Estimate the maximum efficiency of a thermodynamic engine that is powered by this temperature difference in moderate climate conditions (the living organism is the hot reservoir and the environment is the cold reservoir). take the temperature of the human body about 37∘c and assume a temperature of 8 ∘c for the environment.

The maximum efficiency of this thermodynamic engine is η=0.78

Explanation:

The maximum efficiency of a thermodynamic engine is consequence of the Maximum Work Theorem, and corresponds to a Carnot Cycle.

The expression is given by

where is the temperature of the cold reservoir, and is the temperature of the hot reservoir, therefore

is the maximum efficiency of this thermodynamic engine.

* It should be noted that a Carnot Cycle is not possible in real engines, it is a theoric tool that allows the development of the thermodynamic engines.

the answer is definitely c.

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