How to grow food and get fresh water in deserts near the sea
There are many places near seashores where there is very little rain. A lot of the shore region in the Middle East is classified as desert for this reason. These places are also found on the west coast of South America and southwestern part of North America. Let’s start with the fact that there is plenty of sunshine and salt water available. The water usually does not have much mineral nutrients in it but these can be easily and inexpensively added. Now consider constructing a string of connected shallow water channels with a black water proof lining. This should be done on level ground well above any possible flood level. But it should not be too high to easily pump sea water to it. If the local sea water is pumped into these channels and a small amount of fertilized is added, we will get a bloom of plankton. Now consider a continuous slow pumping of water into one end of these channels and emptying the other end into a large pool. Let’s say that the rate of pumping water into the channels is set so that The water spends several days in the channels before it enters the pool at the end. This water will have a high concentration of plankton. This is food that can be utilized in several ways. For example, the pool can be stocked with filter feeding fish. These can be harvested and eaten by humans. There are many other animals that live by filtering food from water. Probably the one that actually consumes the most plankton is krill. They, too, can be easily harvested from the water in the pool. It is also possible to use the plankton directly to prepare food for humans. Consider that the plankton is a mixture of plant and animal matter that is actually the base of the whole oceanic food chain. There is no reason that it cannot be added to other foods to increase their nutritional value. After removing the food in the pool, there will still be high levels of nutriments in it so that most of that water can be recycled back to the beginning of the water channels. There it will mix with the incoming sea water and support further growth of plankton.
But you remember that the title of this article also mentioned getting fresh water. Let’s go back to considering the water channels that are growing the plankton. Let’s say that they are about one meter wide and half a meter deep. With these dimensions, they can use common window glass that is often used for residences. They can be covered by clear glass, and the sunlight, assisted by the black lining on the bottom of the water channels will raise the temperature of the water because of the greenhouse effect. The warmer water will increase the rate of growth of the plankton and it will also increase the humidity of the air above the water. Some fresh water will then condense onto the bottom surface of the glass. If the glass panels are tilted so that the water will run down and drip off the bottom edges of the panels into small channels, that water can be collected and can be used for drinking water or irrigation. During the day, the water in the channels will get quite warm. Since water has a very high specific heat, it will store a lot of thermal energy. In desert areas, the air temperature drops quickly at night because there is little water vapor in the air to block heat radiation to space. It is common to have very large differences between day and night temperatures. At night, the glass panels will get cold and the rate of condensation will increase greatly. The evaporation of the warm water in the channels will cool the water. Therefore, the excess heat that was collected during the day will be used to distill fresh water from the salt water in the channels at night. One result of this distillation is that the concentration of salt in the water will increase and this highly salty water must be removed. After the water gets to the pool at the end of the channels, The food is utilized as described in the first paragraph. But then the salt level will be too high to recycle more than a small amount back into the channels along with the incoming salt water. Instead of discharging it back into the ocean, since it still contains useful nutrients, it can be used to create a bog on land where it will support further plant and animal life. Another use for this water would be to use it as a nutrient source for oyster beds in shallow coastal water. There would be more fresh water generated than the local residents would need. This could be used to grow large amounts of food in greenhouses for local consumption and external sale.
The energy necessary to run this system is very low, A good source would be solar electric panels used to run the sea water pumps that refill the channels. Another way of pumping the water is to use windmills. These do not need to generate electricity but can instead directly drive pumps that fill the channels with salt water. I have seen pumps constructed from old tires and scrap metal that were driven by windmills. This system is low tech and can be built and maintained by people without specialized training. Operating this system would provide livelihood for a community of people. They would provide their own food and could sell surplus food and fresh water to earn money. As the local population grows, the size of the plankton growing system can also grow. None of the materials used are consumed, except for a small amount of fertilizer, and all of the materials are inexpensive. There is labor needed to maintain the system, keep it clean and repair it when necessary. The land used will be cheap because it is otherwise unusable, so building a stable self sufficient community should be easily possible with very low start-up cost. There are thousands of suitable locations, because there are many deserts with ocean access. Just on the southern shores of the Mediterranean Sea, there could be nearly continuous strings of communities operating this way. Once these communities are functioning, there will be opportunities to develop other kinds of work for the people not directly working to maintain or build onto the basic system. This could lead to light manufacturing enterprises or many other activities.
Labels
Use of desert land, Growing food with sea water, desalinating sea water, growing and using plankton on desert land, solar distillation of sea water, small self sufficient communities. low tech industry
Saturday, December 22, 2012
Thursday, July 19, 2012
How to deal with droughts, floods, and storms
There are many areas where the rainfall is very seasonal. For example, the large regions where there are seasonal monsoon rains. During the rainy season, there is lots of water available; in fact, there is often way too much water, so that there are disastrous floods with loss of life and property. But during the dry season there is not enough water to raise crops or support marine life.
In areas where there are rivers in deep valleys, it is possible to build dams to store the extra water. But this cannot be done in flat areas. But there are things that can be done even in flat areas, to reduce the problems caused by this seasonal or intermittent rainfall. In regions that are mostly flat, such as Bangladesh, (which is mostly on a river delta that is now barely above sea level), it seems that a good plan would be to provide seasonal storage of large amounts of water. This would not be easy, but there would be many benefits. One way to do this would be to start in the beginning of the dry season, excavate a large area as deeply as possible, use most of the removed material to surround the excavation with a high levee and protect the levee with impermeable material such as common tarp fabric. This will create an artificial lake basin. The size of the lake that can be created in this way depends on the availability of a large amount of earth moving equipment so that the entire lake basin can be created in one dry season. After the levee is created, continue to excavate more material to raise the level of the surrounding area. Excavate as much material as possible before the rains begin.
When the rains come, and the rivers swell, use massive pumps to fill the lake with water from the rivers. This avoids the usual flooding for two reasons: one is that the area around the lake is now higher because of the added material that was deposited there after it was removed to make the lake, and the other reason is that the excess river water that would have contributed to the flooding has now been pumped into the lake which should be filled to the top of the levees. The lake will now have a level well above the surrounding land. During the following dry season, the lake water can be used for irrigation and other needs. The lake can also be stocked with fish, such as tilapia, so that it will produce food as well.
The following dry season, the same equipment can be used to create another lake. As more lakes are created, larger areas are protected from flooding. The elevated land will also provide protection during the periodic cyclones (hurricanes) that usually flood the land with seawater and often cause major loss of life due to drowning. The sea water deposits salt in the soil and makes it less productive until the salt is washed out, which usually does not happen until the following rainy season. The fresh water in the lake can be used to wash the salt out of the soil. Even if the raised land is not high enough to avoid flooding in the storm, the area covered by the levees will be much higher and can be topped with concrete storm shelters that will protect the local population. The levees will also have sufficient area to keep livestock out of the flooded area. The loss of livestock is now a major economic cost of the cyclones.
It will be necessary to periodically add silt to the land. This happened naturally during the seasonal floods and it kept the land fertile and maintained the level of the delta. But now that the land is no longer getting flooded every year, this silt must be added artificially. Fortunately, this will not be difficult to do. When the waters of the swollen rivers are pumped into the lakes, the silt that the water carried was also pumped into the lakes. This silt will settle out onto the bottom of the lakes and if it was not removed, eventually it would fill the lake basin. This is what happens to lakes behind dams all over the world. Eventually, these lakes fill with sediment, and the dams can no longer store water. To prevent this from happening, the silt must be removed. Fortunately, the silt is needed on the land around the lake and it can be easily be moved to the land where it is needed. This should be done during the dry season. The way to do this is to pump water from the bottom of the lake that has been mixed with a large amount of the sediment that was carried by the water that filled the lake. This sediment must be mechanically stirred into the water. This pumped water will be mixed with as much sediment as it can carry and it should be used to flood a small area in the vicinity of the lake. As a result, this area will be raised and fertilized. The following year, this area will support high agricultural productivity. Each year the same thing should be done to a different area. The result will be that the delta will be gradually raised, it will be periodically fertilized and the lake will not fill with silt. In fact this process can even be used to make the lake deeper so that it can store more water this procedure will result in a stable long term productive and safe area which can support many people
Obviously, this is not a cheap project. It requires massive earth moving equipment and pumps, and the energy necessary to run them. However, it will be seen to be a good investment when compared to the cost of the flood damage and the life and health consequences of not doing it. It will also increase the dry season agricultural production that the irrigation water makes possible. There may eventually be some difficulty getting fuel for the earth moving equipment as CO2 limits become more common and fossil fuel become less available, but during the dry season when the equipment is used, there should be ample sunlight to produce power. Earth moving equipment should be easily modified for battery operation because this type of equipment does not have to move far or fast and weight is usually not an issue. There are already totally electric busses used in California that can be recharged in a few minutes after completing their runs. The power needs of earth moving equipment should be similar to the needs of the busses. The addition of the solar panels necessary to provide electric power for the earth moving equipment will also provide shaded areas that can be used by farm animals as protection from the hot daytime sun. When the earth moving equipment is not actively using the power, it can be used by the community. When the lake is finished, the earth moving equipment can be moved to another area to create more lakes.
As rainfall patterns change during the global warming transition, there are frequent floods and also droughts in areas that have been accustomed to more predictable weather. Australia, Texas, and other places in the US Midwest have had droughts that were followed by wildfires that burned the dry vegetation and could not be stopped. The same areas were also subject to record breaking rainfalls that caused severe flood damage. This type of weather pattern is expected to recur. Therefore, the creation of artificial lakes, as described above would be a cost effective way to deal with both the water shortages and the flooding. Both earth moving equipment and pumps would be needed, but just as in the monsoon areas, the cost would be far less than the damage caused by the severe weather.
In another article in this blog, (Heat pipes and uses Revised) there is a description of a method for getting free air conditioning that also utilizes a large pool of water. This water can also be used for fire protection. It can even be used to provide water for an automatic system that enables homes to protect themselves from wildfires.
In the eastern USA there are sometimes very heavy rains caused by hurricanes that cause flooding over large areas. The floods are caused not only by the rain, but also by the storm surges that are caused by the hurricane winds. One area that has been affected in this way is southern Florida and the gulf coast. But builders in that region have developed an effective solution that permits residential development, flood control, and high land values. That solution is to raise the level of the land by creating networks of canals. The canals are created by excavation and the removed material is used to raise the level of the land near the canal. This makes the land more valuable for home building because it no longer floods and also because all of the houses are now waterfront properties, and residents can have boat docks in their back yards. In this way, areas that were low value swamplands have been converted to high value residential properties. The canals drain into the ocean, but the drains are controlled by movable gates. This makes it possible to control the water level in the canals and also to block storm surges from the ocean so that the canals do not overflow during hurricanes.
