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Hessian Ministry of Economics, Transport, Urban and Regional Development www.hessen-umwelttech.de

A Practical Guide to Energy EfďŹ ciency in Production Processes

Hessen Hessen

Umwelttech Umwelttech


A Practical Guide to Energy EfďŹ ciency in Production Processes

Volume 8 of the Publication Series of the Aktionslinie Hessen-Umwelttech


IMPRINT

A Practical Guide to Energy Efficiency in Production Processes

A Title in the Publication Series of the Aktionslinie Hessen-Umwelttech of the Hessian Ministry of Economics, Transport, Urban and Regional Development

Publisher:

HA Hessen Agentur GmbH Dr. Carsten Ott Abraham-Lincoln-Straße 38-42 65189 Wiesbaden Tel: + 49 611 774-8350 Fax: + 49 611 774-8620 www.hessen-umwelttech.de

Written by:

Prof. Dr.-Ing. Jens Hesselbach, Department of Environmentally Sustainable Products and Processes, University of Kassel Dr.-Ing. Mark Junge, Limón GmbH Dipl.-Ing. Bastian Lang, Department of Environmentally Sustainable Products and Processes, University of Kassel Dipl.-Wirtsch.-Ing. Sabine Mirciov, Limón GmbH Dr.-Ing. Clemens Mostert, deENet e.V. Dipl.-Ing.M.Sc. Alexander Schlüter, Department of Environmentally Sustainable Products and Processes, University of Kassel Dipl.-Ing. Hans-Georg Weishaar, deENet e.V.

Editorial Team:

Maria Rieping (Hessian Ministry of Economics, Transport, Urban and Regional Development) Dr. Carsten Ott, Dagmar Dittrich (HA Hessen Agentur GmbH, Aktionslinie Hessen-Umwelttech)

© Hessisches Ministerium für Wirtschaft, Verkehr und Landesentwicklung Kaiser-Friedrich-Ring 75 65185 Wiesbaden www.wirtschaft.hessen.de

Duplication and reprinting – in whole or in part – subject to prior written consent.

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April 2011

The Publisher will assume no responsibility for the correctness or accuracy of the information or for observance of the private rights of third parties.


CONTENTS

1. INTRODUCTION

3

1.1

How to use this Guide – and for whom it is intended

3

1.2

The situation at present – why energy efficiency?

3

1.3

The Model Project

4

2. WHAT IS ENERGY EFFICIENCY AND HOW CAN IT BE ESTABLISHED IN COMPANIES?

5

2.1

Definitions

5

2.2

Energy efficiency potentials

7

2.3

Preparing the ground

8

3. METHODOLOGY AND TOOLBOX

10

3.1

Methodology | standardized procedures

10

3.2

Tools | analysis

13

3.3

Tools | simulation

17

4. PRACTICAL APPROACHES AND RECOMMENDATIONS FOR ACTION

22

4.1

Generation of electricity and heat

22

4.2

Uses for cooling | cooling production

23

4.3

Compressed air

23

4.4

Steam

24

4.5

Heat recovery (HR)

25

4.6

Thermal insulation

25

4.7

Drying technology

26

4.8

Indoor climate

27

4.9

Motors | drives

28

4.10

Pumps

28

4.11

Ventilators

29

4.12

Lighting

29

5. RESULTS OF THE MODEL PROJECT

30

5.1

Lighting

30

5.2

Pump technology

32

5.3

Granule drying

34

5.4

Cooling

35

5.5

Heating | ventilation

36

5.6

Interlinked heating system

38

5.7

Trigeneration

39

5.8

Simulation supported energy efficiency analysis

41

6. APPENDIX

46

6.1

Authors | project partners

46

6.2

HessenModellProjekte – Funding for applied research and development projects

47

Aktionslinie Hessen-Umwelttech and Hessen-PIUS

48

6.3


3. METHODOLOGY AND TOOLBOX


Foreword

Efficient management of energy is essential if our economy is to grow sustainably. The discussions about the safeness of nuclear power are getting more serious, fossil fuels are becoming scarcer and more expensive, and at the same time the need to protect our environment and the climate makes it a matter of urgent necessity to use energy responsibly and efficiently. Companies which take account of this in their strategic planning will cut their operating costs, since energy saving measures usually pay for themselves in a few months or years. Quite apart from this, they help to set the course towards a future economy which is energy efficient, and for this very reason competitive. There is a great deal of potential available, especially in manufacturing companies, as will be seen from the present Guide issued by the Aktionslinie Hessen-Umwelttech. This Guide is based on the model project “Energy Efficiency and Large-scale Consumers” funded by the Hessian Ministry of Economics and the EU. In this project, various energy saving measures were systematically analysed in two exemplary companies, attention being paid to feedback effects. In this way it was possible to work out ideal sets of measures for the companies concerned. The recommendations for action and the results are addressed primarily to manufacturers with relatively high energy consumption – among which are to be found many small and medium-sized firms. Many of the measures, e.g. in the areas of indoor climate or lighting, will also be of interest for less energy intensive sectors. In addition to suggestions for various individual measures, the publication also gives guidance for regular, standardized analyses of energy saving potentials and shows how important it is to consider the different measures within a wider, interlinked context. I hope this brochure will be a source of interesting ideas and that it will give you valuable impulses for your own company.

Dieter Posch Hessian Minister of Economics, Transport, Urban and Regional Development

1


2


1. INTRODUCTION

1. Introduction 1.1 How to use this Guide – and for whom it is intended This Guide is intended primarily for producing companies in energy intensive sectors (large-scale consumers). Companies in this category often possess considerable potentials for cutting their energy demands. However, a good deal of the material in this Guide is also applicable to less energy intensive companies. The groups addressed are mainly engaged in the areas of energy management, facility management, production management, maintenance, process management and controlling. The aim is to set out the general procedure for energy

efficiency projects, to give examples and make suggestions how to develop suitable measures, and to point out success factors. The spectrum ranges from simple to complex structures. In the case of simple structures, the do-ityourself principle is often sufficient. In more complex situations, decisions on the energy saving measures to be taken will usually call for support from a provider of energy services. In this context, simulations are a good method of analysing the interactions of single measures and arriving at an integrated energy concept.

1.2 The situation at present – why energy efficiency? The reduction of greenhouse gas emissions is one of the most important tasks confronting our society – and not only since the presentation of the IPCC Report on Climate Change. This task involves not only the changeover to renewable energies for our final energy production but also a sharp increase in energy productivity. Energy efficiency – or energy productivity – is an area which provides a very large potential for reducing greenhouse gases and thus for achieving the goals set by the German government. All economic activity is caught between the conflicting demands of energy generation and climate (Figure 1). Improvements in energy efficiency lead to lower energy costs and thus to increases in productivity. They also make companies less dependent on energy price developments and the difficulties of calculating them – which, in view of the limited supplies of fossil fuels, is in itself an important economic advantage.

Energy efficiency = reduction of greenhouse gases = profitability

The most characteristic feature of energy efficiency measures in industry is that they involve an enormous number of individual measures. As a result, the overall view tends to move out of focus. However, a soundly based analysis of energy and material flows for a production process, a production site or a company will show that many of these flows interact. For this reason, individual measures may have unfavourable effects elsewhere. The insulation of machines, for example, may lead to higher heating costs, since the heat they give off is no longer available for warming the production hall. The high complexity of large-scale consumers makes it particularly worthwhile to analyse these interactions in order to achieve high energy efficiency. This can be done only by a systemic analysis.

3


3. INTRODUCTION 1. METHODOLOGY AND TOOLBOX

Figure 1: Economic activity between the conflicting demands of energy generation and climate

Climate | Air quality

Generation of energy

Storage

Thermal

Global

Local

Factory Electrical

Regional Building

Processes

Logistics

FUNDING OF THE

1.3 The Model Project

MODEL PROJECT

Concrete energy saving potentials available to industrial large-scale consumers and the methods and measures opening up the most favourable prospects for economic success were investigated in specific examples within the framework of the Hessian model project “Energy Efficiency for Large-Scale Consumers”. The project was funded by the Hessian Ministry of Economics and the EU and implemented by the Department of Environmentally Sustainable Products and Processes” at the University of Kassel (upp), Limón GmbH, and Kompetenznetzwerk Dezentrale Energietechnologien (deENet).

This project was funded by the State of Hessen, co-financed by the European Union (European Regional Development Fund – ERDF)

Hessian Ministry of Economics, Transport, Urban and Regional Development

EUROPEAN UNION Investing in your future – European Regional Development Fund

4

The aim was to analyse and select the ideal measures by means of a simulated linking of the entire range of measures taken to improve energy efficiency. The database used for setting up the simulation models was provided by two companies which had been taken as examples – a brickworks and a plastic injection moulding company. Once all of the relevant material and energy flows within the companies had been recorded and documented, measures were devised for reducing energy demands. A dynamic simulation model was developed, on the basis of which it became possible to draw up a holistic evaluation. This was the only way to record the entire spectrum of interactions and test the various measures. The analysis of the dynamic materials and energy flows using the simulation model yielded mutually coordinated energy efficiency measures. The results of the project are set out in detail in Chapter 5.


2. WHAT IS ENERGY EFFICIENCY…?

2. What is energy efficiency and how can it be established in companies? 2.1 Definitions 1. What is a large-scale consumer? For the purposes of this guide, large-scale consumers are defined as companies in which energy1 costs make up more than 3 percent of the production costs. This applies also for many small and medium-sized companies.

Highly energy-intensive sectors are concerned here. These include: » the food industry » the paper industry » the manufacturing of chemical products » rubber and plastic goods production » the glass industry » ceramic, cement and brick production » metal production and processing The relative number of companies which are large-scale consumers in the sense of this definition is constantly growing. The reason for this is the disproportional increase in the prices for energy, as evidenced in the graph below.

Figure 2:

240 %

Producer and import index

Energy cost development

220 %

for selected fuels

200 %

Source: Federal

180 %

Statistical Office

160 % 140 % 120 % 100 %

Import price index oil

80 %

Import price index gas

60 % 2000

2001

2002

2003

2004

1 Energy = electricity, gas, oil, where applicable heat/cooling

2005

2006

2007

2008

Producer price index electricity for industrial plants

5


2. WHAT IS ENERGY EFFICIENCY AND…

This means that energy costs are exerting an ever greater influence on production costs. Since energy cannot be replaced altogether, only one action strategy remains: to optimize its use or to make it more efficient. 2. What is energy efficiency? The word efficiency comes from the Latin “efficientia”, meaning effectiveness or activity. In terms of energy, efficiency is understood as the “ratio of energy intake to energy benefit within a system”. In other words, the greater the benefit obtained from input energy, the higher the energy efficiency. In the technical sense, the term efficiency is used principally to mean energy conversion efficiency.

Electricity: 200 kWh

Waste Heat: 20 kWh

If the thermal and mechanical energy in the example shown in Figure 3 is fully utilized, the efficiency of the energy input will be 100 percent. All that is needed to operate a conveyor belt is mechanical energy – the thermal portion is merely the waste heat from the motor which is given off unused into the surrounding area, with the result that the efficiency/energy conversion efficiency here is only

Figure 3: Example of energy efficiency, waste heat v. mechanical work

Mechanical work: 180 kWh

= 180   kWh = 90 % 200 kWh If arrangements are made to recover this heat for the purpose of space heating the energy benefit will be higher. The purpose of energy efficiency measures is to achieve the desired benefit with as little energy input as possible. This has a great economic effect, particularly in connection with frequently repeated or continuous processes, because energy which is not used does not have to be paid for. However, the costs for implementing such measures must also be taken into account in profitability studies.

6


…HOW CAN ENERGY EFFICIENCY BE ESTABLISHED IN COMPANIES?

2.2 Energy efficiency potentials With its electricity, gas and oil demands, the producing industry accounts for a large share of Germany’s total energy consumption and hence of its greenhouse gas emissions. Most of the industrially used energy is taken up as a rule by machines and plants, and also by the necessary process heat. On top of this comes the cooling technology required for dissipating excess heat, together with heating, ventilation and lighting inside the building. In 2006, electricity consumption in German industry came to 253 TWh (cf. Figure 4). This amounts to more than 47 percent of overall consumption.

Industry 253 TWh 144 TWh

Other (transport, public facilities, agriculture and trade)

26,7 % 46,9 %

26,4 %

142 TWh

Intelligent handling of energy is thus a major economic factor and will make a substantial contribution towards achieving sustainable development. This goal was defined in the coalition agreement: by 2020 the German government aims to achieve a doubling of energy productivity – primary energy consumption in relation to GNP – as compared with 1990 (cf. Figure 5).

Figure 4: Electricity consumption in Germany, 20062

200 % Energy productivity compared with 1990

In view of the time periods needed for implementing new energy systems, decisions must be taken now as to how the necessary power demands can be met – with due attention to the question of sustainability. A key role must be played in future not only by increased use of renewable energies but also by energy efficiency and decentralized energy supplies. These are the quickest, the most important and, in the long term, cheapest options for the protection of both climate and resources.

Households

150 %

100 %

50 % planned 0% 1990

1995

2000

2005

As a result of the present price situation, efficient handling of electricity, though also of heat, has never paid for itself so quickly as at present. The payback period for investments in energy efficiency technologies today are on average 20 percent shorter that only three years ago. In view of the rapid increases in energy prices, companies are keen to seize the opportunities for reducing their energy consumption.

2 VDEW: Electricity statistics, 2007 3 German Federal Statistical Office and the UBA [Federal Environmental Agency]

2010

2015

2020

Figure 5: National sustainability strategy: doubling of energy productivity by 20203

7


2. WHAT IS ENERGY EFFICIENCY AND…

Percentages of companies interviewed 0%

5%

10 %

15 %

20 %

25 %

30 %

35 %

Analysis of energy saving potentials Implementation of measures, controlling Development of appropriate energy efficiency measures

Survey of German companies on the subject of energy efficiency (2005)

Financing of investments

Figure 6:

Other

Remaining percentages – no information

Priority themes for energy efficiency in German companies4

As shown by a survey conducted on behalf of the Deutsche EnergieAgentur (dena) (cf. Figure 6), there are still considerable gaps in our knowledge, particularly as concerns the analysis of energy saving potentials which could help to cut costs and raise profits. There is also a need for advisory services to help with the development of appropriate measures for enhancing energy efficiency in practice. Since energy prices will probably continue to rise over the foreseeable future, incompany optimization of energy will pay off in the long term.

8

2.3 Preparing the ground The most important step a company must take is to realize not only that energy costs form a relevant share of the production costs but also that their reduction will create an important competitive advantage. Energy costs should therefore be traced back to their causes and evaluated within the framework of cost-benefit accounting. This is the only way to achieve a longterm cost reduction. To do this in practice, an energy management system will have to be implemented in order to identify and analyse the energy flows. In addition, a responsible must be appointed and given a suitable position in the company organization. The extent of the work involved here will depend on the size of the company – in small firms the tasks involved can be combined with other areas of responsibility. An example of an organizational structure is shown in the graph below:

4 dena: Company surveys on the theme of energy efficiency, 2005, Question: In which of the following areas do you see the greatest need for support in your company with regard to energy efficiency?


…HOW CAN ENERGY EFFICIENCY BE ESTABLISHED IN COMPANIES?

The position of the person responsible for energy issues includes the following tasks: » organization and monitoring of energy data collection » performance of energy audits » support for service providers (e.g. data acquisition, selection of measures) » evaluation and selection of energy efficiency measures » definition of energy efficiency targets » in-house communication on the theme of energy » monitoring and support during implementation of the measures

Company or Division Management

Energy Manager (Central documentation and responsibility for implementation of measures) Information

Measures

Information

Procurement/Controlling

Technical Staff

(Energy accounting +

(Production engineering +

contracts)

maintenance)

Figure 7: Organizational structure of Energy Management

While the energy efficiency projects are in progress, it would be worthwhile setting up a project team composed of controlling specialists and technical staff. The decision as to what can be done by the company itself and what should be left to a service provider will depend on the extent to which the company staff possesses the necessary know-how and whether sufficient time is available. General measures (such as lighting) can often be carried out by the company itself with the aid of check lists. For more complex tasks it is advisable to take advantage of external know-how.

9


3. METHODOLOGY AND TOOLBOX

3. Methodology and toolbox 3.1 Methodology | standardized procedures HOW SHOULD THE BALANCE SCOPE BE DEFINED? If the balance scope is too large, it will not be possible to assign the energy and material flows to their separate origins. If the boundaries are too constrictive, or if many small balance scopes are defined, the analysis will involve excessive time and costs.

To enable potentials to be realized within the framework of an energy efficiency project, a standardized procedure will have to be used. A helpful instrument here is VDI Guideline 3922, “Energy Consulting for Industry and Business”. A characteristic feature of this procedure (Figure 8) is the iterative process. The purpose behind this is to check energy use at regular intervals and where necessary to carry out changes or renewals.

Recording the current state Production data Presentation and evaluation of the current state

Technical data Consumption accounting

Implementation & result checking

Energy efficiency proposals

Evaluation of the measures selected

Development of an overall concept

Figure 8: Procedure for implementation of energy efficiency measures

10

The first step towards identifying energy efficiency potentials and effecting optimization within the company is to record the current state. This will make it necessary to collect all

relevant data on energy supplies and energy consumption (e.g. technical documentation on energy consumers, energy infrastructure and energy recovery) in order to provide as sound a basis as possible for a description of the current state. To create this basis, the energy consumption data must be assigned as carefully as possible to their separate origins. For this purpose, a balance scope will have to be defined for the individual origins (energy consumers) and suitable measuring devices installed if required. It will also be necessary to classify the data by energy carrier (e.g. electricity, heat) and category (e.g. lighting, ventilation). The balance scopes can cover, for example, machines, cost centres or production areas. Additional measurements may have to be taken if there are not enough data for a sufficiently exact description. To this end, the measurements should be made as accurately and comprehensively as necessary in order to avoid costly and timeconsuming work. The extent of the measurements will be governed by the particular framework conditions (e.g. representative time periods, dependence on other parameters).


3. METHODOLOGY AND TOOLBOX

The measuring work can be reduced with the aid of model calculations, verified by exemplary measurements, which can then be used for forecasting under other sets of conditions. Once all the data have been collected, the current state can be described and evaluated. It will be worthwhile at the beginning to make a list of the balance scopes (energy consumers), classified according to energy demand and the relevant energy media. With the aid of this classification, the company’s heaviest energy consumers can be sorted out for consideration. The individual balance scope is evaluated by creating key figures and performing comparisons. The comparisons can be made in various ways, e.g. either with other divisions or locations within the company, or with external key figures, e.g. sectoral figures or best practice values. Such comparisons serve as a guide for specific improvements in the company’s own efficiency. The description of the heaviest users and the evaluation of the key figures serve as a basis for defining areas with energy saving potential. The next step is to work out proposals for increasing energy efficiency in the areas with energy saving potential. Examples of various such areas are given in Chapter 4. When devising measures, it is important to take into account the approaches set out in Figure 9.

Avoidance of energy use, for example in the case of cleaning machines, can be taken to mean changing over to a cleaning agent which is effective at ambient temperatures. Reduction of energy demand, on the other hand, can be achieved by using, for example, a mechanical drying process (spin-drying) instead of heat drying. Reduction of transformation losses is concerned with the reduction of losses in the upstream stages of final energy production (e.g. heating by gas instead of electricity). In addition, energy demand can be lowered by adapting the temperature level in heating or cooling processes (e.g. raising the temperature of cooling water to allow use of free cooling instead of a compression chiller). Another means of increasing energy conversion efficiency is to use more efficient motors and thus ensure more effective use of the energy input. One way of interlinking energy flows is to recover heat from waste air.

(1) Avoidance of energy use (2) Reducing of energy demand (3) Reduction of transformation losses (4) Adaptation of temperature levels (5) Increasing energy conversion efficiency (6) Interlinking and integration of energy flows

Figure 9: Procedure for developing energy saving measures

11


3. METHODOLOGY AND TOOLBOX

The order in which these various elements are put into practice is not imperative. However, after the first steps have been taken, it may turn out either that the later ones are no longer necessary – or that they can only then be put into practice at all. For example, there will be no need to examine ways of providing heat more efficiently if a process has been optimized in such a way that it runs at ambient temperature, thus no longer requiring any heat. On the other hand, it is imperative to observe the system in its entirety. In certain cases, particular measures may interact and have an adverse effect on the final result. The idea behind Figure 10 is to show that individual measures can have effects on different areas of action. For this reason, it is not possible to lay down an absolute order in which the procedure should be carried out.

(2) Reduction

(1) Avoidance

Figure 10: Interactions between

(6) Interlinking & integration

(3) Transformation losses

(4) Temperature level

(5) Energy conversion efficiency

the individual areas of action

The next step is to work out an overall concept on the basis of the individual suggestions discussed earlier. Although efficient use of energy remains in the foreground, it is also important to make allowance for economic effects and the impact of the concept on technology and product quality.

12

Moreover, several alternatives should be worked out and compared with one another in the manner of a scenario analysis. This can be done particularly effectively with computeraided simulation instruments. Relevant decision-making criteria are provided here by key business figures and the energy saving potential. The fixed and variable costs incurred and the anticipated energy and cost savings must be defined in the profitability study. A distinction can be drawn between static and dynamic procedures. Static procedures are characterized by a high degree of transparency and are easy to follow. Dynamic procedures are more accurate, especially over longer periods of time, but they involve much more work. Decisions should also be supported by sensitivity analyses5, since these enable risks to be estimated more reliably. Other criteria in addition to the profitability evaluation should also be taken into consideration, though the priorities here often differ from one company to another. Some examples of such criteria are security of supply,

5 The sensitivity analysis tests the influence of factors or parameters (separately or jointly) on particular result values.


3. METHODOLOGY AND TOOLBOX

the emission balance, anticipated new regulations or funding programmes, regional or sector-specific developments, and corporate image. Implementation and result checking should be carried out under the supervision of the advisor. If the desired results are to be obtained, special care must be taken to ensure that the measures are implemented correctly. Continuous recording and maintenance of the energy-related data will make it possible to assess at regular intervals how far the goals have been achieved.

CONSTANT ITERATION

The process described above should not be carried out only once, but should be repeated regularly. For one thing, production is subject to constant change, and for another, the measures effected provide the basis for new fields of action. For this reason the implementation of efficiency measures – as already shown in Figure 8 – should take the form of cyclic repetition.

3.2 Tools | analysis When analysing potentials for improving energy efficiency it is essential to have a clearly defined procedure. For this purpose use can be made of standardized tools with the aid of which a rapid, objective and effective analysis can be performed. A selection of such tools will be given below. Collecting data with the aid of questionnaires Important information for assessing the energy situation and creating initial key figures can be obtained by means of a simple questionnaire. This

framework will make it possible to collect data both on energy use and on energy provision for all energy media. Here are some of the data for which the questionnaire can be used: » number of employees » annual turnover » plant area » shift work system » production hours » products » production processes and machines » energy consumption values (electricity, gas, oil) » technical data on heating or cooling plants

13


3. METHODOLOGY AND TOOLBOX

The company keeps the data in various forms (e.g. energy accounts, factory data capture, operating hours counters, construction plans, business reports). Missing data needed for further analysis can be obtained from the energy supplier, substantiated and, where necessary, checked by measurements: » energy consumers (machines, compressors, pumps, etc.) and energy procurement » energy distribution » energy provision (electricity, heat, cooling, compressed air) » building and building services engineering » measures implemented Utilization of existing in-house databases Many industrial companies have set up environmental management systems. This has been motivated by, and modelled on, the DIN ISO 14001 or EMAS6 standards for the certification of successful environmental management based on continual improvement. For the generation of key environmental figures or the evaluation of environmental performance it is necessary to have recourse to in-house data sets on use of resources, energy consumption, and water and waste management.

Energy monitoring Monitoring, especially of energyrelevant processes and machines, makes it possible to collect detailed, time-resolved data. These energy data for individual processes and machines make it easier to achieve more effective identification of efficiency potentials and to calculate savings. Care must be taken during the course of monitoring to ensure that specific data are collected and set in relation to production output. It is not enough simply to collect data and present consumption graphs, since production output is the principal driver of energy demands. Only if production output is taken into account will it be possible to establish comparisons. Monitoring also serves as an early warning system, e.g. for detecting faults in processes and for tracing leaks. Key figures The best way to achieve comparability of energy consumption data is to establish key figures. Various comparisons could be made, for example: » data over various time periods » data for different production sites » comparison with “best practice” examples (companies, or machines and plants) » comparison with the industry average » comparison with physical models (e.g. calculation of the energy consumption for a particular process using basic thermodynamic formulae) Decisive for a comparison are also the key figures chosen and the basis on which they are established. Examples of typical key figures are: » specific energy demand, e.g. per product (kWh/piece, kWh/kg), per area (kWh/m²) and per employee (kWh/empl.) » ratio of energy costs to turnover or to production costs

14

6 EMAS is the abbreviation for Eco-Management and Audit Scheme, also known as the EU Eco Audit.


3. METHODOLOGY AND TOOLBOX

110 °C

110 °C

100 °C

100 °C

90 °C

90 °C

80 °C

80 °C Temperature

Temperature

Pinch analysis The pinch analysis is used to identify potentials for the integration of heat and cooling. The aim is, by means of energy integration, to optimize the inputs from all energy sources (e.g. steam, cooling water) with a view to minimizing energy demands and costs. Heat sources (hot streams) and heat sinks (cold streams) are linked either by heat exchangers or by trigeneration. Process streams are plotted on a temperature-energy flow chart (Figure 11).

70 °C 60 °C 50 °C 40 °C

PINCH Thermodynamic bottleneck

70 °C 60 °C 50 °C 40 °C

30 °C

Cooling 30 °C requirement

20 °C

20 °C

10 °C

Heat recovery range

Heating requirement

10 °C 0

5

10

15

20

25

30

35

40

45

MJ

0

5

10

15

20

25

30

35

40

Energy

The composite curves for the heating and cooling energy flows represent the cumulative cooling and heating requirement at the temperature level in question. The ranges in which the curves do not overlap show the minimum necessary cooling or heating requirement.

Different evaluation methods After the information has been collected, it should be presented as clearly as possible. Here are some of the methods: » Sankey diagrams » bar charts » pie charts » hit lists » ABC analyses

45

MJ Energy

Figure 11: Pinch analysis graph7

It is advisable to process the data and show them in graphs. Each type of representation highlights different information. A selection of typical graph forms is shown in the following Figures:

7 Weiterentwicklung einer Optimierungsmethode zur Integration von Solarwärme in gewerblichen und industriellen Produktionsprozessen [Further development of an optimization method for the integration of solar heat in industrial production processes]. H. Schnitzer, CH. Brunner; 2006.

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3. METHODOLOGY AND TOOLBOX

Figure 12: Energy consumer C: 7 kW/h

Example of a

Energy consumer A: 10 kW/h

Sankey diagram (left) Energy consumer A: 10 kWh Energy consumer B: 15 kWh

Total consumption

Energy consumer C: 7 kWh

Figure 13: Example of a

Energy consumer B: 15 kWh

pie chart (right)

Table 1: Hit list in order of energy demand

Sequence

Energy consumer

Energy demand

1

B

15 kWh

2

A

10 kWh

3

C

7 kWh

With the aid of the graphs shown above it is possible to clearly highlight various information items. » How great are the individual input and output streams (e.g. emissions, energy demand? » How great are the individual input and output streams in comparison with others? » Where are the input and output streams too great? » Which input and output streams are the principal energy consumers?

The aim of these graphs is to present the result in a way which can be readily understood by all persons concerned. It often happens that potentials become visible only when they have been presented in graphic form. It is important that decision-makers should be informed as efficiently as possible. They need the material to be demonstrated as vividly as possible, since very often they do not have sufficient time to study the subject in greater depth.

16


3. METHODOLOGY AND TOOLBOX

This is why simple static calculation methods and rules of thumb are not sufficient for assessing energy efficiency measures. They can provide nothing more than indications for a suitable choice and hence for a more precise detailed analysis. “Simulation is the Replication of a System with its dynamic Processes is a Model that can be used for Experiments in order to reach Conclusions which can be transferred into Reality.” 8

3.3 Tools | simulation The tasks involved in the development of energy efficiency measures for large-scale consumers are often highly complex. They result from a variety of different process or quality requirements. Because of the direct interdependence between energy demand and production, any changes in the production parameters will affect the energy flow. Influential factors here are not only the overall production volume, e.g. the type of the items produced, but also the production sequence and the machines used. To achieve energy savings by efficiency measures, the first step will be to collect data on production-related energy demands. The second step will be to identify potentials, which will involve an analysis of the influence of the various measures on one another and also on the production environment.

8 VDI 3633, 2000, p. 2

In the meantime simulation has prooved its worth as an instrument for analysing complex tasks. As a general rule, simulations are used particularly when » no comparable applications exist or new areas are being explored; » the complexity is too great for the use of analytical or mathematical methods; » experiments in the real system are too costly, too dangerous, too elaborate, too slow or too fast; » no real system exists. Typical objectives of simulation supported studies are » to optimize or improve the behaviour of a system » to provide decision support for system design » to put theories to the test » to validate a projected system » to visualize complex interactions in order to understand the system better

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3. METHODOLOGY AND TOOLBOX

Of major importance for producing companies is dynamic thermal modelling (DTM) for buildings. Specifications for this are provided in VDI Guideline 6020. DTM yields the spatial parameters (load or temperature) with reference to all influences such as external climatic conditions, internal loads, transport and operation times – in defined temporal resolution. As a rule, the climate data for a test reference year (TRY) are used for simulations of this kind. A distinction is drawn between static and dynamic DTM procedures. Whereas static programmes draw up energy balances with the aid of factors or key figures, dynamic programmes use mathematical and physical models. Static programmes are in widespread use, but they are suitable only for obtaining answers to simple problems. Dynamic programmes, on the other hand, can also be used for complex systems. Depending on the simulator structure, DTM can be used at various levels of detail in all phases of drafting and planning. These include the following: » preliminary draft » draft » submission » implementation planning, and » tender documents However, this on its own is not sufficient for mapping the complexity of a production system. To secure an overall picture of the impacts of

18

efficiency measures It will also be necessary to map interactions. To be able to assess and analyse energy efficiency measures, a simulation must also take account of the following elements: » weather conditions (e.g. temperature, sun-light, moisture) » the course of the weather (not just temperature averages or heating degree days) » the time pattern of energy demand for production (e.g. electricity, heat, cooling) » interactions between machines or between machines and building (e.g. waste heat and production hall) It is obviously not necessary to apply the same level of detail for every project. The important thing is to select a level of detail commensurate with the task in hand in order to obtain results which are as close to reality as possible while at the same time keeping the costs down. In view of the great variety of tasks and the differences between individual production facilities, it is not possible to give a generally applicable procedure for selecting the level of detail. To demonstrate clearly why simulation models are necessary, a number of practical examples are given below. Example 1 – the effect of temperature reduction One way of cutting down heat energy is to lower the ambient temperature in the case of air heating. This can be put into effect when changes have been made in essential parameters (e.g. work requirements, internal loads) in the production facility. According to a frequently used rule of thumb, a heat energy saving of about 5% can be achieved for each degree of temperature reduction. A simulation of a specimen building shows that heat savings of 8-16% can


3. METHODOLOGY AND TOOLBOX

be achieved for each degree of temperature reduction. There is an interdependence between energy savings, internal loads, the air exchange rate and the selected temperature level. These factors have a significant effect on reduction and determine the savings potential. The numerous dynamic factors (internal loads, air exchange rate, outdoor temperatures) can result in considerable deviations from the calculation by rule of thumb.

reduction is possible because the radiant ceiling panels increase the share of heat radiation in the area, serve to warm up surfaces and help to avoid heating of the air (convection). Despite the lowering of the temperature there is no reduction in comfort for the employees. Example 2 – ventilation technology The energy demand of ventilation systems depends on the processes

20 °C lowered to 19 °C

20 % Reduction of energy demand

18 %

19 °C lowered to 18 °C

16 % 18 °C lowered to 17 °C

14 % 12 % 10 % 8% 6% 4% 2%

Figure 14:

0% Air exchange rate 0 [1/h]

Air exchange rate 2 [1/h]

This simulation result (Figure 14) presents the percentage savings of heat energy in a reference year. In this example the heat input during production hours is 20 kW, with an assumed heat leak from the building of 1 [1/h]9. Various air exchange rates have been entered on the x-axis. For example, the savings for an air exchange rate of 4 [1/h] and a lowering of the temperature to 18 °C come to about 10% (100 MWh/a). The results for this selected example show that the savings can be considerably greater. It can also be seen that there is a high degree of variance in the results. This will significantly affect the assessment of the efficiency of the measure. This approach to calculating heat energy savings also has a bearing on the use of other types of heating, e.g. radiant ceiling panels. Temperature

Air exchange rate 4 [1/h]

Simulation results for temperature reduction

involved or on the internal loads to be dissipated, the ambient conditions and the number of operating hours per year. If use is made of integrated heating and cooling – possibly also with humidification and dehumidification (e.g. ventilation of clean rooms) – it will be necessary to plan energy demand and regulation exactly. Calculations for this purpose are frequently based on heating degree days10, though these show only the average ambient conditions over periods of a month or year. More accurate information on the energy demand of the system can be provided only by a simulation with hourly temperature and humidity values of the outside air at the production facility. Here again the regulation strategy is represented in model form. The simulation makes it possible not only to calculate the electricity, heating and cooling demands but also to

9 1 [1/h] means that the ambient air is exchanged once per hour 10 VDI 2067 or DIN 4108 - 6

Air exchange rate 6 [1/h]

19


3. METHODOLOGY AND TOOLBOX

study regulation adjustments. Through changes in the output parameters or the regulation sequences it becomes possible directly to read off the effects on energy demand. A much more accurate picture of the reduction of energy demand can be obtained in this way. As an example, a model calculated for air conditioning in a clean room shows that 64% of the heating and cooling energy can be saved with regulation of outside air and an integrated heat recovery system. Without the heat recovery between supply air and return air, savings would be only 14%. Table 2: Simulation results for

Scenarios

Savings for heating + cooling 1-year simulation

Savings for heating + cooling Static calculation

Outside air regulation

14 %

45 %

Outside air regulation and heat recovery

64 %

80 %

ventilation technology

The static calculation cannot provide any precise information on these ratios since outdoor temperature, relative humidity and internal loads vary too greatly over a given time period. The relevance of plant simulation for defining effective energy efficiency strategies and calculating energy savings becomes evident. The procedure is equally necessary for the planning and design of the plants. Example 3 – Decentralized energy supply unit In view of the parallel demands for combined heat and power (CHP) and cooling (CCHP) in industrial processes, a decentralized energy supply unit with combined cooling, heat and power generation could offer an efficient solution for the provision of energy. The efficiency and cost effectiveness of the plant are dependent on several

20

parameters – the dimensioning of the plant and the mode of operation, though also on internal and external influencing factors and the load profile of the energy consumer. As part of a static planning the estimated running time of the power supply unit is determined by a sorted load curve. In the case of CCHP the load curve of the cooling requirement will also be included. However, a chronological analysis is not performed. There will be no possibility in this way to investigate regulation adjustments, e.g. in order to cut down peak loads in electricity requirement, or to reduce the use of peak load boilers by anticipatory modes of operation with the aid of storage technologies. With the aid of the simulation, the output from the decentralized energy supply unit for the generation of final


3. METHODOLOGY AND TOOLBOX

energy can be analysed on the basis of the load profiles of each separate type of energy. For this purpose, internal processes are described in a mathematical thermodynamic model, on the basis of which the amounts of producible energy can be calculated. An overall regulation of the internal process parameters will enable the amounts of producible energy to be adapted in the best possible way to the load profile of the energy consumer. The simulation can be used to show a variety of results: » the produced energies (electricity, heat and cooling) » the internal plant parameters (e.g. temperatures and pressures) » plus external factors affecting the overall balance of the energy consumer » possibilities of feeding electricity into the higher-level network » the electricity procurement necessary for fulfilling the demand of the energy consumer » the amount of CO2 emissions saved by the use of renewable energy resources

The examples given above show that there are cases in which certain efficiency potentials can be identified only by the use of simulation models. In particular, simulation serves to increase transparency and thus also to bring out clearly the cause-effect relationship for energy flows in production. Moreover, adequate calculations of savings potentials, and hence also of the economic benefits of energy efficiency measures, can often be made only with the aid of simulations.

In addition to the simulation of the various modes of operation of the plant, the economic benefit of each mode will be analysed. For this purpose the costs will be set against revenues. Thus revenues from payments for energy fed into the grid under the provisions of the renewable energy sources law and the CHP law are set against capital, consumption and operation costs. At the same time the energy costs for the decentralized energy supply unit are set against the energy costs for separate generation of the three energy types.

21


4. PRACTICAL APPROACHES AND RECOMMENDATIONS FOR ACTION

4. Practical approaches and recommendations for action Companies have a number of different areas in which energy efficiency measures can be implemented. A selection of these is presented below, together with approaches and suggestions which may help to sharpen awareness of energy efficiency potentials and serve as a basis for more detailed analyses.

4.1 Generation of electricity and heat

The type of energy carrier is important

Select an efficient provisioning technology

Use solar thermal or geothermal energy for low temperatures

22

An important distinction to be drawn with regard to electricity and heat generation is whether these energies are supplied from outside or produced within the company. If they are produced within the company, attention must be paid to the type of energy carrier. The energy carrier must be tailored exactly to the amounts of electricity and heat needed, with fuel costs and emissions being taken into account. In the case of own generation, consideration should also be given to the possibility of contracting out. For generation of heat, boilers are the method typically found in industry. The use of condensing technology should be investigated here. In view of the current energy market situation, the use of renewable energies should be taken into consideration. A number of different technologies are available here from the economic and ecological point of view. The profitability analysis must also take into account the financial funding available under the renewable energy sources law and the CHP law. Very high efficiency (> 80% or greater) is offered, for example, by combined heat and power (CHP) or combined cooling, heat and power (CCHP). This technology provides electricity and heat via a cogeneration (or trigeneration) plant. Many regenerative raw materials (e.g. biogas, vegetable oil) are suitable as fuels, though fossil fuels (e.g. natural gas) can also be used. With regard to C(C)HP plants it is essential that optimum use should be made of the energy provided. High energy conversion efficiency and the resulting cost benefits of these systems can be realized only if the available heating or cooling is actually used. This makes it important to carry out a detailed dimensioning and to install an intelligent control system. Solar thermal energy is a system which makes very good use of solar radiation for direct (e.g. window areas) and indirect (e.g. collectors) heating of rooms and


4. PRACTICAL APPROACHES AND RECOMMENDATIONS FOR ACTION

drinking water. At certain temperatures it can also contribute towards the provision of process heat. With near-surface geothermal energy, heat pumps are generally used to pump heat or cold via water from soil layers down to depths of up to 150 m. However, not all locations are suitable for geothermal energy, and the investment costs involved are high. When planning the energy supply, it will be necessary to carry out a detailed, time-resolved analysis of the consumption and provisioning structures.

4.2 Uses for cooling | cooling production Cooling in industry is needed mostly for process cooling, though also for air-conditioning in rooms. Where cooling is used, the design or the necessary temperature level must be set against actual requirements. It must also be borne in mind that separate cooling networks are necessary for different temperature levels – this will enable us to be made of the most efficient provisioning system. For cooling production, care must be taken to ensure that the system used is the one most suitable for a particular temperature level or for the required cooling capacity. The cooling system chosen must be ideal for the actual purpose. The following typical technologies are available: » open-air coolers » hybrid coolers » cooling towers » sorption chillers, or » compression chillers These technologies must be designed and evaluated with a view to the constraints of each particular case. Checking should be carried out in the order shown above. In general, free coolers are energy efficient because of their low energy demand. More especially, they reduce the electrical energy demand of compression chillers by reducing their operating hours during periods of low outdoor temperatures (winter relief). In general, it must be remembered that the temperature levels which can be achieved depend on the ambient temperature, which naturally sets a limit to their usefulness. The hybrid cooler is a further development of the free cooler. By introducing fine water droplets it is able to conduct greater amounts of heat away and thus also suitable for use at higher temperatures. Depending on the location, there is also the possibility of using ground water as the cooling medium (near-surface geothermal energy). Where applicable, waste heat can be used for operating sorption coolers, as long as the heat is available at the right temperature level, in the right amounts and at the right time. Use is made in industry mainly of compression chillers. These are notable for their high energy consumption and should for this reason be avoided wherever possible.

The technology chosen depends on the cooling level required Adjust the temperature to the cooling needs of the material concerned

Hybrid coolers lengthen the period of use

Use ground water for cooling

4.3 Compressed air Compressed air is generally a very inefficient medium. Since only 4-7% of the primary energy input is left over as mechanical energy, very sparing use should be made of this form of energy.

Compressed air is inefficient and expensive

23


4. PRACTICAL APPROACHES AND RECOMMENDATIONS FOR ACTION

Use only in exceptional cases

Exactly designed compressed air network

Regular maintenance and testing for leaks

Use of waste heat from centralized generation

Optimum operating point for speed-controlled compressors 40-80%

The use of compressed air As a general rule it is important to start off by checking whether compressed air is necessary at all for the process in question. For drying, cleaning or cooling, other, more efficient, methods are available (e.g. sorption drying, suction or spray cooling). In the case of movement processes, the use of compressed air is acceptable only under certain conditions (e.g. explosion hazard, small constructional size, low weight). Otherwise preference should be given to the use of electric drives. It is important to restrict the use of compressed air as far as possible and to employ alternative technologies. The distribution of compressed air The compressed air supply network should be of optimum length, with minimum losses, exactly dimensioned pipes and ideal storage design. The network pressure should be kept as low as possible (6-10% more energy is required for each extra bar), and, if necessary, different pressure bands should be set up. To reduce pressure losses, leaks should be kept to a minimum. Useful solutions here are low-leak fittings, high-quality quick connect couplings, electric steam traps, and regular inspection and repair of leaks (for which purpose a suitable monitoring system should be installed). In addition, base load measurements should be performed repeatedly to determine leakage losses. From the energy viewpoint it is helpful to install stop valves upstream from seldom used energy consumers and to shut off unused pipes. Pressure regulators, filters and driers should be specifically tested and optimized for each type of energy consumer. The generation of compressed air An important consideration for the generation of compressed air is the location. Although decentralized provisioning in the near vicinity serves to reduce conversion losses, it also prevents waste heat being put to useful effect. Moreover, the energy conversion efficiency of smaller compressors is low. For this reason, if large amounts of compressed air are needed, it may well be more efficient to generate the energy centrally in a technical room and make concentrated use of the waste heat. The waste heat from compressed air can be used, for example, for space heating. At this point, scenario analyses should be carried out before installation is started. The quality of the compressed air should be as high as necessary and as low as possible, since e.g. drying, air filters and other cleaning measures have a marked effect on the energy costs. However, treatment plants will always be necessary and for this reason should be regularly adjusted to the requirements and maintained. Depending on the compressed air requirements over various time periods, it would be worthwhile to use cascade control for the compressors, since compressors should always be run at the optimum operating point. Some of the compressors will then ensure the basic supply, with individual speed-controlled compressors covering the fluctuations in the compressed air network (peak loads).

4.4 Steam Steam is energy intensive

24

Steam is an energy medium used by large-scale consumers for the provision of heat in machines and plants. Whether steam is necessary at all will be decided by the temperature levels and amounts of heat needed for the processes. Steam makes sense only for high temperature levels and for very large amounts of heat. At temperatures below 100 °C the use of steam should be carefully scrutinized in view of the high network losses.


4. PRACTICAL APPROACHES AND RECOMMENDATIONS FOR ACTION

From the energy point of view, the use of steam for space heating should be avoided as far as possible. It should be noted in this connection that a changeover from steam to water as energy carrier will make different pipe cross-sections necessary, which can involve extensive reconstruction work. Such a changeover can also lead to low utilization of boiler capacity and hence to poorer energy conversion efficiency. A further potential is to be found in requirement analysis. From the energy efficiency viewpoint, the dimensioning of the network in large steam networks should be scrutinized with an eye to the actual amounts of steam needed. One indication here is the frequent opening of pressure relief valves. In view of the high temperature level in steam networks, it is essential to ensure good insulation of the pipes in order to minimize convection and radiation losses. Preheating of the feed water with condensate heat (heat recovery) will cut down the energy consumption for evaporating the feedwater. It is advisable in any case to find out to what extent it is possible to make use of condensate heat.

Exact network dimensioning Make use of HR

4.5 Heat recovery (HR) It is important as a general rule to avoid waste heat wherever this makes economic sense. Unavoidable waste heat should always be put to use. Attention must be paid here in particular to differences in temperature levels. A number of different technical concepts can be taken into consideration. The concept offering the highest energy conversion efficiency is direct use of the heat. However, it must be borne in mind here that the heat source, e.g. air, may be contaminated by emissions, thus putting direct use out of the question. Another concept is indirect use, where the heat is put to use via a heat exchanger. Heat exchangers vary in their constraints and energy conversion efficiency rates, depending on the medium and the constructional design. They must be designed specifically for the uses to which they are to be put. It should also be ascertained whether the cooling accruing during processes can be put to use (cooling integration). When hot water is used for heating, the now cooler water can be used for cooling in another area. After it has warmed up again, it will be utilized in the heat-up process. It is important to analyse the various temperature levels and the times and places where they occur. Another possibility for the utilization of waste heat is to be found in energy provision. The heat provided by trigeneration units can be used in other processes, or cooling can be provided by means of a sorption process. Non-synchronous provision and utilization will require either decoupling via storage media or intelligent steering of energy provision and of the processes. Efforts should be made in connection with heat recovery to make use of the heat in a process of similar nature in order to keep the interactions as low as possible. Thus the use of waste heat available throughout the year in processes needing heat only in winter is of doubtful advantage.

Check for every process whether energy can be utilized

HR should always be used if the temperature levels correspond

Timing of demand important

4.6 Thermal insulation Thermal insulation is a measure taken to reduce conversion losses. These are understood to mean heat losses (and hence also cooling losses) due to the passage of heat through the surface areas. The conversion losses are proportional to the surface area and the coefficient of heat transmission (U-value) of the component, and also to the difference between inside and outside temperature. Insulation is divided into three distinct areas: building insulation, pipe insulation and equipment insulation.

Thermal bridges can be energy eaters

25


4. PRACTICAL APPROACHES AND RECOMMENDATIONS FOR ACTION

The insulation of machines is complex

Allow for interactions with room temperature

Buildings: Walls, doors and windows, floors and roofs must be tested for passage of heat and the insulation where necessary improved. Special attention must be paid to the so-called thermal bridges. These are areas in the shell of the building which conduct heat more rapidly (e.g. metal doors), for which reason they should be insulated as far as possible. Inside the building, insulation is needed mainly for hot and cold pipes, and for channels. Machines and plants: Insulation as an option must be tested in each individual case since it may possibly have an impact on the process. Additional insulation may lead to interactions with the indoor climate. If the building is more effectively insulated, it will need less heating energy when outdoor temperatures are low. But if internal heat loads are high, extra cooling may be necessary. However, internal heat loads are considerably affected by the insulation of machines and plants, resulting in the need for more heating or less cooling. For example, insulation of hot pipes increases the need for heating and reduces the need for cooling, apart from the original aim of lowering the energy expenditure for the heated medium.

4.7 Drying technology

Mechanical drying preferable Water evaporation highly energy consuming

Exact design of control system Take account of interactions when introducing a new drying system

26

For product drying, care must be taken to select the most suitable method for drying. The following methods can be used: » thermal processes (heat or cold) » absorption/adsorption » pressure, or » mechanical separation processes (centrifugation, sedimentation) With thermal drying via heat, the evaporation of the water (phase transition) is highly energy consuming. Evaporation takes up five times as much energy as the amount of heating required up to phase transition. In addition, drying plants call for high volume flow rates, which involves even more energy consumption. It is thus advisable to find out whether other methods are more suitable. If thermal drying processes are operated nonetheless, use should be made of heat recovery. This can take place either before the drying process (e.g. use of waste heat from another process for pre-warming of the dryer air) or afterwards (e.g. use of waste heat for space heating). To enhance the efficiency of drying plants, preference should be given to plants or processes with direct heating, since this saves large amounts of conversion losses. Heat insulation plays an important role in thermal drying processes. The control system for drying plants – e.g. regulation of dew point, moisture content of waste air, drying temperature and volume flow – has a major influence on energy demand. Interactions within the production process are connected mainly with the use of waste heat. If thermal drying is replaced by mechanical drying, there will be a considerable reduction in waste heat which might otherwise have been used for downstream processes.


4. PRACTICAL APPROACHES AND RECOMMENDATIONS FOR ACTION

4.8 Indoor climate Air conditioning comprises air exchange and the treatment (e.g. heating, cooling, humidification and dehumidification) of indoor air. Depending on specific requirements, this can involve a considerable energy demand. In ventilation and air conditioning technology, air exchange can take place either via “natural” ventilation (e.g. through windows or air leaks) or via air conditioning plants (ventilation and/or air conditioning plants). With regard to energy efficiency , the use of various systems should be checked with a view to their practicability (necessary air exchange rate, temperature, humidity). Care must be taken to ensure that the ventilation system is geared to the internal loads in order to keep cooling, heating and humidification costs down. Information on internal loads in air-conditioned spaces is thus of central importance. Moreover, the use of recirculated air makes heat recovery possible, provided the return air is free of contaminants. Heat and cold recovery can also be realized with a heat carrier between supply and return air (cf. also heat recovery). The air exchange rate determines the energy demand of the ventilators in the plants, and also the thermal energy demand. The air exchange rate can be cut down in most cases during non-production times (reduced operation mode). In addition, harmful substances or gases should be directly drawn off in order to keep the air exchange rate as low as possible. The energy demand of ventilation systems can be reduced with an intelligent control system which varies the proportion of outdoor air in response to various parameters (temperature of return and outdoor air, demands on supply air). In this way it will be possible to achieve maximum heat recovery and minimize cooling and heating requirements or humidification and dehumidification requirements). Heat losses are another aspect of energy demand reduction in air-conditioning. Attention should be paid here, for example, to the leak tightness of cold storage rooms, the dimensions of the wall areas and heat insulation in general (cf. insulation). Other points to consider are: » pipe dimensioning » pipe routing » filters (maintenance) It is worthwhile to keep room temperatures down wherever possible (subject to workplace regulations or process requirements). In industrial plants, the internal loads, the air exchange rate and the level to which the temperature is reduced have a significant influence on the amount of energy which can be saved. Various heating techniques are available for heating production halls. Two methods worth exploring are air heating (e.g. heater battery) and radiant heating (e.g. radiant ceiling panels). Since they specifically heat the surrounding surfaces, their overall energy demand is low. The demand for heating energy can be lowered by an automated control system with night and weekend temperature reductions.

Consider the type of ventilation Optimum design of air conditioning control system

Reduction of air exchange rate outside production hours

Radiant heaters as a possible alternative

27


4. PRACTICAL APPROACHES AND RECOMMENDATIONS FOR ACTION

4.9 Motors | drives

IE1 motors are the most efficient

FC not useful in full load operation

Select suitable power transmission

Electric motors and drive systems are to be found in practically every production facility. In view of their large number and also of the fact that energy costs make up about 80 percent of the life cycle costs (the sum of the costs over the entire product life cycle) show that efficiency measures in this area are often worthwhile and profitable. Use of high efficiency motor and drive technology must be seen as the most important aspect here. To this end the manufacturers have agreed on standard designations to indicate the degree of energy conversion efficiency. There are three classes, the one with the highest efficiency being Class IE1 (known earlier as EFF1). Already with 4,000 operating hours per year the additional investment pays off in most cases within one year. The overall system should be designed in such a way that none of the elements are overdimensioned. However, it must be borne in mind that an ideal design can make it difficult to extend the system at a later date. A further aspect is the adoption of speed-controlled motors and drive systems. Frequency converters (FC) are used to adjust the input energy to actual demand, with losses being reduced mainly in part load operation. However, the energy consumption in no-load or full load operation is higher than with uncontrolled motors. Attention should always be directed to the system as a whole (motor-couplingtransmission). For power transmission, flat belt drives should be used instead of v-belt drives in order to obtain exemplary coupling of motor and ventilator. The best solution, wherever possible, is to use direct drives. It should be noted as a general rule that the electrical energy of motors and drives is only partly converted into mechanical energy. The losses and every kind of friction will be given off into the surroundings as heat, thus influencing the internal heat loads.

4.10 Pumps Pumps = motors

Throttling control not energy efficient

28

The principal areas for energy efficiency in pumps are much the same as in drive systems, i.e. in design, dimensioning and control. Pumps are also divided into energy efficiency classes, with Class A representing the highest energy conversion efficiency. There is an approximately 22 percent difference in energy demand between one class and the next. Overdimensioning should be avoided if no extensions to the plant are planned, since the pump in this case would not be working at the optimum operating point. Subsequent extensions could then be carried out with a multiple pump system. The possibility of using a multiple pump system with low performance pumps should be considered in systems where previously a single high performance pump was running most of the time in part load operation. Where volume flows are low, a base load pump works at high efficiency, with an extra pump being switched on to cope with peak loads. With regard to control, the use of a frequency converter or a soft start device is an efficient measure for systems with fluctuating demand. No more energy will be put into the transport fluid than is necessary for transport. The revs are controlled to match the discharge head and the volume flow. Bypass or throttle control should be avoided because they have a highly adverse effect on energy conversion efficiency under part load. On account of the greater pressure difference, throttling has the effect of increasing the energy demand compared with unthrottled operation.


4. PRACTICAL APPROACHES AND RECOMMENDATIONS FOR ACTION

4.11 Ventilators Ventilators are used in ventilating, cooling and air conditioning plants. They are driven by electric motors. This means that the efficiency analysis in the case of motors is one aspect of the overall analysis (cf. above, Motors and Drives). Reduction of the energy demand of a ventilator system depends not only on the technical conditions but also on intelligent control. Especially the use of frequency converters (speed-controlled systems) has the effect that lower energy demand can be achieved by a reduction of the amounts of air. In general, it is better to avoid flap and throttle control (cf. above, Pumps). The ventilators should also be adjusted to actual requirement, e.g. by checking the pitch of the fan blades.

Part load operation only with frequency converters

4.12 Lighting Energy efficiency measures for lighting should be focused on the type of light fittings, the light conditions and/or the lighting control. Various lighting concepts can be used, depending on the conditions of production. The efficiency measures will be governed by the circumstances (e.g. the demands made on lighting); typical savings potentials are between 10 and 30 percent. A number of basic measures apply in almost all cases: The replacement of conventional lamps by energy saving lamps and the changeover from standard to 3-band fluorescent tubes including electronic ballast will invariably go hand in hand with an economically advantageous savings potential. A further contribution towards increasing energy efficiency is a lighting concept tailored to actual needs. For this purpose, the illuminance (DIN 12464) required for particular activities must be determined for each separate workplace and brought in line with the lighting of the production hall as a whole. When this has been done, the number and arrangement of the lamps can be decided. Lighting control also offers various possibilities of lowering energy demand. A concept comprising motion sensors, time switches and controlled brightness adjustment can achieve energy savings, though these must be developed with a view to the type of use (e.g. storage aisles to be lit only when entered). In addition, the use of daylight should be allowed for by installing a daylight dependent control. In general, importance should be attached to bright surroundings (lightcoloured wall paint) in order to minimize light absorption. Lighting – depending on type and intensity – will have effects on the necessary heating energy since as a rule less than 20% of the electrical energy is converted into light, the rest being given off into the surroundings in the form of heat. Thus there is an interaction between lighting and space heating – changes in the lighting system may have repercussions on the heating requirements.

Individual lighting concepts

Replacement of fluorescent lamps and electronic ballast

DIN 12464

Interaction with space heating

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5. RESULTS OF THE MODEL PROJECT

5. Results of the Model Project The results presented below are taken mainly from the Hessian Model Project “Energy Efficiency for Largescale Consumers”. After data had been collected from each of the companies involved, the potentials for increasing energy efficiency were analysed and specific measures proposed for putting them into practice. Additional results from other projects will be given below in the chapters “Heating | Ventilation” and “Integrated Heating System”. Table 3: Lighting, frame conditions

Operating conditions Operating time

6,000 h/a 11

CB : 13,000 h EB12 : 20,000 h

Average service life Light intensity

300 lx

Area

4,000 m²

Energy costs Electricity

100 €/MWh

Cost effectiveness Depreciation period

5a

Calculatory interest

30

5.5%

11 CB = conventional ballast 12 EB = electronic ballast

5.1 Lighting For large-scale consumers, the energy expenditure for lighting can make up more than 10 percent of the total energy costs, a fact which is often not fully realized. The purpose of our case study here is to show » how great the savings potential can be for lighting, and » how quickly the necessary measures will pay off. The case in question is a production hall which had already been partly equipped (10 percent) with electronic ballasts (EB). Since the lighting in the hall had been very good even under the earlier conditions, there was no need to make any changes in the light intensity. Two alternatives were analysed. Alternative 1 involved complete replacement of the lamps, Alternative 2 one lamp replacement, and in both cases the use of electronic ballasts.


