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Water Management System Description




Abstract



Part 1: Overview

About AquaDyn Technologies, Inc.


AquaDyn Technologies, Inc. is a service company offering an alternative to traditional industrial water treatment.  AquaDyn provides a water management service, which utilizes a combination of water management technologies that will reduce operating expenses by as much as 34% (up to $40/ton/yr). AquaDyn is a growing company, providing water management services to cooling tower/evaporative condenser owner-operators and to fire-tube boiler owner-operators. Focusing on providing water treatment solutions, AquaDyn is proving itself to be a service and technology leader in the industry.

FIG 1: Stand-alone water management unit

State of the Art Water Treatment Solution


Industrial cooling and boiler systems are a key element to the profitability and production reliability of industries, nationwide.  The treatment of water used in these systems is a key element that can increase or decrease operating expenses such as electricity, water and sewage, equipment maintenance and repair.  Furthermore, water treatment methods can directly affect productivity quotas if plants have to be down for equipment repairs. Traditionally, industrial fire-tube boiler and cooling systems use chemicals to treat their water.  AquaDyn has found that chemically treated water can be 34% more expensive and is less effective than its risk-free alternative for treating water.

FIG 2:  Chemically treated cooling tower bath and below it the same cooling tower bath after four weeks with AquaDyn


Using physics not chemistry the AquaDyn Technologies Water Treatment System provides as much as 34% Savings in Operating Expenses with Electrical Savings, Chemical Elimination, Scale Elimination and Prevention, Maintenance Reduction.

  • Clear Water
  • Risk Free Water Treatment
  • Clean Towers
  • Pollution-Free Water
  • Committed Engineering Sales Consultants
  • Qualified Engineering Service Technicians
  • Customer Satisfaction

The AquaDyn Water Service Module


The AquaDyn Water Management Service unit is owned, installed, and maintained by AquaDyn.  The AquaDyn unit is located on a portable stand or affixed to the tower or towers being serviced or may also be fixed to a structure in the vicinity of the tower or towers being serviced.  The boiler water management unit is attached to the boiler and located nearby.  Both systems are electronically and magnetically powered using an electrical source provided at the tower.

FIG 3:  Another stand-alone water management system

The AquaDyn Water Servicing Module operates continuously and provides service to the cooling tower, evaporative condenser, and/or chilled water system(s).

AquaDyn maintains the equipment and upgrades the equipment as required for the efficiency of operations and by the requirements of maintaining the waters or liquids of the particular boiler, cooling tower, evaporative condenser, or chilled water system.

Summary of Benefits


The AquaDyn Water Management System controls a number of persistent problems associated with traditional water management techniques:

  • Algae
  • Bacteria
  • Water pH
  • Pitting
  • Corrosion
  • Scale
  • Slime from microbiological growth
  • Accumulation of unwanted solids
  • Microbiological Induced corrosion

The system removes existing scale and biological film from older systems.  In addition, the system controls cooling tower water/evaporative condenser water and chilled water to the following limits

Bacteria growth................................................................................ < 106 colonies/ltr

Fungal growth................................................................................... < slight or none

Algae................................................................................................. < slight or none

Pitting................................................................................................ < 2 mils/year

Corrosion.......................................................................................... < 2 mils/year

Scale................................................................................................. = none

pH...................................................................................................... ~ make up water

Hardness (TDS)............................................................................... > make up water

Water dynamics...............................................................................    soft

Blowdown ........................................................................................    zero


What Happens when HVAC Systems Are not Operating As Designed
The major expense in almost all chilled water/ammonia systems and their attendant cooling towers is the electrical costs required to operate the compressor motors in the chilled water or the ammonia sections.   Preventive maintenance or shut down repair is the current option for addressing the scale and film problems that exist in all of the condensers.   As the D T of the condenser water decreases, the head pressure of the refrigerant increases, which requires a greater brake horsepower to drive the compressors. The increased demand on the motor drives the electrical cost up and drives the life of the equipment down.

Delta (D) T is the difference between the temperature of the supply water from the cooling tower to the condenser (heat exchanger) and the exit temperature.  For instance, 78oF in and 88oF out is a D T of 10oF.


As many users can attest, the improper management of cooling tower water can drive operating costs sharply higher and reduce the useful life of the associated condensers/heat exchangers.  Traditionally, chemicals are used to treat the water in cooling towers.  Often the chemicals are not properly balanced because the makeup water changes or the foreign contaminants that are sucked into the towers changes the chemical treatment, i.e. pH swings etc…

The total dissolved solids generally reach critical levels and rapid scaling occurs on all surfaces where the tower water comes in contact with the tower walls-bath-fan-cowling, piping, and tube bundles.  Scaling reduces the heat transfer efficiency while it acts as an insulator and the system cannot operate at its optimum level.  The areas of most concern in each system are those locations where rapid temperature changes and/or flow restrictions occur, such as heat exchangers or condensers.  The dilution or  “bleeding” wastes water and the chemicals that have been put in the water to control algae, fungus, bacteria, viruses, scale, etc.  Electrical costs rise, the equipment life is reduced, the possibility of health hazards increases, and the chemically laden bleed, which is discharged, destroys the operational efficiency of every waste water facility into which it flows.

