This document discusses thermodynamic cycles and steam power plants. It describes the Carnot, Otto, and Diesel cycles, outlining their key processes on P-V and T-S diagrams. It provides the basic equations and properties for each cycle. The document also lists the typical components of a steam power plant, including coal storage, coal handling, the boiler, air preheater, economizer, turbine, and generator.
The document discusses the idealized air standard diesel cycle that is used to analyze internal combustion engine processes. It describes how the actual open cycle is approximated as a closed cycle by assuming exhaust gases are recycled. It also outlines how the combustion process is replaced with constant pressure heat addition and other actual processes are approximated using ideal processes like constant pressure and isentropic. Finally, it provides the thermodynamic analysis of the six processes that make up the air standard diesel cycle and gives the equation to calculate the cycle's thermal efficiency.
George Brayton designed the first continuous combustion engine, known as the Brayton engine, in the 1860s. The Brayton engine introduced the Brayton cycle of continuous combustion that became the basis for gas turbine development. A Brayton-type engine consists of an air compressor, mixing chamber, and expander. The Brayton cycle uses four thermodynamic processes - two constant pressure and two reversible adiabatic processes - and is now used in gas turbines where compression and expansion occur via rotating machinery.
This presentation discusses the Rankine cycle, which is used in 90% of power plants worldwide. It introduces William Rankine, who helped develop thermodynamics. The presentation covers the ideal Rankine cycle and modifications like reheat and regeneration cycles that improve efficiency. Reheat cycles add a second turbine, while regeneration cycles use extracted steam to preheat feedwater, improving heat transfer and efficiency. The document aims to explain these Rankine cycle variations and their advantages over the basic cycle.
The document summarizes key concepts about thermodynamics cycles. It describes the processes that make up the Otto cycle used in spark-ignition engines, including isentropic compression, constant volume heat addition, isentropic expansion, and constant volume heat rejection. The thermal efficiency of the Otto cycle is defined. An example calculation illustrates determining temperatures, pressures, thermal efficiency, back work ratio, and mean effective pressure for an Otto cycle. The Diesel cycle used in compression ignition engines is also introduced.
Aircraft refrigeration system (air cooling system)Ripuranjan Singh
Aircraft air refrigeration systems are required due to heat transfer from many external and internal heat sources (like solar radiation and avionics) which increase the cabin air temperature. With the technological developments in high-speed passenger and jet aircraft's, the air refrigeration systems are proving to be most efficient, compact and simple. Various types of aircraft air refrigeration systems used these days are.
Simple air cooling system
Simple air evaporative cooling system
Boot strap air cooling system
Boot strap air evaporative cooling system
Reduced ambient air cooling system
Regenerative air cooling system
COMPRESSOR EFFICIENCY AND TURBINE EFFICIENCY.
Comparison of Various Air Cooling Systems used for Aircraft ON basis of dart
The document summarizes several thermodynamic cycles including the Otto, Diesel, Carnot, refrigeration, and Brayton cycles. For each cycle, it outlines the key processes and applications. The Otto cycle involves two isentropic and two constant volume processes and is used in spark ignition engines. The Diesel cycle uses constant pressure heat addition and has a higher efficiency than the Otto cycle. The Carnot cycle involves reversible, isothermal and adiabatic processes and sets the maximum possible efficiency. The refrigeration cycle uses vapor compression to transfer heat between regions. The Brayton cycle consists of adiabatic compression and expansion with isobaric heat transfer and is commonly used in gas turbine engines.
The document discusses various air standard cycles that are used to model internal combustion engine processes, including the Otto, Diesel, and dual cycles. It provides details on the assumptions and thermodynamic processes that define each cycle. The Otto cycle consists of four processes: constant-pressure intake, isentropic compression, constant-volume combustion, and isentropic expansion. The Diesel cycle models combustion as a constant-pressure process rather than constant volume. The dual cycle models combustion as both constant-volume and constant-pressure processes. Comparisons are made between the cycles in terms of their heat transfer and thermal efficiencies.
Combustion in an SI engine occurs in three stages:
1. The ignition lag stage is the delay between the spark and noticeable pressure rise from combustion. This allows the fuel-air mixture to heat up to its self-ignition temperature.
2. In the flame propagation stage, the flame front travels across the combustion chamber, releasing energy and increasing pressure.
3. The afterburning stage finishes combusting any remaining unburnt fuel-air mixture after the flame front passes.
The document discusses the idealized air standard diesel cycle that is used to analyze internal combustion engine processes. It describes how the actual open cycle is approximated as a closed cycle by assuming exhaust gases are recycled. It also outlines how the combustion process is replaced with constant pressure heat addition and other actual processes are approximated using ideal processes like constant pressure and isentropic. Finally, it provides the thermodynamic analysis of the six processes that make up the air standard diesel cycle and gives the equation to calculate the cycle's thermal efficiency.
George Brayton designed the first continuous combustion engine, known as the Brayton engine, in the 1860s. The Brayton engine introduced the Brayton cycle of continuous combustion that became the basis for gas turbine development. A Brayton-type engine consists of an air compressor, mixing chamber, and expander. The Brayton cycle uses four thermodynamic processes - two constant pressure and two reversible adiabatic processes - and is now used in gas turbines where compression and expansion occur via rotating machinery.
This presentation discusses the Rankine cycle, which is used in 90% of power plants worldwide. It introduces William Rankine, who helped develop thermodynamics. The presentation covers the ideal Rankine cycle and modifications like reheat and regeneration cycles that improve efficiency. Reheat cycles add a second turbine, while regeneration cycles use extracted steam to preheat feedwater, improving heat transfer and efficiency. The document aims to explain these Rankine cycle variations and their advantages over the basic cycle.
The document summarizes key concepts about thermodynamics cycles. It describes the processes that make up the Otto cycle used in spark-ignition engines, including isentropic compression, constant volume heat addition, isentropic expansion, and constant volume heat rejection. The thermal efficiency of the Otto cycle is defined. An example calculation illustrates determining temperatures, pressures, thermal efficiency, back work ratio, and mean effective pressure for an Otto cycle. The Diesel cycle used in compression ignition engines is also introduced.
Aircraft refrigeration system (air cooling system)Ripuranjan Singh
Aircraft air refrigeration systems are required due to heat transfer from many external and internal heat sources (like solar radiation and avionics) which increase the cabin air temperature. With the technological developments in high-speed passenger and jet aircraft's, the air refrigeration systems are proving to be most efficient, compact and simple. Various types of aircraft air refrigeration systems used these days are.
Simple air cooling system
Simple air evaporative cooling system
Boot strap air cooling system
Boot strap air evaporative cooling system
Reduced ambient air cooling system
Regenerative air cooling system
COMPRESSOR EFFICIENCY AND TURBINE EFFICIENCY.
Comparison of Various Air Cooling Systems used for Aircraft ON basis of dart
The document summarizes several thermodynamic cycles including the Otto, Diesel, Carnot, refrigeration, and Brayton cycles. For each cycle, it outlines the key processes and applications. The Otto cycle involves two isentropic and two constant volume processes and is used in spark ignition engines. The Diesel cycle uses constant pressure heat addition and has a higher efficiency than the Otto cycle. The Carnot cycle involves reversible, isothermal and adiabatic processes and sets the maximum possible efficiency. The refrigeration cycle uses vapor compression to transfer heat between regions. The Brayton cycle consists of adiabatic compression and expansion with isobaric heat transfer and is commonly used in gas turbine engines.
The document discusses various air standard cycles that are used to model internal combustion engine processes, including the Otto, Diesel, and dual cycles. It provides details on the assumptions and thermodynamic processes that define each cycle. The Otto cycle consists of four processes: constant-pressure intake, isentropic compression, constant-volume combustion, and isentropic expansion. The Diesel cycle models combustion as a constant-pressure process rather than constant volume. The dual cycle models combustion as both constant-volume and constant-pressure processes. Comparisons are made between the cycles in terms of their heat transfer and thermal efficiencies.
