#218 secondaryLoop and primaryLoop tags

Denis OConnor Mon 13 Oct 2014

I propose the following tags:

secondaryLoop discharge temp sensor

secondaryLoop return temp sensor

secondaryLoop mixed temp sensor

primaryLoop discharge temp sensor

primaryLoop return temp sensor

primaryLoop mixed temp sensor

The descriptions use the following drawing for a location reference "http://e3-az.com/e3-CP-piping.htm"

The tag names are modeled after the AHU tags and allow us to calculate the % of primaryLoop flow entering the secondaryLoop in a similar way we calculate % outside air at the AHU with the familiar formula: % Outside Air Fraction = (MAT-RAT)/(OAT-RAT).

The percent of primaryLoop flow entering the secondaryLoop = (secondaryLoop mixed temp-secondaryLoop return temp)/(primaryLoop discharge temp - secondaryLoop return temp).

"secondaryLoop discharge temp sensor" is located on the discharge side of the pumps as shown by the "CHWS temperature" sensor.

"secondaryLoop return temp sensor" is located as shown by the "CHWR temperature" sensor.

"secondaryLoop mixed temp sensor" is located on the suction side of the secondary loop pumps. It is not shown on the referenced drawing and may have the same problems of inadequate mixing as the MAT on the air handler does because it may not be located far enough from the "Common" Tee to provide good mixing.

"primaryLoop discharge temp sensor" is located by the "CHWS Temp" reference at a place that ensures good mixing.

"primaryLoop return temp sensor" is located by the "ECW Temperature" reference. It is located far enough from the "Common" Tee to provide good mixing.

"primaryLoop mixed temp sensor" is also located by the "ECW Temperature" reference but may be not be located far enough from the "Common" Tee to provide good mixing.

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