BS EN 17038‑1:2019 pdf download.Pumps – Methods of qualification and verification of the Energy Efficiency Index for rotodynamic pump units Part 1: General requirements and procedures for testing and calculation of Energy Efficiency Index (EEI).
4.2 Weighted-average value of the electric power input The quantification of energy efficiency of pump units should be based on the weighted average of electrical power input P 1, avg . The weighting factor when averaging the electrical power input P 1 is the fraction of operating time at the respective flow rate. Generally, for any application there is a continuous function describing the dependency of (differential) time fraction dt/t tot on the relative flow rate Q/Q 100 % where t tot is the total operating time and Q 100 % is defined in the specific parts of this standard. For the assessment of the energy efficiency of pump units, common and standardized “flow-time profiles” are needed as basis for indicating their energy efficiency. The flow-time profile is defined for each pump type in other parts of this standard.
In order to simplify further the determination of a value which characterizes the energy efficiency of pump units, in this document the different flow-time profiles are described by a limited number of points, not by a continuous curve or function. These discrete points are pairs of values of Q/Q 100 % and Δt/t tot . These values define the discretised flow-time profiles. They are given as reference flow-time profiles in the specific parts of this standard. (In this case, Δt is a finite fraction of operating time and Q/Q 100 % is the average value of relative flow rate demanded within this time fraction.) NOTE 1 The reference flow-time profiles defined in this document for variable flow operation reflect the typical ranges and variations of demanded flow rate in these types of applications and are based on experimental field studies, see [1], [2].
But as for the flow-time profiles, common and standardized correlations H/H 100 % = f (Q/Q 100 % ) are needed as basis for indicating and comparing the energy efficiency of pump units placed on the market and/or put into service as extended products. These standardized correlations H/H 100 % = f (Q/Q 100 % ) are called reference pressure control curves in this document and are defined in subsequent parts of this standard. For calculating P 1, avg in the case of variable speed operation, the electric power input P 1 shall be determined at the relative flow rate values Q/Q 100 % of the relevant reference load-flow profile and for the corresponding rotational speed n. NOTE 2 Especially at low values of Q/Q 100 % the electric power input P 1 is considerably higher for pump units operated at constant motor stator frequency than for speed controlled pump units. This holds true independently of the actual pressure control curve.
4.3 The reference electric power input P 1, ref For assessing the energy efficiency of pump units within the scope of this document, a non-dimensional value is needed which directly reflects the energy efficiency of pump units. The numerical magnitude of this value shall be independent of parameters which influence the unit component’s efficiency such as, for example, their geometrical size and nominal power. For this purpose, the actual electrical power input P 1, avg averaged according to Formula (1) is divided by an appropriate reference value P 1, ref . This reference value shall: — have a physical basis; — consider relevant influences on the electrical power input of pump units; — be independent from the efficiency related quality of individual components of the pump unit. The chosen definitions of P 1, ref which fulfil these requirements are given in other parts of this standard.BS EN 17038‑1 pdf download.