Combustion in an SI engine occurs in three stages:
1. The ignition lag stage is the delay between the spark and noticeable pressure rise from combustion. This allows the fuel-air mixture to heat up to its self-ignition temperature.
2. In the flame propagation stage, the flame front travels across the combustion chamber, releasing energy and increasing pressure.
3. The afterburning stage finishes combusting any remaining unburnt fuel-air mixture after the flame front passes.
The document discusses various factors that affect the efficiency of internal combustion engines such as specific heat, dissociation, premixed vs non-premixed fuel charges, and different types of losses in actual engine cycles compared to ideal cycles. It notes that the actual efficiency of a good engine is around 25% of the estimated efficiency from the ideal air standard cycle due to losses from factors like heat transfer, combustion, pumping, and blow-by. Fuel-air ratio can impact maximum power output due to chemical equilibrium losses. Variable specific heats can increase maximum pressure but decrease maximum temperature compared to constant specific heats.
The document provides information about gas turbine power plants including:
- The basic working principle of a gas turbine power plant which uses a gas turbine coupled to a compressor and combustion chamber.
- Gas turbines operate on the Brayton cycle, which involves compressing air, adding heat through combustion, expanding the gas, and rejecting heat.
- Key advantages of gas turbines include greater power density, high reliability, and less maintenance compared to steam turbines. Disadvantages include lower efficiency and higher noise levels.
- Major applications are aircraft propulsion and electric power generation. Numerical examples are provided to calculate the performance of ideal and actual Brayton cycles.
This document presents information on gas turbine cycles. It discusses open and closed cycle gas turbines, with open cycle directly discharging exhaust to the atmosphere and closed cycle recirculating working medium. It also describes how intercooling, reheating, and regeneration can increase the net work output of gas turbine cycles by reducing compressor work and increasing turbine work. A T-S diagram is included to illustrate an ideal gas turbine cycle with these modifications.
1. The document discusses gas turbine cycles with two shafts, where one turbine drives the compressor and the other provides power output. It describes regeneration using a heat exchanger to improve efficiency by heating the compressed air. Intercooling between compression stages and reheating are also discussed to reduce the work of compression. Examples are provided to calculate efficiency, power output, temperatures and pressures at different points in regenerative cycles with variations like intercooling.
The document summarizes the ideal Rankine cycle process. It describes 4 key processes:
1) Constant pressure heating of water to steam in the boiler.
2) Reversible, adiabatic expansion of steam in the turbine.
3) Reversible heat rejection during condensation of steam in the condenser.
4) Reversible, adiabatic compression of the liquid in the pump back to the boiler pressure.
It notes that real processes are irreversible with entropy increases due to friction and heat transfer, reducing turbine work and efficiency. Losses occur in the turbine, condenser, pump and via piping. Superheating improves efficiency but is limited by material temperatures.
This document summarizes the testing and performance of diesel and petrol engines. It describes the key components and operating principles of diesel and petrol engines. It then discusses various performance characteristics of internal combustion engines that are used to evaluate engine performance, such as brake thermal efficiency, indicated thermal efficiency, specific fuel consumption, mechanical efficiency, volumetric efficiency, air fuel ratio, and mean effective pressure. The performance of engines is tested by measuring fuel consumption, brake power, and specific power output using various types of dynamometers.
This document contains 6 exercises related to calculating the thermal efficiency of steam power plants operating on different Rankine cycle configurations including:
1) Ideal Rankine cycle
2) Ideal reheat Rankine cycle
3) Reheat Rankine cycle with specified turbine inlet/exit conditions
4) Regenerative Rankine cycle with one open feedwater heater
5) Reheat-regenerative cycle with one open feedwater heater, one closed feedwater heater, and one reheater.
The 6th exercise asks to determine the fractions of steam extracted from the turbine and the thermal efficiency for a plant operating on the reheat-regenerative cycle described in item 5 above.
A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled toa downstream turbine, and a combustion chamber in-between. Energy is added to the gas stream in the combustor, where fuel is mixed with air and ignited. In the high-pressure environment of the combustor, combustion of the fuel increases the temperature. The products of the combustion are forced into the turbine section
Visit https://www.topicsforseminar.com to Download
This document discusses various thermodynamic power cycles including:
- The Carnot cycle, which is the most efficient but impractical cycle.
- Rankine cycles, which are more practical vapor power cycles that use steam as the working fluid.
- Simple Rankine cycles involve heating water to steam then expanding it in a turbine before condensing it back to water.
- Rankine cycles with superheated steam, which increase efficiency by heating steam above its saturation temperature.
- The efficiencies of different cycles are calculated and compared in examples. Superheated steam cycles have higher efficiencies than simple Rankine cycles due to higher average temperatures.
Heat transfer from extended surfaces (or fins)tmuliya
This file contains slides on Heat Transfer from Extended Surfaces (FINS). The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India.
Contents: Governing differential eqn – different boundary conditions – temp. distribution and heat transfer rate for: infinitely long fin, fin with insulated end, fin losing heat from its end, and fin with specified temperatures at its ends – performance of fins - ‘fin efficiency’ and ‘fin effectiveness’ – fins of non-uniform cross-section- thermal resistance and total surface efficiency of fins – estimation of error in temperature measurement - Problems
This document provides an overview of boiler performance measurement parameters including equivalent evaporation. It defines equivalent evaporation as the amount of water evaporated per unit time using standard inlet/outlet conditions. A mathematical expression is derived and explained for equivalent evaporation. The document also introduces and explains the factor of evaporation parameter.
The document presents information on a bootstrap air cooling system suitable for aircraft. It consists of two heat exchangers, a secondary compressor driven by a turbine, and uses ram air and compression to cool and circulate air. Ambient air is compressed by the main aircraft compressor then cooled in an air cooler before further compression and cooling. It is then expanded through a turbine to provide cooled air to the aircraft cabin. Advantages are that air is readily available, non-toxic, and pressures are low. A limitation is that it requires aircraft flight for ram air cooling and is not suitable for ground use without an additional fan.
This document discusses the reversed Carnot cycle, which is used in Carnot refrigerators and heat pumps. It consists of four processes: 1) adiabatic compression, 2) isothermal compression, 3) adiabatic expansion, and 4) isothermal expansion. This cycle operates in the counterclockwise direction on a temperature-entropy diagram. It is the most efficient refrigeration cycle possible between two temperature levels, as it achieves the highest theoretical coefficient of performance. However, it cannot be practically implemented due to the different speeds required for the adiabatic and isothermal processes.
The dual cycle is an important part of I mechanical engineering.
here I have to try to derive some of the rules and important parts.
such as,
1.History
2.Comparison Between Otto, Diesel and Dual Cycle
3.Dual Combustion Engine
4.Characteristics
5.Parts Of Engine
6.Stroke
7.Sequence of Operations
8.Expression For Efficiency
9.Applications
10.Automobile
11.Generators/Aircrafts
12.Marine Engines
I hope this will help you to get all your required information plz like it and share it.
Connect with me on :
Youtube: Harshal Bhatt
Instagram: harshalbhatt_official
Twitter: HarshalBhatt318
Snapchat: harshalbhatt31
A gas turbine uses a gaseous working fluid to generate mechanical power that can power industrial devices. It has three main parts - an air compressor, combustion chamber, and turbine. The air is compressed in the compressor, mixed with fuel and ignited in the combustion chamber, and the hot gases spin the turbine to generate power. Some applications of gas turbines include aviation, power generation, and the oil and gas industry. The efficiency of gas turbines is typically 20-30% compared to 38-48% for steam power plants.
A detailed explanation about Rankine cycle or vapour power cycle for mechanical 2nd year students.Areas of uses of vapour power cycle or steam power cycle.
