2020 TECHNICAL WEBINAR SERIES
SPEAKER: Peter GaydonHydraulic Institute
MODERATOR: Warren FishNorthwest Energy Efficiency Alliance
www.TheBOC.info
Improving the Energy Consumption of Pumps
April 1, 2020 11:00am Pacific Time
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This presentation is intended for use by the Smart Buildings Center, the Northwest Energy Efficiency Council and its programs. No copy or use of this presentation should occur without the permission of SBC/NEEC and its speakers.
Introducing our Speakers
LEARN. LEAD. SUSTAIN
SPEAKER: Peter Gaydon, Hydraulic Institute
MODERATOR: Warren Fish, Northwest Energy Efficiency Alliance
LEARN. LEAD. SUSTAIN
Learning Objectives
After today’s webinar, you will be able to:
• Calculate pump system power and energy consumption• Describe typical pumping systems in commercial buildings• Explain pump performance curves• Explain how impeller diameter and speed of rotation impact pump
performance• Identify the pump operating point in a system and basic control• Discuss options for pump system optimization• Discuss opportunities with pump efficiency labeling
Optimizing Pumping Systems
What is a Pump
Pump means equipment that is designed to move liquids(which may include entrained gases, free solids, and totallydissolved solids) by physical or mechanical action andincludes at least a bare pump and, if included by themanufacturer at the time of sale, mechanical equipment,driver, and controls.
What is a Pumping System?
Devices interconnected with pipelines, that includes a pump that moves liquid to achieve the intended work or utility
System configuration, liquid, and purpose depends on the application
Moving liquid requires energy and cost money
Pump System Energy Consumption
Life Cycle Cost of Typical Pumping System
Focus on Energy & Maintenance
presents 65% of LCC
Elements of the LCC• Energy – 40 %• Maintenance – 25%• Initial Purchase – 10%• Operating – 10%• Installation & Commissioning – 7%• Environmental cost - 5%• Downtime, Loss of Production – 3%
Focusing on initial cost misses the
big picture
What impacts energy consumption?• System flow (System & control)
• System head (System & control)• (Static, Pressure & Friction)
• Fluid density (System)
• Operating Time (System control)
• Pump/Motor/Drive efficiency (Equipment & System)• At the operating point
Pump System Energy Consumption
Focus on Pumping System!
Power (ℎ𝑝) =𝐻𝑒𝑎𝑑∗𝐹𝑙𝑜𝑤∗𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝐺𝑟𝑎𝑣𝑖𝑡𝑦
𝐶𝑜𝑚𝑏𝑖𝑛𝑒𝑑 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦∗3960
𝑃𝑜𝑤𝑒𝑟 (𝑘𝑊) =𝐻𝑒𝑎𝑑 ∗ 𝐹𝑙𝑜𝑤 ∗ 𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝐺𝑟𝑎𝑣𝑖𝑡𝑦
𝐶𝑜𝑚𝑏𝑖𝑛𝑒𝑑 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 ∗ 0.1022
Pump System Hydraulic Power
Consumption
US Units (gpm & ft)
Metric Units (m & m3/s)
1 hp = 0.746 kWCombined Efficiency – Pump + Motor + Drive
Pump Power Terminology
𝑃 =𝑃𝑢η
• Pu = Pump power output (hp) or hydraulic power or water power (Pw)
• P = Pump power input (hp) (Also known as BHP)• Pgr= Power input to drive system
• Q = Flow (gpm)• H = Total Head (ft)• s = specific gravity
• η = Pump efficiency = 𝑃𝑢
𝑃
• η𝑂𝐴= Overall efficiency = 𝑃𝑢
𝑃𝑔𝑟
𝑃𝑢 =𝑄 ∗ 𝐻 ∗ 𝑠
3960
𝑃𝑔𝑟 =𝑃𝑢η𝑂𝐴
Sample Horsepower Calculations
Question: Determine the Pump Power Input (P):
• Water (70 F)• Flow (200 gpm)• Head (100 ft)• Pump Efficiency (70%)
Head (ft) x Flow Rate (gpm) x (specific gravity)
3960
Head = 100 ft
Flow Rate = 200 gpm
100 ft x 200 gpm x 1.0
3960
Pu (hp) = 5
Pu = 5
η = 0.7
P (hp) = 7.1
P (hp) =
Pu (hp) =
Calculate Pump Output Power (hp)
Pu (hp) =
Calculate Pump Power Input (P)
Energy is:
• Power (kW) times operating hours (h) = Energy (kWh)
• Hours of operation (h) that system runs
• Power into drive system (kW) • Power at operating point(s) – Weighted average
• 1 hp = 0.746 kW
• Largest factor in Life Cycle Cost Analysis
What is Energy Consumption?
