Energy Management for Energy Management for Pretreatment OperatorsPretreatment Operators

Getting Started?Getting Started?

Evaluate Your ConsumptionEvaluate Your Consumption• Review energy bills

– actual use, demand, power factors, surcharges, number of meters…

• Map energy use & costs over time– monthly, weekly, daily….

• Look for trends– seasonal trends, diurnal cycles, special events, changes in production rates…..

Understanding your Understanding your BillsBills• Actual Use: actual power draw • Demand Charges: highest 15 minute draw, maximum transmission requirements

• Power Factor (Reactive Power): energizing current for certain equipment

• Fuel/Green Power Surcharge• Other miscellaneous trackers and charges

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

Feb-0

6

Mar-0

6

Apr-0

6

May-0

6

Jun-0

6

Jul-0

6

Jul-0

6

Aug-0

6

Sep-0

6

Oct-0

6

Nov-0

6

Dec-0

6

Jan-0

7

Feb-0

7

Mar-0

7

Apr-0

7

May-0

7

Jun-0

7

Jul-0

7

Aug-0

7

Sep-0

7

Oct-0

7

Nov-0

7

Dec-0

7

Mo

nth

ly C

ost,

$

Date

Electrical Demand Charges vs. Usage Charges

Cost Due to Usage, $

Cost Due to Demand, $

Annual Profile of Natural Gas Usage & Cost in West Lafayette, INAnnual Cost = $831.72

Average Monthly Cost = $69.31

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0

August-07 September-07

October-07 November-07

December-07

January-08 February-08 March-08 April-08 May-08 June-08 July-08

Date

Mo

nth

ly U

sag

e (

Th

erm

s)

&

Co

st,

$

0

200

400

600

800

1000

1200

1400

Heati

ng

Deg

ree D

ays,

HD

D

Natural Gas Usage, Therms

Cost, $

Heating Degree Days, HDD (West Lafayette, IN)

Survey Equipment and Survey Equipment and FacilitiesFacilities• List equipment: motors, compressors, heated tanks, boilers, lights, spray guns, vents, chillers..

• Note characteristics: size, age, load, condition…..

• Look at use: what time of day, how long, what process, well matched….

• Building: windows, HVAC, doors, insulation….

• Evaluate water use

Survey WW OperationsSurvey WW Operations

• Best TSS range for treatment • Minimum DO for best operations• Minimum velocity to achieve goal• Equipment (motors, pumps, tanks, VFDs)

• Monitoring & recording • Regulatory requirements

Energy Savings from Dissolved Energy Savings from Dissolved

Oxygen ManagementOxygen ManagementActual Set point Savings

DO DO Fraction Percent

2 2 - -

3 2 1/8 12.5

4 2 2/8 25

5 2 3/8 37.5

6 2 4/8 50

7 2 5/8 67.5

8 2 6/8 75

Opportunities for ImprovementOpportunities for Improvement

• Reduced load through water conservation

• Decrease operating hours/off peak usage

• Wastewater treatment practices

• Use gravity flow instead of pumps

• Equipment size, type, condition

Optimize MotorsOptimize Motors

• High efficiency motors• Proper size (70-90% load)• Use variable frequency drives• Proper pulley drive alignment & non-slip belts

• Decrease idle time• Replace rather than rewind

Specifications Standard Motor (rewound once)

High Efficiency Motor

Premium Efficiency Motor

Efficiency of Motor 86.5% 93.2% 95.1%

Purchase/Installation Costs

$1,965 $2,225 $2,375

Connected (kW) 32 30 29

Annual Energy Use (kWh/yr)

283,308 262,941 257,688

Energy Reductions (from standard)

N/A 7.2% 9.0%

Energy Costs ($/yr) $11,059 $10,264 $10,059

Cost Savings for Energy ($/yr)