The document provides an overview of internal combustion engines. It discusses the basic classifications and cycles of internal combustion engines including two-stroke and four-stroke engines. It also covers the workings of spark ignition and compression ignition engines, as well as common engine components and systems such as carburetors and fuel injection systems. Key topics include the Otto, Diesel, and Carnot power cycles; combustion stages; valve timing diagrams; and scavenging, pre-ignition, detonation, lubrication, and emissions control.
The document discusses two-stroke and four-stroke internal combustion engines. It provides details on the working principles of two-stroke petrol and diesel engines. A two-stroke engine completes the processes of intake, compression, combustion and exhaust in two strokes of the piston rather than four strokes as in a four-stroke engine. This allows a two-stroke engine to produce power during every revolution of the crankshaft.
This document defines important terms related to thermodynamic air cycles such as cylinder bore, stroke length, clearance volume, and compression ratio. It then summarizes several common thermodynamic cycles including Carnot, Otto, and Diesel cycles. For the Carnot cycle, it shows the calculations for work done and efficiency. For the Otto cycle, it outlines the four stages and provides equations to calculate efficiency based on compression ratio and temperature changes between stages.
- The Carnot cycle consists of four processes: two reversible isothermal heat transfer processes and two reversible adiabatic processes.
- The efficiency of the Carnot cycle depends only on the source and sink temperatures, irrespective of the working fluid. Maximum efficiency is achieved with highest source temperature and lowest sink temperature.
- The Carnot COP is the maximum theoretical COP between two temperatures for refrigeration or heat pump cycles. No real system can exceed the Carnot COP.
The document discusses various factors that affect the efficiency of internal combustion engines such as specific heat, dissociation, premixed vs non-premixed fuel charges, and different types of losses in actual engine cycles compared to ideal cycles. It notes that the actual efficiency of a good engine is around 25% of the estimated efficiency from the ideal air standard cycle due to losses from factors like heat transfer, combustion, pumping, and blow-by. Fuel-air ratio can impact maximum power output due to chemical equilibrium losses. Variable specific heats can increase maximum pressure but decrease maximum temperature compared to constant specific heats.
The document provides information about gas turbine power plants including:
- The basic working principle of a gas turbine power plant which uses a gas turbine coupled to a compressor and combustion chamber.
- Gas turbines operate on the Brayton cycle, which involves compressing air, adding heat through combustion, expanding the gas, and rejecting heat.
- Key advantages of gas turbines include greater power density, high reliability, and less maintenance compared to steam turbines. Disadvantages include lower efficiency and higher noise levels.
- Major applications are aircraft propulsion and electric power generation. Numerical examples are provided to calculate the performance of ideal and actual Brayton cycles.
This document presents information on gas turbine cycles. It discusses open and closed cycle gas turbines, with open cycle directly discharging exhaust to the atmosphere and closed cycle recirculating working medium. It also describes how intercooling, reheating, and regeneration can increase the net work output of gas turbine cycles by reducing compressor work and increasing turbine work. A T-S diagram is included to illustrate an ideal gas turbine cycle with these modifications.
1. The document discusses gas turbine cycles with two shafts, where one turbine drives the compressor and the other provides power output. It describes regeneration using a heat exchanger to improve efficiency by heating the compressed air. Intercooling between compression stages and reheating are also discussed to reduce the work of compression. Examples are provided to calculate efficiency, power output, temperatures and pressures at different points in regenerative cycles with variations like intercooling.
The document summarizes the ideal Rankine cycle process. It describes 4 key processes:
1) Constant pressure heating of water to steam in the boiler.
2) Reversible, adiabatic expansion of steam in the turbine.
3) Reversible heat rejection during condensation of steam in the condenser.
4) Reversible, adiabatic compression of the liquid in the pump back to the boiler pressure.
It notes that real processes are irreversible with entropy increases due to friction and heat transfer, reducing turbine work and efficiency. Losses occur in the turbine, condenser, pump and via piping. Superheating improves efficiency but is limited by material temperatures.
This document summarizes the testing and performance of diesel and petrol engines. It describes the key components and operating principles of diesel and petrol engines. It then discusses various performance characteristics of internal combustion engines that are used to evaluate engine performance, such as brake thermal efficiency, indicated thermal efficiency, specific fuel consumption, mechanical efficiency, volumetric efficiency, air fuel ratio, and mean effective pressure. The performance of engines is tested by measuring fuel consumption, brake power, and specific power output using various types of dynamometers.
This document contains 6 exercises related to calculating the thermal efficiency of steam power plants operating on different Rankine cycle configurations including:
1) Ideal Rankine cycle
2) Ideal reheat Rankine cycle
3) Reheat Rankine cycle with specified turbine inlet/exit conditions
4) Regenerative Rankine cycle with one open feedwater heater
5) Reheat-regenerative cycle with one open feedwater heater, one closed feedwater heater, and one reheater.
The 6th exercise asks to determine the fractions of steam extracted from the turbine and the thermal efficiency for a plant operating on the reheat-regenerative cycle described in item 5 above.
A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled toa downstream turbine, and a combustion chamber in-between. Energy is added to the gas stream in the combustor, where fuel is mixed with air and ignited. In the high-pressure environment of the combustor, combustion of the fuel increases the temperature. The products of the combustion are forced into the turbine section
Visit https://www.topicsforseminar.com to Download
This document discusses various thermodynamic power cycles including:
- The Carnot cycle, which is the most efficient but impractical cycle.
- Rankine cycles, which are more practical vapor power cycles that use steam as the working fluid.
- Simple Rankine cycles involve heating water to steam then expanding it in a turbine before condensing it back to water.
- Rankine cycles with superheated steam, which increase efficiency by heating steam above its saturation temperature.
- The efficiencies of different cycles are calculated and compared in examples. Superheated steam cycles have higher efficiencies than simple Rankine cycles due to higher average temperatures.
Heat transfer from extended surfaces (or fins)tmuliya
This file contains slides on Heat Transfer from Extended Surfaces (FINS). The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India.
Contents: Governing differential eqn – different boundary conditions – temp. distribution and heat transfer rate for: infinitely long fin, fin with insulated end, fin losing heat from its end, and fin with specified temperatures at its ends – performance of fins - ‘fin efficiency’ and ‘fin effectiveness’ – fins of non-uniform cross-section- thermal resistance and total surface efficiency of fins – estimation of error in temperature measurement - Problems
This document provides an overview of boiler performance measurement parameters including equivalent evaporation. It defines equivalent evaporation as the amount of water evaporated per unit time using standard inlet/outlet conditions. A mathematical expression is derived and explained for equivalent evaporation. The document also introduces and explains the factor of evaporation parameter.
The document presents information on a bootstrap air cooling system suitable for aircraft. It consists of two heat exchangers, a secondary compressor driven by a turbine, and uses ram air and compression to cool and circulate air. Ambient air is compressed by the main aircraft compressor then cooled in an air cooler before further compression and cooling. It is then expanded through a turbine to provide cooled air to the aircraft cabin. Advantages are that air is readily available, non-toxic, and pressures are low. A limitation is that it requires aircraft flight for ram air cooling and is not suitable for ground use without an additional fan.
This document discusses the reversed Carnot cycle, which is used in Carnot refrigerators and heat pumps. It consists of four processes: 1) adiabatic compression, 2) isothermal compression, 3) adiabatic expansion, and 4) isothermal expansion. This cycle operates in the counterclockwise direction on a temperature-entropy diagram. It is the most efficient refrigeration cycle possible between two temperature levels, as it achieves the highest theoretical coefficient of performance. However, it cannot be practically implemented due to the different speeds required for the adiabatic and isothermal processes.
The dual cycle is an important part of I mechanical engineering.
here I have to try to derive some of the rules and important parts.
such as,
1.History
2.Comparison Between Otto, Diesel and Dual Cycle
3.Dual Combustion Engine
4.Characteristics
5.Parts Of Engine
6.Stroke
7.Sequence of Operations
8.Expression For Efficiency
9.Applications
10.Automobile
11.Generators/Aircrafts
12.Marine Engines
I hope this will help you to get all your required information plz like it and share it.
