Air-Standard Cycle

Working fluid:

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Reversed Brayton Cycle:

Assumptions:

P-v and T-s Diagram:

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Control Volume:

First Law of Thermodynamics:

Second Law of Thermodynamics:

Pressure ratio: r=P2P1

Temperature Specific Volume
12 T2=T1rγ1γ v2=v1r1γ
34 T4=T3rγ1γ v4=v3r1γ

Work:

Specific Work
Compressor wcomp=CpT1[1rγ1γ]
Expander wexp=CpT3[1rγ1γ]
Net wnet=CPT1[(1rγ1γ)+T3T1(1rγ1γ)]

Heat:

Specific Heat
Intake qin=CPT1[1T3T1rγ1γ]
Exhaust qout=CPT1[T3T1rγ1γ]

Coefficient of Performance:

In laymans terms, β=what we wantwhat we give. This is not an Efficiency!

β=qin|wnet|=1rγ1γ1

Results:

Example: