efficiency

28 Articles

It’s Opposite Day For This Novel Wankel Engine

April 14, 2023 by 28 Comments

The Wankel engine seems to pop up in surprising places every so often, only to disappear into the ether before someone ultimately resurrects it for a new application and swears to get it right this time. Ultimately they come across the same problems that other Wankels suffered from, namely poor fuel efficiency and issues with reliability. They do have a surprising power-to-weight ratio and a low parts count, though, which is why people keep returning to this well, although this time it seems like most of the problems might have been solved simply by turning the entire design inside out.

A traditional Wankel engine has a triangular-shaped rotor that rotates around a central shaft inside an oval-shaped housing. This creates three chambers which continually revolve around inside the engine as the rotor spins. The seals that separate the chambers are notoriously difficult to lubricate and maintain. Instead of using a rotor inside of a chamber, this design called the X-Engine essentially uses a chamber inside of a rotor, meaning that the combustion chamber and the seals stay in fixed locations instead of spinning around. This allows for much better lubrication of the engine and also much higher efficiency. By flipping the design on its head it is able to maintain a low moving parts count, high compression ratio, and small power-to-weight ratio all while improving reliability and performance and adding the ability to directly inject fuel rather than rely on carburetion or other less-ideal methods of fuel delivery that other Wankels require.

Astute internal combustion aficionados will note that this engine is still of a two-stroke design, and thus not likely to fully eliminate the emissions problems with Wankels in a way that is satisfactory to regulators of passenger vehicles. Instead, the company is focusing on military, commercial, and aerospace applications where weight is a key driver of design. We’ve seen time and time again how the Wankel fails to live up to its promises though, and we hope that finally someone has cracked the code on one that solves its key issues.

A Single-Watt Hydroponic Lighting System

October 31, 2022 by 24 Comments

Hydroponic systems are an increasingly popular way to grow plants indoors using a minimum of resources. Even some commercial farming operations are coming online using hydroponic growing techniques, as these methods consume much less water, land area, and other resources than traditional agricultural methods. The downside is that the required lighting systems often take an incredible amount of energy. That’s why [ColdDayApril] set up a challenge to grow a plant hydroponically using no more than a single watt.

The system is set up to grow a single pepper plant in what is known as a deep-water culture, where the plant is suspended in a nutrient solution which has everything it needs to grow. The lightning system is based around the Samsung LM301B which comes close to the physical limits for converting electricity into white light and can manage around 220 lumens. A special power supply is needed for these low-power diodes, and the light is efficiently directed towards the plant using a purpose-built reflective housing. By placing this assembly very close to the plant and adjusting it as it grows, [ColdDayApril] was able to take the pepper plant from seed to flowering in 92 days.

It’s worth noting that the rest of the system uses a little bit of energy too. A two watt fan helps circulate some air in the hydroponic enclosure, and deep-water systems usually require an air pump to oxygenate the water which uses another two watts. This is still an impressive accomplishment as most hobbyist builds use lighting systems rated in the hundreds of watts and use orders of magnitude more energy. But, if you’re willing to add some fish into the system you can mitigate some of the energy requirements needed for managing the water system even further.

A Simple Stove, Built For Beans

October 14, 2022 by 17 Comments

Sitting around a campfire or fireplace is an aesthetically pleasing experience in most situations, and can even provide some warmth. But unless you have a modern wood-burning appliance, it’s likely that most of the energy available in the biomass is escaping as un-burned vapors. Surprisingly, solving this problem is almost as easy as buying a can of beans at the store, and the result is a very efficient stove which can be used for heat in a pinch.

[Robert] is demonstrating this gasifier stove, not with beans but using both a can of peas and a larger can of potatoes. Various holes are drilled in each can in a specific pattern, and then the smaller pea can is fitted inside the larger potato can. Once a fire is going, the holes allow for air to flow in a way which traps the escaping un-burned vapors from the fuel and burns them as they flow through the contraption. No moving parts are required; this is all powered by the natural airflow that’s produced by the heat of the fire.

The result of a build like this is not only a stove which can extract a much higher percentage of the available fuel, but also quires much less fuel for a given amount of heat, and produces a much cleaner, less smokey fire. [Robert] also added a screen mantle which allows for this to be used more as a heat source, but similar builds can also be used just as effectively for cooking, too.

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Winged Drone Gets Forward Flight Capability

October 2, 2022 by 17 Comments

Drones are pretty common in the electoronics landscape today, and are more than just a fun hobby. They’ve enabled a wide array of realtors, YouTubers, surveyors, emergency responders, and other professionals to have an extremely powerful tool at their disposal. One downside to these tools is that the power consumption tends to be quite high. You can either stick larger batteries on them, or, as [Nicholas] demonstrates, just spin them really fast during flight.

