A water-cooled engine produces 1589 W of power. Water enters the engine block at 14.61 °C and exits at 29.91 °C. The rate of water flow is 147.3 L/h. What is the engine’s efficiency?
To calculate the engine's efficiency, we need to determine the amount of heat supplied to the engine and the power output of the engine.
First, let's calculate the heat supplied to the engine:
The specific heat capacity of water is approximately 4.18 J/g°C. We can convert the water flow rate to grams per second:
147.3 L/h * (1000 mL / 1 L) * (1 g / 1 mL) * (1 h / 3600 s) = 40.92 g/s
Next, we can calculate the change in temperature:
ΔT = (29.91°C - 14.61°C) = 15.3°C
Now, we can calculate the heat supplied:
Q = mcΔT
= (40.92 g/s) * (4.18 J/g°C) * (15.3 °C)
≈ 2516.6 J/s
Next, let's calculate the power output of the engine:
Power output = 1589 W
Finally, we can calculate the engine's efficiency:
Efficiency = (Power output / Heat supplied) * 100%
= (1589 W / 2516.6 W) * 100%
≈ 63.1%
Thus, the engine's efficiency is approximately 63.1%.