Let's Build an Optimization Tool for DIY Wind Power Airfoils

While I absolutely love the DIY accessibility of home wind power generation projects like the Chispito Wind Power Generator, The DIY aviation nut in me is screaming that we could all get significantly more power out of rigs like this if we had an optimization tool that would ask us our motor specs and what the wind is like where we're mounting our generators, then spit out .stl files of the right shape airfoils to get the most power out of the wind. I don't know what percent difference the average builder could expect to see from optimized blades...but based on the research paper linked at the very bottom of this post, I think it would have to be huge. The difference between an aircraft-optimized airfoil and a wind turbine optimized airfoil can be as much as 50% in normal wind conditions, and neither of those airfoils seem to have much in common with the simple   blades we DIY types make out of cut up PVC pipe.

CNC hot wire foam cutting technology is a good start for rapid prototyping custom airfoils based on .stl files. With this technology in play, I could see the production of custom wind generator blades becomming a great little microfactory business.

The past couple times I started to post something along the lines of "Dear Santa or Jesus or open source community members, next I would pretty please like the following open source tool to exist" I found what I wanted in a Google search. The most recent two examples were free, open source computational fluid dynamics code and an inexpensive, open source stereolithography machine.

This time, the closest I have found to an airfoil optimization tool for DIY wind power generation are these research papers:

• Aerodynamic Shape Optimization of Vertical Axis Wind Turbine Using Differential Evolution: Summarizes the preliminary results of a UT Arlington Aerospace Engineering group's efforts to create an automated airfoil optimization code. Bonus: if you want to learn the basics of wind power theory, read the introduction to this paper. It'll be a great vocab lesson even if math isn't your thing. The group published this paper under the creative commons attribution license...cross your fingers that they will be just as generous with the source code they're working so hard to create.
• Study of the Performance and Robustness of NREL and NACA Blade for Wind Turbine Applications: This study predicts that major power gains (~10-50% over the wind speed range of 3-9mph) would result from building small home-use wind turbines using the airfoils designed for horizontal axis wind turbines by the National Renewable Energy Lab (NREL) as opposed to the currently common practice of using airfoils NASA designed for aircraft back when the agency was still called NACA. As you can see in table 1 and in figure 3 (click here, scroll down), the NREL and NACA airfoils look almost identical. I suspect that using either type would yield a vast improvement over the current DIY standard of cut up PVC pipe.

The top one looks like a great start...but I'd like to see the open source community run with it and start making better wind turbines.

Plans for a Simple DIY Wind Generator

The Chispito Wind Generator is a small, DIY wind power generator capable of generating 100 Watts in a 30 mph wind. It starts charging a 12-Volt battery in a 7-10 mph wind, and you can build one with the relatively short list of inexpensive parts and tools found here. The Chispito Wind Generator uses an old treadmill motor for the generator.

If your electricity use is average (around 11,500 kWh/year for US households) and you lived somewhere with 30 mph winds 24-7, this thing could provide about 7.5% of your power needs.  Nobody I know lives anywhere that is consistently that windy, but the Chispito Wind Generator could be a fun and educational DIY project in a lot of places. Here is an 80-meter wind resource map of the US that may give you some idea of the wind speeds in your area, although 80 meters is a bit high for a back yard wind generator.

For pictures and build instructions, check out "How to Build a Chispito Wind Generator" page.

You make the blades on this baby using some cut up PVC pipe and sand paper. I love that the tools and materials needed to build these blades are so close to universally accessible. If you follow this blog, bets are probably good that you could finish a significant percentage of this wind power generator project before making a trip to the hardware store.

All that said, the  DIY aviation nut in me is screaming that we need an inexpensive, open-source way to optimize airfoils for domestic-use, DIY wind power generators. Look out for a future post on the huge increases in power generation that can be obtained by using well-optimized airfoils, and my ideas about how we can make such airfoils inexpensive and widely available.

Green Power Science LLC offers Free DIY Solar Power instructions on Youtube

The folks at GreenPowerScience have provided a free collection of great DIY solar power tutorials.

