Patent ID: 7110906

Claim:
A system for monitoring the performance of a heat exchanger having hot and cold legs through which hot and cold fluids flow, respectively, said hot leg having a hot inlet and a hot outlet and said cold leg having a cold inlet and a cold outlet, said system comprising: a communication link; a plurality of field devices connected to the heat exchanger and operable to measure operating values of the heat exchanger and to transmit the operating values over the communication link, said operating values including the temperature of the hot fluid at the hot inlet (T HOT-IN ), the temperature of the hot fluid at the hot outlet (T HOT-OUT ), the temperature of the cold fluid at the cold inlet (T COLD-IN ) and the temperature of the cold fluid at the cold outlet (T COLD-OUT ); a computer connected to the communication link; a software program operable to run on the computer to execute a sequence of instructions including: (a.) performing a training operation comprising: (a1.) receiving baseline sets of the operating values of the heat exchanger from the communication link; (a2.) calculating baseline values of a performance factor (E) for the baseline sets of the operating values, respectively; and (a3.) storing the baseline values of E and the baseline sets of the operating values they correspond to; (b.) after the training operation, receiving a current set of the operating values from the communication link; (c.) calculating a current value of E for the current set of the operating values; (d.) retrieving a baseline value of E for a baseline set of the operating values that substantially matches the current set of the operating values; and (e.) comparing the current value of E to the retrieved baseline value of E to obtain a measure of any change in performance of the heat exchanger; and wherein E provides a measure of the performance of the heat exchanger and is calculated using T HOT-IN , T HOT-OUT , T COLD-IN and T COLD-OUT .