Key Reports and Graphs
To stay close to my system, I continuously monitor and track a variety of information in reports and variables in graphs.
You can run reports on many points and if you can program in Visual Basic, you can condense the data into meaningful information that you can review in a minute. In my reports I do the following:
- Calculate tonnage provided by the chiller, secondary pumps, and AHUs to find avoidable losses. For example, if the chiller is producing 200 tons, the pumps should be generating about 180 tons and the sum of the AHUs should be equal to some 150 tons.
- Create a report that provides a weekly occupancy schedule for every room. Use this information to monitor rooms with their dampers open 100% or above an upper limit. Also use it to monitor rooms that are off when they are scheduled to be on and vice versa.
It takes time to scan report information for deviations, so I built a table summary for quick reference. The table lines up significant AHU parameters (OAT, outside air damper, return air damper, fan speed, setpoints, etc.) so I can quickly spot changes in any of the parameters.
I also plot variables continuously in graphs. Typically I monitor the last four hours, but if necessary I can stretch a graph back to its beginning. Once a week I save all the data, close the graph, and start a new one. The graphs display the big picture, and if something happens, I know when it happened and can match it to maintenance or other events. The variables that I plot include:
- Tower fan speed, supply water, and return water
- Chiller power consumption, water temperatures supplied and returned, and gallons per minute (gpm)
- Water supplied to and returned from building (gpm)
- Power consumption
- Heating and cooling tons for the building.
You can also plot the air handler parameters until you fully understand their cycles though the day and night.