1 BTU  (British Thermal Unit) will raise 1 pound of water 10 Fahrenheit

 

Therefore,

 

2.4 gpm X 10 0F X 8.333333 (wt of water) X 60 min  = 12,000 BTU/Hr

 

12,000 BTU/Hr = one ton of refrigeration


The AquaDyn Water Management System, coupled with the AquaDyn Water Management Service, is a process that manages cooling tower waters, generally, without the use of chemicals.  Certain chemicals are utilized in the management of boiler water (and under certain conditions in cooling towers), in addition to the AquaDyn water management system.

In fact, the AquaDyn system meets the needs in the evaporative operations of chilled water systems, ammonia systems and cooling towers not currently being met by the chemical industry, which significantly impact the efficiency of the total, on-going operation. The bottom line: AquaDyn is not just a replacement for traditional chemical management, but a superior water management system.

FIG 4: Typical chilled water system operating at design = 100
D T in each section

The diagram, (Fig.4), is illustration of a typical chiller system operating at design.  In order for the system to operate at design with a D T of 10, the system must be properly maintained.  Cooling towers play a key role in the function of the system.

A poorly maintained tower can reduce chiller efficiency so that annual electric costs can increase by as much as $46/ton ($23,000 increase for a 500 ton system).  AquaDyn’s service brings a cooling system back to its optimum design.  Overall, a system operating at design will lengthen the equipment life, decrease operating costs, prevent serious health problems, reduce pollution, and help ensure peak performance of a system.

Chilled Water Systems
When the tubes inside the Chilled Water Condenser (heat exchanger) are fouled (scale of bio-film) it is the equivalent of insulated heat exchange tubing.  The heat in the refrigerant gas on the shell side doesn’t transfer through the tube wall into the cooler water (condenser water) from the cooling tower that is inside the tubes.  Therefore, the refrigerant is at a higher temperature than design when the compression cycle begins.

When the warmer gas gets to the compressor, the compressor requires greater brake horsepower to compress the gas.  This means more electricity is needed to make the motor turn.  Eventually the motor reaches a point when the heaters in the motor starter trip the system, or in the case of the more recently designed chilled water systems, the systems limit (reduce) the refrigerant flow to the compressor.  This limitation, unfortunately, reduces the performance of the system (reduced BTU removal) but it does prevent the motor from burning out.

The result is the compression of less refrigerant.  The reduced volume of refrigerant means fewer BTUs can be absorbed by the refrigerant during the evaporation cycle, which in turn delivers fewer BTUs to the condenser for transfer to the condenser water (cooling tower water), which ultimately results in lower total BTU rejection by the system.

FIG 5: Clean bell and condenser tubes after a three-month demonstration

Ammonia Refrigeration Systems

When the condenser in an Ammonia system becomes fouled, the fouling reduces the heat exchange efficiencies in the condenser.  The reduced heat exchange rates cause the electrical cost of operation to increase and the output of the Ammonia system decreases.

Evapco estimates that fouling of 1/32 of an inch of scale will reduce the operating performance by 30% and 1/16th of an inch will reduce performance by 55%.

The basic formula is as follows:

 

Refrigerant                                                                             ammonia

Suction temperature                                                            00F

 

Condensing temperature                                                     design                   actual

                        850F           to       950F

Discharge pressure                                                              design                  actual

(As a result of condensing temperature increase,            151.7psi     to       181.1psi

the discharge pressure increases)                                    

 

Increase in pressure                                     (Pa)     =   29.4psi

Pure refrigerant condensing pressure                    (Pb)     = 169.2psi

System capacity                                                        (C)       = 1000 Tons

Energy consumption factor                         (H)       = .80

Hours of run time                                                       (T)       =  6500 Hrs

Electrical rate (including demand)                          (M)      = .05/KWh


The formula for calculating the increase in electrical costs is:

Pa / Pb x C x H x T x M  = Increased electrical operating cost

29.4/169.2 X 1000 X  .80 X 6500 X  .05  =  $45,177.28/yr


The attached drawing provides the corresponding increases in brake horsepower (BHP) required, when the condensing temperature rises, as well as the reduction in system output.

Fig 6:  Typical two stage ammonia system

Refrigeration engineers and service personnel usually describe the status of an ammonia system as” it has a discharge pressure of 185 psi, therefore we have a temperature of 96.30F”.  In reality, if the compressor is fully loaded, the discharge pressure does not set the temperature, rather the fouling (or lack thereof) of the condenser determines the exit temperature of the gas/liquid from the condenser and that in turn determines the discharge pressure at the compressor.

