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Fall wk 3 – Mon.11.Oct.04 • Welcome, roll, questions • Thermal physics and Energy Ch.3 • break • continue Calculus Ch.1 • Looking ahead Energy Systems, EJZ
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Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Dec 21, 2015

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Page 1: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Fall wk 3 – Mon.11.Oct.04

• Welcome, roll, questions

• Thermal physics and Energy Ch.3

• break

• continue Calculus Ch.1

• Looking ahead

Energy Systems, EJZ

Page 2: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Discuss Ch.3, Conventional conversion of energy

• Key points?

• Insights from team discussion?

• Questions?

- questions of fact: Can we find answer in the text? What page?

- Outstanding questions of fact

- Outstanding significant questions

Page 3: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Energy conversion - outline

• Scientific principles – App.A

• Review of Thermal Physics

• New: Power and Efficiency

• Steam plant: closed cycle

• Engine cycles: open

Page 4: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Laws of Thermodynamics

0. Thermal equilibrium

1. Energy can be neither created nor destroyed.

Ex: Heat in = Work done + internal energy

2. Entropy increases: useful energy is lost to heat

Page 5: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Heat = energy = workEnergy = force * distance

Joule = Newton * meter

J = kg m2/s2, cal = 4.1868 J = 4 x 10-3 BTU

Horsepower = 1 hp = 550 ft * lb/s = 746 Watt

POWER = rate of doing work = Energy/time

Watts = Joules/sec

Efficiency = Energyin / Energyout = Powerin / Powerout

Q: What is a kilowatt-hour? A measure of:

A. Energy B. Power C. Efficiency

Page 6: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Thermal energy heat engine

Steam power plant

• closed cycle, external combustion

• burn fossil fuel heat water steam move turbines electricity

Gas and diesel engines

• open cycle, internal combustion

• compress heat ignite expand motion

Page 7: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Steam plantburn fuel heat water steam move turbines electricity

Increase efficiency by

decreasing losses

Page 8: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Generator: motion electricity

Electric Power = Voltage * Current: P = VI

Ohm’s law: Voltage = Current * Resistance: V = IR

Higher voltage transmission: lower ohmic losses

Page 9: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Engine cyclescompress heat ignite expand motion

Gas engines are usually less efficient than diesel engines

Page 10: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Work done by a gas (CT 3, 64, green)

Work done = pressure * volume = area under curve (clockwise)

Heat added = work done + change in internal energy of gas

Page 11: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

How to improve engine performance?

• thermal efficiency is limited, since waste heat is exhausted

• compression ratio – diminishing returns, and higher temps preignition

• * lower weight better performance: a = F/m

• aerodynamics – small effect

• power train designs – gradual improvements

• * driving habits, mass transit

Page 12: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Calculus - outline

• Modified Calc HW• Practice with logarithmic functions

(Pre)Calculus question for seminar:If global energy use increases by 2.5% per year, how long will it take for global demand to double?

a. First, guess.b. What is the percent increase if it doubles?

c. Hint: D = D0 at

Page 13: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Calc 1 HW 2

Homework due this Thus: Calc 1 HW 2 without Ch.1.5

1.4 # 1, 2, 9, 11, 14, 18, 26, 35

1.6 # 2, 4, 14, 28

Next Thus: Calc 1 HW 3

1.5 # 1, 10, 14, 16, 20, 29, 31, 34, 36

1.6 # 8, 18, 23

Page 14: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Phys 18 HW 1

Thermal (and basic) physics problems due this Thus:

Ch.1 #5, 7, 16, 18, 24, 26, 29

Ch.18 #4, 5, (24), 26, 28, 35, (73, 85)

Problems in (parentheses) are not available on eGrade.

Hand them in separately?

I will post solutions after class Thus.

Phys 18 HW 2 due next Thus:

Ch.18 # (27), 29, 32, 33, (94)

Page 15: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Looking ahead

• Seminar in Sem II C2109 tonight

• Please put your team’s best Q on the board

before 5:00 so we can start on time

• Tomorrow:– Debate: Coal vs Fission– visitors will discuss sustainability and solar

panels on Tuesday and Wednesday

• Later:- TA available here Wed 1-3, QRC Fri 10-12

- Next Mon. CE Fair – we’ll set up telescope

Page 16: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Heat of transformation ConcepTests

80

Page 17: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Work done by gas ConcepTests

Page 18: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Steam plant cycle

Page 19: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Diesel engine cycle

Page 20: Fall wk 3 – Mon.11.Oct.04 Welcome, roll, questions Thermal physics and Energy Ch.3 break continue Calculus Ch.1 Looking ahead Energy Systems, EJZ.

Hydroplant