Advanced Chemical Technology, Inc. Water Savings Through Cooling Tower Design, Construction and Proper Chemical Treatment Advanced Chemical Technology, Inc. April 5, 2016 Bryan Small Matt Fogle

Overview Water California’s Drought Cooling Tower Design and Functionality Maximizing Cooling Tower Water Savings Alkalinity Programs Acid Makeup Water Pretreatment Cooling Tower Design Considerations

Water Hydrological cycle The universal solvent High specific heat Cheap* Readily available* Safe High specific heat Ability to store large amounts of heat (energy) *Not so much in CA

Water Pure Water What makes water conductive? Non-conductive Salts Gases Metals

Water Water Sources Surface Water Ground Water Low dissolved Solids High Suspended Solids Quality changes through season Ground Water High dissolved solids Low suspended solids Consistent quality

Water Water quality effects water savings pH Conductivity (TDS) Hardness (Ca and Mg) Alkalinity (CO3) Silica Iron, Chlorides, Phosphate, etc.

California’s Drought Entering the 5th year Snowpack at 83% of avg 30% of water supply 25% water conservation mandate still in effect Majority of reservoirs still well below historical averages

California’s Drought

California’s Drought Water Quality Lower quality Varying water sources Higher dissolved solids Lower quality Warmer, shallow water supports algal blooms Increased conductivity Salt water intrusion Parameter 2012 2014 Delta TDS 386 538 +152 Conductivity 617 856 +239 Total Hardness 157 254 +97 Chloride 77 91 +14 Sodium 64 86 +22 Sulfate 102 193 +91 San Diego – Miramar Treatment Facility

Cooling Towers Open loop heat exchanger Hot water returns from chiller Air is used to remove heat from the water through evaporation Cold water returns to chiller to remove heat from refrigerant

Cooling Towers Evaporation in CT concentrates impurities Pure water evaporates Water is removed through tower blowdown Makeup = Evaporation + Blowdown Cycles of Concentration or Concentration Ratio (CR) Determines water savings

Cooling Towers Evaporation determined by size of unit Can change blowdown through increasing CR Reducing blowdown Increases water savings Increases TDS Can lead to scaling

Cooling Towers Water chemistry limits Scale pH Temperature Silica Hardness Alkalinity Scale Reduces efficiency Increases energy costs Damage equipment

Water Savings Through Chemistry 0.01” of calcium carbonate (scale) on heat exchangers reduces efficiency by 10% 500 tons of AC, operating 24/7/365 @ 0.6 Kw/ton and a cost of $0.07/Kw will cost $184,000…10% increase is $18,400 annually Water treatment for that system should cost $6,000 - $12,000 annually.

Water Savings Through Chemistry Water tends to scale or corrode High hardness and alkalinity Tends to scale Low hardness and alkalinity Tends to corrode Three main treatment methods for cooling towers Alkaline program Acid Control Makeup water pretreatment

Water Savings Through Chemistry Alkaline Program Concentrates tower water so it tends to scale Uses chemistry to control/inhibit scale Limiting factors Alkalinity 400 – 600 ppm as CaCO3 Hardness 1200 – 1400 ppm as CaCO3 Parameter 2012 2014 Delta TDS 386 538 +152 Conductivity 617 856 +239 Total Hardness 157 254 +97 Alkalinity 91 122 +31 Chloride 77 +14 Sodium 64 86 +22 Sulfate 102 193 +91 San Diego – Miramar Treatment Facility 2012 Concentration Ratio: 4.4 – 6.6 2014 Concentration Ratio: 3.3 – 4.9 11% Increase in Water Usage (Alkalinity Limiting Factor)

Water Savings Through Chemistry pH control with acid Additional chemical cost Hazardous material Reduces alkalinity, hardness limiting factor Total Hardness Limit 1200 – 1400 ppm as CaCO3 Parameter 2012 2014 Delta TDS 386 538 +152 Conductivity 617 856 +239 Total Hardness 157 254 +97 Alkalinity 91 122 +31 Chloride 77 +14 Sodium 64 86 +22 Sulfate 102 193 +91 San Diego – Miramar Treatment Facility 2014 Concentration Ratio: 3.3 – 4.9 (Alkaline Program) 2014 Concentration Ratio: 4.7 – 5.5 (Acid Program) 12% Decrease in Water Usage vs. Alkaline Program (Total Hardness Limiting Factor)

Water Savings Through Chemistry Makeup water pretreatment Water softening Removes calcium and magnesium from makeup water Eliminates the ability for the water to form scale Dramatically increases cycles of concentration Reverse Osmosis Blending RO water with makeup water to reduce overall mineral concentration

