Vertical Axis Wind Turbines in a Highway Median SettingMatthew Browne, working with Dr. Todd Waggoner and Frank Martinez

IntroductionWith the onset of climate change upon us and the need for the reduction in fossil fuel usage, the

increased application of wind energy has become very important. Wind turbines are a clean and

reliable way to generate energy with little impact on the environment.

There are two main types of wind turbines which are categorized by their axis of rotation, horizontal

and vertical. The use of horizontal axis wind turbines (HAWTs) is much more common than the use

of vertical axis wind turbines (VAWTs) (5). This is because HAWTs typically have better efficiencies

and power outputs than VAWTs, especially at higher wind speeds and heights (6). VAWTs are

typically put into one of two subtypes, Darrieus and Savonius. Darrieus wind turbines have

efficiencies and outputs close to those of HAWTs, but they can take up a large amount of space

and can also be difficult to operate and maintain (2) . Savonius wind turbines have much lower

power output and efficiencies, but can operate better at lower wind speeds (3).

BackgroundOne of the main issues with wind turbines is that the wind needed to run them is not always consistent or

readily available (6). That is why for this research project we have looked at highway medians as a

potential for the placement of vertical axis wind turbines. Our goal is to see whether or not there is a

significant increase in wind speed and/or wind gusts in a highway median induced by the passing vehicles.

The idea of using highways to generate energy is not a new one. The basic premise has been seen and

used in a variety of ways in various places, but its use is still not widespread as the concept is still taking

shape.

MethodsOur work began in the computer lab to do research, find

materials, and find the necessary equipment to do our wind data

collection. To ensure that we would be able to collect the

necessary data with a limited budget we constructed our own

testing equipment using PVC pipe and an Ambient Weather

Home Weather Station. PVC pipe portion of the stand was

planned out and designed using the 3D modeling program

SolidWorks. We then received a permit from the District 2 Ohio

Department of Transportation to do our testing in the median of

State Route 6, South of Bowling Green, Ohio.

Data was collected in the afternoon on various dates throughout

June and July, 2011. The weather station was placed at varying

distances inside the median of the highway. Information was then

transmitted to a data logger and recorded digitally and also

sometimes by hand. Afterwards, the normal wind speed for the

area was then found using online information such as

weather.com and ODOT weather stations.

As we worked with the weather station and became accustomed

to it, the way it was used as well as the way data was collected,

changed. The first few highway research outings were left up to

the data logger to collect and manage the data. It was found then

that the data logger only recorded data every five minutes, which

was not frequent enough for our purposes. From then on data

was recorded by hand as it updated on the wireless computer

interface, which was approximately every 48 seconds. Data was

then compiled and transferred into excel for analysis.

ResultsThe table below shows the compiled data of the wind testing in on Route 6, including the direction the wind, its

speed, and frequency. The graphs below show the wind speed, gust speed, and estimated background wind

speed for three of the data collections.

*The estimated background wind speeds are based off what other weather stations measured for the surrounding area, and are

collected at a much greater height than where we collected our data. As such they are higher than what would be measured near the

ground where our data was collected.

Discussion & ConclusionBased off the data collected there is a significant increase in the speed of wind gusts in the

median of State Route 6. The wind speeds and wind gusts are consistent with what would be

operational for a Savonius Vertical Axis Wind Turbine. Having wind come from multiple

directions is also fine for a Savonius turbine as they can capture wind from any direction (2). It

can thus be concluded that a Savonius vertical axis wind turbine would operate well in the

setting of a highway median.

The city of Bowling Green, Ohio has four large horizontal axis wind turbines, yet it is not a high

wind class area (1). There are many areas throughout the United States that are not typically

suitable for the conventional horizontal axis wind turbine, but these areas may be able to

instead take advantage of vehicle induced wind on highways. Using vertical axis wind turbines

in a highway setting could be a great way to bring ( or expand) wind power to areas that may

not normally have had the opportunity for it. It is possible that the development of highway wind

power could greatly offset the need for burning fossil fuels and provide clean energy to many

areas.

