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Flashcards in Reversed heat engines Deck (6)
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1

examples of reverse heat engines simply 

heat pump, and refigerators

 

 

2

how do reverse heat engines work

  • operate between hot and cold resivoirs like any other engines
  • difference is direction of energy transfer
    • heat energy taken from cold resivoir and trasnferred to the hot resivoir 
  • heat naturally flows from hotter to colder spaces
    • work must be done

3

refrigerators

  • aims to extract as much heat energy from the cold space as possible for each joule of work done
  • the cold space is the inside of the refrigerator whilst the ht space is the room
  • refrigerators keep enclosed spaces cool that can be used to store perishable food fresh for longer

 

 

4

heat pump

  • aims to pump as much heat as possible into the hot space per joule of work done
  • cold space usualyl outdoors
  • hot space is inside of house
  • used to heat rooms and water

 

 

5

Coefficient of performance

  • describes how well work is converted into heat transfer

6

what is the max theoretical  efficiency for the coefficent of performance for a fridge and a heat pump

  • COPref = TC / (TH - TC)
  • COPhp =TH / (TH - TC)