Students design an innovative mini Caja Fria fridge for communities in Peru

In Lobitos and Piedritas, there is only a single potable water pipe, and this only provides clean water for only two to three hours a day. With no other sources of clean water, this potable water pipe is used for everything.

After careful consideration and ample research, the team produced the Caja Fria fridge and filter system. Made from terracotta clay, the mini-fridge relies on the principle of evaporation to provide cooling to the contents of its interior. The fridge is designed to use water directly from glacial runoff, which negates the requirement to fill it with clean water from the pipe. Additionally, the water can be withdrawn and cleaned for other uses through its filter system.

For their brilliant efforts, the team won the Peoples’ Prize Award and the Grand Prize. IE caught up with the students, who are currently in their placement year, to talk about their invention.

For the people, by the people, and of the people

The NTU team was adamant from the start that their solution must be user-centric.

"The whole user-centered approach to the whole thing is quite important (because I know that you might look at it from a very engineering and product point of view). But how the product integrates into society is worth noting. From the research that was given to us, we know that the people in the Lobitos and Piedritas are very averse to accepting Western culture and they don't want Western solutions to be imposed on them," says Kapoor.

This made terracotta the perfect intervention "because Peru as a country has so much heritage in the terracotta sector. Making it was a popular art form, and the people used terracotta jars to store their grains and food. It's all about being able to integrate technology within the culture. Because if you don't keep that in mind, the solution can be amazing, but it's never going to be accepted," she continues.

Finding a material that was part of the country's natural resources was a significant step in their research. "When we're doing our initial research, we looked into what kind of raw materials are available in the area. And terracotta is one of the main resources that the area of Lobitos and Piedritas has in abundance. What makes terracotta special is the pores inside it - it keeps the water naturally cool when in contact," says Seekins.

As aforementioned, employing the cooling properties of terracotta is an ancient method. Caja Fria's unique-selling proposition lies in its filtration system. "It prevents the need to boil water, which saves energy as one doesn't have to use LPG.  So the drop in temperature that the fridge achieves is about 48 degrees, which might not seem like a lot, but for that particular area, it is a significant difference. And it can help keep their staple food, which is fish, a little bit cooler and prevent it from going bad," says Kapoor.

The internal structure of the Caja Fria is double-walled. "Like a water jacket where the water runs around. The filtration system was inspired by LifeStraw, a company that provides humanitarian aid. So not only can you keep your food cold, but once that's done you've 12 liters of usable drinking water. In the area, there are only two to three hours of water. So if they could store even 12 liters of water in kind of a clean environment, it's kind of a big deal for them," says Seekins.

Dennison mentions that the people in the Lobitos and Piedritas do not generally store food for much longer than 24 hours. "Just the fridge's ability to cool the food just even by a few degrees is enough to keep it safe throughout the day, as opposed to keeping it for like a week. And they've only got one potable water pipe that is active for two to three hours a day. So being able to use water from the fridge for domestic tasks, reduces the amount of water taken from that pipe. And it means that the pipe can just be used for drinking water," he says.

One for the economy

As the Caja Fria is terracotta-based, it eliminates the requirement for energy usage. "This allows them to use their capital or their money on other things. Typically, the average family would spend 25 percent of their income on energy. A fridge is energy-intensive. Here, they have a standalone fridge that just requires water. It's very rare for any of the kind of families in Lobitos and Piedritas to have access to the energy grid, so a lot of them are forced to use LPG to cook. So by using a fridge that doesn't use any energy, they could be able to ... spend money on things that are more important to them, rather than just keeping the food cold," notes Seekins.

The team didn't stop there. They were also insistent that one goal was to improve the livelihood of the people in the Lobitos and Piedritas.

"The whole idea that we would come up with this fridge was that they could make it themselves. There was a kiln, that kind of the village could access locally. So they'd be able to make it on-site and create an industry for it. Jobs would be generated," says Seekins. He also observed that the area was a tourist hotspot for surfing. "We thought that the people could get the hang of making terracotta fridges, mementos, or even souvenirs for tourists. So it kind of opens up like another sort of economy to provide money for the area. And they're the ones in charge of making it and kind of distributing it. So they don't feel like the Western culture is trying to take over."

Dennison says that part of the research for the actual competition involved setting up a kiln indoors than going all the way to the village that had one. "We looked into the possibility of making that happen as well."

A different set of challenges

"In terms of learning outcomes, empathy was very challenging, because it's a very unconventional location. And we didn't have access to direct users, any kind of research was given to us by EWB. So building that empathy was quite challenging, and especially when you want to integrate something so deeply within culture," says Kapoor.

Making the Caja Fria economically viable was another factor. "We wanted to make sure that it was affordable, fits the pocket, and was local. A product can be sustainable, but if it's being made in China, and we have to transport it from China to Peru, it's gonna have so much carbon footprint, and it's just not going to make sense anymore. So, keeping it local and relevant to the country was challenging. But I think the challenge was a bit of a driver," she says.

As evident, sustainability also took center stage. "I've always been interested in sustainability. But I think it was the first time that I viewed sustainability from its three pillars - planet, people, and prosperity. And so, this design is very people and planet-focused. But at the same time, it enables prosperity," adds Kapoor.

What's next?

"The Caja Fria project was just on paper. It didn't require us to make a physical prototype. However, during the later stage of the process, I 3D printed a couple of models to get a better idea of how the thing would actually look. Although granted, they weren't full size. But, once we've all finished university, we'd like to try to take the project further and see if it can be properly implemented for the people we designed it for," says Dennison.

Building the idea of a community around the product, integrating it into their culture, testing and seeing how they perceive it would be next, adds Kapoor.

Editor’s Note: This is a part of our special INTERESTING ENGINEERS ISSUE, where IE explores the greatest minds using ideas on the small scale to reshape the world on the big scale.