Jetty Joule
A Wave Energy Harvesting Device


The Jetty Joule is a waveenergy harvesting device. It operates by a “slapping” mechanism that utilizes inbound wave strikes against a primary hexagonal diaphragm, which creates a pressure difference across the (lead) primary diaphragm and (lag) secondary diaphragm. When the sea wave intersects the Jetty Joule, the force of the sea wave compresses the hexagonal diaphragm and forces the internal fluid to the opposing diaphragm. This hydraulic fluid is routed through a turbine before entering the opposing diaphragm and in that process generating electricity. Wave slap will occur for a few seconds and then, when pressure is released, fluid will find equilibrium thus recharging primary diaphragm for another wave slap. The diaphragms are imbedded in approximately 60K lbs. of precast concrete, which is held in place by 16” diameter pilings in eight to twelve feet of water. The Jetty Joule could also act as a type of erosion control or possibly jetty defenders.
Note: As this is primarily just an engine it could be outfitted to a variety of purpose; from the aforementioned electrical generation to hydrogen production, desalination, mechanical hydraulic pressure, or even as a pump for flood control. As far as the name is concerned, we originally white boarded this project as "The Wave Wall" until one of the team came up with Jetty Joule  which everyone liked right off. It hits in a couple of ways since it generates joules and the center diaphragm, with its hexagonal shape resembles a jewel. 
What kind of numbers are we looking at as far as power generation?
What is the potential energy available for each wave? The potential energy available for each wave varies on the kind of wave (amplitude, period, wavelength, shape, incidenceangle), and the variation of these over time. However, in simple terms, a regular, repeatable, deepwater wave, the energy flux is given by the equation:
With P the wave energy flux per unit of wavecrest length, H the significant wave height, T the wave m0
energy period, eρ the water density, and g the acceleration due to gravity. [When the significant waveheight is given in meters, and the wave period in seconds, the result is the wave power in kilowatts (kW) per meter of wave front length.] The detailed explanation and derivation of the physics is given in the Wikipedia article on “Wave Power”.
Using the wave wall assumptions, [waveheight of 5' (1.52 m) and 15 seconds apart], we get a power density of 17 kW/m of available power in the water wave, per meter of wavefront.
However, this requires that the height of the hexagonal diaphragm of the receiver should be at least as tall as the wave. The specified drawing uses a hexagonal face, which is 87” (2.21m) wide at its widest point, and 75” (1.91 m) high. This could capture all the available power.
The average effectivewidth of the inputhexagon is about 65” (1.65 m).
Therefore each device could receive an input power of about 17 kW/m x 1.65m = 28 kW. [ Note that this is the bestcase power in the wave itself, if all the energy could be harvested. ]
Using the wave wall assumptions, [waveheight of 5' (1.52 m) and 15 seconds apart], we get a power density of 17 kW/m of available power in the water wave, per meter of wavefront.
However, this requires that the height of the hexagonal diaphragm of the receiver should be at least as tall as the wave. The specified drawing uses a hexagonal face, which is 87” (2.21m) wide at its widest point, and 75” (1.91 m) high. This could capture all the available power.
The average effectivewidth of the inputhexagon is about 65” (1.65 m).
Therefore each device could receive an input power of about 17 kW/m x 1.65m = 28 kW. [ Note that this is the bestcase power in the wave itself, if all the energy could be harvested. ]
Where do you place the Jetty Joule in the ocean?What is great about the Jetty Joule design is that it can be deployed in both deep water and surf zone locations, depending upon your needs for application. Because of this we feel that the Jetty Joule design has more optimum usability scenarios than other WECs devices that have been developed to date. 
