Chapter 18 Vocabulary Flashcards
1
Q
energy efficiency
A
percentage of the total energy input that does useful work and is not converted into low-quality, usually useless heat in an energy conversion system or process
2
Q
Life cycle cost
A
Initial cost plus lifetime operating costs of an economic good
3
Q
fuel cell
A
- DEVICE THAT COMBINES HYDROGEN AND OXYGEN FUEL TO PRODUCE ELECTRCITY AND WATER VAPOR
- TWICE AS EFFICIENT AS AN INTERNAL COMBUSTION ENGINE
- LESS MACITENCE, LITTLE TO NO POLLUTION,AND HAVE NO MOVING PARTS
4
Q
superinsulated house
A
- Cost 5% more to build (more expensive), however it can save up to $100,000 over a 40yr period
- heavily insulated and airtight
- no need for a back up heating system
- air to air heat exchange
5
Q
ecoroofs (green roofs)
A
they are covered in plants
- good insulation
- absorbs storm water and release it slowly
- outlast conventional rooftops
6
Q
passive solar heating system
A
- absorbs and stores heat from the sun directly within a structure (windows, insulation)
- can lower your electric bill without the need of a system with pumps or mechanical devices
7
Q
active solar heating system
A
- asborbs energy from the sun by pumping a heat-absorbing fluid through special collectors usually on the roof (active solar collectors)
- photovoltaic cells
8
Q
photovoltaic (PV) cells (solar cells)
A
- converts solar energy directly into electrical energy
- semiconducting material that hold electrons that flow causing an electrical current
9
Q
biofuels
A
-substitutions for gas and diesel made from plant materials
Ex) Ethanol and biodiesel
10
Q
geothermal energy
A
heat transferred from the Earth’s underground concentrations of dry steam (steam with no water droplets),, wet steam (a mix of steam and water droplets), or hot water trapped in fractured or porous rock
11
Q
micropower systems
A
Systems of small scale decentralized unites that generate 1-10,000 kilowatts of electricity.
Ex.) microturbines, fuel cells, household solar panels, and solar roofs
12
Q
hybrid electric internal combustion engine
A
-Runs on gasoline, diesel fuel or natural gas, and a small rechargeable battery
13
Q
cogeneration
A
- COMBINED HEAT AND POWER*
- WHEN TWO USEFUL FORMS OF ENERGY ARE PRODUCED BY THE SAME FUEL SOURCE (VERY EFFICIENT)
- USED BY INDUSTRIES TO SAVE MONEY
- GREAT WAY TO IMPROVE ENERGY EFFICIENCY
14
Q
Geoexchange
A
-BURIED PIPES MOVE HEAT IN OR OUT OF THE GROUND DEPENDING ON THE SEASON AND/OR THE HEATING AND COOLING REQUIREMENTS
15
Q
- What is energy efficiency and how much do we waste?
A
84%
16
Q
- How can we save energy?
A
buying more energy-efficient cars, lighting, heating systems, water heaters, air conditioners, and appliances.
17
Q
- Which four widely used devices waste alot of energy? Explain how they waste energy and what percentage of energy is wasted.
A
- incandescent light bulb, nuclear power plant, internal combustion engine, and coal-burning power plant
- the light bulb wastes the most energy. It wastes 95% of its energy input of electricity because it is a heat bulb.
18
Q
- What are two principles for saving energy?
A
- to keep the number of steps in an energy conversion process as low as possible
- to strive to have the highest possible energy efficiency for each step in an energy conversion process
19
Q
- Explain the three ways of saving energy in industry.
A
- cogeneration
- replace energy-wasting electric motors
- switch from low-efficiency incandescent lighting to higher-efficient fluorescent lighting
20
Q
- Explain why average fuel efficiency for new cars rose sharply in the U.S. between 1973 and 1985.
A
government-mandated Corporate Average Fuel Economy standards.
21
Q
- Explain the energy used in a hybrid-electric internal combustion engine car.
A
asoline, diesel fuel, or natural gas and uses a small battery to provide the energy needed for acceleration and hill climbing
22
Q
- What are the positives of fuel cell run cars?
A
- can be run by renewable resources
- twice as efficient as internal combustion engines
- have no moving parts
- require little maintenance
- produce little or no pollution depending on how their hydrogen fuel is produced
23
Q
- See Figure 18-12. What features in a superinsulated house to make it nearly airtight?
A
- r-60 or higher insulation
- small or no north-facing windows or super windows
- r-30 to r-43 insulation
- air-to-air heat exchanger
- insulated glass, triple-panned or super windows
24
Q
- List the ways we can save energy in existing buildings.
A
- insulating and plugging leaks
- using energy-efficient windows
- stopping the heating and cooling losses
- heating houses more efficiently
- heating water more efficiently
- using energy-efficient appliances
- using energy-efficient lighting
- cutting off electrical devices when not using them
- setting strict energy-efficiency standards for new buildings.
25
11. Explain the difference between passive and active solar heating.
A passive solar heating system absorbs and stores heat from the sun directly within a structure using stone, walls, and greenhouses. While, an active solar heating system absorbs energy from the sun by pumping a heat-absorbing fluid though special collectors usually mounted on a roof or on special racks to face the sun.
