Modern internal combustion engines have around 500 parts, with many of them moving in concert with the piston. But have you seen an engine with only one moving part, out of four in total? In the thermoacoustic engine, the power piston is the only part in motion. [YTEngineer] has built a very simple prototype that works on power provided by a tealight.
His little engine, slightly larger than a cigarette lighter, is composed of a test tube that serves as the cylinder, a smaller tube, called the choke, that fits inside the test tube, the stack, which is nothing more than some steel wool, and the power piston. [YTEnginer] nicely explains how the engine works: basically a temperature difference is used to induce high-amplitude sound waves that create the piston’s back-and-forth movement. The engine can be easily converted to an electricity generator by adding a magnet to the piston and a coil surrounding it.
The thermoacoustic engine is a particular type of Stirling engine. They have been proposed as electricity generators for space travel using radioisotopes as the heat source, among other applications. You may be interested in the history of Stirling engines, or perhaps even build a simple one.
It’s no secret that fossil fuels are quickly becoming extinct. As technology charges ever forward, they are disappearing faster and faster. Many of our current dependencies on fossil fuels are associated with high-energy applications like transportation. Since it’s unlikely that global transportation will ever be in decline for any reason other than fuel shortage itself, it’s imperative that we find something that can replicate the high energy density of fossil fuels. Either that, or go back to the drawing board and change the entire scope of global transportation.
Energy, especially solar and wind, cannot be created all over the world. Traditionally, energy is created in situ and shipped to other places that need it. The proposed solutions for zero-carbon energy carriers—batteries and hydrogen—all have their weaknesses. Batteries are a fairly safe option, but their energy density is pretty poor. Hydrogen’s energy density is higher, but its flammability makes it dangerously volatile to store and transport.
Recently, a group of researchers at McGill University in Canada released a paper exploring the use of metal powders as our zero-carbon fuel of the future. Although metal powders could potentially be used as primary energy sources, the transitory solution they propose is to use them as secondary sources powered by wind and solar primaries.
Last week we challenged you to post your idea on environment-related solutions for the 2015 Hackaday Prize. We’ve gone through every entry and have chosen this week’s winners. What a tough process, there are so many interesting ideas to consider that we’ve done a round-up of some that held our attention.
Bosch Haber Process
Energy Saving
Conservation was at the center of these projects and [Peter Walsh] is thinking large scale to improve the Bosch-Haber process. This process is used as a source of nitrogen for fertilizers and consumes 1% of all energy worldwide. Even small efficiency advances could have a huge effect.
From profound to whimsical, [TomaCzar] has an alarming solution to leaving the lights on. We enjoy his preamble about his family moving to Earth from a planet with unlimited energy (hence their habit of leaving the lights on). He plans to add an audible alarm to any light that is switched on for more than 10 minutes.
Energy Production
Those huge solar farms that use arrays of mirrors to focus the sun’s light on a central tower leverage a techique called Concentrated Solar Power. Traditionally they store heat in a pool of liquid salt for generating power around the clock. [PUNiSH3R] has a plan to build his own on a micro-scale. The Portable Micro-CHP will use similar concepts (less the molten salt) in a package small enough to be transported by a single human.
Undeveloped parts of the planet have huge problems when it comes to bootstrapping an electrical grid. [hickss] thinks blimps might be one way to alleviate the problem. The DayBreaker project will tether blimps to the ground, with a hydrogen feed supplied through electrolysis which keeps them afloat. While high in the air they can catch higher winds using a turbine and transfer the electricity back to the ground using the same tether.
Rounding out energy producing examples is the Domestic Geothermal Stirling Power Unit. We’ve seen geothermal systems that use heat exchangers to heat or cool your home. [Shrad] ponders the idea of also using the loops of circulating fluid to feed a Stirling engine that could help supply power to the home.
Way Out There Ideas
Is this parking lot a power plant waiting to happen?
