Solar-power oven project continues

by Jason Juno

Student projects do not always die when the class ends.

One student is continuing to work on a solar-powered cooking system that started from five other students’ projects in a class last spring.

The project, similar to a stove, is continuing thanks to funding granted by the Initiative for Renewable Energy and the Environment.

But don’t expect this in your house or apartment anytime soon, said William Durfee, professor and director of design education in the department of mechanical engineering.

He said he focuses on areas such as Nepal, where firewood they use to cook is a pollutant, and its supply is continually dwindling. Carbon-based fuels cannot get to those areas.

Durfee said this project might also have some value

in Minnesota, in areas such as the Boundary Waters Canoe Area Wilderness. It also can help in high pollution areas, he said.

The project received $40,000 for 12 months of work from the renewable energy initiative, he said. It is funded with approximately $20 million spread over five years from the state and Xcel Energy’s conservation fund.

A lot to live up to

Durfee said the project will be time consuming for graduate student Diego Bonta, who is working on the project.

The original group, the spring 2004 Design Projects class, (ME 4054), made a lot of progress. They started with nothing and built a prototype in five months with “almost no money,” Durfee said. Building the stove’s prototype in a semester is rare, he said.

“These guys set the standard,” he said. “So we really have to work hard to do as well as they did.”

The project started with the Minnesota Office of Environmental Assistance, part of the state government. The office knew of the needs for a different power source in developing countries, such as Nepal, Durfee said.

How it works

Energy can already be obtained from solar panels, but Durfee said the sun has to be out, which is where the hydrogen comes in.

After the sun hits the solar panel, the electricity goes through an electrolyzer that converts it to hydrogen.

The hydrogen is then stored in a tank, for use whether or not the sun is out, he said. Hydrogen is then used as fuel.

Hydrogen is explosive, Durfee said, but if done right – as gas stoves are now – the risk is minimized.

Project’s path

When the project is finished, group members will demonstrate the next prototype.

They plan to show where the technology is at the end of the project and look into the future to see where it will be in five to 10 years to investigate its marketing potential, Durfee said.

He said usage is not imminent, but the demonstration of a more efficient product should get people excited of what is to come.

The solar-powered stove would not likely be applied to large energy users because the application now is for small-scale stoves.

Business-wise, it might turn out the purchase will have a high price, but money could be saved if it lasts a while, because of the savings in using renewable energy, Durfee said.

A student from the Humphrey Institute of Public Affairs will be assigned to the project for economic analysis, said Laureen Ross McCalib, interim associate director of the renewable energy initiative.

Bonta said he expects challenges from the business aspect of the product.

“Any alternative energy system is going to be cleaner than conventional fuel sources,” he said. “Making them competitive cost-wise is the big deal.”

Mike Port, executive director for the Solar Oven Society on Hennepin Avenue in Minneapolis, said a solar oven can be affordable. The solar oven that the company produces changes sun rays to heat rays to cook an entire meal, he said.

He said 2.4 billion people in the world do not have adequate cooking fuel, and most live where the sun is out often.

“We’re trying to reach the masses of the world that lack adequate cooking fuel,” Port said.

He said he supports any advances in the technology.

However, Durfee said the process lacks efficiency so far. The prototype is approximately as tall as a typical door and fairly wide.

Bonta’s project, which involves the electricity-to-hydrogen step, has the potential to make ovens more efficient, Durfee said.

Bonta said he wants to come up with an oven that maintains a certain temperature.

“Hopefully, sometime in the future, it will have a use and be on the shelf,” he said. “That’d be exciting.”