May 30 2013
The great artist Leonardo Da Vinci once said, “Those who are inspired by a model other than Nature, a mistress above all masters, are laboring in vain.” The developing field of biomimicry seeks to learn from “the world’s greatest teacher” by modeling technology after organism’s unique features. This form of engineering is now being applied to the world of renewable energy sources as shown in two of the devices discussed below: BioSTREAM, a tidal energy device, and turbine blade tubercles, a wind harnessing device. The competitive nature of natural selection demands efficiency, which is key to maximizing the potential of energy generating devices.
The organization Bio Power Systems created BioSTREAM to harness tidal and current power. This device mimics thunniform swimming species such as tuna that organisms that propel themselves through the water using only the latter third of their body (shown to the far right in the image below).
The hydrofoil looks like the tail fin of a fish and moves in a swimming motion through the water around a single point of rotation. A computer continually adjusts the device so that it optimally flows with the current, similar to how wind turbines turn with the wind. The device is designed for currents at a minimum of 2.5 m/s. In order to capture the kinetic energy and convert it to electricity, Bio Power has created the O-Drive, which is attached to the BioSTREAM. The O-Drive uses “a hydraulic system and an AC-DC-AC power conversion system.” BioSTREAM is intended to generate 250kWh however it is still in the development stage and will not be deployed until the company’s BioWAVE technology is finished.
A video about the device being tested can be viewed at the link below:
Another emerging biomimetic technology is the whale inspired both turbine to be used both above and in water. A Canadian company called WhalePower has studied the unique bumps on the humpback whale fins, known as tubercules, which create channels for the water to pass through. This results in vorticies that reduce drag through the water and create lift. When testing in a wind tunnel against a turbine without tubercules, researchers found that the bumpy whale-like turbine had 32% less drag. This discovery has the potential to increase power output of future wind farms.
Researchers are also intrigued by this discovery because it may solve the issue of turbines stopping in low flow tides. Mark Murray, a USNA mechanical enginering professor elaborates on the issue: “A lot of the turbine designs, at very slow speeds, aren’t producing lift because the flow on the upper surface is separated.” WhalePower currently has the technology patented, but hopefully this will not impede adaption of the innovative advancement.