Question

The ocean thermal energy conversion project uses the surface water near tropical islands with a temperature of 20°C as the hot temperature reservoir, and the water at some depth, with a temperature of 5.0°C, as the cold temperature reservoir for a heat engine. What is the maximum possible efficiency of an engine running between those two temperatures?

Answer 1

Answer:

$\eta=0.0512\ or\ 5.12\%$

Explanation:

Heat engine is device operating in a continuous cycle between two reservoirs such that it transfers heat from a high temperature reservoir to a low temperature reservoir giving some work output in synchronization to Kelvin-Plank statement of the second law of thermodynamics.

Given that:

• temperature of higher temperature reservoir, $T_H=20+273=293\ K$

• temperature of lower temperature reservoir, $T_L=5+273=278\ K$

For maximum efficiency:

$\eta=1-\frac{T_L}{T_H}$

were:

$T_H\ \&\ T_L$ are the temperatures of higher temperature reservoir and lower temperature reservoir respectively.

$\eta=1-\frac{278}{293}$

$\eta=0.0512\ or\ 5.12\%$