5. RESULTS OF THE MODEL PROJECT

Optimization potential for lighting without a control system Existing installation

Alternative 1

Alternative 2

Continuous-row luminaire without cover, 2 × 58W/T8, 26 mm

Continuous-row luminaire, with reflector 1 × 54W/T5, 3-band fluorescent lamp

Continuous-row luminaire, without cover, 2 × 58W/T8, 3-band fluorescent lamp

300

192

230

90% CB, 10% EB

100% EB

100% EB

System output/lamp, CB

71 W

-

-

System output/lamp, EB

57 W

52 W

57 W

Connected load

20,880 W

9,984 W

13,110 W

Spec. electr. consumption

5.2 W/m²

2.5 W/m²

3.3 W/m²

125.3 MWh/a

59.9 MWh/a

78.7 MWh/a

332 €/a

217 €/a

175 €/a

- electricity

12,528 €/a

5,990 €/a

7,866 €/a

Total operating costs

12,860 €/a

6,207 €/a

8,041 €/a

-

6,653 €/a

4,820 €/a

Number of luminaires needed

-

192

104

All-in price per luminaire

-

46.68 €

28.00 €

Total price for installation

-

8,963 €

2,898 €

Internal rate of return

-

69%

165%

Static payback period

-

1.35 a

0.6 a

Luminaire/lamp

Number of lamps Type of ballast

Demand Operating costs - lamps

Cost savings Investment costs

The diagram below (Figure 15) sets out the results for the above Table. It shows that Alternative 1 opens up considerable optimization potentials, with 52 percent lower operating costs. The payback period for the 9,000 €

investment costs is 1.35 years. Alternative 2 requires lower investments and cuts the operating costs by 38 percent per year. The payback period is 0.6 years.

Table 4: Lighting, results

31


5. RESULTS OF THE MODEL PROJECT

Investment costs Operating costs per year

14,000 € 12,000 €

Savings per year 10,000 € 8,000 € 6,000 € 4,000 € 2,000 €

Figure 15: Lighting,

0€ Existing installation

Alternative 1

Alternative 2

results overview

The company decided to use luminaires with reflector (Alternative 1). However, the investment was not made in one go – defective luminaires were replaced successively. As a future measure, an intelligent control technology was envisaged, comprising light dimming, presence detectors and personal adjustment options.

5.2. Pump technology Table 5: Pump technology, frame conditions

Constraints Operating hours

6,000 h

Energy costs Electricity unit price

100 €/MWh

Cost effectiveness Service life Calculatory interest

Circulation pumps are the “hidden energy eaters” in most companies. Since factories depend on the work of pumps for their supplies of the various media, an energy efficiency analysis is here of particular relevance. Pumps have long operating times, and for this reason they are among the systems which require large amounts of energy.

32

15 a 5%

A random sample of the pumps in the company showed that they were in the efficiency classes C, D or E. The savings in electrical energy which were obtainable by replacing the old pumps with a new series of high efficiency pumps are shown in Figure 16. For this purpose, a load profile (number of hours at different part loads) was used for calculating the energy demand.


5. RESULTS OF THE MODEL PROJECT

Pump 1

Energy consumption high efficiency pump (kWh)

Pump 2

Energy consumption (kWh)

Pump 3 Pump 4 Pump 5 Pump 6 Pump 7 Pump 8

Figure 16: 0

2,000

4,000

6,000 8,000 Energy consumption [kWh]

10,000

12,000

Pump technology, energy consumption

This comparison was used to calculate the potentials for the various pumps. Table 6:

Optimization potential for pump technology

Pump technology,

Existing pumps

High efficiency pumps

43.7 MWh/a

10.0 MWh/a

4,370 €/a

1,000 €/a

Cost savings

-

3,370 €/a

Investment costs

-

12,600 €

Internal rate of return

-

26%

Static payback period

-

3.7 a

Total energy consumption Operating costs

The possible savings resulting from this come to 33.7 MWh/a or 3,370 €/a, for an investment of 12,600 €. The payback period is 3.7 years, with an internal rate of return of 26%.

results

The company, which had in any case already planned to invest, decided to carry out the replacements on a continuous basis. Special importance was to be attached to the energy efficiency class with regard to the planned investment in the replacement of old pumps, even if the investments involved were higher than those for pumps with lower energy conversion efficiency.

33


5. RESULTS OF THE MODEL PROJECT

Table 7: Granule drying, frame conditions

Operating conditions Synthetics to be dried

3,000 t

Operating time

4,500 h

Dryers decentral/central

50%/50%

Energy costs Electricity

140 €/MWh

Cost effectiveness Service life

10 a

Calculatory interest

5%

5.3 Granule drying

TTable 8: Granule drying,

Some plastic granules have to be dried before further processing, one reason being their hygroscopic properties. Granule drying is notable for its high heat demand. A heat output of 22 kW was calculated for drying at a plastics processing factory. Electric power was calculated at 12 kW for the blower, and at 19 kW for regeneration. This yielded a total of 53 kW for the entire drying process. The dryers were located either decentrally, i.e. in the immediate vicinity of the injection moulding machines, or centrally, i.e. one dryer for several

injection moulding machines. Different values for energy conversion efficiency were obtained for the heat-up process (decentral 65%, central 92%) and for the heat loss during transport in the supply hoses (decentral approx. 8%, central approx. 15%). Thus the net power demand amounted to 240 MWh/a. To determine the energy efficiency potential, two scenarios were analysed: Alternative 1 is a central drying plant with standard operation processes. Alternative 2 additionally includes an optimized operation process.

results

Optimization potential for granule drying Existing plant Type Energy consumption (net) Energy efficiency13

34

Alternative 1

Alternative 2

Decentral

Central

Central

Central

120 MWh/a

120 MWh/a

240 MWh/a

206 MWh/a

53.8%

70.4%

70.4%

70.4%

Total energy consumption

393 MWh/a

341 MWh/a

293 MWh/a

Operating costs

55,000 €/a

47,700 €/a

41,000 €/a

Cost savings

-

7,300 €/a

14,000 €/a

Investment costs

-

100,000 €

110,000 €

Internal rate of return

-

-5%

5%

Static payback period

-

13.6 a

7.8 a

13 Calculated from conduction losses and energy conversion efficiencies in production


5. RESULTS OF THE MODEL PROJECT

The savings with Alternative 2 come to 100 MWh/a (25%), thereby reducing the operating costs to 41,000 €/a. This is equivalent to a cost saving of 14,000 €/a. The central drying plant was more efficient than the decentral concept in both scenarios. The total investment costs for the acquisition of a new dryer and for the necessary connections and hoses are expected to be around 100,000 €. The coordination of the individual processes will incur additional costs of 10,000 €. Reconstruction work made it necessary for the company to develop a new dryer concept. In view of the low operating costs and the better economic key figures, the company decided in favour of Alternative 2.

5.4 Cooling Table 9:

Constraints Operating hours

6,000 h

Utilization rate

75%

Refrigeration technology, frame conditions

Energy costs Electricity

100 €/MWh

Cost effectiveness Service life

15 a

Calculatory interest

5.5%

To ensure that a company has an efficient cooling system which is at the same energy and cost saving, it will be necessary to carry out a detailed analysis of the cooling requirement and the cooling system. Of central importance here are the flow temperatures required in each case in the cooling network. In one of the companies used as an example, the tool cooling cycle runs separately from the hydraulic cooling cycle for machines. The flow temperature of the cooling water for tools is

14 °C, whilst the hydraulic cooling of modern machines works with cooling water temperatures of 30 °C. Tool cooling was already made available from a combination of compression cooling (375 kW) and free cooling (200 kW) for winter relief. At outdoor temperatures of tamb ≤ 7 °C, the free cooler fulfils the cooling function completely. Up to tamb = 12 °C it can be used to pre-cool the medium before in-take into the chiller.

35


5. RESULTS OF THE MODEL PROJECT

From temperatures of tamb ≥ 12 °C the chiller is 100 percent in operation. The savings potential for tool cooling consists of an extension of the cooling concept by an additional 400 kW free cooler.

Table 10: Refrigeration technology, results

Hydraulic cooling has been obtained up to the present time by cooling towers. In view of the required temperature level of 30 °C, the cooling can also be produced from the point of view of efficiency and cost by an free cooler. To cover peak loads, use is made of the well water (10 °C) available at the site.

The investment costs of 36,000 € for the free cooler will pay for themselves after 2.2 years because of the reduced running times of the compression chillers and the costs saved for the cooling tower. The concept of combining different cooling processes with different cooling cycles can also be applied to other companies which have large cooling requirements. Free coolers are here a good supplementary methods of lowering the energy demand of the

Optimization potential for refrigeration technology Existing plant Type Energy demand

Alternative with additional free cooler

Tool cooling

Hydraulic cooling

Tool cooling

Hydraulic cooling

525 MWh/a

30 MWh/a

370 MWh/a

15 MWh/a

Total energy demand

555 MWh/a

385 MWh/a

Operating costs

55,000 €/a

38,500 €/a

Cost savings

-

16,500 €/a

Investment costs

-

36,000 €

Internal rate of return

-

45%

Static payback period

-

2.2 a cooling plants. However, they can work efficiently only at low outdoor temperatures, otherwise the cooling will have to be left to a chiller. An individual cooling concept will have to be drawn up in each case depending on the size of the production site, the necessary amount of cooling and the temperature levels.

36


5. RESULTS OF THE MODEL PROJECT

5.5 Heating | ventilation Table 11:

Energy costs Gas

Heating | ventilation,

45 €/MWh

With regard to heating | ventilation there are numerous interactions inside a production hall, e.g. with the waste heat from machines and lighting. These must be taken into account when designing ventilation systems. In this example, 10 halls – on average about 30 years old – of an industrial firm were analysed. The ground area of 24,000 m² accommodated a large number of machines generating intensive waste heat (e.g. sintering ovens, injection moulding machines).

frame conditions

tion data. The calculated heat energy demand was 6,000 MWh/a, involving annual heating costs of 270,000 €. It emerged from the simulation that up to 10% of the total heat energy could be saved by » a 5 °C night setback in the production areas, and » a lowering of the temperatures in the storage areas to 15 °C. This means immediate savings to the amount of 27,000 €/a without any necessity for investments.

Ventilation s

w do

in

Walls

W

Gate

Lighting

MACHINE

HEATING COOLING

Figure 17: Heating | ventilation, energy flows

Fresh air was provided almost exclusively by natural ventilation (windows, doors, gate). The heat requirements were calculated during the project with the aid of a thermal building simulation. The difficulty here was to draw up a correct estimate of the heat leaks in the buildings and of the air exchange rate provided by natural ventilation. The results of the simulation were verified on the basis of earlier energy consump-

The lowering of the indoor temperatures can be achieved by modifying the control parameters. The age and the run-down condition of the storage halls also offer scope for additional savings potentials: » draught proofing for the shell of the building » improved insulation of the building » replacement of thermal bridges » temperature controlled ventilation flaps.

37


5. RESULTS OF THE MODEL PROJECT

5.6 Interlinked heating system Table 12: Interlinked heating system, frame conditions

Effectivity Energy conversion efficiency/heating

90%

COP14 cooling

2.4

Energy costs Electricity

102 €/MWh

Gas

43 €/MWh

Cost effectiveness Operating life

15 a

Calculatory interest

5%

Waste air Fresh air

Waste heat

Stove

Figure 18:

No waste heat

Compressed air

Interlinked heating system, energy flows

The company concerned here has two adjacent production areas, as shown in the diagram above. Hand assembly workplaces are situated in one of the areas, in which heating is needed particularly in the winter. The adjacent section of the building houses a large number of machines which give off waste air into the surroundings. At the same time there is a certain maximum temperature for this area which must not be exceeded. As a result, intensive area cooling is required throughout the year. Since the ventilation here was underdimensioned, the temperature specifications could not be maintained. For these reasons a search was carried out to find an intelligent, energy efficient solution. To this end a thermal building simulation was performed to

38

produce an interlinked heating system between the two floors and investigate a more powerful controlled ventilation system. When outdoor temperatures are low, it is worthwhile to conduct the warm waste air from the area on the left to the one on the right (cf. Figure 18) and to do without any additional heating. Since the warm waste air is not contaminated by emissions, the heat can be brought over without the need for a heat exchanger. By means of these measures it is possible to reduce the energy costs by 52% (from 20,700 €/a to 10,000 €/a). The costs for conversions to the building come to 50,000 €, with a payback period of 4.7 years.