In areas of river deltas, this technique could still be used, but the different character of the land must be considered. In Florida, the land is composed of ancient coral and seafloor deposits. This means that it does not subside easily and the raised land around the canals will be stable. However, the material of river deltas is composed of soft silt that was deposited by the river and which tends to sink as the water in it is reduced by compression. The silt is also easily washed back into the canals by rains unless the surface is stabilized by dense vegetation. This means that, while it is possible to create canals, they are difficult to maintain and may need to be periodically dredged and have the material re-deposited on the adjacent land.
Bill Isecke
There are many areas where the rainfall is very seasonal. For example, the large regions where there are seasonal monsoon rains. During the rainy season, there is lots of water available; in fact, there is often way too much water, so that there are disastrous floods with loss of life and property. But during the dry season there is not enough water to raise crops or support marine life.
In areas where there are rivers in deep valleys, it is possible to build dams to store the extra water. But this cannot be done in flat areas. But there are things that can be done even in flat areas, to reduce the problems caused by this seasonal or intermittent rainfall. In regions that are mostly flat, such as Bangladesh, (which is mostly on a river delta that is now barely above sea level), it seems that a good plan would be to provide seasonal storage of large amounts of water. This would not be easy, but there would be many benefits. One way to do this would be to start in the beginning of the dry season, excavate a large area as deeply as possible, use most of the removed material to surround the excavation with a high levee and protect the levee with impermeable material such as common tarp fabric. This will create an artificial lake basin. The size of the lake that can be created in this way depends on the availability of a large amount of earth moving equipment so that the entire lake basin can be created in one dry season. After the levee is created, continue to excavate more material to raise the level of the surrounding area. Excavate as much material as possible before the rains begin.
When the rains come, and the rivers swell, use massive pumps to fill the lake with water from the rivers. This avoids the usual flooding for two reasons: one is that the area around the lake is now higher because of the added material that was deposited there after it was removed to make the lake, and the other reason is that the excess river water that would have contributed to the flooding has now been pumped into the lake which should be filled to the top of the levees. The lake will now have a level well above the surrounding land. During the following dry season, the lake water can be used for irrigation and other needs. The lake can also be stocked with fish, such as tilapia, so that it will produce food as well.
The following dry season, the same equipment can be used to create another lake. As more lakes are created, larger areas are protected from flooding. The elevated land will also provide protection during the periodic cyclones (hurricanes) that usually flood the land with seawater and often cause major loss of life due to drowning. The sea water deposits salt in the soil and makes it less productive until the salt is washed out, which usually does not happen until the following rainy season. The fresh water in the lake can be used to wash the salt out of the soil. Even if the raised land is not high enough to avoid flooding in the storm, the area covered by the levees will be much higher and can be topped with concrete storm shelters that will protect the local population. The levees will also have sufficient area to keep livestock out of the flooded area. The loss of livestock is now a major economic cost of the cyclones.
It will be necessary to periodically add silt to the land. This happened naturally during the seasonal floods and it kept the land fertile and maintained the level of the delta. But now that the land is no longer getting flooded every year, this silt must be added artificially. Fortunately, this will not be difficult to do. When the waters of the swollen rivers are pumped into the lakes, the silt that the water carried was also pumped into the lakes. This silt will settle out onto the bottom of the lakes and if it was not removed, eventually it would fill the lake basin. This is what happens to lakes behind dams all over the world. Eventually, these lakes fill with sediment, and the dams can no longer store water. To prevent this from happening, the silt must be removed. Fortunately, the silt is needed on the land around the lake and it can be easily be moved to the land where it is needed. This should be done during the dry season. The way to do this is to pump water from the bottom of the lake that has been mixed with a large amount of the sediment that was carried by the water that filled the lake. This sediment must be mechanically stirred into the water. This pumped water will be mixed with as much sediment as it can carry and it should be used to flood a small area in the vicinity of the lake. As a result, this area will be raised and fertilized. The following year, this area will support high agricultural productivity. Each year the same thing should be done to a different area. The result will be that the delta will be gradually raised, it will be periodically fertilized and the lake will not fill with silt. In fact this process can even be used to make the lake deeper so that it can store more water this procedure will result in a stable long term productive and safe area which can support many people
Obviously, this is not a cheap project. It requires massive earth moving equipment and pumps, and the energy necessary to run them. However, it will be seen to be a good investment when compared to the cost of the flood damage and the life and health consequences of not doing it. It will also increase the dry season agricultural production that the irrigation water makes possible. There may eventually be some difficulty getting fuel for the earth moving equipment as CO2 limits become more common and fossil fuel become less available, but during the dry season when the equipment is used, there should be ample sunlight to produce power. Earth moving equipment should be easily modified for battery operation because this type of equipment does not have to move far or fast and weight is usually not an issue. There are already totally electric busses used in California that can be recharged in a few minutes after completing their runs. The power needs of earth moving equipment should be similar to the needs of the busses. The addition of the solar panels necessary to provide electric power for the earth moving equipment will also provide shaded areas that can be used by farm animals as protection from the hot daytime sun. When the earth moving equipment is not actively using the power, it can be used by the community. When the lake is finished, the earth moving equipment can be moved to another area to create more lakes.
As rainfall patterns change during the global warming transition, there are frequent floods and also droughts in areas that have been accustomed to more predictable weather. Australia, Texas, and other places in the US Midwest have had droughts that were followed by wildfires that burned the dry vegetation and could not be stopped. The same areas were also subject to record breaking rainfalls that caused severe flood damage. This type of weather pattern is expected to recur. Therefore, the creation of artificial lakes, as described above would be a cost effective way to deal with both the water shortages and the flooding. Both earth moving equipment and pumps would be needed, but just as in the monsoon areas, the cost would be far less than the damage caused by the severe weather.
In another article in this blog, (Heat pipes and uses Revised) there is a description of a method for getting free air conditioning that also utilizes a large pool of water. This water can also be used for fire protection. It can even be used to provide water for an automatic system that enables homes to protect themselves from wildfires.
In the eastern USA there are sometimes very heavy rains caused by hurricanes that cause flooding over large areas. The floods are caused not only by the rain, but also by the storm surges that are caused by the hurricane winds. One area that has been affected in this way is southern Florida and the gulf coast. But builders in that region have developed an effective solution that permits residential development, flood control, and high land values. That solution is to raise the level of the land by creating networks of canals. The canals are created by excavation and the removed material is used to raise the level of the land near the canal. This makes the land more valuable for home building because it no longer floods and also because all of the houses are now waterfront properties, and residents can have boat docks in their back yards. In this way, areas that were low value swamplands have been converted to high value residential properties. The canals drain into the ocean, but the drains are controlled by movable gates. This makes it possible to control the water level in the canals and also to block storm surges from the ocean so that the canals do not overflow during hurricanes.
In areas of river deltas, this technique could still be used, but the different character of the land must be considered. In Florida, the land is composed of ancient coral and seafloor deposits. This means that it does not subside easily and the raised land around the canals will be stable. However, the material of river deltas is composed of soft silt that was deposited by the river and which tends to sink as the water in it is reduced by compression. The silt is also easily washed back into the canals by rains unless the surface is stabilized by dense vegetation. This means that, while it is possible to create canals, they are difficult to maintain and may need to be periodically dredged and have the material re-deposited on the adjacent land.
Bill Isecke
Thursday, July 14, 2011
Wave powered propulsion for ships
Wave Powered Propulsion for Ships
Fish, marine mammals, and humans wearing flippers all propel themselves through the water the same way. That way is to use a semi flexible fin or tail that is driven sideways relative to the direction of motion of the user. The motion of the fin causes it to bend and the force exerted on the water by the leading side of the fin pushes the water backwards as well as sideways. When the fin is driven in the opposite direction, it bends the other way and once again there is a backward as well as a sideways force pushing the water. As the fin is driven from side to side, the sideways forces balance each other out, but the backwards forces add and the result of driving the water backwards is that the fish or whatever is driving the fin from side to side is propelled forwards.
Now, it’s a funny thing; it doesn’t matter if the fish is pushing the fin or if the water is pushing the fin. Think about it: if a dead fish somehow had the water behind its fin moving left and right (I will leave it to your imagination exactly how this might come about), the result would be the same. The fin would still bend, and the elasticity of the fin will cause it to try and straighten, which means that the elastic force is pushing back against the water. Again, the side to side forces balance out, but the backward forces add. You see?
So let’s consider the case of a fin that is mounted on the back of a boat but is well under the surface of the water. We will picture a horizontal fin that is strongly connected to the structure of the boat. If the boat is in water that has waves, the waves will exert a force on the fin that causes it to bend. Sometimes the fin will be bent down and sometimes up. As the waves bend the fin, the force bending it is also partly directed towards the front of the boat. If the fin is semi flexible (or springy), it will try to bend back again and so will produce a force on the water that is partly pushing the water away from the boat towards the back. Again, this produces a force towards the front of the boat. Of course, it also pushes up or down, but, again, those backwards forces are the only ones that aren’t balanced out. So the result is that the boat is pushed forward as the water is pushed back.
Now imagine that similar fins are placed on both sides of the boat. They are all horizontal and all connected to the boat, but the ones on the sides are actually connected to vertical poles that are sticking straight down into the water but a few feet away from the sides of the boat. The poles are connected to the boat so that they move along with the boat while remaining straight up and down. The fins are connected to the poles and are facing the back of the boat. These fins are also well beneath the surface of the water and the front of each fin is connected to the pole so that it is horizontal and the front part of the fin is connected so that it stays horizontal even when a wave bends the back part of the fin up or down. Each of these fins now act just like the one connected to the back of the boat that we described in the last paragraph. Each of them produces a force directed towards the front of the boat. A boat can have several of these poles on each side, and each pole can have several fins mounted on it.
The following is a description of a possible commercial use of this basic principal.
Ships travelling through waters with significant wave activity experience a strong Up/Down component of water motion relative to the sides of the ship due directly to the waves and also to the motion of the ship as it rocks and pitches. This motion may be used to provide thrust to propel the ship either alone or by assisting the ship’s engine. There is considerable potential energy in waves and some of this energy can be used to propel ships.
The propelling force is generated by connecting flat plates horizontally below the water level so that the connected edge of the plates face the front of the ship and are connected to a vertical shaft that is parallel to the side of the ship but removed from it so that the plate can move up and down. The plates are connected to the shafts by strong springs that hold the plates horizontal but permit them to move up or down when strong wave action pushes them. When the rear parts of the plates are pushed up or down, the springs will exert a force on the plates attempting to restore them to a horizontal position. A part of that force will be directed towards the front of the ship. The fraction of the total force on the plate that is directed toward the front of the ship is given by the sine of the angle that the plate makes with the horizontal. There will always be a forward force even for a small deflection of the plate, for example if the engine is also being used, the plate could still increase the speed of the ship.
One way of configuring this system would be to have strong horizontal poles extending from the side of the ship. At the outboard end of each pole there would be another pole that extends down vertically several feet into the water and is rigidly fixed to the first pole. On this pole are mounted several plates with springs. The poles that extend horizontally from the side of the ship are held by bearings that make them free to rotate, but limit their motion, so that the vertical poles at the end can tip towards the back of the ship but not forward. This permits the system to be pulled up out of the water when it is not needed and also protects it from damage if it is hit by large floating debris. In this case the vertical poles would simply move back and rotate up out of the way. Obviously, there would be many such poles on both sides of the ship.
This system would not drive a ship as fast as would a powerful engine, but it does not use any fuel. As Fossil fuels become more scarce and costly, the wave propulsion system becomes more economical, particularly for cargos that do not have a large time value such as bulk commodities. If all bulk commodity shipments were transported in this way, the total number of ships used would have to increase because of the greater transit time. However, there is currently a large surplus of unused ships which could be retrofitted with this system and put back into service.
By Bill Isecke,
July 14 2011
Fish, marine mammals, and humans wearing flippers all propel themselves through the water the same way. That way is to use a semi flexible fin or tail that is driven sideways relative to the direction of motion of the user. The motion of the fin causes it to bend and the force exerted on the water by the leading side of the fin pushes the water backwards as well as sideways. When the fin is driven in the opposite direction, it bends the other way and once again there is a backward as well as a sideways force pushing the water. As the fin is driven from side to side, the sideways forces balance each other out, but the backwards forces add and the result of driving the water backwards is that the fish or whatever is driving the fin from side to side is propelled forwards.
Now, it’s a funny thing; it doesn’t matter if the fish is pushing the fin or if the water is pushing the fin. Think about it: if a dead fish somehow had the water behind its fin moving left and right (I will leave it to your imagination exactly how this might come about), the result would be the same. The fin would still bend, and the elasticity of the fin will cause it to try and straighten, which means that the elastic force is pushing back against the water. Again, the side to side forces balance out, but the backward forces add. You see?
So let’s consider the case of a fin that is mounted on the back of a boat but is well under the surface of the water. We will picture a horizontal fin that is strongly connected to the structure of the boat. If the boat is in water that has waves, the waves will exert a force on the fin that causes it to bend. Sometimes the fin will be bent down and sometimes up. As the waves bend the fin, the force bending it is also partly directed towards the front of the boat. If the fin is semi flexible (or springy), it will try to bend back again and so will produce a force on the water that is partly pushing the water away from the boat towards the back. Again, this produces a force towards the front of the boat. Of course, it also pushes up or down, but, again, those backwards forces are the only ones that aren’t balanced out. So the result is that the boat is pushed forward as the water is pushed back.
Now imagine that similar fins are placed on both sides of the boat. They are all horizontal and all connected to the boat, but the ones on the sides are actually connected to vertical poles that are sticking straight down into the water but a few feet away from the sides of the boat. The poles are connected to the boat so that they move along with the boat while remaining straight up and down. The fins are connected to the poles and are facing the back of the boat. These fins are also well beneath the surface of the water and the front of each fin is connected to the pole so that it is horizontal and the front part of the fin is connected so that it stays horizontal even when a wave bends the back part of the fin up or down. Each of these fins now act just like the one connected to the back of the boat that we described in the last paragraph. Each of them produces a force directed towards the front of the boat. A boat can have several of these poles on each side, and each pole can have several fins mounted on it.
The following is a description of a possible commercial use of this basic principal.
Ships travelling through waters with significant wave activity experience a strong Up/Down component of water motion relative to the sides of the ship due directly to the waves and also to the motion of the ship as it rocks and pitches. This motion may be used to provide thrust to propel the ship either alone or by assisting the ship’s engine. There is considerable potential energy in waves and some of this energy can be used to propel ships.
The propelling force is generated by connecting flat plates horizontally below the water level so that the connected edge of the plates face the front of the ship and are connected to a vertical shaft that is parallel to the side of the ship but removed from it so that the plate can move up and down. The plates are connected to the shafts by strong springs that hold the plates horizontal but permit them to move up or down when strong wave action pushes them. When the rear parts of the plates are pushed up or down, the springs will exert a force on the plates attempting to restore them to a horizontal position. A part of that force will be directed towards the front of the ship. The fraction of the total force on the plate that is directed toward the front of the ship is given by the sine of the angle that the plate makes with the horizontal. There will always be a forward force even for a small deflection of the plate, for example if the engine is also being used, the plate could still increase the speed of the ship.
One way of configuring this system would be to have strong horizontal poles extending from the side of the ship. At the outboard end of each pole there would be another pole that extends down vertically several feet into the water and is rigidly fixed to the first pole. On this pole are mounted several plates with springs. The poles that extend horizontally from the side of the ship are held by bearings that make them free to rotate, but limit their motion, so that the vertical poles at the end can tip towards the back of the ship but not forward. This permits the system to be pulled up out of the water when it is not needed and also protects it from damage if it is hit by large floating debris. In this case the vertical poles would simply move back and rotate up out of the way. Obviously, there would be many such poles on both sides of the ship.
This system would not drive a ship as fast as would a powerful engine, but it does not use any fuel. As Fossil fuels become more scarce and costly, the wave propulsion system becomes more economical, particularly for cargos that do not have a large time value such as bulk commodities. If all bulk commodity shipments were transported in this way, the total number of ships used would have to increase because of the greater transit time. However, there is currently a large surplus of unused ships which could be retrofitted with this system and put back into service.
By Bill Isecke,
July 14 2011
Tuesday, October 26, 2010
Heat pipes and uses Revised
The heat pipe and some important uses for it
The heat pipe is a simple device. Although it is not new, I believe that there are some important applications for it that have not been exploited. These applications could provide a low-cost way of improving life for people in many places in the world.
You are probably familiar with the fact that when you have wet hands and they dry in the wind, they feel cold. That is an example of heat being absorbed due to liquid becoming a gas, or evaporating. When gas condenses back to liquid, that heat is released. This principle is used to transfer heat in a heat pipe. One end of the pipe absorbs heat because liquid is becoming a gas, and the other end releases heat (or becomes warm) because the gas is changing back to a liquid. In a heat pipe, the same liquid is constantly being vaporized (and absorbing heat) and then condensing at the other end of the pipe and releasing the heat. The liquid then returns to the other end where it evaporates again. You can think of it as similar to a bar of copper that is a good conductor of heat, but a heat pipe is a much better conductor of heat than any metal and can conduct a lot of heat over long distances while keeping the hot and cold ends of the pipe at nearly the same temperature. You might think of it as a kind of superconductor for heat.
The following type of heat pipe will transfer heat in only one direction. It is a sealed pipe that has one end higher than the other. It contains a liquid in its bottom and the gaseous vapor of that liquid in the top. Air has been eliminated, leaving only the liquid and its vapor. There are several liquids that can be used for this purpose including Freon and ammonia, but one practical and low cost choice is propane. Whenever the temperature of the liquid in the bottom of the pipe is higher than the temperature at the top of the pipe, the liquid boils, turning it to gas. As the liquid turns to gas, heat is absorbed. The gas will condense back into liquid at the top because it is cooler there, and the liquid will then run back to the bottom of the pipe. This process can efficiently transfer a lot of heat from the bottom of the pipe to the top, and it can do it with very little temperature difference between the bottom and top. Since the applications discussed here all use the pipe to transfer heat from the bottom of the pipe to the top, the fact that it will not transfer heat from the top to the bottom is important and welcome.
(See construction hints and further explanations of the heat pipe at the end of the article below)
Here are some suggested uses:
residential temperature control for hot dry areas.
In areas such as southern California, the Middle East, and in deserts, the days are hot but the nights are much cooler, particularly when the sky is clear and heat can easily radiate into space. In places such as these, any pool of water can be cooled at night and used as a source of cold water for air conditioning during the day. The process of cooling the water during the night uses no power at all because it uses a heat pipe.
This is how it works: The heat pipe will cool the pool of water whenever the water is warmer than the top of the pipe. This will happen during the night, when the outside temperature drops well below the daytime temperature.
To increase the efficiency of cooling the pool, the bottom of the pipe, where heat is absorbed, can be divided into branches that are spread near the surface of the water pool. Heat should be removed from the top of the water since cool water is denser than warm, therefore the warmest water will always be at the top. If the heat were removed from the bottom, the water at the top would remain warm and only the bottom water would be cooled. The result would be a pool with temperature stratification and reduced ability to store heat.
The top of the pipe can also be divided into branches that are thermally connected to a large radiating surface on the roof of the house or, if not on the roof, at least somewhat higher than the pool. (This is because this type of heat pipe only works if the end that is cooled is higher than the end that provides the heat.) For example, if the pool is underground, the radiating surface can be at ground level. Placing the radiator over the pool insulation can save space. The radiator should consist of metal panels coated with a material that efficiently radiates heat during the night. Copper panels that have been soldered to the heat pipe and then painted black will work effectively. If possible, the radiator panels should face the open sky to maximize the amount of heat that is radiated. The cold night air will also help cool the radiator.
The heat that is dissipated during the night will lower the temperature of the water pool so that the cold water can be used to cool the inside of the house during the day. Since the inside of the house is insulated to reduce the amount of heat that can enter from the outside environment, a modest amount of cold water can keep the house comfortably cool all day. This system only needs to use a small amount of power to circulate the cold water through radiators inside the house during the day. This power will be far, far lower than the power necessary to run an air conditioner. Note that if the water pool is above the living area in the house, then no power at all need be used as a thermosiphon can be used to circulate the cold water below the pool above the living space. An alternate system would simply use the bottom of the pool as the ceiling of the living space. Either of these systems would use no power, but would need manual control to avoid having the living area too cold. The thermosiphon would simply need a valve to shut off the water flow. The cold ceiling would need movable insulation to stop the cooling process when necessary .
