[TRNSYS-users] Simulation result delay

[Jeff Thornton]

Don’t forget about the mass of the building.  Does your cooling equipment have the capacity to meet the load quickly?  Without studying it, it looks like the capacity is limited and it takes a while on those days when it starts further from the setpoint to get up to the setpoint.  On those days where it starts close to the setpoint everything is fine.  

Jeff - TESS

Sent from my iPhone

> On May 6, 2022, at 8:53 AM, Huijie Pu via TRNSYS-users <trnsys-users at lists.onebuilding.org> wrote:
> 
> 
> Hi,
>       I made a simple VAV air conditioning system for a single room, controlling the room temperature at 26 degrees and the supply air temperature at 16 degrees. The control time of PID and each component is from 8:00 to 18:00 every day, simulations are the indoor temperature and supply air temperature and the air volume of the room from August 1st to 6th, but the simulation result shows a control delay, when the simulation time the longer it is, the more accurate the subsequent simulation can control at 8 o'clock, just like the temperature change on August 6 in the picture. During the first half of the simulation on August 1, the room temperature was lower than the control temperature by 26 degrees, and then the room temperature was higher than the control temperature, and a control signal appeared to stabilize the temperature at 26 degrees. But in the days since, the control signal has advanced every day, until accurate control appears at 8 o'clock. Although I found that the appearance of this control signal is related to the room temperature, when I only simulated the temperature on August 6th, I found that the simulation results were the same as the current August 1st results, or only Control appears in the latter half of the time. I don't know what is the reason for this problem?
> 
> kind regards,
> 
> Pu
> 
> 
>  
> 
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