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 T_{0}, 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.