Stencil: Zone HVAC Stencil: Unit Ventilator
Type: UnitaryZoneEqmt
Sub Type: Four Pipe Fan Coil
Note: Requires a connection to both a hot water and chilled water loop
EnergyPlus Object - ZoneHVAC:FourPipeFanCoil
The Four Pipe Fan Coil Unit is zone equipment that contains a number of different components, including:
Cooling Coil
Heating Coil
Supply Air Fan
When the user is in the Zone HVAC Groups Diagram workspace or the Air Loops Diagram Workspace and they select a Four Pipe Fan Coil Unit component shape, the following properties will be displayed in the lower left section of the workspace.
Typically these units are small (200 – 1200 cfm) and self-contained. They are mostly used in exterior zones, usually in hotels, apartments, or offices. They may be connected to ducted outside air, or have a direct outside air vent, but they do not have outside air economizers. Units with outside air economizers are marketed (in the United States) as unit ventilators
Figure - Simergy Component Properties Table
The properties in bold are required Value Entries or selections.
Simergy automatically defines a unique name for each component. This can be changed by the user if desired.
The availability is established by selecting an available library entry from the drop down list. The source for the options listed is Libraries:Schedules:Schedule Editor:Availability Schedules (Schedule Types)
This input denotes how the unit’s output is controlled in order to meet zone heating or cooling requirement. The choices are ConstantFanVariableFlow, CyclingFan, VariableFanVariableFlow or VariableFanConstantFlow. For ConstantFanVariableFlow, the fan speed is held constant to produce a fixed air flow rate whenever the unit is scheduled on. The hot water or chilled flow rate is varied so that the unit output matches the zone heating or cooling requirement. For CyclingFan, the fan speed is chosen so that the unit capacity is greater than or equal to the heating / cooling load and the fan is cycled to match unit output with the load. For VariableFanVariableFlow both air and water flow rates are varied to match the load. For VariableFanConstantFlow, the water flow rate is at full flow and the fan speed varies to meet the load
The maximum volumetric airflow rate (m3/sec) through the fan coil unit. This is also the design, rated airflow rate of the unit.
This numerical field specifies the ratio of the low speed flow rate to the maximum supply air flow rate. Its value should be less than Medium Speed Supply Air Flow Ratio. If left blank, the default value is 0.33. Leave it blank if the capacity control method selected is not CyclingFan.
This numerical field specifies the ratio of the medium speed flow rate to the maximum supply air flow rate. Its value should be greater than the Low Speed Supply Air Flow Ratio but less than 1.If left blank, the default value is 0.66.Leave it blank if the capacity control method selected is not CyclingFan.
If the fan coil unit uses outdoor air, this field specifies the outdoor air volumetric flow rate (m3/sec). This flow rate should be less than or equal to the maximum airflow rate. A value of zero specifies no outdoor air.
The name of a schedule whose values (0.0 to 1.0) are used as multipliers to alter the outdoor air flow rate. If this field is left blank, the values will default to 1.0.
This field specifies the type of supply air fan object used by this fan coil. The supply air fan is part of the fan coil compound object. See table below for selection options source.
The name of the cooling coil component that composes part of the fan coil unit . See table below for selection options source.
The maximum cold water volumetric flow rate (m3/sec) through the fan coil unit’s cooling coil.
The minimum cold water volumetric flow rate (m3/sec) through the fan coil unit’s cooling coil.
The convergence tolerance for the control of the unit cooling output. The unit is controlled by matching the unit output to the zone demand. For units with water coils, the model must be numerically inverted to obtain a specified output. The cooling convergence tolerance is the error tolerance used to terminate the numerical inversion procedure.
The name of the heating coil component that composes part of the fan coil unit. See table below for selection options source.
The maximum hot water volumetric flow rate (m3/sec) through the fan coil unit’s heating coil.
The minimum hot water volumetric flow rate (m3/sec) through the fan coil unit’s heating coil.
The convergence tolerance for the control of the unit heating output. The unit is controlled by matching the unit output to the zone demand. For units with water coils, the model must be numerically inverted to obtain a specified output. The heating convergence tolerance is the error tolerance used to terminate the numerical inversion procedure.
| Simergy Property | Libraries Ribbon Categories | Type | Possible Sub Types |
| Supply Air Fan Name | Fans & Pumps | SupplyFan | ConstantVolume
VariableVolume OnOff ComponentModel |
| Heating Coil Name | Coils & HX Eqmt | HeatingCoilWater | CoilAirHeatingWater |
| Cooling Coil Name | Coils & HX Eqmt | CoolingCoilWater | CoilAirCoolingWaterSimple
CoilAirCoolingWaterDetailedGeometry |
EnergyPlus InputOutput Reference Unit Ventilator description
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