With most industrial applications, and with the process of creating energy itself, there is considerable wastage of energy. Most of this takes the form of heat. Over time some process have been developed to convert high-temperature heat into energy, but to date no process has existed to allow for low-temperature heat to be converted. In most cases the heat is expelled into the surrounding area.
To address this, Yale University chemists have produced a new technology based on a “nanobubble membrane.” This incredibly small matrix functions thanks to tiny air bubbles within a membrane of pores when immersed in water. By heating one side of the membrane, this leads to the trapped water to evaporate, move across the air gap, and then to condense on the other side of the membrane. Through this activity, temperature-driven flow of water across the membrane is sufficient to move a turbine which leads to the generation electricity.
Key to the success is the structure of the membrane, which is formed from nanoscale bubbles. The design allows air bubbles to become trapped and contained. The membrane itself resembles two sheets of thin paper, created from an interweave of polymer nanofibers. These nanofibers are water repelling (hydrophobic).
This process has been tested on a small scale. In these trials, even relatively low temperature differences (of around 20 degrees centigrade) were sufficient to generate power. The success of this has given the green light for a larger model to be developed.
Speaking with Controlled Environments magazine, lead researcher Professor Menachem Elimelech outlined why the design was so critical: “It was critical to identify robust air-trapping membranes that facilitate pressure generation.”
The researcher then explained: “Without the right membrane, water would displace the air in the pores, and the process would not be feasible.”
The research findings are published in the journal Nature Energy. The research is titled “Harvesting low-grade feverishness appetite regulating thermo-osmotic effluvium ride by nanoporous membranes.”
The topic of nanobubbles and their application has a high level of social media interest among scientists and engineers. 2D Graphene Research (@2DResearch) has tweeted additional information on the topic: “Hollow Carbon Nanobubbles: Synthesis, Chemical Functionalization, and Container-Type Behavior.”