The research continues as we now look to find how much energy we could expect to get out of

a VAWT in a highway setting, and how feasible this practice would be.

Turbine Model & Research ResultsIn conjunction with our wind speed testing on Route 6 we also researched wind turbines to order

discover which turbine type would be most appropriate for a highway median setting. Based off of

our research we concluded that the Savonius vertical axis wind turbine is likely the most suitable as it

performs well in low wind speeds and high gusts (5). It is also capable of being made in various

sizes and materials and can thus be designed to pose as little threat to passing vehicles as possible.

The solid, half-circle blades of the Savonius also make them easily seen and avoidable to drivers and

wildlife alike (2). Using this information and various guides on the internet, we then constructed a

model of a Savonius turbine that would be most suitable for a highway setting (4).

References(1) Blair, N., Heimiller, D., et al. “Modeling the Long-Term Market Penetration of Wind in the United States.” National Renewable Energy Laboratory. Presented at the American Wind Energy Association WindPower 2003 Conference. July 2003. (2) Carper, Christopher. “Design and Construction of Vertical Axis Wind Turbines using Dual-layer Vacuum-forming.” Massachusetts Institute of Technology. June 2010. (3) Koch-Ciobotaru, C. “Data Acquisition System for a Vertical Axis Wind Turbine Prototype.” Selected Topics in Energy, Environment, Sustainable Development and Landscaping. Ministry of Labour, Family and Social Protection, Romania. 2009.(4) Mussel, Dave. “Build Your Own Wind Turbine.” Greenlearning.ca The Ontario Trillium Foundation. <re-energy.ca> (5) “The Zeotrope: A Low-Cost, Open Source Wind Turbine.” <Applied-sciences.net> February 2011.(6) Zingman, Aron. “Optimization of a Savonius Rotor Vertical-Axis Wind Turbine for Use in Water Pumping Systems in Rural Honduras.” Massachusetts Institute of Technology. June 2007.

(Special Thanks to ODOT District 2 for the permit allowing us to collect our data).

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Wind Measurements for 7-13-11 in the median of State Route 6, South of Bowling Green, OH approx. 12ft from the Northern Road

Measured Wind Speed Estimated Background Wind Speed* Measured Wind Gust

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Wind Measurements for 7-8-11 in the median of State Route 6, South of Bowling Green, OH approx. 8ft from the Northern Road

Measured Wind Speed Estimated Background Wind Speed* Measured Wind Gust

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Wind Measurements for 7-1-11 in the center of the median of State Route 6, South of Bowling Green Ohio

Measured Wind Speed Estimated Background Wind Speed* Measured Wind Gust

Table 1 Speed (mph)

Direction 0-2 2-4 4-6 6-8 8-10 10-12 Total

N (0) 0.00% 0.00% 5.13% 0.00% 7.69% 7.69% 20.51%

NE (45) 0.00% 0.00% 0.00% 5.13% 5.13% 2.56% 12.82%

E (90) 0.00% 0.00% 0.00% 2.56% 0.00% 0.00% 2.56%

ESE (113) 0.00% 2.56% 2.56% 2.56% 2.56% 0.00% 10.26%

SE (135) 0.00% 0.00% 2.56% 2.56% 2.56% 2.56% 10.26%

SSE (158) 0.00% 0.00% 0.00% 0.00% 0.00% 2.56% 2.56%

S (180) 0.00% 0.00% 0.00% 5.13% 5.13% 0.00% 10.26%

SW (225) 2.56% 2.56% 0.00% 2.56% 2.56% 7.69% 17.95%

W (270) 0.00% 0.00% 0.00% 0.00% 5.13% 0.00% 5.13%

NW (315) 0.00% 0.00% 5.13% 0.00% 0.00% 2.56% 7.69%

Total 2.56% 5.13% 15.38% 20.51% 30.77% 25.64% 100.00%