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## Homework Statement

Steam flows through an uninsulated pipe at 0.5 kg/s, entering at 5 bar, 440 C and exiting at 3 bar, 320 C. How much energy is lost from the steam per hour?

## Homework Equations

Which terms in the energy eqn can drop out? I'm having trouble with that.

Is there only one W?

## The Attempt at a Solution

Starting w/ the full energy eqn:

de/dt = Q - W_ + (m_i)[u_i + (p_i)(v_i) + (v_i)^2 + g*z_i] - (m_e)[u_v + (p_e)(v_) + (v_e)^2 + g*z_e]

where Q = vol. flow rate

W = work rate

m = mass flow rate

subscript e = out

subscript i = in

v = velocity

u = specific internal energy

p = pressure

So z_i = z_e = 0

Q = mv = (0.5)(0.6548) = 0.3274?