Water distillation, desalination and purification (Patent Pending)

Produce purified water at a radically lower energy cost

Powered by the heat in the air around us.

By XDOBS.COM LLC  800-658-8745 sales@xdobs.com

Technology,   Background,,  Physics,  FAQ,  Blog,   Links     A2WH     EEDRT

Water Purification / distillation which produces surplus power. 

Our Distillation process uses a combination of various physics processes in novel ways to dramatically reduce the amount of energy required to purify water using distillation based techniques.     In many climates the process actually processes more energy than consumed which makes it the first water purification process effective when operating in infrastructure challenged areas where the cost of electricity or membranes have previously made providing clean water cost prohibitive.  

Our process borrows thermal energy from the input air combined using advanced evaporation techniques.   The borrowed energy is then captured during the condensing process and used to drive thermal differential motors which make the process work.   It is effectively an indirect solar powered system since solar energy is what heats the air in the first place.

The XDOBS process utilizes a dramatically expanded evaporation area combined with a partial vacuum to evaporate water while the heat in the air  powers the evaporation and results in the air leaving the evaporation chamber being super saturated with over 100% relative humidity.   As he air moves into the condenser it is put under pressure which raises the effective dew point and allows  the moisture we picked up in the evaporation chamber to condense at temperatures substantially above ambient.   This is critical because it allows this condenser capture a large fraction of the humidity even though it is warmer than ambient and warmer than the ambient dew point which allows it to capture more of the latent heat energy.       As the humidity condenses the latent energy supplied by the input air is recovered in the form of heat.   We use this heat to provide the thermal difference in the heat between the warm condenser and the cold input water.  It is this heat difference that is used to power our thermal differential motor which in turn drives air pump to make the process run.       The warm condenser will not capture all the humidity so it is followed by a cold condenser which captures more.         The amount of temperature differential  is Dependant on the amount of vacuum and the amount of pressure.  Higher vacuum and higher pressure basically means lower air flow so there is a trade off between these factors  that yields the best total efficiency and the sweet spot changes based on local air and water temperatures and whether the input air was pre-heated.   Regardless of the vacuum and pressure the system would not produce sufficient energy to self sustain without the very large effective evaporation area which allows us to harvest and re-use the energy already present in ambient air.

Contact sales@xdobs.com or call 800-658-8745 for additional information.

system-overview-diagram

Evaporationchamber detail


Micro bubble diffuser

Background

Millions of people around the world are without safe drinking water and increasing population demands on existing safe drinking water supplies are increasing tension throughout the world to the point where prominent U.N spokespeople are warning about the risks of future wars over access to potable water.   There is a wide range of technology for treating sea and contaminated water to make it safe for human consumption but those available on the market are either too expensive,  require too much power or expensive parts while many of the available technologies simply can not handle water available in the region.   Water is rather expensive to transport due to its weight and the volume used.  Transportation by truck is expensive in fuel, capital and man costs while transportation by pipeline is expensive in capital, energy and land right away.   A process that can produce large amounts of purified water without extensive energy costs,  which can produce safe water from almost any contaminated fresh or salt water source, which can be easily scaled to be installed close to the point of consumption and which can operate for years without expensive membrane replacements is necessary to solve the problem.  This invention provides this solution.

