WO2000024487A1

WO2000024487A1 - Water condensation system

Info

Publication number: WO2000024487A1
Application number: PCT/US1999/024800
Authority: WO
Inventors: William S. Malson; Louis Rosberg
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-10-23
Filing date: 1999-10-22
Publication date: 2000-05-04
Anticipated expiration: 2001-04-23
Also published as: AU1598400A; WO2000024487B1

Abstract

A water condensation system including a water vapor retaining container (12), a condenser (22), located within the water vapor retaining container for containing a liquid at a lower temperature than the water vapor and a collection trough (23) under the condenser for gravitationally collecting the condensate which has sweated off the condenser. The greatest application is to remove water from the air in semi-arid to humid environments, such as a large dehumidifier, removing pure water directly from the air.

Description

WATER CONDENSATION SYSTEM

Pure water is necessary for life as we know it. However, there is an enormous difference between potable, or drinking water, and available sources of water. As anyone knows, there are essentially three types of water in the world: fresh water, salt water, and brackish water. Mankind has contaminated all three types of water so that he cannot drink it. Therefore, water purification has played a huge roll in the advancement of mankind. Geographic boundaries have become important due to the water that is contained therein. The Israeli-Arab War is largely being fought over a fresh water supply.

As a matter of fact, it has been postulated by ex-president Jimmy Carter and ex-senator Paul Simmon in their book "Tapped Out" that all the wars that will be fought in the next fifty years will be fought over fresh water supplies. Recent developments in the news show that foreign countries wish to buy fresh water from Lake Superior in Northern Michigan. Great controversies have arisen over water supplies and the ability to have fresh water. Only three percent of the world's water supply is fresh water. Salt water and brackish water need to be distilled, put through reverse osmosis or a number of other conventional methods of water purification.

Traditionally, desalination of water has included various methods, including flash distillation which uses relatively large amounts of energy, or reverse osmosis which generates a large amount of waste water discharge. There are many countries in the world that derive their entire source of water through these purification methods. Both of these methods require a lot of energy and a great deal of water. As one can imagine, flash distillation or any other kind of distillation yields a relatively low amount of water when compared to the amount of energy that is required to produce it. Salt water can be distilled and potable water can be collected, although the use of a nearly equivalent amount of oil is needed to fuel the distillation process. collected, although the use of a nearly equivalent amount of oil is needed to fuel the distillation process.

With regards to reverse osmosis, it is well known that the procedure requires a nearly four to one ratio of unpurified water to purify water. This means that a concentrated brine solution is returned to the water supply, which will forever change the ecological balance in the neighboring environment. For this reason, reverse osmosis needs to be used near a main body of water so that the waste water discharge can return to the original source at a dilution ratio which will not effect the ecology of the system. Due to this enormous amount of discharge, reverse osmosis will change the electrolytic balance of an ecology, thereby changing the structure of fishing and other wild life near the shore. Currently, reverse osmosis is used near the Red Sea, the Mediterranean Sea, and other large areas without tides. This compounds the problem because the dumping of the waste water discharge cannot be washed away with the tide and diluted.

Currently, large water purification freighters containing reverse osmosis units are placed in International Waters by various countries so that the dumping of the waste water discharge which is produced by reverse osmosis is done in an off shore place, where the laws do not require the ecological imbalance to be checked.

Naturally, different water environments exist throughout the world. These conventional water purification systems will find application throughout the world in areas where there is a large main body of water where it can dilute contaminants being ejected from the system. However, there will be many shoreline and inland applications which cannot support the large amount of contaminated discharge which is being produced by the reverse osmosis systems. These applications require some sort of distillation installation. Traditional distillation methods have included flash distillation, discussed above, in which large amounts of energy are used to take any type of water and purify it into potable water. Distillation is appropriate in shoreline and inland applications because the discharge that reverse osmosis generates will change the ecological balance as discussed above. Distillation systems produce pure water in addition to a sludge which can be disposed of in landfills appropriately. However, distillation methods use a great deal of energy. Where the energy comes from is dependent upon the distillation system itself. Needless to say, low cost desalination is the ultimate goal of any water purification system. Another goal of water purification systems is to manage the waste which is being generated, or actually separated from, the process.