If an ammonia system was operating at full load with a condenser exit temperature of 96.30F, and the fouling in the condenser was eliminated during operations causing the exit temperature to drop to 86.40F, then the discharge pressure would drop automatically from 185psi to 155psi.  The corresponding BHP requirements of the compressor would reduce by 7%, absent any other changes.

Once an ammonia system becomes fouled, the system turns on itself and becomes its own worst enemy.  The thermal expansion valve (TXV), responding to increases in the exit pressures of the gas from the evaporator begins to reduce flow and valve C opens which allows hot ammonia to be redirected to the ammonia compressor.  This redirection damages the operational efficiencies by introducing high-pressure gas to the compressor and by reducing the flow of cold ammonia through the inter-cooler.  The reduced flow of cool ammonia gas through the inter-cooler insures that the approach temperature and pressure of the ammonia liquid supplied to the evaporator will continue to rise.  As a result, the BTU collection in the evaporator is reduced and the cost of compression increases.

FIRETUBE BOILERS

The operating efficiency of a boiler is determined by the same factors that determine the efficiency of operation for a chilled water system, an ammonia refrigeration system, and/or an air compression system.  The controlling factor is always “heat transfer efficiency”.  For the sake of this discussion we will collectively ignore the reality of dirty air handlers, low refrigerants, non-compressibles in the ammonia system, and air-fuel mixtures that are not set properly.

Recording the stack temperature of the boiler can usually identify the tube fouling that occurs in a boiler.  The less heat from the boiler fire that passes through the tube wall into the water, then the more heat that escapes out through the last tube pass and into the stack.  Thus, if one records the stack temperature under level operating circumstances, the stack temperature will increase as the operating efficiency of the boiler decreases and visa-versa.

Air Compressors

Extensive studies have been conducted in an attempt to conclude the relationship that exists between the brake horsepower (BHP) required in the compression of air and the barometric pressure.  Additional tests have been conducted that identify the loss and gains in compression efficiency when there is a rise in the temperature/moisture of the standard cubic foot of air, which in the US, is fixed at 600F and 14.7psi » dry weight of .0763 lb. -specific gravity of 1.00

FIG :7Compression cycle of an air compressor
However, very little test data is available that clearly defines the increased BHP required when the discharge temperature of the compressed air is allowed to increase due to fouling and inefficient heat transfer in the after cooler or the air dryer.

As seen in Fig. 7, compression is from point A to B and as soon as the compression pressure exceeds the receiver pressure sufficiently enough to open a discharge valve, the discharge cycle, which is B to C, begins.

The formula that defines Volume “ V”, Pressure  “P”, and Temperature  “T” for any gas is PV = RT (R is the gas constant which is 53.4 for air).  The formula essentially dissolves into P = RT V or P = 53.4 T ⁄ V.  The volume in an air compressor receiver system is constant; R (53.4) is constant, so essentially as the Temperature of the discharged (compressed) air increases, the pressure in the receiver increases.  Therefore, as the discharged air pressure increases in temperature the receiver pressure increases, which means that it is more difficult for the compressor to achieve a compression pressure that exceeds the receiver pressure.  “More difficult” translates into a greater BHP requirement for the compression cycle.  It should be noted that AquaDyn understands that the R for air changes as the contaminants change, i.e. moisture content, etc.

           

How AquaDyn Monitors Success


The AquaDyn water management system will return the boiler, cooling tower, and/or evaporative condenser system to design conditions as specified by the manufacturer of the equipment.  Data is furnished by the manufacturer and serves as a baseline for AquaDyn to monitor and ensure that the overall system is operating as designed:

  • evaporator entering water temperature (EEWT)
  • evaporator leaving water temperature (ELWT)
  • evaporator flow rate
  • condenser entering water temperature (CEWT)
  • condenser leaving water temperature (CLWT)
  • condenser flow rate
  • condenser shell pressure
  • suction pressure
  • shaft horsepower at 100% load
  • electrical consumption at 100% load
  • boiler stack temperature
  • boiler gas/fuel consumption
  • ammonia suction pressure
  • ammonia discharge pressure
  • ammonia compressor run time data
  • additional data peculiar to individual systems as required

 AquaDyn then calculates for the following conditions:

  1. Values for all parameters at 100% load.
  2. Relationship between 100% load conditions and design
  3. Values for all parameters when the shell pressure of the refrigerant increases from design by .5psi, 1.0psi, 1.5psi, and/or 2.0psi as it passes through the condenser.
  4. Values for all parameters when the approach temperature of the refrigerant becomes larger than 1 0F (exit temperature of the condenser water and the exit temperature of the refrigerant)

Water for fire tube boilers must meet the following:

Hardness……………………………………………………<2ppm

Dissolved oxygen…………………………………………..<005ppm

Carbon dioxide (ratio of alkalinity to CO2)………………>3:1

Hydrogen Sulfide…………………………………………...<5ppm

 

However, in the final analysis, the water for Chilled Water systems, Ammonia systems, and Air Compressors must meet the following:

 

