[TRNSYS-users] What is the purpose of Type 11d? (Controlled Flow Mixer)

[Jeff Thornton]

Adrian,

There are uses for this mode but they are a bit sublime.  An experienced user could take the control signal and connect it to the pumps or flow sources such that the inlet flows sum to the desired outlet flow.  But my point has always been that if I know the control signal already, I would feed it to two diverting valves, one for each flow, then use the appropriate outputs from those diverters into one mixing valve.  Or use the known signal to drive two pumps ( Y and 1-Y) and use a mixing valve.  But as a 30-year  TRNSYS user I’ll admit I’ve never used that mode.  I’ve seen some people use it as a tempering valve but I much prefer the tempering controllers in the TESS Libraries.  

Jeff 

Sent from my iPhone

> On May 30, 2020, at 2:08 PM, Adrian Riebel Brummer via TRNSYS-users <trnsys-users at lists.onebuilding.org> wrote:
> 
> 
> 
> Dear TRNSYS users,
> 
> I would like to ask how is the Controlled flow mixer (Type 11d) supposed to be used. In the explanation about the control signal (one of the inputs of the component) there is this equation:
> 
> mdot,out = mdot,in,1*(1-Y) + mdot,in,2*Y
> 
> Y is the control signal. Sincerely I don't see a physical explanation for this valve, because the outflow is not the sume of the two inlet flows. Where does the rest of the fluid go? The valve has only one outlet flow (given by the equation above) and one outlet temperature.
> 
> Regards,
> 
> Adrian Riebel
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