Connect with me on :
Youtube: Harshal Bhatt
Instagram: harshalbhatt_official
Twitter: HarshalBhatt318
Snapchat: harshalbhatt31
A gas turbine uses a gaseous working fluid to generate mechanical power that can power industrial devices. It has three main parts - an air compressor, combustion chamber, and turbine. The air is compressed in the compressor, mixed with fuel and ignited in the combustion chamber, and the hot gases spin the turbine to generate power. Some applications of gas turbines include aviation, power generation, and the oil and gas industry. The efficiency of gas turbines is typically 20-30% compared to 38-48% for steam power plants.
A detailed explanation about Rankine cycle or vapour power cycle for mechanical 2nd year students.Areas of uses of vapour power cycle or steam power cycle.
The document provides an overview of internal combustion engines. It discusses the basic classifications and cycles of internal combustion engines including two-stroke and four-stroke engines. It also covers the workings of spark ignition and compression ignition engines, as well as common engine components and systems such as carburetors and fuel injection systems. Key topics include the Otto, Diesel, and Carnot power cycles; combustion stages; valve timing diagrams; and scavenging, pre-ignition, detonation, lubrication, and emissions control.
The document discusses two-stroke and four-stroke internal combustion engines. It provides details on the working principles of two-stroke petrol and diesel engines. A two-stroke engine completes the processes of intake, compression, combustion and exhaust in two strokes of the piston rather than four strokes as in a four-stroke engine. This allows a two-stroke engine to produce power during every revolution of the crankshaft.
This document defines important terms related to thermodynamic air cycles such as cylinder bore, stroke length, clearance volume, and compression ratio. It then summarizes several common thermodynamic cycles including Carnot, Otto, and Diesel cycles. For the Carnot cycle, it shows the calculations for work done and efficiency. For the Otto cycle, it outlines the four stages and provides equations to calculate efficiency based on compression ratio and temperature changes between stages.
- The Carnot cycle consists of four processes: two reversible isothermal heat transfer processes and two reversible adiabatic processes.
- The efficiency of the Carnot cycle depends only on the source and sink temperatures, irrespective of the working fluid. Maximum efficiency is achieved with highest source temperature and lowest sink temperature.
- The Carnot COP is the maximum theoretical COP between two temperatures for refrigeration or heat pump cycles. No real system can exceed the Carnot COP.
This chapter discusses gas power cycles where the working fluid remains a gas throughout. It introduces the ideal Carnot cycle and air-standard assumptions used to model real cycles. The chapter analyzes the Otto, Diesel, Stirling, Ericsson and Brayton cycles. It discusses the use of regeneration, intercooling and reheating to improve the Brayton cycle efficiency. The chapter also covers jet propulsion cycles and modifications like turbofans. Real cycles deviate from ideal cycles due to irreversibilities. The chapter provides examples to calculate cycle parameters and efficiencies.
The document provides an overview of different types of reciprocating engine cycles, including definitions of key terms, equations, and efficiency calculations. It describes the ideal Otto, Diesel, and dual combustion cycles. It includes equations to calculate efficiency, temperatures, pressures, work output, and mean effective pressure. It concludes with sample problems to calculate values for each cycle type.
GAS POWER CYCLES PRESENTATION FOR STUDENT UNIVERSITYssuser5a6db81
This document summarizes the key concepts and equations related to gas power cycles, including ideal cycles like Otto, Diesel, and Brayton cycles that are used in internal combustion engines. It discusses the assumptions and processes involved in each cycle. It also covers concepts like regeneration, intercooling, and reheat that are used to improve upon ideal cycles. The document provides definitions of important terms and examples of applying the cycle equations.
APPLIED THERMODYNAMICS 18ME42 Module 02 question no 3a 3b & 4a-4bTHANMAY JS
Module 02: Gas power Cycles & Jet Propulsion
Contents
Introduction to Gas Turbine
Types of Gas Turbines
Gas turbine (Brayton) cycle; Description, Types and analysis.
Gas turbine (Actual Brayton) cycle; description and analysis.
Regenerative, Inter-cooling and reheating in gas turbine cycles.
Introduction to Jet Propulsion cycles.
Problems on Brayton cycle
Problems on Actual Brayton cycle
The document provides information on several thermodynamic cycles used in power plants and engines, including:
1) The Carnot, Stirling, Ericsson, Brayton, Rankine, and Otto cycles. Equations for calculating efficiency are provided for some cycles.
2) Diagrams show the pressure-volume or temperature-entropy processes involved in each cycle. The Carnot cycle involves two isothermal and two adiabatic processes. The Stirling cycle has four processes: two isothermal and two isochoric.
3) The Rankine cycle closely describes the steam power cycle. It involves isobaric heating of liquid to steam, isentropic expansion in a turbine, isobar
- The cycle has intercooling, reheat, and regeneration. Air enters at 1 bar and 300 K.
- It undergoes two-stage compression with intercooling between stages. Hot gases from the turbine drive the regenerator before exiting.
- Additional fuel is burned in the reheat combustor between the high and low pressure turbines to increase total work output.
- The cycle aims to maximize performance by incorporating multiple advanced features like intercooling, reheat, and regeneration.
The document discusses Nicolas Carnot and the Carnot engine. It describes how Carnot discovered that a steam engine transfers heat from a warm reservoir to a cool one, using some of the heat to produce work. The greater the temperature difference between the reservoirs, the more efficient the engine. It then discusses the ideal Carnot cycle and the four processes involved: isothermal expansion, adiabatic expansion, isothermal compression, and adiabatic compression. The efficiency of a Carnot engine depends only on the temperatures of the heat reservoirs and is maximum when there is the greatest difference between these temperatures.
Simple description about gas turbine. Where you are going to know about its classification,advantages and disadvantages also.Here also you can find-out where it is actually usages.
1. The document is a lab report submitted by Muhammad Awais about gas turbines. It discusses the introduction, working principle, types, cycles and thermal efficiency of gas turbines.
2. The working principle of gas turbines is the Brayton cycle, which has four processes - intake, compression, combustion and exhaust. The types discussed include jet engines, aeroderivative gas turbines, industrial gas turbines and microturbines.
3. The two cycles discussed are the open cycle and closed cycle. The document also examines improvements like regeneration, reheating and intercooling processes and their effects on efficiency.
The document provides an introduction to heat engines and cycle analysis. It discusses how heat engines work by receiving heat from a high-temperature source, converting some of it to work, and rejecting the rest to a low-temperature sink. The Carnot cycle and engine are described as the most efficient theoretical cycle, involving reversible isothermal and adiabatic processes. The Carnot refrigerator operating on the reversed cycle is also introduced. Key concepts covered include thermal efficiency, the impossibility of a 100% efficient engine or workless refrigerator per the second law of thermodynamics, and the coefficients of performance for heat engines and refrigerators.
The document provides information about gas turbine power plants. It discusses that gas turbines were invented in 1930 and are now commonly used for aircraft propulsion and power generation. A gas turbine works by compressing air, mixing it with fuel for combustion, and using the hot gases to power a turbine which drives both the compressor and a generator. The key components of a gas turbine are the compressor, combustion chamber, and turbine. The document also outlines the basic thermodynamic Brayton cycle that gas turbines are based on and discusses configurations like regenerative cycles, intercooling, and reheat to improve efficiency.
The document discusses closed cycle gas power plants. It begins with an introduction that defines closed cycle systems as those where a working gas like air is compressed, heated, expanded through a turbine to produce power, cooled, and recycled through the system. It then discusses the main components of closed cycle plants including compressors, combustion chambers, turbines, generators, and intercoolers. The working principle involves isentropic compression, constant pressure heating, isentropic expansion in the turbine, and constant pressure cooling. Key improvements discussed include higher operating temperatures through improved materials and cooling, and cycle modifications like regeneration to increase efficiency. Advantages are high efficiency while disadvantages include greater complexity versus open cycle plants.
Gas Power Cycles in Chemical Engineering Thermodynamics.pptHafizMudaserAhmad
This document describes several gas power cycles including ideal cycles like the Otto cycle, Diesel cycle, and Brayton cycle as well as actual engine cycles. It provides details on the assumptions and processes of each ideal cycle. The Otto cycle involves four internally reversible processes including isentropic compression and expansion with constant-volume heat addition and rejection. The Diesel cycle similarly involves isentropic compression and expansion but with constant-pressure rather than constant-volume heat addition. The Brayton cycle models gas turbine engines with isentropic compression and expansion and constant-pressure heat transfer. Regeneration and intercooling are discussed as ways to improve upon actual engine cycles.
This document describes several gas power cycles including ideal cycles like the Otto cycle, Diesel cycle, and Brayton cycle as well as actual engine cycles. It provides details on the assumptions and processes of each ideal cycle. The Otto cycle involves four internally reversible processes: isentropic compression, constant-volume heat addition, isentropic expansion, and constant-volume heat rejection. The Diesel cycle also involves four internally reversible processes but with compression ignition. The Brayton cycle is typically used in gas turbines and involves isentropic compression, constant-pressure heat addition, isentropic expansion, and constant-pressure heat rejection. Regeneration and intercooling can improve the efficiency of actual cycles.
This document provides definitions and key concepts related to applied thermodynamics and heat engines. It defines a heat engine as a device that converts heat energy into mechanical work. It then lists common thermodynamic equations including those for absolute pressure, temperature, heat transfer, gas laws, and the first law of thermodynamics. The document also summarizes the laws of thermodynamics, common thermodynamic cycles, and components and systems of internal combustion engines.
This document describes a project to optimize the performance of a steam turbine power plant using the Rankine cycle. Five different Rankine cycles are analyzed: 1) the ideal Rankine cycle, 2) the ideal Rankine cycle with reheat, 3) the ideal Rankine cycle with one open feedwater heater, 4) with two open feedwater heaters, and 5) with four open feedwater heaters. Sample calculations are shown for each cycle configuration to determine the thermal efficiency. The document also discusses cost effectiveness calculations to determine the most optimal design for the steam turbine.
This document summarizes key concepts about heat engines:
1. Heat engines receive heat from a high-temperature source, convert some of that heat to work (e.g. rotating shaft), and reject the remaining waste heat to a low-temperature sink.
2. The Carnot cycle represents the theoretical maximum efficiency possible for a heat engine. The Carnot efficiency depends only on the high and low temperatures.
3. Practical heat engines like the Rankine, Otto, and Diesel cycles have lower efficiencies than the Carnot cycle but can extract useful work. Combined cycle gas turbines approach Carnot efficiencies.
This document summarizes different types of heat engines. It describes elementary heat engines which use heat transfer and work to operate. Heat engines are classified as external or internal combustion engines based on where fuel combustion occurs. The key components of heat engines are also outlined, including the heat source, heat sink, working fluid, expander and compressor. Specific heat engine cycles like the Carnot, Rankine, Otto and Diesel cycles are then explained in detail through diagrams and thermodynamic process descriptions. The efficiencies of different cycles are also derived based on heat transfer and work.
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2. 2nd law of Thermodynamics
1st law of Thermodynamics
Consists of a series of thermodynamic processes, which take place in a specific order, and the initial conditions are
restored at the end of the processes.
Thermodynamic cycle
Classes of Thermodynamic Cycle:
1. Power cycle
-Convert some heat input into a mechanical work output
2. Heat pump cycles
-transfer heat from low to high temperatures by using mechanical work as the input
3. Class of cycle
/Working Substance
POWER CYCLE HEAT PUMP CYCLE
Ideal Gas - Carnot cycle
- Brayton cycle
- Otto cycle
- Diesel cycle
- Stirling cycle
- Ericson cycle
- Regenerative gas turbine cycle
- Intercooling, reheat regenerative
gas cycles
- Combined brayton-rankine cycle
- Reversed Carnot cycle
- Gas refrigeration cycle
Pure Substance - Rankine cycle
- Reheat cycle
- Supercritical rankine cycle
- Regenerative cycle
- Vapor refrigeration cycle
- Multistage vapor refrigeration
cycle
- Absorption refrigeration cycle
- Heat pump
4. Carnot Cycle: Ideal Power Thermodynamic Cycle
Is the most efficient thermodynamics cycle
between a high temperature reservoir and a
low temperature reservoir
An Ideal cycle that uses reversible processes
to form its cycle operation
1-2 Adiabatic Reversible compression. The completely
insulated cylinder allows no heat transfer during this
reversible process.
2-3 Isothermal Expansion. Heat is transferred reversibly
from the high temperature reservoir at the constant
temperature TH. The piston in the cylinder is withdrawn
and the volume increases.
3-4 Adiabatic Reversible Expansion. The cylinder is
completely insulated so that no heat transfer occurs
during this reversible process. The piston in the cylinder
continues to be withdrawn and the volume increasing.
4-1 Isothermal Compression. Heat is transferred
reversibly to the low temperature reservoir at the
constant temperature The piston continues to compress
the working substance until the original volume,
temperature, and pressure are reached, thereby
completing the cycle.
Carnot Cycle Processes
5. A. 𝑄𝐴 = heat added = 𝑇2 (𝑆4 - 𝑆1)
B. 𝑄𝑅 = heat rejected = 𝑇1 (𝑆4 - 𝑆1)
C. W = net work output = 𝑄𝐴 - 𝑄𝑅
W = (𝑇2 - 𝑇1) (𝑆4 - 𝑆1)
D. Change in entropy
ΔS =
𝑄𝐴
𝑇2
=
𝑄𝑅
𝑇1
=
𝑊
𝑇2−𝑇1
E. Cycle Efficiency
e =
𝑊
𝑄𝐴
=
𝑄𝐴−𝑄𝑅
𝑄𝐴
=
𝑊
𝑊+𝑄𝑅
e =
𝑇2−𝑇1
𝑇2
= 1 −
𝑇1
𝑇2
= 1 −
𝑇𝐿
𝑇𝐻
F. Mean Effective Pressure, Pm
𝑃𝑚 =
𝑊
𝑉𝐷
where: 𝑉𝐷 = 𝑉1 - 𝑉2
Properties of Carnot Cycle
Carnot Cycle: T-S diagram
Isentropic expansion and compression process
Isothermal heat addition and rejection process
6. Learning Exercises
1. A carnot engine requires 35 KJ/sec from the hot source. The engine produces 15kw of power and
temperature of the sink is 26 degree Celsius. What is the temperature of the hot source? Ans. 250.5 ˚ C
2. The maximum thermal efficiency possible for a power cycle operating between 1200 ˚F and 225 ˚F
is_____? Ans. 58.7%
3. A carnot engine operating on air accepts 50KJ/Kg of heat and rejects 20KJ/Kg. Calculate the high and low
reservoir temperature if the maximum specific volume is 10m^3/kg and the pressure after isothermal
expansion is 200Kpa. ans. 432.2 and 9.1 ˚ C
4. A Carnot engine receives 130Btu of heat from a hot reservoir at 700 ˚F and rejects 49Btu of heat.
Calculate the temperature of the cold reservoir. Ans. -22.77 ˚F
5. A carnot engine operates between two temperature reservoirs maintained at 200 ˚C and 20˚ C,
respectively. If the desired output of the engine is 15KW, determine the heat transfer from the high
temperature reservoir and heat transfer to the low-temperature reservoirs. Ans. 39.41KW, 24.41KW
6. A carnot heat engine produces 10Hp by transferring energy between two reservoirs at 40 ˚ F and 212 ˚ F.
Calculate the rate of heat transfer from the high temperature reservoir. Ans. 1656.56 Btu/min
7. Internal Combustion Engine
Is a heat engine which converts the heat energy released by the
combustion of the fuel inside the engine cylinder, into mechanical work.
