Energy Conversion

  • Energy conversion, or energy transformation, is the process of changing one form of energy to another form.
    • Any form of energy can be transformed into another form.
      • Energy is often converted from its most available form such as chemical energy (e.g., fossil fuels) into a more useful form (e.g., electricity).
    • A series of conversions may be needed in order to convert energy into the desired form.
      • Example: Chemical energy from fuel is changed into thermal energy in a vehicle engine; then into mechanical energy of the rotating crankshaft that turns the wheels.
    • Electricity cannot be used unless it has been converted to some other form of energy.
Replace Light Bulb to Fluorescent: Example: an incandescent light bulb converts electrical energy into radiant energy in the forms of visible light and infrared radiation. The light is useful; however, the infrared radiation (heat) is wasted. Modern CFL (compact fluorescent lamp) and LED (light-emitting diode) bulbs are more efficient than incandescent bulbs because they produce the same amount of light but much less infrared radiation. A lighted incandescent bulb feels hot to the touch; whereas, a CFL or LED bulb does not.
    • In any conversion process, some energy is used because some of the original energy turns into forms that are neither wanted nor needed for the desired purpose.
    • Following the Law of Conservation of Energy, wasted energy is not lost, and it does not disappear.
      • The total amount of energy put into a conversion process equals the total amount of energy put out in all forms.
    • The efficiency of an energy conversion process equals the ratio of the amount of energy desired to the amount of energy put in.
      • Because every energy conversion wastes some energy, the efficiency ratio is always less than one.
        • Question: What is the efficiency ratio of an energy conversion that requires 400 joules of energy to produce 100 joules of useful energy? (Joules are units of energy measurement.)
          • Calculation: 100 ÷ 400 = .25
          • Answer: The energy efficiency ratio is 25%. (75% of the energy is wasted.)
Electric Engine Selective Focus: Can you see how fast the generator is spinning? Inside a power plant, a generator spins at top speed to create electricity.
  • An electrical generator is a device that converts mechanical energy into electrical energy. Following are the basic principles of an electrical generator:
    • Electric conductors such as coils of copper wire are tightly wound inside a frame.
      • The conductor and its frame are called the armature.
    • Magnets are mounted on a spinning rotor inside the armature.
    • As the magnetic field spins through the coils of copper, the electrons in the conductor are set in motion to create a flow of electric current.

Difference between source and resource :

Source: A place where one can get a valuable item. Example: A coal mine is a source of coal.

Resource: A valuable item that one uses. Example: Coal is a resource.