Generic model for FCU

[AntoineGautier]

This issue tracks the development of a generic and configurable model for FCU systems.

The corresponding milestone is https://github.com/urbanopt/urbanopt-modelica/milestone/21

Modeling approach

The model should extend Buildings.Experimental.DHC.Loads.BaseClasses.PartialTerminalUnit and adopt similar modeling principles as the ones used in Buildings.Experimental.DHC.Loads.Examples.BaseClasses.FanCoil4Pipe, or (for time series load models) Buildings.Experimental.DHC.Loads.Validation.BaseClasses.FanCoil2PipeCooling and Buildings.Experimental.DHC.Loads.Validation.BaseClasses.FanCoil2PipeHeating. Especially, the model is intended to be used in conjunction with Buildings.Experimental.DHC.Loads.FlowDistribution. This requires to output the required water mass flow rate. By default the model takes the measured temperature and set point as inputs. Alternatively it takes the required heat flow rate to work with time series load models.

The water coils should be modeled using Buildings.Fluid.HeatExchangers.DryCoilEffectivenessNTU until we finalize the development of WetCoilEffectivenessNTU. Is this model directly applicable to steam coils?

The fan should be modeled using Buildings.Fluid.Movers.FlowControlled_m_flow.

Configurations

The configurations to be covered are the following.

• Cooling coil: none, CHW, change-over, DX
• Heating coil: none, HHW, steam, electric heater (this might coexist with a HHW coil but let's consider them as exclusive options for now), (DX heating not included until we address Update DX coil models to represent heating mode and reversible systems #1851)
• Fresh air inlet (to be connected to a DOAS model): none, with
• Fan motor/speed: PSC/3-speed, ECM/continuous with minimum speed
• Controls: joint modulation of coils and fans based on the temperature set point or required heat flow rate tracking (no need for a "manual" control of the fan based on an additional input connector)

EDIT: no need to consider steam for in-building heat medium.

[AntoineGautier]

This issue can be closed as building-level HVAC systems are no more a priority for URBANopt-Modelica.