Maximum efficiency of a heat engine

AI Thread Summary
The maximum efficiency of a heat engine using surface lake water at 19°C and rejecting waste heat at 4.1°C is calculated using the formula eta = 1 - Tc / Th. The temperatures must be converted to Kelvin, resulting in Tc = 277.1K and Th = 292K. An initial calculation yielded an incorrect efficiency of -0.945548 due to a misapplication of the formula. The error was identified as incorrectly treating the equation, leading to confusion about the conversion process. Proper application of the equation will yield the correct efficiency value.
JJones_86
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Homework Statement


Calculate the maximum possible efficiency of a heat engine that uses surface lake water at 19°C as a source of heat and rejects waste heat to the water 0.100 km below the surface where the temperature is 4.1°C.


Homework Equations


eta = 1 - Tc / Th


The Attempt at a Solution



eta = 1 - 277.1K/292K
eta = -.945548


Not sure what I'm doing wrong, am I not supposed to convert to Kelvin??
 
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Nevermind, I've figured out what I did wrong, I was treating the equation like this (1-277.1K)/292K
 

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