Water will evaporate in most temperatures higher than 32F however as long as water is below the boiling point however the rate of evaporation is limited to the surface tension area of the water and the current vapor pressure which is determined by the airs current humidity and temperature.   Solar stills have used this approach for hundreds of years where they allowed the water to evaporate and then devised a mechanism to capture the resulting humidity once it condensed.  The problem is that the rate of evaporation is generally fairly slow in the temperature ranges for 50F through 90F and as a result the amount of water produced is small per the area of equipment.   Several approaches have been used to improve the rate of evaporation with the most common being increasing heat as the content of the water goes up the evaporation rate goes up but until it reaches the boiling point it is still limited to surface evaporation.   Another approach is to increase the surface area with pads or wicks which increases the evaporation at a lower temperature but are difficult to scale and have terrible problems with mineral build up, fouling and bacterial growth.    The last approach is to build a shallow pond with a dark bottom and allow solar energy to increase the heat while spreading the water out over a larger surface area increases effective surface area this is one of the more scalable historical approaches but if you want to capture the water vapor coming off the pond and condense it to liquid water the entire surface area has to be covered with a water proof layer that allows space for evaporation but captures any humidity stream such that it can be routed through a condenser which is expensive.  The energy cost of heating water to the boiling point makes this process very expensive and pads simply don’t scale well or maintain well so the question becomes how to increase evaporation at a lower energy cost without the scaling and fouling problem of the pads.    Our solution is two fold the first is we use a partial vacuum which reduces and vapor pressure and allows more water to evaporate at a given temperature.    Then we use this partial vacuum for a second purpose of drawing air through a submerged diffuser which creates millions of micro bubbles increasing the surface area of the water by the sum of the surface area of all the bubbles.    In this way we are able to achieve an effective surface area that is as if we had spread the water out to cover thousands of times more surface hence we get the benefit of huge pond without the drawback.   As long as the air temperature is warmer than the water temperature the heat from the air is transferred into the water and further increases the effective evaporation rate.

One of the long term difficulties in large scale desalination plants and distillation systems is that the energy cost of operating the systems is so high that it is difficult to pay the energy overhead and still produce water in a cost effective fashion.  In fact most heat based desalination systems rate input energy as the leading cost per gallon purified.     It requires 2.37KW worth of heat to evaporate a gallon of water using heat only techniques and while part of this can be re-used to pre-warm source water the majority of it is lost in the form of Latent heat Energy which is ultimately dumped back into the waste stream or discarded.   This means these plants must be built near major power facilities where they can buy large amounts of power at discount rates to be cost effective.

 Heat based distillation systems have historically had a problems with mineral buildup on the heated elements which significantly degrades performance and forces the units to be shut down for maintenance.   This is typically caused by a spray of source water which may contain significant salt and minerals hitting the heated surface and while the water evaporates a residue is left behind on the heated surface.  Eventually this residue tends to build up and prevent heat transfer which decreases efficiency and can burn out the heat exchangers.

Modern desalination plants commonly use membranes which retain Desalination using membranes has made this process less energy intensive but energy is still one of the leading costs in the desalination process.    In addition the membrane style plants tend to produce water with higher salt and mineral content which is generally undesirable and they are more prone to failure in the event of contamination by petroleum products.  The plastic materials used in these plants by nature are fragile and must be replaced on regular basis and the cost of plastic continues to increase with the cost of energy so the two major cost items in this type of plant continue to escalate.  The final and possibly most severe issue is that these membrane based plants have a high risk of clogging especially when water mineral or solids contents change and membrane replacement is expensive.

Vacuum based distillation systems which utilize a partial vacuum in conjunction with heat have been available for over 20 years however they where still energy intensive and while more efficient than the heat based systems and more reliable than membrane based systems they tended to be more energy expensive wise than the modern membrane systems.

Many segments of industry produce large amounts of contaminated water.  The oil industry in particular generates “produced water” during both the drilling and production process which is contaminated with petroleum by products and metals and minerals.   In some areas disposal of this waste water has been by dilution into sea water and in others it has been stored in specially lined surface ponds and allowed to evaporate.  The problem with existing approaches is that these surface ponds have a high incidence of leakage into nearby fresh surface water causing widespread contamination.   The petroleum by products in the waste water can film the surface of the water and dramatically reduce evaporation rates which cause the high risk large volumes of surface water to take too long to evaporate.   In the oil industry the specialized surface evaporation ponds are specially lined so that once they are dry the are covered with another liner and the contaminates effectively sealed away from the environment. If they leak, flooded or overflow the concentrated waste solution tends to run off and contaminate local surface and ground water.    In Montana alone billions of gallons of fresh water have been contaminated in this fashion.     In the North Sea heave metal content is exceeding safe limits so new options are required.    There is a need to rapidly extract the contaminants from the produced water in a way that safe purified water can be released to the environment while the contaminants can be concentrated for safe disposal.     Membrane based treatments are beginning to appear for this purpose but many of the contaminants have the unfortunate effect of clogging and or eating the membranes which can make it cost prohibitive for treating adequate volumes.    This invention is particularly good at evaporation of waste water that may resist evaporation due to surface skimming due to the ability of the micro bubbles to provide continuous agitation and it is particularly effective with waste water that would clog or eat membrane due to it’s natural resistance to clogging and the ability to build the core components out of a chemical resistant plastic.


