How to make a thermal solar powered Stirling engine - Part 1

This is a fun little alternative energy project that combines two of my favorite highly-efficient devices into one awesome sustainable unit! The thermal solar panel/solar oven provides the heat needed to create the temperature variance in the Stirling engine.

This project is really intended to demonstrate the functionality and simplicity of thermal solar energy. You could attach the Stirling engine crankshaft to a gear/alternator system to generate electricity. Or you could make a simple waterscrew to pump water!

Alas, I was not able to finish tweaking mine before I had to leave for Panama, but I learned a lot from it and plan on finishing this one when I get back. It will need a lot more black pipes to cover more surface area in order to be functional. But Stirling engines do work. Here's how to make a small one powered by a candle.

It took me a month of planning and designing to end up with the final product, but if you had the tools and materials you need - you could easily use these plans to build one of these over a weekend. Let's get started.

Construction Materials:

(Note: Most of these can be sourced on the cheap from your local large hardware store, but if you live more than 20 miles away from one - or if you don't have access to a truck to transport everything - you can save yourself the gas and trouble by purchasing them online from the links below. I've spent a solid 8 hours searching out these materials at cheap prices and from reliable sellers.)

• Cardboard 
• You can get this in bulk for free from recycling centers, behind grocery stores or any other store really (Maybe from your own shipping boxes?).
•  Online Link: Cardboard
• EMT Pipe
• My local Lowes sells 10 foot sections of this for $2.00! I've found that they are incredibly useful for a wide range of DIY projects (broom handles, curtain rods, water fountains, etc.)
• Online here: 1/2 inch EMT
• CPVC Pipe
• CPVC is primarily used for hot water and can be purchased at hardware stores for about $4 per 8 foot section. We are using CPVC here because of it's proximity to the hot metal pipes. We'll also be using it for the thermal solar frame because it's cheap and, for most people, it's easier to work with than wood.
• Online Link: 2ft sections of CPVC
• If you buy the 2 foot sections, you'll need some couplings to make them longer: Coupling
• Note, make sure you change the size to 1/2 inch
• Also note, these are not CPVC, but PVC, they're for the frame and not directly exposed to the heat, so it should be OK.
• Alternatively: 10ft Sections But you'll have to pick them up. 
• CPVC 90 Degree Elbows
• I actually think it's cheaper to get them online: 90 Degree Elbows 
• CPVC Tee
• Online Link: CPVC Tee 
• CPVC Cap
• Also possibly cheaper to buy online: CPVC Cap 
• CPVC Cement
•  Online Link: CPVC Cement
• Hose Clamps
• Online Link: Hose Clamps
• Less effective, but cheaper alternative: Zip Ties
• Bicycle Inner Tube
• You're going to be cutting this into pieces, so it's best if you can find a punctured one somewhere for free. If you don't have one, ask a neighbor who owns a bicycle or check with your local bike shop.
• Online Link (new):  Bicycle Inner Tube 
• Flat Black Paint
• You'll be using this to paint the metal pipe black to increase it's albedo effect. You can get the basic stuff from Walmart for under $1
• This one is heat resistant: Black Paint for Engines 
• Strong Glue
• You'll want something that attaches to paper and metal. I don't recommend gorilla glue because expands and will wringle your aluminum sheets.
• Online Link: Welder Glue 
• Aluminum Foil
• This is what we are using as reflective material. It's actually one of the most thermally reflective materials on Earth! Alternatively, for a bigger boost, you could use mirrors obtained from a secondhand store.
• More foil than you will ever need in a lifetime (at a great price!): Aluminum Foil 
• 14 Gauge Wire
• The best and cheapest place to get this is in your closet. Metal wire hangers provide just enough of the material you need. Some Walmart stores also have "child safe wire hangers" that are steel wire wrapped in vinyl and sell for under $2 for a set of 10.
• If you need a lot of wire, however, this is a really, really good price on 200 feet of steel wire: 14 Gauge Steel Wire- it would be awesome for anyone who has wire fences.
• Tarp (Optional)
• This is just one of many options you can use as the walls of the perimeter of the thermal solar panel (aka solar oven). Another option (what I'll be using) is cardboard, but cardboard isn't waterproof. For a more expensive, finished look, you could use acrylic sheeting, plywood, or even aluminum sheeting. If you saw optional and totally skipped this bullet, don't worry, I'll tell you to come back and read this later on when we talk about the perimeter.
• Online link: Tarp  
• Condom
• Yea, that's right - a condom. You know, that thing that's been sitting in your wallet for the past 2 years? Well, now you can finally put it to good use! Besides, if it really has been there for that long, it probably needs to be changed out anyway. You could use a balloon, rubber glove finger, or anything else easily inflatable - but out of everything else I tested, I found that a condom provides better directional thrust and maintains it's integrity better than other options within it's price range. In this case, the thicker - the better.

Tools You'll Need:

If you're the avid hobbyist or woodworker, you probably have everything you need already. But, just in case, I'm going to assume you don't have any tools and set you up with exactly what I needed for this project.

• Drill and Saw - I'm just going to put this out there. This Porter Cable set is THE best set for this price range. I purchased it over 2 years ago, use them often, and they're both going strong. Bonus! The bag they come in can double as the handyman bag for most of your other tools. However, be aware that the NiCad batteries should be drained down as low as you can get them before you recharge them if you want to make them last.
• Spade Drill Bit Set
• Regular Drill Bit Set
• Multitool (Optional) - The ultimate LifeProTip - I never leave the house without mine. You'll be amazed how often you'll end up using this in a pinch. We'll really be utilizing it for it's screwdriver and pliers. So if you have those already, you won't need a Gerber life-simplifying device...this time.
• Metal Cutting Snips
• Large File 
• Tape Measure
• Rubber Mallet
• Hacksaw
• 1/2 Inch Pipe Cutter 
• Large Metal Toothed Table Vise (Optional) - The best advice I can give you is get a vice. All puns aside, a vice will make your life a lot easier, especially when bending and cutting the tubular steel. A table mounted one would work best, because it won't shift while you are using it, but it you don't want to drill holes into your table, you could use this 6'' Clamp-On Bench Vise

Alright, that's it! Now we have all of the materials we need. So let's do this!


Click Here for Part Two