Re: [TRNSYS-users] problem with differential controller

[Oriol Casal via TRNSYS-users <trnsys-users@lists.onebuilding.org>]

Hi Amirreza,

I am no expert but I would try to run the simulation with a much smaller timestep. Furthermore if the collectors have no thermal capacitance this control system is likely to be unstable and oscillate. Try using a temperature from the tank into the controller.

Regards

Oriol Casal

On Apr 29, 2017 09:36, "Amirreza Heidary via TRNSYS-users" <trnsys-users@lists.onebuilding.org> wrote:

Dear All

I'm using a 5 collectors in series with a differential controller to turn on the pump when the difference of collector outlet and inlet temperatures is more than 5 and turn it off when it is less than 2.But the signal and collector output temperatures are fluctuating too much, also the signal is not compatible with temperature variations.as you can see in the following diagram, the signal is 1 when the outlet temperature is at maximum ! 

(red line is collector outlet temperature and orange line is the controller signal)

 

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amirrezaheidary

master student of energy systems Engineering

Sharif university of technology

Tehran-Iran

E-mail address:

heidari@energy.sharif.edu

amirrezaheidarysbu@gmail.com

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