14 COP (coefficient of performance) is the term used for the thermal energy conversion efficiency of chillers


5. RESULTS OF THE MODEL PROJECT

Optimization potential for interlinked heating system Existing plant Type Energy consumption

Interlinked heating system

Heating

Cooling

Heating

Cooling

204 MWh/a

117 MWh/a

64 MWh/a

71 MWh/a

Total energy consumption

321 MWh/a

135 MWh/a

Operating costs

20,700 €/a

10,000 €/a

Cost savings

-

10,700 €/a

Investment costs

-

50,000 €

Internal rate of return

-

20 %

Static payback period

-

4.7 a Table 13: Interlinked heating system,

25.000 €

results

Costs per year

20.000 € Cost saving 52 % 15.000 € Cooling Heating

10.000 €

5.000 €

Figure 19: 0€ Current state

Interlinked heating system,

Interlinked heating system

results overview

The graph presents the costs for heating and cooling before and after the modifications in the simulation. The concept was partly implemented

because this was made necessary by a change in the conditions of use for the hall.

5.7 Trigeneration Requirement assumptions Electricity

10,000 MWh/a

Heating

6,700 MWh/a

Cooling

900 MWh/a

Energy costs Electricity

95 €/MWh

Heating

63 €/MWh

Cooling

50 €/MWh

Cost effectiveness Service life Calculatory interest

15 a 5.0%

Table 14: Trigeneration, frame conditions

39


5. RESULTS OF THE MODEL PROJECT

Table 15: Trigeneration,

An analysis of energy efficiency within the company must comprise the efficiency of the energy provision itself. In the company in question the injection moulding processes take up the greatest share of the electrical energy. In addition to the electricity demand there is also a need for heating and cooling. Although the machines operate at high temperature during injection moulding and can therefore give off some of their total connected load into the surroundings as heat, allowance must be made for an additional heat demand particularly in the winter months. The cooling requirements, on the other hand, are due to the necessity of tool and hydraulic cooling within the process. Since the demands made by the company on what is now to be an independent heat supply must go hand in hand with the efficiency analysis, decentralized energy supply was considered as an option. The core of the decentralized energy supply is a gas-driven trigeneration plant which generates electrical energy and at the same time, by means of heat exchangers, transports the heat from

cooling water and waste gases into a heating cycle, stores it, and uses it for feeding the heating system. Since the heat accruing during the summer months is not required for heating within the company, it is proposed to use it for cooling by means of an absorption chiller. This has the effect that the electrical energy needed for compression cooling can be saved and replaced by the use of waste heat. It will thus be possible to achieve efficient energy provision and a high utilization rate for the decentralized energy supply (> 80%). Two concepts were set against one another in the profitability analysis: the trigeneration plant running on natural gas compared with a conventional solution using boilers and electricity taken from the grid. The heat demand was calculated with a thermal building simulation, since the heat demand over the course of the year is in many cases unknown, or can only be estimated. According to the plan, the energy was to be provided by two trigeneration plants designed to match the heat demand. Electricity, heating and cooling for the site are produced with outputs of 340 kWel and 481 kWth. The chiller has an output of 375 kWel, the supplementary boiler for covering peak demands 1 MWth. The following Table shows the most important results of the planning.

results

Optimization potential of trigeneration Conventional solution

Trigeneration plant

Electricity

10,000 MWh/a

10,000 MWh/a

Heating

6,700 MWh/a

6,700 MWh/a

Cooling

900 MWh/a

900 MWh/a

1,570,000 €/a

1,300,000 €/a

Cost savings

-

270,000 €/a

Investment costs

-

1,000,000 €

Internal rate of return

-

26%

Static payback period

-

3.7 a

Annual plant costs

40


5. RESULTS OF THE MODEL PROJECT

The operating costs for the energy supply unit are lower than the energy consumption costs for the boiler alternative because of the higher degree of fuel utilization and hence the more favourable production of the necessary energy. The cost savings are based on the difference between the annual plant costs for the previous heating alternative and those for trigeneration. The result was that the higher investment costs will pay for themselves in just under 3.7 years.

5.8 Simulation supported energy efficiency analysis To study the overall energy efficiency in the present example, a simulation model was prepared with the aim of mapping the separate energy flows and their linkages. This was used to find out how energy and costs could be saved both by individual measures and by rational interconnections of the energy flows. In a plastic processing plant components are produced by injection moulding and subsequently assembled in a separate process to modules. The production area is divided into two units – injection moulding and the assembly area. The Tables below present the salient data for energy (Table 16) and for the company’s machines and plants (Table 17). Analysis of the company’s energy balance shows that the heat for the machines and plants is very often produced by electricity. Moreover, the

Energy costs Electricity price

0.11 €/kWh

Gas price

0.05 €/kWh

Granule throughput

1,500 t/a

Energy demand Electricity demand

5,350 MWh/a

Heat demand

1,000 MWh/a

Table 16:

Cooling requirement

2,560 MWh/a

Frame conditions,

Compressed air requirement Machines/plants

Hall 1 (8,000 m³)

Hall 2 (4,000 m³)

1.28m m³/a Number

Electricity demand

Injection moulding machines

20

56 kW

Drying plants

2

49 kW

Lighting

1

18 kW

Air compression system

1

40 kW

Assembly plant

5

6 kW

Lighting

1

15 kW

simulation supported energy efficiency analysis,

Table 17: Machines and plants, simulation supported energy efficiency analysis

41


5. RESULTS OF THE MODEL PROJECT

source of mechanical energy is almost entirely compressed air. The heat demand for the injection moulding area is 2,240 MWh/a. All of the plants give off heat into the hall, with the result that there is a heat surplus of 970 MWh/a over and above the actual heat demand. The excess heat is drawn off by the ventilation system and thus remains unutilized. In the assembly hall, on the other

The energy balance yielded an overall power demand of 7,040 MWh/a and a gas demand of 1,240 MWh/a, resulting in annual energy costs of 836,000 €. The situation shows a considerable savings potential, which was presented in detail on the basis of energy efficiency measures within the simulation model. For this purpose, two alternatives were investigated.

Energy supplier

Lighting Electricity: 160 MWh

Heat: 150 MWh

Granule drying Heat: 450 MWh

Electricity: 450 MWh

Electricity: 4,610 MWh

IMM

Heat: 2,050 MWh

Hall 1: Production

Electricity: 1,020 MWh

Compression chiller

Compressed air: 349,000m³ Heat: 570 MWh

Cooling: 2,560 MWh Electricity: 670 MWh

Air compressor Lighting

Figure 20: Annual energy flows in

Electricity: 130 MWh

Gas: 1,250 MWh

Heat: 120 MWh

Compressed air: 930,000 m³

Assembly

Heating Heat: 1,000 MWh

the initial situation, simulation supported energy

Hall 2: Assembly

efficiency analysis15

hand, there is a heat demand of 1,000 MWh/a, which is covered by a gasdriven heating boiler. Figure 20 shows the company’s energy flows in terms of quantity without reference to the time factor.

42

Alternative 1: Reduction of transformation losses and heat recovery Alternative 1 comprises direct gas heating of the injection moulding machines and the granule drying plant. The compressed air processes, for example, are replaced by the use of servo motors. Another feature is a thermal energy recirculation (heat recovery) between the injection moulding machines and the granule dryers. The waste heat still available is

15 IMM = injection moulding machine, chiller = compression chiller


5. RESULTS OF THE MODEL PROJECT

used for providing cooling by means of an absorption chiller. However, since this will not cover the entire cooling requirements for the injection moulding machines, it will still be necessary to use a compression chiller. A comparison between the initial situation and this alternative shows clearly that the direct heating has reduced the electricity demand of the injection moulding machines by

and the increased use of natural gas, reduce the electricity demand by 1,900 MWh/a. At the same time the gas demand rises by 2,060 MWh/ha. The energy costs go down by 110,000 €/a. The primary energy demand is thus lower compared with the initial situation, since there are high conversion losses in the upstream stages of the electricity provision.

Energy supplier

Lighting Heat: 150 MWh

Electricity: 160 MWh

Gas: 250 MWh

Granule drying Heat: 140 MWh

Electricity: 100 MWh Heat: 40 MWh

AC

Heat: 0 MWh

Heat: 100 MWh

Heat: 0 MWh

Hall 1: Production

Cooling: 30 MWh Gas: 1,020 MWh Electricity: 1,010 MWh

Electricity: 3,580 MWh

Heat: 820 MWh

IMM Heat: 1,130 MWh

Cooling: 2,530 MWh

Compression chiller

Electricity: 100 MWh Heat: 960 MWh

Gas: 2,320 MWh

Assembly Heat: 40 MWh

Heating

Annual energy flows for

Heat: 120 MWh

Alternative 1,

Electricity: 130 MWh

Lighting

Figure 21:

Hall 2: Assembly

simulation supported energy efficiency analysis16

1,030 MWh/a. On the other hand, the gas demand is higher, which involves lower specific energy costs and thus serves to cut the costs. The efficiency measures bring about a reduction of the internal loads and hence an increase in the heat demand. The energy flows resulting from implementation of the measures are illustrated in Figure 21. The improvements in this alternative, in particular the efficient heat recovery

Alternative 2: Use of trigeneration This variation includes, in addition to Alternative 1, energy provision from a gas-driven trigeneration (CCHP) plant, the heat from which is used both for space heating and for the provision of cooling via the absorption chiller. The compression chiller and the heating boiler are now no longer necessary. To make this clear, the energy streams are illustrated in Figure 22.

16 IMM = injection moulding machine, AC = absorption chiller, chiller = compression chiller

43


5. RESULTS OF THE MODEL PROJECT

Energy supplier

Lighting Electricity: 160 MWh

Heat: 150 MWh

Granule drying Gas: 250 MWh Gas: 12,900 MWh Electricity: 1,090 MWh CCHP

Heat: 140 MWh

Electricity: 100 MWh Heat: 40 MWh

Heat: 1,130 MWh

AC Heat: 550 MWh

Heat: 3,410 MWh Heat: 0 MWh

Cooling: 2,560 MWh Heat: 100 MWh

Electricity: 3,580 MWh

Hall 1: Production

Heat: 0 MWh

IMM Gas: 1,020 MWh Heat: 1,750 MWh

Assembly

Figure 22:

Electricity: 100 MWh

Heat: 40 MWh

Annual energy flows for Alternative 2,

Electricity: 130 MWh

Lighting

simulation supported

Heat: 120 MWh

Hall 2: Assembly

energy efficiency analysis17

With this alternative the electricity demand is reduced by 2,900 MWh/a compared with the initial situation. The gas demand is 12,260 MWh/a higher. Because of the heat-controlled operation the trigeneration plant produces more electricity than is needed for production requirements, and the surplus is fed into the electricity supply grid. The annual energy costs are reduced – partly due to the feed-in tariff for the trigeneration current – to 470,000 €/a. The resulting cost savings compared with the initial situation amount to 368,000 €/a.

Results overview Figure 23 shows the change in the relative shares of electricity and gas for energy provision compared with the initial situation. The energy concept is converted successively to greater use of gas, since this is advantageous in terms of primary energy and also from the financial viewpoint. Figure 24 presents the primary energy demand resulting from the simulation, in which Alternative 2 shows a much lower primary energy demand. The reason for this is the higher energy conversion efficiency of trigeneration.

