HEAT TRANSFER VS THERMODYNAMICS

1) Thermodynamics is concerned with the amount of heat transfer as a system undergoes a process from one equilibrium state to another, and it gives no indication about how long the process will take.

2) A thermodynamic analysis simply tells us how much heat must be transferred to realize a specified change of state to satisfy the transferred to realize a specified change of state to satisfy the conservation of energy principle.

3) We are normally interested in how long it takes for the hot coffee in a thermos to cool to a certain temperature, which cannot be determined from a thermodynamic analysis alone thermodynamic analysis alone.

4) Determining the rates of heat transfer to or from a system and thus the times of cooling or heating as well as the system and thus the times of cooling or heating, as well as the variation of the temperature, is the subject of heat transfer

5) Heat transfer is energy transfer due to a temperature difference in a medium or between two or more media

6) Different types of heat transfer processes are called different modes of heat transfer

7) Conduction heat transfer is due to a temperature gradient in a stationary medium or media

8) Convection heat transfer occurs between a surface and a moving Convection heat transfer occurs between a surface and a moving fluid at different temperatures

9) Radiation heat transfer occurs due to emission of energy in the form of electromagnetic waves by all bodies above absolute zero temperature

a) Net radiation heat transfer occurs when there exists a temperature difference between two or more surfaces emitting radiation energy