Question

A heat engine is supplied heat at the rate of 1700 kJ/min and gives an output of 9 kW. The thermal efficiency will be around
1. 31.76%
2. 35.76%
3. 42.85%
4. 45.85%

Answer 1

Correct Answer - Option 1 : 31.76%

Concept:

Thermal efficiency of heat engine

\({η _{thermal}} = \frac{{Power\;Output}}{{Heat\;Input}}\)

Calculation:

Given:

Heat input = 1700 kJ/min = 28.33 kW, Power output = 9 kW

\({η _{thermal}} = \frac{{Power\;Output}}{{Heat\;Input}}\)

\({η _{thermal}} = \frac{{9\;}}{{28.33}}= 0.3176\)

η = 31.76%