How Electricity is Generated from heat?
Electricity is not created it is just energy in a different form. Newton’s Law of the conservation of energy states that “Energy can neither be created nor destroyed, it simply changes from one form to another” Today we are looking at how heat is transformed into electricity.
The heat sources can be from burning things like natural gas, coal, oil, wood, garbage, etc. The heat could come from a controlled nuclear reaction, geothermal (heat from the ground), or a solar collectors where devices reflect the sun onto an absorber that heats a fluid. Wherever the heat comes from it is used to heat a fluid, typically water in a heat exchanger. That water is heated until it boils (100° C or 212° F) and is changed into steam. When this conversion happens high pressure develops because the steam takes up a lot more space then that of the water. The steam is directed through a turbine which is basically a specialized fan blade. As the steam rushes past the turbine blades it spins them like a fan that is off sitting in the window being spun by the wind. The turbine is connected to a generator by a shaft, when the generator is spun magnets and coils of wire are being moved past one another. This pushes electrons down the wire creating a flow of electrons, or electricity.
The heat sources can be from burning things like natural gas, coal, oil, wood, garbage, etc. The heat could come from a controlled nuclear reaction, geothermal (heat from the ground), or a solar collectors where devices reflect the sun onto an absorber that heats a fluid. Wherever the heat comes from it is used to heat a fluid, typically water in a heat exchanger. That water is heated until it boils (100° C or 212° F) and is changed into steam. When this conversion happens high pressure develops because the steam takes up a lot more space then that of the water. The steam is directed through a turbine which is basically a specialized fan blade. As the steam rushes past the turbine blades it spins them like a fan that is off sitting in the window being spun by the wind. The turbine is connected to a generator by a shaft, when the generator is spun magnets and coils of wire are being moved past one another. This pushes electrons down the wire creating a flow of electrons, or electricity.
The steam that was used to spin the turbine is recycled by cooling it down until it falls below the boiling point and returns to water. This is done by passing the steam / hot water hot water at this point into and through a condenser. The condenser cools the steam / water until it is all water and sends it back to the heat ex-changer where it will be reheated and turned into steam again. This must be done because it is the expansion of the water turning into steam that make the whole process work. It only makes sense to reuse the water as it is already close to the boiling point using new cold water would only increase the amount of fuel that would be needed to heat the water.
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Review Questions
1. Can energy be created?
2. What does the heat do in the system above?
3. High pressure steam spins what part ?
4. The steam is turned back into water by what device?
5. When a generator is spun it generates what?
1. Can energy be created?
2. What does the heat do in the system above?
3. High pressure steam spins what part ?
4. The steam is turned back into water by what device?
5. When a generator is spun it generates what?
