Most of modern society’s energy usage is spent on heating in some form, whether it is to heat water, raise the temperature in a room, or for use in industrial processes. This makes it an excellent target for improvements in efficiency and resilience, as well as in the effort to decarbonize the world’s energy production. Here district heating and similar solutions are likely to play a major role in the near future.
Over the past decades, a number of nations have either already built out extensive district heating grids, or are in the process of doing so. The main advantage of these heating grids is that they not only allow for more efficient, centralized generating of heat, but also allow for e.g. industrial waste heat to be used productively rather than wasted, even if most of the heat will come from either dedicated or cogeneration thermal plants.
Recently, district heating has received a big push in e.g. China in the form of nuclear cogeneration, while the potential of using thermal storage to buffer heat for later use along with the concept of tying data centers into heating grids are also being explored. Although district heating is hardly new, it may help to ease humanity into a low-carbon future, without losing a bit of comfort.
Ask the average person about steam power and they’ll probably imagine a bygone era, a time when the sky was thick with smoke belched out by coal-burning locomotives and paddle-wheel ships. Steam is ancient technology they’ll say, and has as much to do with modern living as the penny-farthing.
Naturally, the real story is a bit more complex than that. Sure the reciprocating steam engine has fallen out of favor as a means of propulsion, but the concept of running machinery with steam is alive and well. In fact, unless you’re running on wind or solar power, there’s an excellent chance that a steam turbine is responsible for keeping the lights on in your house.
In honor of all things steam, we invited Quinn Dunki to host this week’s Hack Chat. Those who follow her exploits on YouTube will know that over the last several years she’s built a number of steam engines, from miniature scratch-built models to commercial kits that can do useful work. Who better to answer your burning steaming questions?
The first questions in the Chat were logical enough, with several users wanting to know just how hard it is to build a functional steam engine if you don’t have access to a mill or other means of high precision machining. According to Quinn, while better equipment will certainly allow you to build a more powerful and efficient engine, the basic premise is so simple that it doesn’t take much to get one going. If you’ve got a mini lathe and some bar stock, you’re half way there. In fact, they are so forgiving that she opines you’d struggle to build a steam engine that didn’t at least turn over — though that doesn’t mean it will necessarily run well.
Naturally some comparisons were drawn between the complexity of building a steam engine and putting together a small internal combustion engine (ICE). But while they might seem conceptually similar, Quinn cautions that building a working ICE from scratch is far more difficult and dangerous. She explains that steam engines have a tendency to fail gracefully, that is, mistakes in the design or poor tolerances generally result in little worse than wasted steam and extra noise. Comparatively, a faulty ICE design could easily turn into a bomb on your workbench.
Of course, that’s not to say working with steam is without danger. You certainly don’t want to underestimate high pressure steam, which is why boilers that are over 6 in (15 cm) in diameter or that produce more than 100 PSI will often require the operator to be licensed. They may also need to be inspected, though Quinn notes that your local government official probably won’t be able to make heads or tails of your homebrew build — so if you need an official stamp of approval, your best bet is to find a local model engineering club or society that would have the appropriate connections. All that being said, most hobbyists make it a point to try and get their engine running at the lowest pressure possible, so unless you’ve got something really massive in mind, you’ll probably never need to build up more than 60 PSI or so.
A DIY electric boiler and small steam engine.
Another topic of discussion was how to fuel the boiler itself. An electrically powered boiler is perhaps the easiest option, but is somewhat counterproductive if you hope to put your steam engine to useful work. Coal and wood fires are an option, and indeed were commonly used in the old days, but the soot and ash they produce can be a problem.
Quinn also notes that if you’re using such fuels, you need a way to quickly remove the firebox from the boiler in an emergency; something she likens to the starship Enterprise having to eject its warp core before it explodes. For her own projects, Quinn says she uses either an electric element or a camping gas burner.
While most of the questions during this Hack Chat had to do with the work Quinn has already featured on her blog and YouTube channel, naturally there were questions about where things go from here. After she completes the steam engine kit she’s working on currently, she says she’ll likely to back to another scratch-built engine. She also plans on coupling some of her engines to generators, as she’s gotten many requests about seeing these machines put to useful work. Looking further ahead Quinn says she’s interested in casting her own bronze and aluminum components, and specifically wants to work with “lost PLA” casting, which is a variant of lost wax casting that uses a mold based on a 3D printed part.
We’d like to thank Quinn Dunki for stopping by the Hack Chat and sharing some insights into this unique hobby. While a handcrafted boiler or a desktop steam reciprocating engine might not be on the average Hackaday reader’s list of future projects, it’s still fascinating to see how they work. We owe much of our modern life to steam power, so the least we can do is show it some respect.
The Hack Chat is a weekly online chat session hosted by leading experts from all corners of the hardware hacking universe. It’s a great way for hackers connect in a fun and informal way, but if you can’t make it live, these overview posts as well as the transcripts posted to Hackaday.io make sure you don’t miss out.
