Comparison between pressure retarded osmosis model using batch and continuous water supply sources

Abstract

Pressure retarded osmosis (PRO) is a novel renewable energy technology that generates electricity from two water sources. Due to the osmotic pressure difference, freshwater permeates across a membrane to the other side, where the high-pressure seawater flows and drives a turbine to generate power. Many mathematic models have been proposed to evaluate the performance of a PRO. However, it was found that most performance of the PRO that have been reported were performance by using freshwater with limited supply (batch) in the model. It is not accurate as, in practice, the supply of freshwater occurs in a continuous manner. In this work, the influence of batch and continuous supply of fresh water on the performance of PRO was demonstrated. The effect of flow direction, i.e., concurrent and counter-current flows, was also examined. The model simulation was performed by using MATLLAB program, and the performance of PRO is expressed in terms of average power density. The results revealed that the batch and continuous supplies of freshwater had a strong impact on the performance of the PRO. However, the performance of concurrent and counter-current flow were not significantly different.