Trouble controlling temperatures with VRF System.

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From the figure, the cooling (26.6) and heating (20) set point temperatures are not maintained. This would indicate undersized equipment. check the size of the cooling/heating coils with respect to the zone loads. You can report the coil part-load ratio and determine if the coil is running at full capacity. Also report the zone sensible load and compare to the maximum coil capacity at times when the zone temperature set point is not met.

Add these report variables to your input file and run the simulation again. Then review the results in the variables (csv) file. Use the wildcard asterisk (*) to report all data in the simulation. Add a key name (e.g., "zone name" for zone air system sensible heating rate or "coil name" for cooling coil runtime fraction) to limit the reports to specific data or systems.

Actual energy transfer rate to the zone through the zone inlet nodes:

Output:Variable,*,Zone Air System Sensible Heating Rate,timestep; !- HVAC Average [W]

Output:Variable,*,Zone Air System Sensible Cooling Rate,timestep; !- HVAC Average [W]

Actual zone predicted loads where the zone temperature set point is met IF this load is met by the HVAC system:

Output:Variable,*,Zone Predicted Sensible Load to Heating Setpoint Heat Transfer Rate,timestep; !- HVAC Average [W]

Output:Variable,*,Zone Predicted Sensible Load to Cooling Setpoint Heat Transfer Rate,timestep; !- HVAC Average [W]

Runtime fractions of the coils:

Output:Variable,*,Cooling Coil Runtime Fraction,timestep; !- HVAC Average []

Output:Variable,*,Heating Coil Total Heating Rate,timestep; !- HVAC Average [W]

Output:Variable,*,Heating Coil Total Heating Energy,timestep; !- HVAC Sum [J]

Output:Variable,*,Heating Coil Runtime Fraction,timestep; !- HVAC Average []

Part-load ratio and runtime fraction of the outdoor condensing unit:

Output:Variable,*,VRF Heat Pump Part Load Ratio,timestep; !- HVAC Average []

Output:Variable,*,VRF Heat Pump Runtime Fraction,timestep; !- HVAC Average []