See how Amped Innovation developed the EasyFreeze100, a 100-liter solar-powered freezer that redefines off-grid refrigeration.
In rural Africa, refrigeration isn’t as simple as buying an appliance and plugging it into an outlet because, well, that outlet doesn’t exist. According to The World Bank, only 30% of Africans living in rural areas outside of North Africa had access to electricity in 2021. Access to refrigeration, in particular, is key to the advancement of health, to the prevention of waste, and even to meeting many of the United Nations’ wider Sustainable Development Goals (SDGs).
Amped Innovation, a social venture in the Autodesk Foundation‘s portfolio, developed EasyFreeze100, a 100-liter solar-powered freezer, to redefine off-grid refrigeration in rural Africa and work towards a future where everyone has access to refrigeration and, in particular, freezing. Amped Innovation’s line of affordable solar-powered appliances has impacted 300,000 lives so far, a number that will only grow with the addition of the EasyFreeze100.
Amped about the cooling power of thermal batteries
Amped Innovation’s goal is to, “build affordable solar products that perform as well as an on-grid experience in off-grid areas,” says Amped Innovation Co-founder Andi Kleissner. With the EasyFreeze100, users can switch between fridge and freezer mode with the tap of a button. They can also choose to power the freezer by solar power or from the grid, depending on available resources.
The EasyFreeze100 utilizes thermal batteries, which Kleissner describes as “basically ice packs.” Using solar energy, thermal batteries create a wall of ice against the evaporator coils used in the cooling mechanism. Evaporator coils are a standard feature of fridges that pull heat from the air so the air cools. In the evenings or on cloudy days, the wall of ice on the evaporator coils slowly melts, dispersing the cold throughout the fridge to keep its contents chilled. A fan inside the chamber gently swirls the air around to provide a consistent temperature throughout the chamber.
Digital prototyping with Fusion 360
The Amped team collaborated with the Autodesk Foundation and Engineering for Change (E4C) fellow, Francisco Plaza, to bring the current version of the product to life. The Amped engineering team was based in California and Plaza was based in Ecuador. Logistics could have been tricky, but collaborating on the cloud with Fusion 360 made the process a breeze.
In fact, Amped used Fusion 360 for every stage of product development, from digital prototyping all the way through to marketing. “Once we received Fusion through Autodesk’s Technology Impact Program, it didn’t take us long to get used to it,” says Kleissner. “It was a fast learning curve.”
One of Plaza’s main tasks was to perform sensitivity analyses. Amped wanted to know which elements had the most effect on the time it took for the fridge to get cold and how long it would stay cold even if there was no external power.
Plaza started digitally prototyping in Fusion 360 by 3D modeling different iterations and running simulations. Based on the results, he recommended experiments for the engineering team to run in the lab. These experiments confirmed Plaza’s findings before they were incorporated into the final design. And every time, data validated the results.
Plaza ran sensitivity analyses on everything from the gaskets to the insulation to understand which components were worth spending more money on. The gasket’s price didn’t end up having a large impact on cooling. However, Plaza’s simulations showed insulation thickness did have a significant impact. As a result, the team diverted investment from the gasket to the insulation thickness to achieve the best dollar-to-value ratio.
Plaza also leveraged Fusion 360 to optimize the evaporator coils and thermal battery. Like a typical fridge, Amped’s current design had evaporator coils on the inner four walls of the rectangular box, but this increased design complexity and cost and required many thermal batteries.
The team was curious if they could simplify the design to evaporator coils and a single thermal battery on only one wall. “Francisco was able to optimize what size of evaporator coils and thermal battery we needed. Through his modeling in Fusion 360, he established that we could simplify our design and reduce costs, all while providing the overnight storage our customers asked for,” says Kleissner.
“The models in Fusion 360 were fast to design and easy to change, which helped with continuous iteration. Fusion 360 also made it easier to change the parts in context, so I could change the size of a fan and immediately see the impact on the larger model.”—Francisco Plaza, Engineering for Change Fellow 2021
Although certain areas of the fridge were cooling well, others remained too hot: there was too much of a temperature gradient from the top to the bottom of the fridge. The looming question was: What type of convection needed to happen?
Using Computational Fluid Dynamics (CFD) on the model he created in Fusion 360, Plaza was able to simulate the airflow within the freezer. His analysis showed that a low-power fan was the best option, so the engineering team in California added a fan to their prototype. The fan helped push warm air next to the thermal battery, eliminating stagnant areas of warm air with the added benefit of speeding up the cooling process.
The power of visualization: marketing and beyond
Even though the design was finished, Amped’s usage of Fusion 360 wasn’t. It can be hard to visualize a product before its first production run, so Amped created renders with Fusion 360 to help them make aesthetic decisions.
“When we weren’t sure how we wanted the product to look, we could create different versions,” explains Kleissner. “After visually seeing what the different colors and individual parts looked like in the render, we decided on which one we wanted to move forward with.”
Sometimes, Amped uses the renderings even after they have a physical product. “We use the renders to communicate with vendors, our wider team, and customers,” Kleissner continues. “It’s also hard to get a beautiful photo of the unit. We can create cool perspectives with the renderings, so we use them for LinkedIn announcements and the product catalog. Rendering with Fusion 360 is fast because it’s on the cloud, exporting it is easy, and collaboration is easier because multiple people can work on the model at once.”
What’s next for the EasyFreeze100?
After just two years of development, the first 20 EasyFreeze100s reached customers in Africa in 2023. Amped is already hearing that customers love the product and want more—double the volume. With the help of a new round of funding, Amped is in the process of implementing customer feedback into the next generation of the EasyFreeze.
“We’re never done with product design,” says Kleissner. “We’re going to keep getting feedback and iterating based on what we hear, so we can keep moving towards the best product we can make.”