Typical Pumping Systems in Commercial Building
Rotodynamic pumps are kinetic machines in which energy is continuously imparted to the pumped fluid by means of a rotating impeller, propeller, or rotor.
- Transfer mechanical energy to the fluid by increasing fluid kinetic energy
- Kinetic energy converted to potential energy in discharge collector
- Impeller can have a vertical or horizontal axis of rotation
- The most common types of rotodynamic pumps are radial (Centrifugal), mixed flow, and axial flow (propeller) pumps, including pumps historically referred to as vertical turbine pumps.
Rotodynamic Pump
Example
Overhung In-line centrifugal pump• Driver (electric motor & VFD
when included)• Coupling• Pump shaft• Bearings/power frame• Mechanical seal/packing• Impeller• Pump casing
Pressure & Head Primer
23 ft =
10 psig =
24.7 psia
23 ftWater 68 °F
0 psig
• Pressure is force per unit area (i.e. pounds per square inch, psi)• Absolute Pressure the pressure exerted by the weight of the air above it at any point on
the earth's surface • Atmospheric or barometric pressure = 14.7 psia at sea level
• Gauge Pressure is the pressure energy of the liquid, relative to the atmospheric pressure.
• Head is the expression of the energy content of the liquid referred to a datum. The measuring unit for head is feet of liquid
1 𝑝𝑠𝑖 =2.31 𝑓𝑒𝑒𝑡
𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝐺𝑟𝑎𝑣𝑖𝑡𝑦
0
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0
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0 10 20 30 40 50 60 70 80 90 100 110 120 130
Pu
mp
Po
wer
& E
ffic
ien
cy
Tota
l Hea
d (
Pre
ssu
re)
Flow Rate
Pump Head Pump Efficiency Pump input power
Efficiency Curve
Pump Curve
Power
RotodynamicPump Curve
Rotodynamic Pump Affinity Rules2 3
1 1 1 1 1 1
2 2 2 2 2 2
Q n H n P n
Q n H n P n
= = =
Where:Q1 =rate of flow at original speed, in m3/h (gpm)H1 =total head at original speed, in m (ft)P1 =pump shaft power at original speed, in kW (hp)n1 =original pump speed, in rpmQ2 =rate of flow at desired speed, in m3/h (gpm)H2 =total head at desired speed, in m (ft)P2 =pump shaft power at desired speed, in kW (hp)n2 =desired pump speed, in rpm
For impeller trimming:• Substitute impeller
diameter (D) for speed (n)• Assumes constant efficiency
• Limit to small trims • Reference published
curve for larger trims
Published Pump Curves
• Head at various trims
• Iso-efficiency lines
• Power lines
• NPSH3 Lines
• Minimum Flow
Pump input power
NPSH3
For impeller trimming affinity rules:• Calculations assumes constant efficiency,
so limit to small trims• For larger trims, reference published
curves• Note max efficiency decreases as the
impeller is trimmed
𝑄2𝑄1
=𝐷2𝐷1
𝐻2𝐻1
= (𝐷2𝐷1)2
𝑃2𝑃1
= (𝐷2𝐷1)3
Variable Speed Pump Curves
0
20
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60
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120
0 5 10 15 20 25 30
Flow (ML/d)
Pre
ssu
re H
ead
(m
)
0
100
200
300
400
500
600
Pu
mp
Po
wer
(k
W)
BEP
84.5%
80%
80%
Min Flow
100%
Speed
80%
Speed
2 3
1 1 1 1 1 1
2 2 2 2 2 2
Q n H n P n
Q n H n P n
= = =
Simplified System Curve
( ) 2
12 CQzzH +−=H – total head (sometimes referred as Total Dynamic Head)z – elevation C - friction coefficient Q – flow rate
Pump and System Curves
Q
H
System Curve-Static Head-Friction
= operating point
H = HeadQ = Flow
Q
H
Pump Curve-Speed-Impeller Dia.