Therefore, it would be a great advantage to provide a potable water generation system which requires little non-renewable energy for carrying out its process, while as well as managing the waste which is generated therefrom in an ecologically manageable manner. It would be most advantageous if a solar distillation system having a high throughput could be available.

SUMMARY OF THE INVENTION

In accordance with the present invention there is disclosed a condensation water purification system having low energy requirements. In its most basic essence, it is a large dehumidifier for removing humidity from the air to produce pure water. This preferred embodiment includes a large dehumidifier air-to-water unit which includes a passive solar air-tight container for retaining water vapor which is produced therein through the use of solar energy and/or heat retained through solar energy, stored and then reintroduced into the condensation unit, or geothermal energy, or any other naturally occurring energy which may be put into this condensation system.

In its most basic form there is a condenser pipe contained within the water vapor container. This condenser has a refrigerated liquid, such as water, at a relatively cooler temperature than the water vapor, which causes "sweating" of the condenser pipe, much like a cold drink in a glass "sweating" on a hot day. This imitates the hγdrological cyle found in nature, where rain condenses and falls down, and then evaporates again into the clouds. Another common example, this naturally occuring phenomenon acts much like a cold drink in a glass "sweating" on a hot day. Anyone who has had a cold drink on a hot day has experienced the "sweating" which generates the purified water of this system. The present invention also generates this "sweated" water and drips it into a collection trough located under the condenser pipe which is designed to collect all the condensed water which has sweated off the condenser pipe.

This natural phenomenon is encouraged and accelerated with the present invention. It occurs on a large scale, if desired, in semi-arid to humid climates which have no ready supply of potable water. The western bank of Saudi Arabia is such a place where the humidity is generally on the order of from about 70 to about 90%, although the only water for drinking is salt or brackish water. In such semi-arid to humid locals throughout the world, there is a sufficient amount of water vapor in the air to be dehumidified and generate purified water through the present invention.

Preferably, the present invention is embodied in an elongated darkly colored air-tight container into which air is allowed with a high water vapor content. Water can be introduced into the bottom of this container, so that there is a ready supply of water vapor. Running through the length of the elongated air-tight container is a condenser pipe preferably made of copper which is located near the top of the airtight container. A collection trough is located directly underneath the condenser pipe and is tilted to allow gravity to carry the collected water to the end of the airtight container. Greater detail will be discussed hereinbeiow. Therefore, a water purification system is disclosed which achieves the advantages of solar distillation system while taking the water directly from the air or from the environment which is created within an air-tight container.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 is a perspective view of the overall system in situ; FIGURE 2 is a side elevational view of an inground embodiment of the present invention;

FIGURE 3 is a side elevational view of the core essence of the invention; FIGURE 4 is a top view showing the inner construction of the large embodiment of the passive solar field;

FIGURE 5 is a perspective view detailing the relative placement of the condenser pipe, the collective trough, the trough collection pipe and the manifold; and

FIGURE 6 is a top plan view of the closed loop condenser pipe system utilized in the large area condensation system.

DETAILED DESCRIPTION OF THE DRAWINGS

In accordance with the present invention, FIGURE 1 shows the overall view of one embodiment of the present invention incorporating passive solar energy as the energy means input. The passive solar condensation system is shown with its many options. As can be seen, filter 54 is a water intake from the source water supply and is pumped, by pump 52, into pre-treatment retention pond 56 initially. The source water may be brackish or may contain oil or other such contaminants such that filter 54 shall initially separate out the large particulates, i.e. fish, seaweed, logs, sand and grit.

Retention pond 56 shall be used to pretreat water from the source, removing oil. or any other impurity that will contaminate the interior of the solar containbers.

In the event that source water is brackish or oily, the oil can be removed partially from the water by filter 56. This water is then pumped, by pump 52, into the passive solar field 10, shown having numerous "cells" 12.