  • Bacteria growth< 106 colonies/ltr
  • Fungal growth< slight or none
  • Algae< slight or none
  • Pitting< 2 mils/year
  • Corrosion< 2 mils/year
  • Scale  = none
  • pH~ make up water
  • Hardness (TDS)> make up water
  • Water dynamics=soft
  • Blowdown= Zero

FIG 8 & 9:  Stand alone water management system and the result-clean water in the tower bath

Linked Access Data Delivery (LADD)system

The metering devices installed by AquaDyn should provide the groundwork to establish operational savings (if any) during the demonstration in the following categories:

  1. Electrical savings = to be established through the metering devices installed under 1 through 3 above.
  2. Blowdown water and sewage loss to be established through the metering devices listed in 4 above
  3. Chemical savings = 100%
  4. Maintenance savings = furnished by customer

Operating costs will, in all situations, be reduced to the cost to produce the unit in question: removal of BTU through a chilled water system, the removal of BTU through an ammonia system, the cost to produce cubit feet of compressed air, and the cost to produce steam.

                                                                               

  1. AquaDyn will install metering equipment that will sample the Delta T through the condenser every three minutes and calculate an average hourly operating tonnage. 
  2. AquaDyn will also install a flow meter to determine flow rates.
  3. AquaDyn will utilize the Square-D 3020 enercept meters to determine the KWh for each of the compressor motors involved in the demonstration.
  4. Gas metering devices to determine the fuel cost/unit of steam produced.
  5. AquaDyn will install water meters as required to determine total makeup water flow to the towers and the total being wasted through blowdown.

Part 2: Technical Overview

How the AquaDyn Water Treatment System Works


The AquaDyn Water Treatment System uses specially placed magnetic fields to condition the tower water so that scaling will not occur, even if the total dissolved solids reach levels in excess of four times those allowed by chemically managed programs. 
AquaDyn’s Water Servicing Module is designed to take advantage of the magnetically treated water, which requires far less dilution while maintaining “scale free” characteristics.
AquaDyn’s system generates and releases copper and silver ions into the tower’s flow. The ions kill and control all forms of algae, fungus, bacteria and viruses.  The need for biocide chemicals is eliminated.

 

FIG 10: Typical Biocide appratus and magnetic field generator locations


NOTE: The figure above is the drawing utilized by the Air Force in an article titled Non-Chemical Device Protocol dated 9 Apr 1998 published in the Society of American Military Engineers magazine.  The research project, (MEEP # NR-EC93-63C-BAILMENT # NR93-6), was successfully completed by AquaDyn in1997.  That project led to the revisions in AFI 32-1054 that changed paragraph 4.3.17, which had previously prohibited the use of Non-Chemical water management systems on cooling towers and boilers owned or operated by the Air Force.  The new paragraph permits the use of non-chemical devices that conform to the science embodied in the drawing above.

AquaDyn Water Treatment System Technical Details


The AquaDyn Water Management System has five basic functions:

  1. Controls bacteria and fungus with Bio-cide Generator
  2. Eliminates Corrosion and Pitting
  3. Controls Solids and Scale through Magnetic Field Generators
  4. Continuously Removes Solids and Other Debris
  5. Filters Unwanted Solids, Scale, and Debris
  6. Controls Bacteria and Fungus with Bio-cide Generator

Controls bacteria and fungus with Bio-cide Generator

The Bio-cide generator used in the AquaDyn system continually discharges copper ions to kill fungal growth, as well as generating silver ions to kill bacterial growth. The Center for Disease Control (CDC) and the medical community have both recognized silver nitrate as the basic destroyer or arrestor of bacterial growth for many years, leaving no doubt as to the effectiveness of silver ions to kill bacteria regardless of the source of the microorganisms, including salmonella, pseudomonas, herpes, polio, and Legionnaire's disease.

  FIG 11:  Electrodes shown inside Lexan crosses utilized by AquaDyn

The use of copper and silver ions dates back to the Persians who used the galvanic charge generated by dissimilar metals in low solids water (highly corrosive) to maintain the purity of the army’s drinking water on long campaigns.  More recently this process of controlled ion discharge was developed by NASA and used on the Apollo moon shots. The silver ions will completely destroy all known natural microorganisms, which means: no biological film and no reduction in heat exchange efficiency

At various times of the year, nature produces abnormal amounts of nitrogen. That nitrogen is usually accompanied, especially during heavy rains, by frog eggs, fish spit and various other organic contaminants. The AquaDyn system is supplemented during those times with small doses of concentrated sodium hypochlorite.

The formation of slime as a result of the activity of a large variety of microorganisms is perhaps the most insidious problem encountered by the owner or operator of a cooling tower. There are three potential avenues for these microorganisms to contaminate the cooling tower water:

  • Airborne microbes
  • Introduction of common soils blown into the tower or sucked into the system by the cooling tower fans
  • Makeup water

Regardless of the source of the microorganisms, the problem is that the introduction is continuous (except in very cold conditions) and the chemicals required to eliminate the problem are as varied as the organisms themselves. In fact, many of the organisms can eventually become immune to a particular chemical cure.

