The document discusses reversible and irreversible processes in thermodynamics. It lists examples of process cycles including heating, refrigeration, heat engines, and the Carnot cycle. It also mentions combustion and cooling of tea. The document indicates that reversible processes are ideal while irreversible processes involve losses from factors like friction, weight, non-ideal gases, and temperature differences. It presents the equations for maximum efficiency of a Carnot heat engine and notes the efficiencies of reversible and irreversible processes are less than the Carnot efficiency.

1. Ahmed Medhat - Thermodynamics 1 - ahmedhatfa@hotmail.com
Reversibility , Irreversibility

2. Ahmed Medhat - Thermodynamics 1 - ahmedhatfa@hotmail.com
PROCESS CYCLE
Heating cycle
Refrigeration cycle
Heat engine cycle
Carnot cycle
Combustion
Cooling of a cup of tee
Chemical process
Property 1
Property 2
1
2

3. Ahmed Medhat - Thermodynamics 1 - ahmedhatfa@hotmail.com

4. Ahmed Medhat - Thermodynamics 1 - ahmedhatfa@hotmail.com
losses
friction
weight
Non-
ideal air
etc
Temperature
difference

5. Ahmed Medhat - Thermodynamics 1 - ahmedhatfa@hotmail.com
Property 1
Property 2
1
2
State 1 State 2 Reversible Irreversible

6. Ahmed Medhat - Thermodynamics 1 - ahmedhatfa@hotmail.com
Reversible Irreversible
IDEAL ACTUAL
P
v
1
2
3
4
Maximum efficiency or COP
𝜼𝒄 = 𝟏 −
𝑸𝟎𝒖𝒕
𝑸𝒊𝒏
= 𝟏 −
𝑻𝟎𝒖𝒕
𝑻𝒊𝒏
𝜼𝒄 > 𝜼𝒂𝒄𝒕𝒖𝒂𝒍
𝜼𝒓𝒊𝒗 > 𝜼𝒊𝒓𝒓
Carnot Heat engine
𝑄𝐿
𝑄𝐻
𝑊𝑛𝑒𝑡

7. Ahmed Medhat - Thermodynamics 1 - ahmedhatfa@hotmail.com
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