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Copyright 2020 - NICHOLAS A. CHAZAPIS

Operating Trend Logs:


a. Trend logging is a feature that allows recording of selected parameters at preset intervals of time. The feature can be used to log the value of parameters such as temperatures, flow rates, electrical power, and cooling demand. The recording interval can be set from one minute to about two hours.

b. The trend data can be used for various functions, ranging from trouble shooting to identifying energy saving opportunities.

c. An example of the usefulness of the trend logging feature in BAS when it shows the trend data for chilled water supply temperature, which indicates that it exceeds the set point temperature after 12:00 noon, while another trend shows that the condenser water supply temperature exceeds the maximum design value after 11 a.m. indicating that the high condenser water temperature may be the cause of the chillers not being able to meet the chilled water temperature set point.

d. The trend logging feature can also be used for trouble shooting by trending multiple parameters. For example, if a chiller frequently trips, trending of related operating parameters, such as condenser water and chilled water flows and temperatures, may help to identify the cause as low flow or high condenser water temperature.