   

Overview of the Technology & Process


Our process effectively creates a very large surface area for evaporation in a very small physical area.  This large evaporation area is made even more effective by a partial vacuum which multiplies the evaporation rate.   Heat in the input air drives the process and we recapture that heat when we condense humidity back into a liquid.  The captured  heat is used to provide power for a thermal differential motor (Stirling)  which in turn drives air pump which drives the entire process.

The Basic process


We use a proprietary mechanism that allows us to increase the effective surface area of the water in our evaporation chamber by several hundreds times and the input air supplies a majority of the heat energy to drive the evaporation.    This is combined with a partial vacuum which allows even more water to evaporate.   As the water evaporates heat is transferred from the input air so rather than investing the full 2.4KWh worth of energy it would require using only heat we are able to invest only the energy needed to move the air and create the vacuum.  

The heat from the input air is insensible after evaporation but we are able to recover it in our condenser.    The condenser is operating at a positive pressure above ambient and the air humidity stream fed in is at substantially over 100% RH (relative humidity) so the increased pressure allows it to condense even when the condenser is operating above ambient temperature.     Some of the humidity may not condense due to the elevated condenser temperature so a second colder condenser is also operating at a positive pressure so the air when discarded is actually at a lower RH than the input air.   This approach allows us to recapture the energy we borrowed from the air to provide the heat source for our Heat differential motors.   The cold side of the Thermal differential motor is kept at the same temperature as the source water which is normally below the air temperature.      The thermal differential motor provides the mechanical power to drive the air pump which creates the partial vacuum and draws the air through our special evaporative surface multiplier and ultimately creates the positive pressure in the condensers.     

It should be obvious that the warmer the input air the better the process works and it is fairly easy to add heat to the input air using solar collectors,  black painted pipes in the sun,   ground loops, etc.  In most warm climates the system will run without pre-heating the air but it will produce more water and more surplus electricity when it is fed the extra heat.     What is less obvious is that the ability to run in a energy positive fashion in a given climate  is predominantly determined by the efficiency of the air pump and the efficiency of the thermal differential motor.     There are Stirling motors that will run on as little as 7F thermal difference but they are generally not terribly efficient and while our thermal difference will be many times higher than 7F we still have to be concerned about this efficiency..

The system can not spin up by it's self because the warm side collector has no heat until it starts condensing water so an electric motor is used to spin the system up until the warm side collector builds up enough warmth to drive the thermal differential motors after which this motor becomes a generator to produce the power needed to replace that which was used during startup.   Depending on scale this motor can also export power for other uses especially when supplied  with input air heated above ambient.

There are all kinds of nuances such as how do you avoid freezing the source water as a result of the partial vacuum?,  How to void crusting and buildup in the evaporation mechanism?,  How to ensure proper discharge of the waste water to avoid over concentration?  How to ensure the cold side heat sink stays cold?   and many others but these are all just engineering details which we can not share without a NDA.
 


Process physics for scientists and engineers



There are 4 critical aspects of our process.  They come together to provide the motive power needed for the system.

  1. It requires 600 calories per gram of water to evaporate or change phase from liquid to gas.    When the gas condenses 600 calories are released in the form of heat energy.     The original energy input for evaporation can come from the air, a stove, flame; etc it really does’t matter but when the vapor condenses to liquid it will release 600 calories worth of heat energy  regardless of where the original heat came from. Water will evaporate at temperatures below boiling but the evaporation rate is relatively low due to being limited by surface area.   The rate of evaporation can be increased by increasing the surface area of the water.  Surface area increases can be accomplished  with pads, bubbles or sprays.  Anything that increases the amount of water in contact with air increases the evaporation rate.   Any evaporation driven in this fashion converts part of the heat in the air into latent energy so 600 calories per gram for the phase change are donated by the air.
  2. The evaporation rate of water can be increased by decreasing pressure or creating a partial vacuum.   It is possible to boil water at room temperature when sufficient vacuum is applied.    When combined with mechanisms to increase surface area the vacuum acts as an evaporative multiplier.   In effect it allows massive amounts of evaporation at temperatures below ambient air or water temperatures.
  3. Dew point can be adjusted to higher temperatures by increasing the humidity content of the air or the pressure.    Or can be lowered by decreasing temperature or humidity.     If you increase humidity and / or pressure enough the dew point will be above 212F.       The  dew point can be adjusted to a specific point by varying the pressure and humidity content.     If the air + humidity stream is under pressure inside a condenser coil then the condenser can be much warmer than ambient even over 212F and still collect condensate.

    Latent heat energy recovered from air during the humidity to liquid phase change (condensation) is retrained in the condenser and can be used to for other purposes.
  4. Whenever a thermal differential exists between a hot body such as a warm condenser coil and a cold body such as a cold heat exchanger it is possible to operate a thermal differential or Stirling motor based on this thermal differential.    The motors deliver more usable power with higher sustained temperature differentials and in the process of operating they will transfer heat energy from the hot exchanger to the cold exchanger.  
 


Process Physics for for non scientists

If you inject heat into water say by boiling it on the stove it will take 2.4KWh worth of energy to boil one full gallon.    It only took about 90% of that energy to heat the water from it's frozen state up to 212F.  The rest of the energy 88% of the 2.4KWh or 2.1KWh is called Latent Heat.     What is less obvious is that if you run all the air that absorbed the water vapor through a cold pipe the water would condense out of the air and you would get all the latent energy back and the temperature of the pipe increases by roughly 88% of the 2.4KWh originally invested in the evaporation.      The energy is actually there but it is being used to hole the water molecules apart and keep the humidity in a gaseous state so we can not feel it.

The same principle is in action when the water evaporated during the day settles out as dew on cool evenings and releases it's latent heat.  This is the reason that nighttime temperatures seldom drop below the dew point especially in humid climates because if the temperature does drop more then more dew condenses and releases more latent heat.

The other way water evaporates is surface evaporation which is driven by a  combination of the water temperature,  air temperature and relative humidity.   If you add heat it will increase the rate of evaporation but it remains a surface phenomenon rather boiling from the bottom like it did on the stove.   As a surface phenomenon the rate of evaporation is limited by the surface area of water exposed to the air.     Ultimately even water at 33F with air at 33F will evaporate using this phenomenon but if you increase the surface area say to the size of the Pacific Ocean it still equates to a substantial amount of water evaporated even at low rates.    

At some point the air picks up enough humidity that if any more evaporates it will will just condenses back out and at this point of stasis the air is at  100% RH (Relative Humidity) or fully saturated.      When fully saturated the air simply can not hold any more water without it condensing ore precipitating out.   The condensing of air when over 100% RH is not an instant phenomenon so it is possible for air to be over 100% RH as can be found in south Carolina  on some summer days.  Whenever the air is over 100% RH it is fully saturated.     There are ways to increase the amount of humidity water can hold one of which is increasing the temperature. 

NOTE:  The XDOBS process depends on the air exiting the evaporation chamber being super saturated.  It is actually over 150% RH.  before it leaves the evaporation chamber and when it is put under pressure in the condenser it is over 200% RH. 

If you look at the water vapor evaporating  off the surface of the red sea and the water vapor coming out of a boiling pot they are exactly the same with the only difference being that the sun warmed the red sea which evaporated the water at a much lower rate.  Either way it required 600 calories per gram.    If  I run the vapor through a condenser it will http://english.people.com.cn/other/book/guestbook.php?book_id=272025&title=Device%20offers%20end%20to%20fresh%20water%20shortage&link=/200606/08/eng20060608_272025.htmlhttp://english.people.com.cn/other/book/guestbook.php?book_id=272025&title=Device%20offers%20end%20to%20fresh%20water%20shortage&link=/200606/08/eng20060608_272025.htmlhttp://english.people.com.cn/other/book/guestbook.php?book_id=272025&title=Device%20offers%20end%20to%20fresh%20water%20shortage&link=/200606/08/eng20060608_272025.htmlhttp://english.people.com.cn/other/book/guestbook.php?book_id=272025&title=Device%20offers%20end%20to%20fresh%20water%20shortage&link=/200606/08/eng20060608_272025.html release the 600 calories per gram as latent energy which is absorbed and retained by the condenser.      This gain is represented as heat and if the condenser is not continually cooled it would eventually become warm enough that the condensing process stops all together.

Standard heat based distillation units also have to invest the 2.37KWh per gallon evaporated.    They generally invest the heat energy in the form of burning gas, electricity or solar heat and then the keep their condenser cool either by dumping it's heat back into the ocean or the air using a radiator.

There a number of ways to increase the heat of condensing.      The easiest is to increase the humidity content of the air.   Water will condense all the way up to the boiling point 212F if the humidity content is high enough.    It will condense at higher temperatures when under pressure say inside a pressure cooker.       Humidity contained in air that would not condense at the ambient temperature can be forced to condense by increasing the pressure.     In effect it is possible to  the dew point up and down by modifying either or both temperature and RH.

One way to increase water evaporation is to increase the surface area it is exposed to.    A common way to do this is to use the water to soak a pad and the blow air through the pad which is the process used by swamp coolers.   What is actually happening during this process is that as the water evaporates as the air blows through.   The evaporation process still needs the 2.4KWh worth of heat per gallon but in this instance it extracts from the heat needed from the air so the air coming out the other side is cooler.    The air was originally heated by the sun so you can say the sun is indirectly providing the energy to evaporate the water.      One of the reasons swamp coolers are cheaper to run than refrigeration based air conditioners is because the warmth in the air is doing most of the work and the fan is just enabling the process.    The big issue with swamp coolers is that their pads build up a crust from minerals in the water and have to be cleaned or replaced.     If we had a way of running all the air coming out of the moist pad through a cold condenser pipe we would still end up recovering the same 88% of the 2.4KWh of heat in the condenser.  
 
NOTE:  The XDOBS process  does not use a pad and the mechanism we do use is immune to clogging, crusting and bacteria growth common with pads.

Another way of increasing evaporation of water is to subject it to a lower pressure.   If you lower the pressure far enough water will actually boil at 32F.

NOTE:  the XDOBS process does not attempt high vacuum but we use a sufficient amount of vacuum to dramatically increase evaporation.   In this instance the vacuum is applied to our large surface area which multiplies the effectiveness of the large evaporation surface even with relatively low vacuum settings.

Thermal Differential motors have been around since the 1600's but the most popular variant is the Stirling motor patented in the early 1800's.   These motors generally operate sealed with a fixed amount of gas.    Heat is applied to one end and cold to the other and the motor will do work normally turning a shaft as long as there is a sufficient temperature difference between the cold and hot sides.   Some Modern Stirling engines run on as little as 7F temperature differences although most are designed for much higher thermal differences.    Stirling motors are used a lot of different places from co-generation in houses to space power for long term probes and submarines.  

NOTE:  The XDOBS process provides temperature differentials many times greater than the minimum of  7F but not anywhere close to the 2000F where the free piston engines operate most efficiently.


 




FAQ - Questions and Answers


Explain what you mean "process producing a “small amount of surplus power”

The amount of surplus power varies greatly depending on local conditions.    The highest amounts of surplus power are produced with extremely warm dry desert air and the lowest amounts in relatively cool very humid air.   In ideal conditions and a fully optimized system we expect to produce in the range of 150 watts per gallon distilled.  In most situations it will be in the range of 1 to 15 watts per gallon excess.  

 The second factor for efficiency is the temperature difference between the local air and the dew point and the low air and the source water.     An ideal combination will maximize power production while non ideal combinations may require addition of external power or heat to continue operations.

Of the mechanics the efficiency of our thermal differential motor is the key factor in determining the amount of excess electrical energy produced.    We are using a relatively low thermal differential as compared many Stirling engines and most low differential Stirling motors operate in the range of 4% to 6% efficiency while the world record Stirling engines operate as high as 29% Heat to Electrical conversion.   To break even our Stirling motor must produce at least 8% efficiency when operating with an input of 85F air at 30% humidity and source water temperatures of 70F.   When operating with those inputs anything over 8% will efficiency will be seen as surplus generated power.

It is important to remember that some power is consumed during the startup cycle so any power produced can not be considered surplus until the power used during startup has been replaced.

On what scale has it been tried / implemented so far?

 The technology has been unit tested at the component level.  It has not been used to produce significant amounts of water due to the capital required to build the next stage units.  We expect the outputs of additional tests over the next few months.

 

How much external energy input does the process need?

In many circumstances the process will actually produce a net surplus of power and will operate indefinitely without any external energy source other than the heat already present in the local air.      

In the depths of space everything tends to be at close to absolute 0 which is about -237F.    The air on earth is heated by the sun until generally ranges from -30F up through 120F.     The difference is energy the air has absorbed from the sun so you could say that we are using an external energy source which is the heat in the air but since we are using energy already gathered and collected by the air it is more cost effective than specifically heating  the water or the air.    

Every evaporative process uses the same amount of total energy for evaporation and ours is no different but we are using a portion of the trillions of watts worth of energy absorbed by the air every day.      With this said additional heat can be added to the process which will improve it's efficiency and increase the amount of surplus power generated and relatively small amounts of heat can dramatically increase productivity.
 

Is this brand new Science

Well we do not expect to win any Nobel prices for physics.    Seriously we have not invented any new startling science but rather combined the work done by the great physicists and engineers from the past and every part of the process has very similar analogs in nature even today.    We have combined these processes in a novel way that we expect to provide a cost effective solution to a growing problem.    

Please contrast your process with existing technology and products

You can not find our total process in any one piece of equipment otherwise it would not have been patentable.    However portions of our process are used in many different technologies.    

Can this process and technology really substantially decrease the amount of energy used in desalination and thus get round the problem of high energy use that desalination normally requires, especially thermal techniques.     

In many climates the system will operate indefinitely without external electricity or fuel.        The system will normally be able to operate indefinitely without any electricity or fuel when the air is more than 30F warmer than the input water temperature or where the dew point is more than 15F below ambient.

The efficiency of the system can be increased by adding additional heat to the input air or water.   The increased efficiency effectively lowers allows less hardware to produce more water.   

Are the pumps driven by electricity?

The pumps are driven by Stirling motor (heat differential motors)  which are powered by the temperature difference between the warm heat and cold heat exchangers.    The heat differential is converted into mechanical energy in the form of a spinning shaft which in turn drives the air,  vacuum and circulation pumps which drives the entire process.

Electricity is only used during startup.    When the process is starting there is no heat differential so an electric motor is used until sufficient heat has built up in the warm heat exchanger.    After startup the electric motor transitions into generator mode to power the electronics and recharge the batteries for next startup.

In the provisional patent  we also show the use of a liquid piston pump which we also have a patent pending on.  This pump allows us to directly convert high temperature low pressure air flow into the air flow we need to drive this process.  The advantage of this pump is that it is substantially more efficient than most other approaches while the disadvantage is that it is more complex to drive from electricity during the startup phase.  The liquid piston pump is most often used in situations where non trivial amounts of heat energy are being supplied from external sources such as solar thermal collectors using our proprietary Ellsworth process.


Would this work like an air-source heat pump?     I did not quite understand from your explanation how you harvest the energy from the air.


It is not like an air source heat pump.

