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The present edition constitutes part of a series of three Training Guides published by versions of the Guide Combined heat and power CHP systems

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The present edition constitutes part of a series of three Training Guides published by the. partnership of the SAVE II Programme 1999 project with Contract No XVII 4 1031 Z 99 021. entitled Guide for the Training of Engineers in the Combined Heat and Power related issues. More specifically this is the English version of the Training Guide which is completed with the. Greek and German versions of the Guide prepared by the Centre for Renewable Energy. Sources CRES and the Zentrum f r rationelle Energieanwendung und Umwelt GmbH ZREU. respectively, The aim of these publications is to comprise a useful and practical tool for Engineers and other. scientists that are going or wish to be occupied in the field of Cogeneration or Combined Heat. and Power CHP The project was co financed from the SAVE II Programme of the Directorate. General for Energy and Transport DG TREN of the European Commission Dr Charalambos. Malamatenios who is the Head of CRES Training Department coordinated the project that was. implemented from January 2000 until June 2001, CRES the project contractor prepared Chapters 2 Mr E Mathas 3 5 and 8 all three prepared. by Mr St Mengos collaborator of CRES Training Dept of the Guide Mr P Choustoulakis and. Dr Ch Malamatenios were also involved in the preparation of texts on behalf of the CRES. Training Dept The German partner ZREU carried out Chapters 1 4 6 and 8 whose authors. were Mr Klaus Grepmeier Dr Alexandra Babeck and Mrs Cosima M ller The unification of all. texts together with any corrections and or additions needed in order to be presented as one. and continuous script was made by Dr Ch Malamatenios Head of CRES Training Dept. The views expressed in this publication do not necessarily. reflect the view of the European Commission which co. financed the production of the Guides The partners CRES. and ZREU and the European Commission neither make any. warranty or representation expressed or implied with respect. to the information contained in this report nor assume any. liability with respect to the use of or damages resulting from. the use of this information,1 COGENERATION BASICS OF OPERATION. 1 1 THE CONCEPT OF COGENERATION,1 2 COGENERATION PRINCIPLES. 1 2 1 Heat engines,Internal combustion engines,1 2 2 1 Otto cycle.
1 2 2 2 Diesel cycle,Gas turbines,1 2 3 1 The Brayton or Joule cycle. Steam turbines,1 2 4 1 The Rankine cycle,1 2 4 Combustion principles. 1 2 5 1 Fuel types,1 2 5 2 Heating values of fuels. 1 2 5 3 Combustion emissions,Performance indices of cogeneration systems. CLASSIFICATION OF COGENERATION SYSTEMS,Types of cogeneration concepts.
1 2 6 Operation modes of cogeneration systems,2 CHP SYSTEM MAIN COMPONENTS. 2 1 PRIME MOVER OPTIONS,2 1 1 Introduction,Reciprocating Engines. Gas turbines,Steam Turbines,Micro turbines,2 1 4 Fuel cells. Technology summary,ELECTRIC POWER GENERATORS,2 1 6 Principles of electrical machines. Synchronous machines,2 1 7 Asynchronous induction machines.
Generator selection,HEAT RECOVERY,Heat recovery options. Heat recovery boilers,Heat recovery in reciprocating engines. 2 2 3 Heat recovery in steam turbines,Gas turbine heat recovery. 2 2 4 Heat recovery in micro turbines and fuel cells. CONTROL AND MONITORING SYSTEMS,Control systems,Long term performance monitoring. 3 AUXILIARIES INTERCONNECTIONS INTERFACES,3 1 HEAT RECOVERY AND DISTRIBUTION DEVICES.
3 1 1 Heat recovery boilers and the exhaust system. Supplementary and auxiliary firing,Heat output from the CHP package. Distribution of heat,3 1 4 1 Valves and fluid handling devices. 3 1 4 2 Steam lines considerations,FUEL SUPPLY SYSTEMS. Natural gas supplies,Coal oil and other fuels supplies. ELECTRICAL SUPPLY SYSTEMS,Utility interconnections.
Voltage regulation,Fault control,Protection,3 3 1 TECHNOLOGICAL ISSUES OF CONCERN. Trigeneration and absorption cooling,3 3 2 3 4 1 1 The concept of Trigeneration. 3 4 1 2 Chillers,3 3 3 Silencers,3 4 2 1 Acoustic housings and enclosures. 3 3 4 3 4 2 2 Other ways of noise attenuation,4 COGENERATION APPLICATIONS. 4 1 INTRODUCTION,4 2 TERTIARY SECTOR,4 2 1 Background.
Case study Jurys Hotel and Towers DUBLIN,4 2 3 INDUSTRY. Background,4 3 Case study Buchanan Flooring,4 3 2 1 Electricity uses. 4 3 2 2 Plant overview,4 3 2 Outlook,DISTRICT HEATING COOLING. Background,4 3 3 System components,Thermal energy generation. 4 4 Case study Lutherstadt Wittenberg, 4 4 1 Case study District heating of Cham Switzerland.
4 4 5 1 The principle of operation,4 4 2 4 4 5 2 Economics. APPLICATIONS ACCORDING TO THE PRIME MOVERS,Application of reciprocating engines. 4 4 4 Application of steam turbines,Application of gas turbines. 4 4 5 Application of fuel cells,5 CHP SYSTEM SELECTION. 5 1 INITIAL CONSIDERATIONS,5 1 1 Introduction,Considerations for CHP project development.
PROCEDURE FOR SYSTEM SELECTION AND DESIGN,Background. Preliminary assessment,Feasibility study and system selection. 5 2 2 Identifying a CHP plant of an appropriate output. Detailed design,ASSESSMENT OF IMPORTANT TECHNICAL PARAMETERS. 5 2 4 Site energy demands,5 3 1 1 Future energy demands. 5 2 5 5 3 1 2 Timing of demands, Factors affecting the selection of the suitable CHP plant.
5 3 5 3 2 1 Heat to power ratio,5 3 2 2 Quality of thermal energy needed. 5 3 2 3 Fuel supply,5 3 2 4 Noise levels,5 3 2 5 Other issues of concern. 5 3 2 6 Regulatory and local planning issues,FINANCIAL ASSESSMENT OF A CHP PROJECT. Key parameters for the economic analysis,Tools for the financial analysis of CHP projects. Assessment of financial feasibility of CHP projects. Sensitivity analysis,6 LEGAL STATUS FINANCING OPPORTUNITIES.
6 1 LEGAL AND INSTITUTIONAL FRAMEWORK CONDITIONS,6 1 1 Background. 6 1 2 European Union law, 6 1 2 1 Communication from the Commission to the Council and the European. Parliament A Community strategy to promote combined heat and power. and to dismantle barriers to its development 15 10 97. 6 1 2 2 European Union programmes supporting CHP,6 1 2 3 Internalisation of external costs. 6 1 2 4 Action plan to improve energy efficiency in the European Community. 6 1 2 5 Directive concerning the common rules for the internal market in electricity. 6 1 2 6 EU Directive on the promotion of electricity from RES in the internal market. The situation in Germany, 6 1 3 1 Law for the protection of the production of electricity produced from. combined heat and power plants,6 1 3 2 The ecological tax reform.
6 1 3 3 Renewable Energy Law,The situation in Greece. 6 1 4 1 Overview, 6 1 4 6 1 4 2 The Operational Programme for Energy OPE. 6 1 4 3 Other relevant laws,The situation in other EU countries. FINANCIAL INSTRUMENTS,6 1 5 Financing problems,On balance sheet financing options. 6 2 2 1 Internal funding,6 2 2 2 Debt finance,6 2 2 3 Leasing.
6 2 2 Off balance sheet financing options,6 2 3 1 Equipment supplier finance. 6 2 3 2 ESCO contracts,Making the choice between options. Joint Ventures,7 CHP SYSTEM INTEGRATION AND COMMISSIONING. 7 1 PROJECT IMPLEMENTATION,7 1 1 Possible implementation routes. 7 1 1 1 In house resources,7 1 1 2 Turnkey procedure.
7 1 1 3 Integrated energy services procedure,Specification of requirements. 7 1 2 The tender and design procedure,7 1 3 1 In house resources projects. 7 1 3 2 Turnkey projects,7 1 3 3 Energy services contract projects. Project risks and project management,CONTRACTUAL TERMS RESPONSIBILITIES AND LIABILITY. 7 1 4 Background,Design and construction contract,7 2 Operation and maintenance contracts.
7 2 1 Off take contracts,INSTALLATION OF A CHP SYSTEM. Managing the installation,7 3 3 1 In house resources project. 7 3 3 2 Turnkey project,7 3 3 3 Energy services contract project. Minimising the disruption,Varying the specification. 7 3 1 COMMISSIONING AND TESTING PROCEDURE,Background.