Use of water for fire protection ETC
Recently, uncontrolled forest fires in California and in Australia caused the destruction of many houses and also loss of lives, because the size and speed of the fires made it impossible for the local fire protection services to protect the houses and residents.
Houses that used the cooling system described above would have a large amount of water available if needed for firefighting or dealing with temporary water shortages due to drought. When wildfires approach, residents are required to leave the area for their own safety. In addition, electrical power is usually not available. However, a house can protect itself from forest fires by use of a battery powered automatic system that senses the heat of an approaching fire and responds by spraying a large amount of water on the house and from the roof of the house to soak the house and the area around the house for about 100 feet. This system could save the house even if an uncontrolled fire destroyed the surrounding region. I do not know of any houses that had this kind of system installed, but people may wish to do so now to avoid future losses.. Fire insurance companies may encourage use of this system by offering reduced rates for houses that are protected in this way. They can also make sure that the system is properly sized and installed by requiring that the installation meet standards for functionality before qualifying for the reduced rate.
Investing in this system combined with the free or low cost air conditioning described above would definitely be a long term investment that would pay for itself by saving energy costs, and quite possibly, by saving the house itself
Creating large amounts of ice in temperate areas
In temperate areas, lakes and other bodies of water will freeze on the surface during the winter. However, the surface ice is a poor conductor of heat, so the deep water below does not freeze. If it is desired to freeze the deep water, the heat pipes can be used to conduct the heat from the deep water and transfer it to the air whenever the air temperature is below the temperature of the water.
In this way, a small lake or a disused quarry can be completely frozen and can serve as a summer source of ice or icy water for a nearby community. This can be also used for low cost air conditioning during the summer. Covering the surface of the water with an insulating blanket so that the ice will not melt too quickly during the hot days of summer will help preserve the ice.
For recreational skating, the thickness of the ice on a lake or pond can be rapidly increased to make a safe ice skating area that will be available much sooner in the winter than usual, and the thicker ice will last longer in the spring.
preserving permafrost in arctic areas.
Permafrost is found in areas where the average year round temperature is below freezing. The ground water is permanently frozen and so the ground, which is actually a very deep bog was hard enough to support heavy structures.
As a likely consequence of global warming, the permafrost in large areas of Alaska and similar places is slowly melting. This is causing major problems because the frozen ground was relied on for the support of many structures As the permafrost melts, the ground often turns into a soft bog that cannot support anything heavy. Although the permafrost does not melt quickly, as the average yearly temperature increases, it does eventually melt and structures begin to sink into the soft bog
The Trans Alaska Pipeline uses heat pipes in the support posts for the pipeline to prevent melting of the permafrost under the supports. This is successful but the heat pipes used are very expensive. The pipes that are described in this article are much less costly and can be made and installed by anyone with basic mechanical skills.
The heat pipes described here can refreeze the ground during the winter when very cold temperatures are common. If there is a heat pipe that penetrates deeply into the ground and extends above the ground, the above ground portion that is cooled by the extremely cold winter air will transfer the heat from deep underground and reduce the underground temperature around the pipe rapidly to the temperature of the air. To increase the efficiency of this process, the top of the heat pipe can be fitted with fins that help remove the heat. During the summer, the underground temperature will remain low because the pipe will not transfer heat down and the soil will insulate the subsurface frozen ground from the warm air above. The volume of the subsurface frozen region will increase over several seasons as the heat pipe continues to remove heat from deep below the surface.
The heat pipes described here are low in cost because they consist of nothing but a sealed pipe that has a small amount of propane or similar liquid in it. If the pipes are made of a metal that will not corrode, the pipes will last for many years. A large number of them can be used to protect, roads, buildings, or anything else that relies on permafrost for support.
Here is a simple technique to get the heat pipes into the frozen ground. Since the heat pipes are made from copper tubing, which is too soft to be driven into the ground directly, we can use a strong steel pipe to penetrate the ground. The steel pipe must be long enough to reach the necessary depth of the heat pipe. The pipe should have a pointed insert at the bottom end, which can be driven into the ground by the pipe. When the steel pipe reaches the depth desired, the copper tube can be inserted into the top of the pipe, and then the pipe can be extracted from the ground, leaving the pointed insert and the bottom of the copper tube both at the bottom of the hole that the pipe made in the ground. As the steel pipe is pulled out, the copper tube can remain stationery. It may be useful to pour sand down the pipe as it is being extracted so that the copper tubing will have good thermal contact with the walls of the hole made by the steel pipe. When the steel pipe is completely extracted, the copper tube will remain with one end buried as far as the steel pipe was driven, and the remainder of the length of the copper tube will be above ground and ready to be fitted with fins to help cool the ground deep below the surface. It will probably be necessary to provide some mechanical support and protection for the copper heat pipe and the heat-radiating fins near the ground surface.
Construction Hints
In order to keep costs down, the pipes should be constructed on site. A practical and economical method of construction is to use copper pipe filled with liquid propane up to the highest level where you want to absorb heat. The top of the pipe can have a common tire valve fitting to permit filling and sealing. Use a vacuum pump to remove air from the pipe then admit a pre-computed weight of propane. This weight can be found by multiplying the length of pipe that you want filled with propane by the cross sectional area of the pipe. This will give you the volume of liquid propane needed. Then multiply that volume (in liters) by 540 grams to get the weight of propane needed to fill the pipe. Start by weighing the propane tank on a scale then, using a flexible hose, start filling the pipe and stop when the scale shows that the desired weight of propane has entered the pipe. Any residual air can be removed by releasing a small amount of gas from the top of the pipe. Screwing a cap onto the valve can then securely seal the pipe. Since the propane is flammable, it would be best to keep the entire pipe outdoors so that in the event of a leak the propane would be safely dispersed to the atmosphere.
Most types of plastic pipe are unsuitable because the propane will slowly diffuse through the plastic and escape.
Propane would be suitable for use because the pressure that would be generated would be well within the capability of ordinary half to one inch copper pipe that can be assembled with sweat solder fittings using the common tin/antimony solder that is used in domestic water systems. The rated working pressure of ordinary one half to one inch copper tubing is around 500 PSI and the pressure of propane at 250 degrees F is about half that, so the heat pipe system has a good pressure safety factor. Keep in mind that the pressure in the system is determined by the temperature of the water in the pool and not by the temperature of the radiating surface at the top, so the propane pressure will never get very high. For more information about copper pipes see: http://www.copper.org/publications/pub_list/pdf/copper_tube_handbook.pdf
As for transferring a large amount of heat, this should not be a problem. Think of a common residential steam heating system. This operates with water as a working fluid but is otherwise similar. Many of these systems use a single pipe to carry the steam to radiators several floors above the boiler. The same pipe carries the liquid condensed water back to the boiler. This familiar system is capable of transferring the heat necessary to heat a house in very cold weather. It also contains nothing but liquid water and water vapor. In operation, the air has been eliminated by the automatic valves found at the radiators that vent air out of the system but close to prevent steam from escaping. If the descending liquid interferes with the rising gas, there are two symptoms that would indicate the problem. The first is that the temperature difference between the top radiator, and the heat source would increase, and the second one is that there may be audible gurgling sounds from the turbulent flow of condensate. There are two simple solutions to this problem. They are both often used in steam heating systems, the first is to use a large pipe for a single pipe system and the second is to provide a separate pipe for returning the liquid condensate to the boiler. Either of these solutions could be used in the heat pipe system described above, but will probably not be necessary because this system works slowly over a long time period and never needs to quickly transfer a lot of heat.
If the system is for use inside a residence, it would be preferable to use Freon as the working fluid to avoid any danger in case of leaking propane. This would work equally well but the cost of the Freon would be higher.
Labels: Free water chilling, fire protection, how heat pipes work, low cost air conditioning, preserving permafrost
The heat pipe is a simple device. Although it is not new, I believe that there are some important applications for it that have not been exploited. These applications could provide a low-cost way of improving life for people in many places in the world.
You are probably familiar with the fact that when you have wet hands and they dry in the wind, they feel cold. That is an example of heat being absorbed due to liquid becoming a gas, or evaporating. When gas condenses back to liquid, that heat is released. This principle is used to transfer heat in a heat pipe. One end of the pipe absorbs heat because liquid is becoming a gas, and the other end releases heat (or becomes warm) because the gas is changing back to a liquid. In a heat pipe, the same liquid is constantly being vaporized (and absorbing heat) and then condensing at the other end of the pipe and releasing the heat. The liquid then returns to the other end where it evaporates again. You can think of it as similar to a bar of copper that is a good conductor of heat, but a heat pipe is a much better conductor of heat than any metal and can conduct a lot of heat over long distances while keeping the hot and cold ends of the pipe at nearly the same temperature. You might think of it as a kind of superconductor for heat.
The following type of heat pipe will transfer heat in only one direction. It is a sealed pipe that has one end higher than the other. It contains a liquid in its bottom and the gaseous vapor of that liquid in the top. Air has been eliminated, leaving only the liquid and its vapor. There are several liquids that can be used for this purpose including Freon and ammonia, but one practical and low cost choice is propane. Whenever the temperature of the liquid in the bottom of the pipe is higher than the temperature at the top of the pipe, the liquid boils, turning it to gas. As the liquid turns to gas, heat is absorbed. The gas will condense back into liquid at the top because it is cooler there, and the liquid will then run back to the bottom of the pipe. This process can efficiently transfer a lot of heat from the bottom of the pipe to the top, and it can do it with very little temperature difference between the bottom and top. Since the applications discussed here all use the pipe to transfer heat from the bottom of the pipe to the top, the fact that it will not transfer heat from the top to the bottom is important and welcome.
(See construction hints and further explanations of the heat pipe at the end of the article below)
Here are some suggested uses:
residential temperature control for hot dry areas.
In areas such as southern California, the Middle East, and in deserts, the days are hot but the nights are much cooler, particularly when the sky is clear and heat can easily radiate into space. In places such as these, any pool of water can be cooled at night and used as a source of cold water for air conditioning during the day. The process of cooling the water during the night uses no power at all because it uses a heat pipe.
