20 - Question 14 - The Second Law and Carnot Engine - Posted by Kambiz Ehsani - 5/5/2018 - Solved

Is this possible to build a heat engine that works between 800 and 300 degree K and the heat transfer from the hot source Qh = 500 kJ , Ql = 187.5 kJ and produce 200 kJ? Explain your answer.

Solution:

NO beacuse: the First Law is not met here.

Qh - Ql  must be the W => this becomes 500 - 187.5 which is not equal the 200 given in the assumptions of the problem and based on the First Law this is not possible because the delta of the Q must be equal to the work created on the shaft and in this example it is not the case.