HVAC Thermostat Problem

asked 2024-02-07 12:18:01 -0600

updated 2024-02-12 07:34:42 -0600

Hi everyone!

I have set an HVAC system in OpenStudio (Packaged Rooftop VAV with PFP Boxes and Reheat) which has both cooling and heating electric equipment. I have also set Space Thermostat Cooling/Heating Setpoints, attached in the same thermal zone. The problem is that in a winter day, when thermal zone reaches heating setpoint temperature (for ex. 20 C degrees) and gets above it, I see that cooling node operates (even though cooling setpoint is at 27 C degrees). On the other side, in a summer day when temperature falls below cooling setpoint (ex 27 C degrees), heating node operates too. I have checked availiability managers, but they have static temperatures which are useless for me. I need also to set a temperature gap for about 1-2 degrees, before HVAC turns on again.

Thank you!

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@fotiskoz if you only have the packaged rooftop VAV providing heating/cooling, then both heating & cooling coils may need to operate in order to deliver their outlet temperatures defined by setpoint managers. For example, if the cooling coil is after the outdoor air mixing system, it may need to cool the mixed air down to a setpoint temperature before the heating coil would then heat up air to a different setpoint temperature.

The best way to know is if you can share your model via URL to Dropbox, Google Drive, etc.

Aaron Boranian's avatar Aaron Boranian  ( 2024-02-12 07:37:10 -0600 )edit