Thermodynamic Question

Question

An engine working on the Carnot cycle has maximum and minimum temperatures of 1370^oC and 315^oC. Determine its efficiency and the heat supply per minute when the output is 24 kW. (Ans: 64.3% , 2240 kJ/min)

Answer 1

η = 1 - T_c/T_h = 1 - (315 + 273)/(1370 + 273) = 0.642

That is 64.2% efficiency.

For the second question, convert the output to kJ/min.

P_o = 24 kW = 24 kJ/s = 24 kJ / (1/60 min) = 1440 kJ/min

P_o = ηP_i ⇒

P_i = P_o/η = (1440 kJ/min)/0.642 = 2243 kJ/min