McCormick Magazine

Powering student projects

Each year, members of the Walter P. Murphy Society fund student and faculty project proposals ranging from student-group projects to new laboratory gear to the development of new course work. These stories follow the trials and successes of two Murphy-funded student projects.

Email::

patrick markanDown to the wire in a solar car
On a rural highway somewhere between Texas and Canada, Patrick Markan (mechanical engineering ’09) watched as people gawked. They waved. They slowed down to stare. They pulled ahead onto the shoulder and got out their cell phone cameras, clicking away as the car rolled past.

Then they drove off — burning gas, spewing exhaust — to the next gas station to fill up, while Markan and the rest of the Northwestern University Solar Car Team continued on, using only sunlight and battery power to make their way across the continent.

The team was participating in the North American Solar Car Challenge, in which 15 college teams raced solar-powered cars from Plano, Texas, to Calgary, Alberta, over 10 days last July. The Northwestern team placed 13th in the race, overcoming a fried motor controller and a blown-out tire to coast to its best finish ever. The race was two years in the making for the Northwestern team. Building a solar car requires not only a year of design work but also endless hours of fundraising, getting donated equipment, and reaching out to teach about the possibilities of solar power.

Before the team could get on the road, however, they had to finish another race: completing the car. Critical suspension components for the vehicle — called sc5 — arrived just a month before the race, and team members were still waiting on donated equipment needed to actually drive the car. It all arrived within the next two weeks. “Luckily, the first time we put it all together, it worked fine,” Markan says.

The car runs by capturing solar power using solar cells. When sunlight isn’t abundant, it runs on a lithium ion battery — which means team members had to consider sunlight and battery power to determine how fast and long they could go each day.

Each morning during the Solar Challenge, team members charged the car’s batteries from 6:30 to 8 a.m. Then they drove until 6 p.m. before spending the evening charging the battery and working out bugs. Each driver drove up to six hours, while the other team members drove in vans in front of and behind the car; an additional truck pulled a trailer to haul the solar car, if it came to that.

“It was pretty exciting,” Markan says. “You’re always monitoring what’s going on with the car, deciding how fast to go, looking at the weather. Inside the car, the motor was really loud, and in Texas it got pretty hot.”

The race took the cars along secondary highways, where team members sometimes had to pull over to let traffic pass. That’s where the gawkers came in. “Some would just ride alongside us at 30 miles per hour and look out the window and wave,” Markan says.

In the end, the team finished the race in 113 hours and 58 minutes to take 13th place — Northwestern’s best finish in its 10-year history with the race. This sc5 car will spend the rest of its days at outreach events, and team members hope to tend to details that they never got to before the race — like installing a speedometer.

“We learned a lot,” Markan says — and now they’re passing that knowledge on to the new team members who ogled the car at a new member kickoff meeting in September. The learning began immediately — the team will waste no time before beginning work on a sixth-generation solar-powered vehicle, which will race during the summer of 2010.

Shuttle buses go green — with a little help from the deep fryer
nu solarEvery week the dining halls on Northwestern’s Evanston campus produce nearly 170 gallons of waste vegetable oil. In the same amount of time, intercampus shuttles use anywhere from 200 to 300 gallons of diesel fuel to transport students and faculty between the Evanston and Chicago campuses.

Math and logic point to a possible solution: adapt the shuttle buses to run on vegetable oil instead of diesel fuel. Implementing such a change has been years in the making, and recently a group of Northwestern students found that even great plans take a lot of work.

The idea to have the buses run on the oil was proposed two years ago by Engineers for a Sustainable World, a Northwestern student group that works to reduce poverty and improve global sustainability. Aaron Greco, a PhD student in mechanical engineering working on the project, can quickly list the benefits of such a system: The emissions are cleaner, with no sulfur and fewer particulates, and the net carbon contribution to the environment is significantly less than that of diesel-fueled buses.

Since the idea first blossomed, students in both Engineering Design and Communication and Segal Design Institute courses — taught by both McCormick and Writing Program faculty — have worked on various aspects of the project, from oil-quality testing to cost analysis. Though student teams got off to a good start on the project, many of their ideas, as often happens, just didn’t work out. Last winter a team made up of Charles Weschler (political science ’08), Rebecca Hoo (biomedical engineering ’09), and Ji Hun Lee (industrial engineering ’10) took on the project and came up with a whole new operation, from collection to filtration to distribution.

Their plan works like this: Each week three students take a University-owned truck and drive around to gather the 55-gallon drums of waste vegetable oil from dining halls. They then pour the oil into a large vat that acts as the first step of the filtration system. They let the oil settle for a week — allowing the large particles of food and sludge to sink to the bottom — before pumping out the top oil through a small filtration system. The result is vegetable oil with no water or particles larger than five microns in size — clean enough to run a modified diesel engine.

In fact, the team created a prototype diesel engine that runs on vegetable oil and gives off not the odor of diesel fumes but rather the scent of campus-staple French fries. But what’s a little fried-food smell compared to a cleaner, more sustainable system? “It saves hundreds of dollars a week in diesel fuel,” Hoo says.

nu solarWhile developing the operation, students say that, in addition to learning about the fine points of filtration, they learned about dealing with systems and people. “We learned how to create a system from scratch,” Weschler says. “It was the first time I helped create something that was working in real time and had a real-life application.”

The team also learned about compliance with regulations — like the rule that only certain colored barrels can be used — and learned that the most important part of executing a plan is often not the plan itself. “We ran into problems in terms of communication, so I think we learned how to better coordinate that,” Lee says. Managing the needs of the food service company, the bus company, and the University can be a job in itself, he says.

The last hurdle is converting the engine of the bus to run on the vegetable oil. The vegetable oil is much thicker than diesel, so the bus will need a conversion kit that uses the heat of the engine to thin the oil. “It’s actually not a major overhaul of the engine,” Greco says.

In the long run, the group hopes that the project will become part of the University, with students donating a few hours each week to make the system work.

“This project demonstrates an alternative that improves the sustainability of the traditional system,” Greco says. “By taking a waste product (used cooking oil) that is expelled from the campus and then reintroducing it into the campus system to be used as fuel for the buses, we are not only eliminating a campus waste stream but also reducing our demand for a nonrenewable resource. We hope this project will ultimately bring awareness to sustainability and to how these solutions can benefit the environment and the University.”

—Emily Ayshford