Benchmark Your Water/Wastewater Facilities to...
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Benchmark Your Water/Wastewater Facilities to Achieve Energy Savings Noah L. Mundt, P.E, CEM December 3, 2013
Transcript of Benchmark Your Water/Wastewater Facilities to...
Benchmark Your Water/Wastewater Facilities to Achieve Energy Savings
Noah L. Mundt, P.E, CEM
December 3, 2013
Increasing EE in Water/Wastewater Pump
Systems
Welcome & Introduction
• APS Pump & Blower Program. – Overview.
– Why pumps & blowers for energy efficiency?
– Average energy metrics for water/wastewater
• Relation to Governor’s Energy Office. – Water Energy Partnership in Arizona (WEPA).
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Meeting Agenda
• Pump Basics. • Pumps & Systems. • Pump Optimization Techniques. • WW System & Energy Components. • WW System Benchmarking & Evaluation. • EE Measures in WW Systems. • EE Programs & Incentives.
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Why Pumps for Energy Efficiency?
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7% 10%
40%
25%
10% 3% 5% Installation
Pump
Energy
Maintenance
Operating
Downtime
Environmental
Optimizing Pumps Systems, Hydraulics Institute & Pump Systems Matter
Why Pumps for Energy Efficiency?
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Optimizing Pumps Systems, Hydraulics Institute & Pump Systems Matter
7% 10%
40%
25%
10% 3% 5%
About 40% of the pump lifecycle cost is spent for energy
Pumps in Water & Wastewater
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• Water Distribution Pumps – Booster Station : 700 – 1,200 kWh/MG – Well Pumps: 1,000 – 1,800 kWh/MG
• Waste Water Treatment Plants – System :
1,000 – 3,500 kWh/MG
Pumps in Water & Wastewater
facilities account for (1/7) of AZ state energy consumption.
Common Pump Types
• Well Pumps
• Booster Pumps
Deep Well Turbine
Submersible
Centrifugal
Turbine
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Deep Well Turbine Pumps
• Most common in well pumping applications where water is to be pumped out of several hundred feet of depth.
• Driving mechanism is located over the surface and a column shaft connects the motor to the pump.
• Pumps often have several stages.
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Submersible Well Pumps
• Commonly used in situations where water tables fluctuate considerably over the season and noise is a factor.
• Often used in conjunction with booster pumps so as to provide a positive suction head.
• Motor and pumping components located beneath the ground surface.
• Requires less maintenance.
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Centrifugal Booster Pumps
• Commonly used as booster pumps in water/wastewater systems.
• Rotational energy of the impeller converted to pressure energy of water.
• Can be used for vertical as well as horizontal water pumping.
• High Efficiency over range of operating conditions.
• Also used in applications such as chilled water, power plants and industrial pumping.
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Turbine Booster Pumps
• Commonly used in booster stations with multiple pumps.
• Priming not needed.
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Pump System Components
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Prime Mover
Piping/Control Valves for flow
Column Shaft/Tube
Pump Bowl Assembly
Pump Impeller
Electric Motor
Diesel/Gas Engines
Air System
Radial Flow
Axial Flow
Flow Control in Pumps
Four (4) most common types of flow control in pumping systems are:
• On/Off controls with a switch / timer.
• Manual Throttling Valve flow control.
• Discharge Flow Control Valve.
• Variable Frequency Drives.
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Principle of VFD
=
pf*120ω
Change in frequency leads to change in the synchronous speed of motor shaft
As per the Pump Affinity Laws:
=
designdesigndesign dd
NN
QQ 111 *
3
1
3
11 *
=
designdesigndesign dd
NN
PP
Pump Affinity Laws.
