An image of an orange, translucent glowing quartz rod. Thermocouples can be seen at intervals along the rod looking in.

Industrial Solar Heat Hits 1000˚C

While electricity generation has been the star of the energy transition show, about half of the world’s energy consumption is to make heat. Many industrial processes rely on fossil fuels to reach high temps right now, but researchers at ETH Zurich have found a new way to crank up the heat with a solar thermal trap. [via SciTechDaily]

Heating water for showers or radiant floor systems in homes is old hat now, but industrial application of solar power has been few and far between. Part of the issue has been achieving high enough temperatures. Opaque absorbers can only ever get as hot as the incident surface where the sun hits them, but some translucent materials, like quartz can form thermal traps.

In a thermal trap, “it is possible to achieve temperatures that are higher in the bulk of the material than at the surface exposed to solar radiation.” In the study, the researchers were able to get a 450˚C surface to produce 1,050˚C interior temperature in the 300 mm long quartz rod. The system does rely on concentrated solar power, 135 suns-worth for this study, but mirror and lens systems for solar concentration already exist due to the aforementioned electrical power generation.

This isn’t the only time we’ve seen someone smelting on sunlight alone, and you can always do it less directly by using a hydrogen intermediary. If you’re wanting a more domestic-level of heat, why not try the wind if the sun doesn’t shine much in your neighborhood?

DIY Bimetallic Strip Dings For Teatime

Do you like your cup of tea to be cooled down to exactly 54 C, have a love for machining, and possess more than a little bit of a mad inventor bent? If so, then you have a lot in common with [Chronova Engineering]. In this video, we see him making a fully mechanical chime-ringing tea-temperature indicator – something we’d be tempted to do in silicon, but that’s admittedly pedestrian in comparison.

The (long) video starts off with making a DIY bimetallic strip out of titanium and brass, which it pretty fun. After some math, it is tested in a cup of hot water to ballpark the deflection. Fast-forward through twenty minutes of machining, and you get to the reveal: a tippy cup that drops a bearing onto a bell when the deflection backs off enough to indicate that the set temperature has been reached. Rube Goldberg would have been proud.

OK, so this is bonkers enough. But would you believe a bimetallic strip can be used as a voltage regulator? How many other wacky uses for this niche tech do you know?

Thanks [Itay] for the tip!

A small gauge showing power generated by a house's solar panels.

Cute Solar Power Gauge Brightens The Day

What’s the first thing you want after installing solar? All the sunshine you can get, of course. Especially if you did it in the wintertime. And what would be more fun than monitoring your power generation, especially leading up to the equinox, or start of spring? Probably not much, especially if you built a cute solar power gauge like [Ben] did to keep him from obsessively checking his phone.

At the heart of this build is the affordable Seeed Xiao ESP32C3, which controls an equally cost-effective automotive stepper via an L293D H-bridge driver. Then it was just a matter of hooking it into Home Assistant. As power is generated by the solar system, the cute little sun on the gauge rises and shows the kilowattage gained.

Unfortunately there’s no real data sheet for the stepper, so [Ben] opted to use the 5 V from the USB that’s powering the ESP32. However, it seems like this might not be enough power because the gauge appears to drift a bit. To fix this, [Ben] runs the stepper_init script twice a day, which cranks the dials all the way forward then all the way backward before settling on the last known value.

Are you interested in solar? Here’s how you can build a small power system.

Bad Experiences With A Cheap Wind Turbine

If you’ve got a property with some outdoor space and plenty of wind, you might consider throwing up a windmill to generate some electricity. Indeed, [The Broject List] did just that. Only, his experience was a negative one, having purchased a cheap windmill online. He’s warning off others from suffering the same way by explaining what was so bad about the product he bought.

The windmill in question was described as a “VEVOR Windturbine”, which set him back around 100 euros, and claimed to be capable of producing 600 watts at 12 volts. He starts by showing how similar turbines pop up for sale all over the Internet, with wildly inflated specs that have no relation to reality. Some sellers even charge over 500 euros for the same basic device.

He then demonstrates the turbine operating at wind speeds of approximately 50 km/h. The output is dismal, a finding also shared by a number of other YouTube channels out there. Examining the construction of the wind turbine’s actual generator, he determines that it’s nowhere near capable of generating 600 watts. He notes the poorly-manufactured rotor and aluminium coils as particular disappointments. He concludes it could maybe generate 5 watts at most.

