Re: [TRNSYS-users] PID control parameters

Thanks! Is there a cooling tower component in the HVAC/TESS library which does this?

Regards,

Suhrid

From: TRNSYS-users [trnsys-users-bounces@lists.onebuilding.org] on behalf of Ben Heymer [bheymer@gmail.com]
Sent: Wednesday, July 15, 2015 5:12 PM
To: TRNSYS users mailing list at OneBuilding.org
Subject: Re: [TRNSYS-users] PID control parameters

A typical HVAC energy model runs with time steps of a few minutes, whereas real PID controllers usually operate on a timescale of seconds. So you may get better performance out of the iterative controller to emulate the behavior of a real PID controller. Or better yet, use a cooling tower type that is able to solve for fan speed as a function of desired outlet temperature instead of one that strictly takes fan speed as an input.

-Ben Heymer

On Wed, Jul 15, 2015 at 3:32 PM, Suhrid A Deshmukh <suhrid@mit.edu> wrote:

Hello,

I am trying to control the temperature of the water leaving the cooling tower to 18C. I am simulating an years worth of data and the simulation timestep in 10 min. I am trying to use the PID controller to do this. i am setting the setpoint variable in the PID controller to 18C and the controlled variable as the temperature of the water exiting the cooling tower. I was wondering what kind of Gain constant and integral time (derivative time can be zero) should I use to get the optimal performance.

Regards,

Suhrid

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