Chennai: The twenty-first century is increasingly characterized by demand for energy. Coupled with dwindling fossil fuel reserves and increasing awareness of pollution issues, there is now an urgent need to develop renewable energy options. In what can be perceived as a solution to this, researchers at Indian Institute of Technology Madras and National Institute of Ocean Technology (NIOT) are working towards developing better turbines that can harness the power of ocean waves to generate electricity.
Their most recent studies on turbine-chamber coupling have been published in the reputed peer-reviewed International Journal of Energy Research.
The Research Team comprises of Mr Aravind George, Ms Suchithra Ravikular, Mr R. Ananthnarayan, and Dr Abdus Samad from the Department of Ocean Engineering, IIT Madras and scientists Mr Prasad Dudhgaonkar, Mr Biren Patnaik, and Dr Purnima Jalihal from NIOT. Although one of the biggest storehouses of energy, ocean energy is difficult to harness as it is unsteady. Thus, efficient recovery of energy from waves depends on improving the performance of devices that convert inconsistent wave movement to electricity.
“Wave-energy harvesting turbines capture the energy of the periodic up-down motion of ocean waves through a device called Oscillating Water Column. One such turbine called impulse turbine is connected to a generator which converts the mechanical energy into electrical energy. The turbine uses the energy of a high-velocity air jet created by the waves in the device.”, says Dr Abdus Samad
The aerodynamic performance of the turbine plays a major role in the wave-to-wire conversion efficiency. The coupling between the hydrodynamic process of the wave energy absorption and the turbine’s aerodynamic process is affected by the interplay between the pressure in the oscillating water column and the airflow rate through the turbine.
This interplay is called the damping effect. The variability of waves induces varying turbine speed, which in turn affects damping. Dr Abdus Samad and his team have analyzed the running characteristics of a turbine connected to an oscillatory airflow test rig and subjected to varying rotational speeds.