Sadly, it’s easy to fall into this trap when buying online. That’s where it pays to do your research before laying down your hard-earned cash. Continue reading “Bad Experiences With A Cheap Wind Turbine”

Giant Sails Actually Help Cargo Ships Save Fuel, And The Planet In Turn

Shipping is not a clean business. The global economy is fueled by trade, and much of that trade involves hauling product from point A to point B. A great deal of that product goes by water. Shipping it around uses a great deal of fuel, and creates a great deal of greenhouse gas emissions. It’s bad for the environment, and it’s costly for shipping companies.

Any gain in efficiency can be an edge in this regard, and beneficial for the planet to boot. Now, it appears that good old fashioned sails  might just be the tool that companies need to clean up their fleets. And it’s not some theory—real world numbers back it up!

Where The Wind Takes You

Sea transport has been branded as a significant contributor to global greenhouse gas emissions, accounting for about 3% of the total. Shipping companies in turn are under increasing pressure to innovate and adapt, both for the good of the planet and their own coffers. It’s perhaps a small blessing that saving fuel and slashing emissions go hand in hand, and companies are desperate for any technology that can deliver on those goals.

Enter the WindWings, a revolutionary “wind assisted propulsion” concept developed by BAR Technologies. In partnership with ocean freight firm Cargill, these radical sails were installed aboard the Pyxis Ocean, a Kamsarmax bulk carrier chartered from Mitsubishi. These aren’t the canvas and rope constructs of yore . Instead, they’re a set of towering metal sails that stand 123 feet tall, designed to harness the wind’s power and propel the massive bulk carrier across the oceans. Continue reading “Giant Sails Actually Help Cargo Ships Save Fuel, And The Planet In Turn”

five 100% recycled keycaps, spaced out

These Keycaps Are 100% Recycled Plastic

Artisan keycaps are generally meant to replace your Escape key, though they can be used anywhere you like (as long as they fit, of course). Keycap maker [tellybelly] of jankycaps has been experimenting with making keycaps out of 100% recycled plastic, and offers an interesting post detailing their development and production process.

Animation of injection molding flow into a set of four keycaps.What do you do when normal injection molding tooling is out of your budget, and silicone molds simply won’t do? You turn to 3D printing if you can. In this case, [tellybelly] and company found a resin designed to withstand high temperatures.

[tellybelly] was able to design the mold using a plethora of online resources, and even verified the flow using a special program. Although the first two versions worked, they had some flaws. Third time’s the charm, though, and then it was time to sort plastic and fire up the shredder.

After heating up the shreds to 200 °C or so, it was time to start the injecting. This part isn’t exactly a cakewalk — mixing different plastics together can vary the workable temperature range that doesn’t degrade the plastic. Although it sounds like the end, [tellybelly] reports that they spent just as much time here as they did at the drawing board, experimenting with pressure on the mold, various cool-down methods, and how long to wait before opening the mold.

Via reddit

A Smarter Solar Water Heater

Installing solar power at a home is a great way to reduce electricity bills, especially as the cost of solar panels and their associated electronics continue to plummet. Not every utility allows selling solar back to the grid, though, so if you’re like [Rogan] who lives in South Africa you’ll need to come up with some clever tricks to use the solar energy each day while it’s available to keep from wasting any. He’s devised this system for his water heater that takes care of some of this excess incoming energy.

A normal water heater, at least one based on electric resistive heaters, attempts to maintain a small range of temperatures within the insulated tank. If the temperature drops due to use or loss to the environment, the heaters turn on to bring the temperature back up. This automation system does essentially the same thing, but allows a much wider range of temperatures depending on the time of day. Essentially, it allows the water heater to get much hotter during times when solar energy is available, and lets it drop to lower values before running the heater on utility electricity during times when it isn’t. Using a combination ESP32 and ATtiny to both control the heater and report its temperature, all that’s left is to program Home Assistant to get the new system to interact with the solar system’s battery charge state and available incoming solar energy.

While it’s an elegantly simple system that also affords ample hot water for morning showers, large efficiency gains like this can be low-hanging fruit to even more home energy savings than solar alone provides on paper. Effectively the water heater becomes another type of battery in [Rogan]’s home, capable of storing energy at least for the day in the form of hot water. There are a few other ways of storing excess renewable energy as well, although they might require more resources than are typically available at home.