For fixed speed pumps, the operating point is located at the
intersection of the pump and system curves.
H
Q
Pump & System CurveConstant Speed Pump Selection considerations
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Pu
mp
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ffic
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Tota
l Hea
d (
Pre
ssu
re)
Flow Rate
Pump Head Pump Efficiency Pump input power
Efficiency Curve
Pump Curve
Power
RotodynamicPump Curve
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Pu
mp
Eff
icie
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(%
)
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l Hea
d (
Pre
ssu
re)
Flow Rate
Pump Head System Curve 1 Pump Efficiency
Operating Point - 83% at Best Efficiency Point
Efficiency Curve
Pump Curve
System Curve 1Pumps Operate at the Intersection the Pump and System Curves
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mp
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l Hea
d (
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Pump Head System Curve 2 Pump Efficiency
Operating Point - 29% Efficiency at reduced flow
Efficiency Curve
Pump Curve
System Curve2
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mp
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l Hea
d (
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ssu
re)
Flow Rate
Pump Head System Curve 1 System Curve 2 Pump Efficiency
Operating Point - 83% at Best Efficiency Point
Operating Point - 29% Efficiency at reduced flow
Efficiency Curve
Pump Curve
System Curve 1System Curve2
• The system design impacts the pump’s operating efficiency
• The system design and flow/head requirements should be used to select the correct pump
• When misapplied an efficient pump can operate inefficiently
• Smaller pump with lower best efficiency will operate at higher efficiency is system 2
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mp
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l Hea
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ssu
re)
Flow Rate
Pump Head System Curve 1 System Curve 2 Pump Efficiency Small pump Small pump efficiency
Operating Point - 83% at Best Efficiency Point
Operating Point - 29% eff "big" pump, 60% eff "small" pump
Efficiency Curve
Pump Curve
System Curve 1System Curve2
"Small" Pump Curve
"Small" Pump Efficiency Curve
HVAC Pump Application Examples
• Many installed HVAC systems used constant speed pumps and 3-way valves
• Inefficient pumping energy design
• Excess conditioned water flow is bypassed –wasting pumping energy and helping cause chiller low ∆T syndrome
Traditional control of a constant speed constant volume pumping system
Control of a constant speed variable volume pumping system• Many installed HVAC systems used constant speed
pumps and 2-way valves
• Inefficient pumping energy design
• Excess pump head created by throttling – wasting pumping energy – this excess pressure negatively influences balance of other zones
• Eliminates excess flow to save energy vs. three - way valve
• Can adapt to changing capacity demands achieved with two way valves
• Should be selected for higher efficiencies at part-load: • lower energy consumption
• reduced operating costs, and
• improved equipment reliability.
Variable speed variable volume pumping systems
Variable Flow System
Example of a variable flow heating system
• (Pump 1) The constant speed pump would ride the system curve at full speed as zone demand decreases
• Causes the pump to operate away from BEP• Wastes energy
• (Pump 2) The variable speed will reduce speed as zone demand decreases.
• Allows the pump to better match the system demand, operating closer to BEP
• Saves energy when less heating zones are required.