2
1
2
11 *
=
designdesigndesign dd
NN
HH
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Decreasing flow will
reduce energy usage by the
cube
Pump Affinity Laws
0
0.2
0.4
0.6
0.8
1
1.2
0 0.2 0.4 0.6 0.8 1 1.2
Flo
w,
Hea
d &
Po
wer
Rat
io
Speed Ratio
Flow Ratio
Head Ratio
Power Ratio
For a given impeller diameter:
Speed decreased by 20%, power reduced by
49%
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0
0.2
0.4
0.6
0.8
1
1.2
0 0.2 0.4 0.6 0.8 1 1.2
Flo
w,
Hea
d &
Po
wer
Rat
io
Speed Ratio
Ideal
Actual
100HP VFD Operation
17 EE of VSD Systems
VFD Operational Regime is between
40% - 95%
0
0.2
0.4
0.6
0.8
1
1.2
0 0.2 0.4 0.6 0.8 1 1.2
Flo
w,
Hea
d &
Po
wer
Rat
io
Speed Ratio
Ideal
Actual
10HP VFD Operation
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VFD Operational Regime is between
60% - 95%
VFD Energy Savings
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0
0.2
0.4
0.6
0.8
1
1.2
0 0.2 0.4 0.6 0.8 1 1.2
Flo
w,
Hea
d &
Po
wer
Rat
io
Speed Ratio
Constant Speed
Ideal
Actual
Energy Savings
Pump OPE Determination
=
IHPsgHQ
OPE *3960**η
where:
ηOPE – Operational Plant Efficiency
Q – Baseline flow rate (GPM) from pump test.
H – Total Head – hs + hd
sg – Specific Gravity – 1.0 for water
IHP – Input Horse Power – Input kW/0.746
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Meeting Agenda
• Pump Basics. • Pumps & Systems. • Pump Optimization Techniques. • WW System & Energy Components. • WW System Benchmarking & Evaluation. • EE Measures in WW Systems. • EE Programs & Incentives.
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Pump Curves
Performance Curves, Turbine Well Pump, Goulds
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System Curves
• A fluid flow system can be characterized with a system curve.
• The system curve establishes the relation between the head and flow in the system.
( )QfH =
CBQAQH ++= 2
where: headofcomponentfrictiondynamicA )(α
headofcomponentdrawdownB αheadofcomponentstaticC α
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Single Pump System Curve
0
100
200
300
400
500
600
700
800
900
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm)
System Curve
350 HP Turbine Well Pump
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Duty/Operational Point
0
100
200
300
400
500
600
700
800
900
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm) Constant Speed System Curve
Operating Point
350 HP Turbine Well Pump
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Types of System
• Open Loop Systems aka Static Head Dominated Systems.
o Primary effect of these systems is to overcome the static head.
o Examples include pump systems in deep well applications, boiler feed water systems, water/fire protection systems in high rise buildings
• Closed Loop Systems aka Friction Dominated Systems.
o These systems have water circulating in a closed loop with the help of a pump
o Examples include HVAC CHW, HW, CW pumps, hydronic heating systems, etc.
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Static Head Dominated Systems
0
100
200
300
400
500
600
700
800
900
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm) Constant Speed System Curve
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Static (Hs)
Friction (Hf)
Hs >>Hf
Friction Dominated Systems
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0
100
200
300
400
500
600
700
800
900
1000
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm) Constant Speed System Curve
Friction (Hf)
Hf >>Hs
Varying Discharge Flow Rate
• Changing the System Curve. o Static Head Elevation changes.
o Discharge Flow Control Valve Adjustment.
o Manual Throttling Valve Adjustment.
• Changing the Pump Curve. o Impeller Size Adjustment.
o Variable Frequency Drive Installation.
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Effect of Elevation Changes
0
100
200
300
400
500
600
700
800
900
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm) Constant Speed System Curve
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Decreasing the static head results in more flow from the pump due to the
system curve being shifted right
Effect of Flow Control Valve
0
100
200
300
400
500
600
700
800
900
1000
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm)
Pump Curve System Curve
Desired Flow (flow with CV)
Normal Operating Point (flow w/o CV)
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Effect of Flow Control Valve
0
100
200
300
400
500
600
700
800
900
1000
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm)
Pump Curve System Curve
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Head loss across CV.
Effect of Manual Throttling Valves
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0
100
200
300
400
500
600
700
800
900
1000
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm) Constant Speed System Curve
Manually throttling the inlet valve increases the resistance in the system
and shifts the curve to the left
Impeller Size Adjustment
0
100
200
300
400
500
600
700
800
900
1000
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm) Constant Speed Operating Condition
Decreasing impeller size shifts pump curve down.
