Heat engines

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What do heat engines do?
They convert heat into mechanical work which is represented by the transfer of heat by two bodies/reservoirs.
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Give an equation that represents conservation of energy
q_hot +q_cold +w = 0
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What are the conventions for q_hot and q_cold
q_hot<0 ; q_cold>0
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Give the equation for the entropy of the universe when no work is extracted
∆S_univ = q_hot/T_hot + q_cold/T_cold
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Define the heat engine efficiency
The work out per unit heat ] η = -w/q_hot
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When does the maximum work occur?
When the system is reversible So when ∆S_univ = 0
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What is the relationship between q_hot, q_cold, T_cold and T_hot in a reversible system?
q_cold/q_hot = -T_cold/T_hot
7 of 8
State the equation for the maximum efficiency
η_max = q_hot +q_cold/q_hot= 1+ q_cold/q_hot = 1- T_cold/T_hot
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Other cards in this set

Card 2

Front

Give an equation that represents conservation of energy

Back

q_hot +q_cold +w = 0

Card 3

Front

What are the conventions for q_hot and q_cold

Back

Preview of the front of card 3

Card 4

Front

Give the equation for the entropy of the universe when no work is extracted

Back

Preview of the front of card 4

Card 5

Front

Define the heat engine efficiency

Back

Preview of the front of card 5
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