1

Chapter 7Energy Conservation

Lecture #14HNRS 228Energy and the Environment

2

iClicker Question

• About what percentage of U.S. electricity is derived from nuclear power?– A 10– B 20– C 30– D 40– E 50

3

iClicker Question

• About what percentage of U.S. electricity is derived from nuclear power?– A 10– B 20– C 30– D 40– E 50

4

iClicker Question

• Which of the following countries has the highest percentage of electricity generated by nuclear power?– A United States– B United Kingdom (Great Britain)– C Japan– D France– E Russia

5

iClicker Question

• Which of the following countries has the highest percentage of electricity generated by nuclear power?– A United States– B United Kingdom (Great Britain)– C Japan– D France– E Russia

6

• Which of the following describes the Roentgen?– A the unit of absorbed dose equivalent.– B the unit of absorbed dose.– C the unit of exposure to ionizing radiation– D all of the above– E none of the above

iClicker Question

7

iClicker Question• Which of the following describes the

Roentgen?– A the unit of absorbed dose equivalent.– B the unit of absorbed dose.– C the unit of exposure to ionizing radiation– D all of the above– E none of the above

8

iClicker Question

• Which of the following describes the RAD?– A the unit of absorbed dose equivalent.– B the unit of absorbed dose.– C the unit of exposure to ionizing radiation– D all of the above– E none of the above

9

iClicker Question

• Which of the following describes the RAD?– A the unit of absorbed dose equivalent.– B the unit of absorbed dose.– C the unit of exposure to ionizing radiation– D all of the above– E none of the above

10

iClicker Question

• Which of the following describes the REM?– A the unit of absorbed dose equivalent.– B the unit of absorbed dose.– C the unit of exposure to ionizing radiation– D all of the above– E none of the above

11

iClicker Question

• Which of the following describes the REM?– A the unit of absorbed dose equivalent.– B the unit of absorbed dose.– C the unit of exposure to ionizing radiation– D all of the above– E none of the above

12

iClicker Question

• Which statement is true about fusion?– A Fusion is just another name for nuclear

fission.– B Fusion and fission are variations of the

same nuclear process.– C Fusion is the breakup of heavier chemical

elements into lighter chemical elements.

– D Fusion is the process of producing heavier chemical elements from lighter

chemical elements.– E Fusion is the process of converting energy

into matter.

13

iClicker Question

• Which statement is true about fusion?– A Fusion is just another name for nuclear

fission.– B Fusion and fission are variations of the

same nuclear process.– C Fusion is the breakup of heavier chemical

elements into lighter chemical elements.

– D Fusion is the process of producing heavier chemical elements from lighter

chemical elements.– E Fusion is the process of converting energy

into matter.

14

Overview of Chapter 7

• Energy Conservation– Space Heating– Thermal Insulation– Air Infiltration– Lighting– Appliances– Some considerations of agriculture

and industry

15

Adapted from

Home Energy Seminar at Tufts University with Professor Anja

16

Home Energy Seminar Overview

• Home Energy - Lights

• Home Energy - Appliances

• Fridges,Washing machines,AC

• Home Energy - A little Physics

• Building diagnostics

• Insulation vs. Air-tightness

• Home Energy - Windows

• Home Energy - Heating Systems

17

N.B. Addressing Energy Conservation Issues May

Help Address Other Issues

Energy SecurityNational Security

Job SecurityAir Pollution

18

Efficiency Thoughts

An estimated 94% of materials become waste before a product is even

manufactured.

Only 6 per cent of materials extracted each year are

embodied in durable goods!

19

Home Energy Seminary

Save Money! Protect the Climate!

Americans spend more than $160 billion a year to heat, cool, light and live in our homes.

Homes use about 21% of the energy we use as a nation. Homes contribute about 17% of our national emissions of greenhouse gases.

20

Compact Fluorescent Light bulbs (CFLs)

More expensive upfront ($1-$12) but they can save $30-$50 over lifetime of bulb.

Many different types of CFLs available (including for small fixtures, 3-ways, etc).

Last 10 times longer!

Watch for available rebates.

Some chemical safety issues.

21

Compact fluorescent bulbs• Take 1-2 min to reach fullest brightness

• Are less bright when it is cold• If concerned about brightness, buy higher wattage• Should not flicker after 1-2 seconds

22

• Are not all of equally good quality • Test out a brand before you invest much in them

Compact fluorescent bulbs• Regular CFLs don’t work in dimmable fixtures

• Buy a dimmable CFL

• Check out www.efi.org for other specialty bulbs

23

• Have a small amount of mercury: call your locality about proper disposal.

• But they still use less mercury than would have been produced at the power plant when you use a regular incandescent bulb

Compact fluorescent bulbs

24

If every household in the US replaced its fixtures with CFLs

Possible Savings: 800 million

MWh

Compact fluorescent bulbs

25

Halogen Torchieres Nice light but…Energy Hog!

Uses 300W – 500W….

(a normal bulb uses 60W)

Halogen torchieres are also a fire hazard!

Buy a torchiere which uses a CFL

26

AppliancesEnergy Star: www.energystar.gov

Look for the energy star label! More than 35 product categories are available with the ENERGY STAR label.

Careful! Energy Star appliances are rated by size class.

Look for the smallest appliance that fits your needs.

27

28

RefrigeratorIf your refrigerator is more than 8 years old, it makes sense to replace it. The new one will pay for itself in energy savings in about 3-6 years.

Again! Energy Star appliances are rated by size class.

Look for the smallest refrigerator that fits your needs! Side-by-side are least efficient.

29

iClicker Question

• How many fewer power plants might be needed if every household changed to compact fluorescent lighting?– A About one– B More than one– C More than 100

30

iClicker Question

• How many fewer power plants might be needed if every household changed to compact fluorescent lighting?– A About one– B More than one– C More than 100

31

BAD: Top-loader GOOD: Front-loader

Washing Machines

40 to 60% less water 30 to 50% less energy 50 to 70% less detergent

32

Top-loader: 40 gallons of water per load. Front loader: 20 - 25 gallons. You could save as much as 7,000 gallons of water per year!

Gentler on clothes.Decreases drying time considerably.Do a better job cleaning clothes. Be modern, get a front-loader! Top-loaders are the technology your grandparents usedOnly do full loads. Use cold water as often as possible.

Front –loading Washing Machines

33

Conventional Dryer

• 800-1000 kW/year

•$80-$120/ year

Be old-fashioned - dry your clothes like your grandparents did!

Tip: If you do not have time to hang all your clothes, hang the heavy, and thick items: towels, sheets, socks…

34

Use Fans Instead of AC!

Only 10-15% of the energy an AC uses.

(Shut the fan off when you leave the room, because it does not actually cool the air but just move it. The exception to this is a window fan to get cool night air from the outside into the house.)

35

Be cheap! Turn it off!

Most electricity is used by things that are on a lot and use a lot of power:

Refrigerator (500kWh-1300 kWh per year)

Freezer (500kWh-1300 kWh per year)

Desktop Computer (300-1000 kWh per year)

Lights

Don’t forget to turn your heat or AC off /down!

36

iClicker Question

• Which type of washing machine conserves the most energy and water?– A Top loader– B Front loader– C There is no difference

37

iClicker Question

• Which type of washing machine conserves the most energy and water?– A Top loader– B Front loader– C There is no difference

38

Myth

Turning off your computer

will harm it.WRONG!

This used to be true back when computers had green screens and punched cards……

39

Myth

Leaving your heat on is more efficient than turning it down because you need so much

energy to heat the house back up.

WRONG!

Think about it!

It’s as if you’d claim that putting down your suitcase while waiting for the bus uses more energy

than holding it up the whole time, because you’d have to pick it up again.

40

Get a Home Energy Audit

A professional will be able to analyze your house and give you advise.

You’ll get most out of it, if you are well educated.

Prepare well and ask lot’s of questions.

41

Convection

The flow of hot and cold gases

This is how heat travels through leaks, cracks and gaps in your house.

A Little Physics:

How Heat Travels:

42

Will she be warm enough in the winter?Convection:

Air leaks:This is why you wear a wind breaker

over your woolen sweater!

43

Blower-Door Test

44

Where is the Energy Going?Ceiling

4%

Doors1%Windows

13%

Floor10%

Equip. Efficiency

16%

Infiltration34%

Walls22%

45

What You Can Do:Use weather stripping and caulking.

It is cheap and it works.

Stay warmSave Money

From the simple to the sophisticated, air sealing pays

46

Heat exchange between adjacent molecules

Conduction

This is how heat travels through materials.

Some materials conduct heat better than others.

Insulation slows the movement of heat.

47

Lower Conduction with

Insulation:This is why you wear a

woolen sweater in winter and a cotton sweatshirt in the summer

48

Infra-red Photography

49

Windows are rated by: Conductance: U-value

Low U-value = high insulation properties

You want: Low U- Value

Insulation is rated by:

Resistance: R-ValueHigh R-value = high insulation properties

You want: High R- Value

50

Two components to good weatherization

Minimize air leaks

Optimize insulation

51

iClicker Question

• Which unit is used to measure insulation of walls?– A Q-value– B R-value– C S-value– D T-value– E U-value

52

iClicker Question

• Which unit is used to measure insulation of walls?– A Q-value– B R-value– C S-value– D T-value– E U-value

53

iClicker Question

• Which unit is used to measure insulation of windows?– A Q-value– B R-value– C S-value– D T-value– E U-value

54

iClicker Question

• Which unit is used to measure insulation of windows?– A Q-value– B R-value– C S-value– D T-value– E U-value

55

How Your House Loses Heat

56

Insulation (conduction):

Get your walls and attic insulated!

