Question

A steam pipe for a 300-m-tall building receives superheated steam at 200 kPa at ground level. At the top floor the pressure is 125 kPa, and the heat loss in the pipe is 110 kJ/kg. What should the inlet temperature be so that no water will condense inside the pipe?

Answer 1

Answer:

inlet temperature is $170^{\circ}C$be so that no water will condense inside the pipe

Explanation:

Assumptions,

• No change in the kinetic energy
• Steady state

• single inlet and exit flow

The energy equation is given by

$q+h_i=h_e+gZ_e$

No condensation  means

$h_{e}=h_{g} \text { at } 125k P a=2685.4 \mathrm{kJ} / \mathrm{Kg}$

$h_i=h_e+gZ_e-q$

Substituting the values,

=$2685.4+\frac{9.807 \times 300}{1000} -(-110)$

=$2685.4+\frac{2942.1}{1000} -(-110)$

=$2685.4+ 2.9421 -(-110)$

=$2685.4+ 2.9421 + 110$

=2798.34 kJ/kg

At 200 kPa T$\sim$ 170