Large Impeller
Small Impeller
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Effect of VFD
0
100
200
300
400
500
600
700
800
900
1000
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm) Constant Speed Operating Condition
Decreased VFD set point
60 Hz
55 Hz
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0
100
200
300
400
500
600
700
800
900
1000
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm) Constant Speed Operating Condition System Curve
Effect of VFD
Pump Operating Point with VFD
Normal Operating Point
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Effect of VFD/Impeller Size Adj.
0
100
200
300
400
500
600
700
800
900
1000
0 200 400 600 800 1000 1200
Hea
d in
Fee
t
Flow (gpm) Constant Speed Operating Condition System Curve
Allows the pump to operate on the system curve.
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Multiple Pumps
• Pumps in Parallel.
• Pumps in Series.
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Output Flow from System
Output Flow from System
Pumps in Parallel
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Flow (GPM)
Hea
d (f
t.)
Pump#1 Pump#1,2 Pump#1,2,3
As more pumps come on, flow output increases for the same TDH delivered
Pumps in Parallel
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Flow (GPM)
Hea
d (f
t.)
Steep System Curve
Fractional Increase in flow output from pumps due to
a steep system curve
The increased flow delivered from the pumps in parallel depends on the
system curve.
Pumps in Parallel
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Flow (GPM)
Hea
d (f
t.) System Curve
1 2
3
System Curve Development
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Flow (GPM)
Hea
d (f
t.) System Curve-2
Shape of the system curve is a function of static and friction
heads in the system.
System Curve-1
System of Pumps – Case Study – Booster Pump Station
• Baseline Condition – (5) Booster pumps operating in parallel at constant speed, throttling flow control.
• Proposed Condition – (3) Booster pumps with VFDs.
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Baseline Pump Station System
0
50
100
150
200
250
300
0 2000 4000 6000 8000 10000 12000 14000
Sys
tem
Hea
d (
in f
eet)
System Flow (in GPM)
System Static Head
Booster pump # 1 operational
Booster pump # 1 & 2 operational
Booster pump # 1,2 & 3 operational
Booster pump # 1,2,3 & 4 operational
Booster pump # 1,2,3,4 & 5 operational
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Baseline Pump Station System
0
50
100
150
200
250
300
0 2000 4000 6000 8000 10000 12000 14000
Sys
tem
Hea
d (
in f
eet)
System Flow (in GPM)
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System Operating Regime.
Proposed Pump Station
0
50
100
150
200
250
300
350
400
450
500
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Hea
d (
ft)
Gallons per Minute (GPM)
Proposed Pump Curve
System Curves
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Sequencing strategy for the pump
operation can be obtained from these
results.
Pumps in Series
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Flow (GPM)
Hea
d (f
t.)
Pump#1
Pump#1,2
Pump#1,2,3
As more pumps come on, system TDH increases for the same flow output.
Pumps in Series
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Flow (GPM)
Hea
d (f
t.)
Steep System Curve
Large increase in head with little increase in
flow output
Pumps in Series
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Flow (GPM)
Hea
d (f
t.)
Relatively small increase in head with increase in flow due
to shallow system curve.
Pump Optimization EE Measures
Wide variety of EE measures to optimize pump operation and its energy use. These include –
– Pump Efficiency (OPE) Improvement • Bowl Replacements
• Impeller Replacements
– Column Tube/Shaft/Piping Replacements (reduce friction losses) – Right Sizing Pumps – Pump schedule changes (EE/DR) – Pump Sequencing. – System Improvements (match with design conditions). – Prescriptive EE Measures–
• Variable Speed Drives.
• High Efficiency motors.
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Pump Optimization Considerations
Pump Optimization
Pump Size
Annual Operational
Hours
Existing Efficiency
Energy Prices
Utility Incentives
System Constraints
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Time for a Small Break!!
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Meeting Agenda
• Pump Basics. • Pumps & Systems. • Pump Optimization Techniques. • WW System & Energy Components. • WW System Benchmarking & Evaluation. • EE Measures in WW Systems. • EE Programs & Incentives.
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Typical Wastewater Processing
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Major Energy Consuming Equipment
Primary Treatment
• Pumps • Gravity Driven Flow/Solid Seperation
Secondary Treatment
• Pumps • Blowers/Aerators • Process Equipment (Solids)
Tertiary Treatment
• Pumps • Lighting
Pumps & Blowers
account for 80% - 90% of the total plant
energy!
