green hacks

771 Articles

Increasing PV Solar Cell Efficiency Through Cooling

January 14, 2023 by 54 Comments

An unavoidable aspect of photovoltaic (PV) solar panels is that they become less efficient when they warm up. [Tech Ingredients] explains in a new video the basic reason for this, which involves the input of thermal energy affecting the semiconductor material. In the subsequent experiment, it is demonstrated how cooling the backside of the panel affects the panel’s power output.

There are commercial solutions that use water cooling on the back of panels to draw heat away from panels, but this still leaves the issues of maintenance (including winter-proofing) and dumping the heat somewhere. One conceivable solution for the latter is to use this heat for a household’s hot water needs. In the demonstrated system a heatsink is installed on the back of the panel, with fans passing cool air over the heatsink fins.

On a 100 Watt PV panel, 10 W was lost from the panel heating up in the sun. After turning on the fans, the panel dropped over 10 °C in temperature, while regaining 5.5 W. Since the installed fans consumed about 3 W, this means that the fans cost no extra power but resulted in increased production. Not only that, but the lower temperatures will in theory extend the panel’s lifetime. Though even with active cooling, even the best of PV panels will need to be replaced after a couple decades.

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A blue enclosure with "IoT AI-assisted Deep Algae Bloom Detector w/Blues Wireless" written on the front. Two black cables run over a wooden desk to a cylinder with rocks on the bottom and filled with murky water. A bookshelf lurks in the background.

Detecting Algal Blooms With The Help Of AI

January 13, 2023 by 1 Comment

Harmful Algal Blooms (HABs) can have negative consequences for both marine life and human health, so it can be helpful to have early warning of when they’re on the way. Algal blooms deep below the surface can be especially difficult to detect, which is why [kutluhan_aktar] built an AI-assisted algal bloom detector.

After taking images of deep algal blooms with a boroscope, [kutluhan_aktar] trained a machine learning algorithm on them so a Raspberry Pi 4 could recognize future occurrences. For additional water quality information, the device also has an Arduino Nano connected to pH, TDS (total dissolved solids), and water temperature sensors which then are fed to the Pi via a serial connection. Once a potential bloom is spotted, the user can be notified via WhatsApp and appropriate measures taken.

If you’re looking for more environmental sensing hacks, check out the OpenCTD, this swarm of autonomous boats, or this drone buoy riding the Gulf Stream.

3D Printed Wind Turbine Has All The Features, Just Smaller

January 11, 2023 by 32 Comments

For anyone with even the slightest bit of engineering interest, wind turbines are hard to resist. Everything about them is just so awesome, in the literal sense of the word — the size of the blades, the height of the towers, the mechanical guts that keep them pointed into the wind. And as if one turbine isn’t enough, consider the engineering implications of planting a couple of hundred of these giants in a field and getting them to operate as a unit. Simply amazing.

Unfortunately, the thing that makes wind turbines so cool — their enormity — can make them difficult to wrap your head around. To fix that, [3DprintedLife] built a working miniature wind turbine that goes a bit beyond most designs of a similar size. The big difference here is variable pitch blades, a feature the big turbines rely on to keep their output maximized over a broad range of wind conditions. The mechanism here is clever — the base of each blade rides in a bearing and has a small cap head screw that rides in a hole in a triangular swash block in the center of the hub. A small gear motor and lead screw move the block back and forth along the hub’s axis, which changes the collective pitch of the blades.

Other details of full-sized wind turbines are replicated here too, like the powered nacelle rotation and the full suite of wind speed and direction sensors. The generator is a NEMA 17 stepper; the output is a bit too anemic to actually power the turbine’s controller, but that could be fixed with gearing changes. Still, all the controls worked as planned, and there’s room for improvement, so we’ll score this a win overall.

Looking for a little more on full-size wind turbines? You’re in luck — our own [Bryan Cockfield] shared his insights into how wind farm engineers deal with ice and cold.

