Unit D Section 3.4 Flashcards
What do The energy-efficient designed devices do?
uses less electricity to carry out functions. This reduces the energy to carry out functions.
What are the factors that reduce efficiency?
-friction- Moving parts create friction within a system
This friction is one cause of energy loss in these engines.
-hot exhaust and heat transferred to the cooling system.
How can efficiency be increased?
Increasing the efficiency of a device depends on its purpose
- To increase efficiency is to decrease the friction.
- Add more insulation around the oven in a stove reduces in a stove reduces the amount of heat escaping through the walls of the oven. Same can go for a fridge.
fossil fuels
about 65% of all electric power is generated by burning oil, coal, or natural gas.
These fuels are often called fossil fuels because they formed from the decomposition of prehistoric plants and animals.
Where are fossil fuels used in?
Most of the fossil fuel used in power plants is coal.
How do we use coal to turn a generator?
- The coal is powdered, then blown into a combustion chamber and burned to release heat
- The heat boils water and superheats the resulting steam to a high temperature and pressure
3.This high-pressure steam drives a large turbine.
Steam striking the blades turns the turbine.
- The turbine shaft rotates large electromagnetic coils in the generator to produce electricity.
- Oil or natural gas can be burned in the combustion chamber instead of coal.
What is turbine?
The turbine is a long shaft with many fan blades.
What is another way to produce steam in power plants
nuclear reactors
What is nuclear fission?
In a nuclear reactor, atoms of a heavy element, usually uranium, are split in a chain reaction.
This splitting, known as nuclear fission, releases an
enormous amount of energy
What is a natural way of generating electricity?
(GEOTHERMAL ENERGY) Heat from Earth’s core can also be used to generate electricity
The steam is channelled through pipes and
used to drive turbines.
What is geothermal energy?
hot water and steam naturally come to the
surface after having been heated by hot rock within Earth’s crust. This is
called geothermal energy
What is an another source of fuel? other than fossil fuels, geothermal energy, and nuclear fission?
biomass
When biodegradable waste in landfills is decomposed
it produces combustible gases that can be collected and used as fuel for steam-driven generators.
The waste heat from the manufacturing process can
be used to produce steam. This steam can then be used to drive a turbine to generate electricity.
What are other natural ways that can drive the turbine?
- Geothermal energy
- Biomass
- Tides
- Sunlight
- Wind
How can tides drive the turbine?
When the tide comes in, the water is trapped in a reservoir and then let out past turbines
Why arent there many tidal stations?
There are not many tidal power stations in the world because of the difficulty of finding suitable locations.
How can waves drive the turbine?
Waves can be used to generate electricity too. In one type of wavepower generating station, the up-and-down movement of the water drives a piston connected to a generator.
How can wind be used to generate electricity?
Wind energy can be harnessed to turn a shaft
The amount of electricity a single windmill can generate is limited, but a number of wind-powered generators can be connected together in “wind farms” to produce larger amounts of electrical energy
How can sunlight be used to generate electricity?
In 1839, French scientist Alexandre Edmond Becquerel soaked two metal plates in an electricity-conducting solution. When he exposed one of the plates to sunlight, he was able to detect a small voltage.
Unfortunately, the voltage from his invention was too small to be useful as a source of power
Silicon-based solar cells are much more
efficient at producing current
What is the disadvantage of batteries?
However, large banks of batteries are rarely used because they are expensive and bulky
What is the disadvantage of rechargable batteries?
Rechargeable batteries are widely used to provide backup power for emergency lights and computer systems.
However, these batteries produce electricity only after they have been charged using electricity from an external source.
Since rechargeable batteries are never 100% efficient, they actually use more electricity than they produce
fuel cells
A fuel cell generates electricity directly from a chemical reaction with a fuel such as hydrogen
nonrenewable
resource
it cannot be replaced as it is used up
Alberta’s other fossil fuel
resources are also nonrenewable. Crude oil (petroleum), and natural gas
will eventually run out.
renewable resources
can be renewed or replenished
naturally in relatively short periods of time. Some are continually replenished
Wind energy, tidal energy, solar energy, geothermal energy, and biomass are resources that naturally renew themselves,