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Pumps in WW Treatment Plants
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Pump Systems
- Influent Pump(s) - Booster Pump(s)
Pump Types: - Centrifugal. - Submersible.
Typical Discharge Pressure Levels = 15-30 psig.
- Booster Pump(s)
Pump Types: - Centrifugal. - Turbine.
Typical Discharge Pressure Levels = 10-20 psig.
- Booster Pump(s)
Pump Types: - Centrifugal. - Turbine.
Typical Discharge Pressure Levels = 0-20 psig.
Primary Pumps Secondary Pumps Tertiary Pumps
Blowers/Aerators
• Blowers/aerators are aeration devices that are used for introducing air into the treatment ponds/basins
• The ingested air helps in growing bacteria that could assist in the biological digestion of the raw sewage .
• Responsible for 50-70% of total plant energy consumption
www.spencerturbine.com www.hellotrade.com 57
Blowers in WW Treatment Plants
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Blowers
Positive Displacement Blowers - Uses reciprocating/rotary mechanism - Typical Blower Eff. = 45% - 65% - Flow Range = 5-50,000 scfm - Pr. Range = 1-14 psig - Min flow = 50% of design
MS Centrifugal Blowers - Uses centrifugal mechanism - Typical Blower Eff. – 50% - 70% - Flow Range = 500-30,000 scfm - Pr. Range = 4-14 psig - Min flow = 60% of design
MS Centrifugal Blowers with VFDs - Uses centrifugal mechanism with variable frequency drives - Typical Blower Eff. – 60% - 70% - Flow Range = 500-30,000 scfm - Pr. Range = 4-24 psig - Min flow = 50% of design
SS Centrifugal Blowers - Uses centrifugal mechanism - Contains only 1 stage - Typical Blower Eff. – 70% - 80% - Flow Range = 500-30,000 scfm - Pr. Range = 4-24 psig - Min flow = 45% of design
HS Turbo Blowers - Uses turbo blowers with integrated variable frequency drive mechanisms - Typical Blower Eff. – 70% - 80% - Flow Range = 400-10,000 scfm - Pr. Range = 4-35 psig - Min flow = 50% of design
Aerator Types
Wastewater Engineering Treatment and Reuse – Metcalf and Eddy
Aerator
Horizontal Axis
Surface Submerged
Vertical Axis
Surface Submerged
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Aerator Types
Aeration System Transfer Rate lb Oxygen/hp.h
Standard Field
Surface low-speed 2.5-3.5 1.2-2.4 Surface low-speed with draft tube 2.0-4.6 1.2-2.1 Surface high-speed 1.8-2.3 1.2-2.0 Submerged turbine with draft tube 2.0-3.3 1.2-1.8 Submerged turbine 1.8-3.5 1.2-1.8 Submerged turbine with sparger 2.0-3.3 1.2-1.8 Horizontal rotor 1.5-3.6 0.8-1.8
Wastewater Engineering Treatment and Reuse – Metcalf and Eddy 60
Air Diffusers
• Diffusers are used for diffusing the air from the blower into the aeration basins.
• The type of diffuser determines the transfer efficiency of the air injected into the basins.
• Diffuser performance thus plays an important role in the aeration efficiency of WW plant
Air Diffuser Types 61
Diffuser Types
Wastewater Engineering Treatment and Reuse – Metcalf and Eddy 62
Porous
• Disk • Dome • Membrane • Panel
• State of art, current trend and offer higher oxygen transfer efficiencies
Non-Porous
• Orifice • Slotted Tube • Static Tube
• These aeration devices offer low oxygen transfer efficiencies
Others
• Jet Aerators • Aspiring
Aerators • U-tube
Aerators
• These aeration devices offer low – medium oxygen transfer efficiencies
Aeration Diffusers
Porous Diffusers
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Porous Diffusers
Disc Typical SOTE is 25%-35%
Dome Typical SOTE is 27%-37%
Membrane Typical SOTE is 26%-33%
Panel Typical SOTE is 38%-43%
Meeting Agenda
• Pump Basics. • Pumps & Systems. • Pump Optimization Techniques. • WW System & Energy Components. • WW System Benchmarking & Evaluation. • EE Measures in WW Systems. • EE Programs & Incentives.
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WW System Benchmarking
• ENERGY STAR benchmarking. Web link – http://www.energystar.gov • Other Benchmarking Metrics.
