One way that air conditioners try to stand out is by being quiet, and the bulk of noise comes from the fans and the compressor. One unit (the Haier Serenity) aimed to be the quietest unit possible, but while this effort had mixed results at best it is still interesting to see [Josh] give a tour of the different ways they tried to reduce noise (YouTube, embedded below). Noise-limiting elements include the unusual step of using separate motors for the indoor and outdoor fans, and even little counterweights to ensure they are perfectly balanced, just like wheel weights on automobile tires.
Another notable air conditioner is the Zero Breeze, a portable unit that was the product of a Kickstarter campaign. Features included (either bizarrely or predictably, you be the judge) a bluetooth speaker and an LED flashlight. [Josh] more than half suspected the product would never actually ship, but was pleasantly surprised. Not only did it deliver, it turned out to be a pretty nice design with only a couple of mildly head scratching moments (YouTube, also embedded below).
The build starts by disassembling the compressor, which contains three double-sided pistons. The housing is drilled with ports to allow gas to flow into and out of the cylinders, as well as to transfer from one side of the piston to the other. Acrylic end plates are fitted to the assembly. One end acts as an intake manifold, delivering air and fuel to the cylinders. The other side acts as the cylinder head, mounting the sparkplugs. Everything is then connected with acrylic tubing and a small square section of acrylic is turned into a carburetor to supply the air-fuel mix. Ignition is handled by coils triggered by the movement of the flywheel.
After an initial failure due to the acrylic manifold cracking, a stronger part is fabricated, and the engine bursts into life. The acrylic end caps give a great view of the combustion process in action. We’d love to see the a dyno graph on how much power and torque the unit puts out, or to see it hooked up to a bicycle or cart.
While performance of the original setup was good, [Eric] desired a compressor with more capacity for his resin casting activities. A 15 gallon air tank was sourced from a damaged Craftsman brand compressor, and pressed into service. The build involved plenty of sheet metal work to mount the various components, as well as an upgrade to the pressure regulator.
During the refit, [Eric] takes the time to answer questions from the audience about his original build. He notes that the fridge compressor has worked well without using any noticeable amount of oil, and that there was a problem with water build up in the original tank which has been solved in the new rig.
There are some parts of the world where living without air conditioning borders on unthinkable. But in more moderate climates, it isn’t all that unusual. [Josh’s] apartment doesn’t have central air conditioning — the kind that connects to a forced-air heating/cooling system. It does, though, have a water circuit for air conditioning, so he decided to hack a few experimental air conditioners.
He’s not starting completely from scratch. The two attempts he made at building his AC came from donor parts. The successful one started out as a hot water heater. The very first attempt didn’t quite work as well, using a refrigerator compressor and an evaporator from a baseboard heater. The flow control through the heat exchanger turns out to be very tricky, so [Josh] claims he mostly got ice right at the inlet and minimal cooling through the evaporator.
The more successful one works better but still has a problem with the evaporator freezing that he’s trying to solve. He’s looking for suggestions on how to make it work better. As much as we like a good hack, our advice is to move to a different apartment building.
There’s nothing like a true hack, where something useful is concocted from bits of scrap and bargain store finds. Builds like these are much more than the sum of their parts, especially when they result in a useful tool, like this DIY vacuum chamber that’s good for all sorts of jobs.
Everything [Black Beard Projects] used to accomplish this build is readily available almost everywhere in the world, although we have to note that appliance recycling efforts and refrigerant recovery programs have made it somewhat harder to lay hands on things like the old fridge compressor used here. The big steel cooking pot is an easy thrift store find, though, and while [Black Beard] used high-quality stainless fittings and valves to plumb the chamber, pretty much any cheap fittings will do.
The one sketchy area of the build is the plexiglass sheet used for the chamber top, which seems a little on the thin side to us. You can see it flexing in the video below as vacuum is pulled; it survived, but we can see it failing catastrophically at some point. We stand ready to be reassured in the comments. Still, it’s a tidy build with a few nice details, like wiring a switch into the old start capacitor box and using car door edge protector as a gasket on the chamber.
The build starts with an unlikely source for parts – an old automotive AC compressor. The one that [Made in Poland] chose to sacrifice was particularly nasty and greasy, but after popping off the pulley, the treasure within was revealed: the large, ring-shaped clutch electromagnet. Liberated from the compressor, the electromagnet was attached to a small frame holding a pillow block. That acts as an axis for an adjustable-length arm, the other end of which holds a modified angle grinder. In use, the electromagnet is powered up by a small 12-volt power supply, fixing the jig in place on the stock. The angle grinder is traced around and makes a surprisingly clean cut. Check out the build and the tool in use in the video below.
At the time [Made in Poland] recorded the video, he noted that he did not have a plasma cutter. That appears to have changed lately, so perhaps he’ll swap out the angle grinder for plasma. And maybe he’ll motorize it for even smoother cuts.
This one is clearly from the “it’s all fun and games until someone loses an eye” file, and it’s a bit of a departure from [Make It Extreme]’s usual focus on building tools for the shop. But what’s the point of having a well-equipped shop if you don’t build cool things, like this unique homebrew electric gun?
When we hear “electric gun” around here, we naturally think of the rail guns and coil guns we feature on a regular basis, which use stored electric charge to accelerate a projectile using electromagnetic forces. This gun is much simpler than that, using purely mechanical means to accelerate the projectiles. The heart of the unit is a machined aluminum spiral from an old scroll compressor, which uses interleaved orbiting spirals to compress gasses. This scroll was cut down to reduce its mass and fixed to a complex shaft assembly allowing it to spin up to tremendous speed with a powerful electric motor. A hopper feeds the marble-sized ammo into the eye of the scroll, which spits it out at high speed. Lacking a barrel, the gun can only spew rounds in the general direction of the target, but it makes up for inaccuracy with an impressive rate of fire — 100 rounds downrange in two seconds. It’s pretty powerful, too, judging by the divots in the sheet steel target in the video below.