Topic 8. Energy Production
Power Plant Basics
In a power plant: burn fuel produces heat flows into combustion
chamber. To control pressure, we have the exhaust. Most energy flows into
the boiler (heat exchanger) with water. As water boils, pressure increases.
Steam towards the turbine as the turbine rotates, attached coils rotate
and as they are in a Magnetic Field, electricity is produced in the generator.
Other side of the turbine must have low pressure steam. It is cooled with
water in the condenser, turning the steam back into water which is then
pumped–with a pump–into the boiler.
Start with chemical/nuclear energy, converted into heat energy. This makes
steam that has kinetic energy, and the turbine is also kinetic energy. Output
is electric energy. From 100J, about 15J are lost as exhaust energy, 50J as
waste heat in the condenser, and 5J as friction from the turbine and pump.
Joules
Energy density: energy per unit volume | 3
meters
Joules
Specific energy: energy per unit mass |
kilograms
Gases have low ED and high SE. Wood has low ED and SE. Coal has high
ED and low SE.
Solar, Hydro, and Wind Power
Photovoltaic cell: solar energy into electric energy.
Solar hearing panel: warms water with energy from Sun, generates heat.
Power Joules
Intensity: | 2
Area seconds ×meters
Watts
Solar Constant: Intensity of sunlight at the location of Earth. 1370
meters2
Average incident intensity may be less than the solar constant since it
varies depending on the season, time of the day, slant, etc.
Hydroelectric power: mass m falls through distance h, which exerts a force
on a turbine that produces electricity. Gravitational potential energy.
Pump storage: at nighttime, water is pumped up to a reservoir at a higher
elevation (requires energy), and at the daytime the water falls back down,
producing electricity.
Tidal power: energy from tides into power, mainly electricity.
, kg m
Δ GPE m× g × h ρ× V × g ×h 3
× m3 × 2 × m 2
Remember that Power= = = | m s kg × m
time time time =
s s3
Wind power: comes from solar energy that heats up the atmosphere, causes
pressure that drives the wind, creates KE, moves a turbine, generates
electricity. In the ideal case, the KE exiting is 0. Off-shore and in top of hills
due to high wind speeds.
2 2 3
KE m× v 2 ρ ×V × v 2 ρ ×(v × A)×v ρ ×( π ×r )×v 1
P= = = = = = Aρ v 3 |
time 2× second 2 2 2 2
3
kg 2 m
3
×m × 2 2
m s kg × m
= 3
s s
Nuclear Power
Nuclear plant is responsible for the production of heat, whereas the power
plant is responsible for the production of electricity. Fuel arranged in fuel
rods. Control rods manage the rate of reaction. Moderator surrounds the
fuel roads in the combustion chamber– it is usually water. Superheated
radioactive water must be surrounded by strong walls to prevent radiation
from leaking to the boiler. Heat must move out to the boiler. Cooler water is
pumped, by pumps, back into the chamber.
A neutron hits a nucleus of U-235, splitting it into (usually) into Baryon (Ba),
Krypton (Kr) and 3 neutrons. These nuclei have KE, and the neutrons can
cause another fission if they strike U-235. Control rods reduce the
probability that a chain effect occurs, making a sustainable reaction.
Usually made out of cadmium and barium, which are good at absorbing
neutrons, maintaining a constant rate of fission.
Power Plant Basics
In a power plant: burn fuel produces heat flows into combustion
chamber. To control pressure, we have the exhaust. Most energy flows into
the boiler (heat exchanger) with water. As water boils, pressure increases.
Steam towards the turbine as the turbine rotates, attached coils rotate
and as they are in a Magnetic Field, electricity is produced in the generator.
Other side of the turbine must have low pressure steam. It is cooled with
water in the condenser, turning the steam back into water which is then
pumped–with a pump–into the boiler.
Start with chemical/nuclear energy, converted into heat energy. This makes
steam that has kinetic energy, and the turbine is also kinetic energy. Output
is electric energy. From 100J, about 15J are lost as exhaust energy, 50J as
waste heat in the condenser, and 5J as friction from the turbine and pump.
Joules
Energy density: energy per unit volume | 3
meters
Joules
Specific energy: energy per unit mass |
kilograms
Gases have low ED and high SE. Wood has low ED and SE. Coal has high
ED and low SE.
Solar, Hydro, and Wind Power
Photovoltaic cell: solar energy into electric energy.
Solar hearing panel: warms water with energy from Sun, generates heat.
Power Joules
Intensity: | 2
Area seconds ×meters
Watts
Solar Constant: Intensity of sunlight at the location of Earth. 1370
meters2
Average incident intensity may be less than the solar constant since it
varies depending on the season, time of the day, slant, etc.
Hydroelectric power: mass m falls through distance h, which exerts a force
on a turbine that produces electricity. Gravitational potential energy.
Pump storage: at nighttime, water is pumped up to a reservoir at a higher
elevation (requires energy), and at the daytime the water falls back down,
producing electricity.
Tidal power: energy from tides into power, mainly electricity.
, kg m
Δ GPE m× g × h ρ× V × g ×h 3
× m3 × 2 × m 2
Remember that Power= = = | m s kg × m
time time time =
s s3
Wind power: comes from solar energy that heats up the atmosphere, causes
pressure that drives the wind, creates KE, moves a turbine, generates
electricity. In the ideal case, the KE exiting is 0. Off-shore and in top of hills
due to high wind speeds.
2 2 3
KE m× v 2 ρ ×V × v 2 ρ ×(v × A)×v ρ ×( π ×r )×v 1
P= = = = = = Aρ v 3 |
time 2× second 2 2 2 2
3
kg 2 m
3
×m × 2 2
m s kg × m
= 3
s s
Nuclear Power
Nuclear plant is responsible for the production of heat, whereas the power
plant is responsible for the production of electricity. Fuel arranged in fuel
rods. Control rods manage the rate of reaction. Moderator surrounds the
fuel roads in the combustion chamber– it is usually water. Superheated
radioactive water must be surrounded by strong walls to prevent radiation
from leaking to the boiler. Heat must move out to the boiler. Cooler water is
pumped, by pumps, back into the chamber.
A neutron hits a nucleus of U-235, splitting it into (usually) into Baryon (Ba),
Krypton (Kr) and 3 neutrons. These nuclei have KE, and the neutrons can
cause another fission if they strike U-235. Control rods reduce the
probability that a chain effect occurs, making a sustainable reaction.
Usually made out of cadmium and barium, which are good at absorbing
neutrons, maintaining a constant rate of fission.