This is how it works: The heat pipe will cool the pool of water whenever the water is warmer than the top of the pipe. This will happen during the night, when the outside temperature drops well below the daytime temperature.
To increase the efficiency of cooling the pool, the bottom of the pipe, where heat is absorbed, can be divided into branches that are spread near the surface of the water pool. Heat should be removed from the top of the water since cool water is denser than warm, therefore the warmest water will always be at the top. If the heat were removed from the bottom, the water at the top would remain warm and only the bottom water would be cooled. The result would be a pool with temperature stratification and reduced ability to store heat.
The top of the pipe can also be divided into branches that are thermally connected to a large radiating surface on the roof of the house or, if not on the roof, at least somewhat higher than the pool. (This is because this type of heat pipe only works if the end that is cooled is higher than the end that provides the heat.) For example, if the pool is underground, the radiating surface can be at ground level. Placing the radiator over the pool insulation can save space. The radiator should consist of metal panels coated with a material that efficiently radiates heat during the night. Copper panels that have been soldered to the heat pipe and then painted black will work effectively. If possible, the radiator panels should face the open sky to maximize the amount of heat that is radiated. The cold night air will also help cool the radiator.
The heat that is dissipated during the night will lower the temperature of the water pool so that the cold water can be used to cool the inside of the house during the day. Since the inside of the house is insulated to reduce the amount of heat that can enter from the outside environment, a modest amount of cold water can keep the house comfortably cool all day. This system only needs to use a small amount of power to circulate the cold water through radiators inside the house during the day. This power will be far, far lower than the power necessary to run an air conditioner. Note that if the water pool is above the living area in the house, then no power at all need be used as a thermosiphon can be used to circulate the cold water below the pool above the living space. An alternate system would simply use the bottom of the pool as the ceiling of the living space. Either of these systems would use no power, but would need manual control to avoid having the living area too cold. The thermosiphon would simply need a valve to shut off the water flow. The cold ceiling would need movable insulation to stop the cooling process when necessary .
Use of water for fire protection ETC
Recently, uncontrolled forest fires in California and in Australia caused the destruction of many houses and also loss of lives, because the size and speed of the fires made it impossible for the local fire protection services to protect the houses and residents.
Houses that used the cooling system described above would have a large amount of water available if needed for firefighting or dealing with temporary water shortages due to drought. When wildfires approach, residents are required to leave the area for their own safety. In addition, electrical power is usually not available. However, a house can protect itself from forest fires by use of a battery powered automatic system that senses the heat of an approaching fire and responds by spraying a large amount of water on the house and from the roof of the house to soak the house and the area around the house for about 100 feet. This system could save the house even if an uncontrolled fire destroyed the surrounding region. I do not know of any houses that had this kind of system installed, but people may wish to do so now to avoid future losses.. Fire insurance companies may encourage use of this system by offering reduced rates for houses that are protected in this way. They can also make sure that the system is properly sized and installed by requiring that the installation meet standards for functionality before qualifying for the reduced rate.
Investing in this system combined with the free or low cost air conditioning described above would definitely be a long term investment that would pay for itself by saving energy costs, and quite possibly, by saving the house itself
Creating large amounts of ice in temperate areas
In temperate areas, lakes and other bodies of water will freeze on the surface during the winter. However, the surface ice is a poor conductor of heat, so the deep water below does not freeze. If it is desired to freeze the deep water, the heat pipes can be used to conduct the heat from the deep water and transfer it to the air whenever the air temperature is below the temperature of the water.
In this way, a small lake or a disused quarry can be completely frozen and can serve as a summer source of ice or icy water for a nearby community. This can be also used for low cost air conditioning during the summer. Covering the surface of the water with an insulating blanket so that the ice will not melt too quickly during the hot days of summer will help preserve the ice.
For recreational skating, the thickness of the ice on a lake or pond can be rapidly increased to make a safe ice skating area that will be available much sooner in the winter than usual, and the thicker ice will last longer in the spring.
preserving permafrost in arctic areas.
Permafrost is found in areas where the average year round temperature is below freezing. The ground water is permanently frozen and so the ground, which is actually a very deep bog was hard enough to support heavy structures.
As a likely consequence of global warming, the permafrost in large areas of Alaska and similar places is slowly melting. This is causing major problems because the frozen ground was relied on for the support of many structures As the permafrost melts, the ground often turns into a soft bog that cannot support anything heavy. Although the permafrost does not melt quickly, as the average yearly temperature increases, it does eventually melt and structures begin to sink into the soft bog
The Trans Alaska Pipeline uses heat pipes in the support posts for the pipeline to prevent melting of the permafrost under the supports. This is successful but the heat pipes used are very expensive. The pipes that are described in this article are much less costly and can be made and installed by anyone with basic mechanical skills.
The heat pipes described here can refreeze the ground during the winter when very cold temperatures are common. If there is a heat pipe that penetrates deeply into the ground and extends above the ground, the above ground portion that is cooled by the extremely cold winter air will transfer the heat from deep underground and reduce the underground temperature around the pipe rapidly to the temperature of the air. To increase the efficiency of this process, the top of the heat pipe can be fitted with fins that help remove the heat. During the summer, the underground temperature will remain low because the pipe will not transfer heat down and the soil will insulate the subsurface frozen ground from the warm air above. The volume of the subsurface frozen region will increase over several seasons as the heat pipe continues to remove heat from deep below the surface.
The heat pipes described here are low in cost because they consist of nothing but a sealed pipe that has a small amount of propane or similar liquid in it. If the pipes are made of a metal that will not corrode, the pipes will last for many years. A large number of them can be used to protect, roads, buildings, or anything else that relies on permafrost for support.
Here is a simple technique to get the heat pipes into the frozen ground. Since the heat pipes are made from copper tubing, which is too soft to be driven into the ground directly, we can use a strong steel pipe to penetrate the ground. The steel pipe must be long enough to reach the necessary depth of the heat pipe. The pipe should have a pointed insert at the bottom end, which can be driven into the ground by the pipe. When the steel pipe reaches the depth desired, the copper tube can be inserted into the top of the pipe, and then the pipe can be extracted from the ground, leaving the pointed insert and the bottom of the copper tube both at the bottom of the hole that the pipe made in the ground. As the steel pipe is pulled out, the copper tube can remain stationery. It may be useful to pour sand down the pipe as it is being extracted so that the copper tubing will have good thermal contact with the walls of the hole made by the steel pipe. When the steel pipe is completely extracted, the copper tube will remain with one end buried as far as the steel pipe was driven, and the remainder of the length of the copper tube will be above ground and ready to be fitted with fins to help cool the ground deep below the surface. It will probably be necessary to provide some mechanical support and protection for the copper heat pipe and the heat-radiating fins near the ground surface.
Construction Hints
In order to keep costs down, the pipes should be constructed on site. A practical and economical method of construction is to use copper pipe filled with liquid propane up to the highest level where you want to absorb heat. The top of the pipe can have a common tire valve fitting to permit filling and sealing. Use a vacuum pump to remove air from the pipe then admit a pre-computed weight of propane. This weight can be found by multiplying the length of pipe that you want filled with propane by the cross sectional area of the pipe. This will give you the volume of liquid propane needed. Then multiply that volume (in liters) by 540 grams to get the weight of propane needed to fill the pipe. Start by weighing the propane tank on a scale then, using a flexible hose, start filling the pipe and stop when the scale shows that the desired weight of propane has entered the pipe. Any residual air can be removed by releasing a small amount of gas from the top of the pipe. Screwing a cap onto the valve can then securely seal the pipe. Since the propane is flammable, it would be best to keep the entire pipe outdoors so that in the event of a leak the propane would be safely dispersed to the atmosphere.
Most types of plastic pipe are unsuitable because the propane will slowly diffuse through the plastic and escape.
Propane would be suitable for use because the pressure that would be generated would be well within the capability of ordinary half to one inch copper pipe that can be assembled with sweat solder fittings using the common tin/antimony solder that is used in domestic water systems. The rated working pressure of ordinary one half to one inch copper tubing is around 500 PSI and the pressure of propane at 250 degrees F is about half that, so the heat pipe system has a good pressure safety factor. Keep in mind that the pressure in the system is determined by the temperature of the water in the pool and not by the temperature of the radiating surface at the top, so the propane pressure will never get very high. For more information about copper pipes see: http://www.copper.org/publications/pub_list/pdf/copper_tube_handbook.pdf
As for transferring a large amount of heat, this should not be a problem. Think of a common residential steam heating system. This operates with water as a working fluid but is otherwise similar. Many of these systems use a single pipe to carry the steam to radiators several floors above the boiler. The same pipe carries the liquid condensed water back to the boiler. This familiar system is capable of transferring the heat necessary to heat a house in very cold weather. It also contains nothing but liquid water and water vapor. In operation, the air has been eliminated by the automatic valves found at the radiators that vent air out of the system but close to prevent steam from escaping. If the descending liquid interferes with the rising gas, there are two symptoms that would indicate the problem. The first is that the temperature difference between the top radiator, and the heat source would increase, and the second one is that there may be audible gurgling sounds from the turbulent flow of condensate. There are two simple solutions to this problem. They are both often used in steam heating systems, the first is to use a large pipe for a single pipe system and the second is to provide a separate pipe for returning the liquid condensate to the boiler. Either of these solutions could be used in the heat pipe system described above, but will probably not be necessary because this system works slowly over a long time period and never needs to quickly transfer a lot of heat.
If the system is for use inside a residence, it would be preferable to use Freon as the working fluid to avoid any danger in case of leaking propane. This would work equally well but the cost of the Freon would be higher.
Labels: Free water chilling, fire protection, how heat pipes work, low cost air conditioning, preserving permafrost
Monday, October 04, 2010
memories of my brother
This is not a technological solution, but a more personal entry about my brother Conrad, who died May third 2010.
My Brother, Conrad OHO, made his living by modifying and repairing advanced bikes. His living space in an unheated garage exposed his values. The combination of his meticulously ordered tools and his political statements on practically every flat surface, along with the Spartan living space and lack of the "comforts of home," confirm the central driving force that guided my brother’s life.
I know that from childhood Conrad was always trying to live in a way that made the world better. We came from parents who had planned to spend their lives as missionaries in China, but WWII intervened. However, my parents did not give up on trying to fix the world, and Conrad got that passion, even though he rejected the religious part of the motivation for it.
