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

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.

[1]  Manabu Takao,et al.  Performance estimation of bi-directional turbines in wave energy plants , 2007 .

[2]  R Curran,et al.  Design synthesis of oscillating water column wave energy converters: Performance matching , 1997 .

[3]  R. Curran,et al.  Aerodynamic conversion of ocean power from wave to wire , 1998 .

[4]  A. Thakker,et al.  Experimental studies on effect of guide vane shape on performance of impulse turbine for wave energy conversion , 2005 .

[5]  C. Josset,et al.  A time-domain numerical simulator for oscillating water column wave power plants , 2007 .

[6]  A. Thakker,et al.  Effects of turbine damping on performance of an impulse turbine for wave energy conversion under different sea conditions using numerical simulation techniques , 2004 .

[7]  Per Magne Lillebekken,et al.  Lineår modelling of oscillating water columns including viscous loss , 1996 .

[8]  A. Clément,et al.  Wave energy in Europe: current status and perspectives , 2002 .

[9]  Paulo Alexandre Justino,et al.  OWC wave energy devices with air flow control , 1999 .

[10]  Manabu Takao,et al.  Performance of an Impulse Turbine Based Wave Energy Plant , 1998 .

[11]  D. Evans,et al.  HYDRODYNAMIC CHARACTERISTICS OF AN OSCILLATING WATER COLUMN DEVICE , 1995 .

[12]  Toshiaki Setoguchi,et al.  Impulse Turbine with Self-Pitch-Controlled Guide Vanes for Wave Power Conversion (Guide Vanes Connected by Link Motion) , 1995 .

[13]  António Sarmento,et al.  Overall-efficiency optimisation in OWC devices , 2003 .

[14]  Manabu Takao,et al.  A review of impulse turbines for wave energy conversion , 2001 .

[15]  Purnima Jalihal,et al.  Wave powered desalination system , 2004 .

[16]  Luís M.C. Gato,et al.  Aerodynamics of the wells turbine , 1988 .

[17]  António F.O. Falcão.  Stochastic modelling in wave power-equipment optimization: maximum energy production versus maximum profit , 2004 .

[18]  Martin Greenhow,et al.  Optimal heave motion of some axisymmetric wave energy devices in sinusoidal waves , 1997 .

[19]  Luís M.C. Gato,et al.  The energy conversion performance of several types of Wells turbine designs , 1997 .

[20]  Srinivasan Raghunathan,et al.  Performance of the Wells self-rectifying air turbine , 1985 .

[21]  Manabu Takao,et al.  Current status of self rectifying air turbines for wave energy conversion , 2006 .

[22]  Toshiaki Setoguchi,et al.  Self-Rectifying Turbines For Wave Energy Conversion , 1992 .

[23]  Yukimaru Shimizu,et al.  Studies on the Shore-Fixed Air Chamber for Wave Power Generation. Pressure and Flow Direction Control for a Turbine with a Swaying Valve. , 1995 .

[24]  Paolo Boccotti,et al.  Comparison between a U-OWC and a conventional OWC , 2007 .

[25]  Manabu Takao,et al.  Impulse Turbine For Wave Power Conversion With Air Flow Rectification System , 2001 .