@@ -32,6 +32,10 @@ Instead of the above, we propose a harvester that is still based on lift forces
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@@ -32,6 +32,10 @@ Instead of the above, we propose a harvester that is still based on lift forces
A small electrode at the upstream edge of the moving harvesting electrode is a control input. A small charge placed on this region will deflect the leading edge, causing the flow to peel the entire electrode apart. This does mechanical work against the electrostatic pressure, causing voltage on the moving electrode to rise (if charge is held constant. there are a number of operating modes possible, for instance constant voltage, constant charge, constant energy). This energy can be siphoned off the moving electrode and it can be oppositely charged to restart the cycle on the opposite edge of the cell. The control electrode is again charged to initiate the transition, and the harvesting electrode traverses back left.
A small electrode at the upstream edge of the moving harvesting electrode is a control input. A small charge placed on this region will deflect the leading edge, causing the flow to peel the entire electrode apart. This does mechanical work against the electrostatic pressure, causing voltage on the moving electrode to rise (if charge is held constant. there are a number of operating modes possible, for instance constant voltage, constant charge, constant energy). This energy can be siphoned off the moving electrode and it can be oppositely charged to restart the cycle on the opposite edge of the cell. The control electrode is again charged to initiate the transition, and the harvesting electrode traverses back left.
<imgsrc='img/peel-diagram.jpg'width=600px>
<imgsrc='img/bernouli-diagram.png'width=600px>
The flow speed and electrode length give upper and lower bounds on maximum possible operating frequencies. Using the conservative lower bound, we can start to get a picture of the power harvesting potential:
The flow speed and electrode length give upper and lower bounds on maximum possible operating frequencies. Using the conservative lower bound, we can start to get a picture of the power harvesting potential:
<imgsrc='img/power.png'width=600px>
<imgsrc='img/power.png'width=600px>
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@@ -46,6 +50,13 @@ These curves are truncated at dialectric breakdown voltages (assuming 17 V/um br
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@@ -46,6 +50,13 @@ These curves are truncated at dialectric breakdown voltages (assuming 17 V/um br
I'm envisioning this entire harvester array produced roll-to-roll from PET (dielectric) and aluminum foil (traces and electrodes). Because of the high voltages and low currents involved, the conductivity differences between copper and aluminum may be negligible. These materials are not only cheap but also recyclable.
I'm envisioning this entire harvester array produced roll-to-roll from PET (dielectric) and aluminum foil (traces and electrodes). Because of the high voltages and low currents involved, the conductivity differences between copper and aluminum may be negligible. These materials are not only cheap but also recyclable.
Making sure the peel starts from the primed leaded edge is an important consideration. As a first approximation, we can calculate the Bernouli forces from the flow constriction for a given electrode length and deflection angle:
