Exergy assessment and sustainability of a simple off-shore oscillating water column device.

This paper present a research on the performance efficiency and sustainability of an Oscillating Water Column (OWC) simple off-shore device, accounting for the influence of governing thermodynamic variables (moisture, temperature, pressure) in the compression/expansion polytropic process. The work proposes a simple off-shore OWC experimental set up as the basis of the study. The analysis takes into consideration both gas subsystems inside and outside the OWC, to achieve a better understanding of the conservative nature of entropy system variable, the net exchange balance, the effects on efficiency and exergy destruction, and the interpretation of the OWC as a thermodynamic engine. Results show that, within the context of the set up, moderate wave climate conditions contribute to a better efficiency of the device in terms of output power, providing with a low impact on exergy destruction and high sustainability in terms of renewability index. • The turbine acts like a restraint of the system. • The non-dimensional average pneumatic power output remains essentially constant. • The higher the relative depth the lower the relative available useful work obtained. • The higher the exergy efficiency, the higher the renewability index. • The exergy efficiency and the renewability index are higher in shallow water. [ABSTRACT FROM AUTHOR]