Solaraya – helping underprivileged communities around the world who don’t have access to clean water


Solaraya UCalgary, Calgary, AB

Building a solar-powered water purification device to clean up water in developing countries near the equator (tech focus: renewable energy & mechanical engineering)


Team Grade Level:  2nd-3rd yr Bachelors
Team Experience Level: Advanced
STEM Focus: Water Purification


Hi everyone! We’re Solaraya, a team of engineers from the Schulich School of Engineering, and we want to introduce you to our water purifier, the Solaraya. The Solaraya consists of two barrels joined via a coiled PEX pipe. The first is a refillable steel barrel with a clear lid, where the operator pours dirty water in. The second is a wooden barrel where the water will be deposited after the purification process. Situated above the first barrel, there lies a large aqua lens which is essentially a lens composed of water and a clear bathtub liner. The initial inspiration for the aqua lens came from this YouTube video. The lens is supported by four joists connecting it and the steel barrel. Solar rays travel through the lens and are concentrated in the barrel about one-third of the way from the bottom. This distance of one-third was chosen as most incoming energy needs to be absorbed by the dirty water, not its container. The concentrated sunlight will then allow the water to boil and create purified steam.

The steam will then travel through the pipe into the second barrel following purification. The coiled tube is used to increase surface area and facilitate water vapour condensation. A pressure gradient between the barrels must be present to force the steam to go towards the wooden barrel. We’ve employed a simple yet effective solution to create this pressure gradient. The design will be accompanied by a hole covered with filter paper at the top of the wooden barrel. This exposes the clean water barrel to atmospheric pressure, pulling the steam from the first barrel towards the second.

The expected outcome is to achieve 13.25 litres of water daily based on calculations done using commercially available materials, an efficiency of 30%, assuming 11 hours of sunlight, thermodynamics, and a little bit of astrophysics.

Further, a cost analysis was performed to compare our water purification device to other devices of its kind. Using the amount of water purified per dollar, it was determined that the SolaRaya is six times more efficient than the leading competitors.

The bottom of the steel barrel is lined with carbon black, which functions to trap heat. The steel barrel’s base and sides are insulated using shredded denim, which we will collect from used denim clothing. The barrel for the unpurified water is composed of a wooden outer framing. The wood making up the clean water barrel must be coated with a waterproofing, non-toxic sealant. For this, a combination of Beeswax and mineral oil will be used. The waterproof sealant of the wood barrel lasts two years, becoming the limiting factor for the lifetime of the SolaRaya.

The only suitable clean water barrel that was commercially available and suitable for our use has a volume that can hold the equivalent of purified water from 8 SolaRaya devices. Due to this, we’ve decided to have a second design that will connect the oversized clean water barrel with eight devices, putting the daily purified water output of the SolarOctopus at 106 L.

We want to use Solaraya to help underprivileged communities around the world who don’t have access to clean water.



Posted on

June 16, 2022

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