In 2015, only 10 percent of America’s energy consumption came from renewable energy sources like wind, solar, and hydropower and less than a quarter of electricity generation came from renewable energy sources, according to the US Energy Information Administration. This represents a significant increase in the last 15 years, but it’s not nearly enough to offset the carbon footprint we’ve created over decades of relying on fossil fuels. In some parts of the developing world, even the consumption of renewable resources like trees has had a significant negative impact on the health of local communities.
At Purdue, engineers, scientists, and entrepreneurs are working to make sustainable and renewable energy a larger part of our lives — here and abroad. At Discovery Park, Purdue’s multi-disciplinary research center, and the Purdue Foundry, which helps Purdue students, professors, and alumni bring their innovative ideas to market, the university is playing a vital role toward creating a sustainable world. Here are six exciting innovations for alternative and sustainable energy that could impact your life in coming decades.
Today, roughly 167,000 piston aircraft fly the North American skies, according to the FAA. These propeller planes are used for firefighting, crop dusting, police surveillance, sporting activities, acrobatics, and business commuting. They are powered by 100LL aviation gas, leaded fuel that is responsible for releasing nearly 500 tons of lead into the atmosphere each year. The environmental and health consequences of this are severe.
“The combustion of leaded avgas in the exhaust becomes ultrafine, invisible toxic dust particulates when it spews into the atmosphere,” says Chris D’Acosta, the CEO of Swift Fuels. “According to published medical research, lead doesn’t dissipate quickly like typical hydrocarbon exhaust in transportation fuels, and it is hazardous to ingest or inhale within the human body. In general, lead does not metabolize in the human body and is described as a probable carcinogen — so long-term exposure can cause serious medical issues.”
This explains why there is now a global action underway, called PAFI, being coordinated by The FAA, EPA, engine makers, airplane makers, international oil companies, fuel distributors, and more to find a solution to replace 100LL with an unleaded fuel.
D’Acosta’s team, which is based at Purdue’s Research Park and collaborates closely with professors in chemical engineering, aviation, and business, has developed an alternative: UL102, an unleaded fuel for high-octane piston aircraft. “It removes highly toxic metal from aviation gas,” says D’Acosta. “The auto and paint industries began removing lead beginning in the 1970s. Oil companies have been working with the FAA to address avgas used in piston aircraft for the past two decades. Then along came Swift.”
D’Acosta says creating a lead-free fuel brings significant challenges, from toxicity to expense, to fuel that’s compatible with aircraft materials that may be decades old. Swift’s fuel is hydrocarbon-based, which is more widely compatible with a diverse piston fleet. The FAA is running safety tests on UL102 through 2018. Once the company receives the FAA stamp of approval, “we expect to be certified to use the fuel in engines and airframes across the US pistonfleet.”
Grissom Controls LLC
Grissom Controls is a Purdue-based startup whose software will help commercial buildings cut their energy use by 30 percent or more. The company was founded by Andrew Martin (CE’14, MS CE’15, MBA’16), who developed his software during his two-year internship with Purdue Physical Facilities.
In large buildings today, heating and cooling systems are highly inefficient. In most cases, the air is heated and cooled in the building’s mechanical rooms and then pumped into offices. “But if the thermostat in a given room is getting too cold,” says Martin, “it will either dump less air or it will heat the air. And if you are cooling the air in the mechanical room and then having to reheat it once it gets to a space, that gets wasteful.”
Martin’s software capitalizes on the wealth of data that utility sensors are constantly generating throughout a building. “I’m plugging into this data stream and then figuring out how that can operate in the cheapest manner possible,” he says. His software takes into account the square footage of the building, and the number of rooms, as well as real-time utility prices. (If electricity is pricey on an especially hot day, for instance, his software will cool the air more but use the fan less.) “It’s designed to be imperceptible,” he says. “Comfort in the building should stay the same.”
Occupants of Mann Hall at Discovery Park didn’t know that Grissom Controls was running a two-week trial last May, despite a 54 percent reduction in the building’s energy use. Martin says in most buildings, a 30 percent energy savings will be more realistic. “But for changing around some software,” he says modestly, “that’s still pretty good.” He needs another six months to a year’s worth of data before he enters the marketplace. “And then once the savings have been proven,” he says, “we can scale pretty quickly.”
“Robotics will be the defining technology of this century,” says Nicolaus Radford, co-Founder and CTO of Houston Mechatronics Inc. “The world of robotics that’s starting to take over — not in the scary way, of course — will be just as pivotal as the Internet or aviation or telecom was in the last century.”
Now, some software to which Radford contributed during his graduate work in electrical engineering at Purdue and funded by both NASA and DARPA, is allowing HMI to make electric cars significantly more efficient. This software, originally applied by HMI toward robotic actuation, is helping make electric cars better as well. HMI works both in the electric vehicle (EV) and robotics markets, and Radford says EVs are starting to look more like robots than not nowadays.
“The software uses evolutionary computing to perform a multi-objective optimization toward electric machine design,” Radford says. In layman’s terms, the software allows cars to go farther, before they run out of juice. “The tech we’ve licensed from Purdue enables us to design motors that have superior efficiency for a given mass,” says Radford. “It allows us to design the most efficient electric machines on the planet.
“There is a new kind of space race in today’s electric cars,” says Radford, “with each manufacturer trying to outdo the other in terms of range and performance. So we’re positioned nicely with our technology advantage.”
The software first was applied in Andretti’s Formula E 200kW racecar, and the resulting motor reached efficiencies above 97% and over 10kW/kg power density, a significant achievement. It then debuted in the Artega Scalo, the first commercially available car to use HMI’s Purdue-based software. The Scalo can go 250 miles before recharging. Its battery can be completely recharged in under an hour. The boutique electric sports car debuted last year at the Frankfurt Motor Show. It has 402hp and 575 lb-ft of torque, which is a tremendous amount of power for a car of this size. The stylish coupe recently went on sale in Europe in a limited run of 12 units for the affordable price of $192,000.