The microorganisms flourish in the absence of light, generate their own oxygen and prefer the warm environment of the condenser tube bundle. They actually produce sacrificial outer layers that can take a hit from most chemicals without allowing the host, or generating organism, to be destroyed.

They also thrive in the chilled water side (evaporator to the air handling unit) and are generally the cause of microbial induced corrosion (MIC). The organism secretes a mild form of sulfuric acid. The acid erodes the steel piping, which the organism incorporates into its diet, continuing a vicious circle as the organisms grow and multiply as corrosion increases. This problem is especially prevalent in systems that have heat pumps in lieu of air handling units.   See the AquaDyn BIOFILM WHITEPAPER, for a more extensive treatment of this subject.

FIG 12:  Dirty heat exchanger-covered in bio-film

The magnitude of the bio-film problem is missed by most owners and operators, as the slime is not thought to physically damage the tube or plate sections as scale does. However, the produced slime has a heat transfer characteristic that is the equivalent of a stagnant water layer along the heat exchange surface that can be up to 600 times more resistant to thermal transfer than most of the metals used in the tube section of chilled water or ammonia condensers.

As Betz Laboratories, Inc., Trevose, Pennsylvania, states on page 189 of their section on "Microbiological Control-Cooling Systems,” taken from their Handbook of Industrial Water Conditioning (9th edition):

The simple, passive presence of the biological deposit prevents corrosion inhibitors from reaching and passivating the fouled surface.”

“Microbial reactions can accelerate ongoing corrosion reactions.

Microbial by-products can be directly aggressive to the metal.”

Tests have shown that a 1mm thick accumulation of bio-film on a low carbon steel exchanger wall is the equivalent of a 80mm increase in the tube wall thickness. That equates to a reduction in the thermal exchange characteristics of a carbon steel tube by 26.25%.

Eliminates Corrosion and Pitting

Corrosion is the result of chemical and/or electrochemical reactions between a particular metal and its environment.  Cooling tower water that has a low pH or low solids or a combination of both is very corrosive.

pH is the measure of free hydrogen (H) and hydroxide molecules (OH) in an aqueous solution. In any given unit of water the neutral pH of the solution is generated when there are 7 Hydrogen and 7 Hydroxides, the combination of which equals 14 total. Therefore, a pH of 9 would indicate that there are 14-9 = 5 hydroxide radicals.

Most cooling towers that are managed with chemical bio-cides and algae-cides generate pH problems as a result of the time release principles constructed into the Bio/algae-cides. Most of the chemical bio/algae-cides require hydroxide radicals to facilitate the bio/algae-cide release, thereby increasing the ratio of hydrogen units relative to the hydroxide units remaining.

Relative to corrosion, the AquaDyn system is clearly superior to traditional chemical treatment. AquaDyn eliminates blowdown, which serves to increase the solids until corrosion and pitting are eliminated. The increases in solids that occur with the AquaDyn water management systems increases the calcium content and generates a higher pH under normal operations.

FIG 13:  Calcites, which have been purged from a tower bath and ready for disposal
The AquaDyn water management system generates solids of 1500 ppm in evaporative condensers and 3000 ppm to 4500 ppm in cooling towers.  The extremely high solids content generated by the AquaDyn system completely precludes any corrosion or pitting. In addition, high solids water will transport heat more efficiently than low solids water.

Standard operating procedures for chemically treated cooling tower water is to maintain a solids content in the 450ppm to 1000ppm range. 450ppm is considered to be the lowest solids content possible in chemically managed water to prevent tower and condenser corrosion.

Scale and film removal: The final part of the corrosion formula is the necessity of removing existing scale or film and the prevention of additional scaling or film formation. This removal eliminates most of the electrolysis that always exists to some degree between dissimilar metals and/or organic-metallic solids.

FIG 14:  Calcites that have been purged to a rooftop for removal-too many solids for the internal drains

A deficiency inherent in the chemical management of the water in a cooling tower is that there are no chemicals that will prevent scaling if the water contains high concentrations of Calcites. (Some chemicals can reduce scaling but no

eliminate it.) Calcites are the result of the presence of calcium hydroxides or calcium carbonates in the make-up water. By utilizing chemicals, owners of cooling towers are forced to consume large volumes of water on a daily basis in order to sweep the solids out of the operating system to keep significant scaling in the tube section from occurring.