26
12. See Figure 18-18. List the advantages and disadvantages of passive or active solar heating.
```
Advantages :
-energy is free
-net energy is moderate (active) to high (passive)
-quick installation
-no CO2 emissions
-very low or and water pollution
-very low land disturbance
-moderate cost (passive)
Disadvantages:
-need of access to sun 60% of the time
-blockage of sun access by other structures
-the need for heat storage systems
-a high cost (active)
-active systems need maintenance and repair
-active collectors are unattractive.
```
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13. See Figure 18-19. List the advantages and disadvantages of solar energy for high-temperature heat and electricity.
advantages:
- moderate net energy
- moderate environmental impact
- no CO2 emissions
- fast construction (1-2 years)
- costs are reduced with natural gas turbine backup disadvantages
- low efficiency
- high costs
- a need for backup storage systems
- a need to access to sun most of the time
- high land use
- it may disturb desert areas.
28
14. Explain how we produce electricity with photovoltaic (PV) cells (solar cells).
using new solar-cell room shingles or PV panel roof systems that look like a blue metal roof
29
15. See Figure 18-21. List advantages and disadvantages of solar cells.
advantages:
- fairly high net energy
-it works on cloudy days
-it has quick installation
-it is easily expanded or moved
-there’s no CO2 emissions
-it has low environment impact
-it lasts for 2–40 years
-it has low land use,
- it reduces dependence on fossil fuels
disadvantages:
-it needs access to sun
-it has low efficiency
-it needs electricity storage system or backub
- it has a high-land use that could disrupt desert areas
- it has high costs
-the DC current must be converted to AC.
30
16. Explain the three methods of producing electricity from flowing water.
- large scale hydropower
- small scale hydropower
- pumped storage hydropower
31
17. List advantages and disadvantages of wind power.
```
Advantages:
- it has moderate to high net energy
-high efficiency
-moderate capital cost
-low electricity cost
-very low environmental impact
-no CO2 emission
-quick construction
-its easily expanded
-it can be located at sea
-and the land below turbines can be used to grow crops or graze livestock
disadvantages:
- it needs steady winds
-it needs backup systems when winds are low
-it has a high land use
-it has visual pollution
-the noise can be heard in populated areas
-and it may interfere in fights of migratory birds and kill birds of prey.
```
32
18. How is biomass used to provide energy?
by burning plant materials and animal wastes to provide hear or electricity or converted into gaseous or liquid biofuels
33
19. How are ethanol and methanol processed from biomass as a fuel?
by the conversion of solid biomass fuels to gaseous and liquid biofuels. This causes and produced ethanol and methanol. Methanol is produced from animals and ethanol is produced from plants.
34
20. List advantages and disadvantages of ethanol fuel.
advantages:
- it has high octane
- some reduction in CO2 emissions
- reduced CO emissions
- it can be sold as gasohol
- and its potentially renewable. disadvantages:
- it needs large fuel tanks
- it lowers driving range
- theres a net energy loss
- there is a much higher cost
- corn supplies are limited
- it may compete with growing food on cropland
- it has higher NO emissions
- its corrosive
- its hard to start in cold weather.
35
21. List advantages and disadvantages of methanol fuel.
advantages:
- it has high octane
- some reduction on CO2 emissions
- it lowers total air pollution
- it can be made from natural gasagricultural wastes, sewage sludge, and garbage
- it can be used to produce H2 for fuel cells
disadvantages:
- it needs large fuel tanks
- half the driving range
- it corrodes metal, rubber, and plastic
- it has high CO2 emissions if made from coal
- its expansive to produce
- and its hard to start in cold weather.
36
22. What is geothermal energy and how is it used to warm structures?
by using the heat stored in the earth’s mantle to cool buildings to produce electricity, which cause heat to turn on. It is also used by geothermal heat pumps, geoexchange, and geothermal exchange
37
23. List advantages and disadvantages of geothermal energy
advantages:
- it has very high efficiency,
- moderate net energy at accessible sites
- it lowers CO2 emissions than fossil fuels
- lowers costs at favorable sites
- it has low land use
- and it has moderate environmental impact
disadvantages:
- it has a scarcity of suitable sites
- its depleted if used too rapidly,
- it has CO2 emissions
- it has moderate to high local air pollution
- it has noise and odor
- and it costs too high except at the most concentrated and assessable areas
38
24. List advantages and disadvantages of hydrogen fuel.
advantages:
- it can be produced from plentiful water
- it has low environmental impact
- its renewable if produced from renewable resources
- it has no CO2 emissions if produced from water
- its a good substitute for oil
- it has a competitive price if environmental and social costs are included in the cost comparisons
- its safer than gasoline and natural gas
- it’s nontoxic
- and high efficiency in full cells. disadvantages:
- it is not found in nature
- energy is needed to produce fuel
- it has a negative net energy
- CO2 emissions are produced from carbon-containing compounds
- it’s nonrenewable if generated by fossil fuels or nuclear power,
- it has high costs
- it has a short driving range for current fuel cell cars
- there is no fuel distribution system in place
- and excessive H2 leaks may deplete ozone.
