DIY Air Conditioner Built From Weird Donor Appliance

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.

We’ve seen other homemade coolers, but they are more like swamp coolers. If you just need to cool your desk, you might just get some ice in a metal can.

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Drag Your Office Aircon Into The 21st Century With Wi-Fi Control

We’ll all have worked in offices that have air-conditioning, but a little too much of it. It’s wonderful on a baking-hot day to walk into the blessèd cool of an air-conditioned office, but after an hour or two of the icy blast you’re shivering away in your summer clothing and you skin has dried out to a crisp. Meanwhile on the other side of the building [Ted] from Marketing has cranked up the whole system to its extreme because he’s got a high metabolism and an office in the full force of the midday sun.

Wouldn’t it be nice if individual air-conditioning units could be easily controlled. To that end, [Maya Posch] has made a rather nicely designed board that takes a NodeMCU board with its ESP8266 processor, and uses four of its outputs as PWM to produce 0-10 volt analogue outputs via filters and op-amps to control individual units. In addition there is an onboard CO2 sensor and a temperature sensor, with provision for an external temperature sensor. The whole fits very neatly into a standard electrical outlet enclosure.

Software wise, the system uses the Sming framework providing an MQTT  communication with a backend server that allows the users to control their aircon experience. This is very much a work in progress, so the software has yet to be put up. (Hint, [Maya], hint!) The whole project though is an extremely tidy build, in fact a thing of beauty to a standard you’d expect from a high-quality commercial product. It’s this that tipped the balance into our featuring it before the software is released, it’s one to keep an eye on, because quality like this doesn’t come every day.

This isn’t the first aircon control we’ve brought you, take a look at this one controlled through Slack.

Control The Air Conditioning With Slack

[Raphael Baron] needed a better way to control his office’s air conditioning units. Sure, they have remotes, but that’s too easy. [Raphael] came up with a solution that uses an ESP8266, a computer, IR LEDs, and a bot that runs on Slack.

[Raphael] built a prototype of the ESP8266 hardware on protoboard and used it to read and record the IR signals from the remote. Once he’d figured out the issues he was having with the IR library he was using, he could use it to send the IR commands to the AC unit. Since their office has two AC units, [Raphael] built a second prototype which had two IR LEDs but didn’t have the IR receiver. Using this he could turn both AC units on and off and set their temperatures.

For the server, [Raphael] turned to Clojure, a dialect of Lisp, which provides easy access to the Java Framework, mainly to get practice working with the language. The server’s main responsibility is to use Slack’s real-time API to listen for messages from a Slack bot and forward them to the ESP. In this way, a user talking to the Slack bot can send it messages which the server forwards to the microcontroller which, in turn, parses the messages and send IR commands to the AC units.

[Raphael] admits that this isn’t the most advanced, professional stuff, but it doesn’t matter. The schematics for the ESP8266 board and the code for both the ESP board and the server are available on GitHub. There seems to be a lot of hacks using Slack, such as this NERF Turret controlled by a Slack bot.  Or this jukebox that users can interact with by talking to a Slack bot.

Hackaday Prize Semifinalist: Portable A/C

Many people with Multiple Sclerosis have sensitivity to heat. When the core body temperature of an MS sufferer rises, symptoms get worse, leading to fatigue, weakness, pain, and numbness. For his entry to the Hackaday Prize, [extremerockets] is finding a solution. He’s developing a wearable, personal cooling device that keeps the wearer at a comfortable temperature.

The device is based on a wearable shirt outfitted with small tubes filled with a cooling gel. This setup is extremely similar to the inner garments worn by astronauts on spacewalks, and is the smallest and most efficient way to keep a person’s core body temperature down.

Unlike a lot of projects dealing with heating and cooling, [extremerockets] isn’t working with Peltiers or thermoelectric modules; they’re terribly inefficient and not the right engineering choice for something that’s going to be battery-powered. Instead, [extremerockets] is building a miniature refrigeration unit, complete with a real refrigeration cycle. There are compressors, valves, and heat exchanges in this build, demonstrating that [extremerockets] has at least some idea what he’s doing. It’s a great project, and one we can’t wait to see a working prototype of.

The 2015 Hackaday Prize is sponsored by:

DIY AC for the Hot Shop

Working out in the shop is usually super fun but if it’s summertime, watch out, it can get hot! We’ve all been there and we’ve all wished we could do something about it. Well, woodworker and general DIYer [April] has stepped up to the plate and built a portable low-buck AC unit to cool her shop down to an acceptable temperature.

The unit is very simple and starts off with an old thrift store cooler. A hole is cut in the back of the cooler to make room for a fan that is directed to blow air inside the cooler and across blocks of ice. The air cools down as it passes over the ice and leaves out the top of the cooler through five 90-degree PVC elbows. After all the inlets and outlets were caulked, the entire unit was given a monochromatic black paint job.

[April] says you can feel the cool air blowing from about 5 feet away from the unit. She has measured the output air temperature to be 58-62ºF. If using loose ice cubes, the unit will work for 2-3 hours. Freezing milk jugs full of water gets about 5 hours of use.

Zero-Dollar AC System Looks Funny But Works Well

Summer is here and with summer comes hot days. You probably know that us humans get uncomfortable if the temperature rises too much. Sure, we could turn on the loud and inefficient window AC unit and try to stay mildly comfortable while the electric company pick-pockets pennies from our change purse, but what is the fun in that? [Fran] had a better idea.

He noticed that his basement was always in the upper 50°F range regardless of how hot it was outside. He wanted the cool basement air to reside upstairs in the living area. After thinking long and hard about it he decided that a box fan and two long, skinny cardboard boxes assembled together would be enough to move the required amount of air. Both the fan and boxes were kicking around the house so was no cost and no risk to try this out. Continue reading “Zero-Dollar AC System Looks Funny But Works Well”

A Low Cost, Solar-Powered Swamp Cooler

A looming, torturous summer is preparing to bear down on many of us, making this dirt-cheap swamp cooler build an attractive hack to fend off the heat.

Though this is a pretty standard evaporative cooler, the design comes together in a tidy and transportable finished product. The base is a ~$3, 5-gallon bucket from a local hardware store with its accompanying Styrofoam liner. Three 2 1/8″ holes carved into the side of both the bucket and liner will snugly fit some inch-and-a-half PVC pipe with no need for glue.

One last cut into the lid to seat a small desk fan rounds off this build—or you can chop into the styrofoam liner’s lid if you prefer. The video demonstrates using a 15W solar panel to run the fan, and we have to admit that the cooler seems to be an excellent low-cost build. It does, however, require a frozen gallon jug inside to pump out the chilled air for around 5-6 hours per jug. Maybe one of our frugal and mathematically-inclined readers can throw out some guesstimations for the cost of stocking the bucket with a jug of frozen water a couple times a day? Video after the jump.

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