We have no idea whether [Nick Goodey] is a trained engineer or not. But given the detailed design of this DIY energy recovery ventilator for his home HVAC system, we’re going to go out on a limb and say he probably knows what he’s doing.
For those not in the know, an energy recovery ventilator (ERV) is an increasingly common piece of equipment in modern residential and commercial construction. As buildings have become progressively “tighter” to decrease heating and cooling energy losses to the environment, the air inside them has gotten increasingly stale. ERVs solve the problem by bringing fresh, unconditioned air in from the outside while venting stale but conditioned air to the outside. The two streams pass each other in a heat exchanger so that much of the energy put into the conditioned air is transferred to the incoming unconditioned air.
While ERV systems are readily available commercially, [Nick] decided to roll his own after a few experiments with Coroplast and some extensive calculations convinced him it would be a viable idea. One may scoff at the idea of corrugated plastic for the heat exchanger, but the smooth channels through the material make it a great choice. He built up a block of Coroplast squares with the channels in alternate layers oriented orthogonally, letting stale inside air pass very close to fresh outside air to exchange heat without ever mixing directly. The entire system, including fans, an Arduino for control, sensors galore, and the Hubitat home automation hub, is powered by DC, so no electrician was needed. [Nick] has a ton of detail in his build log, including all the tools and calculators he used to design the system.
Given the expense of ERV systems, we’re surprised we haven’t seen more stories about DIY versions. We have talked about HVAC systems a lot, though — after all, HVAC techs are hackers who make housecalls.
There’s a laundry list of ways that humans are polluting the earth, and even though it might not look like it from the surface, the oceans seem to bear the brunt of our waste. Some research suggests that plastic doesn’t fully degrade as it ages, but instead breaks down into smaller and smaller bits that will be somewhere the in environment for such a long time it could be characterized in layman’s terms as forever.
Not only does waste of all kinds make its way to the oceans by rivers or simply by outright dumping, but commercial fishing gear is estimated to comprise around 10% of the waste in the great blue seas, and one of the four nonprofits help guide this year’s Hackaday Prize is looking to eliminate some of that waste and ensure it doesn’t cause other problems for marine life. This was the challenge for the Conservation X Labs dream team, three people who were each awarded a $6,000 micro-grant to work full time for two months on the problem.
It isn’t about simply collecting waste in the ocean, but rather about limiting the time that potentially harmful but necessary fishing equipment is in the water in the first place. For this two-month challenge, this team focused on long lines used by professional fishing operations to attach buoys to gear like lobster pots or crab traps. These ropes are a danger to large ocean animals such as whales when they get tangled in them and, if the lines detach from the traps, the traps themselves continue to trap and kill marine life for as long as they are lost underwater. This “ghost gear” is harmful in many different ways, and reducing its time in the water or “soak time” was the goal for the project.
Let’s take a closer look at their work after the break, and we can also see the video report they filed as the project wrapped up.
In America, corn syrup is king, and real sugar hovers somewhere around prince status. We’re addicted to corn, and corn, in turn, is addicted to nitrogen. A long time ago, people figured out that by rotating crops, the soil will stay nutrient-rich, which helps to an extent by retaining nitrogen. Then we figured out how to make nitrogen fertilizer, and through its use we essentially doubled the average crop yield over the last hundred years or so.
The aerial roots of the Sierra Mixe corn stalk help the plant produce its own nitrogen. Image via Wikimedia Commons
Not all plants need extra nitrogen. Legumes like beans and soybeans are able to make their own. But corn definitely needs nitrogen. In the 1980s, the now-chief of agriculture for Mars, Inc. Howard-Yana Shapiro went to Mexico, corn capital of the world, looking for new kinds of corn. He found one in southern Mexico, in the Mixes District of Oaxaca. Not only was this corn taller than American corn by several feet, it somehow grew to these dizzying heights in terrible soil.
So if we already have nitrogen fertilizer, why even look for plants that do it themselves? The Haber-Bosch fertilizer-making process, which is an artificial form of nitrogen fixation, does make barren soil less of a factor. But that extra nitrogen in ammonia-based fertilizer tends to run off into nearby streams and lakes, making its use an environmental hazard. And the process of creating ammonia for fertilizer involves fossil fuels, uses a lot of energy, and produces greenhouse gases to boot. All in all, it’s a horrible thing to do to the environment for the sake of agriculture. But with so many people to feed, what else is there to do?
Over the last decade, the UC Davis researchers use DNA sequencing to determine that the mucus on the Sierra Mixe variety of the plant provides microbes to the corn, which give it both sugars to eat and a layer of protection from oxygen. They believe that the plants get 30-80% of their nitrogen this way. The researchers also proved that the microbes do in fact belong to nitrogen-fixing families and are similar to those found in legumes. Most impressively, they were able to transplant Sierra Mixe corn to both Davis, California and Madison, Wisconsin, and have it grow successfully, proving that the nitrogen-fixing trick isn’t limited to the corn’s home turf. Now they are working to identify the genes that produce the aerial roots.
