With regard to the so called extended product approach (EPA), an appropriate methodology to qualify respectively verify these extended products has been successfully developed at the Institute for Fluid Systems of Technische Universität Darmstadt – supported by Europump – for single pump units. The EPA is a measure to meet the energy related products (ErP) and energy using products (EuP) requirements of the European Commission.

Based on the experience of this work Europump decided to expand the EPA also to booster pump units, which normally consist of multiple pumps as well as further hydraulic and electric components to ensure the specific demands of pressure boosting within buildings. A characteristic rating is needed to compare and quantify the energy efficiency of booster pump units in a standardized way. The development of a draft standard proposal for further regulation is the final objective of this work. As a result the energy efficiency index (EEI) as a normalized weighted average of the electrical input power for a booster pump unit operating at different duty points at part load is introduced. A standardized load-time profile and a pressure control curve are defined in order to compare lifetime efficiency and part load behaviour. The EEI will be determined using both an experimental and semi-analytical approach.

Main task of the experimental work is the development of a measurement procedure for the EEI determination, which can be summarized as a realization of sensitivity studies in order to deduce all major effects on the EEI for a subsequent standard elaboration. This includes the definition of needed accuracy and acceptable tolerances of flow-adjustment and used sensors as well as the examination of parameters affecting the power consumption of the booster pump unit. Besides, steady state operation for each duty point has to be guaranteed. A method for non-adjustable duty points within the given constraints has to be implemented which is attended by the exertion of penalties in EEI for overshooting. The tasks of the Institute for Fluid Systems of Technische Universität Darmstadt are the development and neutral assessment of all required measurement procedures.

Besides the experimental work, a semi-analytical approach is developed which allows calculating the electrical input power and thus the EEI with reduced experimental effort in future. The resulting semi-analytical model (SAM) is based on empirical data for frequency converters, motors and pumps as well as analytical laws describing the physics of booster system behaviour. A further advantage of SAM is the possibility of systematic determination of EEI values for booster units consisting of components delivered by different manufacturers.