There were times that Conrad tried to live in a commune of like minded people, but he was disappointed. He could never find one to live in with enough people who shared his values, his need for strict organization, his mechanical vision, and his way of doing things. And my brother was not good at compromise. Despite all of his efforts to join existing groups, or to start new ones, his attempts at living in a commune were unsuccessful.
But Conrad still longed for community, and he finally found a wonderful one in the people that he grew to love and trust among the bike lovers of the SF and the Marin County area. I only heard small bits of information about his community during my long phone talks with Conrad. Unfortunately, I did not know the depth of Conrad's engagement until after his death. I now see that he chose his friends well, and the mutual respect that was developed over the years is crystal clear. It makes me very happy to know that Conrad had such a wonderful group of people who shared his love of human powered transport, and who respected his mechanical elegance and his values. This community became his real family.
Conrad and I did not speak of family very much during our long phone conversations. We mostly spoke of alternative energy, politics, and nutrition. I fear that his intense interest in alternative nutrition and his avoidance of mainstream medicine did not serve him well, but there is now no way to be sure what really led to his death. I now have his autopsy report, and the doctor mentioned that, in addition to the ruptured aorta, he had hypertrophic cardiovascular disease. But, because he never got a conventional checkup, he did not know that his health was precarious. He had no insurance, and as a result, most all conventional medicine was priced at levels that he considered out of reach. As a result, he relied on his belief that if he got optimum nutrition, he would have optimum health.
Conrad did recognize that his hip was in terrible condition, but he did not want to get a hip replacement operation in this country because it would have bankrupted him. He investigated overseas operations, and he told me that he would eventually go that route if absolutely necessary. However, he first wanted to try restoring the structure and function of his hip with nutrition. He had told me that an x-ray showed very extensive damage, with no remaining cartilage and a seriously misshapen femur, so it seemed to me that the nutritional cure was hopeless. But the choice was Conrad’s and I will never know if his hip was improving because he died suddenly of a problem that he never knew he had.
After his death I met many of his close and valued community of friends and I have seen the qualities that Conrad grew to love. I understand the reasons that my brother trusted, and was trusted by this community. Even though I live far away from this community we share a love for Conrad and we share his passion for making the world a better place. I hope that we can grow close to each other over time and help to realize some of Conrad’s dreams.
Bill Isecke
There is a story of My and Conrad's growing up on a boat in the Harlem River in the Inwood section of NYC at http://gothamcenter.org/blotter/?p=96.
My Brother, Conrad OHO, made his living by modifying and repairing advanced bikes. His living space in an unheated garage exposed his values. The combination of his meticulously ordered tools and his political statements on practically every flat surface, along with the Spartan living space and lack of the "comforts of home," confirm the central driving force that guided my brother’s life.
I know that from childhood Conrad was always trying to live in a way that made the world better. We came from parents who had planned to spend their lives as missionaries in China, but WWII intervened. However, my parents did not give up on trying to fix the world, and Conrad got that passion, even though he rejected the religious part of the motivation for it.
There were times that Conrad tried to live in a commune of like minded people, but he was disappointed. He could never find one to live in with enough people who shared his values, his need for strict organization, his mechanical vision, and his way of doing things. And my brother was not good at compromise. Despite all of his efforts to join existing groups, or to start new ones, his attempts at living in a commune were unsuccessful.
But Conrad still longed for community, and he finally found a wonderful one in the people that he grew to love and trust among the bike lovers of the SF and the Marin County area. I only heard small bits of information about his community during my long phone talks with Conrad. Unfortunately, I did not know the depth of Conrad's engagement until after his death. I now see that he chose his friends well, and the mutual respect that was developed over the years is crystal clear. It makes me very happy to know that Conrad had such a wonderful group of people who shared his love of human powered transport, and who respected his mechanical elegance and his values. This community became his real family.
Conrad and I did not speak of family very much during our long phone conversations. We mostly spoke of alternative energy, politics, and nutrition. I fear that his intense interest in alternative nutrition and his avoidance of mainstream medicine did not serve him well, but there is now no way to be sure what really led to his death. I now have his autopsy report, and the doctor mentioned that, in addition to the ruptured aorta, he had hypertrophic cardiovascular disease. But, because he never got a conventional checkup, he did not know that his health was precarious. He had no insurance, and as a result, most all conventional medicine was priced at levels that he considered out of reach. As a result, he relied on his belief that if he got optimum nutrition, he would have optimum health.
Conrad did recognize that his hip was in terrible condition, but he did not want to get a hip replacement operation in this country because it would have bankrupted him. He investigated overseas operations, and he told me that he would eventually go that route if absolutely necessary. However, he first wanted to try restoring the structure and function of his hip with nutrition. He had told me that an x-ray showed very extensive damage, with no remaining cartilage and a seriously misshapen femur, so it seemed to me that the nutritional cure was hopeless. But the choice was Conrad’s and I will never know if his hip was improving because he died suddenly of a problem that he never knew he had.
After his death I met many of his close and valued community of friends and I have seen the qualities that Conrad grew to love. I understand the reasons that my brother trusted, and was trusted by this community. Even though I live far away from this community we share a love for Conrad and we share his passion for making the world a better place. I hope that we can grow close to each other over time and help to realize some of Conrad’s dreams.
Bill Isecke
There is a story of My and Conrad's growing up on a boat in the Harlem River in the Inwood section of NYC at http://gothamcenter.org/blotter/?p=96.
Friday, December 25, 2009
Solar water pasteurizer
High Output Solar Water Pasteurizer
There are more than a billion people who do not have reliable access to safe drinking water. These people are often disabled by waterborne diseases and become dependent on their community thus reducing the overall viability of the entire community.
The device described below is an improvement on most current devices used for solar water pasteurization because of the greatly increased quantity of water that can be made safe with a low input of solar heat and because its operation is automatic. The only attention required is keeping water in the input tank. The water is not boiled but merely heated to a temperature of at least 65 degrees C that will quickly kill any pathogenic organisms in it. The water is then cooled as its heat is transferred to the incoming water. The transfer of heat from the outgoing water to the incoming water is what permits the large increase in the amount of water that can be made safe.
This solar water pasteurizer can be made inexpensively using a thermostat, a metal cooking pot, copper tubing, insulation, and other low cost hardware. The thermostat can be the type that is used in automotive cooling systems. These are available in a choice of operating temperatures. The one that is used should be made for an operating temperature of at least 65 degrees C. if a higher temperature is used, the water will be more sterile, although it is generally agreed that 65 degrees C is sufficient for making the water safe. Be sure that the thermostat that is used closes completely at temperatures below its set temperature. Some thermostats have a small hole to permit a low flow at low temperatures. If there is such a hole, close it off. To connect the thermostat to the water feed tube, it is necessary to use an adapter to connect the small tube to the large flange that separates the two sides of the thermostat. A small funnel could be used or the top of an old spray can. The adapter can be soldered to the flange so that the incoming water must pass through the thermostat valve in order to get into the pot.
The water feed tank must be elevated above the level of the pot so that water will flow into the pot whenever the thermostat valve is open. The tank should be connected to the cooking pot by inexpensive 1/4 inch copper tubing. Inside the cooking pot the feed tube connects to the thermostat valve near the bottom of the pot that will open to admit water only when the temperature is high enough to pasteurize the water. The hot water output is taken from a tube that passes through the side of the pot near the top. This output water passes through another copper tube that is in close thermal contact with the tube carrying the water from the feed tank. The outgoing water must flow in the opposite direction from the incoming water. Binding the two tubes together with copper wire ensures that heat is easily transferred between the two tubes The incoming water is therefore heated by the hot water coming from the cooking pot.. This should be done for a distance that is sufficient for complete thermal transfer (the water in the two tubes should have reached very close to the same temperature). The pair of tubes must be insulated from the surrounding air to conserve the solar heat. Since the solar heat is recycled into the incoming water, the system can process much more water. The water enters the pot at almost the temperature that is necessary for pasteurization and needs very little additional heat. Thus, the output of safe water will be sufficient for many people. The feed tank can be made from any container that will hold enough water for an extended period of operation, To increase the minimum time that the water is kept heated, a series of baffles inside the cooking pot can control the path that the water takes from input to outlet. The cooking pot would be heated by sunlight in a solar stove. There are many very good designs for solar stoves to heat the cooking pot. Some require nothing more than a piece of glass, some aluminum foil, some black paint, and some corrugated cardboard from old boxes for insulation.
All of the materials needed for construction are inexpensive, readily available, and easily assembled with local labor. The major components of this system could be sold as a low cost kit for local assembly. To prevent the output water from becoming re-contaminated by airborne organisms care should be taken to keep contamination out. Use of a pressure cooker for the heated pot will keep contaminated air out, and is convenient because the cover will already have holes to connect the input and output tubes, and the cover will help transmit heat to the pot. Because heating the water will release dissolved air, be sure that the air can be vented without causing problems with the flow of output water. Eliminating any bends in the output tube that could trap air should be enough to avoid this problem. The reason that the thermostat is placed in the input feed line is because the thermostat can then compensate for changing water levels in the feed tank. This permits long periods of unattended operation.
This pasteurizer can be used indefinitely as there are no consumables, and no fuel is used. The flow rate is self-regulating. It automatically shuts down at night and adding mirrors to direct more sunlight to the solar stove can increase the output.
If the contaminated water source in not clear, then filter it through a piece of fabric to remove the particulates before putting it in the feed tank.
There are more than a billion people who do not have reliable access to safe drinking water. These people are often disabled by waterborne diseases and become dependent on their community thus reducing the overall viability of the entire community.
The device described below is an improvement on most current devices used for solar water pasteurization because of the greatly increased quantity of water that can be made safe with a low input of solar heat and because its operation is automatic. The only attention required is keeping water in the input tank. The water is not boiled but merely heated to a temperature of at least 65 degrees C that will quickly kill any pathogenic organisms in it. The water is then cooled as its heat is transferred to the incoming water. The transfer of heat from the outgoing water to the incoming water is what permits the large increase in the amount of water that can be made safe.
This solar water pasteurizer can be made inexpensively using a thermostat, a metal cooking pot, copper tubing, insulation, and other low cost hardware. The thermostat can be the type that is used in automotive cooling systems. These are available in a choice of operating temperatures. The one that is used should be made for an operating temperature of at least 65 degrees C. if a higher temperature is used, the water will be more sterile, although it is generally agreed that 65 degrees C is sufficient for making the water safe. Be sure that the thermostat that is used closes completely at temperatures below its set temperature. Some thermostats have a small hole to permit a low flow at low temperatures. If there is such a hole, close it off. To connect the thermostat to the water feed tube, it is necessary to use an adapter to connect the small tube to the large flange that separates the two sides of the thermostat. A small funnel could be used or the top of an old spray can. The adapter can be soldered to the flange so that the incoming water must pass through the thermostat valve in order to get into the pot.
