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Basic EE Question (Related to Energy Consumption)

  1. Sep 15, 2014 #1
    1. The problem statement, all variables and given/known data

    You are an electrical engineer in a small manufacturing facility that uses an average energy consumption of 100 MW-hr/day to run the facility (365 days a year). Of this amount, 20% goes towards fluorescent lighting. The cost that the facility pays is costs $0.21 kW-hr. You find a small company that has developed a new switch- ing power converter for supplying energy to the fluorescent lights. The converter allows a 25% reduction in energy consumption of this type of lighting.
    (a) The facility would like to recover the costs of the project after 1 year, how much capital invest could you spend to upgrade and install the new power converters? You can ignore the effect of interest rates for the year!
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    2. Relevant equations

    3. The attempt at a solution
    I first found the total energy consumed by the facility in one year.
    Then I found the energy consumed by fluorescent light in 1 year & its cost.

    Then I found the new consumption cost of the fluorescent light. (taking into account the 25% reduction).
    I then found the TOTAL cost incurred by the facility with new config (inclusion of power converters)

    After this I am stuck. I am pretty much unable to arrive on what the question asks you to find.

    Can somebody please explain? How to go about from here?

    Thank you
  2. jcsd
  3. Sep 15, 2014 #2


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    So the cost of installing the kit (the amount that you can spend) must be less than the saving in year 1.
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