HVAC tab in model data - Compact HVAC
The Fan coil unit Compact HVAC option simulates a 4 pipe fan coil unit with hot water heating coil, chilled water cooling coil, and an outside air mixer. The fan coil units are zone equipment units which are assembled from other components. Fan coils contain an outdoor air mixer, a fan, a simple heating coil and a cooling coil. The fan coil unit is connected to a hot water loop (demand side) through its hot water coil and to a chilled water loop (demand side) through its cooling coil. The unit is controlled to meet the zone (remaining) heating or cooling demand. If there is a heating demand, the cooling coil is off and the hot water flow through the heating coil is throttled to meet the demand. If there is a cooling demand from the zone, the hot water coil is off and the chilled water flow through the cooling coil is throttled to meet the load.
You can model Fan coil unit systems with or without outside air. If you include Mechanical ventilation with your Fan coil unit system then heating and cooling will only operate when the Mechanical ventilation operation schedule is on.
If you do not want to include outside air in your system, you should uncheck the Mechanical ventilation 'On' check box. In this case heating/cooling availability is determined entirely from the heating/cooling operation schedules under the Heating and Cooling headers.
Unlike the Unitary multizone and CAV and VAV Compact HVAC types, Fan coil unit zone systems take all their data from the zone level.
Note 1: EnergyPlus fan coil supply fans run continuously at full speed whenever the availability schedules are > 0 so fan coil outside air flow can be 'fully on' or 'fully off' but cannot reduce to fractional values in between. You may therefore get higher outside air delivery rates than with other
The system availability schedule can be defined to control the overall operation of the HVAC system, including heating, cooling and ventilation. This schedule is used at the zone level for Fan coil units.
You can also open headers to enter HVAC details where they are different from those loaded from the template: