Heat Pump Dryer Explained

Historically, having a washer and a dryer in your house requires “a hookup.” You need hot and cold water for the washer as well as a drain for wastewater. For the dryer, you need either gas or — in the US — a special 220 V outlet because the heating elements require a lot of wattage, and doubling the voltage keeps the current levels manageable. You also need a bulky hose to vent hot moist air out of the house. But a relatively new technology is changing that. Instead of using a heater, these new dryers use a heat pump, and [Matt Ferrell] shows us his dryer and discusses the pros and cons in a video you can below. We liked it because it did get into a bit of detail about the principle of operation.

These dryers are attractive because they use less power and don’t require gas or a 220 V outlet. They also don’t need a vent hose which means they can sit much closer to the wall and take up less space. Heat pumps don’t convert electrical energy into heat like a normal heating element. Instead, it uses a compressor to move heat from one place to another. In this case, the dryer heats the air using the heat pump. That causes water in the clothes to evaporate into the air. The heat pump dryer then uses a second loop to cool the air, condensing the water out so the it can reheat the air and start the whole cycle over again.

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2023 Halloween Hackfest: This Year’s Spooky Winners

With the zombies, ghouls, and ghosts now safely returned to their crypts until next October, it’s time to unveil this year’s winners for the 2023 Halloween Hackfest.

For this contest, sponsors DigiKey and Arduino challenged the community to come up with their best creations for what’s arguably the most hacker-friendly of holidays. Pretty much everything was fair game, from costumes to decorations. The top three winners will get $150 credit from DigiKey and some treats from Arduino — just don’t try to eat them.

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Who Needs Gasoline When You’ve Got Sodium?

YouTuber and serial debunker [Thunderf00t] was thinking about the use of sodium to counteract global warming. The theory is that sodium can be used as a fuel when combusted with air, producing a cloud of sodium hydroxide which apparently can have a cooling effect if enough of it is kicking around the upper atmosphere. The idea is to either use sodium directly as a fuel, or as a fuel additive, to increase the aerosol content of vehicle emissions and maybe reduce their impact a little.

One slight complication to using sodium as a fuel is that it’s solid at room temperature, so it would need to be either delivered as pellets or in liquid form. That’s not a major hurdle as the melting point is a smidge below 100 degrees Celsius and well within the operating region of an internal combustion engine, but you can imagine the impact of metal solidifying in your fuel system. Luckily, just like with solder eutectic mixes, sodium-potassium alloy happens to remain in liquid form at handleable temperatures and only has a slight tendency to spontaneously ignite. So that’s good.

Initial experiments using ultrasonic evaporators proved somewhat unsuccessful due to the alloy’s electrical conductivity and tendency to set everything on fire. The next attempt was using a standard automotive fuel injector from the petrol version of the Ford Fiesta. Using a suitable container, a three-way valve to allow the introduction of fuels, and an inert argon feed (preventing spontaneous combustion in the air), delivering the liquid metal fuel into the fuel injector seems straightforward enough.

[Thunderf00t] started with ethanol, then worked up to pentane before finally attempting to use the feisty sodium-potassium, once the bugs had been shaken out of the high-speed video setup. [Thunderf00t] does stress the importance of materials selection when handling this potential liquid metal fuel, since it apparently just bursts into flames in a violent manner on contact with incompatible materials. Heck, this stuff even reacts with PTFE, which is generally considered a very resistant material. We’re totally convinced we’d not like to see this stuff being pumped from a roadside gas station, at all, but it sure is a fun concept to think about.

Sodium-Potassium alloy doesn’t feature on these pages too often, but here’s a little fountain of the stuff, just because why not?

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Big Chemistry: Liquefied Natural Gas

The topic of energy has been top-of-mind for us since the first of our ancestors came down out of the trees looking for something to eat that wouldn’t eat them. But in a world where the neverending struggle for energy has been abstracted away to the flick of a finger on a light switch or thermostat, thanks to geopolitical forces many of us are now facing the wrath of winter with a completely different outlook on what it takes to stay warm.

The problem isn’t necessarily that we don’t have enough energy, it’s more that what we have is neither evenly distributed nor easily obtained. Moving energy from where it’s produced to where it’s needed is rarely a simple matter, and often poses significant and interesting engineering challenges. This is especially true for sources of energy that don’t pack a lot of punch into a small space, like natural gas. Getting it across a continent is challenging enough; getting it across an ocean is another thing altogether, and that’s where liquefied natural gas, or LNG, comes into the picture.

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EV Chargers Could Be A Serious Target For Hackers

Computers! They’re in everything these days. Everything from thermostats to fridges and even window blinds are now on the Internet, and that makes them all ripe for hacking.

Electric vehicle chargers are becoming a part of regular life. They too are connected devices, and thus pose a security risk if not designed and maintained properly. As with so many other devices on the Internet of Things, the truth is anything but. 

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How Resilient Is The Natural Gas Grid?

A few years ago, I managed to get myself on a mailing list from a fellow who fancied himself an expert on energy. Actually, it seemed that no area was beyond his expertise, and the fact that EVERY EMAIL FROM HIM CAME WITH A SUBJECT LINE IN CAPS WITH A LOT OF EXCLAMATION POINTS!!!! really sealed the deal on his bona fides. One of the facts he liked to tout was that natural gas was the perfect fuel. Not only is it clean-burning and relatively cheap, it’s also delivered directly to consumers using a completely self-powered grid. Even under “zombie apocalypse” conditions, he claimed that natural gas would continue to flow.

At the time, it seemed a bit overstated, but I figured that there was at least a nugget of truth to it — enough so that I converted from an electric range and water heater to gas-powered appliances a couple of years ago, and added gas fireplaces for supplemental heat. I just sort of took it for granted that the gas would flow, at least until the recent kerfuffle over the Nordstream pipeline. That’s when I got a look at pictures of the immense turbine compressors needed to run that pipeline, the size and complexity of which seem to put the lie to claims about the self-powered nature of natural gas grids.

Surely a system dependent on such equipment could not be entirely self-powered, right? This question and others swirled doubt in my mind, and so I did what I always do in these cases: I decided to write an article so I could look into the details. Here’s what I found out about how natural gas distribution works, at least in North America.

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Ask Hackaday: How Can You Store Energy At Home?

Amidst the discussions about grid-level energy storage solutions, it is often easy to forget that energy storage can be done on the level of a single house or building as well. The advantages here are that no grid management is needed, with the storage (electrical, thermal, etc.) absorbing the energy as it becomes available, and discharging it when requested. This simplifies the scale of the problem and thus the associated costs significantly.

Perhaps the most common examples of such systems are solar thermal collectors with an associated hot water storage tank, and of course batteries. More recently, the idea of using a battery electric vehicle (BEV, ‘electric car’) as part of a home storage solution is also gaining traction, especially for emergencies where the grid connection has failed due to a storm or similar emergencies. But all-in-all, we don’t see many options for home-level energy storage.

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