The heater temperature of the ideal heat engine is 500K, the temperature of the refrigerator is 400K.

The heater temperature of the ideal heat engine is 500K, the temperature of the refrigerator is 400K. Determine the efficiency of the cycle and the net power if the heater transmits 1675J / s.

To find the efficiency of the considered cycle of the machine and the useful power, we will use the formulas: η = 1 – Тх / Тн and N = (Qн – Qх) / t = (Qн – Qн * (1 – η)) / t.
Variables: Тн – machine heater temperature (Тн = 500 К); Тх – refrigerator temperature (Тх = 400 K); Qн – heat from the heater (Qн = 1675 J); t – cycle time (t = 1 s).
Calculation: a) η = 1 – Тх / Тн = 1 – 400/500 = 0.2 (20%);
b) N = (Qн – Qн * (1 – η)) / t = (1675 – 1675 * (1 – 0.2)) / 1 = 335 W.
Answer: The cycle efficiency is 20%; the net power is 335 W.