There were a number of interesting concepts that we think are well worth considering and debating. It’s hard to say if these are all feasible, but tossing the ideas around is just the kind of interaction that could lead to a big breakthrough. For instance, the image seen here is a freshly paved and painted asphalt parking lot. Asphalt Heat Harvesting imagines the Peltier effect being used on a large scale by embedding metal networks between layers of the pavement. A heat differential between the surface and the base layer could produce electricity.
We’re at a loss for understanding how the Open Source Modular Absorption Refrigeration Unit actually works. It seeks to supply refrigeration using a heat source instead of electricity. The diagram looks promising and we think OSMARU is a solid acronym!
Remember The Hunt for Red October? If so, you certainly remember the caterpillar drive which made the submarine virtually silent. [N-Monkeys] wants to use that and ocean water as a generator rather than a locomotive device. Check out Project InchWorm.
Congratulations to all three! We think it’s important to mention we are judging the idea on its ability to solve something affecting a wide range of people, its level of innovation, and the feasibility of the concept. There is no requirement at this point to have built anything or completed the documentation. Don’t be afraid to write down your own brainstorm… it might just win you a prize!
Next Week’s Theme
We’ll announce next week’s theme a bit later today. Don’t let that stop you from entering any ideas collection of entries may have inspired.
Coming up with that killer concept is a matter to thinking in different ways and interacting with other Hackers, Designers, and Engineers to help make the mental leap to greatness!
Part of our whirlwind UK visit took us to Cambridge, where we had the joyous opportunity to check out Cambridge Makespace. The main space was formerly part of the Institute for Manufacturing Robot Lab at Cambridge University, so it has a long heritage of supporting engineering innovation. Continue reading “Hackerspace Tours: Cambridge Makespace”→
Watching [Jam BD] build this working Sterling Engine from nothing is awe-inspiring. He literally did with what he had on hand. Even his build log forgoes phrases like “I ordered a…” in exchange for “I didn’t have any so…”.
The cylinder heated by a candle is a pipe stuffed with aluminum foil which was hammered flat to get the best seal possible. The CDs prominently featured on the final product act as the fly-wheel. To ensure that there is enough mass [Jam] ganged three of them together. There is also a counter-weight affixed just off-center to help keep the wheel turning. The gears shown above were actually used more like mounting plates to build a cam. Looking at the body and frame of the device makes us wonder how in the heck this thing actually came together?
We know a lot about toggling bits in a register, but only a bit about how engines work. This one inspires us to throw ourselves into the field with reckless abandon. [Huib Visser] built this glass cylinder four-stroke engine and he took great care to make it beautiful. We don’t need our projects to be polished and gleaming, but we have to admit that this the opposite of what we see when popping the hood on our 12-year-old rust bucket out front.
You can’t see it in this image, but just on the other side of the fly-wheel is a smaller wheel with a cord wrapped around it that acts as the pull start. This gets the toothed timing belt going along with the cylinder. As part of the demo video we get a good look at how the rotary intake and exhaust valves work. [Huib] also took the time to demonstrate how the rare earth magnets and hall effect sensor reed switch synchronize the ignition system.
You won’t want to miss the end of the video which show it in action as It burns Coleman fuel (white gas) and is lubricated with WD-40. This is jaw dropping and it works like a charm, but still not that far removed from the concepts seen in [Lou’s] hardware store engine project.
This truck is not simply a drive train and a radio module. Great care was taken to fabricate every part to work like a full-sized vehicle. NSFW WARNING: The forum on which the details have been posted is Russian and may have sidebar ads you don’t want on your screen at work. That being said, here’s the link (translated).
The build starts with a custom-made frame which looks like it’s aluminum. The gearbox is assembled from a huge number of parts, with power is transferred to the wheels through a proper differential. But hey, why not go that extra mile? The rope and hook hanging off the front are connected to a functional winch. The doors have windows that crank down, the steering wheel moves when the wheels turn, and where would this thing be without windshield wipers and headlights? Don’t miss the pair of demo videos after the break.
