A heat engine takes in heat from a furnace at a rate of 105M

A heat engine takes in heat from a furnace at a rate of 105MW, and it rejects waste heat into the ocean at a rate of 60MW. For this heat engine, calculate

1. The net power output

2. The thermal efficiency

Solution

Since the input heat and ouput heat are given as rate of input heat and rate of output heat, The net power output of the power plant can be obtained from W net,out=Qin-Qout. In place of work , this equation gives us the net power output (Power is work done per unit time)

1.Net power output,P=Rate of heat entering the furnace - Rate of heat leaving the furnace

=105-60

=45MW

2.Thermal Efficiency=P/Qin=45/105=0.4285