailing and cycling over 3,000 miles from coast to coast across the USA this summer. The Pterosail is a street-legal recumbent tricycle with sails. It can reach up to 40 mph in good winds. No wind? Pedal. See also, below: the Whike, a Dutch made sail assisted trike.

Sailing Directly into the Wind

kris de decker — Tue, 12 Jan 2010 12:31:22 +0000

“In the late 90s/early 2000s my interest was in developing boats that can sail directly into the wind. To some, this seems impossible, and they find it hard to accept that it is possible to overcome the wind using the force of the wind itself. This technology has further implications also, it can allow a boat, or a buoy, to remain stationary in the water, unsecured, no matter how hard the wind blows without using any fuel. Having revived the project recently (2008) I am doing further research.”

I cannot help but admire the simplicity of the design. Find all information here.

Windmills and Wind Motors – How to Build and Run Them (1910)

kris de decker — Tue, 15 Dec 2009 01:11:53 +0000

“I have endeavoured in the following pages not only to interest the practical amateur in a branch of mechanics unfortunately much neglected, but also to present a series of practical original designs that should prove useful to every reader from the youngest to the most advanced.”

Chapter 1 : windmill evolution
Chapter 2 : a small working model windmill
Chapter 3 : a small American type windmill
Chapter 4 : a small working windmill
Chapter 5 : a practical working windmill
Chapter 6 : production of electricity by wind power

Windmills and wind motors – how to build and run them (1910).