I’m always amazed that technology can totally wipe out industries. Sure, some people make a living making horseshoes, for example, but the demand for them is way down compared to what it would have been when horses were the normal mode of transportation. But even so, people still make horseshoes. But think about the ice harvesting business. Never heard of it? Turns out, before refrigeration, there was a huge business of moving ice from where it naturally occurred to other places and storing it, usually underground with a lot of insulation. As far as I know, that business — including the neighborhood ice man — is totally gone now except for some historical exhibitions. We take refrigeration and air conditioning for granted, but it hasn’t been that long ago that ice was a luxury and your own reprieve from the heat was a fan.
The story starts a little earlier than you might expect. In the 1840s, physician John Gorrie was concerned about “the evils of high temperature.” His hospital in Florida imported ice using the aforementioned ice trade and it wasn’t cheap nor was it very effective.
Undeterred, he developed a machine that used a horse, a waterwheel, steam, or wind power to drive a compressor to create ice. He got a patent in 1851 but it failed to catch on before his financial backer died. In fact, Oliver Evans had the idea in 1805 but never built a working machine. Jacob Perkins patented the first compression cooler in 1834, again with little practical use.
When U.S. President Garfield was shot, Navy engineers built a cooling box using cloths soaked in ice water to cool the president’s hospital room by 20 degrees. Since the mortally wounded president survived 80 days after the shooting, we presume he appreciated the comfort.
Continue reading “Tech In Plain Sight: Air Conditioning”
We’ll admit that the coolness factor of an air conditioned faux spacesuit made out of a hazmat suit will largely depend on where you wear it. At your next chess club meeting, maybe a hit. On a blind date, probably not. [Saveitforparts] apparently doesn’t mind and the combination of very warm weather and the donation of an expired hazmat suit, spurred his imagination as you can see in the video below.
A battery pack, a blower, and a box full of frozen water bottles completes the ensemble. Wireless temperature sensors show the outside temperature as well as temperature inside different parts of the suit. Does it work? We guess it must, but the roar of the fan is deafening and we have doubts about the frozen water cooling system. On the other hand, if you’re shooting a low budget science fiction thriller, this might be just the thing.
Even [Saveitforparts] admits this isn’t really practical and, as we suspected, he decided to get out of it as the condensing water started to run down his legs. Turns out astronauts and tank drivers use an undergarment made with small tubes of flowing water to stay cool.
This project reminded us of the positive pressure suit we saw a bit ago. Not to mention the one that went full body.
Continue reading “Even With AC, Hazmat Suit Isn’t Really Cool”
Portable air conditioning units are a great way to cool off a space during the hot summer months, but they require some place to blow the heat they’ve removed from your room. [VincentMakes] got a portable AC unit for his home, but he found that the place he wanted to put it was too far from the only window he could use to dump the hot air. Having too long of a duct on the hot air exhaust increases the back pressure on the fan which could cause it to prematurely fail, so [Vincent] used an extractor fan to automatically give is AC unit’s exhaust a boost on its way to the window.
Because his AC can operate at low, medium, and high speeds, he chose an extractor fan that also supported multiple speeds and took care to match the airflow of the AC and extractor fan to avoid putting too much strain on either fan. He designed a system to automatically set the speed of the boosting fan to match that of the AC using a Hall effect current sensor to measure the AC unit’s power draw and an Arduino Nano for control. A custom PCB interfaces the Nano to the Hall Sensor and control relays, and we have to applaud [Vincent] for keeping the +5V DC and 230V AC far, far away from each other. In addition to this fine electronics work, [Vincent] also built an enclosure for the fan controller that allows the fan to be mounted on top at an angle, which helps avoid having hard bends in the exhaust duct.
If this has you thinking about smart air conditioners to keep cool this summer, check out this ESP8266-powered smart AC system, or this Raspberry Pi-based system that controls both AC and blinds!
We never insist that a hack be practical. [Tech Ingredients] is living proof as they modded a computer case to use a window air conditioner for overclocking a computer. They think they haven’t hit the ceiling yet, and got their AMD Ryzen 8-core processor up to 4.58 GHz.
An advantage of forcing air from an air conditioner is that the air forced into the system is quite dry and clean. The trick is to create a simple duct to attach to a 5,000 BTU air conditioner. It doesn’t actually interface with the CPU cooling block, instead it just forces cool air into the case and this tends to cool everything inside. Admittedly, it isn’t any worse than plunging your computer in liquid nitrogen, and we’ll admit that air conditioning units are made to keep large areas cold and work at high duty cycles. With the air conditioning running, they disconnected at least some of the stock fans. The temperatures stayed cool even at high speeds.