[shoobs] relocated from Australia to Luxembourg, and was really missing the whole outdoor cooking scene that is apparently very common in those parts. Now living in a modest apartment building in the city, he had no easy way to recreate some of his favorite cooking methods — specifically that of Wok Hei (breath of a wok) — the art of Cantonese stir-frying which uses searing heat and a lot of flinging around of the food to mix it up with the burning oil. This results in a complex set of reactions utilizing smoking, caramelization, and Maillard reactions to produce the classic Cantonese smoky flavor. Not wanting an off-the-shelf solution [shoobs] took it on himself to build a balcony cooking station capable of the temperatures needed for Wok Hei, and documented it for our viewing pleasure.
Nice custom laser cut details on the regulator mounting
The build started with sourcing a free-standing burner unit from Alibaba, which proved to be a little less powerful (at 30 kW) than ideal, but still sufficient. After locating a matching regulator and pressure gauge capable of the needed flow rate to feed the hungry burner, the next task was to construct a sturdy enough bench to mount it all. This was constructed from Douglas fir slabs, butt-jointed using a 3D printed drilling jig for ease of construction.
Using a flatbed scanner, the existing burner base was digitized in order to make a model suitable for laser-cutting a new mounting plate from steel. [Shoobs] isn’t lucky enough to have access to a metal-capable laser cutter — he sent his cad files off to a cutting service.
A second plate was mounted below with a sufficient gap above the bench to act as a heat shield. This keeps the wooden worktop safe from the heat. Whilst he was laser cutting steel, [shoobs] took the opportunity to design a few other custom parts to mount the regulator and other bits, because, why wouldn’t you? We reckon the end result is pretty nice, in a minimalist and understated way.
We’re no strangers to neat cooking hacks ’round these parts, here’s a nice double-sausage burner for those emergency situations and if you need a custom BBQ burner, then look no further.
We start this week with news from Mars, because, let’s face it, the news from this planet isn’t all that much fun lately. But a couple of milestones were reached on the Red Planet, the first being the arrival of Perseverance at the ancient river delta it was sent there to explore. The rover certainly took the scenic route to get there, having covered 10.6 km over the last 424 sols to move to a position only about 3.5 km straight-line distance from where it landed. Granted, a lot of that extra driving was in support of the unexpectedly successful Ingenuity demonstration, plus taking time for a lot of pit stops along the way at interesting features. But the rover is now in place to examine sedimentary rocks most likely to harbor the fossil remains of ancient aquatic life — as opposed to the mainly igneous rocks it has studied along the crater floor so far. We’re looking forward to seeing what happens.
Most of us probably have some vivid memories of high school or college chemistry lab, where the principles of the science were demonstrated, and where we all got at least a little practice in experimental methods. Measuring, diluting, precipitating, titrating, all generally conducted under safe conditions using stuff that wasn’t likely to blow up or burn.
But dropwise additions and reaction volumes measured in milliliters are not the stuff upon which to build a global economy that feeds, clothes, and provides for eight billion people. For chemistry to go beyond the lab, it needs to be scaled up, often to a point that’s hard to conceptualize. Big chemistry and big engineering go hand in hand, delivering processes that transform the simplest, most abundant substances into the things that, for better or worse, make life possible.
To get a better idea of how big chemistry does that, we’re going to take a look at one simple molecule that we’ve probably all used at one time or another: the common artificial flavoring wintergreen. It’s an innocuous ingredient in a wide range of foods and medicines, but the infrastructure required to make it and all its precursors is a snapshot of just how important big chemistry really is.
Many readers will be familiar with the Dyson Air Multiplier, an ingenious bladeless fan design in which a compressor pushes jets of air from the inside edge of a large ring. This fast-moving air draws the surrounding air through the ring, giving the effect of a large conventional fan without any visible moving parts and in a small package. It’s left to [Integza] to take this idea and see it as the compressor for a jet engine, and though the prototype you see in the video below is fragile and prone to melting, it shows some promise.
His design copies the layout of a Dyson with the compressor underneath the ring, with a gas injector and igniter immediately above it. The burning gas-air mixture passes through the jets and draws the extra air through the ring, eventually forming a roaring jet engine flame exhaust behind it. Unfortunately the choice of 3D print for the prototype leads to very short run times before melting, but it’s possible to see it working during that brief window. Future work will involve a non-combustible construction, but his early efforts were unsatisfactory.
It’s clear that he hasn’t created the equivalent of a conventional turbojet. Since it appears that its operation happens when the flame has passed into the center of the ring, it has more in common with a ramjet that gains its required air velocity with the help of extra energy from an external compressor. Whether he’s created an interesting toy or a useful idea remains to be answered, but it’s certainly an entertaining video to watch.
Tomorrow is Thanksgiving and that means Americans across the United States will be cooking up a turkey feast. One of the most popular ways to cook the bird is by deep frying it in oil.
Local TV stations everywhere spend this week warning about turkey frying. They’re not wrong… if things get out of hand you can end up burning down your house, if not your entire street. Let’s talk the science behind November turkey fires, and hopefully avoid a turkeyferno.
Simple Errors
The typical setup for deep frying a turkey involves lowering the bird into a big pot full of oil sitting on a gas burner. Ropes and pulleys are often used to lower the turkey into the pot to avoid getting one’s hands near the hot oil. Ideally, this should be done in a backyard, away from structures, to provide good ventilation and plenty of room in the case something does go wrong.