Water Savings Through Chemistry Water Softening of Makeup Water Allows for 10+ CR in cooling tower Not limited by alkalinity No hardness No scale Parameter 2012 2014 Delta TDS 386 538 +152 Conductivity 617 856 +239 Total Hardness 157 254 +97 Alkalinity 91 122 +31 Chloride 77 +14 Sodium 64 86 +22 Sulfate 102 193 +91 San Diego – Miramar Treatment Facility 2014 Concentration Ratio: 3.3 – 4.9 (Alkaline Program) 2014 Concentration Ratio: 4.7 – 5.5 (Acid Program) 2014 Concentration Ratio: 20+ (Makeup Water Pretreatment – Water Softening ) 27% Decrease in Water Usage vs. Alkaline Program 17% Decrease in Water Usage vs. Acid Program (*No Limiting Factors With Soft Water*)

Alkaline Program Pros and Cons Low equipment cost Low chemical cost Simple control system Typically, water treatment chemistry is not corrosive Achieve most significant water savings from 1 – 6 cycles Cons Water savings may be severely limited (dependent on makeup water mineral content) Possibility of scale formation if there is a change in water quality

Acid Program Pros and Cons Increased water savings over non-chemical or alkaline treatment program Low equipment cost Add pH control to system ($500 - $1500) Add acid tank and pump Low acid cost $2.00 - $4.00 per gallon Cons Highly corrosive material Can severely damage equipment if overfed Hazardous for employees More complicated chemistry program than Alkaline

Pretreatment Program Pros and Cons Significant water savings over alkaline or acid program Eliminates the systems ability to form scale which can increase energy costs Cons High upfront equipment cost Water treatment system Filtration Complicated treatment program May require equipment coating or painting to protect metals

Water Savings Considerations Increasing your CR saves water Additional costs to increasing CR Chemical Service Equipment Reduced blowdown can cause accumulation of debris in basin 20+ CR High tower conductivity Mineral rich water Bulk water chemically treated to prevent corrosion Air-Water interface can be corrosive Splash zones can build up minerals Drift becomes mineral rich (can be corrosive)

Water Savings Considerations Downsides to water savings can be addressed Reduced Blowdown Basin sweepers/side stream filtration Mineral buildup in splash zones Wash down/clean these areas more frequently Mineral rich drift Epoxy coat metals in drift zones Coat chiller end bells and tube sheets

Cooling Tower Design Considerations Metallurgy of Tower Galvanized Low cost White rust Stainless Steel High cost High corrosion resistance Composite Not as durable as metal Filtration system Reduces debris in CT Reduces cost of operation (cleaner heat exchanger surfaces) Reduces biocide feed Reduces cost of cleanout Coating End bells and tube sheets Inside and outside CT

Case Study – County of San Diego County Administration Center (CAC) 900 tons of cooling Alkaline program CR = 2.2 High hardness High alkalinity No filtration Stainless steel towers County Operations Center (COC) 2700 tons of cooling Acid Program CR = 4.5 High hardness Centrifugal filtration system with basin sweepers on all cooling towers Stainless steel towers

Case Study – County of San Diego CAC Filtration system installed Piping in CT drift zones coated with epoxy paint Makeup water pretreatment equipment installed (removal of hardness) New controller installed for monitoring pretreatment system and CT control COC Piping in CT drift zones coated with epoxy paint Makeup water pretreatment equipment installed (removal of hardness) New controller installed for monitoring pretreatment system and CT control Acid removed from site

Case Study – County of San Diego CAC (estimated values) Annual water savings of over 600,000 gallons 94% reduction in blowdown 44% reduction in overall water consumption COC (estimated values) Annual water savings of over 1,700,000 gallons 88% reduction in blowdown 20% reduction in overall water consumption

Case Study – County of San Diego Actual values exceeded estimated water savings

Case Study – County of San Diego Cooling tower load conditions were higher than anticipated (verified with water meters after estimates were calculated) Resulted in higher than anticipated water savings Estimated project ROI between two sites was 31 months COC = 18 months, CAC = 55 months With higher than expected water savings, this number is reduced even further

Case Study – County of San Diego State mandated 25% reduction in water usage County of San Diego exceeded this mandate at both sites 4 more sites online now All anticipated to exceed the 25% state mandated reduction in water usage Total water savings to date across all systems is over 7,700,000 gallons At current San Diego water rates, this equates to a monetary savings of over $100,000

Q & A

THANK YOU! ACT has over 20 years as a leader in industrial water treatment throughout California, Arizona and Nevada. For more information on our water treatment services, please visit us at www.actglobal.net. You can also directly contact us at: Bryan Small bas@actglobal.net Matt Fogle mdf@actglobal.net