In this embodiment, each cell 12 is preferably over 200 feet long and the inside of each cell is further described herein below with respect to FIGURES 2 through 4. The clean water is collected and pumped via pump 60 into storage tanks 75. The super salty water which is the by product of the evaporation and condensation operation is pumped into brine pond 70. Brine pond 70 will contain

"clean" brine water which has a very high concentration of salt. The brine pond

70 may be used to store solar energy in the salt contained in the solution for operation drain nighttime hours when solar energy is not available. As one may realize, salt has a high thermal capacity, which is why a sandy beach is so incredibly hot to the bottom of your foot when walking on a sunny day on a beach.

At nighttime, this heated, super salty water can be pumped back into the cells 12 in order to cause a greater water vapor content within cell 12 to increase the likelihood of condensation.

Still referring to FIGURE 1 , there is showing an optional geothermal tank 68 which can be used to preheat the water used within cell 12 to cause greater vapor pressure, and therefore greater concentration of condensate. This geothermal option is obviously only helpful in areas where a geothermal source of heat is present.

Passive solar field 12 will essentially act as a large scale dehumidifier which will utilize 1 /3 of the energy requirement of a distillation apparatus, while producing approximately two to three times of a distillery. Consequently, it is hoped that this system moves toward a low cost desalination plant, as well as a plant that does not create an ecological imbalance.

It is also recommended that warm water be "pulsed" into cell 12 so that the water has an opportunity to heat up in situ. If the water was constantly flowing, under most conditions, it would take a greater amount of thermal energy to vaporize the water within cell 12. If the intake water is "pulsed" into cell 12, enough time will be allowed between "pulses" to allow the water to vaporize within the cell.

Referring next to FIGURE 2, there is shown another embodiment of the present invention in which a plurality of the condensing tubes in a plurality of the condensing tubes are placed within a pit in the ground having a waterproof liner to hold the liquid. A liner 1 1 is shown on the floor of the pit having a bottom dimension of 18 and a side wall vertical dimension of 1 2. Side walls 13 are held in place by side wall stakes 14. Liner 18 is shown held in place by berm 28. Liner 18 also has a liner top cover 26 to prevent evaporation into the air of the liquid within the pit. Cable 21 helps to hold down the liner top cover so that when wind creates a low pressure center it will not fly up, and another set of cables 21 are placed underneath the top in a perpendicular fashion as is more clearly shown in FIGURE 3.

The essential portions of the water condensation system includes condensers 22 which sit on top of condenser collection troughs 23. As the water "sweats" off the condenser it is collected in collection manifold 24 through trough collection pipe 25 into manifold 24. Note that manifold 24 is tipped downwardly such that the water which is collected in manifold 24 will be urged by gravity into storage tank 68. Storage tank 68 stores the "clean end " water, while sediments, such as brine or other solids are discharged through pipe 17. Water intake line 16 from the pump as shown in FIGURE 2 feeds the condensers 22 with cool water.

The cold water may be refrigerated by many different means including circulation through heat exchangers and cold ocean water, through actual refrigeration units, through reverse geothermal effects, through ice water, or any other known means for refrigerating a liquid. Furthermore, Freon may be circulated through condenser 22, as well as other known refrigerants.

It is suggested that the refrigerated liquid may be "pulsed" into condensers

22 to maximize the "sweating" of the condensers. The height adjustment of the condensers 22 are enabled by adjustable supports 19 for the cooler and the condensate lines. In this embodiment of the present invention, the passive solar field can extend over an acre in size to collect approximately 90 to 100 gallons per hour in un-optimized conditions. Unpurified water is placed in the bottom of the pit liner 18 such that as solar energy heats the cavity within, the water evaporates and creates a water vapor pressure at the top of the pit near the condensers. Chilled water was run through condenser 22 in an either continuous or pulsed fashion to optimize sweating of condenser 22. The water is collected in condensate collection trough 23 and the trough 23 is inclined so that gravity allows the collected water to travel through trough collection pipe 25 into manifold 24 which is then, again, tipped downwardly to fall into the storage tank.

