Pneumatic

Pneumatically Stabilized platforms

Advantages claimed

	It uses air movement to reduce wave loads and distribute them throughout the platform
	It extracts energy from ocean waves that can be used to make electricity.
	It attenuates the waves leaving a calm surface that permits adjacent ship berthing, or in our case kingdom boats and islands to have a patch of calm.
	It has a relatively shallow draft and low adjustable freeboard.
	Lower cost of construction than solid forms as well as more stable.
	Allows lower larger cheaper land development of islands.

So what are we talking about

The platform is made of a large number of cylinders, or tubes sealed at one end, open to the ocean at the bottom. Air is allowed to pass from some cylinders to neighboring ones having a damper effect on the waves. In shallow water or protected water, for example, the cylinders can be quite wide and not very deep while in deep ocean they are far deeper and narrower. Additional buoyant material would be between the cylinders.

As air moves from one cylinder to another it can be used to create electricity.

Proposals usually involve creating sections, similar to the one shown above, that are floated into place and joined up, forming any size you want, a surface is then added.

A design based on this was proposed for an ocean based airport for San Diage and you can find information and an artists impression at http://www.floatinc.com/WhatItIs.html, a similar design has been proposed for San Francisco bay.

Pneumatically Stabilized Platform (PSP) and energy production

The Oscillating Water Column (OWC)

The platform is intrinsically an OWC device. The oscillating water columns and the movement of pressurized air among its perimeter cylinders are its means of attenuating the waves and isolating the platform from the wave induced forces.

	The whole structure is made of concrete, most likely Ferrocement.
	It is comprised of modules which are less costly to build and put in place.
	It can be located offshore.
	Waves lose energy as they approach the shore. Waves captured in deeper water will have much more of their energy available to harvest.
	Most deep water capture devices permit a significant portion of the wave to pass through if required. The demonstrated wave attenuation properties of the PSP indicate that it will capture a larger percentage of each wave's energy.
	Manifolding the cylinders and rectifying the air flow will allow the use of fewer, simpler, less costly, and more efficient unidirectional airflow turbines.
	The PSP was designed for specific uses such as floating breakwaters, harbors, airports, etc. This "dual use" capability has always been considered to be important to the economics of the PSP's energy production. However, recent calculations indicate that where the wave resource is sufficient, economies of scale may enable the PSP to be competitive even where additional uses are limited.

A test system is to be built in the USA (California we think), principally to harvest energy from waves.

The Louisiana port commission are also working on a multi purpose floating platform of a similar design in the Gulf of Mexico.

Our 'brains' say

The wave dissipation is achieved by allowing air to pass from some cylinders to some others, however sufficient have to be left unconnected to keep the platform level. In the case of cylinders infill between them can provide some additional buoyancy, reducing the depth needed.

By adding more compressed air or allowing some air to be released the height of the island can be adjusted slightly. Air under the platform that is trapped will be at a greater pressure than the atmosphere when at rest, and during parts of the wave cycle will increase greater and reduce.

If the wave is too large for the platform design the risk is that a gap will form under the center at some point and air can escape. A second risk occurs when too many chambers are interconnected in that if air escapes, for example through a collision or faulty manifold or piping then the buoyancy will be reduced. We feel that the outer row or two of cylinders, most likely to become damaged should form a separate sub system from an interconnection system to the bulk in the center, and that every cylinder should be able to be isolated from the air exchange system.

We suggest cone or cup shapes instead of tubes with the gaps between sealed so conventional buoyancy plus the interconnections being organized into a number of separate systems so that if one part fails the effect is minimal. We also suggest that any island should have sufficient other buoyancy and reserve buoyancy so that if something should happen to cause the loss of the air the island will stay afloat and balanced.

Some think that a box structure should form the platform structure and that this should include air pressure rooms, through which all manifolds and piping passes, so that air escapes can be detected by air pressure changes within rooms and to stop the loss of buoyancy. The arrangement should also contain break out valves so that should an island break in two at any join then the broken pipes will automatically seal off.