Continue reading “3D Printed Wind Turbine Has All The Features, Just Smaller” →

The Dawn Of Synthetic Milk: When Milk Becomes More Like Beer

January 5, 2023 by 85 Comments

What would we do without milk in modern day society? Although lactation originally evolved as a way to provide a newborn mammal with nutrients and the other essentials during the first weeks of their life, milk has for thousands of years now been a staple food in human cultures. Whether from cows, camels, sheep or other mammals, each year humans consume many liters of this mythical substance, with our galaxy’s name – the Milky Way –  coming courtesy of Greek mythology and a spilled milk incident.

A major issue with mammalian milk, however, is that it is only produced by females for a certain time after giving birth, which requires for example a dairy cow to constantly go through pregnancies, which is both cumbersome and not very animal-friendly. Simultaneously, the newborn offspring cannot drink this milk, but must be provided with an alternative. For these reasons synthetic milk is becoming an increasingly more popular animal- and environmentally-friendly alternative.

For years now, companies such as US-based Perfect Day are producing milk that’s for all intents and purposes identical to cow milk, with the added advantage of being free of lactose and other problematic additions. The best part of this all? It’s all done with existing fermentation techniques.

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If You Can’t See A Solar Panel, That Doesn’t Mean It’s Not There

December 31, 2022 by 45 Comments

In the shift away from fossil fuel energy sources, there has been a huge expansion in solar power. We’ve seen solar thermal plants in the desert and photovoltaic panel farms covering huge areas of land, but perhaps the most potential comes from placing the panels on rooftops. In some parts of the world this is encouraged through a system of subsidies, as is the case in Italy. But what if your building is part of a protected world heritage site such as the Roman city of Pompeii? The answer comes in the form of traditional roof tiles that hide their photovoltaic elements under a polymer skin that looks for all the world like a traditional Roman pan tile. As is so often the case with such products, the manufacturer’s description page is cagey about the details in the name of protecting their invention. What they do tell us is that the tile uses conventional solar cells mounted underneath the polymer layer, which is described as “opaque at the sight but translucent to sun rays“. This sounds like an inherent contradiction, so naturally, we’re intrigued as to how it works. Continue reading “If You Can’t See A Solar Panel, That Doesn’t Mean It’s Not There” →

Australia’s Soft Plastic Recycling Debacle

December 15, 2022 by 81 Comments

We’ve all been told to cut back on waste to help prevent environmental crisis on Earth. Reducing waste helps reduce the need to spend time and energy digging up fresh materials, and helps reduce the amount of trash we have to go out and bury in the ground in landfills. Recycling is a big part of this drive, allowing us to divert waste by reprocessing it into fresh new materials.

Sadly, though, recycling isn’t always as magical as it seems. As Australia has just found out, it’s harder than it sounds, and often smoke and mirrors prevent the public from understanding what’s really going on. Here’s how soft plastic recycling went wrong Down Under.

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Singapore Branches Out Into Internet Of Trees

December 8, 2022 by 18 Comments

Five years ago, a 38-year-old woman was enjoying an outdoor concert with her family with one of her twin infants in her arms. In the week prior, it had been windy and rainy, but today, the weather was nice, and the concert was crowded. Without warning, a 270-year-old tembusu tree fell on the woman, pinning and ultimately killing her after the other concertgoers couldn’t remove it in time. This tragedy happened in spite of twice-yearly inspections where the tree showed no visual signs of trouble.

It’s exactly this type of incident that Singaporean officials hope to avoid by building an Internet of Trees. The equatorial island nation is home to roughly 5.5 million people, and around 7 million trees — about 6 million of which are tracked by Singapore’s National Parks Board, so that they can be managed remotely with an app. (The Board only tracks trees once they’ve reached a certain size, so we’ll assume that the other million are too young to join the fun just yet.)

While tree-triggered deaths are fairly few and far between, there are plenty of other ‘tree incidents’ that can occur, such as a branch falling, or a tree trunk snapping or uprooting. Depending on the size of the branch, this can be a dangerous nuisance as it could block roads, obscure signage, or destroy property. Thanks to the efforts of the National Parks Board, these incidents have dropped from around 3,000 per year at the turn of the millennium to under 500 per year today.

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