Power Production through the use of Pressure Retarded Osmosis and Solar Distillation Ponds

EPA Grant Number: SU835687
Title: Power Production through the use of Pressure Retarded Osmosis and Solar Distillation Ponds
Investigators: Venkatadriagaram, Sundararajan
Institution: University of California - Riverside
EPA Project Officer: Page, Angela
Phase: I
Project Period: August 15, 2014 through August 14, 2015
Project Amount: $14,999
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2014) RFA Text |  Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Energy , P3 Challenge Area - Water , P3 Awards , Sustainability

Objective:

The goal of this project is to combine pressure retarded osmosis and solar distillation to generate power in a closed loop cycle.

Approach:

The proposed project uses salinity gradients and the heat capture from solar ponds to create a pressure difference from which energy may be extracted. The salinity gradient between fresh and salt water on opposite sides of a semi-permeable membrance creates an osmotic pressure that forces the fresh water to cross the membrane into the salt water. The increased flow on the salt water side will be used to drive a turbine from which electrical energy will be generated. The resulting diluted brine will be stored in a solar pond. Over time, a salinity gradient will develop, forming layers that restrict convection. The bottom, briny layer will retain thermal energy, where studies have shown temperatures can hold up to 100C for ponds 1m deep. Upon reaching a peak temperature, the water will be extracted and pumped back into the initial brine tank. Since the osmotic pressure increases with temperature, the system will be able to produce more energy than by just osmosis at ambient temperature.

The proposed method of energy extraction is ideally suited for warm areas of the world that is located near a body of water with high salinity and that also has a fresh-water stream available. The source of fresh-water could be a natural body of water or treated waste streams from a township that is being discharged to a sea or ocean.

Expected Results:

The proposed Phase I project involves the design and construction of a power plant that can generate about 100 W of energy from salinity gradients. The project will also identify environmental impacts such as land use, fresh water availability and increased salinity of water.

Supplemental Keywords:

renewable energy, alternative energy

Progress and Final Reports:

  • Final Report