Some designs we have seen present platforms being floated together and clipped at the surface, giving a week joining point where movement is likely. We would be happier if the understructure was continued and the under structure was joined to form a solid structure. As most of these structures are suggested to be Ferrocement then this should not produce any difficulty. Given this the honeycombed effect would be strong once formed, especially if the deck level formed a box structure.

As far as power generating capacity goes, within the walls there may not be very much in the form of waves, the outer walls and first line of islands having smoothed out most, however we do expect there to be some rise and fall, but it is difficult due to the long wave length of these to predict how much power could be produced. We see that some power could be produced. Pneumatic platform sections as the outer parts of islands we see may produce some power from the disturbance created by passing water transport, but this would be proportional to how busy the traffic was. It would also even out the edge stresses caused by this disturbance.

It is likely that rather than having separate generators between all cells as some suggest, a valve system automatically operating by air pressure could allow air from a group of cells to leave, go via a common manifold, through a turbine, and via a common input manifold to cells with a negative pressure.

It may become necessary over time to both be able to get inside the cones for maintenance and to be able to change the air

There are very many opportunities to investigate these areas further, and how they can be combined with others.

Applications within the floating kingdom

Potentially there are many, including the walls and island designs.

Sea defenses

One idea that is being considered is that of a multi stage sea defense, where the outer ocean defenses dissipate some of the waves and allow some of the wave to pass through to an intermediate level, which absorbs more, to a first ring of islands that smoothes it completely. The largest problem in this design is holding everything in place in heavy seas.

Another idea suggested would be a pointed nose that deflects the worst of the high waves and uses a number of platforms that are connected into a triangle shape where the outer ones use some energy passing through to the next layer and so on, so that at the back of the triangle all wave energy has been used and harvested. Side walls would have intermediate wave capability and an inner ring of islands would smooth it completely.

The viability of different approaches comes down to cost against return. As most of the time in our chosen location wave height is not great a design involving harvesting large waves would only prove advantageous in high seas. Some have suggested that this system could be developed so that the energy produced was used to hold the island in place and therefore more power when the wind was higher and waves greater would work out well. It is suggested that the protective nose together with wings on walls could hold the kingdom in position in all conditions.

In practice we see the advantage of combinations of technologies and see this technology being able to be used as part of a system rather than as it being a choice of one technology or another. We are always concerned that any system should it fail for any reason will still continue to do its function and be repairable.

As a building platform for islands.

Large platforms using pneumatic sections connected together can be very small in comparison to other means as the power dissipation, removes much of the need for strength to bridge waves.

This means you can have within protected water a very low cost, and quick to assemble means of producing a base to build on.

Looking at the risks. The size and shape of the cylinders are different for sheltered water, as opposed to open ocean, so in the worst case situation of the kingdom breaking up, while solid islands would survive, the risks on low pneumatic platforms would be greater. However the larger the platform the more likely it would survive, so very large islands may have ocean go over some sections of it but would most likely survive. Built with intermediate cylinders would cost more in island development costs but could then survive outside the kingdom. See also section above within the 'our brains say'

In sheltered water the cylinders can be shallow, perhaps only 3 feet deep, and large over perhaps 12 feet, looking more like tanks than tubes, while in the ocean they might be very tall and much thinner, even spaced out so that waves can pass through between them. For larger islands while the outer modules may have tube shaped tanks for strength, inner ones could have a far simpler divider structure, producing squares or rectangles.

As designs evolve we are expecting to see more designs of mixed technologies perhaps a conventional section surrounded by pneumatic platform sections as a single structure or pneumatic platforms of different dimensions and types being built into a single structure. The most obvious would be where the outer sections are more like ocean platform sections going down to inland water designs towards the center of the island, therefore the outer sections provide sea protection and first level smoothing, and the central section is more about providing buoyancy for the load and spreading the load, without the structure having to be excessively large.

Very little information can be found on this area on the internet, however as we identify more contacts we will add them below.