Energimaskiner Workshop efterr 2010 1 Program 08:15-09:30 - - PowerPoint PPT Presentation

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Energimaskiner Workshop efterr 2010 1 Program 08:15-09:30 - - PowerPoint PPT Presentation

Jun 12, 2023 250 likes •697 views

Energimaskiner Workshop efterr 2010 1 Program 08:15-09:30 Forelsning 09:30-14:00 Miniprojekt i grupper 14:00-15:00 Fremlggelse i plenum 2 Forlsning Carnot Sterling (m. demo) Miniprojekter Varmepumpe Benzin motor

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SLIDE 1

Energimaskiner

Workshop efterår 2010

1

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SLIDE 2

Program

  • 08:15-09:30 Forelæsning
  • 09:30-14:00 Miniprojekt i grupper
  • 14:00-15:00 Fremlæggelse i plenum

2

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SLIDE 3

Forlæsning

  • Carnot
  • Sterling (m. demo)
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SLIDE 4

Miniprojekter

Varmepumpe Benzin motor Diesel motor Kraftværk Refrigerator, heat pump Otto cycle Diesel cycle Rankine cycle

  • Mindre emner: Pumpe, turbine, kompresser, drøvle ventil (throttling valve),

Intercooler, regenerator, varmeveksler

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SLIDE 5

Præsentation

  • 10-30 min, 1-2 personer

1. Beskrivelse af systemet væsentlige komponenter 2. Beskriv systemet i PV-diagram 3. Angiv typiske effektivitet 4. Andet…Fordele og ulemper…

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SLIDE 6
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SLIDE 7

First little history

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SLIDE 8

External combustion engine

  • Papins “pressure cooker”

– Steam can move a piston – valves

  • Savery (1698) firsts steam engine

– Horsepower – Draining mines – http://library.thinkquest.org/C006011/english/jsit es/steam_thomas_savery.php3?f=2&b=50&j=1&fl =1&v=2

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SLIDE 9

External combustion engine

  • Newcomens steam engine

– 1712

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SLIDE 10

External combustion engine

  • Watts 2nd steam engine

– Double piston stoke – 1775

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SLIDE 11

Steam locomotives

  • From 1804
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SLIDE 12

Steam turbines

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SLIDE 13

Sterling engines

  • Sterling (1820)
  • http://library.thinkquest.org/C006011/english

/sites/stirling.php3?f=2&b=50&j=1&fl=1&v=2

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SLIDE 14

Internal combustion engine

  • Two stroke engine
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SLIDE 15

Internal combustion engine

  • 1862 Otto - two stroke
  • 1879 Benz - first car
  • 1892 Diesel – compression ignition

and many more people should be mentioned…

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SLIDE 16

End of history lesson

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SLIDE 17

Sterling engine

Step 0. Thermal properties of air

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

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SLIDE 18

Sterling engine

Step 1. Add a work piston…

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

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SLIDE 19

Sterling engine

Step 2. Add a displacement “piston”…

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

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SLIDE 20

Sterling engine

  • Displacement Piston

– Sufficient gab to allow air movement – Should be as light as possible – “piston” needs a transfer of work to move – Creates two temperature zones in the cylinder

Cold zone Cooling ribs Hot zone Heat source

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SLIDE 21

Sterling engine

Step 3. Add Crankshaft to working piston

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

up and down movement  rotating motion

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SLIDE 22

Sterling engine

Step 4. Couple the two pistons

Use some of the work from the working piston to move the displacement piston

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

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SLIDE 23

Sterling engine

Step 5. Add a flywheel

A flywheel stores energy

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

The sterling engine uses energy in half its cycle The more heavy the flywheel is, the more continuous motion β-type sterling engine

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SLIDE 24

Sterling engine

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

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SLIDE 25

Sterling engine

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

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SLIDE 26

Sterling engine

  • Other configurations: α-type

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

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SLIDE 27

Sterling engine

  • Other configurations: γ-type

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

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SLIDE 28

Sterling engine

  • Ideal (non-physical) Sterling engine

Piston moves up, work is done on the piston Piston moves down, this requires work Displacer moves down, displacement volume connected to cold zone Displacer moves up, displacement volume connected to hot zone

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SLIDE 29

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Stempelarbejde

  • Det udførte arbejde afhænger af procesvejen
  • For en kredsproces, der løber fra tilstand 1 til tilstand 2 via procesvej B, og retur

via procesvej A, er arbejdet positivt

  • For den modsatte proces er arbejdet negativt

V p 1 2 1 2

Areal under procesvej A = arbejde udført ved denne proces Areal under procesvej B = arbejde udført ved denne proces

V p 1 p

+ =

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SLIDE 30

Sterling engine

Iso-term (or iso-thermal) Iso-chor Iso-term Iso-chor

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SLIDE 31

Sterling engine

  • If we consider the work transferred to the ‘working’ fluid

3 2 3 2 2 2 3

ln per unit mass of gas Heat transferred from hot zone W pdv p RT p

−

= = −   =    

∫

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SLIDE 32

Sterling engine

  • Cycle efficiency

– Total work done – Ideal efficiency

2 1 3 1 2 3 2 1 2 4

ln 1 1 ln p RT p T Q Q T p RT p η

−

      = = − = −      

∑

2 1 2 1 3 4

ln ln p p W Q RT RT p p     = = −        

∑ ∑

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SLIDE 33

Sterling engine

  • What reduces the efficiency for a real engine?
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SLIDE 34

Sterling engine

  • More realistic sterling cycle

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN

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Carnot cycle

  • What is the maximum possible efficiency of

any engine/cycle?

  • Answer: The Carnot efficiency, the efficiency
  • f the Carnot cycle
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SLIDE 36

The Carnot cycle

  • Cycle efficiency can be optimized using

processes that uses the least amount of work and delivers the most.

  • Carnot (1820) created this theoretical engine
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SLIDE 37

The Carnot cycle

  • Overview

iso-thermal compression Abiabatic compression Iso-termal expansion Abiabatic expansion

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SLIDE 38

The Carnot cycle

  • Proces 1-2: Isothermal expansion

– Cylinder connected to hot zone – Work is done on piston (piston moves) – As P drops so tends T – But, we assume that heat is transferred infinitely fast! – Thus, it is an irreversible isothermal process

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SLIDE 39

The Carnot cycle

  • Proces 2-3: adiabatic expansion

– The hot zone is replaced by perfect insulation – Volume continue to expand, doing work on the piston – Temperature drops due to the ideal gas law – Piston moves fictionless

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SLIDE 40

The Carnot cycle

  • Proces 3-4: Isothermal compression

– Insulation is replaced by cold zone – piston is doing work on the fluid as the piston moves – As the gas is compressed the temperature tends to increase – again, we assume that heat is transferred infinitely fast! – it is an irreversible isothermal process

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SLIDE 41

The Carnot cycle

  • Proces 4-1: adiabatic compression

– The cold zone is replaced by perfect insulation – Piston continue to compress the fluid volume – Temperature increases due to the ideal gas law – Piston moves fictionless

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SLIDE 42

The Carnot cycle

  • The Carnot efficiency

This applies for all ideal heat engines! The efficiency of a plant/engine

  • perating at different temperatures

should be compared to the Carnot efficiency not 100%

1 2

1 1

L H

Q T Q T η = − = −

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SLIDE 43

The Carnot cycle

Source: Peter Fette, http://www.stirling- fette.de/peter.htm#EN