A twin unidirectional turbine topology has been proposed as a power module for an OWC based wave energy plant. It has no valves or moving parts and demonstrates high efficiency over a broad range of flow coefficients. Scaling laws show that a turbine of 2.6 m diameter is sufficient to achieve a power rating of 2 MW, Thirty one such modules can be used to produce an annual output of 50 GWh.

Jayaraj Joseph

Department of Electrical Engineering

K. Mala

Sundarm Moses Santhakumar

ANNUAL OUTPUT

Flow coefficients

High efficiency

IMPULSE TURBINES

Moving parts

POWER MODULE

POWER RATINGS

Wave energy

Hydraulic turbines

WAVE ENERGY CONVERSION

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Design of a 50 GWh Wave Energy Plant

Proceedings of INDICON 2009 - An IEEE India Council Conference

The development of air turbines for wave energy conversion has been in continuous evolution starting from conventional turbine to self-rectifying turbine and still in progress. The turbines applied to harness wave energy via a pneumatic type system is called oscillating water column which either has a reaction or impulse principle of operation. The reaction turbines are simple in construction but possess weaknesses such as high rotational speed, less efficiency and narrow operating range. Favorably, the impulse turbines feature low rotational speed, high efficiency and wider operating range which made it inefficient. Recently developed self-rectifying impulse turbines too substantiate these features. In this paper, a review of various types of impulse turbine along with a comparative study has been presented. As a result, self-rectifying axial impulse turbine with linked pitch-controlled guide vanes and self-rectifying radial impulse turbine with active-pitch-controlled guide vanes are found to be predominant in terms of wide operating range of flow coefficients at useful efficiencies. A review of bidirectional flow turbine and a comparison with impulse turbines & reaction turbines have also been reported. © 2013 IEEE.

Proceedings - 2013 International Conference on Renewable Energy and Sustainable Energy, ICRESE 2013

Review of air turbines for wave energy conversion

The twin unidirectional turbine topology was recently proposed with the promise of very significant improvements in the energy capture in Oscillating Water Column (OWC) based wave energy plants. Here, we present the initial results of the experimental validation of the twin unidirectional impulse turbine topology. A scale model of the concept was built and tested using simulated bidirectional flow. The model consists of two 165 mm impulse turbines each individually coupled to 375 W grid connected induction machines. An oscillatory flow test rig was used to simulate bidirectional flow to test the model. The results of the experiments validate the concept of the twin turbine configuration. The proposed topology utilizes no moving parts and achieves more than 50% efficiency over a broad range of flow coefficients. A comparison with other competing turbines (viz, a twin Wells' turbine, a linked guide vane impulse turbine and a fixed guide vane impulse turbine) is done, based on actual measurements in the Indian wave energy plant. The results from the experiments are scaled to evaluate the design features of a 50 GWh wave energy plant. © 2010 Elsevier Ltd.

Renewable Energy

A twin unidirectional impulse turbine topology for OWC based wave energy plants - Experimental validation and scaling

It is difficult to make scaled down models that can produce electric power from waves based on the oscillating water column (OWC) principle in standard laboratory flumes. In this work, we show that precision measurements can be used to capture power signals from such a scaled down plant in a 600 mm wave flume. The measurement is difficult because the no load losses of the turbine motor exceed that generated from waves in a proposed twin unidirectional turbine topology. Twin 100 mm turbine models driven by brushless dc motors serve as the power module. Signals captured with 16-bit resolution are used to demonstrate the twin turbine concept. © 2009 IEEE.

2009 IEEE Intrumentation and Measurement Technology Conference, I2MTC 2009

Measurements for proof of concept validation of a twin unidirectional turbine wave energy plant

Experimental results from near shore bottom standing OWC based wave energy plants in Japan and India have now been available for about a decade. Historically the weakest link in the conversion efficiency of OWC based wave energy plants built so far has been the bidirectional turbine. This is possibly because a single turbine has been required to deliver power when the plant is exposed to random incident wave excitation varying by a factor of 10. A new topology that uses twin unidirectional turbines (which features a high efficiency spanning a broad range) is proposed. Using the Indian Wave Energy plant as a case study, it is shown that the power output from such a module considerably exceeds existing optimal configurations including those based on a fixed guide vane impulse turbine, linked guide vane impulse turbine or a Well's turbine. A wave to wire efficiency of the order of 50% over the incident range is shown to be feasible in a credible manner by showing the output at all stages of the conversion process. A frequency domain technique is used to compute the OWC efficiency and a time domain approach used for the power module with the turbine pressure being the pivotal variable. © 2008 Elsevier Ltd. All rights reserved.

A twin unidirectional impulse turbine topology for OWC based wave energy plants

Who's Who

Mundie, Douglas Stewart, (born 26 July 1952), Managing Director, Saltire Business Solutions Ltd, since 2004

International Journal of Marine Energy

Hydrodynamic optimization of the UGEN: Wave energy converter with U-shaped interior oscillating water column

Design of a 50 GWh wave energy plant

Journal	Proceedings of INDICON 2009 - An IEEE India Council Conference
Open Access	No