NSF award supports research on sustainable energy production

By Jennifer Swales
April 29, 2015

UNIVERSITY PARK, Pa. – Bruce Logan, Evan Pugh Professor and Kappe Professor of Environmental Engineering, and Christopher Gorski, assistant professor of civil and environmental engineering,  received a National Science Foundation EAGER award to fund their research on technologies that generate and store electrical energy from waste heat using salinity gradients.

NSF Early-concept Grants for Exploratory Research (EAGER) funding is used to support exploratory work in its early stages on untested, but potentially transformative, research ideas or approaches.

The researchers received a $130,000 grant for the one-year project, which began April 1.

The goal of the project,“Enhanced Electricity Production from Engineered Salinity Gradients using Capacitive Mixing,” is to take a new approach to energy production and storage using a process called CapMix -- captive and pseudo-captive mixing.

“What we propose is a process that will capture electrical energy out of a chemical in water,” Logan said. “Then we can remove that chemical out of the water using waste heat.”

Using the CapMix process, the researchers hope to develop and advance new methods for energy production using primarily only water and simple and renewable materials.

Currently, several technologies are being explored to capture electrical energy from salinity gradients. These gradients may exist naturally in such things as seawater and river water or be engineered by using, for example, waste heat and thermolytic salts.

CapMix is one of the newest methods. In this approach, capacitive and pseudo-capacitive electrodes are alternately exposed to solutions having high and low salt concentrations.

The researchers will be using ammonium bicarbonate as the salty solution and will also experiment with ammonia.

Both ammonia and ammonium bicarbonate can be driven out of water by heat, Logan said. “We hope to use that heat energy as a way to create, essentially, batteries.”

Unlike other technologies, CapMix has a critical advantage because it does not require membrane materials such as reverse osmosis membranes or pressure retarded membranes, which are often prohibitively expensive. The problem with current CapMix methods, however, is that they tend to produce lower power densities than these membrane-based processes.

Logan and Gorski hope to change that. In their system, CapMix processes will use inexpensive and activated carbon and binders, in some cases avoiding the need for costly membranes. Even when a membrane is needed, it will be minimal.

If successful, the technology could produce two results simultaneously while past technologies have only been able to produce one.

“Previous heat recovery technologies only transform heat energy into electricity,” Logan said. “Then there are energy storage systems that cannot transform energy. What makes this a really unique approach is the potential to do both.”

Logan said this technology could improve energy efficiency at power plants and extract energy from waste heat for later use.

“Nobody has tried to create battery-like reactions with these solutions before, so we have to really sift through the chemistry,” Logan said. “… But the potential is out there.”

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Last Updated April 30, 2015