It is also envisioned that hot super-saturated brine water can be pumped out of a field in the nighttime after it has absorbed solar energy all day long. Due to the heat of this system, a water vapor concentration will be established in the top of the pit and liner and condensate will form and be collected. This invention envisions many ways of heating the water, including solar energy, salt brine heat capacity heating, geothermal heating, or any other naturally occurring for method for creating heat. The chilled water which is run through the condenser may be chilled through any means. This unit could be placed near the edge of a large body of water as shown in FIGURE 1 . However, it may also be formed in a large floating farm to be placed in the middle of the ocean.

Looking now to FIGURE 3, there is shown the functioning portion of a cell in accordance with the present invention. Condenser 22 is a tube or pipe, preferably a copper plumbing pipe to aid in the sweating action, located over a trough 23 for collecting the sweated water. As discussed before, cell 12 is a water tight container holding the liquid 50 in the bottom. The sunlight comes in through the top of cell 12 and heats the liquid 50, increasing the vapor pressure in the uppermost portion of the cell. Our experiments have shown that on a 75°F day in southern Michigan, the temperature at the top of the cell was about 160°F, while the water being run through the condenser was approximately 45°F. This set of circumstances produced a optimum amount of water.

When ocean water was used as liquid 50 and Detroit City water was used as the cooled liquid going through condenser 22, and the interior temperature of the cell was 140°F, while the Detroit City water was at 40°F, 9 gallons of condensed water were made in an 18 hour period. The ocean water initially had a contamination of 30,000 PPM, and the water which was collected from sweating off the condenser pipe was produced at 8 PPM. The experimental cell was 10 feet long, 1 foot tall and 1 foot wide. Scaling up the size of the cell only appears to create more water, not more problems. For a reference, anything less than 500 PPM is considered potable water by the World Health Organization and by EPA regulations, and anything less than 10 PPM is considered distilled by the US Distillation Association.

Still looking at FIGURE 3, it shall be noted that liquid 50 can be contaminated fresh water, salt water, brackish water, or any other liquid from which water vapor can be created. In essence, cell 12 acts as a dehumidifier when there is a high concentration of water vapor in the cell which condenses on the outside of condenser pipe 22. Other possible embodiments may include the use of a refrigerant liquid running through condenser 22, such as Freon, TFE, or other refrigerant liquids known in the art.

Referring back to FIGURE 2, liquid 50 may be a high salt content water solution which has been storing solar energy during the sunlight day hours, and may be pumped into cell 12 at nighttime in order to bring a heated aqueous solution into the cell. If liquid 50 is on the order of 120°F. and is pumped into cell 12, the water will evaporate into the air within cell 12 causing a high water vapor concentration 40. If a cooled liquid is flowed through condenser 22, water production can continue in the nighttime. As discussed above, any source of heat, whether is be from the salt, geothermal, electric, gas furnace, whatever may be utilized.

Cell 12 may be made of any dark plastic or metal in order to absorb sunlight energy. The bottom liner of cell 12 should be of a waterproof material so that liquid 50 will not leak out. Condenser pipe 22 may be made of any suitable material, such as copper pipe or aluminum pipe, or a highly thermally conductive plastic, but convention and economy dictate the used of copper piping. Trough 23 may be made of any suitable material, but is preferably made of plastics so as not to transfer any thermal energy. Insulative plastics are especially interesting. Collection trough pipe 25 and manifold 24 may be made of any suitable material, as their function is to transfer the liquid only. Referring next to FIGURE 4, there is shown a top view of a portion of a large cell. In this embodiment, condensers 22 run longitudinally and the cell is covered by a top liner cover 26, shown in a tear-away view. Cables 21 run perpendicular to one another from underneath and on top of the cover. Condensers 22 are shown in a closed loop configuration by being connected to end pipe 30. The refrigerant coolant liquid is run through pipe 30 back to either a refrigeration unit or back down into a heat exchanger circulating in the depths of the ocean, or any other way of refrigerating that liquid. Cell 12 has side walls 13 which are held up by side wall stakes 14 and they have temperature probes 35 extending therein. The collection troughs 23 are not shown in this illustration.