The water feed tank must be elevated above the level of the pot so that water will flow into the pot whenever the thermostat valve is open. The tank should be connected to the cooking pot by inexpensive 1/4 inch copper tubing. Inside the cooking pot the feed tube connects to the thermostat valve near the bottom of the pot that will open to admit water only when the temperature is high enough to pasteurize the water. The hot water output is taken from a tube that passes through the side of the pot near the top. This output water passes through another copper tube that is in close thermal contact with the tube carrying the water from the feed tank. The outgoing water must flow in the opposite direction from the incoming water. Binding the two tubes together with copper wire ensures that heat is easily transferred between the two tubes The incoming water is therefore heated by the hot water coming from the cooking pot.. This should be done for a distance that is sufficient for complete thermal transfer (the water in the two tubes should have reached very close to the same temperature). The pair of tubes must be insulated from the surrounding air to conserve the solar heat. Since the solar heat is recycled into the incoming water, the system can process much more water. The water enters the pot at almost the temperature that is necessary for pasteurization and needs very little additional heat. Thus, the output of safe water will be sufficient for many people. The feed tank can be made from any container that will hold enough water for an extended period of operation, To increase the minimum time that the water is kept heated, a series of baffles inside the cooking pot can control the path that the water takes from input to outlet. The cooking pot would be heated by sunlight in a solar stove. There are many very good designs for solar stoves to heat the cooking pot. Some require nothing more than a piece of glass, some aluminum foil, some black paint, and some corrugated cardboard from old boxes for insulation.
All of the materials needed for construction are inexpensive, readily available, and easily assembled with local labor. The major components of this system could be sold as a low cost kit for local assembly. To prevent the output water from becoming re-contaminated by airborne organisms care should be taken to keep contamination out. Use of a pressure cooker for the heated pot will keep contaminated air out, and is convenient because the cover will already have holes to connect the input and output tubes, and the cover will help transmit heat to the pot. Because heating the water will release dissolved air, be sure that the air can be vented without causing problems with the flow of output water. Eliminating any bends in the output tube that could trap air should be enough to avoid this problem. The reason that the thermostat is placed in the input feed line is because the thermostat can then compensate for changing water levels in the feed tank. This permits long periods of unattended operation.
This pasteurizer can be used indefinitely as there are no consumables, and no fuel is used. The flow rate is self-regulating. It automatically shuts down at night and adding mirrors to direct more sunlight to the solar stove can increase the output.
If the contaminated water source in not clear, then filter it through a piece of fabric to remove the particulates before putting it in the feed tank.
Tuesday, November 10, 2009
Inexpensive Transport of Fresh Water
Inexpensive Transport of Fresh Water
Fresh water is scarce in many areas on the earth and some of them are located near oceans or large seas. This proposal describes a method for moving fresh water from places where it is plentiful on a seacoast to other places where it is needed. This would make use of the ocean for low cost transportation of fresh water to benefit large arid coastal areas. It would also permit raising crops in areas now too dry for agriculture.
The water would be moved in bulk inside floating bladders. For example, on the west coast of North America fresh water is plentiful in the north but scarce in the south. The California current flows south along the coast and could be used to assist in moving fresh water to southern California. A similar condition exists on the east coast of Australia. Southeast Australia now has a major drought and could use water from the north, which is plentiful.
The fresh water could be pumped into large bladders, which would float on the salt water of the ocean and could be moved south with minimal towing, as the current would do most of the work. After arrival at the destination, and pumping the fresh water into reservoirs on shore, the empty bladders could be returned for refill. For this plan to be economical, the bladders would have to be very large. For example, they could be made in the shape of sausages, perhaps 100 ft in diameter and 1000 ft long. Ten of these could be strung together and slowly towed. This would deliver 1805 acre-feet of water. Los Angeles has a severe water shortage and is now considering desalination with a projected cost of $1080 per acre-foot. The value of the water delivered on each trip of the bladders would therefore be $1,950,000. This method will become even more attractive compared to desalinization as the cost of fossil fuel energy increases. It also might substantially replace present energy intensive, less sustainable irrigation schemes such as the current practice of transporting electrically pumped water in canals and pipes running over mountains from the Sacramento River Delta region to the Los Angeles area.
The bladder material should probably be the same as is used for large tarps. I am thinking of the common ones based on a woven fabric of polypropylene cords covered on both sides with layers of polyethylene fused to the fabric. The plastics can have pigment and UV inhibitors included so they will be protected from solar exposure. Fabrication of the bladders is easy. Overlapping the material by an inch or so and fusing it with heat makes the seams. This works because polyethylene melts between 120 and 130 degrees C and polypropylene melts at about 160 C. The tarps are commercially available with the short edge measuring up to 100 ft so we know that rolls of the tarp material of that width and probably any arbitrary length should be available.
Strong, durable, and inexpensive sausage shaped bladders can be constructed of this material. The material can be tapered down as the ends of the bladders are approached and finally clamped tightly to a large pipe fitting with a valve and coupling so that the bladders can be filled, emptied and coupled to each other for transit.
The bladders could be inexpensively made very strong to survive the inertial forces involved in starting, turning and stopping them. The force of surging water due to the effects of inertia or rogue waves could be absorbed by elastic bands around the bladders near the ends. They should not be much affected by stormy weather because if they were not tightly filled, they would be transparent to the waves in the ocean, which would pass through them with little effect.
As they would be moving very slowly relative to the water around them, and the fabric that they are made from will not be tightly stretched, they would yield when contacted and gently push aside any debris that they encountered on the water surface. If there is a problem with floating debris damaging the bladders, they could be protected by using old carpets as fenders along the water line of the bladders. A mast with a flashing light and radar reflector could be mounted at the end of each bladder to warn boat traffic away.
For the particular case of delivering water to southern California, In order to get large quantities of fresh water without political problems, I think that it may be necessary to go further north than the California border to get the fresh water. The Columbia River is fed by the runoff from the Canadian Rockies and a large fraction of its fresh water flows into the pacific. The US Army corps says that the average annual runoff of this river is 198,000,000 acre-feet. The amount taken for southern California would be a very tiny fraction of that. Where the Fraser River flows into Puget Sound at Vancouver BC Canada is another possible source. The small amount transported could be very significant for southern California or western Mexico. There is a lot more water available further north from other rivers that could also be used. The transit time would be longer, but the current would still do most of the work.
This scheme could possibly be used for water delivery to any arid coastal area. For example, the south and east coasts of the Mediterranean Sea are arid and the north and west coasts have adequate water. The effects of global warming seem to be reducing the rainfall on the south Mediterranean coast and northern Africa, but increasing it in Europe so it seems that that the need and supply situation will improve with time. In regions such as this, where there is little natural current to assist in the movement of the bladders, a very energy efficient method of moving them would be to use a very long cable that would be pulled from a fixed point. This fixed point could be a ship that is anchored. The long cable would pull the bladder up to the ship using a winch. The ship would then move to a new anchor point, while paying out the cable, then pull the cable in again. This would necessitate following a route with water shallow enough to anchor, usually near a shoreline.
This would obviously need considerable investment capital because the design and construction of the large bladders and construction of the necessary shore facilities for filling and emptying the bladders would be costly. However, the facilities and materials would be reusable and should have a long useful life. There would be necessary political connections, commitments, and payments for the system to function. However, the high value and need for the fresh water delivered should result in a large economic gain despite the start-up costs,
Increasing the size of the bladders should be cost effective as the amount of material needed and the energy required for towing increases more slowly than the capacity of the bladders. There would be a practical limit on size because of the need to transport the empty bladders back for refill. Carrying them on a ship or barge would probably be more efficient than towing the empties, but that may depend on local conditions.
This idea will increase in value with time because of the continuing depletion of the aquifers in many arid but highly populated seacoast regions. Fresh water will become increasingly scarce and desalination is very energy intensive and is becoming more costly as oil and gas are depleted
There are other economic and political considerations. In my opinion, the sale of the water to private companies could result in very undesirable consequences. Privatization of water systems in many areas has resulted in large increases in rates, government corruption, and compromise of public safety. The question of who should own the water is an important consideration that must not be ignored. The water is a natural resource that is owned by the citizens and they should pay for the operation of the distribution system but not for the water itself. The way to structure the transport deals should be for the government agencies involved to deal directly with each other. They could hire contractors to do the work of transporting the water, but should never sell the water to a private company. The price that users pay may need to be set higher than the cost of transport and distribution in order to limit consumption to the amount of water available, but the excess income in this case should go to the general funds of the governments involved, and not to corporate profit.
Another consideration is that the level of fresh water removal from a source river system should be kept low enough that there would be no significant effects on the natural biological systems of the river and so that there is enough extra water available to permit a considerable increase in local consumption without the necessity of reducing the amount of water provided to the receiving area, which may be expected to become dependent on its continued availability. The rate of extraction and transport of fresh water will need to vary seasonally according to the rate of river flow and therefore the water storage at the delivery point must be large enough so that the rate of consumption can remain reasonably constant. It may be that the bladders can be economically used for storage as well as transportation. The costs of this transportation system are not small, but the energy requirements are low. Operating the system will create many jobs. The alternative sources of fresh water such as desalinization are still more costly and have large energy requirements with much greater climate change consequences.
With the help of several people on a web based discussion group, I have found out that there have been previous attempts to transport water with similar technology. I had difficulty finding out about the previous activity because what I was calling bladders, they referred to as Medusas the most advanced operation was by Nordic Water Supply ASA, which transported water from Turkey to Cyprus. Unfortunately, due to some equipment failures and other problems, this company, after operating since 1994 declared bankruptcy in May of 2003. I believe that there have been other small-scale operations in the Mediterranean area, some of which may still be operating. Due to the length of time that this sort of operation has been in operation or attempted, it seems likely that there are no patent related obstacles to further development. Perhaps now, with the greater economic need, and using some of the ideas described above, there can be some successful large-scale applications of this system.
