How We Can Diminish the Possibility of Water Wars

Courtesy Wikipedia

There does not seem to be the urgency about upcoming water shortages that the situation warrants. The evidence for a foreboding future, though, are all around us. Just look at Cape Town, Africa. Their draconian emergency measures include restricting toilet flushing to once a day unless using grey water or rain water. Municipal drinking water cannot be used for kiddie play pools, water fountains, any outdoor water feature, hosing down paved surfaces, or car washing. In March of 2018, the Climate Reality Project published an articles examining how Los Angeles, Salt Lake City, and Miami may not be far behind Cape Town on water problems. In India, the demand for water by 2030 will be twice the available supply. It will affect 600 million people. 

The major constriction for producing food for a burgeoning population is water - not land. According to the International Food Policy Research Institute, nearly 5 billion people, about half of global grain production, and 45% of the GPD ($63 trillion dollars) will be at risk due to lack of water with current consumption practices. Eighteen countries; including the big-three grain producers China, India, and the U.S.; are now over-pumping their aquifers. For 20 years Saudi Arabia was self-sufficient in growing wheat. They have nearly exhausted their aquifer and will soon quit growing wheat. Recent droughts in California and Texas seem bad but there is evidence that a major portion of the Southwest U.S. underwent a 10-year drought with hardly a drop of rain several hundred years ago. That was before climate change. An inexpensive, alternative water source is needed. There is a way. This is how it will work.

Paper bags take 5 X the water to make and 7 X the fuel to transport than plastic bags  

There is a lot of talk about the oceans warming up. They are mainly referring to the top layer, the Epipelagic or Sunlight Zone, of the oceans, which is warming at a rate of about 0.2 degrees Fahrenheit every decade since the 1800s. If you go down about 2,500 feet, though, where sunlight never reaches, the temperature drops to about 46 degrees Fahrenheit. It gets colder as you go deeper until it is between 32 and 37 degrees Fahrenheit. Ninety percent of the ocean is 46 degrees Fahrenheit or colder. 

This means there is a large thermal gradient for about forty percent of the world between this cold ocean water and the Sunlight Zone and tropospheric, or lower, layer of the atmosphere. This thermal gradient can be exploited for the production of huge amounts of water.

New desalination plants require a lot of pressure to force ocean water through reverse osmosis filters. Old style plants heated up the water to vaporize it, then condense it. These processes use a lot of power, an ongoing overhead cost. The filters themselves are also expensive. With both processes you wind up dumping much saltier water back into the ocean. The other type of water extractor creates, through standard refrigeration technology, a cold surface for humidity in the air to condense upon. Think how much it costs to run an air conditioner in the summer in a hot climate. The same problem exists with these types of water production units.  

It costs $4000 to recycle ton of plastic bags worth $500 on open market. 

What we need to do is work with nature to produce water. Take the cold ocean water, run it through a heat exchanger at the surface of the ocean while at the same time forcing warm, humid air through that heat exchanger with fans. The humidity in the air condenses out on the cold surface of the coils containing seawater. You see this principle every time you go to a restaurant and order a cold beverage in a glass. Beads of water form on the glass and run down the sides. This is the simplicity of the process we are talking about. 

The electricity used is for simple water pumps and air fans, not compressors having to produce hundreds of pounds of pressure. Comparatively cheap initial cost and every-day energy consumption. They could be matched to solar panel / lithium ion battery combos that would keep them running night and day. These water production units can be scaled from tiny to gargantuan. 

So where are these things going to be located? Anywhere along the coast about 40 degrees above and below the equator. There is an alternative that will be common in the future. These units will be designed to coexist with offshore wind farms. It is a simple thing to integrate these devices into the support towers for windmills. Along with the cables collecting electricity will be the pipes collecting water. 

Wind farms are currently located near shore, anchored in 200 feet depth or shallower. With the advent of floating windmills (first ones installed off Norway), this depth can be increased to 2,600 feet with direct access to cold ocean water. If energy developers are smart they will pick up on this opportunity and incorporate the water production units from the beginning. 

Plastic bags are made from ethane, a part of natural gas burned as waste before they started making plastic bags. 

You might be asking how much water are we talking about. An experiment was done using copper coils, ice chests of cold water, and a fan. With an average air velocity of 4 mph, humidity of 66 percent, 87 degree F. air temperature, and 47 degree F. water temperature the production was .0191 gallons of water per hour for every square foot of coil. Doesn’t sound like much, but lets apply it somewhere. 

