Therefore, it seems to be able to have future the expectation by arranging Mighty Whale of the multiple unit, as a construction of calm sea area using Mighty Whale in the open sea tests area.
3.2 Seawater Drawing Technology
The ocean environment has been significantly deteriorated in the largely developed coastal zones, especially the enclosed sea. To improve the environment, special attention has been directed to the effective use of a renewable energy such as ocean energy. While, Recently, deep seawater also has been effectively used as resources. However, the construction cost for the pumping facility in land is high. To solve this problem, a pumping facility floating on the sea is The objective of this research is to develop not only a technology using the air-lift pump method which uses the compressed air produced by wave energy, but also seawater drawing technology using a simple and efficient facility.
The air-lift pump is one of a water drawing system making use of the force by rising air bubble when injecting compressed air into a water intake pipe. There is the reliability as a system, since there is no a driver which is mechanical for part in water on the air-lift system, and the maintenance is also easy, and it has advantage as a mechanism. Though in the current, drawing results of sea water by this system is little, the technology development of the possible air-lift system of drawing large quantities of sea water by a large diameter water intake pipe(5).
Figure 13 shows the experimental system for seawater drawing on Mighty Whale. This experimental system was designed on basis of the results of water tank experiment and the theoretical examine for an air-lift pump.
A flexible-pipe has been used for the water intake pipe of the experiment system that the inside diameter is 150 mm and the length is 30m from the mounting position to the point of the pipe in water. Compressed air for air-lift pump is supplied from 7.5kW air compressor has been installed on Mighty Whale. The nozzle positions for supplying compressed air are A, B and C in Figure 13.
Figure 14 shows the experimental results of the relation between air supply flow rate and quantity of drawing water on Mighty Whale. These results confirmed that the quantity of drawing water was 30l/sec (108m3/h) at air supply flow rate of 50m3/h. For this reason, we confirmed the effectiveness of the seawater drawing system using compressed air, and it is expected that this technology may be applied to seawater purifying and deep seawater drawing system.
3.3 Hybrid Power Generation system(6)
Mighty Whale will be possible to conjugate for coastal observation, aquatic resource monitoring and tests field for oceanographic observation equipment etc. as a platform that it is moored on offshore and is able to supply electric power from wave e energy.
The wave energy is one of the renewable energy, a weak point on which is to be available always not continuously. The capability on wave expected for supplying energy will always be kept lower whenever it may be fine and calm. Therefor, it is desired for such device to be designed so as to form so called hybrid system with other renewable energy generator combined each other thereon. In case of hybridization with wave energy generator, the power generation by means of solar energy and wind energy power generation may be considered to be the most promising process to be applied among all.
As for Mighty Whale, it seems to utilizing the slope of Mighty Whale that had not yet been occupied that it promises well adopting solar cell. The area of the slope on the prototype is 600m2 and is at angle of 7.6 degrees. The effective area for use among 600m2 of the slope was designed so as to be so large as equal to approximately 200m2 based upon a considerations of the effects due to the shadow formed during a period from 09:00 to 15:00 on the winter solstice when the Sun is at the lowest altitude. The feasible capacity of the solar cells which may be installed thereon the said 200m2 was obtained through calculated to be so high as equal to 20kW subject to 2 sets of the array comprised of 96 sheets of single crystal silicon solar cell panel with rated capacity of maximum output of 108.2 W.
