Temperature Control on Double-Pipe Heat-Exchangers: An Application

This paper begins with the development of first principles models for Heat-exchangers. The found results are then used to improve a laboratory temperature control solution for a dual mode Heat-exchanger apparatus. In particular, the co-current and counter-current transfer functions are obtained from the partial differential equations that explain the heat balances for both, cold and hot fluid traveling through the pipes. The Pole-Zero maps are also depicted from the transfer functions for further dynamical analysis. Finally the PID control for the laboratory apparatus, which can work in both co- and counter-current mode, is presented along with some preliminary results. The hot water recycle control scheme for the laboratory apparatus and the adoption of the PID solution is justified by the number and location of poles and zeros found near in the origin vicinity, after beeing calculated for the open-loop transfer function.