Calculating BTU

[hmlhwl]

Hello,

Has any one tried calculating BTU through DDC Logic? There is Temperatures sensor in the supply and return and a flow meter in the Chilled Water line. Any inputs on the best way to do it through programming in DDC logic and experience will be helpful.

[MatrixTransform]

Hello,

Has any one tried calculating BTU through DDC Logic? There is Temperatures sensor in the supply and return and a flow meter in the Chilled Water line. Any inputs on the best way to do it through programming in DDC logic and experience will be helpful.

Flow x Cp x td...more or less

[kontrolphreak]

Accurate sensors (matched temperature).

kontrol out

[NickDeal]

Hello,

Has any one tried calculating BTU through DDC Logic? There is Temperatures sensor in the supply and return and a flow meter in the Chilled Water line. Any inputs on the best way to do it through programming in DDC logic and experience will be helpful.

There's a lot to doing that. Different control systems have different issues doing things like this. JCI for instance might not calculate the value in a known time frame. Depending on what is going on in the system and whether you are using a controller or LCT. Siemens can do it in a somewhat known time frame or you can force it to calculate at least every second. If you are not time sensitive I would use the El Goog and figure out what it would take for your system.

[digo]

http://hvac-talk.com/vbb/showthread....-on-CHW-System

[clogic]

$.02 :

Calculations offered are for water. Glycol has different specific gravity, which affects the BTU calculation.

I also tie a status point (flow / no flow) to stop the calculation to avoid value windup when not flowing.

John

[acddc]

Wanna keep it simple try this product.

http://www.onicon.com/?gclid=CKOg2snRkr4CFdDm7AodmSAAZA

Rock solid reputation!