We will use Los Angeles as a case study because it is strapped for water, and I happen to have the year round average weather for LA; 65.4 degrees F. air temperature and 71 percent humidity. An offshore wind farm is being installed near LA. There will be 50 turbines 500 feet in diameter. They will be the new floating type in 2,500 feet of water where the water temperature at the bottom is 46 degrees F. Fans will force ambient air through the heat exchanger coils at 16 mph. Mainly because of the increased air volume, the production factor goes up to .062 gallons of water per hour per square foot of coil surface area. 

Plastic grocery bags prefer this as their second career. 

The coil will encircle the support tower of the windmill. Looking at it from above, it only has a square footage of about 950 square feet, the size of a small house. The coils are 45 feet long. They are 1” diameter tubes with (7) 7/8” high fins attached axially to increase the surface area of the coil. Examining the pictures you get a sense of what this would look like in comparison to the windmill because it was drawn to scale. Though it looks small, the total surface area is about 202,000 square feet, which means this unit produces about 12,500 gallons per hour, 300,000 gallons per day, and 109,500,000 gallons per year. Multiply this times the 50 windmills and 5.5 billion gallons of water per year can be extracted from the atmosphere. A dedicated floating facility for just producing water could produce many times this amount making a sizable contribution to the couple of trillion gallons required by LA every year 

This water production method could easily be applied to the floating island idea espoused by the Seasteading Institute and being tested by the Maritime Research Institute Netherlands. The cool, nutrient-rich water brought up from the depths could also be used in fish farming, a burgeoning industry that lends itself as a food and revenue source to the concept of floating islands.

One thing is for certain, something must be done to assure mankind’s access to pure water. The lack of it is one of the major reasons the Middle East is in such turmoil. This political unrest can only spread as water becomes more and more scarce. I predict this method of water production will be a future godsend to the warmer climate regions of the planet.

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How It Works!

This machine extracts fresh water and electricity from the ocean using a combination of cold ocean water and wind power.  Peak Water; What We're Going To Do About It is a general description of this technology. Cold ocean water is pumped through a heat exchanger in the top of a tower. Ambient air ducted through the tower powers a turbine. Condensed water is extracted from the heat exchanger. This blog will go into more detail about unit size versus quantity of water and electricity produced.

This technology is patented. The numbers talked about here are theoretical but give a sound starting point to what can be expected of the real thing. A small prototype would 1. demonstrate that it works and 2. verify the quantities of water and electricity produced. The purpose of this article is to attract interest in this important step.

The ultimate goal is to have enough of these built and working to get back on track for CO2 emission goals and keep our climate from reaching a tipping point beyond which it will be hard to recover. Also, it is important to remember that the world is currently in a fresh water crisis. Fresh water demands were originally projected to grow by 55% between 2000 and 2050. It seems those predictions are holding true.

Here is a picture of the device for handy reference while I talk about it. Click to enlarge or zoom in.

We're going to assume the device pictured here is a 120 foot diameter cylinder about 700 feet tall with a 200 foot tall rectangular elbow on top of that. Four hundred feet is under water providing stability. It could be much smaller, but not much bigger. Also, we are going to assume the setting is the Gulf of Mexico where temperatures are warm and the air is humid (the hotter the surface environment, the better it works). The average wind speed is 18 mph, average temperature is 74.2 degrees F., and the average humidity is 60%.


We'll start at the top and work our way down. Because the wind collector is about 300 feet above the ocean's surface the wind is going to blow about 4 mph more on average. The elbow at the top gathers the wind. It is 200 feet tall and 120 feet wide. With the doors open, the wind-gathering area is about 60,000 sq. feet. This wind is squished into the top of the cylinder which has an area of 11,300 sq. feet. That is a ratio of 5.3 to 1. All that air is being scrunched up and forced down a vertical tube. With that ratio a 22  mph wind should become a category 3 hurricane of 117 mph going down this vertical tower. But it doesn't. There's a lot of frictional losses. Some of the air backs up in the collection cone and spills out around the edges. It's a process that is about 50% efficient. The air going into the top of the cylinder is only going 58 mph. It then goes through the heat exchanger. This is specially designed to allow a large throughput of air with as little friction as possible. Even so, it will reduce the air velocity by about 30%. Our 58 mph becomes 41 mph.

As the air leaves the exchanger it is much cooler (55 degrees F) and denser and begins to accelerate down in a reverse stack affect. As it drops the 200 feet to the wind turbine it gains another 15 mph to hit the turbine at 56 mph. Here's the link to input numbers to calculate the stack effect.