Insulating your walls and attic, along with addressing leaks around your doors and windows, can save as much as 30% on your heating bill.

Insulate before you replace windows: it will cost you much less and save you more.

Watch out for active knob-and-tube wiring before you insulate!

57

Insulation materials

Fiberglass

58

Insulation materials

Cellulose

59

Fiberglass Vs. Cellulose

60

Fiberglass vs. CelluloseFiberglass: like a woolen sweater+ easy to install+ can be cheaper + moisture tolerant- does not stop air flow- poor fire protection- most of the times poorly installed

Cellulose: like a down jacket+ stops air flow+ better fire protection+ can fill up nooks and crannies.- does not tolerate moisture very well

61

iClicker Question

• Which of the following will conserve more energy.– A A wall with R-value 12– B A wall with R-value 14– C A wall with R-value 16– D A wall with R-value 18– E A wall with R-value 20

62

iClicker Question

• Which of the following will conserve more energy.– A A wall with R-value 12– B A wall with R-value 14– C A wall with R-value 16– D A wall with R-value 18– E A wall with R-value 20

63

iClicker Question

• Which of the following will conserve more energy.– A A window with U-value 0.12– B A window with U-value 0.14– C A window with U-value 0.16– D A window with U-value 0.18– E A window with U-value 0.20

64

iClicker Question

• Which of the following will conserve more energy.– A A window with U-value 0.12– B A window with U-value 0.14– C A window with U-value 0.16– D A window with U-value 0.18– E A window with U-value 0.20

65

66

Cellulose Installation

Pay back is 1-5 years Cost: $1000 - $5000

67

Insulation MaterialsSpray-foamsIcynene; 2-part polyurethanes;

Soy-based

Rigid foams

68

General Insulation Strategies

Use an insulation that air-seals and insulates– Spray foam– Dense-pack (or wet-spray) cellulose

When practical, insulate the outermost plane– Attic roof rather than floor joists– Crawlspace floor and walls rather than

ceiling– Basement walls rather than ceiling

Slide by Paul Eldrenkamp @ Byggmeister

69

RadiationElectro-magnetic waves emitted from hot objects

This is the how the sun heats the surface of the earth. This is why it can get very hot in a car in the summer.

70

Window Replacement

+ New high-quality windows are definitively more energy-efficient and will cut your heating bills.

+ You’ll get rid of lead paint.

+ New windows are easier to operate and clean.

- High-quality windows are expensive ($300-$600 per opening)

- They have a very long pay back (30-50 years)

- Esthetics

71

Window Replacement

The Don’t’s• Don’t get single pane.• Don’t be lured by the cheap price of some windows. You get what you pay for.

The Do’s• Get double or triple pane windows. • Get high quality windows.• Make sure to get an experienced installer who will pay attention to details (and insulate the weight box)• Get Low-e coating with argon fill. • Wood or fiberglass frames are best.

72

Windows:

Invest in good storms, weather stripping, caulk, plastic

73

Largest energy expense in the home.

What system? Steam, hot water, forced air?

Gas, oil, electric, wood

Heating Systems

74

Sizing?

Most systems are oversized

To tell how much, see how long it runs out of each hour during cold weather.

If less than half the time, a smaller system will save energy.

Replacing your system:

Insist on a heat loss analysis

If your plumber sizes the system by the old system,take your business elsewhere!

75

Efficiency

Check www.energystar.gov

Go for over 90% efficiency. (Gas boilers can achieve higher efficiencies.)

Check for rebates!

76

Don’t trust just your plumber!

A little upfront research can make a big difference.

Recommended reading:www.aceee.org/consumerguide/

index.htm

Replacing a Heating System

77

Stay away from electric heat.

It’s very expensive.

No electric water heaterNo electric furnacesNo space heaters

Electric Heat

Exception: If you want to heat only a small space in a large house

78

#2 Heating Oil

1/3 more carbon emissions than natural gas

Natural Gas

More climate friendly

More chimney friendly

Less air pollution

No oil tank

More expensive than oil….

Home Oil or Gas?

… unfortunately, doing the right thing is not always the cheaper thing…

Also:

Efficiency can make up for it.

79

High-cost but low-impact issues

Vapor barriers– Vapor diffusion varies largely

based upon climate– Big difference between a vapor

barrier and an air barrier – Vapor barrier can be painted

80

81

High-cost but low-impact issues

Roof venting– Cold roof vs. hot roof (vented vs.

unvented)– Instead of investing heavily in

venting, invest in better roof insulation

82

Roof venting: Ice dams

83

Summary

• Saving energy in a home does more than just save money.

• Solve the big problems first—health & safety issues

• Control moisture and pollutants at source• Air-seal and insulate (with the same

material if possible)• Perform pre- and post-weatherization

evaluations (blower door, infrared)