Vierailijat

sunnuntai 6. maaliskuuta 2016

Waveroller - electricity from Ocean wave's

23.march.2014 Sunday

I just make this English version from an earlier Finnish one published on March 2014.

Just arrived from Portugal and finished my last report about the work done there. And tough that as well I can write something in my blog.

Some words about our company AW-Energy
AW-Energy Oy has wave energy converter name Waveroller installed in Peniche Portugal. It has been several times connected on national grid. This device really makes elecrtricity from Ocean wave movements and it works very well. How ever this device is still a demo unit and need continually improvements and maintaining.

From here I come on the scene. Not to do improvements, but to place this Waveroller on sea bottom and to reflot it when come necessary together with trained local divers. As well a lot of different things around naval operations.
Waveroller just ready to the first succesfull submerge test in summer 2012.

3 wing Waveroller unit. 
The morning mist creates mysterious athmosphere, even Portuguese media noticed that in 2012

My wife, my daughter and my son were watching Waveroller test submerging operation inside Peniche harbour 2012



Back to 2014
Last winter has been one of the most stormy and violent for living memory in Peniche, there are still a lot of storm damages wayting to be fixed. One strange thing was all sand seems to disappeared form beaches. Just beside our site one small fishing village all sand has totally gone. Now only rocky bottom, that does not aloud to pull boats over. Fishermans are trying to bring little sand by small truck's just to be able to pull their boats back to sea, like tiny sand trail. This sand thing is not promising to our job.

Waveroller has been in shipyard just holding there new wing, that should have much better wave capacity ability to convert into electricity . This is like in Formula 1, all the time small adjusting in order to get more power.

Because the hard wind we haven´t been able to go to sea before, that is not surprising anybody during winter time. Now for long time we got so called "weather window" that gives to us few days for operate on the sea. We need to dig up the sea cable under the sand, check the mooring and bring sea marks to shore for service. Our worst nightmare is some 2,5 meter sand on top of the cable. Our operational fleet is 2 rubberboat and one 15m fishing boat for carrying the compressor and bringing sea marks to harbour.
From the rubberboats we are operating with two "Mammuth pump" or "Air lift pump" with which we have removed the sand that was covering the sea cable.

The suction part need handles for better maneuver and a cross in front to prevent  that any bigger part can't get inside.
There is a valve for divers, so they can  adjust the sucking power.

Our "Mammuth pump" is 100mm diameter. Can be much bigger, but then it is not so movable. And moving some 2m sand from top of the sea cable or chain ends is more than enough. System works so we pump air to the lowest part of the "Mammuth", then air bubbles start to rise up to surface and that makes huge flow. This moves a lot of land, but works only underwater.
With this very simple method we are performing underwater sand movement. Meaning moving sand from top of the cable, chains, etc.


Metal suction part is some less that 1m long, connected some 15m long fexible hose.
Also connected 2 x 4kg extra diving weight, this instrument is pulling like wild horse.

I need to tell something about this "Mammuth pump".
We went to the sea on Friday morning. Divers start suck the sand, first from the cable site.
If you let it suck too fast the sand bed. It gets stuck - no water flow and the hose gets fast filled with air!! When the hose has only air inside,  creates a huge lifting power and soon the hole "Mammuth" is turning like a snake just break away from your fingers up to surface.
So far this is the easy part, but a warning sign. Now when this especially heavy suckin part reaches surface and makes so called "burb", meaning letting all air come out in seconds. After that there is nothing that keep it floating and it comes down like anstopped anchor. This is the point when this game start come a little dangerous. Nobody should wait on the bottom hands wide open when the heavy anchor is coming, that may hurt when hit you.
Therefore the working spot is not a waiting place when this "burb" happens. Diver should move to another safer place, for a moment. Because of that is good to use divers that knows what they are doing, or at least somebody must be in knowledge of what is ongoing.

I mentioned earlier that sand had disappeared from beaches to somewhere, unfortunatly that somewhere seems to be our working spot. Our device is some 600m from the beach in 13m waterdepth. Now after digging some 5m crater, some 10 meter wide. We were just able reach the cable, but not enough to clear it and able to pull it out. And next day it was again mostly covered by sand, lucky us, not totally. Day after we continue and were able to connect 2Ton lifting bags on the cable end. Now with liftingbags we managed to pull the cable out from the sea bottom some 30m. After that we left it on the bottom waiting the maintaining and new connector part to be change. It was difficult job, local divers made good tuff job and later in dinner you were able to see how tired they were.


2Tonn lifitngbags 2units, ready for use.

Filling diving bottles 8 at the time.

In Saturday we start to remove our marking buoys for harbour. There was a lot of goodlooking big mussels. Buoys itself are fiberglass and captain of the fishing boat collected some 30-40kg also divers were collecting them like crazys. I have heard that mussels groving up close of metall makes them toxic and can paralyzed the eater. So I leave them before better information is available.

Local diver using Finnish tailor made Loitokari drysuit. Cleaning the chain and chakle for disconnecting.
Small and handy tender Zodiac MK V + 2 x, 2Ton "totalclosed" liftingbags. 

Using this liftingbags need to be extremelly carefull. This bags had bad habit when they are lifting something from the sea bottom. The sand bottom has very strong "bottom suck" that keeps objects stuck there. When pulling up something with liftingbags, in some point this "bottom suck" finally gives up. What happens, the liftingbags are coming up like rocket with connected object. All this happens suddenly, and when it happens, there is always several tonn lifting power on. It can not be stopped until on surface.
If a diver get along with this rocket rise, the air in his lungs get expanding super fast and diver can get seriously injured.
So need to work carefully also with liftingbags.

Our navigation marking buoys had hundred kilos of mussels, One buoy already cleaned and other wayting clean-up.

Mussels grove up really huge sizes here in Portugal. In one year they reach 10-15cm size. Also it is said that in Portugal is European best waters to grow up the purest mussels. I can tell that they are good, but dont know if this is true.

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