African hybrid systems
Students from Purdue’s Global Engineering Program have created affordable and sustainable hybrid energy solutions to bring electricity to remote African communities. In central Africa, only 5 percent of the population has access to electricity from a governmental power grid. This means families have no lights after dark and no easy way to charge their electronics. In some places, villagers must walk 15 miles or more to charge their cell phones. Further, the heavy dependence on firewood to meet basic energy needs has led to air pollution and deforestation in places like Western Bakossi, Cameroon, a region with roughly 12,000 people. To address these problems, Purdue has partnered with the African Centre for Renewable Energy and Sustainable Technology and Western Bakossi Development to design and implement an off-grid hybrid solar and wind power system to power individual homes.
“In American houses, three or four lights consume 200 watts of electricity,” says Jun Chen, associate professor of mechanical engineering. In rural Cameroon, “our students identified that 200 watts will power a rural household of six people for six hours.” That includes lights for three rooms, two ceiling fans, a cell phone, and a laptop.
The hybrid system is a creative solution to a basic environmental challenge. Chen explains that sub-Saharan Africa has only two seasons: rainy and dry. For six to nine months out of the year, there is no sun. A hybrid system — designed to collect energy from the sun and the wind — enables homes to draw power year round. For the prototype, which students built at Purdue, the solar panel is two square meters and the vertical access turbine is two feet by three feet. The actual apparatus will be slightly larger, “but nothing like the huge turbine blades we have here,” says Chen. The solar panels, batteries, and blades (made from molded sheet metal) can all be locally sourced. “The controller is the only thing we need to purchase from abroad,” says Chen.
There’s a reason why, over the course of a single call, your smartphone might become unexpectedly hot. “When you hold your phone up to your ear, you’re messing with how its antenna receives and transmits information,” says Andrew Kovacs (ECE’05, MS ECE’08, PhD ECE’15), CEO of CommSense, a company based at the Purdue Foundry entrepreneurship and commercialization hub. “Remember the iPhone 4 and how if you held it a certain way, the signal would disappear? Every phone is vulnerable to that problem. Most people don’t know about this, because the phone throws more power to the transmitter to compensate.”
This power suck is what makes the phone hot. But Kovacs has developed a way to keep the signal strong without wasting energy. He’s created a sensor that connects to the phone’s internal antenna. This sensor collects information on how the phone is being manipulated and held and then uses that data to keep the signal strong. “We anticipate 30 percent better battery life,” says Kovacs. “Or a smartphone maker could decide to shrink the battery size to save money.”
This would be great for both consumers and the environment. But Kovacs says phone manufacturers are highly risk-averse. “Saving 30 percent out of nothing — they’d consider that to be crazy,” he says. “You’d have to prove it to them.” Kovacs has demonstrated proof of concept. Getting a sensor into a production smartphone isn’t easy, so he hopes to demonstrate the sensor’s effectiveness in electric cars.
The big thing in that industry right now is wireless charging. “You’d park your car over a flat coil in the ground and that would charge your car overnight or while you’re shopping,” says Kovacs. The problem is that “if you don’t have the vehicle perfectly aligned to the coil, you lose efficiency by as much as 20 or 30 percent.” Kovacs’s sensor may be a solution. It can perceive exactly how the car is positioned and then use that information to compensate for your crappy parking job. “The only other way to do this,” says Kovacs, “is to have an app on the dashboard that directs you to pull ahead three inches or to the left two inches.” But most drivers would find that kind of constant maneuvering incredibly annoying. “People want to park the car and be done with it,” he says. Which is the benefit of the sensor. CommSense’s technology “can tell exactly where the car is in relation to the charger down to millimeter.”
Until recently, electricity and hydrogen have been created independently of each other. But now, through an innovative process called hydricity, Purdue engineers have figured out how to co-produce both, thereby making energy production and storage cleaner and more efficient. This synergetic process “is a breakthrough solution for continuous and efficient power generation,” says Rakesh Agrawal, Winthrop E. Stone Distinguished Professor in the School of Chemical Engineering. The findings were published last December in Proceedings of the National Academy of Sciences and co-authored with Mohit Tawarmalani at the Krannert School of Management.
Hydricity harnesses the sun to create hydrogen by day and then turns those stores into electricity overnight. The process works like this: Solar concentrators (i.e., parabolic troughs that centrally focus sunlight to absorb the most possible energy) trap solar power. This energy then heats water to between 1,000 and 1,400 degrees Celsius. This superheated water then powers steam turbines that can do two things: generate large amounts of electricity and also create stores of hydrogen. These hydrogen stores are then used overnight to superheat more water, thereby creating energy when the sun isn’t shining.
But creating large amounts of hydrogen has more applications than simply generating electricity. “Hydrogen is the building block for chemicals,” says Agrawal. “You can use it to make fertilizer or ammonium nitrate to grow food or all kinds of chemicals.” In other words, the hydrogen created through hydricity has myriad applications beyond the energy sector.
Agrawal’s team is now working to simplify the Hydricity process so that it can be implemented cost-effectively. In the coming years, he believes this technology will help “supply power to Indianapolis and West Lafayette and even Manhattan” — though convincing the energy sector to sign on won’t be easy. “Right now, natural gas is very cheap. No one wants to spend money,” he says. “But natural gas is a finite resource. In some shape and form, the human race needs efficient production and storage of electricity. This has to be built.”
– Jennifer Miller, http://bit.ly/2jEiDaY
Above: Illustration by David Senior.