We will now calculate the wind power density at the turbine to find out how much energy we can extract. WPD=1/2 density of air x velocity of air cubed. In this case the wind density works out to 19,309 watts per meter squared. Our turbine area is 11,300 ft sq. That converts to 1,050 square meters. The total watts is 1,050 x 19,309 = 20,274,450 watts or 20.2 MW (megawatts).

The math involved in determining how much water will condense out on the heat exchanger is complex and dependent on a lot of variables. But we can look at how much water is available and a realistic percentage of what we can extract.

We know the open area of the heat exchanger and the velocity of air. The area is 11,300 square feet. The velocity is an average of the inlet 58 mph and the outlet 41 mph which is about 50 mph. That's about 3 billion cubic feet per hour.

There are .0094 pounds of water in a pound of air at 60% humidity. A pound of air at 74 degrees will take up about 13 cubic feet of volume. There are 230 million pounds of air going through the heat exchanger per hour. 230x.0094=2.162 so there are approximately 2.2 million pounds of water going through the exchanger per hour. That's 275,000 gallons of water per hour. Let's say we can get only 20 percent efficiency in removing this water. That's 55,000 gallons per hour times 24 equals 1,320,000 gallons of water per day. That's an average. It's nearly half a billion gallons of water per year. Free. It would provide 170,000 households their average daily consumption of 80 gallons per day. If it were bottled and sold to the public at the average price of $1.21 per gallon it would bring in close to $600,000,000 per year. But let's say only a portion was bottled and the rest pumped into the general water supply so that water brought in just $50,000,000 per year.

How much is our electricity worth? The average residential customer payed about 12.5 cents per kwh (kilowatt hour). We're producing about 200,000,000 kwh per year so that's about $22,300,000 dollars per year.

We now have combined revenues of $72,300,000 per year. How much did it cost to get there? Keep in mind this is a much simpler device than an offshore rig; even simpler than a cruise ship. A cruise ship costs about $2.50 a pound to fabricate. Let's figure we can get this built for $2.25. The unit as described above weighs about 7 million pounds. About $16 million. Transportation and anchorage $5 million. Twenty miles of cable and pipe to transport electricity and water at $1 million per mile = $20 million. Miscellaneous expenses of $2 million. That's a total of $43 million.

$72 million minus $43 million leaves $29 million in profit the first year. Second year it will be $72 million minus $2 million in maintenance. Since there are offshore rigs out there over 40 years old, we can assume our simpler structure has at least a 40 year lifespan. The total revenue is $2.8 billion. And that is just one unit. Imagine 200 units in the Gulf of Mexico, 50 on the east coast of Florida and 150 off the south coast of California. Now we're talking a trillion dollar market in the U.S. alone. Think of the Middle East, India, Pakistan, South America, South Africa, and Australia. Another couple of trillion. Per year.

Now you know what I know. A working prototype to pin down the numbers thrown about here would be a great start. If you or anyone you know might be interested in providing fresh water to our kids and their kids, let me know. Engineering skills and money is all it takes.

Thanks,

Glen Hendrix

Peak Water: What We're Going To Do About It

Photo by Jeremy Bishop on Unsplash

by Glen Hendrix

With all the talk of peak oil, it is hard to believe that something as important as peak water may have already come and gone with no equivalent hue and cry. The major constriction for producing food for a burgeoning population is water - not land. According to the International Food Policy Research Institute, nearly 5 billion people, about half of global grain production, and 45% of the GPD ($63 trillion dollars) will be at risk due to lack of water with current consumption practices. Eighteen countries; including the big-three grain producers China, India, and the U.S.; are now over-pumping their aquifers. For 20 years Saudi Arabia was self-sufficient in growing wheat. They have nearly exhausted their aquifer and will soon quit growing wheat. Recent droughts in California and Texas seem bad but there is evidence that a major portion of the Southwest U.S. underwent a 10-year drought with hardly a drop of rain several hundred years ago. An inexpensive alternative water source is needed.

Paper or plastic? There are a lot of unexpected turns and twists to the correct answer. 

One of the largest storehouses of energy lies quietly at the bottom of the ocean. It is not oil, and it is not methane hydrate. It is cold water. Specifically, it is deep ocean water, also known as DOW, from the upper levels of the Midnight Zone at 3,300 to 13,200 feet deep. Approximately 90% of the ocean by volume is deep ocean water. This water is at a temperature of 32˚ to 37˚F. More correctly, it might be called a storehouse of a relative lack of energy because it is only the combination with a more energetic (warmer) mass that results in an extractable form of energy. That more energetic mass would, of course, be the warm upper regions of the Twilight Zone and the Sunlight Zone of the ocean and the tropospheric layer of the atmosphere.

courtesy Wikipedia

Although this is the coldest water, anything 2,500 feet and deeper in the ocean is about 46˚F, which is considered "cold ocean water" and is usable for the applications described here. More than 90% of the oceans are greater than 2,500 feet. 