A rough example of the potential solids growth is as follows:

Assume that a tower is being replenished at the rate of 10 gallons per minute - 8 gallons are evaporated and 2 gallons are for solids control  [blowdown]

Cycle of concentration mathematics

Average solids of makeup water ..................................................   100 ppm

10 gallon of makeup water @ 100ppm ........................................ 1000 ppm [total]

8 of 10 gallons evaporate and leave..............................................   800 ppm behind     

2 gallons of original make up water remain..................................   200 ppm

Total solids remaining..................................................................... 1000 ppm

Total gallons remaining...................................................................       2 gal

Average solids per gallon    (1000gal/2gal)..................................   500 ppm

Cycles of concentration  ................................................................. ..... 5



The constant evaporation out of the system increases the volume of total dissolved solids (TDS) in the water required to service the system, as the solids are left behind when the water evaporates. The TDS increase is continual as makeup water is introduced to the system to compensate for evaporation. In some instances, the TDS increase can be more than 27% daily if there is not a significant amount of blowdown. In the absence of blowdown, the growth in solids becomes exponential in its increase until equilibrium is reached at about 4000ppm in cooling towers and about 1500ppm in evaporative condensers.

         FIG 15: water molecule 

                               

            FIG 16: water and calcite crystal 2 negative charges


Background: Historical problems with corrosion stem from the fact that the water molecule, which is comprised of two gasses, has an electrical configuration shown in Figures 15 and 16.

FIG 17:  Scaled evaporative condenser tube bundles-note scale on cowling

The water molecule attracts positively charged units and repels negatively charged units, such as a calcite. Calcites therefore, are held in suspension by surface tension of a mass of water in the manner shown in figure 16 below:

FIG 18:  lattice created by bi-polar water molecules

By examining FIG 18 closely, it becomes clear that there are primary and secondary bonding ports and potentials at work in water through the electrical charges of the individual molecules and their components. Suspended solids, such as non-water soluble Calcites, are easily trapped in the latticework that results when the secondary bonding develops between the hydrogen and the oxygen in neighboring molecules. This entrapment is generally referred to as surface tension.

The magnetic fields generated by the AquaDyn system beneficially alter both the primary and the secondary bonding and effect a change in the lattice. This results in variations in the surface tensions.

Dealing with the dissolved solids is complicated by the presence of suspended solids such as clays, which have no permanent molecular charge and are in fact isoelectric.  The solids will alternately exhibit either a positive charge or a negative charge depending upon their neighbors. This means that the particles may be momentarily attracted to a negative charge and begin to migrate toward the closest source of that charge, only to change polarity and be repulsed by the negative charge.

FIG 19: Heat absorption increases the distance between water molecules

The issue of dissolved solids in cooling tower water is further complicated by two conditions, which result in calcite’s precipitating out of the water and becoming scale on the surfaces of the pipes in the chilled water condenser:

Undirected water molecules (those which have no magnetic or electromagnetic field) and calcium carbonate and the Calcites all have a net negative charge. The resulting negative repulsion that exists means that the water molecules tend to drive out, or precipitate, the CaCO3 even under normal conditions.

When the water removes heat at the chilled water condenser or comparable heat exchanger, heat transferred to the water weakens the molecules’ secondary electrical bonds, pushing the molecules further apart and stretching the electrical bonds.

When the secondary bonds are stretched, the strength of the lattice weakens, and the water can no longer bind as many solids in suspension. Calcite precipitation and scale on piping surfaces are the results.

Calcite is a short textured material that is not water-soluble and will scale out onto hot surfaces. A Calcite (CaCO3) is an ionic crystal where the (CO3)-2, (a covalent bond), is ionically attached to the Ca+2. This means one or more of the electrons are actually transferred completely from one atom to another, thus converting the neutral atoms into electrically charge ions that either attract or repel and in this case, the Calcite repels other negatively charged particles).  The shape of the calcite is that of a rhombohedral where the metal ions are shielded by 6 oxygen ions. The crystal form of the Aragonite (also a CaCO3) is that of a Hexagon in which the metal ion is shielded by 9 oxygen ions. The Aragonite is a long crystal and is water-soluble. The Aragonite crystal is not ionically bound, as is the calcite crystal.    

FIG: 20                                                                                                FIG: 21


Controls Solids and Scale through Magnetic Field Generators

The AquaDyn system also contains an appropriate number of magnetic field generators. The magnetic field generators provide extraordinary benefits compared to traditional chemical management programs.The use of the magnetic field generators provides some amazing alternatives to the historical chemical management programs.
The first phenomenon that is observed as a result of the magnetic field is that the magnetic field generators cause the calcium carbonates to reduce to an aragonite crystal rather than a calcite crystal.  The aragonite will not produce or contribute to an insulating scale on the condenser/heat exchanger tube walls, because it is a water- soluble material.  The aragonite crystal is bound and not trapped, as is the calcite crystal.

FIG 22: Magnetic field generator with north and south poles clearly in force


FIG 23:  Magnetic field generator with the south poles in force (mono-pole)

The phenomenon created by magnetic field generators is discussed more extensively in the Department of Energy “Federal Technology Alert” publication titled Non-Chemical Technologies for Scale and Hardness Control.  Several test cases and the savings which are attendant to the use of the proper magnetic field generators are included in the publication.
The second phenomenon that is observed as a byproduct of the magnetic field generator is the production of soft, “wetter water.”

