Evaporative Cooling CondensersWater Efficiency

and You

Executive SummaryWater Misalignment• Current Water Practices are

unsustainable

• We face– Epic Drought– Pressure like never before on water

• Current WT industries method of delivery sets incorrect incentives– Maximize

• the sale of high margin “Specialty “ product

– Minimize• “Service “ Time

– Almost Ignore• Water and energy use

In the end, the current services delivery method simply ignores the key issues and costs customers more to operate chiller system than should be the case

Resources Wasted• Water

– Excessive Water• Make up • Bleed

– Excessive & Dangerous Chemical• Antiscale• Biocide• Acids

– Excessive Utility Use• Electrical Use

– Chiller inefficient Kw / Tn

• Process management– Staff assigned no / low value activities

• Daily water testing

– Important information not communicated• H/E

– Approach, Heat Flux, Etc

• Tower efficiency• Atmospheric conditions

– Wet bulb, dew point, humidity

– Out of spec conditions not reported until damage is done vs with in seconds

Getting Started• No Cost to Client

– Water Samples provided to SWS LLC• City & Tower

– System Information• Cost

– Water, Sewer, Power, Descaling– Tns total system design– % Load On Line

» Fall, Winter, Spring, Summer» Days in each season

• Output with in 2 weeks– Savings available, Cap Ex, Op Ex

• Pilot is available• Process guarantee

– $ savings will be delivered– Water will be saved– System will operate with less scale than is currently the case– System will operate with less corrosion than is currently the case– System will operate with less energy than is currently the case

Preface - Drought

Houston – We Have A Problem

Preface - Inefficiency

No Water From Water Project

Reservoirs are Drying Up

Preface – Surface Water

Preface – Ground Water

Preface - Food Prices

PrefacePeople, Food, Energy – All Need H2O

Preface – Energy Cost Up

Executive SummaryToo Many Big Straws in The Milkshake

Help Do Your Part to Help Us Help You Save 1,000,000,000 GPY

Evaporative Condensers

• Evaporative condensers reject energy from the hot, high pressure compressor discharge refrigerant to the ambient air thereby causing a change in state from vapor to liquid - Condenser

• Water from the basin is pumped to the top of the unit and sprayed down over the outside of the coils as ambient outside air is drawn or blown through the unit by fans.

• As the water pours over the coils and evaporates into the air stream• the exterior heat exchanger surface tends to approach the outside

air wet bulb temperature• energy is transferred from the high temperature refrigerant to the relatively cooler water.

• Nearly saturated air leaves the top of the condenser at a temperature lower than the saturated condensing temperature (SCT), i.e., the saturation temperature corresponding to the pressure inside the condenser.

• The refrigerant then drains from the condenser to the system’s high-pressure receiver.

• The evaporative condenser is mainly a wet bulb sensitive device

Distribution is Critical

System Capacity

• Provided by Manufacturer– Nominal Volumetric Air Flow Rate– Nominal ( Base )Heat Rejection Capacity – Heat Rejection Adjustment Factor - HRAF

• Outside air wet bulb• Ammonia Condensing temperature

Actual Capacity =NHRCHRAF

50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 800.0

200.0

400.0

600.0

800.0

1000.0

1200.0

1400.0

1600.0

Evaporate Condenser Capacity in Tons Holding

Pressure = 160 vs Wet Bulb Temp

Impact of Wet Bulb on Capacity

50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 800.0

200.0

400.0

600.0

800.0

1000.0

1200.0

1400.0

1600.0

Evaporate Condenser Capacity in Tons Holding

Pressure = 160 vs Wet Bulb Temp

Impact of Head Pressure on Spend

150 155 160 165 170 175 180 185 190 195 200 205 210 $650,000.00

$700,000.00

$750,000.00

$800,000.00

$850,000.00

$900,000.00

$654,149.50

$682,903.32

$711,657.14

$740,410.97

$761,976.34

$790,730.16

$819,483.98

$848,237.81

$884,180.09 R² = 0.998225571220224

$ / Yr. Condenser Energy Consumption vs Condenser Pressure1000 Tns at $0.11 / KwHr

Get the Water Chemistry Right

Proper Water Chemistry Allows Higher Cycles

2 4 6 8 -

2,000,000

4,000,000

6,000,000

8,000,000

10,000,000

12,000,000

14,000,000

Annual Water Use 500 Tn Chiller

Carbonate Based Scales• 6/18 of common scales in cooling applications are

associated with Carbonate / BiCarbonate– Calcite– Aragonite– Witherite– Strontianite– Calcium Oxalate– Stederite

• Eliminate this with H+

CO3-2 + 2H+= CO2 + H20 0 00

Condensafe II

In the past Today danger

Carbonate Based Scales• 4/18 of common scales in

cooling applications are associated with Sulfate– Anhydrite– Gypsum– Barite– Celestite

• Eliminate this by not feeding H2SO4

CO3-2 + 2H+= CO2 + H20 0 00

Condensafe II

In the past Today danger

Condensafe II• Synthetic• Functional replacement for H2SO4• On June 18, 2008

– Dr. Robert Scheuplein, Toxicologist and Veteran Director of the Office of

Toxicology Sciences at FDA’s Center for Food Safety and Applied Nutrition.• Dr. Scheuplein has assessed that the active ingreadient in Condensafe II is “Generally Recognized as Safe

(GRAS) in accordance with FDA assessment guidelines.