Classification of I.C. Engines
1. Nature of thermodynamic cycles as:
1. Otto cycle engine
2. Diesel cycle engine
3. Dual combustion cycle engine
2. Type of the fuel used:
1. Gas engine
2. Diesel engine.
3. Bi-fuel engine
3. Number of strokes as:
1. Four stroke engine
2. Two stroke engine
4. Method of ignition as:
1. Spark ignition engine, known as SI engine
2. Compression ignition engine, known as C.I. engine
5. Number of cylinder as:
1. Single cylinder engine
2. Multi cylinder engine
6. Position of the cylinder as:
1. Horizontal engine
2. Vertical engine.
3. Vee engine
4. In-line engine.
5. Opposed cylinder engine
7. Method of cooling as:
1. Air cooled engine
2. Water cooled engine
8. is a spark ignition type engine
two constant volume and two isentropic process
heat is transferred during the two isentropic (constant volume) process
maximum temperature occur after combustion or before expansion
if compression ratio increases, it’s cycle efficiency will increase
cycle efficiency depends on compression ratio and it’s specific heat ratio
typical compression ratio is 8.0
P-V and T-S
DIAGRAM
Otto Cycle
10. A. 𝑸𝑨 = heat added = m𝑐𝑉 (𝑇3 - 𝑇2)
B. 𝑸𝑹 = heat rejected = m𝑐𝑉 (𝑇4 - 𝑇1)
C. W = work = 𝑄𝐴 - 𝑄𝑅
D. e = Cycle Efficiency
e =
𝑊
𝑄𝐴
=
𝑄𝐴−𝑄𝑅
𝑄𝐴
=
𝑊
𝑊+𝑄𝑅
=
(𝑇3−𝑇2) − (𝑇4−𝑇1)
𝑇3−𝑇2
e =1 -
1
𝑟𝐾
𝐾−1 = 1 -
1
𝑟𝑃
𝐾−1
𝐾
= 1 -
𝑇1
𝑇2
E. 𝑟𝐾 =
𝑉1
𝑉2
=
1+𝐶
𝐶
= compression ratio where c- clearance volume
F. 𝑃𝑚 =
𝑊
𝑉𝐷
=
𝑊
𝑉1−𝑉2
where: 𝑉1 =
𝑚𝑅𝑇1
𝑃1
𝑃3 = maximum pressure
Formulas: Otto Cycle
11. Learning Exercise:
1. An otto engine has clearance volume of 7%. It produces 300Kw power. What is the
amount of heat rejected in Kw? Ans. 152KW
2. In an air standard Otto Cycle, the clearance volume is 18% of the displacement
volume. Find the compression ratio and thermal efficiency. Ans. 6.556, 53%
3. An otto cycle has an initial condition of 100Kpa and 30 ˚C . The compression ratio is 10
and the maximum temperature is 1400 ˚C. Find the cycle mean effective pressure per
kg of air. Ans. 502.83Kpa
4. An engine operates on the air standard Otto cycle. The cycle work is 900KJ/Kg, the
maximum cycle temperature is 3000˚C and the temperature at the end of isentropic
compression is 600 ˚C. Determine the engines compression ratio. Ans. 6.388
5. An Otto cycle has an efficiency of 54%. If heat added is 400KJ, Find the work done.
Ans. 216KJ
12. is a compression-ignition type of engine
two isentropic, one constant pressure and one constant volume process
3. Diesel Cycle
P-V and T-S
DIAGRAM
14. A. 𝑸𝑨 = heat added = m𝑐𝑃 (𝑇3 - 𝑇2)
B. 𝑸𝑹 = heat rejected = m𝑐𝑉 (𝑇4 - 𝑇1)
C. W = work = 𝑄𝐴 - 𝑄𝑅
D. e = Cycle Efficiency
e =
𝑊
𝑄𝐴
=
𝑄𝐴−𝑄𝑅
𝑄𝐴
=
𝑊
𝑊+𝑄𝑅
=
(𝑇3−𝑇2) − (𝑇4−𝑇1)
𝑇3−𝑇2
e =1 -
1
𝑟𝐾
𝐾−1
𝑟𝑐
𝐾−1
𝐾∙ 𝑟𝑐−1
E. 𝑟𝐾 =
𝑉1
𝑉2
=
1+𝐶
𝐶
= compression ratio where c- clearance volume
F. 𝑃𝑚 =
𝑊
𝑉𝐷
=
𝑊
𝑉1−𝑉2
where: 𝑉1 =
𝑚𝑅𝑇1
𝑃1
𝑃2= 𝑃3 = maximum pressure
Formulas: Diesel Cycle
𝑟𝐾 = compression ratio =
𝑉1
𝑉2
𝑟𝑐 = Cut-off ratio =
𝑇3
𝑇2
=
𝑉3
𝑉2
𝑟𝑒 = Expansion ratio =
𝑉4
𝑉3
𝑟𝐾 = 𝑟𝑐 ∙ 𝑟𝑒
𝑉3 - 𝑉2 = Volume of fuel injected
15. Example:
• A diesel cycle has a compression ratio of 6 and cut off ratio of 2. If heat added is 1500KJ,
Find the heat rejected. Ans. 857.60KJ
• In an air standard diesel cycle, compression starts at 100Kpa and 300 ˚K. The compression
ratio is 12 and the maximum cycle temperature is 2000 ˚K. Determine the cycle efficiency.
Ans. 54.22%
• A diesel cycle has a compression ratio of 8 and initial temperature of 34 ˚C. If the
maximum temperature of the cycle is 2000 ˚K, find the Heat rejected. 726.3KJ/Kg
• A diesel cycle has a cycle efficiency of 58%. If heat added is 1600KJ/Kg, Find the work. Ans.
928 KJ/Kg
• A diesel has a compression ratio of 8 and cut off ratio of 2.5. Find the cycle efficiency. Ans.
45.97 %
17. Usual Component of Steam Power Plant
1. Coal Storage:
It is the place where coal is stored which can be utilised when required.
2. Coal Handling:
Here the coal is converted into the pulverised form before feeding to the furnace. A proper system is
designed to transport the pulverised coal to the boiler furnace.
3. Boiler:
It converts the water into high pressure steam. It contains the furnace inside or outside the boiler shell.
The combustion of coal takes place in the furnace.
4. Air-preheater:
It is used to pre-heat the air before entering into the boiler furnace. The pre heating of air helps in the
burning of fuel to a greater extent. It takes the heat from the burnt gases from the furnace to heat the
air from the atmosphere.
5. Economiser:
As its name indicates it economises the working of the boiler. It heats the feed water to a specified
temperature before it enters into the boiler drum. It takes the heat from the burnt gases from the
furnace to do so.
6. Turbine:
It is the mechanical device which converts the kinetic energy of the steam to the mechanical energy.
18. 7. Generator:
It is coupled with the turbine rotor and converts the mechanical energy of the turbine to the
electrical energy.
8. Ash Storage:
It is used to store the ash after the burning of the coal.
9. Dust Collector:
It collects the dust particle from the burnt gases before it is released to the chimney.
10. Condenser:
It condensate the steam that leaves out turbine. It converts the low pressure steam to water. It is
attached to the cooling tower.
11. Cooling Tower:
It is a tower which contains cold water. Cold water is circulates to the condenser for the cooling of
the residual steam from the turbine.
12. Chimney:
It is used to release the hot burnt gases or smoke from the furnace to the environment at
appropriate height. The height of the tower is very high such that it can easily throw the smoke and
exhaust gases at the appropriate height. And it cannot affect the population living near the steam
power plant.
13. Feed Water Pump:
It is used to transport the feed water to the boiler.
19. Rankine Cycle
is the fundamental operating cycle of all power plants where an operating fluid is continuously evaporated and
condensed.
•1-2 Isentropic Expansion. The vapor is expanded in the turbine, thus
producing work which may be converted to electricity. In practice, the
expansion is limited by the temperature of the cooling medium and by the
erosion of the turbine blades by liquid entrainment in the vapor stream as
the process moves further into the two-phase region. Exit vapor qualities
should be greater than 90%.
