## A Targeting Procedure: The Problem Table Algorithm

The composite curves discussed earlier can be used to set energy targets, however, they can be inconvenient as they rely on graphical construction. Linnhoff and Flower [26] have developed a method of calculating energy targets algebraically, which is referred to as the ‘Problem Table’. The procedure is as follows:
1. Select a global ΔTmin for the calculation.
2. Convert the actual stream temperatures Tact into shifted temperatures Tshift by subtracting half the minimum temperature difference from the hot stream temperatures, and by adding half to the cold stream temperatures:
Hot streams:

$Tshift=Tact−ΔTmin2$

(16-14)

Cold streams:

$Tshift=Tact+ΔTmin2$

(16-15)

The use of the shifted temperature ...

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