One Step in a Longer Journey of Progress
We probably won’t be switching over to Sierra Mixe corn anytime soon, however. It takes eight months to mature, which is much too slow for American appetites used to a three-month maturation period. If we can figure out how to make other plants do their own nitrogen fixation, who knows how far we could go? It seems likely that more people would accept a superpower grafted from a corn cousin instead of trying to use CRISPR to grant self-nitrogen fixation, as studies have shown a distrust of genetically modified foods.
The issue of intellectual property rights could be a problem, but the researchers started on the right foot with the Mexican government by putting legal agreements in place that ensure the Sierra Mixe community benefits from research and possible commercialization. We can’t wait to see what they’re able to do. If they’re unable to transplant the power of self-fixation to other plants, then perhaps there’s hope for improving the Haber-Bosch process.
It’s really beginning to feel as though the problem of climate change is a huge boulder rolling down a steep hill, and we have the Sisyphean task of trying to reverse it. While we definitely need to switch as much of the planet over to clean, green energy as soon as possible, the deployment should be strategic. You know, solar panels in sunny places, and wind turbines in windy places. And for the most part, we’re already doing that.
A test unit in Okinawa, Japan. Image via Challenergy
In the meantime, there are also natural disasters to deal with, some of which are worsened by climate change. Eastern and Southeast Asian countries are frequently under the threat of typhoons that bring strong, turbulent winds with them. Once the storms pass, they leave large swaths of lengthy power outages in their wake.
Studies have shown that these storms are gaining strength over the years, leading to more frequent disruption of existing power systems in those areas. Wind power is the ideal solution where storms have come through and knocked out traditional power delivery all over a region. As long as the turbines themselves can stand up to the challenge, they can be used to power micro-grids when other delivery is knocked out.
Bring On the Typhoons?
Unfortunately, the conventional three-bladed wind turbines you see dotting the plains can’t stand up to the awesome power of typhoons. But vertical axis wind turbines can. Though they have been around for many years, they may have finally found their niche.
Science fiction movies often portray horticulture in the future, be it terrestrial or aboard spacecraft, with hydroponic gardens overflowing with leafy greens and brightly colored fruit. There is no soil, just clear water that hints at future-people creating a utopia of plant strains untethered from their earthly roots.
This star-faring food production method is not fiction if you forego the polycarbonate tubing, neon accent lights, and gardening robots. For his 2020 Hackaday Prize entry, [AVR] shares how he creates a bed for sixteen plants with parts sourced at a nearby home-improvement store. It may lack the visual pizzaz of the Hollywood versions, but it will grow soil-less crops on a hacker budget.
The starting point for this build is a sturdy wooden base. The PVC tubing and fence parts on top are light, but the water inside them will get heavy, and if you grow large plants, they become surprisingly heavy. Speaking of water, the sub-category of hydroponics this falls under is Nutrient Film Technique, or NFT, which uses a shallow stream of water laden with all the nutrients for plant growth. The square fence posts provide a flat top for mounting mesh cups where the plants grow and a flat bottom where the stream continuously flows. A basin and pump keep the plants refreshed and fed until they are ready for harvest.
Telsa are one of the world’s biggest purchasers of batteries through their partnerships with manufacturers like Panasonic, LG and CATL. Their endless hunger for more cells is unlikely to be satiated anytime soon, as demand for electric cars and power storage continues to rise.
As announced at their Battery Day keynote, Tesla has been working hard on a broad spectrum of projects to take battery technology to the next level in order to reach their goal of 3 TWh annual production by 2030. One of the most interesting aspects of this was the announcement of Tesla’s new tabless 4680 battery, which will be manufactured by the company itself. Let’s take a look at what makes the 4680 so exciting, and why going tabless is such a big deal. Continue reading “Tesla’s New Tabless Batteries Unlock New Levels Of Performance”→
Since the widespread manufacture of plastics began in earnest in the early 1950s, plastic pollution in the environment has become a major global problem. Nowhere is this more evident than the Great Pacific Garbage Patch. A large ocean gyre that has become a swirling vortex full of slowly decaying plastic trash, it has become a primary target for ocean cleanup campaigns in recent years.
However, plastic just doesn’t magically appear in the middle of the ocean by magic. The vast majority of plastic in the ocean first passes through river systems around the globe. Thanks to new research, efforts are now beginning to turn to tackling the issue of plastic pollution before it gets out to the broader ocean, where it can be even harder to clean up. Continue reading “Targeting Rivers To Keep Plastic Pollution Out Of The Ocean”→