Types of tests,Specific aspects of CHP project testing. 8 CHP SYSTEM OPERATION MAINTENANCE,8 1 INTRODUCTION. 8 2 CHP PLANT OPERATION,8 2 1 Basics of operation,CHP plant control strategy. 8 2 2 8 2 2 1 Control systems associated with individual plant items. 8 2 2 2 Monitoring and advisory systems, 8 2 2 3 Distributed systems for total plant control. 8 2 2 4 Manual control of individual plant systems. Planning and managing plant shutdowns,Staff training.
Safety issues relating to plant operation,CHP PLANT MAINTENANCE. Maintenance options,Maintenance contracts for CHP plant. Maintenance requirements for CHP prime movers electrical generators. 8 3 8 3 3 1 Gas turbines,8 3 1 8 3 3 2 Reciprocating engines. 8 3 3 3 Steam turbines,8 3 2 8 3 3 4 Micro turbines. 8 3 3 5 Fuel cells,8 3 3 Maintenance requirements for site systems.
CHP PLANT PERFORMANCE MANAGEMENT,Importance of the efficient system management. Plant condition monitoring,Auditing CHP plant performance. Plant performance monitoring,APPENDIX 1,1 BASICS OF OPERATION. 1 1 THE CONCEPT OF COGENERATION, Combined heat and power CHP systems also known as cogeneration generate. electricity and or mechanical energy and thermal energy in a single integrated. system see figure 1 1 This contrasts with common practice where electricity is. generated at a central power plant and on site heating and cooling equipment is. used to meet non electric energy requirements The thermal energy recovered in a. CHP system can be used for heating or cooling in industry or buildings Because. CHP captures the heat that would be otherwise be rejected in traditional separate. generation of electric or mechanical energy the total efficiency of these integrated. systems is much greater than from separate systems. Figure 1 1 Conventional energy system versus cogeneration system. CHP is not a specific technology but rather an application of technologies to meet. end user needs for heating and or cooling energy and mechanical and or electrical. power Recent technology developments have enabled new CHP system. configurations that make a wider range of applications cost effective New. generations of turbines fuel cells and reciprocating engines are the result of. intensive collaborative research development and demonstration by government. and industry Advanced materials and computer aided design techniques have. dramatically increased equipment efficiency and reliability while reducing costs and. emissions of pollutants, Conventional electricity generation is inherently inefficient converting only about a.
third of a fuel s potential energy into usable energy The significant increase in. efficiency with CHP results in lower fuel consumption and reduced emissions. compared with separate generation of heat and power CHP is an economically. productive approach to reducing air pollutants through pollution prevention whereas. traditional pollution control achieved solely through flue gas treatment provides no. profitable output and actually reduces efficiency and useful energy output. The efficiency of the overall system results from an interaction between the individual. efficiencies of the power and heat recovery systems. Since there are two or more usable energy outputs from a CHP system defining. overall system efficiency is more complex than with simple systems The system can. be viewed as two subsystems the power system which is usually an engine or. turbine and the heat recovery system which is usually some type of boiler The. efficiency of the overall system results from an interaction between the individual. efficiencies of the power and heat recovery systems. The most efficient CHP systems exceeding 80 percent overall efficiency are those. that satisfy a large thermal demand while producing relatively less power As the. required temperature of the recovered energy increases the ratio of power to heat. output will decrease The decreased output of electricity is important to the. economics of CHP because moving excess electricity to market is technically easier. than is the case with excess thermal energy However there currently are barriers to. distributing excess power to market, Table 1 1 Overall view of CHP systems Source Onsite Sycom 1999. Heat and power stations Block type thermal power stations. Heat and Combined cycle Block type Block type Micro scale. power station station with gas thermal power thermal power CHP unit with. with steam turbine station with station with car engine. turbine gas turbine industrial, Driving system Steam turbine Gas and steam Gas turbine Industrial Otto. turbine s engine with,combined three way,diesel engine. converter2, Fuel Coal heavy oil Natural gas fluid gas light Natural gas fluid gas biogas. fluidised bed heating oil gasified coal in the sewage works agriculture. combustion future waste dump gas light heating,natural gas oil biogenic fuels.
heating oil,conventional,steam vessel, Level of Up to 500 C Up to 300 C Up to 550 C Up to 100 C Up to 100 C. temperature, Main fields of District heating District heating Process heat Local heating Detached. application for industry networks family house,examples hospitals single settlements. steam hot buildings single,water hospitals big buildings. administration schools,buildings hotels small,commercial.
