Making Coffee With Hydrogen

October 9, 2021 by Jenny List 17 Comments

Something of a Holy Grail among engineers with an interest in a low-carbon future is the idea of replacing fossil fuel gasses with hydrogen. There are various schemes, but they all suffer from the problem that hydrogen is difficult stuff to store or transport. It’s not easily liquefied, and the tiny size of its molecule means that many containment materials that are fine for methane simply won’t hold on to it.

[Isographer] has an idea: to transport the energy not as hydrogen but as metallic aluminium, and generate hydrogen by reaction with aqueous sodium hydroxide. He’s demonstrated it by generating enough hydrogen to make a cup of coffee, as you can see in the video below the break.

It’s obviously very successful, but how does it stack up from a green perspective? The feedstocks are aluminium and sodium hydroxide, and aside from the hydrogen it produces sodium aluminate. Aluminium is produced by electrolysis of molten bauxite and uses vast amounts of energy to produce, but since it is often most economic to do so using hydroelectric power then it can be a zero-carbon store of energy. Sodium hydroxide is also produced by an electrolytic process, this time using brine as the feedstock, so it also has the potential to be produced with low-carbon electricity. Meanwhile the sodium aluminate solution is a cisutic base, but one that readily degrades to inert aluminium oxide and hydroxide in the environment. So while it can’t be guaranteed that the feedstock he’s using is low-carbon, it’s certainly a possibility.

So given scrap aluminium and an assortment of jars it’s possible to make a cup of hot coffee. It’s pretty obvious that this technology won’t be used in the home in this way, but does that make it useless? It’s not difficult to imagine energy being transported over distances as heavy-but-harmless aluminium metal, and we’re already seeing a different chemistry with the same goal being used to power vehicles.

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Can We Repurpose Old Wind Turbine Blades?

October 8, 2021 by Lewin Day 92 Comments

Wind turbines are a fantastic, cheap, renewable source of energy. However, nothing lasts forever, and over time, the blades of wind turbines fatigue and must be replaced. This then raises the question of what to do with these giant waste blades. Thankfully, a variety of projects are exploring just those possibilities.

A Difficult Recycling Problem

Around 85% of a modern wind turbine is recyclable. The problem is that wind turbine blades currently aren’t. The blades last around 20 to 25 years, and are typically made of fiberglass or carbon fiber. Consisting of high-strength fibers set in a resin matrix, these composite materials are incredibly difficult to recycle, as we’ve discussed previously. Unlike metals or plastics, they can’t just be melted down to be recast as fresh material. Couple this with the fact that wind turbine blades are huge, often spanning up to 300 feet long, and the problem gets harder. They’re difficult and expensive to transport and tough to chop up as well.

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Researchers monitor calves as they use the MooLoo, a special pen for urination.

Toilet-Training Cows Is No Bull

September 21, 2021 by Kristina Panos 28 Comments

Human activity may be the main cause of climate change, but all these cows milling and mooing about don’t help, either. Everyone knows that cows produce methane-laden flatulence, but there’s another problem — their urine contains ammonia. The nitrogen leeches into the soil and turns into nitrous oxide, which is no laughing matter. So what’s the answer, giant diapers? No, just train them to use a toilet instead of the soil-let.

A pair of researchers from the University of Auckland traveled to a research institute’s farm in Germany with the hope of training a group of 16 calves to do their business in a special pen. The “MooLoo” is painted bright green and carpeted with artificial turf so it’s less weird for the cows. First they left the calves in the pen until they peed, and then gave it a reward of sugar water. From there, they started extended the animals’ distance from the MooLoo. Whenever the calves thought outside the box, they would be sprayed with water for three seconds. The results are kind of surprising: within an average of 15-20 urination sessions, 11 of the 16 cows had been trained successfully and were using the MooLoo 75% of the time. Watch a calf earn some sugar water after the break.

German cows mostly live in barns, but millions of other cows spend much of their time outside. So, how would that work? The researchers believe that cows could be trained to go when they gather for milking time. Makes sense to us, but how do you train cows on a large scale? Maybe with bovine VR?

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The World’s First Autonomous Electric Cargo Ship Is Due To Set Sail

September 14, 2021 by Lewin Day 55 Comments

Maritime shipping is big business, with gigantic container ships responsible for moving the vast majority of the world’s goods from point A to points B, C and D. Of course, there’s a significant environmental impact from all this activity, something ill befitting the cleaner, cooler world we hope the future will be. Thus, alternatives to the fossil fuel burning ships of old must be found. To that end, Norwegian company Yara International has developed a zero-emission ship by the name of Yara Birkeland, which aims to show the way forward into a world of electric, autonomous sea transport.

