Interpreting BAS Trendlogs

[acpetri6920]

I found some other useful information here so I decided to join the site. I am a graduate student working on trendlogging data from an Alerton BAS system. This is part of my job as a research assistant not for a class homework assignment. I have been gathering data for nearly two months, but I'm not sure exactly how to interpret the findings.

Can anyone suggest some reading material or a web site that might provide some guidance?

Most appreciated,

pete

[HVAC9900]

Tough question to answer, not knowing how the trends were set up,and for what purpose.

Assuming the trends are for HVAC system info.
If that is correct, the trends points should be identified on the trend itself,especially so if you are looking at the front end.
All depends on the original program though.

What are you trending?

[NormChris]

If you do not have a solid foundation in systems knowledge the trends will be meaningless to you. As stated by HVAC9900, it depends upon what is trended and for what purpose and then to what kind of a system it is applied to.

Trends on an economizer mean something totally different from trends on a VAV box which mean something totally different from trends on a multizone package unit or a single path cooling system with reheat for humidity control. There are many dozens of possibilities.

Gee, you can even trend other trends or trend a totalization or put trends on alarms if you like.

[Carnak]

I would agree that you need a bit of understanding on how the air handler system and VAV boxes work, but more importantly you need a good background in HVAC on a whole.

I will typically log exactly what an air handler or two will do every minute and then have up to 30 data loggers I can deploy in the space to track temp-rh-dew point and a few that allow me to record co2-temp-rh-dew point and even foot candles. 30 is overkill and a lot of info to process, solved a lot of problems with just a few loggers.

If you can interpret the tea leaves it can be very lucrative. Basically look for re-occuring problematic patterns, find out what causes them- solve problem that could have been festering for years while all kinds of money has been unsuccessfully thrown at the problem without success.