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The best place to exploit this temperature differential is the Tropics where the temperatures near and above the surface of the water are mild to hot year around. Fortunately, approximately 40% of the world's surface lies in the Tropics and it includes a lot of DOW and cold ocean water. While a tropical climate is the most efficient location for extracting water and power, an appreciable percentage of the North and South temperate zones have sufficiently warm weather to make this practical. For the United States that would include the coastline and offshore of states along the Gulf of Mexico, the eastern coast of Florida and the southern coast of California.

Cold ocean water in combination with warm, humid tropical and subtropical air will provide an opportunity to meet water and power needs for the future.

For just the cost of equipment and maintenance, the system described here will provide both water and electricity. It is basically a tower mounted on a spar-type, offshore platform. Deep, cold ocean water is pumped into a gas-to-liquid heat exchanger in the top of the tower. Wind is concentrated and re-directed into the heat exchanger. The air becomes cooler and the humidity condenses out onto the surface of the heat exchanger and is collected. Because cool air is denser it accelerates toward the bottom of the tower; essentially a reverse stack effect. A wind turbine at the bottom of the tower harvests the wind energy before it leaves through openings around the base of the tower. The collected water and generated electricity is sent to shore.

Another version is built on the shoreline and uses an onshore reservoir to store the water. This stored water produces electricity that makes up for slumps in production from the wind turbine.

Another version is free-floating with its own propulsion. With the ability to produce electricity and water, it will become a base for mining, aquafarming, recycling ocean plastic, or scientific studies. These could be very independent, almost like tiny nations with their own GPD and tax laws. They could move wherever needed to provide power and fresh water as well as food.

This free ranging version could work in conjunction with special sea-going barges. These would store fresh water and hydrogen from the electrolysis of sea water. When the barge is full, it is towed the nearest port in need of water and fuel.

Barge to lighter water and hydrogen to shore. Top tank is for hydrogen, bottom two for water.

The central spar provides stability for the tower even in high winds and heavy seas. Although it resembles an offshore drilling or production rig, it is much more simple and less expensive. It is even simpler than a cruise ship to construct. Cruise ships are currently running between $2 and $3 dollars per pound to construct. 

The answer to the plastic bag problem is reuse. This new device makes it easy. 

A unit 120 feet in diameter, 300 feet tall (the spar below the surface counterbalances and structurally stabilizes the tower even in high wind) could produce an estimated 20MW on average and between two and five million gallons of water per day. If it cost twice what the average cruise ship costs per pound It would tun about 50 million dollars. The electricity and water produced would retail for about 25 million dollars per year so the unit could conceivably pay for itself in two years. A hundred of these in the Gulf of Mexico could provide the same amount of water as the Brazos River watershed and as much electricity as a large nuclear plant. It would also provide the ability to cool the surface water temperature of a large area and reduce the strength of storms and hurricanes before they reach land.

Advantages:

Bird deaths eliminated.

The sound of the turbine is mitigated by the tower wall.

Flickering shadows on the surrounding landscape are eliminated.

The heat-generating rotating parts of the turbine and generator are kept cool no matter how hot the weather.

The horizontal plane allows more efficient, longer lasting bearings to be used and creates less wear on those bearings.

The horizontal plane also eliminates gravity and wind load fluctuations, making blade construction lighter and cheaper.

Seawater contacting the inner, hard-to-clean surfaces of the device is too cold and salty to form algae, minimizing maintenance.

No chemicals to leak into the environment.

Produces power even when the air is still due to the reverse stack effect.

No azimuth yaw mechanisms needed to keep turbine aligned.

Being at sea eliminates land purchase or rental or eminent domain takeovers.

Nutrient rich deep ocean water can be used for aquatic farming near the surface.

There is plenty of "fuel" since 90% of ocean water is between 32 and 37 degrees Fahrenheit and 40% of the world is tropical or subtropical.

Courtesy JiaJenn31 of Deviant Art

At the very least, this solution can bridge the gap for humanity's needs for clean power and fresh water until nuclear fusion or some other technological breakthrough can carry the load.

If you would like to know more about this technology or get involved in its development, go to Airquifer.com.