Answer to Question #309445 in Mechanical Engineering for Jhonny

Question

5. A steam condenser receives 10 kg/s of steam with an enthalpy of 2570 KJ/kg. steam condenses into a liquid and leaves with an enthalpy of 160 KJ/kg. Cooling water, passes through the condenser with temperature increases from 13 degrees C to 24 degrees C. Calculate the water flow in kg/s.

Answer 1

Solution;

Steam change in enthalpy;

$\Delta u=2570-160=2410kJ/kg$

The amount of heat lost form the steam is the heat gained by the cooling water,given by;

$Q=\dot{m}\Delta h$

$Q=10×2410=24100kJ/s$

Heat gained by water is;

$Q=\dot{m_w}C\Delta T$

Where;

$C=4182J/kg°C$

Therefore;

$\dot{m_w}=\frac{Q}{C×\Delta T}$

$\dot{m_w}=\frac{24100}{4182×(24-13)}$

$\dot{m_w}=0.5239kg/s$