I have done some daydreaming about other uses for the tarp material, not just transportation, but storage. The one with the most potential seems to be the creation of artificial lakes in areas where the rainfall is very seasonal. For example, the regions where there are seasonal monsoon rains with lots of water available, in fact, way too much during the rainy season, so that there are disastrous floods with loss of life and property.
In regions that are mostly flat, such as Bangladesh, (which is barely above sea level), it seems that a good plan would be to start in the beginning of the dry season, excavate a large area, as deeply as possible, use the removed material to raise the level of the surrounding area, then surround the excavation with a high levee and line the bottom of the new lake with impermeable material such as the tarp fabric.
When the rains come, use massive pumps to fill the lake with water from the swollen rivers. This avoids the usual flooding for two reasons: one is that the area in now higher because of the material removed to make the lake, and the other reason is that the excess river water was pumped into the lake which should be filled to the top of the levees, and will now have a level well above the surrounding land. During the following dry season, the lake water is used for irrigation and other needs. The lake can be stocked with fish, such as tilapia, so that it will be productive of food as well.
Obviously, this is not a cheap project. It requires massive earth moving equipment, massive pumps, and the energy to run them. However, it may be cheap compared to the cost of not doing it and also considering the increased year round agricultural production that it makes possible. The elevated land will also provide protection during the periodic cyclones (hurricanes) that flood the land with seawater and often cause major loss of life due to drowning. Even if the raised land is not high enough to avoid flooding in the storm, the levees will be much higher and can be topped with concrete storm shelters for the local population.
I don't know if any of this is politically possible, or where, but I can dream…
Bill Isecke
bisecke@gmail.com
1 201 836 8403
Fresh water is scarce in many areas on the earth and some of them are located near oceans or large seas. This proposal describes a method for moving fresh water from places where it is plentiful on a seacoast to other places where it is needed. This would make use of the ocean for low cost transportation of fresh water to benefit large arid coastal areas. It would also permit raising crops in areas now too dry for agriculture.
The water would be moved in bulk inside floating bladders. For example, on the west coast of North America fresh water is plentiful in the north but scarce in the south. The California current flows south along the coast and could be used to assist in moving fresh water to southern California. A similar condition exists on the east coast of Australia. Southeast Australia now has a major drought and could use water from the north, which is plentiful.
The fresh water could be pumped into large bladders, which would float on the salt water of the ocean and could be moved south with minimal towing, as the current would do most of the work. After arrival at the destination, and pumping the fresh water into reservoirs on shore, the empty bladders could be returned for refill. For this plan to be economical, the bladders would have to be very large. For example, they could be made in the shape of sausages, perhaps 100 ft in diameter and 1000 ft long. Ten of these could be strung together and slowly towed. This would deliver 1805 acre-feet of water. Los Angeles has a severe water shortage and is now considering desalination with a projected cost of $1080 per acre-foot. The value of the water delivered on each trip of the bladders would therefore be $1,950,000. This method will become even more attractive compared to desalinization as the cost of fossil fuel energy increases. It also might substantially replace present energy intensive, less sustainable irrigation schemes such as the current practice of transporting electrically pumped water in canals and pipes running over mountains from the Sacramento River Delta region to the Los Angeles area.
The bladder material should probably be the same as is used for large tarps. I am thinking of the common ones based on a woven fabric of polypropylene cords covered on both sides with layers of polyethylene fused to the fabric. The plastics can have pigment and UV inhibitors included so they will be protected from solar exposure. Fabrication of the bladders is easy. Overlapping the material by an inch or so and fusing it with heat makes the seams. This works because polyethylene melts between 120 and 130 degrees C and polypropylene melts at about 160 C. The tarps are commercially available with the short edge measuring up to 100 ft so we know that rolls of the tarp material of that width and probably any arbitrary length should be available.
Strong, durable, and inexpensive sausage shaped bladders can be constructed of this material. The material can be tapered down as the ends of the bladders are approached and finally clamped tightly to a large pipe fitting with a valve and coupling so that the bladders can be filled, emptied and coupled to each other for transit.
The bladders could be inexpensively made very strong to survive the inertial forces involved in starting, turning and stopping them. The force of surging water due to the effects of inertia or rogue waves could be absorbed by elastic bands around the bladders near the ends. They should not be much affected by stormy weather because if they were not tightly filled, they would be transparent to the waves in the ocean, which would pass through them with little effect.
As they would be moving very slowly relative to the water around them, and the fabric that they are made from will not be tightly stretched, they would yield when contacted and gently push aside any debris that they encountered on the water surface. If there is a problem with floating debris damaging the bladders, they could be protected by using old carpets as fenders along the water line of the bladders. A mast with a flashing light and radar reflector could be mounted at the end of each bladder to warn boat traffic away.
For the particular case of delivering water to southern California, In order to get large quantities of fresh water without political problems, I think that it may be necessary to go further north than the California border to get the fresh water. The Columbia River is fed by the runoff from the Canadian Rockies and a large fraction of its fresh water flows into the pacific. The US Army corps says that the average annual runoff of this river is 198,000,000 acre-feet. The amount taken for southern California would be a very tiny fraction of that. Where the Fraser River flows into Puget Sound at Vancouver BC Canada is another possible source. The small amount transported could be very significant for southern California or western Mexico. There is a lot more water available further north from other rivers that could also be used. The transit time would be longer, but the current would still do most of the work.
This scheme could possibly be used for water delivery to any arid coastal area. For example, the south and east coasts of the Mediterranean Sea are arid and the north and west coasts have adequate water. The effects of global warming seem to be reducing the rainfall on the south Mediterranean coast and northern Africa, but increasing it in Europe so it seems that that the need and supply situation will improve with time. In regions such as this, where there is little natural current to assist in the movement of the bladders, a very energy efficient method of moving them would be to use a very long cable that would be pulled from a fixed point. This fixed point could be a ship that is anchored. The long cable would pull the bladder up to the ship using a winch. The ship would then move to a new anchor point, while paying out the cable, then pull the cable in again. This would necessitate following a route with water shallow enough to anchor, usually near a shoreline.
This would obviously need considerable investment capital because the design and construction of the large bladders and construction of the necessary shore facilities for filling and emptying the bladders would be costly. However, the facilities and materials would be reusable and should have a long useful life. There would be necessary political connections, commitments, and payments for the system to function. However, the high value and need for the fresh water delivered should result in a large economic gain despite the start-up costs,
Increasing the size of the bladders should be cost effective as the amount of material needed and the energy required for towing increases more slowly than the capacity of the bladders. There would be a practical limit on size because of the need to transport the empty bladders back for refill. Carrying them on a ship or barge would probably be more efficient than towing the empties, but that may depend on local conditions.
This idea will increase in value with time because of the continuing depletion of the aquifers in many arid but highly populated seacoast regions. Fresh water will become increasingly scarce and desalination is very energy intensive and is becoming more costly as oil and gas are depleted
There are other economic and political considerations. In my opinion, the sale of the water to private companies could result in very undesirable consequences. Privatization of water systems in many areas has resulted in large increases in rates, government corruption, and compromise of public safety. The question of who should own the water is an important consideration that must not be ignored. The water is a natural resource that is owned by the citizens and they should pay for the operation of the distribution system but not for the water itself. The way to structure the transport deals should be for the government agencies involved to deal directly with each other. They could hire contractors to do the work of transporting the water, but should never sell the water to a private company. The price that users pay may need to be set higher than the cost of transport and distribution in order to limit consumption to the amount of water available, but the excess income in this case should go to the general funds of the governments involved, and not to corporate profit.
Another consideration is that the level of fresh water removal from a source river system should be kept low enough that there would be no significant effects on the natural biological systems of the river and so that there is enough extra water available to permit a considerable increase in local consumption without the necessity of reducing the amount of water provided to the receiving area, which may be expected to become dependent on its continued availability. The rate of extraction and transport of fresh water will need to vary seasonally according to the rate of river flow and therefore the water storage at the delivery point must be large enough so that the rate of consumption can remain reasonably constant. It may be that the bladders can be economically used for storage as well as transportation. The costs of this transportation system are not small, but the energy requirements are low. Operating the system will create many jobs. The alternative sources of fresh water such as desalinization are still more costly and have large energy requirements with much greater climate change consequences.
With the help of several people on a web based discussion group, I have found out that there have been previous attempts to transport water with similar technology. I had difficulty finding out about the previous activity because what I was calling bladders, they referred to as Medusas the most advanced operation was by Nordic Water Supply ASA, which transported water from Turkey to Cyprus. Unfortunately, due to some equipment failures and other problems, this company, after operating since 1994 declared bankruptcy in May of 2003. I believe that there have been other small-scale operations in the Mediterranean area, some of which may still be operating. Due to the length of time that this sort of operation has been in operation or attempted, it seems likely that there are no patent related obstacles to further development. Perhaps now, with the greater economic need, and using some of the ideas described above, there can be some successful large-scale applications of this system.
I have done some daydreaming about other uses for the tarp material, not just transportation, but storage. The one with the most potential seems to be the creation of artificial lakes in areas where the rainfall is very seasonal. For example, the regions where there are seasonal monsoon rains with lots of water available, in fact, way too much during the rainy season, so that there are disastrous floods with loss of life and property.
In regions that are mostly flat, such as Bangladesh, (which is barely above sea level), it seems that a good plan would be to start in the beginning of the dry season, excavate a large area, as deeply as possible, use the removed material to raise the level of the surrounding area, then surround the excavation with a high levee and line the bottom of the new lake with impermeable material such as the tarp fabric.
When the rains come, use massive pumps to fill the lake with water from the swollen rivers. This avoids the usual flooding for two reasons: one is that the area in now higher because of the material removed to make the lake, and the other reason is that the excess river water was pumped into the lake which should be filled to the top of the levees, and will now have a level well above the surrounding land. During the following dry season, the lake water is used for irrigation and other needs. The lake can be stocked with fish, such as tilapia, so that it will be productive of food as well.
Obviously, this is not a cheap project. It requires massive earth moving equipment, massive pumps, and the energy to run them. However, it may be cheap compared to the cost of not doing it and also considering the increased year round agricultural production that it makes possible. The elevated land will also provide protection during the periodic cyclones (hurricanes) that flood the land with seawater and often cause major loss of life due to drowning. Even if the raised land is not high enough to avoid flooding in the storm, the levees will be much higher and can be topped with concrete storm shelters for the local population.
I don't know if any of this is politically possible, or where, but I can dream…
Bill Isecke
bisecke@gmail.com
1 201 836 8403
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