High-efficiency ballistic electrostatic generator using microdroplets.
The strong demand for renewable energy promotes research on novel methods and technologies for energy conversion. Microfluidic systems for energy conversion by streaming current are less known to the public, and the relatively low efficiencies previously obtained seemed to limit the further applications of such systems. Here we report a microdroplet-based electrostatic generator operating by an acceleration-deceleration cycle ('ballistic' conversion), and show that this principle enables both high efficiency and compact simple design. Water is accelerated by pumping it through a micropore to form a microjet breaking up into fast-moving charged droplets. Droplet kinetic energy is converted to electrical energy when the charged droplets decelerate in the electrical field that forms between membrane and target. We demonstrate conversion efficiencies of up to 48%, a power density of 160 kW m(-2) and both high- (20 kV) and low- (500 V) voltage operation. Besides offering striking new insights, the device potentially opens up new perspectives for low-cost and robust renewable energy conversion.
BIOS-Lab on a Chip Group, MESA+ Institute of Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Yanbo
Y
Xie
BIOS-Lab on a Chip Group, MESA+ Institute of Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Diederik
D
Bos
BIOS-Lab on a Chip Group, MESA+ Institute of Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Lennart J
LJ
de Vreede
BIOS-Lab on a Chip Group, MESA+ Institute of Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Hans L
HL
de Boer
Physics of Fluids Group, MESA+ Institute of Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Mark-Jan
MJ
van der Meulen
Physics of Fluids Group, MESA+ Institute of Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Michel
M
Versluis
BIOS-Lab on a Chip Group, MESA+ Institute of Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Ad J
AJ
Sprenkels
BIOS-Lab on a Chip Group, MESA+ Institute of Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Albert
A
van den Berg
BIOS-Lab on a Chip Group, MESA+ Institute of Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Jan C T
JC
Eijkel