Grundfos Energy OptimizationWater Pumps

Feras Marish, B.Eng.

What is a Booster Pump?

In Hi-Rise Buildings

Booster installed after the City Meter

Traditionally Designed Booster

Pumps can waste

Grundfos Energy Optimization

Can help you Save your money

HOW DO WE DO IT?

Section 1

Energy Efficiency can be increased via 3 ways:

1) Pump Type Change; Vertical-Multi-Stage Pump vs. Vertical Inline Single Stage

Pump

– VMS requires less horsepower to operate.

– Hydraulic Efficiency is a lot better due to tighter tolerances

2)Technology Change; Variable Speed vs. Constant Speed

3)System Design Change; Proper Sizing

How Do We Do it?

Pump Type Change

Multi-Stage vs. Single-Stage

• Smaller Impeller requires

less Horsepower

• near-perfect geometries

and tolerances

• Internal leakage caused by

pressure differentials within

the pump minimized.

• An enhanced impeller

design reduces eddy flow

and friction losses.

• Laser Welded Stainless

Steel Impeller

Pump Type Change

Vertical Multi Stage Single Stage

• Large Impeller needed for

Pressure Boosting

Application, Larger HP.

• Hydraulic Inefficiencies

due to trimming of

impeller (Internal

Leakage)

• Cast Bronze Impeller;

cannot endure harsh

working conditions

(Cavitation and Erosion)

Pump Type Change

Vertical Multi StageSingle Stage

Design Change

Booster Sizing

• Hunters Curve

• Most hydronic heating systems and Domestic Cold Water (DCW) booster pumps are oversized. This oversizing occurs for several reasons such as;

o Lack of precise designing tools

o Compounding design safety factors

Designed for Maximum Flow

How are D.W. Boosters Sized?

• Characteristics

– Large variations in flow

– Constant Pressure

Actual Water Flow Demand in Multi storey buildings

Typical consumption profile, 24 hours

FLOW RATE SPREAD

88% of the flow

rates are under

50 gpm

The average

flow rate is

32 gpm

ASPE Joins IAPMO and WQRF in Revising Hunter's Curve

• “Such a large-scale statistical analysis of hourly use and flow patterns of

plumbing fixtures common in residential occupancies has never been done,”

Cole said. “The original Hunter model for public use was based

on assumptions only, not data. The Hunter model for private use was

based on morning calls in two hotels and one apartment. The scope of this

project greatly surpasses the original work piloted by Dr. Hunter. We are

excited about the potential results this project may bring forth for more

accurate water supply demand estimates, efficient pipe sizing, and precise

metering.”

• “ASPE is committed to supporting this critical research that will provide our

members with statistically sound information that will assist them in designing

plumbing systems that are even more efficient and cost effective,” stated Jim

Kendzel, ASPE Executive Director/CEO. “The plumbing industry needs to

continually invest in research to be able to provide the public with a safe and

efficient water supply and ASPE is proud to be working with IAPMO and WQRF

in supporting this project.”

DCW Booster are OVERSIZED

Submitted by gpienta@aspe.org on Thu, 05/16/2013 - 13:21

http://aspe.org/node/1267

The Hydraulic Institute recommends operating between 70% and 120% of BEP

B.E.P – Best Efficiency Point

E

f

f

i

c

i

e

n

c

y

Flow

H

e

a

d

70% 120%

BEP

Over-sized

Pump run at

very low

efficiencies

0.1% (Pump Eff.

Measured in

some cases)

Technology Change

Variable Speed vs. Constant Speed

Common Constant Speed Booster

System

Pump running at Constant Speed

An example:

• A fixed speed water supply pump has a Hnom = 50 psi at Qnom

• Water Flow (Demand) is 98% of the time less than Max Flow

• To reduce flow, pressure will need to be increased to 90 psi

Required pressure = 50 psi

Q

H

Reduced

flow

Fixed

speed

Pressure at Fixed speed

pump solution = 90 psi

Excess

pressure

System

Nominal

flow Qnom

Constant speed pump system will result in:

• High energy consumption

• Noise

• Wear and stress on system (Pre-Mature Failure of mechanical components)

• Pressure Reducing Valves

– Extra Cost in the System ($1,500 - $5,000 each / One per

Pump)

– High Maintenance Item ( $1,000 - $4,000 annual

maintenance)

• Pay Money to Increase Pressure

• Pay Money to Reduce Pressure!!!

