1. What type of protection is provided against rust, scaling and biofouling?
All the surfaces of both types of plants, except the solar panels, will be protected by applying special paint that uses Nano technology and resists the heat of boiling sea water for long periods of time. The paint doesn’t allow any attachment of salts especially at the hot zones. Biofouling is nonexistent because the painted surfaces are smooth to the molecular scale, and also doesn’t allow any attachment. The paints are resistant to ultra violate rays.
2. What is the structural resistance to waves and why do you need a wave breaker?
The criteria of the maximum size of waves that are allowed to hit the off-shore plant are not governed by the structural strength of the plant. Rather, it is limited to the splash that the wave could cause. For this reason, the allowable limit of the wave size is two feet. This limitation requires that a wave breaker be provided to protect the plant from the waves, or locating the plant in a bay area that could naturally provide the required protection.
3. How long can plants last?
It is assumed that plants will last 40 years. The lifetime of plants is related to the disintegration of parts and materials due to high temperatures, ultra violate waves, wear and tear of the outer surfaces or protecting covers of surfaces. Therefore, it is very important to know what type of material and/or protective cover is used for the different components of the plants.
Copper pipes can last for more than 70 years. Polyurethane can last for more than 50 years. Flexi glass can last for more than 40 years, and can easily be replaced without affecting the function of the plant.
4. What is the hurricane /tornado force resistance of the plant?
a. On-shore plants: There is not much concern about damages caused by hurricane/tornadoes, except for flying objects that might hit the top glass. Otherwise the different parts are well connected and can withstand the force of a hurricane/tornado.
b. Off-shore plants: Hurricanes could cause serious damages to the flexi glass. Therefore, it is important to reinforce it by putting ribs on the underside of the glass to resist the hurricane’s pulling force. Also the plant should be protected from waves by using wave breakers.
5. How long do solar panels last and how do they stay clean?
The solar panels are made of polyvinyl material that can transmit 96% of sun light and has a lifetime of over 25 years. Distilled water, which doesn’t leave deposits, washes the upper surface of the glass approximately twice a day.
6. What is the floating level of an off-shore plant?
The plants float up and down in accordance with the sea level. The water level inside the plant and within the cells may go up and down too, for the following reasons:
a. Before operation, the surface water level inside the plant matches the sea outside the plant. However, after the start of the plant, the water level changes with the change in the temperature of the column of water within the plant. The water level within the plant will range between 15 and 25 cm above sea level depending on the season. The average temperature within the plant could reach 70ºC in summer while it could go down to 50ºC in winter.
b. The water level could rise inside the plant because of the amount of negative pressure applied to the blown air out of the system. This amount could reach 10 cm during normal operations. But, the amount of water produced and the negative pressure applied could generate a rise of water inside the plant up to 20 cm. The total variation available according to the design and total operable height of the stem of the pedestals is 80 cm.
7. How thick are the solar panels?
The thickness of the flexi glass range is 8 mm.
8. How is fresh water conveyed to the shore line?
After the distilled water is collected in the floating reservoirs, it is pumped to the shore line using submersible pumps. This is shown as the floating pumping station in drawing #1.
9. What is the minimum area required for plants?
On-shore plants: 18 m².
Off-shore plants: 2400 m².
Note: By area we mean the total surface area of the water in the cells that is subjected to evaporation.
10. How do you build an off-shore plant?
Parts of the assembly could be performed on the shore line and completed by pulling it into the water as it is built. Or, it could be built on the shore over inflatable pipes and gradually pulled out into deeper water as the construction proceeds.
11. What materials are used to build plants?
a. The body of the tank is made of steel plates.
b. The heat insulation barrier for the On-shore plant is made of polyurethane.
c. All the pipes inside the plant are made of copper except the brine pipes which are made of HDPE
d. The pipes outside on- and off-shore plants are made of HDPE.
e. The solar cell covers are made of Flexi glass.
f. The body of the pedestals and the heat insulation barrier are made of polyurethane.
g. The trees and first layer of network of pipes are made of copper pipes.
h. The lowest layer of network of pipes is made of HDPE pipes.
12. How long does it take to manufacture parts and construct a plant?
Three months are required to completely manufacture the components of the On-shore pilot plant, and four months for construction.
At least six months are required to manufacture parts for off-shore plants and an additional nine months for construction.
13. What water depth is required under the heat insulation barrier?
16 Feet or ~ 5 meters
14. What is the total height above sea level for the off-shore plant?
The plant is five feet above water level and 52 feet submerged with a 10 foot clearance above the sea bed as a minimum at the low tide. Therefore, it is required to have a minimum total depth of water at the specific location at low tide equivalent to 62 feet or ~ 19 meters.
15. What type of wave breaker is required and what wave height can the plant sustain?
We recommend using a floating type when the water depth is far more than 62 feet at the low tide. Waves should not exceed two feet in order to limit the splash of water over the exterior panels and eliminate damages to the plant structure.
16. What is the minimum production capacity for plant efficiency?
On-shore: 18 m²; Productivity = 230 m³/ day
Off-shore: 2304 m²; Productivity = 30,000 m³/ day
17. What climate conditions can make the plant inefficient?
The plant is efficient between + 37th parallel. Beyond that, the efficiency will gradually decrease.
18. What heat gradient affects the water outside the off-shore plant’s heat insulation barrier?
The natural heat gradient of the sea will not be affected at all because the rate of heat loss is minimal, about 2% of solar energy available per day. Also, any heat loss that takes place will warm the film of water adjacent to the HIB, and this warm film of water will rise up and spread out over the sea surface.
19. Can you check inside an On-shore plant without shutting it down?
20. How do you connect the distillation system and floating pumping station to the shore line?
The first two structures are connected through flexible pipes that are kept in position relative to the sea bed through mooring cables. The same applies for the pipes from the floating pumping station to the shore line.
21. How do you position the system relative to the seabed?
Through a system of mooring cables and floats.
22. How much heat is lost through condensation?
For Off-shore the maximum is 5% and for On-shore could be between 12% - 15%.
23. What is the percentage of solar energy that penetrates the solar panel?
24. What is the heat gradient on the vertical section of the body of water under the cells?
After operating the system for four months, the heat gradient will be 7ºC per meter of depth.
25. How much electrical power is needed to run the plants?
On-shore: For each 10 square meters of water surface area, the amount of electrical power required is < 6 KWh per day.
Off-shore: For each 1000 square meters of water surface area, the amount of electrical power required is < 5 kWh (for air blower) + 65 kWh for pumping out the distilled water to the shore line. Total = 70 kWh per day.
26. What kind of maintenance is required?
Since there are no moving parts in the plants, the only maintenance required is for the auxiliaries, i.e. the air blowers, pumps, floating pumping station and the instrumentation.
27. What is the quantity of blown out air, and how much humidity is lost?
Every one cubic meter of air that is blown out will produce 130 liters of distilled water. The amount of air is 10% of the total air circulated in the system. The amount of humidity in the blown out air ranges between 12 to 17 grams per cubic meter.