Abstract
This paper presents a systematic synthesis method that considers multiple shells and logarithmic mean
temperature difference (LMTD) FT correction factor for heat exchanger networks (HENs) involving multiple
periods of operation. The approach adopted entails firstly generating a reduced multiperiod HEN superstructure
using network solutions obtained when the STEP (Stream Temperature Versus Enthalpy Plot) and HEAT (Heat
Allocation and Targeting) synthesis methods are applied to each subperiod. The second stage entails
generating an initial multiperiod HEN solution from the reduced superstructure synthesis approach. The number
of shells, as well as the FT correction factor, required by each exchanger in each period of the initial multiperiod
HEN are then manually calculated and used to initialise the multiperiod HEN to obtain updated representative
heat exchanger areas for all stream pairs in all periods of operations. The solution obtained, when the method
of this paper is applied to a literature example, shows that the assumption of 1 – 1 (1 shell pass – 1 tube pass)
design configuration for multiperiod HEN problems, underestimates the representative heat exchanger areas
by 12.3%.