•2-3 Isobaric Heat Rejection. The vapor-liquid mixture leaving the turbine
is condensed at low pressure, usually in a surface condenser using
cooling water. In well designed and maintained condensers, the pressure
of the vapor is well below atmospheric pressure, approaching the
saturation pressure of the operating fluid at the cooling water temperature.
•3-4 Isentropic Compression. The pressure of the condensate is raised
in the feed pump. Because of the low specific volume of liquids, the pump
work is relatively small and often neglected in thermodynamic
calculations.
•4-1 Isobaric Heat Transfer. High pressure liquid enters the boiler from
the feed pump and is heated to the saturation temperature. Further
addition of energy causes evaporation of the liquid until it is fully
converted to saturated steam.
Processes
20. A. Heat added to the boiler
𝑞𝐴 = ℎ1 − ℎ4 , KJ/Kg
𝑄𝐴 =m(ℎ1 − ℎ4), KW
where ℎ1 = ℎ𝑔 @ given boiler pressure or temperature
B. Heat rejected from the condenser
𝑞𝑅 = ℎ2 − ℎ3, KJ/Kg
𝑄𝑅 =m(ℎ2 − ℎ3), KW
where ℎ3 = ℎ𝑓 @ given condenser pressure or temperature
C. Turbine Work
𝑤𝑇 = ℎ1 − ℎ2, KJ/Kg
𝑊𝑇 =m( ℎ1 − ℎ2), KW
Quality and Enthalpy after Turbine Expansion:
𝑆1 = 𝑆2 = 𝑆𝑓 + 𝑥𝑆𝑓𝑔 x =
𝑆2−𝑆𝑓
𝑆𝑓𝑔
ℎ2 = ℎ𝑓 + 𝑥ℎ𝑓𝑔
where: 𝑆𝑓, 𝑆𝑓𝑔, ℎ𝑓, ℎ𝑓𝑔 saturated properties @ given
condenser pressure or temperature
Properties of Rankine Cycle
D. Pump Work
𝑤𝑃 = ℎ4 − ℎ3, KJ/Kg
𝑊𝑃 =m( ℎ4 − ℎ3), KW
Enthalpy after compression:
ℎ4 = 𝑣3(𝑃4 − 𝑃3) + ℎ3, KW
where: 𝑃4 = Boiler Pressure
𝑃3 = Condenser Pressure
𝑣3=𝑣𝑓 @ given condenser pressure or
temperature
Pump Efficiency:
𝑒𝑝 =
𝑊𝑝
𝑊𝑖
E. Cycle Efficiency
e =
𝑇𝑢𝑟𝑏𝑖𝑛𝑒 𝑤𝑜𝑟𝑘−𝑃𝑢𝑚𝑝 𝑤𝑜𝑟𝑘
𝐻𝑒𝑎𝑡 𝐴𝑑𝑑𝑒𝑑
=
𝑊𝑡−𝑊𝑝
𝑄𝐴
=
𝑄𝐴−𝑄𝑅
𝑄𝐴
F. Heat Carried by Cooling Water
Heat receive by cooling water = Heat reject by condenser
𝑄𝑊 = 𝑄𝑅
𝑚𝑤 cp 𝑡2 − 𝑡1 = 𝑚𝑠 (ℎ2 − ℎ3)
𝑚𝑤 =
𝑚𝑠 (ℎ2−ℎ3)
𝑐𝑝 𝑡2−𝑡1
, kg
21. Learning Exercises
1. In a rankine cycle, steam enters the turbine saturated at 2.5 Mpa and
condenser at 50Kpa. What is the thermal efficiency of the cycle? Ans. 25.55%
2. In a rankine cycle, the steam throttle condition is 4.10 Mpa and 440 ˚ C. If
turbine exhaust is 0.105Mpa, determine: a) Heat added in the
boiler(2878.29KJ/Kg), b) Work of the turbine(797.16KJ/Kg), c)Pump
Work(4.172KJ/Kg), d)System Net Work(792.99KJ/Kg), e)Thermal efficiency of
the cycle(27.55%).
3. A steam power plant is proposed to operate in a Rankine cycle with pressures
between 10Kpa and 2Mpa and a maximum temperature of 400 ˚ C . What is
the maximum efficiency possible from the power cycle? Ans. 32.32%.
22. Refrigeration Engineering
• is a diverse field and covers a large number of processes ranging from cooling to air conditioning and from food
processes to human comfort by applying refrigeration
Refrigeration
• The science of moving heat from low temperature to high temperature
- Food Storage or
preservation
- Food Production
- Drying
- Air Conditioning
Sample Application: Ice Making
- Brine Circuit
- Refrigeration Circuit
- Cooling Water Circuit
Application:
23. a. QR = Heat Rejected in Condenser
=
b. QA = Refrigerating Effect
=
c. W = Net Work
=
d. COP =Coefficient of Performance
=
e. TR = Tons of Refrigeration:
T2(S1 - S4)
T1(S1 - S4)
QR - QA = (T2 - T1)(S1 - S4)
=
𝑻𝟏
𝑻𝟐 − 𝑻𝟏
=
𝑸𝑨
𝟑. 𝟓𝟏𝟔
𝑸𝑨
𝑾𝑪 𝑺𝟏 − 𝑺𝟒
Where: QA- Heat Added or Refrigerating Effect in KW
Reversed Carnot Refrigeration cycle:
Process 1-2 – Isentropic Compression, s1 = s2
Process 2-3 – Isothermal Heat Rejection, T2=T3
Process 3-4 – Isentropic Expansion, s3 = s4
Process 4-1 – Isothermal Heat absorption, T4=T1
Reversed Carnot cycle as a Heat pump:
=
𝑻𝟐
𝑻𝟐 − 𝑻𝟏
𝑸𝑹
𝑾𝑪
a. COP=
24. Sample Problem
1. A refrigeration system operates on the reversed Carnot cycle. The minimum and
maximum temperatures are -25 0C and 720C, respectively. The heat rejected to the
condenser is 6,000 kJ/min. Draw the T-S diagram, find power input required, and
Tons of Refrigeration developed. 28.11KW, 20.44TR
2. A refrigerating system operates on the reversed Carnot cycle. The highest
temperature of the refrigerant in the system is 120 0F and the lower temperature is
100F. The capacity is to be 20 tons. Determine the heat rejected from the system in
Btu/min, Net Work in Btu/min and Net work in HP. 4936.17Btu/min, 936.17 Btu/min,
22.07 Hp
3. The power requirement of a carnot refrigerator in maintaining a low temperature
region at 238.9K is 1.1kW per ton.
Find a. COP (3.19)
b. T2 (586.64)
c. heat rejected (4.609)
25.
26. Basic Components
Compressor
1. It circulates the refrigerant within the system.
2. It compresses the low pressure gas to high pressure
gas
Expansion Valve
1. Expands the high pressure liquid to a
mixture of low pressure liquid gas particles.
2. Controls the amount of refrigerant in the
evaporator.
Evaporator
1. Acts as heat exchanger between the product and the
refrigerant.
2. Completely vaporize the refrigerant
Condenser
1.Convert the refrigerant from vapor(gas) state to liquid
state.
2.Removes the heat of compression
27. Schematic Diagram
P-h Diagram
Processes:
1 to 2 – Is isentropic compression process(s1=s2)
2 to 3 – Is constant pressure process (P2=P3)
3 to 4 – Is throttling process (H3 = H4)
4 to 1 – Is constant Pressure process (P4 = P1)
28. Components Performance and Formulas
wc = h2 - h1 , kJ/kg
Wc = m(h2 - h1), kW
For cooling water:
qR = h2 - h3 , kJ/kg
QR = m(h2 - h3), kW
where: m = mass of refrigerant circulated
The Vapor Compression Cycle
1. Compressor Power (Wc) - is the power needed to
compress the refrigerant.
