1 chapter 7 energy conservation lecture #14 hnrt 228 energy and the environment
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Chapter 7Energy Conservation
Lecture #14HNRT 228Energy and the Environment
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iClicker Question
• About what percentage of U.S. electricity is derived from nuclear power?– A 10– B 20– C 30– D 40– E 50
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iClicker Question
• About what percentage of U.S. electricity is derived from nuclear power?– A 10– B 20– C 30– D 40– E 50
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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
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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
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• 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
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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
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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
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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
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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
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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
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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.
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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.
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Overview of Chapter 7
• Energy Conservation– Space Heating– Thermal Insulation– Air Infiltration– Lighting– Appliances– Some considerations of agriculture
and industry
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Adapted from
Home Energy Seminar at Tufts University with Professor Anja
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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
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N.B. Addressing Energy Conservation Issues May
Help Address Other Issues
Energy SecurityNational Security
Job SecurityAir Pollution
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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!
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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.
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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.
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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
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• 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
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• 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
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If every household in the US replaced its fixtures with CFLs
Possible Savings: 800 million
MWh
Compact fluorescent bulbs
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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
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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.
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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.
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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
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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
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BAD: Top-loader GOOD: Front-loader
Washing Machines
40 to 60% less water 30 to 50% less energy 50 to 70% less detergent
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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
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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…
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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.)
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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!
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iClicker Question
• Which type of washing machine conserves the most energy and water?– A Top loader– B Front loader– C There is no difference
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iClicker Question
• Which type of washing machine conserves the most energy and water?– A Top loader– B Front loader– C There is no difference
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Myth
Turning off your computer
will harm it.WRONG!
This used to be true back when computers had green screens and punched cards……
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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.
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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.
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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:
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Will she be warm enough in the winter?Convection:
Air leaks:This is why you wear a wind breaker
over your woolen sweater!
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Blower-Door Test
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Where is the Energy Going?Ceiling
4%
Doors1%Windows
13%
Floor10%
Equip. Efficiency
16%
Infiltration34%
Walls22%
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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
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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.
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Lower Conduction with
Insulation:This is why you wear a
woolen sweater in winter and a cotton sweatshirt in the summer
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Infra-red Photography
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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
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Two components to good weatherization
Minimize air leaks
Optimize insulation
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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
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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
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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
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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
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How Your House Loses Heat
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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!
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Insulation materials
Fiberglass
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Insulation materials
Cellulose
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Fiberglass Vs. Cellulose
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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
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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
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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
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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
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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
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Cellulose Installation
Pay back is 1-5 years Cost: $1000 - $5000
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Insulation MaterialsSpray-foamsIcynene; 2-part polyurethanes;
Soy-based
Rigid foams
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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
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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.
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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
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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.
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Windows:
Invest in good storms, weather stripping, caulk, plastic
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Largest energy expense in the home.
What system? Steam, hot water, forced air?
Gas, oil, electric, wood
Heating Systems
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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!
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Efficiency
Check www.energystar.gov
Go for over 90% efficiency. (Gas boilers can achieve higher efficiencies.)
Check for rebates!
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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
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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
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#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.
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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
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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
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Roof venting: Ice dams
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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)
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