BUILDING TECHNOLOGIE

February 6, 20

ASRAC Pumps Working Group

Metric Construct Details
2

Metric Applicability to Pump Configurations

Pump Configuration

Bare Pump Bare Pump + Motor Bare Pump + 

Metric Coverage

Bare Pump Does not include motor efficiency Does not d

losses 

Bare Pump +

Motor (w/ std. motor)

Does not d

losses 

Bare Pump +

Motor +

Controls (w/ std. motor and controls) (w/ std. controls)

Pump Motor

Pump Control M
3

Covered Product Metric

Bare Pump

Efficiency

or Energy

Use

Motor

Efficiency

or Energy

Use

‘Pump’

Efficiency or

Energy Use

=
4

Possible MetricPump Energy Rating (PER): equally weighted average electric inpu

(P1) to the ‘pump’ measured (or calculated) at the motor input or, 

present, controls input, over a specified load profile (100%, 75%, 5

25% of Best Efficiency Point (BEP) flow at nominal speed).

• For bare pump or pump+motor, a

part‐load by throttling through p

at rated speed.

• For pump+motor+controls, achie

load by reducing speed and corre

specified system curve shape.

PER = 0.25(P1BEP) + 0.25(P10.75 BEP) + 0.25(P10.5 BEP) + 0.25(P

Notes:Denominator could be included in metric

Rating point of 25% may not be appropriate/feasible for throttled configurations
5

×

standardized motor

efficiency and part load

curve

MOTOR

pump performan

from pump test 

speed

Bare Pump Testing

×

standardized controls

performance

Controls

Example of Motor Choice:

• If standard motor: AC Induction, NEMA Design B, open enclosure.

• Could use next HP above brake horsepower at 120% BEP or 

defined motor rating.

• Poles would be based on speed at which pump is being rate

• If standard full load motor efficiency is used, it would be based on 

standards (assuming the motor is a type covered by Federal stand

• Could use full load motor efficiency for all points or develop stand

part‐load curves.
6

×

manufacturer motor

efficiency at full and part

load

A MOTORB MOTOR PUMP

Bare Pump + Motor Testing

Ma

pai

with 

Ma

me

p

standardized controls

performance

Controls ×

pump performance

data from pump

test at rated speed

standardized controls

performance

Controls ×
7

pump performance from pump

test at rated and reduced speed

× motor/drive performance A data

B

VFD MOTOR

Controls MOTOR PUMP

Bare Pump + Motor + Controls Testing

Ma

pai

mo

Ma

me

p

co

Alternative• Could develop standard system curve/factors to use for this configuratio

and testing the motor and controls might not be required.
8

 ܲܧܴ ൌ 	 ߱଴.ଶହ ௉బ.మఱ ఎ೘೚೟೚ೝ,బ.మఱ ൅ ߱଴.ହ଴ ௉బ.ఱబ ఎ೘೚೟೚ೝ,బ.ఱబ ൅ ߱଴.଻ହ ௉బ.ళఱ ఎ೘೚೟೚ೝ,బ.ళఱ ൅ ߱஻ா Where:

• ωi = weighting at each rating point (could use 0.25 for all rating points or other 

weights),

• Pi = measured input power (brake horse power) to bare pump at rating point i,

- [Based on throttling along pump curve]

• η motor,i = motor efficiency at rating point i,

- Bare Pump: could use default values for a standard motor;

- Bare Pump + Motor: could use motor manufacturer provided values or full loa

all rating points

• i = load points corresponding to 0.25 (25% of BEP flow), 0.50 (50% of BEP flow

BEP flow), and BEP (BEP flow) (or other determined points)

 Note: as indicated above, the formula does not have to use part‐load effic

for the motor – it could use the nominal full‐load efficiency for all loading 

Bare Pump/Bare Pump + Motor Equation
9

 ܲܧܴ ൌ

	߱଴.ଶହ

௉బ.మఱ

ఎ೏ೝ೔ೡ೐,బ.మఱ

൅ ߱଴.ହ଴ ௉బ.ఱబ ఎ೏ೝ೔ೡ೐,బ.ఱబ ൅ ߱଴.଻ହ ௉బ.ళఱ ఎ೏ೝ೔ೡ೐,బ.ళఱ ൅ ߱஻ா௉ 

 Where:

• ωi = weighting at each rating point (could use 0.25 for all rating points 

determined weights),

• Pi = measured input power (brake horse power) to bare pump at ratin

- [based on reducing speed along or correcting to a specified system curve]

