BTU Meters/Flow Meters

Tim McElwain

what is your experience with these devices? Have any of you used the ONICON?

MikeyB

BTU Meters

We have them (Onicon) in one of our Commercial high rise in Times Square,  for Tenant  Chill Water & Hot Water heating  BTU Metering, and had the flow meters one our Electric Drive Chillers and dual fired Absorption machines as well ,  alot of problems on start up, (not the meters fault) such as not being installed properly, teflon tape jamming up the impeller, solder balls, brazing rods, etc, etc, a couple of them I had to cut out and reinstall/relocate for the recommended pipe diameters before and after the meter in order to get a proper reading, we had these meters hooked up to our BMS system, once they were up and running and calibrated they worked well, the tech dept was very helpful with getting us set up.

Brad White

I second Onicon

Very reliable and less cost than magnetic meters. I specify these on closed loop systems though, not open cooling systems for example. The Onicon element is a pinwheel with sapphire bearings, very smooth and range-tolerant when properly selected.



In smaller systems (say 2 inch pipe and smaller), Ista makes a good line.



As with any BTU meter though, the entire package, flow meter, cumulative flow processor and temperature sensors, are as essential. No point in hooking up a fine flow meter with drifting sensors. No point in using 10 K Ohm thermistor sensors with a 7% flow meter. All components must match in accuracy and resolution lest the errors compound beyond usefulness.

Tim McElwain

Is it necessary

to enlarge piping on either side of the flow meter?



Does it communicate with any BAS or utility systems?

Brad White

No pipe reduction usually

The Onicon F-1300 is a fixed element for smaller piping (3/4" and 1") so is self-contained.

The other models (F-1100, 1200 and FB-1200) are sized to the pipe size so no changes are required. The key is that the turbine is sized for a certain flow and velocity keyed to the range normally applied in a given pipe size. They do not produce an appreciable pressure drop.



Most other flow meters, Venturi types in particular, want to see a reduction in diameter to increase velocity and put Mssrs. Venturi and Bernouli to work.



For BAS integration, absolutely~ We use these meters for variable constant flow through chillers where the pump has to respond ahead of the chiller, fairly critical.  From the Onicon web site regarding their System 10:



Network

Compatible Serial Communications



Optional

communications card provides complete energy, flow and

temperature data through a single network connection.

Available with LONWORKS®, Johnson Controls N2,

Siemens P1, MODBUS and BACnet® interface cards.



For local representation, we use Leonhardt Associates, (Larry Leonhardt) in Wellesley, MA. I am not sure if he covers RI. But Larry has been a resource to me for over 30 years.

Tim McElwain

Thanks for the information

I am trying to help a contractor who has been asked to setup a system here in RI. I have connected him up with a local engineering firm who has done some of this we will be meeting later this week. I did not want to go into the meeting without some knowledge.



I am also looking at the Onicon web site.



My experience has been with flow meters on gas lines so this will be an interesting study. I have seen these installed and working just never had the privilege of getting in on the ground floor for installation.