Gas demand Electricity demand

Initial situation

Alternative 1

Figure 23: Results for

Alternative 2

energy provision, simulation supported

-2,000 MWh

2,000 MWh

6,000 MWh

10,000 MWh

energy efficiency analysis

44

17 IMM = injection moulding machine, AC = absorption chiller, CCHP = trigeneration plant

14,000 MWh


5. RESULTS OF THE MODEL PROJECT

The measures also result in an overall reduction in costs, as can be seen from Figure 25.

Initial situation

Alternative 1

Figure 24:

Alternative 2

Results for 0 MWh

10,000 MWh

20,000 MWh

30,000 MWh

primary energy demand, simulation supported

Primary energy

energy efficiency analysis

Gas costs Initial situation Electricity costs Alternative 1

Alternative 2

Figure 25: -400k €

-200k €

0k €

200k €

400k €

600k €

800k €

1.000k €

Costs

Results for costs, simulation supported energy efficiency analysis

The payback period for both alternatives is about 3 years, on the assumption of a replacement investment (i.e. immediate substitution). In the case of a reinvestment (substitution due to wear and tear) the payback period is reduced to about 2 years. This example shows that simulation technology is a suitable tool for analysing the linking of energy flows. Thus it can be used as a basis for evaluating technical, ecological and economic factors.

With the aid of simulation technology it is possible to register and analyse complex interactions in temporal resolution and to identify ideal combinations. The results of a simulation can be applied only to a limited extent to a comparable production facility, since the simulation requires the specific production conditions of the company to be taken into account. Even what may appear to be merely secondary factors can have a decisive influence on the profitability results for an overall concept.

45


6. APPENDIX

6. Appendix 6.1 Authors | project partners

46

deENet

DeENet – Kompetenznetzwerk Dezentrale Energietechnologien – is a registered association based in Kassel. It was founded in January 2003. deENet describes itself as a business and research network in the field of decentralized energy technology and energy efficiency. The aim of the network is to develop integrated systems solutions for energy supplies. This development is governed by increasingly decentralized local structures, making use as far as possible of renewable energies, and by demands – not least of all on the part of consumers – for massive improvements in efficiency. For these reasons, the activities of deENet are focused on decentralized supply technology, energy-optimized planning and building, energy-efficient industrial processes and sustainable supply concepts. Its competences and long-established cooperation structures, will bring about integrated supply solutions not only for individual objects or settlements but also across entire regions. In addition, the aim behind the structural networking and the selective promotion of cooperation within the network is to further the development of new products and services, to effect long-term improvements in the economic power of the region and to create safe jobs for the future. Since the beginning of 2007, deENet has been a member of Kompetenznetzwerke Deutschland, the innovation initiative of the German Ministry of Economics.

Limón GmbH

Limón GmbH is a spin-off of the University of Kassel, specializing in the simulation and control of production and energy systems. These activities include the performance of simulation studies for production plants with a view to realizing optimizations of complex plants which would be impossible without the aid of dynamic mapping. Energy efficiency studies are also performed for manufacturing companies, where again use is made of simulation models. Customers include medium-sized and large companies in various sectors of industry. Limón GmbH has availed itself of research work at the University of Kassel to develop a simulation system which makes it possible to map production together with energy and material flows. This simulation system provides a decisive basis for the mapping of interactions within a factory, such as those described above. The company’s additional know-how in connection with control systems is used to support the development of energy-efficient production control.


6. APPENDIX

The Department of Environmentally Sustainable Products and Processes is active primarily in the areas of energy efficiency enhancement and the introduction of renewable energy carriers in production processes. The research activities of the Department are divided into the three following areas: 1. Climate, energy and resource efficient production 2. Modelling, simulation and control of production and the production environment 3. Decentralized energy supplies and renewable energies in production Common to all research activities is the interdisciplinary approach with attention to entire life cycles. The Department has already handled a number of projects centred round individual aspects of these subject areas: Climate friendly plastics production with the aid of systemic energy efficiency, development of a global production concept for a medical engineering company, efficient decentralized energy supply unit with anticipatory control strategies, a CO2e neutral factory, energy efficiency by optimized coordination of production and energy (ENOPA), material efficiency and resource conservation (MaRess).

upp – Fachgebiet für „Umweltgerechte Produkte und Prozesse“ an der Universität Kassel

CONTACT HESSEN MODELLPROJEKTE Manuel Sturm Project Manager Environmental and Energy Technology

6.2 HessenModellProjekte Funding for applied research and development projects The State of Hessen also provides funds for the performance of especially innovative research and development projects in the fields of environmental and energy technology. Funds are made available within the Hessen ModellProjekte programme to cover up to 49% of the costs for research and development projects realized on a cooperative basis by several partners (small and medium sized companies, universities, research facilities).

HA Hessen Agentur GmbH Abraham-Lincoln-Str. 38-42 65189 Wiesbaden Tel.: 0611-774-8953 Fax: 0611-774-58953 manuel.sturm@hessen-agentur.de www.innovationsfoerderung-hessen.de

At the present time two measures are available for the funding of such projects: » LOEWE (State Offensive for the Development of Scientific and Economic Excellence, with funding line 3: LOEWE-KMU for joint projects with small and medium sized companies, and » Model and Pilot Projects (MPP) for small and medium sized companies. The eligibility criteria for funding include degree of innovativeness, exploitation potential, technology transfer and competence of the partners. As an indispensable first step towards obtaining funds, a draft outline must be submitted before the start of the project. Hessen’s business promotion company HA Hessen Agentur GmbH acts as project manager and acts as counterpart not only during the application phase but also over the entire course of the project.

Measures

All documentation and further information can be found at www.innovationsfoerderung-hessen.de. Funded by Hessisches Ministerium für Wirtschaft, Verkehr und Landesentwicklung Hessisches Ministerium für Wissenschaft und Kunst

EUROPÄISCHE UNION: Investition in Ihre Zukunft – Europäischer Fonds für regionale Entwicklung

47


6. APPENDIX

6.3 Aktionslinie Hessen-Umwelttech and Hessen-PIUS

Hessen

Umwelttech

CONTACT HESSEN-UMWELTECH Aktionslinie Hessen-Umwelttech Dr. Carsten Ott, Projektleiter Dagmar Dittrich HA Hessen Agentur GmbH Abraham-Lincoln-Str. 38-42 65189 Wiesbaden Tel: 0611-774-8350, -8645 Fax: 0611-774-58350, -58645 carsten.ott@hessen-agentur.de dagmar.dittrich@hessen-agentur.de

The Action Line Hessen-Umwelttech is the central platform set up by Hessen’s Ministry of Economics for the environmental technology sector. It strengthens the competitiveness and innovative power of Hessian manufacturers and service providers in the field of environmental technology and acts as an interface to environmental technology users – particularly with a view to Production-Integrated Environmental Protection (PIUS). The Aktionslinie provides information, communication and cooperation possibilities for environmental technology providers and users, e.g. from the sectors of waste technology, waste water and water technology, energy technology and air pollution control. It advises companies, promotes technology transfer und markets the expertise of the environmental technology sector in Hessen. Services available to companies from Hessen-Umwelttech: » up to date branch information in Hessen-Umwelttech’s printed newsletter NEWS (quarterly) and also in its E-Mail NEWS (monthly) » information brochures and guide-lines centred round special themes » congresses and workshops for exchanging information and establishing contacts » participation at exhibition stands organized by Hessen-Umwelttech » innovation radar environmental law: up-to-date information on market potentials arising out of amendments to environmental legislation » Hessen-PIUS: arranging for information and publicly sponsored advisory services related to Production-Integrated Environmental Protection in Hessen » central contact agency offering “piloting” services for all matters connected with environmental technology

www.hessen-umwelttech.de

HA Hessen Agentur GmbH is charged with the implementation of the Aktionslinie Hessen-Umwelttech. The one hundred percent subsidiary of the State of Hessen bundles all non-monetary activities of Hessen’s business development. The Action Line Hessen-Umwelttech is the central interface for the field of environmental technology and in its “pilot” function works closely together with various organizations such as: » Hessen ModellProjekte, » Technology Transfer Network (TTN), » Advisory Centre for Business Development » the Hessian point of contact for the “Enterprise Europe Network”, » the Hessen Transfer Office for International Emissions Trading » the Hessen Hydrogen and Fuel Cell Initiative

Innovation Radar on Environmental Legislation A special service of Aktionslinie Hessen-Umwelttech is the Innovation Radar Environmental Law. Starting out from the idea that environmental law provides economic impulses for the development and application of innovative technologies, the Innovation Radar gives most up-to-date information on legal amendments and their economic impact on various environmental technology segments. A regularly updated version is available on the homepage of the Aktionslinie HessenUmwelttech. In addition, a summary of the major legal acts of market relevance appears every three months in the Hessen-Umwelttech NEWS.

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48 www.hessen-umwelttech.de (Rubrik Innovationsradar Umweltrecht)


6. APPENDIX

Hessen-PIUS®: Protecting the environment – lowering the costs It is becoming ever more important for companies to use their resources economically. To this end, Production-Integrated Environmental Protection (PIUS) provides an effective instrument and opens up interesting opportunities for both environmental technology providers and users. For this reason, the Hessian Ministry of Economics has initiated a PIUS advisory programme for small and medium-sized firms in Hessen. The purpose of this is to help optimize in-house processes with a view to an efficient handling of resources such as energy, water, air, raw materials, consumables and supplies, with all the resulting savings in cost. The PIUS advisory programme project is run by RKW Hessen GmbH. The Action Line Hessen-Umwelttech coordinates all other activities related to Hessen-PIUS and since 2008 has been a cooperation partner on www.pius-info.de, Germany’s most frequently used PIUS portal with around 25,000 individual page views a month. The PIUS portal is operated and financed jointly with the Efficiency Agency North-Rhine Westphalia (EFA) in Duisburg and the special waste management company Sonderabfall-Management-Gesellschaft Rheinland-Pfalz mbH (SAM) in Mainz.

CONTACT RKW HESSEN GMBH

Publicly sponsored advisory service: The Hessian Ministry of Economics and the European Regional Development Fund contributes an amount of up to 8,000 euros (9,000 euros in ERDF priority areas) for a PIUS consultation over a three-year period for a small or medium-sized firm. The programme covers not only improvements in production processes but also points up opportunities for service providers and commercial enterprises to organize their activities in an environmentally friendly and efficient way.

RKW Hessen GmbH Kay Uwe Bolduan Düsseldorfer Str. 40 65760 Eschborn Tel.: 06196-9702-55 Fax: 06196-9702-99 pius@rkw-hessen.de

PIUS® is a registered trade mark of the Effizienz-Agentur NRW.

www.rkw-hessen.de www.hessen-pius.de

49 www.hessen-pius.de


3. METHODOLOGY AND TOOLBOX

Publication Series by Aktionslinie Hessen-Umwelttech, affiliated to the Hessian Ministry of Economics, Transport, Urban and Regional Development The following titles are available in English language: Volume 1

Uses of Nanotechnology in Environmental Technology in Hessen Innovation potentials for companies

Volume 8

A Practical Guide to Energy Efficiency in Production Processes

Volume 10 Competence Atlas Water Water technologies and Water management in Hessen Volume 11 Competence Atlas Waste Waste Management, Waste Technology and Resource Efficiency in Hessen

Information/ Download/ Ordering

www.hessen-umwelttech.de

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Hessen

Umwelttech

www.hessen-umwelttech.de

managed by:

EUROPEAN UNION Investing in your future – European Regional Development Fund

The project is co-financed by means of the European Union

A Practical Guide to Energy Efficiency in Producti  
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