Looking now to FIGURE 5, there is a perspective view of a cutaway showing the cell of FIGURE 3. Condenser 22 is shown located over collection trough 23 with brackets holding collection trough 23 underneath. More brackets hold collection trough 23 up against a board which is attached to the top of the cell. The manifold 24 for collecting the fresh water is attached to trough 23 by collection trough pipe 25. Top cover 26 is a laminated woven plastic material which is sealed around the outside of cell 12. Bottom plastic liner 61 can be made of a rigid plastic, or can be made of a soft pliable plastic being supported with rigid side walls which may be separate.

FIGURE 6 shows the closed loop configuration for the refrigerated liquid running through condensers 22 and end pipes 30. The flow of the liquid is shown entering into the system and circulating therethrough before exiting. Water enters through inlet 70 circulates through condensers 22 and end pipes 30 and exits the closed loop system through fixture 74. Block 72 prevents the flow of water except in one direction. The refrigerated liquid entered inlet 70 may be coming from any source of cool liquid.

Therefore, in accordance with the objectives and advantages described above, the above described water condensation system can supply purified, drinking water to nations where drinking water is hard to come by. With the exception of expensive reverse osmosis and distillation systems, certain regions and nations in the world do not have sufficient money to purchase systems and operate them for purified water. This system is an inexpensive, highly effective and high capacity one in which replacement parts are few, maintenance is slight, and energy costs are minimal. The scope of the invention is to be limited only by the claims which are appended hereto.

INDUSTRIAL APPLICABILITY

The present invention finds industrial applicability in the production of water in semi-arid to humid locations where fresh water is not easily available. One of the embodiments of the present invention is designed to use solar energy to produce potable water by collecting condensate.

Claims

What is claimed is: 1 . A water condensation system, comprising: a water vapor retaining container; a condenser located within the water vapor retaining container for containing a liquid at a lower temperature than the water vapor, such that condensate forms on the outside of the condenser when water vapor is present and lower temperature liquid is in the condenser; and a collection trough under the condenser for gravitationally collecting the condensate which has sweated off the condenser.

2. The water condensation system of claim 1 , wherein the water vapor retaining container is a passive solar system.

3. The water condensation system of claim 1 , wherein the water vapor retaining container is airtight.

4. The water condensation system of claim 1 , wherein the condenser is made of pipe.

5. The water condensation system of claim 4, wherein the condenser is made of a closed loop system of pipes.

6. The water condensation system of claim 4, wherein the condenser is made of a pipe material selected from the group consisting of copper and aluminum.

7. The water condensation system of claim 1 , wherein the condenser is longitudinally oriented within an elongated water vapor retaining container.

8. The water condensation system of claim 1 , wherein the container is an elongated container having dimensions of from about 6 inches to about 18 inches in height, and from about one (1 ) foot to about 20 acres in width and from about two feet to about 20 acres in length.

9. The water condensation system of claim 1 , wherein the condenser carries a liquid selected from the group consisting of water, fresh water, salt water, refrigerant, and supercooled gases.

10. The water condensation system of claim 1 , wherein the liquid in the condenser is at a temperature of less than about 45°F.

1 1 . The water condensation system of claim 1 , wherein the liquid in the container is at a temperature of greater than about 100°F.

12. The water condensation system of claim 1 , wherein the collection trough is of a V-shaped configuration.

13. The water condensation system of claim 1 , wherein the condensate being collected is water having less than about 500 ppm impurities.

14. A passive solar water condensation system for processing non-potable water into potable water by condensing purified water from contaminated water sources, comprising: an elongated passive solar water vapor retaining dehumidification container to contain the non-potable water to be separated into potable water and residual sediment, said non-potable water to be put into a vapor phase by heating with solar energy; at least one condenser pipe located within the water vapor retaining dehumidification container for receiving an incoming cold liquid at a lower temperature than the water vapor, such that condensate forms on the outside of the condenser when water vapor is present and lower temperature liquid is in the condenser; and a collection trough under the condenser for gravitationally collecting the condensate which has sweated off the condenser, forming purified water.

15. The condensation system of claim 14, further comprising a pre-treatment pond for pre-cleaning the non-potable water which is received by the humidification container to aid in the process of evaporation into the water vapor phase.

16. The condensation system of claim 14, further comprising a storage tank for storing the purified water collected from the dehumidification process.