[chrisk447]

Hello,

I was wondering if anyone could explain to me how to solve a Heat exchanger network using the temperature-interval method. I am stuck on one part. Once I adjust temperatures (based on delta T_min) and rank the temperatures starting at T₀, I cannot find out how to solve for

(SUM C_h - SUM C_c)_i

for an interval. (C_h is the heat capacity of the hot stream times the mass flow rate, C_c is the heat capacity of the cold stream times the mass flow rate, and i is the interval). The streams that my book uses (Seider and Seader) seem random, and I can't figure out which streams to choose for each interval.

I think this will help.

       T^s     T^t
C1    120            T5
              235     T2
C2    180            T3
              240     T1
H1    250            T0
              150     T4
H2    240            T1
              120     T5

For interval 1 (T0-T1), only stream H1 is involved. I do not get why only stream H1 is involved as it seems that stream C2 should be involved too.

Thank you in advance for any help.