Continue reading “PC Overclocking With An Air Conditioner”
If you live anywhere near the tropics, air conditioning isn’t a luxury but a necessity. The problem however is that humid climates can cause conventional air conditioners to draw more power to dehumidify the air than it requires to just cool it, which increases the power needed to run the unit. Back in 1963, there was a proposal to create a cooling system that didn’t foster condensation and couple it with different methods of removing humidity. Researchers in Singapore have now created such a system. It uses a membrane that is permeable to infrared radiation but prevents condensation around the cooling unit.
You can see a video of the apparatus in a pavilion in the Singapore heat in the video below. Chilled water runs through tubes behind a membrane that passes thermal radiation. Since the tubes are not exposed to the ambient atmosphere, condensation is minimal. But heat radiates from the warmer area to the much colder area of the tubes.
Continue reading “Cold Tube Draws The Heat”
Obviously, if the air filters in your home HVAC system are dirty, you should change them. But exactly how dirty is dirty? [Tim Rightnour] had heard it said that if you didn’t change your filter every month or so, it could have a detrimental effect on the system’s energy consumption. Thinking that sounded suspiciously like a rumor Big Filter™ would spread to bump up their sales, he decided to collect his own data and see if there was any truth to it.
There’s a number of ways you could tackle a project like this, but [Tim] wanted to keep it relatively simple. A pressure sensor on either side of the filter should tell him how much it’s restricting the airflow, and recording the wattage of the ventilation fan would give him an idea on roughly how hard the system was working.
Now [Tim] could have got this all set up and ran it for a couple months to see the values gradually change…but who’s got time for all that? Instead, he recorded data while he switched between a clean filter, a mildly dirty one, and one that should have been taken out back and shot. Each one got 10 minutes in the system to make its impression on the sensors, including a run with no filter at all to serve as a baseline.
The findings were somewhat surprising. While there was a sizable drop in airflow when the dirty filter was installed, [Tim] found the difference between the clean filter and mildly soiled filter was almost negligible. This would seem to indicate that there’s little value in preemptively changing your filter. Counter-intuitively, he also found that the energy consumption of the ventilation fan actually dropped by nearly 50 watts when the dirty filter was installed. So much for a clean filter keeping your energy bill lower.
With today’s cheap sensors and virtually infinite storage space to hold the data from them, we’re seeing hackers find all kinds of interesting trends in everyday life. While we don’t think your air filters are spying on you, we can’t say the same for those fancy new water meters.
If you’re looking for “smart” home appliances, there’s no shortage of options on the market. Even relatively low-end gadgets are jumping on the Internet of Things bandwagon these days (for better or for worse). But what if you’re not looking to purchase a brand new major appliance right now? In that case, you might be interested in seeing how [Giulio Pons] added some high-tech features to his existing air conditioner on the cheap.
Since his AC unit had an infrared remote control, the first thing [Giulio] needed to do was come up with a way to emulate it. An easy enough project using the ESP8266 and an IR LED, especially when he found that somebody had already written a IR communications library for his particular brand of AC. From there, he could start tacking on sensors and functionality.
With the addition of a DHT11 sensor, [Giulio] can have the AC turn on and off based on the current room temperature. It also gives him an easy way to verify the AC is actually on and operating. By checking to see if the room starts cooling off after sending the IR command to start the AC, his software can determine whether it should try resending the code, or maybe send a notification to alert him that something doesn’t seem right. Of course, it wouldn’t be a proper ESP8266 project without some Internet connectivity, so he’s also created a smartphone application that lets him control the system while away from home.
Now admittedly nothing in this project is exactly new, we’ve seen plenty of hackers switch on their AC with the ESP8266 at this point. But what we particularly liked was how well thought out and documented the whole process was. The rationale behind each decision is explained, and he even documented things like his network topology to help illustrate how the whole system comes together. Even if the techniques are well known by many of us, this is the kind of project documentation that makes it accessible to newcomers. Our hats off to [Giulio] for going the extra mile.
In the past we’ve seen a similar project that allowed you to control your AC from Slack, and our very own [Maya Posch] took us on a whirlwind tour of the very impressive ESP8266-powered environmental monitoring system she helped develop.