HEAT ENGINES AND REFRIGERATION
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Transcript of HEAT ENGINES AND REFRIGERATION
HEAT ENGINES AND REFRIGERATION
PRESENTATION BY GROUP 1 CLASS D
IDEHEN OSAHON MOSES 20559AYOKUNLE OLUWOLE DAVID 20530AHMAD ABUBAKAR SHEHU 20464NWABUEZE GIFT CHIMUANYA 20614AKHIGBE PETER OSEREME 20507MBEE OLEMAKPADU NELSON 20821
ANYANWU OBINNA THOMPSON 20825
OUTLINEINTRODUCTIONTHEORETICAL ANALYSES OF CYCLESPRACTICAL APPLICATIONSFURTHER RESEARCHCONCLUSION
INTRODUCTION
•Any device that transforms heat partly into work
•The working substance could beAir and fuel mixture in ICE
Steam in Steam Engines
What is a Heat Engine?
First Law of Thermodynamics
-a principle of conservation of energy
INTRODUCTION
HEAT Q
W
Heat Applied
Work Done
• It is impossible to transform all of the heat energy transferred to a system into useful work.
INTRODUCTIONSecond Law of Thermodynamics
Forward and Reverse enginesForward Engines Reverse EnginesHeat moves from hot
source to cold sinkWork is done by the
systemExamples are ICE,SE
Heat moves from cold source to a hot sink
Work is done on the system
Examples are Refrigerators and A/C
INTRODUCTION
1 to 2 Isothermal heat Supply3 to 4 Isothermal heat rejection2 to 3 Adiabatic Expansions (Isentropic)4 to 1 Adiabatic Compressions (Isentropic)
The Carnot Efficiency (1)
THEORETICAL ANALYSIS
Carnot Cycle
Best EfficientHeat supplied at upper fixed temperatureRejected at lower fixed temperature
Otto Cycle (Ideal Air Standard Cycle - Petrol Engine)1 to 2 Isentropic Compressions2 to 3 Reversible constant Volume heating3 to 4 Isentropic Expansions4 to 1 Constant Volume HeatingCompression ratio (2)
Efficiency , (3)
(4) (5)Otto Cycle efficiency is a function of compression ratio.
THEORETICAL ANALYSIS
Diesel Cycle Develop by Diesel in 1892 Compression Ignition 1 to 2 Isentropic Compressions2 to 3 Reversible Constant Pressure heating3 to 4 Isentropic Expansion4 t0 1 Constant Volume cooling. Making similar computations (6)
(7)
The efficiency depends on the compression and cut off ratios.
THEORETICAL ANALYSIS
𝛽=𝑣3𝑣2
Refrigeration Cycle
W
Q2
Q 1
(7)
(8)
1
23
4
THEORETICAL ANALYSIS
PRACTICAL APPLICATIONS1. Internal Combustion Engine (in cars and
airplanes)
2. Gas Turbine Engine
Gas turbines are similar to piston engines except that the four steps occur at different places. The four sections include:1. The inlet section2. The compressor section3. The combustion section (the combustor)4. The turbine (and exhaust) section.Applicable in airplanes and gas power plants
3. Refrigerator and Air conditioner
The major parts of the AC/refrigerator are:Evaporator - Receives the liquid refrigerant. Converts liquid to gasCompressor - A pump that pressurizes gaseous refrigerant Condenser - Facilitates heat transfer to the surrounding. Gas is condensed to cool liquidExpansion valve - regulates refrigerant flow into the evaporatorMajor differences are : supply of gases, circulation system and type of vaporization
FURTHER RESEARCHEfficiency of heat EnginesPollutionMagnetic heat EnginesElectric Cars
CONCLUSIONHeat Engines and Refrigeration play
important roles in our lives.
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