Where does the Extra Pressure Go?

• The pump is always working generating extra pressure

when there is low demand.

• At NO Flow condition, NO Water Demand, the constant

speed pump will keep working. The impeller rotation

heats up the water to over 50C in some cases (Reported

reaching second floor)

Where does the Water Go?

Required pressure = 50 psi

Q

H

Reduced flow

Fixed

speed

Pressure

at Fixed

speed

pump

solution =

90 psi

Excess

pressure

System

Nominal flow Qnom

Life Cycle Cost (15 year Service Life)

Excerpt from: Optimizing Pump Systems: A Guide for Improved Energy Efficiency,

Reliability & Profitability, Pump Systems Matter and Hydraulic Institute

Percentages will vary based on

application

• Pumping accounts for 10-12% of the world’s energy consumption

• Hydraulic Institute studies have shown that 30% – 50% of the energy consumed by pumps

and pumping systems could be saved through equipment or control system changes

Energy HOGS!

• Non-optimized Systems are

ENERGY HOGS!!

Grundfos FULLY Variable Speed Booster System

Why speed controlled pumps ?

An example:

• A speed controlled pump automatically adapt

the pump performance to the actual need.

• When flow is reduced by low demand the pressure

remains constant 50 psi

Variable speed

Freq.

conv.

M

PI

Controller

Set point

Required pressure = 50 psi

Q

H

Reduced

flow

Fixed

speed

Pressure at Fixed speed

pump solution = 90 psi

Excess

pressure

System

Nominal

flow Qnom

Pressure at Variable speed

pump solution = 50 psi

Does Operational change Help?

Manual Operational changes will not achieve the optimum energy savings for the

following possible reasons:

1. The Pumps are oversized by design

2. The pumps are at end-of-life condition (close to or over 15 years old) the

efficiency is very low (0.1 – 10 %)

3. The existing booster pump system is designed for constant speed operation

which is not suited for the Domestic Cold Water boosting-Variable Flow

application.

An Attempt

to save energy

via Manual

Sequence of

Operation

The Problem with Most Existing D.W.

Boosters?

Energy

Inefficient

Constant speed Over-sized

Inefficient

Pumps

PRE-INSTALLATION AUDIT

POST INSTALLATION AUDIT

Grundfos Accuracy

Building

Existing System

Consumption

(kWh)

Esimated

Consumption

Savings (kWh)

Measured

Consumption

Savings

(kWh)

Consumption

Saving

Discrepancy

(%)

Building 1 198,759 157,357 152,972 2.79%

Building 2 198,567 165,495 171,393 3.56%

Building 3 369,404 342,113 332,814 2.72%

Building 4 237,196 197,867 198,574 0.36%

Building 5 166,112 133,364 131,106 1.69%

Building 6 312,480 268,386 266,282 0.78%

Building 7 154,861 122,490 118,053 3.62%

Building 8 332,277 298,669 291,133 2.52%

Building 9 151,880 137,960 140,108 1.56%

Building 10 142,707 119,297 119,944 0.54%

Building 11 158,795 136,269 132,719 2.61%

Building 12 142,329 140,439 137,527 2.07%

Building 13 175,256 164,548 164,843 0.18%

Building 14 127,932 125,689 124,669 0.81%

Building 15 167,740 165,420 161,031 2.65%

Office Buildings

More Energy

SavingsDomestic Hot Water Pump

Traditional 3-Piece Circulatior

MAGNA – Intelligent Pump

MAGNA – Intelligent Pump

More Energy

SavingsHVAC Pumps

HVAC Pumps

Intelligent HVAC Pumps

Feras Marish, B.Eng.Business Development Manager – Energy

Optimization

Grundfos Canada

905-464-0490

fmarish@grundfos.com