• η drive,i = combined motor and control efficiency at rating point i,

- [could use default values, which would be provided in test procedure]

• i = load points corresponding to 0.25 (25% of BEP flow), 0.50 (50% of 

0.75 (75% of BEP flow), and BEP (BEP flow) (or other determined poin

 Note: as indicated above, the formula does not have to use part‐lo

efficiency values for the drive – it could use a single efficiency valuloading points

Bare Pump + Motor + Controls Equation
10

Example of Metric Application

Note: The example on the following slides is provided for the lim

purpose of demonstrating the potential application of the PER m

does not represent a decision by DOE on an appropriate metric o

level for the products to be addressed by the pumps working gro

 Values used to compare an example pump to the example calculated 

level are for illustration purposes only and should not be considered 

representing recommended values.

 The comparison of the example PER metric to the MEI metric is prov

demonstrate the results of the calculation, and does not represent a

by DOE of the relative merits of one approach over the other.
11

 The efficiency level for a given pump could be set by selecting a target MEI level, taking into acc

baseline motor efficiency, and using those to calculate minimum rating (PER) required for each 

of Ns and Q.

 ܲܧܴா௙௙.௅௘௩௘௟ ൌ ߱଴.ଶହ ∗ ௉೓೤೏ೝೌೠ೗೔೎,బ.మఱ ఎ೛ೠ೘೛,బ.మఱ	∗ఎ೘೚೟೚ೝ,బ.మఱ + ߱଴.ହ଴ ∗ ௉೓೤೏ೝೌೠ೗೔೎,బ.ఱబ ఎ೛ೠ೘೛,బ.ఱబ	∗ఎ೘೚೟೚ೝ,బ.ఱబ ൅ ߱଴.଻ହ ∗ ௉೓೤೏ೝೌೠ೗

ఎ೛ೠ೘೛,బ.ళఱ	∗ఎ೘

߱஻ா௉ ∗

௉೓೤೏ೝೌೠ೗೔೎,ಳಶು

ఎ೛ೠ೘೛,ಳಶು	∗ఎ೘೚೟೚ೝ,ಳಶು

 Where

• P	hydraulic,	i is hydraulic power (HP) at each of the loading points. This is a measured value for each p

• ߟ݉ݎ݋ݐ݋,݅ is the efficiency of a minimally compliant motor (Federal standards) that is of the appropria

given pump.

 If full load efficiency is used at all load points, each ߟ݉ݎ݋ݐ݋,	i can be represented by ߟ݉ݎ݋ݐ݋

 This is the same efficiency that would be applied when calculating an individual pump’s PER 

• ߟ௣௨௠௣,஻ா௉ is a target value that is a function of specific speed and flow (as in MEI approach)

 ߟ௣௨௠௣,௜ are target values that may be some fraction of ߟ௣௨௠௣,஻ா௉

 Target ߟ௣௨௠௣ values would not have to be met individually. Rather, the pump efficiency values a

calculations that will contribute to the overall PEREff.	Level that a pump would have to meet.

 For a pump that does not meet the required PER, the manufacturer could choose to improve hy

OR choose to manufacture the pump with a motor or control system that makes it more efficien

baseline.

How a metric could be constructed: Bare Pum
12

 ݑ݌ߟ݉݌, BEP can be calculated the same way as in MEI, as a function of fl

specific speed.

 ݑ݌ߟ݉݌ at 75%, 50%, and 25% can be calculated as a percentage 

• In the EU, pump efficiency at 75% BEP flow must be 94.7% of ݑ݌ߟ݉• Using a subset of HI data (ESFM pump, 4 pole), DOE analyzed par

efficiency as a percentage of BEP efficiency:

• The results, in the form of population average values, are as follow

- At 75% BEP flow, ݑ݌ߟ݉݌,0.75 is 95% of ݑ݌ߟ݉݌, BEP

– Efficiency as a percent of ݑ݌ߟ݉݌, BEP was independent of flow and fairly in

specific speed

– Agrees with EU value

- At 50% BEP flow, ݑ݌ߟ݉݌,0.50 is 78.5% of ݑ݌ߟ݉݌, BEP

– Estimated ݑ݌ߟ݉݌, 0.50 by fitting 2nd order polynomials to the 75%, 100%, a

efficiency data provided by HI.

