[TRNSYS-users] OR statement

[Jeff Thornton]

Victoria,  

I would be very careful with the second part of your OR formulation - the part about the collector outlet being greater than 60.  This can often cause non convergence issues as the temperature is above 60 without flow and then falls below 60 with flow.  This causes the control signal to oscillate and the flow to oscillate and finally ends in non convergence.  You are better off using an aquastat to watch the outlet temperature as it includes deadbands and hysteresis (on at 62 and off at 58 for example).

Send the control signal of the aquastat (cooling mode) to an equation block; let’s call that input TEMPGT60 and your ambient temperature input AMBIENT

Your equation would then be:

SIGNAL = MAX(GT(AMBIENT,34),TEMPGT60)

Jeff

Sent from my iPhone

> On Jun 21, 2022, at 8:23 AM, Victoria Sarai Amador Barraza via TRNSYS-users <trnsys-users at lists.onebuilding.org> wrote:
> 
> 
> Hello everyone,
> 
> I am looking forward how to use the or statement in the equation window. 
> 
> Lets say that I want my signal to activate when the ambien temperature is GT than 34 or the temperature out of the flat collector is GT 60°.
> How could I express this in the equation window??
> 
> Thank you 
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