2. Heat Rejected (QR) - is the amount of heat
rejected to the cooling medium.
3. Expansion Valve Process (h3 = h4)
h3 = h4 = hf4 + xhfg4
𝒙 =
𝒉𝟒 − 𝒉𝒇𝟒
𝒉𝒈𝟒 − 𝒉𝒇𝟒
hfg4 = hg4 - hf4
where:
X= Quality after expansion
4. Refrigerating Effect (RE) - is the amount of heat gained
from the load.
RE = mw cP (t1 – t2), kW
RE = m(h1 - h4), kW
For chilling water:
QR = mw cP (t2 – t1), kW
RE = h1 - h4, kJ/kg
29. TR =
𝒎(𝒉𝟏 − 𝒉𝟒)
𝟑. 𝟓𝟏𝟔
COP =
𝒉𝟏 − 𝒉𝟒
𝒉𝟐 −𝒉𝟏
COP =
𝑹𝒆𝒇𝒓𝒊𝒈𝒆𝒓𝒂𝒕𝒊𝒏𝒈 𝑬𝒇𝒇𝒆𝒄𝒕
𝑪𝒐𝒎𝒑𝒓𝒆𝒔𝒔𝒐𝒓 𝑷𝒐𝒘𝒆𝒓
5. Tons of refrigeration (TR)
TR =
𝑹𝒆𝒇𝒓𝒊𝒈𝒆𝒓𝒂𝒕𝒊𝒏𝒈 𝑬𝒇𝒇𝒆𝒄𝒕
𝟑.𝟓𝟏𝟔
where:
1 ton of refrigeration
Performance of Refrigeration System
1. Coefficient of Performance (COP) - is
the ratio of refrigerating effect and
compression work
= 3.516 kW
= 200 Btu/min
= 12,000 Btu/hr
𝑾𝒄
𝑻𝑹
=
𝑪𝒐𝒎𝒑𝒓𝒆𝒔𝒔𝒐𝒓 𝑷𝒐𝒘𝒆𝒓
𝑻𝒐𝒏 𝒐𝒇 𝒓𝒆𝒇𝒓𝒊𝒈𝒆𝒓𝒂𝒏𝒕
, 𝑲𝑾/𝑻𝒐𝒏
𝑯𝑷
𝑻𝒐𝒏
=
𝟒. 𝟕𝟏
𝑪𝑶𝑷
𝑲𝑾
𝑻𝒐𝒏
=
𝟑. 𝟓𝟏𝟔
𝑪𝑶𝑷
2. Power Per Ton :
EER =
𝑹𝒆𝒇𝒓𝒊𝒈𝒆𝒓𝒂𝒕𝒊𝒏𝒈 (𝑲𝑾)
𝑬𝒍𝒆𝒄𝒕𝒓𝒊𝒄𝒊𝒕𝒚 𝑪𝒐𝒏𝒔𝒖𝒎𝒑𝒕𝒊𝒐𝒏 𝑲𝑾
= 𝟑. 𝟒𝟏𝟐 𝒙 𝑪𝑶𝑷
3. Energy Efficiency Ratio (EER) – the ratio of energy
removed at the evaporator (refrigerating effects) to the
electrical energy consumed. This shall conform with the
standards set by the Department of energy
4. Volume Flow at Suction (V1)
V1 = mv1 , m3/sec
𝑽𝑷𝑻 =
𝑽𝟏
𝑻𝒐𝒏𝒔 𝒐𝒇 𝑹𝒆𝒇𝒓𝒊𝒈𝒆𝒓𝒂𝒏𝒕
5. Volume Flow Per Ton :
30. A. Chilling and Cooling Load
1. Refrigerating effect = m(h1 - h4)
2. Heat loss from water =mL cp (t1 – t2)
Note: Refrigerating Effect = Product Load
Product load = Heat to be removed from a product
=Sensible load + Latent load
Chilled liquid in the evaporator:
3. Mass of liquid circulated (mL ):
mL =
𝒎(𝒉𝟏−𝒉𝟒)
𝑪𝒑(𝒕𝟏−𝒕𝟐)
where:
m = mass flow of refrigerant
mL = mass of liquid circulated
CP = specific heat of liquid= 4.187 kJ/kg-K for water
t1 = initial temperature of liquid
t2 = final temperature of liquid
Evaporator
mw =
𝒎(𝒉𝟐−𝒉𝟑)
𝑪𝒑(𝒕𝟐−𝒕𝟏)
VW =
𝒎𝑾
𝝆𝑯𝟐𝟎
B. Cooling water in the condenser:
1. Heat Rejected in the condenser (QR)
QR = m(h2 - h3)
QR = mw cP (t2 - t1)
2. Mass of cooling water required (mw):
3. Volume flow of cooling water required, Q:
Condenser
where:
m = mass flow of refrigerant
mW = mass of water circulated
CP = specific heat of water
= 4.187 kJ/kg-K for water
t1 = initial temperature of water
t2 = final temperature of water
𝝆 H20 = density of water
31. d. Over−all efficiency =
𝑷𝒐𝒄
𝑷𝒊𝒎
c. Efficiency of compressor =
𝑷𝒐𝒄
𝑷𝒊𝒄
b. Efficiency of coupling =
𝑷𝒊𝒄
𝑷𝒐𝒎
a. Efficiency of motor =
𝑷𝒐𝒎
𝑷𝒊𝒎
C. Motor and Compressor Performance
where: Pim = power input of motor
Pom = power output of motor
Pic = power input of compressor
Poc = power output of compressor
32. Sample problem.
1. A refrigeration system using refrigerant 22 has the evaporator entrance h = 252.4 KJ/kg exit h = 401.6
KJ/kg. If mass flow of refrigerant is 1.2 kg/s and a coefficient of performance of 2.98, find the compressor
power and heat rejected from the condenser.
2. The heat required to remove from beef 110kg is 36437 KJ which will be cooled from 20 ˚C to -18 ˚C. The
specific heat above freezing is 3.23 KJ/kg-˚K and latent heat of fusion is 233 KJ/kg. If specific heat below
freezing is 1.68 KJ/kg-˚K, find the freezing temperature.
3. A belt driven compressor is used in a refrigeration system that will cool 10 li/sec of water from 130C to
10C. The belt efficiency is 98%, motor efficiency is 85%, and the input of the compressor is 0.7 kW/ton of
refrigeration. Find the mass flow rate of condenser cooling water warmed from 210C to 320C if overall
efficiency is 65%.
4. A standard vapor compression cycle developing 50 kW of refrigeration using refrigerant 22 operates with
a condensing temperature of 350C and an evaporating temperature of -100C. Calculate:
• The refrigerating effect in kJ/kg
• The circulation rate of refrigerant in kg/s
• The power required by the compressor in kW
• Coefficient of performance
• The volume flow rate measure at the compressor suction
• The power per kW of refrigeration
• The compressor discharge temperature4
33. 1. An air conditioning system of a high rise building has a capacity of 350KW of refrigeration using R-22. The
evaporator and condenser temperature are 0˚C and 35 ˚C, respectively. Determine work of compression in KW.
2. The change of enthalpy between the inlet and outlet of evaporator is 1000KJ/Kg and mass flow of refrigerant is
12Kg/min. What is the capacity of plant in Tons of refrigeration.
3. An industrial plant requires to cool 120 gal/min of water from 20 ˚C to 5 ˚C. Determine the Tons of refrigeration
required.
4. A refrigeration system using Freon 12 has a capacity of 320 kw of refrigeration. The evaporating
temperature is -10 degrees C and the condensing temperature is 40C. Calculate the fraction of vapor in
the mixture before the evaporator.
5. Milk must be received and cooled from 80 ˚F to 38 ˚F in 5 hrs. If 4000 gallons of fresh milk received having SG of
1.03 and 𝐶𝑝 = 0.935 Btu per lb- ˚F, find the refrigeration capacity.
Exercises