• Condensafe product formulations– carry a triple zero Hazardous Materials Information System Score– An A rating with regards to required PPE– Are 100% biodegradable in 30 days or less per EPA, Design for the Environment, – OECD and Hach Reactor method guidelines and meet or exceed stringent Direct Release Guidelines for 10 day

bio-degradation.– The entire family of SAFE products

• are non-regulated by the – US  D.O.T., – CANADIAN TDG, IMO and IATA.

• are classified as non-voc, non-corrosive, non-mutagenic, and non-toxic. • show no potential for the generation of carbon dioxide under NIOSH 7903, OSHA & ACGIH testing protocols.

All Good Cooling Inhibitors Contain Common Building Blocks

– BZT• BZT is a corrosion inhibitor and/or yellow metal deactivator based on 1,2,3-

benzotrizole.– BZT prevents corrosion  of yellow metals such as copper, copper alloys, bronze, and other

metals.– BZT inhibits the corrosion of steel, cast iron, cadmium and nickel alloys under certain

conditions.– BZT reduces the corrosive influence of copper ions on various metals.

– HEDP• HEDP is an organophosphoric acid corrosion / scale inhibitor.

– HEDP can chelate with Fe, Cu, and Zn ions to form stable chelating compounds.– HEDP shows excellent scale and corrosion inhibition effects under temperature 250 .℃– HEDP has good chemical stability under high pH value, hard to be hydrolyzed, and hard to be

decomposed under ordinary light and heat conditions.– HEDP acid/alkali and chlorine oxidation tolerance are better than that of other

organophosphoric acids (salt).– HEDP can react with metal ions in water systems to form hexa-element chelating complex,

with calcium ion in particular.

– PBTC• PBTC acts as a crystal modifying agent and threshold inhibitor for calcium and other

metal salts. – PBTC is widely used in industry as a sequestering agent and calcium carbonate scale inhibitor.– In systems that utilize oxidizing microbiocides, such as bromine, PBTC exhibits superior

stability under oxidizing conditions compared to other organophosphonate compounds.

– Silica Control Polymer• ACUMER 5000 is a proprietary multifunctional polymer with a molecular weight of

5000 that provides outstanding silica and magnesium silicate scale inhibition.– ACUMER 5000 prevents silica-based scale formation by dispersing colloidal silica and by

preventing magnesium silicate scale formation at heat transfer surfaces

Alternatives

• Do Nothing• Dolphin and or Magnets

– Relies on Low Cycles• Wastes Water• Deposits• Corrosion

• Softeners– Improper water chemistry results in corrosion

• Other Water Treatment Companies– Low degree of monitoring– Disincentive to provide service

Traditional Water Treatment

• Monitored– Conductivity– pH

• Controlled– pH– Conductivity– Antiscale pump on and off

Dolphin

• Controls nothing• Tower is bled to keep

– Cycles Low– Water Use High

• Essentially once through cooling

Softeners

Softeners are not recommended for galvanized towers

• Historically, maximum service life was obtained by maintaining the chemistry of the circulating water at an essentially neutral state (pH of 6.5 to 9.0) and allowing the natural formation of a protective, light crystalline film on the zinc surface which retarded the formation of white rust.

• While there is still some disagreement on the actual cause of the recent increase in reported cases of "white rust", various water treatment experts are concluding that some of the newer, higher alkaline, treatment chemistries actually inhibit the formation of protective films on the galvanized surface and thus allow the development of white rust.

• There are also indications that soft water (less than 30 ppm total hardness), when combined with these high pH conditions, can exacerbate the problem.

