ASRAC Pumps Working Group Metric Construct Details BUILDING TECHNOLOGIES PROGRAM February 6, 2014 – revised 3/5/14
Metric Applicability to Pump Configurations Pump Configuration Bare Pump Bare Pump + Motor Bare Pump + Motor + Controls Pump Pump Pump Motor Motor Control Does not include Does not describe control Bare Pump motor efficiency losses or benefits Metric Coverage Bare Pump + Does not describe control Motor losses or benefits (w/ std. motor) Bare Pump + Motor + (w/ std. motor Controls (w/ std. controls) and controls) 2
Covered Product Metric Bare Pump Motor Controls Energy Use = ‘Pump’ Efficiency Efficiency Efficiency Efficiency or or Energy or Energy or Energy Use Use Use 3
Possible Metric Pump Energy Rating (PER) : equally weighted average electric input power (P1) to the ‘pump’ measured (or calculated) at the motor input or, when present, controls input, over a specified load profile (100%, 75%, 50%, and 25% of Best Efficiency Point (BEP) flow at nominal speed). PER = 0.25(P1 BEP ) + 0.25(P1 1.1BEP ) + 0.25(P1 0.75 BEP ) + 0.25(P1 0.5 BEP ) • For bare pump or pump+motor, achieve part-load by throttling through pump curve at rated speed. • For pump+motor+controls, achieve part- load by reducing speed and correcting to a specified system curve shape. Notes: Denominator could be included in metric Rating point of 25% may not be appropriate/feasible for throttled configurations 4
PER Options No Denominator Denominator Form Weighted average of Weighted input of pump input power at pump input power at several load points normalized by pump several load points hydraulic output power, a reference pump efficiency, or other value Units kW, Btu, or HP Dimensionless* Standard Strong function of flow Weak function of flow and specific and specific speed speed Pros Representative of the More comparable across pumps of energy consumption of different sizes/specific speeds; that pump in the field Similar to EEI approach in EU Cons Not comparable across No reference pump efficiency in US, so pumps of different difficult to set; other denominator flows/specific speeds options may not be logical (discussed on next slide) *May vary based on denominator chosen 5
Denominator Options Denominator Pros Cons This value gives no indication of the efficiency of the pump - two pumps Power consumption with equivalent part-load of same pump in an N/A performance and different uncontrolled system efficiencies at BEP would have the same rated value. Reference shaft Results in value between 0 Inherently requires designation of power for minimally and 1. minimally compliant pump (i.e., compliant bare pump Clearly indicates performance MEI). May over- or under-represent with minimally of a pump relative to a the baseline efficiency for some compliant motor baseline. pumps. Market average shaft Locks in the metric to the power with performance of pumps in the Indicates performance of a minimally compliant market at a given point in time. pump relative to the market. or market average Doesn’t limit metric values between motor 0 and 1. Accounts for differences in Tested pump’s pump efficiencies between Lower PER rating for smaller pumps hydraulic power at models. because lower capacity equipment BEP Has similar rated values for is inherently less efficient. pumps of different sizes 6
Bare Pump Testing × × MOTOR Controls standardized motor standardized controls pump performance data performance efficiency and part load from pump test at rated curve speed 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 other defined motor rating. • Poles would be based on speed at which pump is being rated. • If standard full load motor efficiency is used, it would be based on Federal standards (assuming the motor is a type covered by Federal standards). • Could use full load motor efficiency for all points or develop standard motor part-load curves. 7
Bare Pump + Motor Testing × × Manufacturer can A MOTOR Controls pair its pump data with manufacturer manufacturer motor standardized controls motor data. pump performance efficiency at full and part performance data from pump load test at rated speed Manufacturer can × B Controls measure power of PUMP MOTOR pump+motor standardized controls combo. performance 8
