Oxford Brookes University finds vertical turbines more efficient
Oxford Brookes University
(OBU) announced that it has found that vertical turbine design is more
efficient than traditional turbines in large scale wind farms, and when
set in pairs the vertical turbines increase each other’s performance by
up to 15%.
A research team from the School of Engineering, Computing and Mathematics
(ECM) at OBU led by Professor Iakovos Tzanakis conducted a study using
more than 11,500 hours of computer simulation. According to OBU, it showed
that wind farms can perform more efficiently by substituting the traditional
propeller type Horizontal Axis Wind Turbines (HAWTs), for compact Vertical
Axis Wind Turbines (VAWTs).
VAWTs spin around an axis vertical to the ground, as opposed to the traditional
propeller design (HAWTs). OBU outlined that the research found that VAWTs
increase each other’s performance when arranged in grid formations.
Professor Tzanakis comments “This study evidences that the future of
wind farms should be vertical. Vertical axis wind farm turbines can be
designed to be much closer together, increasing their efficiency and ultimately
lowering the prices of electricity. In the long run, VAWTs can help accelerate
the green transition of our energy systems, so that more clean and sustainable
energy comes from renewable sources.”
Lead author of the report and Bachelor of Engineering graduate Joachim
Toftegaard Hansen commented: “Modern wind farms are one of the most
efficient ways to generate green energy, however, they have one major flaw:
as the wind approaches the front row of turbines, turbulence will be generated
downstream. The turbulence is detrimental to the performance of the subsequent
rows.
“In other words, the front row will convert about half the kinetic energy
of the wind into electricity, whereas for the back row, that number is
down to 25-30%. Each turbine costs more than £2 million/MW. As an engineer,
it naturally occurred to me that there must be a more cost-effective way.”
The study analysed many aspects of wind turbine performance, with regards
to array angle, direction of rotation, turbine spacing, and number of rotors.
It is also investigated whether the performance improvements hold true
for three VAWT turbines set in a series.
Dr Mahak co-author of the article and Senior Lecturer in ECM comments:
“The importance of using computational methods in understanding flow physics
can’t be underestimated. These types of design and enhancement studies
are a fraction of the cost compared to the huge experimental test facilities.
This is particularly important at the initial design phase and is extremely
useful for the industries trying to achieve maximum design efficiency and
power output.”