Hard water is generally categorized as a liquid that exhibits a higher surface tension as a result of its mineral content. Traditional thinking is that higher tension in and between the lattice of water molecules must be high (hard) to hold the higher solids content in suspension. Water that has a high surface tension is the result of more intense secondary electrical bonds.  The stronger bonds can usually sustain a higher incidence of trapped solids.

However, it is actually the reverse when the water is under the influence of the proper magnetic field. The use of the magnetic field in AquaDyn’s system reduces the surface tension in the water molecules as the secondary electrical bonds respond to the magnetic field rather than the opposite charge exhibited in and on the adjacent molecules. Thus, the water begins to behave as though it were constructed in a linear configuration rather than a triangular configuration.

FIG 24:  Calcites, which have accumulated in a tower bath


The solids continue to build under this change in the water chemistry as a result of the solids change from a non-soluble calcite to a soluble aragonite. The solids grow because they are taken into solution rather than being bound and contained by surface tension.

   FIG 25:  Another view of Calcites removed from a tower bath

The result is water that has lower surface tension. Water with a low surface tension is referred to as soft water or "wetter water".

FIG 26: End view of a pipe fitted with two generators and four generators


A unit of water with low surface tension will wet a larger area if spilled on a flat surface than water with a high surface tension. Water with low surface tension generally exhibits absorptive qualities.

Since the water treated by the AquaDyn system will have the lower surface tension and absorptive characteristics of soft water, it acts as a host for solids from any source including existing scale. The water will actually experience an increase in the total number of dissolved solids in solution at any one time. This fact is exaggerated by the introduction of copper and silver ions on a continuous basis.

However, the water will have a net reduction in suspended solids, which are normally Calcite’s, as a result of the magnetically induced increase in the number of dissolved solids – the suspended solids are simply “crowded out.”

The net effect is no Calcite scale (since there are no Calcites) because the calcium carbonates will plate out as Aragonite’s, which are water-soluble. The other solids will have a tendency to agglomerate and be discharged through the cyclone as a result of the increased particle size and mass.

 FIG 27:  Water management unit servicing a small Cleaver Brooks boiler

It should be noted that the aragonite crystals produced by the magnetic field generator employed by AquaDyn will in the absence of the field [i.e. the cooling tower bath], revert to a Calcite. Naturally produced Aragonites [which are rare] revert eventually to Calcites also. The magnetically produced Aragonite’s morph down to a calcite in the bath of the cooling tower and they are sparged out of the bath through the cyclone that is employed by AquaDyn. They are then discharged from the system.

The cycle of events is not linear (i.e. magnetic field presence  = Aragonite / absence of magnetic field = immediate production of calcite crystals ready for discharge).  The process is dependent on the total number of hard spots in the water, the total solids contained in the water, the residual effects of the magnetic fields, and the influence of other inductive fields.

FIG 28: View of a scaled boiler tube prior to the installation of an AquaDyn water management system

Continuously Removes Solids and Other Debris

A cooling tower will usually contain suspended solids (sand, clay, etc.) and dissolved solids (calcium carbonate and others). In addition to the cyclone, the systems are fitted with counter flow filters, which remove most of the solids that are about the same specific gravity as the host water, and cartridge filters, when needed, to remove lighter materials such as bug wings etc… There are circumstances under which sand filters are employed as an additional filtration device.



FIG 29: Cyclone (centrifugal separator) utilized to remove heavy solids

FIG 30:  Purge line on a cyclone
The purge system that is programmed into each AquaDyn water management system is designed to be open for a duration of 6-8 seconds and the purge cycle

ranges from every 15 minutes to every four or five hours, depending on the state

of the system when AquaDyn begins their water management system.  A standard AquaDyn system which has a pump rate of 100 gallons per minute would discharge 100gpm/60sec/min X 6 sec  = 10 gal per purge cycle.

The AquaDyn water management system can be designed to discharge to a series of vessels that are constructed in a manner that enables the solids to be trapped and the solid concentrate or solids are removed while allowing for the return of the purge water back to the tower bath for reuse.  In other words, AquaDyn can design a zero water discharge system for locations that require that attention to discharge detail.


Part 3: Cost Savings Information

AquaDyn Service Costs as an Operational Expense rather than a Capital Expense

The AquaDyn system cost can be used as an operational expense rather than a capital expense, which is generally easier for companies to fund. Moreover, the customer can realize net annual savings of $30/ton to $40/ton of cooling capacity that AquaDyn manages.

AquaDyn’s three-, four-, and five-year service contracts include the cost of system installation, weekly site inspections and all maintenance and upgrading that may be required.

AquaDyn’s operating costs are negotiated on a location-by-location basis, since a major portion of our cost is the weekly service expense. The cost for an isolated cooling tower might exceed the usual $2.70/ton/month while a cluster of units that can be serviced during one service call would probably be $2.00/ton/month. The red tape associated with a service call is very important in determining the cost of the water management service.

