Assessing the Energy Efficiency of Pumps and Pump Units

Background and Methodology

em. Dr.-Ing Bernd Stoffel

• Publisher: Elsevier
• Year: 2015
• Print ISBN: 9780081005972
• eBook ISBN: 9780081006658
• Topic: Business
• Subtopic: Investments & Securities
• Index: Business

Assessing the Energy Efficiency of Pumps and Pump Units, developed in cooperation with Europump, is the first book available providing the background, methodology, and assessment tools for understanding and calculating energy efficiency for pumps and extended products (pumps+motors+drives). Responding to new EU requirements for pump efficiency, and US DOE exploratory work in setting pump energy efficiency guidelines, this book provides explanation, derivation, and illustration of PA and EPA methods for assessing energy efficiency. It surveys legislation related to pump energy efficiencies, provides background on pump and motor efficiencies, and describes the concept of Energy Efficiency Index (EEI) for circulators and single and multi-pump systems.- The first book to cover Europump- sponsored research on energy efficiency in pumps, including coverage of new EU guidelines implemented in January 2015- Discusses Product Approach (PA) and Extended Product Approach (EPA) to assessing energy efficiency- Derives and explains the Minimum Efficiency Index (MEI)

Chapter 1

The Role of Pumps for Energy Consumption and Energy Saving

The yearly generation of electric energy in various types of power plants and the “energy mix” determine the yearly CO₂ emission. Distributions of the consumption of electric energy illustrate the significant contribution of electric motors in general and in particular that of electric motor driven pumps. The consumption of electric energy by the use of rotodynamic pumps (that form the objects of the book) depends not only on the efficiency of the pumps and their drives but also on characteristics of the hydraulic installation, which is supplied with fluid energy, and on the mode of operation. There exist a considerable energy-saving potential for pumping systems and technical measures to realize this potential. Legislative measures promote the practical realization and lead to benefits for the environment and consequences for the pump market.

Keywords

Electric energy generation; electric energy consumption; electric motors; rotodynamic pumps; efficiency; hydraulic installation; energy-saving potential; technical measures; legislative measures; benefits

1.1 Generation and Consumption of Electric Energy

The utilization of electric energy for many various purposes is a characteristic aspect of modern technics and human life.

1.1.1 Generation of Electric Energy

Electric energy is generated by converting primary energy sources. A significant part of these primary sources consists of the fossil combustibles black coal, brown coal, mineral oil, and natural gas. These combustibles are converted into electric energy in conventional power plants. A second part of primary sources consists of radioactive materials, which are used in nuclear power plants to generate electric energy by nuclear fission. A third and increasing part of primary sources is renewable (water power, wind, solar radiation, biomass) and is converted in different technical facilities (e.g., water power plants, wind turbines, solar energy plants, biomass power plants) into electric energy.

In the European Union (EU), the total generation of electric energy was 3295 TWh in 2012 [1].

According to Ref. [2], the following mix of electric energy generation in the EU existed in 2007 and is expected for 2020, respectively (Table 1.1):

Table 1.1

Mix of Electric Energy Generation in Europe

	2007	2020
By fossil-fueled power plants	56.0%	46.5%
By nuclear power plants	28.0%	21.0%
From renewable sources	16.0%	32.5%

One aspect of both the fossil-fueled and the nuclear power plants is their contribution to the irreversible consumption of limited reserves of primary energy sources. This is a first motivation, to reduce electric energy generation by saving electric energy.

In the case of nuclear power plants, the risk of nuclear accidents and the issue of nuclear waste having possible effects on the environment and on humans are motivations to reduce their number worldwide.

Concerning the fossil-fueled power plants, a severe aspect is their emission of CO₂, which is classified as a “greenhouse gas” and is responsible for medium- and long-term climate change. Therefore, international commitments, especially in the EU and in its member countries, aim for the general reduction of CO₂ emissions by certain amounts and by certain dates. The major EU policy package, called the climate and energy package, which was adopted and became a binding legislation in 2009, includes as one of the targets for 2020 the reduction in EU greenhouse gas emissions of at least 20% below 1990 levels.

This leads—besides other goals, such as to reduce the CO₂ emission of traffic and heating of buildings—to the requirement of reducing CO₂ emissions that result from the generation of electric energy. Depending on the fossil fuels used as primary sources in the different types of fossil-fueled power plants, on their plant efficiency, and on the mix of the electric energy generated by them, the emission of CO₂ caused by generating electric energy in fossil-fueled power plants ranges from 630 to 980 g/kWh, according to Ref. [3]. This means that the mass of CO₂ emitted from fossil-fueled power plants is approximately proportional to the electric energy generated by them. In combination with the numbers given above, this results in an emission of approximately (2–3)·10⁹ t of CO₂ by generation of electric energy in fossil-fueled power plants within the EU in 2012.

The electric energy generated in power plants and other generation facilities of different types and located at various sites is fed into common electric supply networks and transmitted to each end user. It is supplied to the end users as three-phase alternating current (AC) of constant voltage and frequency. In the EU, the latter is generally 50 Hz for residential, public, and industrial applications.

1.1.2 Consumption of Electric Energy

The total consumption of electric energy can be divided into several categories, such as driving (electric motors), lighting, heating, communication, information,...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• About the Author
• Preface by the President of Europump
• Acknowledgments
• Abbreviations
• List of Abbreviated Subscripts
• List of Symbols
• Introduction
• Chapter 1. The Role of Pumps for Energy Consumption and Energy Saving
• Chapter 2. Standardization and Legislation Regarding the Energy Efficiency of Pump Units
• Chapter 3. Overview on Europump Approaches on Assessment of Energy Efficiency
• Chapter 4. Physical and Technical Background of the Efficiency of Pumps
• Chapter 5. Physical and Technical Background of the Electrical Power Input of Pump Units
• Chapter 6. The Role of Manufacturing Tolerances
• Chapter 7. The Concept of the Minimum Efficiency Index (MEI) for Pumps
• Chapter 8. The Concept of the Energy Efficiency Index (EEI) for Circulators and Pump Units
• References
• Index