Engineers in the American Midwest hope to use precast concrete buildings techniques to create taller wind turbine towers as well as facilitate their transportation and construction process.
Researchers from Iowa State University's Structural Engineering Research Laboratory believe the use of precast concrete modules for the construction of wind turbine towers could have a profound impact on the installation and usage of renewable energy facilities.
The "Hexcrete" towers they've developed are capable of rising to far greater heights than the 80-metre steel wind turbine structures that currently dot the Iowa countryside. The use of ultra-strong concrete to form the precast columns and panels means the towers could potentially be as tall as 140 metres, enabling the wind turbines at their summit to harvest greater amounts of energy from the more rapid air currents that prevail at higher altitudes.
The researchers have sought to determine the durability and strength of the precast concrete structures under rigorous laboratory conditions, using actuators to apply 100,000 pounds of force to a 12-foot high and 6.5-foot wide test section consisting of two panels and two columns every 1.25 seconds during multiple weeks of fatigue testing.
According to Sri Sritharan, Iowa State University's Wilson Engineering Professor in Civil Construction and Environmental Engineering, the ongoing tests have already proven a success, with no damage detected following nearly 200,000 load cycles.
"It's fair to say these tests were a success," he said. "I think we've made great process in validating a new concept of using prefabricated concrete for taller wind turbine towers."
In addition to enhancing the energy generating potential of wind power facilities by enabling them to rise to greater heights, the use of precast concrete will also make it far easier for developers to build the turbine towers. The precast columns and panels that form the hexagonal segments of the completed tower are easier to transport to construction sites than conventional building materials, while assembling them is as easy as tying them together in order to form hexagonal cells that can then be stacked on top of each other.
Now that the mettle of the wind tower segments has been proven by strenuous fatigue testing, the next step to create a working prototype under real-life conditions, with a view to commercialising the prefab concrete technology.
"Now our goal is to build a full tower in the field," said Sritharan. "Our content is to identify partners who can work with us on a prototype tower. We'll also develop a commercialisation plan."