enterprises, Range of 5 1000 MWel 20 100 MWel 1 10 MWel 20 1000 kWel 5 15 kWel. Cogeneration 0 30 0 60 0 80 1 20 0 40 0 60 0 55 0 65 0 35 0 45. El efficiency 0 25 0 353 0 40 0 50 0 20 0 35 0 30 0 40 0 25 0 30. 0 30 0 404, Overall 0 455 0 85 0 555 0 85 0 75 0 85 0 85 0 90 0 85 0 90. efficiency, Advantages Waste heat Low investment High Small dimension compact. recovery at costs high temperature construction high overall. huge power cogeneration level process efficiency,stations index heat. Cogeneration index power production heat Assumption Only a very small amount of the. production produced heat is recovered Huge power, SCR remove nitrogen by urea stations are often built far away from the heat.
Back pressure turbine maximum heat consumers that is why in general only a small. decoupling part of the produced heat can be used,Bleeding turbines maximum heat decoupling. 1 2 COGENERATION PRINCIPLES,1 2 1 Heat engines, The following basic options of cogeneration are basically distinguished some newest. technologies are not referred herein,Cogeneration with steam turbine. They are operated by hard coal brown coal oil wood waste peat or nuclear fuel. Steam is the medium by which thermal energy is converted into mechanical. Cogeneration with gas turbine, Oil and gas are the only suitable fuels The working medium is the exhaust gas of. the combustion chamber,Cogeneration in combined cycle.
The high heat and oxygen content of the gas turbine exhaust gases is used in a. second process with a steam turbine,Cogeneration with reciprocating engine. The chemical bounded energy of natural gas or diesel for example is directly. transformed by combustion into mechanical energy, All the above technologies are able to produce both electrical and thermal energy. and are characterized as heat engines More specifically the heat engine is defined. as a device that converts heat energy into mechanical energy or more exactly a. system that operates continuously and only heat and work may pass across its. boundaries Moreover the operation of a heat engine can best be represented by a. thermodynamic cycle Some examples are the Otto Diesel Brayton Stirling and. Rankine cycles,1 2 2 Internal combustion engines, Among the most widely used and most efficient CHP prime movers are reciprocating. or internal combustion engines Several types of these engines are commercially. available but two designs are of most significance to stationary power applications. namely four cycle spark ignited Otto cycle and compression ignited diesel cycle. engines The essential mechanical parts of Otto cycle and diesel engines are the. same They both use a cylindrical combustion chamber in which a close fitting piston. travels the length of the cylinder, The piston is connected to a crankshaft that transforms the linear motion of the piston. within the cylinder into the crankshaft rotary motion Most engines have multiple. cylinders that power a single crankshaft Both Otto cycle and four stroke diesel. engines complete a power cycle in four strokes of the piston within the cylinder. Strokes include, 1 introduction of air or air fuel mixture into the cylinder.
2 compression with combustion of fuel, 3 acceleration of the piston by the force of combustion power stroke and. 4 expulsion of combustion products from the cylinder. The primary difference between Otto and diesel cycles is the method of fuel. combustion An Otto cycle uses a spark plug to ignite a pre mixed fuel air mixture. introduced to the cylinder A diesel engine compresses the air introduced in the. cylinder to a high pressure raising its temperature to the ignition temperature of the. fuel that is injected at high pressure,1 2 2 1 Otto cycle. Several engines may be approximated by an Otto cycle figure 1 2 such as petrol. engines and gas engines The Otto cycle is an ideal air standard cycle that consists. of four processes,x 1 to 2 Isentropic compression,x 2 to 3 Reversible constant volume heating. x 3 to 4 Isentropic expansion,x 4 to 1 Reversible constant volume cooling. Figure 1 2 P V diagram for an Otto cycle, The thermal efficiency of an Otto cycle with a perfect gas as working fluid is.
while it can be shown that the above relation can be reduced to the following one. where r V1 V2 is the compression ratio and n 1 is a constant depending on. the specific heat capacity,1 2 2 2 Diesel cycle, The Diesel cycle figure 1 3 is an ideal air standard cycle that also consists of four. x 1 to 2 Isentropic compression,x 2 to 3 Reversible constant pressure heating. x 3 to 4 Isentropic expansion,x 4 to 1 Reversible constant volume cooling. Figure 1 3 P V diagram for a Diesel cycle, By defining the compression ratio r as r V1 V2 and the cut off ratio as V3 V2. the thermal efficiency of a Diesel cycle with a perfect gas as working fluid is. 1 r n 1 1 r n 1 2, where n is a constant depending on specific heat capacity.

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