About SOlar-A

Around the globe, an estimated 784 million people do not have access to clean water. This inaccessibility is one of the biggest factors perpetuating the cycle of poverty, as individuals must allocate their valuable time and limited resources into gathering and purifying their water. 

Approximately 16% of the citizens of Honduras, 638 000 people, live in rural areas and do not have access to clean water. Many organizations have made progress in improving water access, however, remote regions with more challenging topography experience bigger obstacles in transporting clean water. Solar-A aims to provide a new solution for communities in these regions by introducing a backpack-like water filtration device. Instead of the traditional bucket-on-head technique, this device’s shape can distribute the weight onto the shoulders and hips comfortably. 

Not only is this backpack more practical, but it will also be affordable. We aim to locally source as many materials as possible to increase our product’s durability and tailor it to the users’ financial needs. Plus, Solar-A will improve the efficiency of the time dedicated to water transportation by allowing the water to be filtered as it is being transported.

Our team is composed of four different sub-teams – the pre-filter team, the biomechanical harvester team, the sensor team, and the jug and support team. The water begins by flowing through the pre-filter, which gets rid of the bigger debris and turbidity, while maintaining a fast flow rate. Next, it enters the jug to be filtered using the solar UV rays. Here, the jug and support team must take into consideration the design and material of the jug such that it can minimize the filtration time, while maximizing the comfort of the user. Subsequently, the user must be able to tell when the water is potable, hence the sensor team worked to create a reliable sensor. Lastly, the biomechanical harvester team will transform the walking motion of the user into energy to power this sensor. Putting all the parts together creates a novel solution to aid in the water crisis.

Carousel imageCarousel imageCarousel imageCarousel imageCarousel imageCarousel imageCarousel imageCarousel imageCarousel image



Before the purification process, the water flows into the jug through our pre-filter, attached to the entrance of the jug. The purpose of the pre-filter is to remove large debris and particles to increase the filtration rate. Directly following the pre-filtration, the water will go through a filtration module which removes contaminants that solar water disinfection (SODIS) cannot remove, such as heavy metals and chemicals. The filtration system is connected to the entrance of the jug, below the other pre-filter, and consists of a cylindrical cartridge with five layers: support mesh, filtering cloth, activated charcoal, another filtering cloth, and another layer of support mesh. The water flows through the five layers of the cylindrical cartridge radially for maximum flux. Our cartridge was inspired by existing designs on the market and allows the system to remain solidly in place without any risk of the biochar falling out. By using SolidWorks 2020, we created our own simpler and cost-efficient design, which will be 3D printed with the same PET filament as the pre-filter for the same reasons listed above. The next steps include building the prototype to optimize the speed of filtration while maintaining high filtration.


Another important issue with SODIS is the user’s inability to recognize when the water is safe to drink. To address the lack of visible indication of potability, we incorporated a sensor. The sensor aims to detect solar UV such that it can accurately determine when the water is fully potable and respects the USEPA guidelines. Despite sensors usually being expensive and considered a luxury, we deem it a necessity for their health and are working towards making it as affordable as possible. The first prototype has an integrated UV sensor powered by a rechargeable battery to accurately determine the amount of UVA and UVB entering the jug and compare them to the amounts required to clean water. Different iterations have been created, along with their respective casing and the team is now working with the jug and support subteam to conduct testing.


The harvester subteam has been working hard to convert the walking motion of a user into electrical energy. The harvester uses inductance to generate electricity from the potential energy of oscillating magnets moving through a copper coil. The main components of the harvester are easily accessible materials: a linear rail and carriage, a magnetic mass, end walls, magnets, copper wire, and a spring. The end walls, fastened to either end of the linear rail, will act as supports to hold both the added magnets and spring. The spring will be directly attached to the magnetic mass, which will allow the user to pull the mass and deform the spring. When the user releases the mass, the potential energy of the spring will slide the mass along the linear rail in an oscillating motion. To aid this motion, magnets will be fastened to the end walls to either pull or push the magnetic mass, allowing for faster and more frequent oscillations. Finally, coiled around the linear rail will be copper wire through which the magnets will pass to induce a current and consequently create power for the electrical components of the backpack. Additionally, the continuous walking motion of the user as they transport the water will allow the mass to continuously oscillate for a longer time and create more power. Over the next few months, the team will experiment and improve this mechanism to provide enough power to charge the sensor’s batteries, 95mW.

Jug and Support

SODIS is already used in many developing countries, but it takes many hours to complete the process and access fully treated water. To attempt to solve this issue, we conducted experiments to optimize purification time and jug durability by comparing different jug materials and by incorporating an aluminium-lined backing for the jug. They selected a jug with highest UV transparency and dimensions to improve efficiency of the filtration, while remaining sturdy and low-cost. The additional aluminium backing will reflect the solar rays back onto the water, increasing the impact of incoming solar UV rays. They have already started testing the jug using Escherichia coli infected waters and are now mainly working on improving the comfort and flexibility of the support design.



Global Impact


Watch to learn more about us!

Team Leads

Bernadette Ng

Bernadette is a U3 Mechanical Engineering student, aspiring to help the projects in McGill Biodesign grow and succeed. As one of the team leads of Solar-A, she is looking forward to working, learning, creating, and designing alongside a team of dedicated members. When she isn't studying in MD-50 or McLennan, catch her at the Fitness Center deadlifting or training with her dragon boat team.

Tirza Peng

Tirza is currently co-leading the SOlar-A project with Bernadette Ng. She maintains communication between each subteam leader to help with the progress of the project and ensure that the team runs cohesively.

Tirza is currently in her third year of chemical engineering and enjoys exploring new ice cream places, but she always comes back to McGill's Frostbite for the Toonie Tuesdays!

Subteam Leads

Neil Banik

Sebastien Gaviria Velez

Zoe Goldberger

Leah-Kathleen Lavoie

Frank Li

Mary Wan

In the media: