Get the Most out of WaterLily with These 8 Tips
There is no single right way to set up WaterLily as long as you are safely capturing fast moving water or wind - be creative! Our lead mechanical engineer has outlined these 8 Tips to effectively charge your devices with water, and get the most out of your WaterLily.
Find a Choke Point
If you take only one thing from this article, let it be this! A narrowing in the river is where you’re most likely to find the fastest flow. Look for a rock formation, or change in geography to cause a good choke point. They’re easy to spot since the water appears to squeeze into the narrow area, typically followed by a very turbulent section.
Above - The water is “squeezed” between two rocks - the water will be faster in the area where the arrows are pointing
Angles of the Water
WaterLily runs at its best when the blades rotate in a plane that is perpendicular to the flow direction. Accomplish this by tying off the turbine rope to something near the surface of the water - the line should extend as close to horizontal as possible.
Power = Velocity Cubed
Operating over a wide range of water speeds sets Waterlily apart from other hydro turbines, but finding the fastest flowing part of the river makes a big difference in power output. Here’s the equation for turbine power:
A = Swept area
𝝆=Density of fluid
𝒗=Velocity of Fluid
ɳ=efficiency (maximum .59)
Since the velocity term is cubed, small increases in flow speed have an exponential impact on power output! For example, if the flow rate at a choke point is 2x faster than at another location, you will harvest 8x more power! Have a look at our output curves in water for more information.
Here’s how Wikipedia defines turbulence:
In fluid dynamics, turbulence or turbulent flow is any pattern of fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow regime, which occurs when a / the fluid flows in parallel layers, with no disruption between those layers.
Turbulence is found at the base of a waterfall, or after an obstruction such as a rock. You can still harvest energy from turbulent flow, but it isn’t ideal. Most rivers flow over rocky, uneven terrain; Turbulence is unavoidable, but try to find a spot that looks like it’s flowing both fast and smoothly without too many bubbles, ripples and waves.
As mentioned above, the turbulent spot at the base of a waterfall (even a very small waterfall) is not an ideal location to deploy your turbine. The bubbles indicate a lot of turbulence, and the air bubbles reduce the density of the fluid which means it’ has less kinetic energy. You can set up in a bubbly spot a few feet past the waterfall, where the flow has redeveloped and is moving along swiftly.
You’ll harvest the most energy when the turbine is fully submerged, although small shallow streams are still viable charging locations in a pinch. You’ll find the faster flowing currents near the surface of deep rivers.
Resist the torque
As the generator extracts power from the spinning blades, it creates a torque that makes the whole WaterLily want to spin. This torque should be resisted by securing the cable to something on shore. Too much cable left out may get wrapped around the rope, or pull your WaterLily out of its optimum location.
So how fast is the water flowing in a river, anyway?
You can look at our power output curve all day, but without knowing the typical speeds of a river it’s doesn’t mean much! On the Island of Newfoundland, where flowing water is abundant, we have noticed that river flow rates are usually around 0.5 m/s in open flowing sections. Most choke points are faster, at around 0.9 occasionally as high as 1.5m/s.
In summary, get those blades spinning - FAST! The faster the blades are spinning, the more power you’re harvesting! We hope this article has been helpful!
If you have a question or a topic you’d like covered in a future blog post, please comment below! Happy camping! #rechargewithnature #gowiththeflow
Did you know that the technology behind WaterLily Turbine was developed for the ocean technology sector to provide power to scientific instruments deployed deep in the oceans? Deepwater ocean currents are significantly slower than a typical river - WaterLily’s patented design was developed to harvest energy from these super slow water currents of mere centimeters per second.
If the rotor is spinning, you’re creating power - through the faster those blades are moving, the more energy you can generate. Follow these recommendations to get the most power from your Waterlily Turbine!