We featured his first tests with this multi-modal drone flight style a while back, but here’s a quick summary: by attaching airfoils to the arms of each of the propellers and then spinning the entire drone, the power requirements for level flight can be dramatically reduced. This time, he’s back to demonstrate another benefit to this unique design, which is its ability to turn on its side and fly in level flight like an airplane. It’s a little bizarre to see it in the video, as it looks somewhat like a stationary propeller meandering around the sky, but the power requirements for this mode of flight are also dramatically reduced thanks to those wings on the arms.

There are a few downsides to this design, namely that the vertical wing only adds drag in level flight, so it’s not as efficient as some bi-wing designs, but it compromises for that loss with much more effective hover capabilities. He also plans to demonstrate the use of a camera during spin-hover mode as well in future builds. It’s an impressive experiment pushing the envelope of what a multi-rotor craft can do, and [Nicholas] still has plans to improve the design, especially when it comes to adding better control when it is in spin-hover mode. We’d expect plenty of other drones to pick up some of these efficiency gains too, except for perhaps this one.

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Maximum Power Point Tracking: Optimizing Solar Panels

August 3, 2022 by 59 Comments

When looking at integrating a photovoltaic solar panel into a project, the naive assumption would be that you simply point the panel into the general direction of where the Sun is, and out comes gobs of clean DC power, ready to be used for charging a battery. To a certain extent this assumption is correct, but feeding a solar panel’s output into something like a regular old PWM buck or boost regulator is unlikely to get you anywhere close to the panel’s full specifications.

The keywords here are ‘maximum power point’ (MPP), which refers to the optimal point on the solar panel’s I-V curve. This is a property that’s important not only with photovoltaics, but also with wind turbines and other highly variable power sources. The tracking of this maximum power point is what is generally referred to as ‘MPPT‘, but within this one acronym many different algorithms are covered, each with its own advantages and disadvantages. In this article we’ll take a look at what these MPPT algorithms are, and when you would want to pick a particular one.

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Lawn Mower Carburetor Improves Mileage On Old Sedan

May 16, 2022 by 71 Comments

Before the Ford marketing department started slapping Maverick badges on pickup trucks, the name had been attached to compact cars from the 70s instead. These were cheap even by Ford standards, and were built as a desperate attempt to keep up with Japanese imports that were typically higher quality and more efficient than most American cars at the time. Some people called them the poor man’s Mustang. While Ford and the other American car companies struggled to stay relevant during the gas crisis, it turns out that they could have simply slapped a lawn mower carburetor on their old Mavericks to dramatically improve fuel efficiency.

The old Maverick used a 5 L carbureted V8 engine, which is not exactly the pinnacle of efficiency even by 1970s standards. But [ThunderHead289] figured out that with some clever modifications to the carburetor, he could squeeze out some more efficiency. By using a much smaller carburetor, specifically one from a lawn mower, and 3D printing an adapter for it, he was able to increase the fuel efficiency to over 40 mpg (which is higher than even the modern Mavericks) while still achieving a top speed of 75 mph.

While it’s not the fastest car on the block with this modification, it’s still drives well enough to get around. One thing to watch out for if you try this on your own classic car is that some engines use fuel as a sort of coolant for certain engine parts, which can result in certain problems like burned valves. And, if you don’t have a lawnmower around from which to borrow a carb, take a look at this build which 3D prints one from scratch instead.

Thanks to [Jack] for the tip!

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Custom Controller Ups Heat Pump Efficiency

March 25, 2022 by 59 Comments

Heat Pumps are an extremely efficient way to maintain climate control in a building. Unlike traditional air conditioners, heat pumps can also effectively work in reverse to warm a home in winter as well as cool it in summer; with up to five times the efficiency of energy use as a traditional electric heater. Even with those tremendous gains in performance, there are still some ways to improve on them as [Martin] shows us with some modifications he made to his heat pump system.

This specific heat pump is being employed not for climate control but for water heating, which sees similar improvements in efficiency over a standard water heater. The problem with [Martin]’s was that even then it was simply running much too often. After sleuthing the energy losses and trying a number of things including a one-way valve on the heating water plumbing to prevent siphoning, he eventually found that the heat pump was ramping up to maximum temperature once per day even if the water tank was already hot. By building a custom master controller for the heat pump which includes some timing relays, the heat pump only runs up to its maximum temperature once per week.

While there are some concerns with Legionnaire’s bacteria if the system is not maintained properly, this modification still meets all of Australia’s stringent building code requirements. His build is more of an investigative journey into a more complex piece of machinery, and his efforts net him a max energy usage of around 1 kWh per day which is 50% more efficient than it was when it was first installed. If you’re looking to investigate more into heat pumps, take a look at this DIY Arduino-controlled mini heat pump.

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