We Use Water More Effectively

Nereus On Line Chemistry

• Conductivity– Controls cycles of concentration

• pH– Controls alkalinity / LSI / Scale

• ORP– Controls biocide feed– Biological control

• Antiscalant– Controls scale

• Ca• Si• Fe

Nereus On Line Meters

• Make Up– Water Use and cost

• Bleed– Sewer discharge and cost

• Recirculation– Supply to Heat Exchangers

• Temperature– Air Dry– Air Wet bulb– Heat exchanger supply water– Heat exchanger return water – Refrigerant condensing temperature

• Chemical inventory levels• Chemical feed rate

Nereus Auxilary

• Corrosion coupons– System metallurgy

• Biological Testing– Total Aerobic Count– Sulfate Reducing Bacteria– Mold– Fungus

Nereus Calculations• Tower

– Efficiency and efficiency vs design– Approach and approach vs design– Delta T and delta T vs design

• Water– $ / Day, Month, Yr– $ vs budget Day / Month / Yr– Yr over Yr

• Sewer– $ / Day, Month, Yr– $ vs budget Day / Month / Yr– Yr over Yr

• Chemical– % Tank level– $ / Day, Month, Yr– $ vs budget Day / Month / Yr– Yr over Yr

Nereus Calculations• Refrigeration tns on line• Refrigeration as a % of design max• Cost / Tn of refrigeration for

– Water actual / actual vs budget / Yr vs Yr– Sewer actual / actual vs budget / Yr vs Yr– Chemical actual / actual vs budget / Yr vs Yr– Power actual / actual vs budget / Yr vs Yr

• Refrigeration Efficiency– Kw / Tn refrigeration actual / actual vs budget / Yr vs Yr

Nereus vs Old School

We Use Water More Effectively

Getting Started• No Cost to Client

– Water Samples provided to SWS LLC• City & Tower

– System Information• Cost

– Water, Sewer, Power, Descaling– Tns total system design– % Load On Line

» Fall, Winter, Spring, Summer» Days in each season

• Output with in 2 weeks– Savings available, Cap Ex, Op Ex

• Process guarantee– $ savings will be delivered– System will operate with less scale than is currently the case– System will operate with less corrosion than is currently the case– System will operate with less energy than is currently the case

Appendix

• Chiller / Condenser Facts• Measuring• Definitions• Chillers• Fouling• Chiller Efficiency• Improving Chiller Efficiency• Typical Water Treatment Problems• Pitting

• Inability to remove heat effectively– Higher head

pressure

Fouling• 240 ton chiller

– Greg Bush Regional Services Lead for Americas• SAP GFM Data Center Services• Regional Energy Manager for Americas

– In the case of SAP at $0.15 kWH – $5,600.00 a year in wasted electricity per degree approach

fowling.  This is a meter verified number.• Chiller in study has efficiency of .65 Kw per ton annualized.

EPA statement said a 1000 ton chiller at $0.11 per kWH is $10,000.00 a year of

wasted energy per degree fouling

Typical Problems Encountered

• Tower Basin– Calcium deposits– Corrosion Tubercle

• Tubercle removed

• Under Deposit Corrosion

• Corrosion Perforation– Under Deposit Corrosion

Pitting

• All forms of corrosion, with the exception of some types of high-temperature corrosion, occur through the action of the electrochemical cell.

• The elements that are common to all corrosion cells are:– An anode where oxidation and metal loss occur, – A cathode where reduction and protective effects occur,– Metallic and electrolytic ( system water ) paths between the anode and

cathode through which electronic and ionic current flows,– A potential difference that drives the cell.

• The driving potential may be the result of differences between the characteristics of dissimilar metals, surface conditions, and the environment, including chemical concentrations.

Pitting• Pitting corrosion is a localized form of corrosion by which cavities or

"holes" are produced in the material. • Pitting is considered to be more dangerous than uniform corrosion

damage because it is more difficult to detect, predict and design against.• Corrosion products often cover the pits.

– A small, narrow pit with minimal overall metal loss can lead to the failure of an entire engineering system.

– Pitting corrosion, which, for example, is almost a common denominator of all types of localized corrosion attack, may assume different shapes. 

• Pitting is initiated by: – Localized chemical or mechanical damage to the protective oxide film; water chemistry

factors which can cause breakdown of a passive film are acidity, low dissolved oxygen concentrations (which tend to render a protective oxide film less stable) and high concentrations of chloride (as in seawater) 

– Localized damage to, or poor application of, a protective coating – The presence of non-uniformities in the metal structure of the component, e.g. nonmetallic

inclusions.

• Theoretically, a local cell that leads to the initiation of a pit can be caused by

– an abnormal anodic site ( under a deposit ) surrounded by normal surface which acts as a cathode,

– or by the presence of an abnormal cathodic site surrounded by a normal surface in which a pit will have disappeared due to corrosion.

Theory

• Water Chemistry– Lack of proper water treatment chemistry allows deposits to occur– Ca, Mg, Fe

– Deposits cause corrosion

– Corrosion products cause more deposits / corrosion with out proper treatment

Observations

• Corrosion

• Corrosion Products

• Corrosion products covered with scale

• Scale is chips off and anode is formed

• Small anode

• Combined with large cathode

• Pitting is expected