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ProFONDO - Coffee Pellet Machine

ProFONDO is a machine to reuse spent coffee grounds, daily produced in coffee shops. It aims to dry and pelletize this material so that it can be used as a fuel for pyrolytic stoves.

  • PROFONDO - Coffee Pellet Machine

  • CONCEPT DESIGN - Sketches and inspirations

  • INNER PROCESS - From spent coffee grounds to pellet

  • DESIGN DEVELOPMENT - Technical Drawings and 3d models


What it does

This project aims to reduce waste and encourage the recycling of spent coffee grounds by turning this biomass into pellet. Businesses like coffee shops could help the environment and save money by producing a zero-mile pellet to provide heating autonomously.

Your inspiration

The idea comes from the emerging interest for the properties of spent coffee grounds and the need to dispose of this material giving new life to something considered waste. Much of this biomass ends up in landfill, emitting harmful gases such as methane, and increases the carbon footprint because of energy spent to move hundreds of thousands of tonnes of material every year. Since 2012 things changed because many scientific papers were published about the use of coffee as a fuel. In the meanwhile wood pellet production has more than doubled and new heating technology, such us pyrolisis, have been developed to burn biomasses with low emissions

How it works

ProFONDO combines two main technologies: drying and pelletization. Drying is necessary to decrease humidity from 55-75% to 10-15%. Pelletization is a mechanical process which compresses the biomass and rises its temperature up to 70-80° C. This temperature allows the lignin inside coffee to soften and act as a glue. More specifically, spent coffee grounds, after being collected during the workday (average is 2,5 Kg), are poured inside the machine. The biomass arrives directly in the heating chamber, which is a metal container equipped with flexible heating elements. A mixer, moved by a brushless gear motor, ensures the homogeneity of the process. A capacitive sensor measures the temperature and when drying is finished, the chamber opens and coffee goes down. Here there are two rollers that force the biomass to go through the holes of a die matrix where, thanks to mechanical pressure and heating, it turns into pellet and is collected inside a container.

Design process

ProFONDO has been developed in different stages: from a deep research till a conscious engineering process. The first step was to understand all the topics and issues that go around this project like properties of spent coffee grounds (such as chemical composition and calorific power), context of use (e.g. amount of biomass produced per day), scenario (e.g. energy consumption and heating costs), pellet production (e.g. technologies needed to pelletize a biomass). Since this project was a new kind of product, with no references on the market, I started to visualize it by means of sketches and 3d models. I defined the most resonable layout able to meet the requirements and I started to assembly the different components taking into account my concept design. Once everithing was quite clear I started with the engineering stage. Buy components (such as sensors and heating elements) were identified and forces at work were calculated to select a gearmotor able to meet the requirements. To test the frame and some mechanical components I used simulations and FEM analysis. After having assembled every single part going into detail, I ended with drawing up of technical drawings and selection of materials and manufacturing processes.

How it is different

This is the only existing product designed to allow small coffee shops or big chain coffeehouses (such as Sturbucks or Costa Coffee) to avoid the waste of spent coffee grounds by turning them into pellet that it is possible to use with pyrolytic stoves to heat autonomously the environment. Coffee pellet is a current and concrete reality because some private companies are already responsible for collecting coffee grounds to transform waste into valuable products thanks to pelletization or chemical processes, but they work at an industrial scale. So currently coffeehouses that disposes of this material do not get directly the benefit of their action while this project aims to reduce the supply chain giving them the possibility to produce a zero-mile pellet that could be burnt with low emissions. Moreover, the project is designed to stay inside the shop, close to customers so as to arouse people's attention and building the knowledge about reuse of coffee grounds

Future plans

In the next future I want to raise awareness about the several ways to reuse spent coffee grounds and I hope to contribute, even in a small way, making people know that it is possible to use this biomass to produce energy and fuels. This is very important because in the next years people will have to find alternative and sustainable energy sources as well as trying to reduce carbon emissions. In terms of development and strategy I would like to go more in deep in a perspective of production making a business plan and looking for investors to turn the project into something real able to help the companies and the environment.


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