Turning theory into practice

How do you manage a four-year crop rotation on a farm with chickens and irrigation? What is the best design for a large-scale moving chicken coop? How can farmers in India dry their chilis in an energy-efficient way to improve the shelf life and value of their crops? In one mechanical engineering course, students tackle these kinds of problems and engineer solutions through a living laboratory on campus: the O’Donohue Family Stanford Educational Farm.

ME 170: Mechanical Engineering Design: Integrating Context with Engineering is a two-quarter senior capstone course in which students apply the lessons they’ve learned in the mechanical engineering major to solve a real-world problem. While the projects span a range of topics –refining wind power, improving walking gait for children with cerebral palsy, and scaling the thermal storage technology at the Central Energy Facility – the Stanford farm has served as a primary experimentation space for students working on agriculturally focused solutions.

The instructor, Jeff Wood, brings 25 years of industry experience to his instruction at Stanford. He partners with companies and public agencies in addition to Stanford organizations like the Precourt Institute for Energy, the Woods Institute for the Environment, and the School of Medicine to find compelling problems in energy, transportation, and health involving thermal, structural, and mechanics challenges. The course is certified as a Cardinal Course by the Haas Center for Public Service because of its engagement with projects that address social or environmental challenges.

A space for research

The course pushes students to develop engineering skills they might not have previously considered, such as how to communicate the significance of the problem to a broad range of audiences. It also emphasizes the ethics of engineering by requiring student groups to answer challenging questions associated with their projects.

“We really want [our students] to grapple with what it means to be an ethical engineer in addition to a good technical engineer,” Wood said. In a chili-drying project, students were asked to design something based on someone else’s culture and worldview – an essential perspective for bridging boundaries between experimentation and implementation. The group assessed how their project would impact labor conduct and ensured their technology would not replace farm workers who were already struggling to make ends meet.

Because the Stanford farm is designed as a space for research, student groups are able to return and build on the previously designed projects year after year. As a result, after the chili-drying project tested on the farm eventually scaled up to a business practice in India, future groups were able to tackle other aspects of the problem.

After one class group developed a small “grow house” that acted like a mini solar greenhouse, the idea spanned multiple classes and evolved over time. While the majority of the grow house space stored heat with water thermal storage, the remaining space was used for drying the chilis. By demonstrating the concept could work on 55 pounds (25 kg) of chilis, it was scaled up in India to accommodate 44,000 pounds (20,000 kg) of chilis.

“The farm was really important and very supportive of the team in being able to use the space, in being able to use their equipment, and ultimately generating their test bed,” Wood said.

Follow-up projects on chili drying in subsequent class years have included studying how to more evenly distribute the temperature throughout the system and develop a solution to recapture the water pulled out of the chilis during drying and convert it to drinking water for farmers in rural India.

Farm Director Patrick Archie said he is pleased with how the class utilizes the farm and looks forward to hosting research projects from other schools and departments in the future.