Bare Pump + Motor + Controls Testing Manufacturer can × × pair its pump data A MOTOR Controls with manufacturer motor data and manufacturer or default default controls default controls pump performance motor efficiency performance data from pump test credits. at rated speed B × MOTOR VFD Manufacturer can pair its pump data motor/drive performance with tested data motor+VFD data. pump performance from pump test at rated and reduced speed Manufacturer can C measure power of PUMP MOTOR Controls pump+motor+ controls combo. 9
Bare Pump/Bare Pump + Motor Equation 10
Bare Pump + Motor + Controls Equation 11
Issues to Discuss 12
Example of Metric Application Note: The example on the following slides is provided for the limited purpose of demonstrating the potential application of the PER metric. It does not represent a decision by DOE on an appropriate metric or standard level for the products to be addressed by the pumps working group. Values used to compare an example pump to the example calculated efficiency level are for illustration purposes only and should not be considered as representing recommended values. The comparison of the example PER metric to the MEI metric is provided only to demonstrate the results of the calculation, and does not represent an evaluation by DOE of the relative merits of one approach over the other. 13
How efficiency levels could be set 14
Setting Target Values 𝜃 𝑞𝑣𝑛𝑞 , BEP can be calculated the same way as in MEI, as a function of flow and specific speed. 𝜃 𝑞𝑣𝑛𝑞 at 75%, 50%, and 25% can be calculated as a percentage of 𝜃 𝑞𝑣𝑛𝑞 , BEP In the EU, pump efficiency at 75% BEP flow must be 94.7% of 𝜃 𝑞𝑣𝑛𝑞 , BEP • In the EU, pump efficiency at 75% BEP flow must be 94.7% of 𝜃 𝑞𝑣𝑛𝑞 , BEP • • Using a subset of HI data (ESFM pump, 4 pole*), DOE analyzed part-load pump efficiency as a percentage of BEP efficiency: • The results, in the form of population average values, are as follows: - At 75% BEP flow, 𝜃 𝑞𝑣𝑛𝑞 ,0.75 is 95% of 𝜃 𝑞𝑣𝑛𝑞 , BEP Efficiency as a percent of 𝜃 𝑞𝑣𝑛𝑞 , BEP was independent of flow and fairly independent of specific – speed – Agrees with EU value - At 50% BEP flow, 𝜃 𝑞𝑣𝑛𝑞 ,0.50 is 78.5% of 𝜃 𝑞𝑣𝑛𝑞 , BEP Estimated 𝜃 𝑞𝑣𝑛𝑞 , 0.50 by fitting 2 nd order polynomials to the 75%, 100%, and 110% BEP efficiency – data provided by HI. – Efficiency as a percent of 𝜃 𝑞𝑣𝑛𝑞 , BEP was independent of flow, fairly independent of specific speed, but showed a larger standard deviation than at 75% BEP (possibly due to estimating 𝜃 𝑞𝑣 𝑛𝑞 , 0.50 data) - 25% BEP flow: No data available; this flow point is omitted for this analysis *All equipment classes will be analyzed in the future 15
How efficiency levels could be set: Bare Pumps With 𝜃 𝑞𝑣𝑛𝑞 , 0.50 and 𝜃 𝑞𝑣𝑛𝑞 , 0.75 defined as (0.785 x 𝜃 𝑞𝑣𝑛𝑞 , BEP ) and (0.950 x 𝜃 𝑞𝑣𝑛𝑞 , BEP ) respectively, and using full load motor efficiency for all points, the PER Eff. Level equation can be simplified to: 1 𝑄 𝑄 𝑄 ℎ𝑧𝑒𝑠𝑏𝑣𝑚𝑗𝑑,𝐶𝐹𝑄 ℎ𝑧𝑒𝑠𝑏𝑣𝑚𝑗𝑑,0.50 ℎ𝑧𝑒𝑠𝑏𝑣𝑚𝑗𝑑,0.75 𝑄𝐹𝑆 𝐹𝑔𝑔.𝑀𝑓𝑤𝑓𝑚 = × 𝜕 0.50 + 𝜕 0.75 + 𝜕 BEP 𝜃 𝑛𝑝𝑢𝑝𝑠 0.785 × 𝜃 𝑞𝑣𝑛𝑞,𝐶𝐹𝑄 0.950 × 𝜃 𝑞𝑣𝑛𝑞,𝐶𝐹𝑄 𝜃 𝑞𝑣𝑛𝑞,𝐶𝐹𝑄 Where: 𝜃 𝑞𝑣𝑛𝑞 , BEP in this example is from the MEI surface, using flow and specific speed. If this approach is used, the actual value of 𝜃 𝑞𝑣𝑛𝑞 , BEP could be determined by the C- value or “MEI • 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 demonstration purposes only. If this approach is used for the rating metric and standard, the selection of actual values for these factors would be made based upon further analysis. 16
Example Scenario and Calculations Given the Following Theoretical Pump and Parameters • BEP Flow: 880 GPM • BEP Head: 117 ft 𝜃 BEP = 84.04% • Specific Speed: 1500 𝜃 0.75 = 80.98% • P BEP = 30.99 HP (Shaft), 26.0 HP (Hydro) 𝜃 0.50 = 71.50% • P 0.75 = 27.67 HP (Shaft), 22.4 HP (Hydro) • P 0.50 = 24.64 HP (Shaft), 17.6 HP (Hydro) 𝜃 Motor, Default = 93% • • Load Point Weight = 1/3 [even] 𝑄 0.50 𝑄 0.75 𝑄 𝐶𝐹𝑄 𝑄𝐹𝑆 𝐷𝑏𝑚𝑑𝑣𝑚𝑏𝑢𝑓𝑒 = 𝜕 0.50 + 𝜕 0.75 + 𝜕 𝐶𝐹𝑄 𝜃 𝑛𝑝𝑢𝑝𝑠 𝜃 𝑛𝑝𝑢𝑝𝑠 𝜃 𝑛𝑝𝑢𝑝𝑠 0.93 × 1 1 𝑄𝐹𝑆 𝐷𝑏𝑚𝑑𝑣𝑚𝑏𝑢𝑓𝑒 = 3 × 24.64𝐼𝑄 + 27.67𝐼𝑄 + 30.99𝐼𝑄 = 29.86 𝐼𝑄 17
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