Whether it’s new construction commissioning or existing building retro-commissioning, “commissioning” is about entire systems and their performance. Almost universally, owners’ project requirements include “effectiveness” criteria as well as “efficiency” criteria. It’s not good enough that systems provide owners’ desired temperatures, humidities, pressure relationships, air quality, etc. The systems need to do that energy efficiently.
Trend analysis, either from a direct digital control system or from portable data loggers, is a valuable commissioning tool. However, as with most tools, skill and experience are required to realize the most benefit from trend analysis. One of the subtleties of trend analysis is selecting meaningful points for analysis and comparing them side-by-side.