Unwanted heating in Apache Results
Posted: Wed Nov 09, 2016 11:57 am
I'm running a model in version 2015.2.1 which includes radiant floors modeled as explicit zones so that I can investigate the change in MRT with the addition of a radiant floor to a highly glazed space. The floor is for cooling only, so my intent is to turn off heating, and model cooling using an ApacheHVAC system so that the radiant floor zone can be controlled based on the temperature in the adjacent occupied zone.
Reviewing the results, i'm finding that there is a significant amount of heating being done in these as tracked by the Heating Plant Sensible Load variable. On most days in winter, the heating system activates when the radiant floor zone temperature approaches 21°C, and remains active until the zone reaches 24°C.
Based on the Vista manual, Heating Plant Sensible Load is defined as "Sensible heating (non-negative) supplied to the room by its Apache System room conditioning plant or ApacheHVAC room units (radiators, direct acting heaters and chilled beams)". In this model i have:
- Applied the SPACE: Void/Plenum profile which has no heating or cooling system included, and has both the heating and cooling profiles turned off
- Set the heating setpoint to -50°C for the radiant floor zones via the room conditions tab in tabular data
- Deleted the room radiant heating unit from my HVAC model (there is a radiant cooling unit which is set up to provide the radiant cooling effect of the floor
- Confirmed that the ApHVAC boiler has zero load
So with the ApSys heating turned off, and no heating system defined in ApHVAC, what else can be causing heating within these zones?
Reviewing the results, i'm finding that there is a significant amount of heating being done in these as tracked by the Heating Plant Sensible Load variable. On most days in winter, the heating system activates when the radiant floor zone temperature approaches 21°C, and remains active until the zone reaches 24°C.
Based on the Vista manual, Heating Plant Sensible Load is defined as "Sensible heating (non-negative) supplied to the room by its Apache System room conditioning plant or ApacheHVAC room units (radiators, direct acting heaters and chilled beams)". In this model i have:
- Applied the SPACE: Void/Plenum profile which has no heating or cooling system included, and has both the heating and cooling profiles turned off
- Set the heating setpoint to -50°C for the radiant floor zones via the room conditions tab in tabular data
- Deleted the room radiant heating unit from my HVAC model (there is a radiant cooling unit which is set up to provide the radiant cooling effect of the floor
- Confirmed that the ApHVAC boiler has zero load
So with the ApSys heating turned off, and no heating system defined in ApHVAC, what else can be causing heating within these zones?