Cost Comparison Information: – AquaDyn vs. Chemical Technology

Based on a 500 ton Cooling Tower

TYPICAL OPERATING COSTS

BASED ON A 500 TON COOLING TOWER

                                                                        Chemical                                AquaDyn Water

                                                                        Technology                            Management

Chemicals                                                      $    5,000  1                            $           0   2

Compressor Electricity (4¢)             $115,200  3                            $  96,000   4

Water and Sewage                                       $  20,520  5                            $  16,416   6

Tower/Condenser Maintenance                  $    5,500  7                            $           0   8

Tower Electricity (4¢)                                    $    8,076  9                            $    5,854   10

            TOTALS                                             $154,296                               $118,270

Cost per Ton                                                  $  308.59/ Ton                       $  236.54/ Ton 

Annual Gross Savings                                                                      $  36,070

AquaDyn Service Contract                                                              $  16,236

Net Annual Savings                                                                          $  19,834

Net Savings/Ton                                                                                $   39.67/Ton/yr



Please see the endnotes for the suppositions.

           

Chemical Costs

     1.   Chemical Treatment.

Average Cost: $5,000

Chemicals cost an average of $10/ton/yr. in systems operating 6,000 hours per year. Chemicals used include biocide, algaecide, corrosion and scale inhibitors, and scale dispersant. This estimate includes annual costs of field monitoring and chemicals needed to recharge system after periodic bleeding to remove mineral concentrations.

     2.    AquaDyn Treatment.

Cost: 0

Compressor Electricity ($.04) Costs

     3.    Chemical Treatment. 

            Average Cost: $115,200

Notes: The U.S. Department of Energy estimates that a 1/8" buildup of scale on a heat exchange surface will reduce the efficiency by 25%. Cooling towers and condenser sections using chemical treatment of the cooling water inevitably generate scale in the sump and the piping of the chiller and/or heat exchangers. 500 ton X 0.8KWH/ton (conversion rate of electrical to mechanical energy) X 6,000 hrs X $0.04/KWH X 1 (load factor) = $96,000/yr X 120% (20% loss to scale or film) =$115,200.

     4.    AquaDyn Treatment Costs

Cost: $96,000.00

Notes: The AquaDyn physics technology will remove existing scale from the cooling tower sump and the piping. To be conservative, a 10% figure is used for efficiency improvement even though, as noted above, DOE estimates that 1/8" scale on condenser tubes can reduce operating efficiency by 25%. Chiller electricity savings and costs are calculated as $115,200 / 80% = 96.000.

Water and Sewage Costs

     5.    Chemical Treatment. 

Average Cost: $2.40/1,000 gal

          

           Makeup water/Sewage costs

*Evaporation: 0.038gpm/ton X 500ton X 60min X 6,000hrs = 6,840,000gal/yr.

                     Water/sewage costs = $2.40/1,000gal \evaporation costs = $16,416

*Blowdown: 10.0095 gpm/ton X 500 ton X 60 min. X 6,000 hrs = 1,710,000 gal/yr.

                   Water/sewage costs = $2.40/1,000 gal \Blowdown costs = $4,104

 Total Makeup water/Sewage Costs = $20,520.

* These formulas are derived from Perry's Chemical Engineers' Handbook, 6th Edition {50th anniversary edition}

   pp 12-17.

6.    AquaDyn Treatment.

Cost: $16,416.

Notes: The AquaDyn Water Management System will eliminate blowdown that results in water and sewage savings of $4,104.

Tower/Condenser Maintenance Costs

    7.    Chemical Treatment. 

Average Cost: $5,500 per year

Notes Tower maintenance is estimated to require an annual effort of 76 hours to scrape, clean and recoat and 24 hours to disassemble and reassemble the tower defusion plates and the condenser bells.  At a labor rate of $55/hr. this maintenance costs $5,500 per year. No estimates are made for periodic flushing of the entire piping system with muriatic acid and then a neutralizer to reduce scale buildup.

     8.    AquaDyn Treatment.

Cost: 0.

Notes: All maintenance, calibration and water testing associated with the operation of the AquaDyn Water Management System is provided by AquaDyn through its water management contract.

Tower/Condenser Maintenance

     9.    Chemical Treatment. 

 Average Cost: $8,076 per year

 Notes:  Electrical costs associated with the operation of the cooling tower are based on

 a 15 hp motor to drive the pump and a 30 hp motor to drive the cooling fan. These

 assumptions yield a cost of: 45hp X 0.748/hp X 6,000hrs X $0.04/kwh = $8,076.

    10.    AquaDyn Treatment.

 Cost: $5,854 per year

 Notes: The AquaDyn system is expected to reduce operating costs for the cooling

 tower by slightly less than 34 percent. Combining 66 percent of the cost of electricity for

 the existing system and adding the cost of a two horsepower motor to operate the

 AquaDyn system, obtain this estimate. The calculations are: $8,076 X 66% = $5,330/yr

 plus operating costs for the AquaDyn system (2hp X 0.748/hp X 8,760hrs/yr X

 $.040/KWH = $524.00). Total costs are, therefore: $5,330 + $524 = $5,854.



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