[EnergyPlus_Support] Dual setpoint with deadband control and FanAndCoilAvailSched

["Dominique Chow" <deepseafoam@xxxxxxxxxxx>]

Hi, there,
I have a question about the example file :CVBnRh.idf.
It's a constant volumn system with single setpoint control, and fans and 
coils and baseboards are available(FanAndCoilAvailSched) during occupied 
time. Location and weather I changed to Phoenix, July 20th.
under this input, the room air temperature is about 37 degree C before 
occupied.

Then, I changed the FanAndCoilAvailSched to always on. and found:

1.if still using single setpoint control, the room air temperature profile 
looks like 31 degree (before occupied), about 24 degree (occupied), and 
about 31 degree (after occupied), but the plant cooling demand as well as 
the chiller power consumption profile looks the same shape!( high chiller 
power during unoccupied time, lower chiller power during occupied time) 
instead of zero during unoccupied time and some chiller power during 
occupied time.

2.if changed to dual setpoints with dead band control with the setpoints 
during unoccupied time is 15 C for heating and 35 C for cooling, it has the 
same shape of chiller output profile as above.

3.if keep the dual setpoints control in 2. but change the baseboard control 
to be unavailable during unoccupied time, the chiller profile will look 
better: lower chiller power during unoccupied time, higher chill power 
during occupied time. the room air temperature is about 19 C before 
occupied.

I thought the chiller power before occupied period should be near zero in 
the above 3 cases. Maybe in case 1, since it's single setpoint control and 
baseboard is available,too during unoccupied time, both the baseboard and 
chiller will work to keep the air temperture to be near the setpoint(35 C), 
and thus chiller power consumes a lot. But in case 2,and 3 I don't think the 
chiller should perform like this. to make sure, in case 2 and 3, I tried 
also to set the cooling setpoint of the dual setpoint to be 45 C, and there 
is the same problem!

I have to keep the system available during night, because maybe I want to 
precool the building in later runs. These runs are for testing purpose 
before I set precooling setpoints. But the results are just not right. Can 
anybody help me out?

Thanks!!






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