UNH Engineering Students Build a Better Delivery Box for a Piping Hot Pizza

Ravi Gorthala, associate professor of mechanical engineering, asked students in his "Heat Transfer" class to take a real-world problem and solve it. One team of students set out to solve a problem that has vexed pizza lovers everywhere. While some pizza delivery personnel have insulated, thermal pizza bags, sometimes heated by electrical heating elements, the UNH students focused on those who pick up their pies and still have 15 or 20 minutes or more to travel home and on those delivery persons who drop off pizzas that are lukewarm at best.

Their tests indicated a pizza just out of an oven is typically 167 degrees Fahrenheit. They found studies that showed that people tend to like pizza served at about 122 degrees.

After design work and a great deal of testing (and tasting), the engineering students created a pizza box fashioned from wood that the cardboard version can slide right into.

"It is exactly the kind of experiential, STEM-entrepreneurial learning that we want for our students," Gorthala said.

Inside the wooden box are compartments that hold phase change materials (PCMs). They change from solid to liquid at a constant temperature and store thermal energy when heated. They release heat and change phase back to solid when cooled. The temperature difference between the pizza and the surrounding PCMs is small, so the pizza does not lose heat and maintains its temperature. RGEES, LLC, a company based in Asheville, NC, donated PCMs to promote experiential education. The students heated the PCMs to different temperatures and placed them in plastic bottles.

In one experiment, the bottles were inserted into the wooden box at 127 F and 136 F (phase change temperature) and that kept the pizza at optimal temperature. Two hours later, the pizza was 115 F, still hot, Gorthala said. Six hours later, the pizza was still quite warm.

Gorthala guaranteed an A for the project if the pizza brought to the final class presentation in the prototype box was piping hot in 40-degree weather. The pizza was devoured and the students’ project received an A.

And now, the engineering students have a pizza restaurant to collaborate with, a place to test and further develop their prototype this fall.

Donato Cappetta of Cappetta’s Italian Imports, Pizza & Catering, just down the road from UNH at 188 Boston Post Road, saw a story about the pizza box invention on UNH’s Facebook page. He thought it was a great idea and wanted to see how they could get involved. He and his brother Luigi Cappetta, `94, a graduate of UNH’s hospitality management program, invited Gorthala to the restaurant and they discussed a plan over pizza.

Cappetta’s mother, Palma, is the original owner, and she still cooks often at the restaurant. Cappetta said UNH students stop in all the time for subs and the Donato Special – pepperoni, sausage and mushroom pizza. "We’re neighbors; we’re both in Allingtown and we love the University," Cappetta said. "We’re excited to work with the students. It’s a win-win for both of us."

Gorthala said he is thrilled with the collaboration and called the entrepreneurial venture "the hot topping" on a delicious STEM (science, technology, engineering and math) education pie. UNH engineering students typically experience the engineering process from concept to prototype. But now they will be able to experience taking a prototype to market, working with the Cappettas by combining engineering, economics, functionality, aesthetics and safety through different experiments to make the design feasible. "It is exactly the kind of experiential, STEM-entrepreneurial learning that we want for our students," Gorthala said.