Jumping-droplet electrostatic energy harvesting

Journal Article · Thu Jul 10 00:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4886798· OSTI ID:1387183

Miljkovic, Nenad ^[1]; Preston, Daniel J. ^[1]; Enright, Ryan ^[2]; Wang, Evelyn N. ^[1]

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1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Mechanical Engineering
2. Bell Labs Ireland, Dublin (Ireland). Thermal Management Research Group, Efficient Energy Transfer (gET) Dept.

Micro- and nanoscale wetting phenomena have been an active area of research due to its potential for improving engineered system performance involving phase change. With the recent advancements in micro/nanofabrication techniques, structured surfaces can now be designed to allow condensing coalesced droplets to spontaneously jump off the surface due to the conversion of excess surface energy into kinetic energy. In addition to being removed at micrometric length scales (~10 μm), jumping water droplets also attain a positive electrostatic charge (~10–100 fC) from the hydrophobic coating/condensate interaction. In this work, we take advantage of this droplet charging to demonstrate jumping-droplet electrostatic energy harvesting. The charged droplets jump between superhydrophobic copper oxide and hydrophilic copper surfaces to create an electrostatic potential and generate power during formation of atmospheric dew. We demonstrated power densities of ~15 pW/cm², which, in the near term, can be improved to ~1 $$μ$$W/cm². This work demonstrates a surface engineered platform that promises to be low cost and scalable for atmospheric energy harvesting and electric power generation.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0001299; FG02-09ER46577
• OSTI ID: 1387183
• Journal Information: Applied Physics Letters, Vol. 105, Issue 1; Related Information: S3TEC partners with Massachusetts Institute of Technology (lead); Boston College; Oak Ridge National Laboratory; Rensselaer Polytechnic Institute; ISSN 0003-6951
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

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