You may need engineering chops to want to do this sort of thing, but the GreenPowerScience team seems to break things down in a way that makes an engineering or technology background optional. Here's the example that got me inspired to create my own residential solar power system:




I am not sold on the idea that solar power can be cost-effective. In the 2nd quarter of 2011, the average cost of residential solar power systems was $6.42 per Watt. I've heard of DIY solar power gurus claiming to achieve $1 per Watt...but I have also read that solar cells alone cost $2.50/Watt, and that the cost of other components adds up fast. When/if I build my own system inspired by the GreenPowerScience team, I hope to document my costs and time investment for a future post. My swag on financial break-even is as follows:

Divide the initial cost per Watt at installation by 1W x hours/day of sun x (1kW/1000W) x days of sunshine/year x 0.7 to account for reduced generation when sunshine is less direct x $/kWh.  According to my math, the $6.42 per Watt system would take 46 years to pay for itself at 15 cents/kWh. Using the map of average daily solar radiation from nationalatlas.gov could help tighten these numbers a bit.

Here's an informative post from Michael Bluejay on the cost of electricity, and here is another where he makes the case that (subsidized) solar is affordable. Data from the US Energy Information Administration, show that the average cost per kilowatt hour in the USA is 11.5 cents, with a low of 7.99 cents in Idaho and a high of 28.10 cents in Hawaii.

It could be an educational, exciting, and productive form of charity/volunteer work to build and install residential photovoltaic power systems for families who are having difficulty making ends meet, instead of making one-time monetary donations. That sort of project could fit well with Christmas in April initiatives like this one, or Habitat for Humanity.

About the Open Source Tech Revolution

Purpose

The purpose of the Open Source Tech Revolution is to make freedom and autonomy more accessible to those who want it.

The purpose of the Open Source Tech Revolution Blog is to help get the OSTR rolling!

Lots of us have great ideas for new technology and new products that have a lot of potential to improve lives or make money.  Often, we lack the time, expertise, or skill set to make many of these ideas a reality.  I am a proponent of the idea that just about anyone can learn just about anything, given some time and access to the right information.  Thanks to brick and mortar libraries and great sites like Wikipedia and YouTube, we have a lot freer access to a lot more information than ever before.  Simply having the time to learn what we need to know in order to proceed, and in many cases having the money for the proper tools, equipment and raw materials are still major road blocks to achieving the innovations we envision.  Through networking, and collaborative design efforts, we can bypass those road blocks to an unprecedented extent.

Why would People give good ideas away for free?

We want awesome stuff to exist.  Sometimes people have awesome ideas that they have neither the time nor the expertise to bring to fruition alone. One way to increase your chances of actually using something awesome that you dream up but don't plan to create is to make the idea public and let others attempt to create it.

Philanthropy: Giving away empowering knowledge and technology is a way to give people who need it a chance to improve their quality of life.

Lots of us have ideas we're not using anyway: Given the choice between sharing our good ideas, holding onto them in hopes of future for-profit development, or waiting for others to independently come up with and act on the same idea, some people may benefit most from sharing.

Why would anyone want to work on open-source design projects for free?

• Doing things that really matter makes people happy.
• Being productive makes people happy.
• Taking on challenges makes people happy.
• If you want something to exist, and it doesn't exist yet, you can fix your problem by helping to create it.
• By collaborating on ground-breaking engineering projects, you will probably get to know fascinating people with whom you share exciting interests.
• If you want to learn some useful skills, collaborating on a project where those skills are needed is likely to provide you with added motivation, priceless practice with your new skills, and a network of mentors who already possess the skills you are looking to acquire.
• If you are looking for a career in engineering, science or technology, gaining the experience of collaborating on successful, useful and innovative designs will show prospective employers that you have what it takes.
• If your skills and creativity are underutilized in your current career, collaborating with cutting edge projects as a hobbyist could be a thrilling opportunity to be yourself.
• If you think you might have engineering chops but you are not certain, collaborating on an engineering project would be a useful way to test the waters.

How is posting a bunch of ideas on the internet going to help anyone in any way?


It's probably not going to.  I am researching the efforts of others to crowd-source the development of technical projects and working to develop a web-based collaborative design application that solves as many as possible of the logistical problems with collaborating from a distance.