– Efficiency as a percent of ݑ݌ߟ݉݌, BEP was independent of flow, fairly indep

specific speed, but showed a larger standard deviation than at 75% BEP 

(data 0.50 ,݌݉ݑ݌ߟ estimating

- 25% BEP flow: No data available; this flow point is omitted for this an

Setting Target Values
13

How efficiency levels could be set: Bare PumpsWith ݑ݌ߟ݉݌, 0.50 and ݑ݌ߟ݉݌, 0.75 defined as (0.785 x ݑ݌ߟ݉݌, BEP) and (0.950 x 

ߟ

respectively, and using full load motor efficiency for all points, the PEREff.

equation can be simplified to:ܲܧܴா௙௙.௅௘௩௘௟ ൌ 	

1

௥௢௧௠௢ߟ

ൈ ߱଴.ହ଴

ܲ௛௬ௗ௥௔௨௟௜௖,଴.ହ଴

0.785	 ൈ 	ߟ௣௨௠௣,஻ா௉

+߱଴.଻ହ

ܲ௛௬ௗ௥௔௨௟௜௖,଴.଻ହ

0.950 ൈ 	ߟ௣௨௠௣,஻ா௉

+߱୆୉୔

ܲ௛௬ௗ௥௔௨௟௜௖,

ߟ௣௨௠௣,஻ா

Where:

ݑ݌ߟ݉݌, BEP in this example is from the MEI surface, using flow and specific s

• If this approach is used, the actual value of ݑ݌ߟ݉݌, BEP could be determined by the C‐v

Level” that is ultimately selected as a result of the standards analysis.

Please Note: the values of 0.785 and 0.950 are preliminary and are used for demo

purposes only. If this approach is used for the rating metric and standard, the sele

actual values for these factors would be made based upon further analysis.
14

Example Scenario and CalculationsGiven the Following Theoretical Pump and Parameters• Flow: 880 GPM

• Specific Speed: 1500

• PBEP = 30.99 HP (Shaft), 26.0 HP (Hydro)

• P0.75 = 27.67 HP (Shaft), 22.4 HP (Hydro)

• P0.50 = 24.64 HP (Shaft), 17.6 HP (Hydro)

• ߟMotor, Default = 93%

• Load Point Weight = 1/3 [even]

ܲܧܴ௖௟௔஼௨௟௔௧௘ௗ ൌ	߱଴.ହ଴

ܲ଴.ହ଴

௥௢௧௠௢ߟ

൅ ߱଴.଻ହ

ܲ଴.଻ହ

௥௢௧௠௢ߟ

൅ ߱஻ா௉

ܲ஻ா௉

௥௢௧௠௢ߟ

ܲܧܴ௖௟௔஼௨௟௔௧௘ௗ ൌ 	

1

0.93 ൈ

1

	ܲܪ	29.86 ൌ ܲܪ30.99 ൅ ܲܪ27.67	 ൅ ܲܪ24.64 ൈ 3

84.04% = BEP ߟ

80.98% = 0.75 ߟ

71.50% = 0.50 ߟ
15

Example Scenario and CalculationsNow we can calculate potential efficiency levels and see how the example 

ratings would compare to the prospective C‐value or PER at each MEI leve

ܲܧܴா௙௙.௅௘௩௘௟ ൌ 	

1

௥௢௧௠௢ߟ

ൈ ൈ ߱଴.ହ଴

ܲ௛௬ௗ௥௔௨௟௜௖,଴.ହ଴

0.785	 ൈ 	ߟ௣௨௠௣,஻ா௉

+߱଴.଻ହ

ܲ௛௬ௗ௥௔௨௟௜௖,଴.଻ହ

0.95 ൈ 	ߟ௣௨௠௣,஻ா௉

+߱୆୉୔

ܲ

ܲܧܴா௙௙.௅௘௩௘௟ ൌ 	

1

0.93 ൈ

13 ൈ

1

ߟ௣௨௠௣,஻ா௉

ൈ

17.6.785

+

22.4

.95

+

26.0

1

PERCalculated: 29.86

ߟ pump, BEP = 84.04%

Passing C‐Value for this Pump: 123.87

MEI Level C‐Value ߟPump, BEP PEREff. Level

10 134.0 73.92% 34.940 128.8 79.15% 32.670 124.8 83.10% 31.180 123.2 84.71% 30.590 121.0 86.95% 29.7

These results demoncalculated PER for th

pump would comparexample PER efficieneach MEI cutoff levewith the C‐value cuto

the same pump.