(when to clean)How to choose cleaning moment for the exchanger?

The precise moment to clean a heat exchanger also strongly depends on the costs, of course. In the figure below this is illustrated for a simple example for a heat exchanger with a linearly increasing fouling factor, thus linearly increasing energy costs. The heat exchanger is periodically cleaned offline. A cleaning operation takes a certain amount of money, so when time increases this amount per unit time will drop. The right time to clean the exchanger is when the sum of the two is at its minimum:

 

Simple example of choosing the cleaning moment