Comparative study of temperature control in a heat exchanger process

Abstract EN

In the present work the dy namic behavior of a plate heat exchanger (PHE) (single pass counter current consists of 24 plate s) studie d e xperimentally and theoretically to control the sy stem.

Different control strategies; conventional feedback control, classical fuzzy logic control, artificial neural network (NARMAL2) control and PID fuzzy logic control were implemented to control the outlet cold water tempe rature.

A step change was carried in the hot water flow rate whic h was considered as a manipulate d variable.

The experimental he at transfer measurements of the PHE showed that the overall heat transfe r coefficient(U) is related to the hot water flow rate(mh) by a correlation having the form: m U h 7158 .

0 11045 = In this work the PHE model was found theoretically as a first order lead and second order ove rdampe d lag while the e xperimental PHE represente d dy namically (by PRC method) as a first order with negligible dead time value.

A c omparison between the experimental and the theoretical mode l is carried out and good agreement is obtained.

The performance c riteria used for different control modes are the integral square error (ISE) and integral time-weighted absolute error (ITAE) where the ITAE gave better pe rformance.

As well as the parameters of the ste p performance of the sy stem suc h as overshoot value, settling time and rise time are used to evaluate the performance of different c ontrol strategies.

The PID fuzzy controller gave better c ontrol results of temperature rather than PI, PID and artificial neural network controller since PID fuzzy controlle r c ombine s the advantage s of a fuzzy logic controller and a PID controller.

MATLAB program version 7.10 was used as a tool of simulation for all the studie s mentioned in this work.