Can I have any energy transfer as heat transfer that is 100% available? Explain with equation
To determine if there can be any energy transfer as heat transfer that is 100% available, we can use the concept of Carnot efficiency. Carnot efficiency is the maximum efficiency that can be achieved by a heat engine operating between two temperature reservoirs.
The Carnot efficiency (η_Carnot) is given by the equation:
η_Carnot = 1 - (T_Cold / T_Hot)
where T_Cold is the temperature of the cold reservoir and T_Hot is the temperature of the hot reservoir. Both temperatures must be in absolute units (such as Kelvin).
For a heat transfer to be 100% available, the efficiency of the heat engine extracting energy as heat must be 100%, i.e., η_Carnot = 1.
Rearranging the equation, we get:
1 = 1 - (T_Cold / T_Hot)
This equation implies that T_Cold = 0, which means the cold reservoir has to be at absolute zero temperature. In practical scenarios, achieving absolute zero temperature is not possible.
Therefore, it is not possible to have any energy transfer as heat transfer that is 100% available in real-world situations. Energy always tends to flow from a hotter object to a colder object until thermal equilibrium is reached, meaning some energy will always be lost in the process.