how to check the HVAC Availability Schedule of a zone program

Replies to This Discussion

Permalink Reply by Mostapha Sadeghipour Roudsari on August 28, 2015 at 2:06am

Hi Grasshope,

I'm not sure if there is a different HVAC Availability schedule based on program types. As you can see the availability schedule is set to Always On which means whenever that zone needs cooling or heating the HVAC will be available. In this case system will be used based on set-points and not the schedule. You can plot cooling loads and heating loads and any hour that the loads are not 0 it means the system has been on.

Mostapha

Permalink Reply by Chris Mackey on September 7, 2015 at 10:34am

Grasshope,

Mostapha said it all and I just want to confirm that all of the zone programs use a HVAC availability schedule of ALWAYS ON whenever you set the conditioning of the zones to true.  I added in the availability schedule on the Set EP Zone Schedules component just to give you an extra level of control over the system if you want it.

-Chris

Permalink Reply by Ding on November 4, 2015 at 2:08am

Hi Chris and Mostapha,

Can I make a customized schedule for the HVAC system based on both the "occupancy Schedules" and the "set points"? It means the HVAC system will turn on only when two conditions are fulfilled simultaneously: 1)there is people in space; 2) the indoor temperature is lower the heating set point (or higher the cooling set point).

Is that correct if I did it according to the attached image (to achieve what I describe above) ?

Thank you very much in advance!

Best,

Ding

Permalink Reply by Ding on November 4, 2015 at 3:14am

PS: What I concerned is whether the setpoints will be ignored if I make a customized schedule for the HVAC system.

Permalink Reply by Mostapha Sadeghipour Roudsari on November 4, 2015 at 6:18am

Yes. If the HVAC is not available at any time-step then setpoints will be ignored. You can connect occupancy schedule directly to HVACAvailability but make sure that values are normalized to 0-1 as occupancy have cases with partial occupancy.

Mostapha

Permalink Reply by Chris Mackey on November 4, 2015 at 8:23pm

Ding,

For simulations with the "Run Simulation component", the HVAC will only turn on when the space is outside the setpoints so there is not need to include this in the schedule.  Just plug in the occupancy schedule as Mostapha says.

-Chris

Permalink Reply by Max D on June 29, 2016 at 8:35am

I had a recent error with the set EP zone schedules component- the HVAC availabiltiy schedule input got randomly replaced with a "Ventilation Schedule" input upon updating via the Update HBee component to a more recent version (despite the fact that the machine install was directly from GitHub, about a month ago).

Not sure what's loading from where, but would be worth checking? Which one is the more recent?

m

Permalink Reply by Chris Mackey on June 29, 2016 at 6:50pm

Max D,

The change in the schedule component was intentional.  HVACAvailablity is now going to be set with the new AirDetails component for OpenStudio Systems.  In other words, HVAC Availability will be set at the HVAC level instead of the zone level.

I will post more information on the workflow at the next stable release in a few weeks but I attached an example file showing the workflow to hold you over for the time being.

-Chris

Attachments:

• Adding New Systems5.gh, 541 KB