– Typical Range is 1,000 – 3,500 kWh/MGD
– These metrics are a function of treatment processes. Typical ranges for
• Primary = 1,000 – 1,200 kWh/MGD
• Secondary = 1,200 – 1,800 kWh/MGD
• Tertiary = 2,000 – 3,500 kWh/MGD
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WW System Evaluation
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Small Plants = ≤ 2.0 MGD Medium Plants = 2.0 – 20.0 MGD
Large Plants = > 20.0 MGD
EPA Publication
Meeting Agenda
• Pump Basics. • Pumps & Systems. • Pump Optimization Techniques. • WW System & Energy Components. • WW System Benchmarking & Evaluation. • EE Measures in WW Systems. • EE Programs & Incentives.
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Conventional EE Measures
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Pumping Systems
• Pump Eff. Improvements
• Right Sizing Pumps • Pump Schedule
Changes • Pump Sequencing • System
Improvements • VSDs • HE Motors
Mechanical Aeration Systems
• Conventional Retrofits
• Adjustable Weirs to change submergence
• Aerator type retrofits
• Aerator Cycling • Multi-Impeller
Aerators • DO Control
Blower Aeration Systems
• Right Sizing Blowers
• Dedicated Blowers for Channel Aeration
• Diffuser Configuration
• Intermittent Aeration
• DO Control • Single stage
centrifugal blowers with IGV and VDV
• Fine Bubble Diffusers
Solids Processing Systems
• UV Disinfection • Membrane
Bioreactors • Biological Nutrient
Removal (Aeration cycling)
• Hyperbolic Mixers
Innovative & Emerging EEMs
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Pumping Systems
• Power Factor Correction
• VFD Sequencing • Optimized Rotor &
Stator Design • Low Friction
Bearings • Dynamic Rotor
Balancing • Ultra Premium
Efficient Motors
Mechanical Aeration Systems
• Automated DO Control
• Respirometry • Off-Gas Analysis • SymBio process • BIOS
Blower Aeration Systems
• Automated DO Control
• High Speed Gearless (Turbo) Blowers
• Ultra fine porous membrane diffuser panels
• Diffuser Foul Prevention
Solids Processing Systems
• Anaerobic Digestion
• Pulsed Large Bubble Mixing
Meeting Agenda
• Pump Basics. • Pumps & Systems. • Pump Optimization Techniques. • WW System & Energy Components. • WW System Benchmarking & Evaluation. • EE Measures in WW Systems. • EE Programs & Incentives.
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APS Solutions for Business
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• Pump Test Program
• Tests for the Overall Plant Efficiency of individual pumps & blowers
• APS covers half the cost of testing
• Technical Assistance
• Cash incentives to help cover the cost of studies, could possibly include pump system studies or WWTP audits.
• Prescriptive Incentive Application
• High-efficiency motor replacement
• Installation of VFD (some restrictions apply)
• Custom Incentive Application
• All other energy efficiency measures not covered by the prescriptive application
• $0.09/first year kWh saved up to 75% of incremental cost
• Must pass a TRC test so submit a pre-application
APS Solutions for Business
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• Additional equipment rebates offered in our program include:
• Lighting
• Cooling
• Refrigeration
• Whole Building
• Will look at any proven energy savings under our custom program
Program Requirements
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• APS customer on qualifying rate
• Qualifying rates include E-32, E221, all commercial retail rates
• > 40% load factor ~ 3,000+ operating hours per year, per pump
• >15 hp
Individual Pump Testing
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• 50% off Testing for APS customers for Qualifying Pumps and Blowers
• Tests determine Overall Plant Efficiency (OPE) – standard measurement of pump efficiency
• Measures head, flow and energy demand • Result shows the hydraulic energy out as a percentage of
electric energy input
• Regular testing allows owners to • Track the performance of their pumps, • Identify problems before they become critical • Plan for repairs • Identify candidates for improvement
Next Steps
• Submit a request form • Gather information on pumping and blower system
• Photographs of piping system are helpful
• Existence of test ports
• Pumps approved for testing • Test Contractor contacts to schedule tests • Test performed • Review Results • Get quote for repairs • Submit a pre-application for incentives
• Notification required prior to repair work being performed
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Q & A
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