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Arduino Powered Heat Pump Controller Helps Warm Your Toes

September 8, 2021 by Dave Rowntree 39 Comments

Heat pump heating technology is starting to pop up more and more lately, as the technology becomes cheaper and public awareness and acceptance improves. Touted as a greener residential heating system, they are rapidly gaining popularity, at least in part due to various government green policies and tax breaks.

[Gonzho] has been busy the last few years working on his own Arduino Powered Open Source heat pump controller, and the project logs show some nice details of what it takes to start experimenting with heat pumps in general, if that’s your game. Or you could use this to give an old system a new lease of life with an Arduino brain transplant.

In essence they are very simple devices; some kind of refrigerant is passed through a source of heat, absorbing some of it, it then flows elsewhere, and is compressed, which increases its temperature, before that increased heat is lost where the increase in temperature is desired.

This heat source could be a river, a mass of pipes buried in the ground, or simply the air around you. The source and quality of the heat source as well as the desired system operating temperature dictate the overall efficiency, and with ground-source systems it’s even possible to dump excess heat directly into the ground and store it for when required later. This could be the result of a residential cooling system, or even directly sourced from a solar heated setup.

This heat pumping process is reversible, so it is possible to swap the hot and cold ends, just by flipping some valves, and turn your space heater into a space cooler. This whole process can trace its roots back to the super talented Scottish professor, William Cullen who in 1748 was the first person on record to demonstrate artificial refrigeration.

The power needed to run the compressor pump and control gear is usually electrically derived, at least in non-vehicular applications, but the total power required is significantly less than the effective heating (or cooling) power that results.

We’ve covered a few heat pump hacks before, like this guy who’s been heating his house geothermally for years, but not so many platforms designed for experimentation from the ground up.

The associated GitHub project provides the gerber files as well as the Arduino code, so you’ve got a great starting point for your own heat pumping builds.

EBike Conversion On A Budget Uses Skateboard Motor

August 28, 2021 by Mike Szczys 30 Comments

[Dave Schneider] has been chasing an electric-bike build for more than 10 years now. When he first started looking into it back in 2009, the cost was prohibitive. But think of how far we’ve come with the availability of motors, electronic speed controllers, and of course battery technology. When revisiting the project this year, he was able to convert a traditional bicycle to electric-drive for around $200.

Outrunner motor drives rear wheel via friction

Electric skateboards paved the way for this hack, as it was an outrunner motor that he chose to use as a friction drive for the rear wheel. The mounting brackets he fabricated clamp onto the chain stay tubes and press the body of the motor against the tire.

The speed of the motor is controlled by a rocker switch on the handlebars, but it’s the sensors in the brake levers that are the neat part. Magnets added to each brake lever are monitored by hall-effect sensors so that the throttle cuts whenever it senses the rider squeezing the front brake (effectively free-wheeling the bike), while the rear brake triggers a regenerative braking function he’s built into the system!

Sure you can buy these bikes, you can even buy conversion kits, but it’s pretty hard to beat the $88 [Dave] spent on the motor when the cost of purpose-built motors is usually several times this figure. The rest is fairly straight-forward, and besides ordering batteries and an electronic speed controller, you likely have the bits you need just waiting for you in your parts bin.

Occam’s Razor: Gardening Edition

August 21, 2021 by Bryan Cockfield 44 Comments

While the impulse to solving problems in complex systems is often to grab a microcontroller and some sensors to automate the problem away, interfacing with the real world is often a lot more difficult than it appears. Measuring soil moisture, for example, seems like it would be an easy way of ensuring plants get the proper amount of water, but soil is a challenging environment for electronics and this solution often causes more problems than it solves. [Kevin] noticed this problem with soil moisture sensors and set about solving this problem with a much simpler, though indirect, method of monitoring his plants electronically.

Rather than relying on soil conductivity for testing soil moisture levels, he has developed an alternate method of determining if the plants need to be watered simply by continuously weighing them. The hypothesis that he had was that a plant that needs water will weigh less as the available water respirates out of the plant or evaporates from the soil. This means that using a reliable sensor like a load cell to measure weight rather than an unreliable one like a soil moisture sensor will result in more reliable data he can use to automate his plants’ watering.

[Kevin]’s build is based around an ESP32 and a commercially-available load cell which are all built into the base of the plant’s pot. The design hides all of the electronics in a pleasant enclosure and is able to communicate relevant info wirelessly as well. The real story here, however, isn’t a novel use of an ESP32 chip, but rather out-of-the-box problem solving by using an atypical sensor to solve this problem. That’s not to say that you can’t ever use other sensors to directly monitor your garden and automate its health, though.