Technically Speaking - Refrigeration Loops made easy…the Propagation Terminal

Mark Gabriel

October 10, 2006

The most common use for a Propagation Terminal in ProMax® is in a propane refrigeration loop, where the duty required by a Heat Exchanger or Process Chiller(s) is used to determine the flow rate of the refrigerant within the loop. Since this calculated flowrate will be propagated in both an upstream as well as downstream direction, at some point in the loop blocks will have composition and flowrate sent into it from both directions, which is flagged as an error even though the two values are identical. Two properties, set by the user in the Advanced Tab, are allowed to pass through. These are typically Temperature and Vapor Fraction. The composition of the refrigerant is normally set in the outlet stream of the Propagation Terminal, as this has always been the easiest place to look for it. You will only need to specify the composition once for the loop, as the loop is completely closed and no material ideally enters or leaves the loop.

Authored by Mark Gabriel - BR&E Technical Support