N/A $795 $1,000

Demand Savings ($/yr) N/A $392 $493

Total Cost Savings N/A $1,187 $1,493

Simple Payback (yrs) N/A 1.9 1.6

Motor: 50 HP, 75% load, Peak 5,380 hrs , Off-peak 3,380 hrs (obtained from MotorMaster database (NEMA Table 12-12)

See the See the System, System,

Not just the Not just the ComponentComponent

Signs of InefficienciesSigns of Inefficiencies

•Designed for different function•Partially closed discharge valve•Discharge bypass line that stays open•Multiple parallel pumps with the same number always running•Noise at the pump (or elsewhere in system)•Excessive maintenance costs

Boilers and Steam Boilers and Steam SystemsSystems• Insulate condensate return pipes & reservoir

• Inspect & repair steam traps• Use exhaust heat to preheat make-up water or combustion air

• Proper maintenance– Fire/water tubes cleaned?– Fuel air ratio properly adjusted?

Steam Wasted from Leaking Steam Wasted from Leaking Traps Traps @ @ 100psi, 80% boiler efficiency

Source: Energy Management Handbook-Fifth Edition Size of

orifice (in)Steam wasted

per month (lbs)Energy lost per month (MMBtus)

Cost/month ($11/MMBtu

)

1/8 52,500 58 $635

3/16 117,000 128 $1,416

¼ 210,000 231 $2,415

5/16 325,000 359 $3,933

3/8 470,000 517 $5,687

7/16 637,000 701 $7,708

1/2 835,000 919 $10,104

Compressed Air Compressed Air SystemsSystems• Monitor and repair leaks• Evaluate how & where it is used• Deliver only where needed• Store in accumulator tanks• Run only during production hours• Use the lowest operating pressure possible• Fresh air intake• Harvest waste heat and use elsewhere• Minimize air loss during condensate release

Example: Energy Loss from Example: Energy Loss from Leaks Leaks

• 8,760 hours of operation• 10 leaks, 1/16” • 90 psi • Energy loss= 36,646 kWh/yr• Cost ($0.06/kWh) = $2,200/yr

Lighting SystemsLighting Systems

• Use energy efficient lamps, ballasts and fixtures

• Install fixtures at the proper height• Use task lighting• Use the proper light levels• Use occupancy sensors

Example: Savings from Motion Sensor (33% savings)• 25 fixtures, F96, T12, 60W• 8,760 hrs = 30,222 kWh/yr• Energy cost = $0.06/kWh• Lighting cost = $1,813/yr• 2,920 hrs = 10,074 kWh/yr• Savings = $604/yr

Ventilation & Dust Ventilation & Dust CollectionCollection• Vent to outside air only as needed• Minimize the volume of air vented• Use fans only during production • Filter and return ventilation air during heating season

• Preheat return air in an air-exchanger

• Use variable speed drive

Chillers & Cooling Chillers & Cooling TowersTowers

• Use variable speed drive controls on fans and pumps

• Use energy efficient fan and pump motors

• Consider raising the chiller water temperature

• Harvest heat for use elsewhere

Best Practices Workshops• Motors• Fans• Pumps• Compressors• Lighting

• Steam• Process Heating• HVAC• Sustainability• http://www.mep.purdue.edu/events/default.aspx#ees

Upcoming Events

• Fan Workshop• June 11, 2010 08:00AM-04:00PM Vincennes Univ. 850 College Ave. JASPER, IN 47546

• Steam System• June 22, 2010 08:00AM-04:00PM

Vincennes Univ. JASPER, IN 47546

• June 23, 2010 08:00AM-04:00PM 6640 Intech Blvd.

• Indpls, IN 46268

Guidebook for Public Utilities• Intended for Water and Waste Water Utilities

• Energy Management documentation • Project identification and prioritization

• Developing a systematic approachhttp://www.epa.gov/region1/eco/energy/pdfs/guidebook_si_energymanagement.pdf

Questions, Comments, Need Help?

Ethan RogersManager EES317-275-6817earogers@purdue.edu