Introduction to Pump System Optimization
“The process of identifying, understanding and cost effectively eliminating unnecessary losses while reducing energy
consumption and improving reliability in pumping systems, while meeting process requirements, minimizes the cost of ownership over the economic life of the pumping systems.”
What is System Optimization
Source: Pump System Optimization: A Guide to Improved Energy, Efficiency, Reliability and Profitability (HI 2018)
Optimization Starts with System Assessment
PSAP certification outlines requirements• Outlines tasks and knowledge
• Comprehensive exam
• Tests the knowledge of candidates related to knowledge requirements.
• Provides assurance that candidates have experience and knowledge required to conduct pump systems assessments
More Information at:http://www.pumps.org/Certification/PSAP.aspx
http://estore.pumps.org/Guidebooks/PSABOK.aspx
Pump System Assessment Professional (PSAP) Certification
• Variety of solutions available to reduce energy consumption & improve reliability
• No single option is the solution to all optimization efforts and typically involves a combination of options
• Solutions fall into 3 broad categories1. Reduce system head (static and dynamic)
2. Reduce system flow rate or operating time
3. Modify or replace equipment
4. Improve maintenance and operation practices
Options for System Optimization
Reduce static head• Raise supply tank level or pressure
• Lower product tank level or pressure
• Siphon design, make a siphon work for you
Reduce friction head• Eliminate throttling flow control
• Increase pipe size and use low resistance valves
• More direct pipe routing
• Install parallel pipe lines
• Clean fouled equipment
1. Reduce System Head
Throttling Control
Higher flow rates than needed require more energy to be added at the pump
• Recirculation or bypass flow control
• Unregulated flow through heat exchangers
• Number of operating pumps not adjusted for seasonal changes in temperature
• In batch operations, if fill and drain times can be extended, flow rates can be reduced
• Turn off pumps when flow is not needed
• Isolate unnecessary flow paths
2. Reduce System Flow Rates
Bypass Control
Modifications to Pumps
• Replace grossly over-sized pumps
• Trim pump impeller
• Change pump speed
• Smaller “jockey” pump installed for periods of lower flow rates
• Parallel or series pump operation vs. single large pump
Modifications to Motors
• Install variable speed drive
• Replace
3. Modify System Equipment
• Start-up and shutdown procedures
• Protective devices (low power, low pressure, minimum flow, etc.)
• Installation and commissioning check lists
• Condition monitoring practices
• Impeller adjustments
• Lubrication
• Alignment
• Proper seal packing & sizing
• Operate per requirements in operating manual
4. Improve Operation and Maintenance Practices
Pump System Optimization Exercise
• Pump not sized properly• Operates at 367 gpm, but BEP is 250 gpm• Water at specific gravity of 1.0• Cost of electricity is $0.09/kWh• Operates 4000 hours per year
• Optimization options are: 1. Throttle the existing valve2. Trim the impeller3. Add a VFD4. New pump sized for the application
Case Flow rate (gpm) Head (ft) Pump Efficiency (%) Valve drop (PSID) Pump Power (hp) Annual Energy Cost ($)Original 367 173 64 21
Throttle valve 255 242 85 72Trim impeller 252 98 70 10Reduce speed 250 96 70 10
New Pump 250 95 86 10
Exercise: Calculate pump input power and annual energy cost for each optimization scenario below.