Short latent energy harvest explanation

When water changes phase from liquid to gas 600 calories per gram are invested.  Our evaporation strategy obtains the 600 calories per gram from the air.       When the same water changes phase from gas to liquid 600 calories per gram are liberated in the form of heat.         Increased pressure and humidity inside a sealed condenser force condensation to occur substantially above ambient temperatures.      The condenser absorbs 600 calories per gram in form of released latent heat which is transferred to the warm heat exchanger.    The warm exchanger eventually accumulates sufficient heat to be substantially above ambient.       The temperature difference between the warm and cold heat exchanger power Stirling motors which provide rotational energy to drive the air, vacuum and circulation pumps.   The warm heat exchanger is kept warm by the continued condensing process while the cold heat exchanger is kept cold by circulating source water or secondary heat exchanger.
 

A longer Explanation

This one is difficult to answer quickly but here is a short explanation:   When water changes phase from liquid to gas 600 calories per gram are invested.   When the same water changes phase from gas to liquid 600 calories per gram  are released in the form of heat.  If the water is condensed inside a condensing coil then a majority of the heat is retained by that coil.     If you use

Our process increases evaporation rates using a Micro bubble diffuser which is effectively a pipe network with millions of very small holes.  Air is drawn through these holes and turns into billions of very small bubbles.  The total surface area of each bubble becomes our evaporative surface area and gives us a very effective evaporation system.   In addition we use partial vacuum  to draw the air through the system which multiples the effective evaporation rate from the micro bubble diffuser. 

For each gram of water we evaporate 600 calories are transferred from the input air into latent energy represented in the water vapor.   The humidity laden air stream from the exiting evaporation chamber may be over 800% ambient RH.       

After the evaporation stage the humidity laden air is transferred to a condenser which is under pressure.    The combination of the higher pressure and high humidity content allows the humidity to condense back to liquid water at temperatures substantially above ambient.     During the gas to liquid phase change 600 calories per gram of latent energy are released in the form of heat which is absorbed by the condenser coil and transferred to our warm side heat exchanger in which it is submerged. 

 The ultimate result is that the first condenser can be 20 to 150F warmer than the cold side heat exchanger which is kept at the same temperature as the source water.      

The heat differential between the cold heat exchanger and the warm heat exchanger provides the energy to power a Stirling motor which drives the main air, vacuum and circulation pumps. 
 

What (if any) external energy sources does your device use? 


The best way to add energy to our system is by pre-heating the input air which maximizes evaporation rates and increases the thermal differential that is powering the Stirling motors.     This heat can easily be added ranging from black pipes up through tracking collectors.   Heat could also be added via a gas burner and standard hot air exchanger or ground loops.       Adding 240 watts of heat energy per gallon distilled can triple the output of a given set of equipment.  240 Watts is equivalent to 0.6 sq foot of solar thermal collector per gallon per day.

In areas with very cold winters like Park City, Utah the process can enabled for year round operation by changing the configuration to use the cold air to chill our cold side heat exchanger and a ground loop to pre-warm the input air to 68F.   This approach provides higher thermal differentials and allows the condensers to operate even more efficiently.   

Careful tuning this approach can allow the process to operate energy self sufficient down to about 0F although anything under 32F requires special precautions to avoid freeze up.    This is a form of adding external energy which is being tapped from the ground.
 

"Surely the process can’t produce more power than it consumes?"

It is more accurate to say the process is powered indirectly by solar heat.   The sun heats the air of the earth.  We use heat in the air to aid in the evaporation process.  The heat contributed by the air gets locked up as latent energy.  We harvest the latent energy during the condensing process and use the harvested heat to drive the entire process. 

Warmer air works better because it contributes more energy and  the process will not operate self sufficient in cold climates.    The thermal range will expand to include colder areas as we improve our mechanical efficiency.    The Rev 1 version could work in colder areas but would require pre-heating the input air.


 Do you have a website I can look at?

See:  http://CorrectEnergySolutions.com/water-distillation

There is an original overview document for a portable version published at http://www.xdobs.com/energy/purifier/portable-distiller/introduction.html  but the technology description in this document was deliberately vague.

Many of the same underlying physics are used by our Air to water and the solar thermal cooling system which have public sites  http://a2wh.com  and http://eedrt.com



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