Exercise AnswerCase Flow rate (gpm) Head (ft) Pump Efficiency (%) Valve drop (PSID) Pump Power (hp) Annual Energy Cost ($)
Original 367 173 64 21 25 $6,711
Throttle valve 255 242 85 72 18.3 $4,913Trim impeller 252 98 70 10 8.9 $2,389Reduce speed 250 96 70 10 8.7 $2,336
New Pump 250 95 86 10 7 $1,879
𝑃 =𝑄 × 𝐻 × 𝑠
3960×η
𝐴𝑛𝑛𝑢𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑐𝑜𝑠𝑡 ($) = 𝑃 (𝑘𝑊) × 𝑟𝑎𝑡𝑒 × ℎ𝑜𝑢𝑟𝑠
DOE Regulation & Voluntary Industry LabelingEnabling utility rebates for energy efficient pumps
New Efficiency Ratings For Pumps Enable Deemed Incentives
• Department of Energy - Energy Conservation Standard
• Hydraulic Institute Energy Rating
What does the regulation mean to you?• Certain clean water pumps manufactured or imported into the US must
comply to minimum performance levels
• Generally covers 5 types of clean water pumps, between 1-200 hp, flow ≥ 25 gpm , Head ≤ 459 ft, 1800 & 3600 RPM
• The rules use a holistic approach considering the pump, motor and VFD (when applicable)
• Based on new “Pump Energy Index (PEI)” metric
• Constant Speed Pumps – PEICL
• Variable Speed Pumps – PEIVL
• PEICL/VL ≤ 1.00 required to comply
• 25% of the least efficient bare pumps have been removed from the market
DOE Regulations for Pumps – IT’S THE LAWPEI used to calculate power savings
Learn more - Free Webinar: https://estore.pumps.org/Overview-of-The-US-DOE-Energy-Conservation-
Standard-and-Test-Procedure-for-Clean-Water-Pumps-1-Part-On-Demand-Webinar-P3153.aspx
• Covers bare pumps, pumps sold with a motor, and pumps sold with a motor and continuous or non-continuous controls
• Two different types of PEI dependent on if the pump is sold with continuous or non-continuous (variable speed) controls:
Pump Energy Index (PEI)
Label Contains
• Brand Name
• Model Number
• Equipment Type
• Nominal Speed
• PEI
• Load Type
• Range available
• ENERGY RATING
HI Energy Rating Label
Links back to ER.PUMPS.ORG database
for verification
Additional data available in
the Energy Rating
Database
er.pumps.org
Learn more - Video: https://www.youtube.com/watch?v=T5wzVS5IaDY&feature=youtu.be
Hydraulic Institute (HI) Energy Rating (ER)
• Industry metric designed for labeling program
• Calculated based on PEI of the pump
• Describes percent power savings over baseline minimally complaint pump (1.0)
ER = (1.0-PEI) * 100
PEI ER % Power Savings over Baseline
0.95 5 5%
0.50 50 50%
Calculating Energy SavingsEstimated Annual
Power Savings Over Baseline
Estimated Cost Savings
= x Motor HP
x x OpHrs/yr
Power Savings
= x Cost of Power
=
= $/yr
kWh/yr
Voluntary Labeling & Deemed Incentives
Public Database: http://er.pumps.org
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time for … Q&A
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Washington & Oregon
• Smart Buildings Center - http://www.smartbuildingscenter.org/tool-library/
Idaho• University of Idaho – Integrated Design Lab - http://www.idlboise.com/content/tool-loan-library-free-resource-idaho-power-company-customers
California
• Pacific Gas & Electric - http://www.pge.com/pec/tll/
• Sonoma County - http://sonomacounty.ca.gov/General-Services/Energy-and-Sustainability/Tool-Lending-Library/
• Southern California Edison - https://www.sce.com/business/consulting-services/energy-education-centers
• San Diego Gas & Electric - https://www.sdge.com/energy-innovation-center/tool-and-book-lending-library
New York
• CUNY Building Performance Lab - http://www.cunybpl.org
Tool Lending Library Locations
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www.theboc.info877-850-4793 (toll free)
BOC National Partner Network
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➢April 22nd: Security & Resiliency in Smart Buildings
➢May 14th: HVAC Controls Including Demand-Control Ventilation
➢September 23rd: Financing Energy Efficiency Projects
➢October 21st: Technical Aspects of Renewables & Storage
2020 Webinar Topics
