Stencil: Zone HVAC Stencil: Radiant CB Passive Cool
Type: Air Terminal
Sub Type: CAV_PassiveCooledBeam
Stencil: Zone HVAC Stencil: Radiant CB Active Cool
Type: Air Terminal
Sub Type: CAV_ActiveCooledBeam
Note: Requires a connection to a chilled water loop
EnergyPlus Object - AirTerminal:SingleDuct:ConstantVolume:CooledBeam
Note: The property information is the same for both components. The user can select which type with the Cooled Beam Type field.
When the user is in the Zone HVAC Groups Diagram workspace or the Air Loops Diagram Workspace and they select a Cooled Beam component shape, the following properties will be displayed in the lower left section of the workspace.
The Cooled Beam system is a mixed air-hydronic system. A central, single-duct forced-air system supplies conditioned ventilation air to the zones. Sensible cooling is done by chilled water circulating through ceiling mounted cooled beam units. Chilled water flow rate through the cooled beam units is varied to meet the zone sensible cooling load. Any dehumidification is done by the central ventilation air system. Heating is usually accomplished with hot water radiators. Thermodynamically, the cooled beam system resembles the four-pipe induction unit.
To model a typical cooled beam system the user will need to define a conventional central constant volume forced air system. This system will normally be 100% outside air delivered at a fixed supply temperature (which could be reset by schedule or by outside air temperature). On the supply side of this air loop there will be the usual central AC equipment: outside air mixer, fan, heating and cooling coil. On the zone equipment (demand) side of the loop, the chilled beams will be represented as terminal units. Additional zone equipment (such as baseboard heaters) will be needed to handle heating loads.
Although the cooled beam equipment in a zone is treated by the program as a single terminal unit, the actual installation will have multiple beams in each zone. The program (in its sizing calculation for the system) figures out how many beams of what length are needed to meet the zone design load.
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)
Two types of units are modeled: Active or Passive. In the active unit, primary air is supplied through the beam, inducing some secondary zone air into contact with the coil. This unit acts as an active convector. The passive unit is simply a passive, finned convector. Primary air is supplied through a normal diffuser.
This is the air flow rate in cubic meters per second of the supply air entering the zone. This input would normally be autosized based on the ventilation requirement
The maximum chilled water flow rate for the unit. This input would normally be autosized based on the zone design load.
The number of individual cooled beam units in the zone. Normally this unit would be autocalculated by the program based upon the previous field and the nominal flow rate for a single beam unit (set by the program to 0.07 kg/s).
Normally this will be autocalculated by the program based upon the number of beam units and the zone design sensible cooling load. 1 to 4 meters is a typical length range.
The nominal or design inlet water temperature in degrees Celsius (or Farenheit). The default is 15C.
The nominal or design outlet water temperature in degrees Celsius (or Farenheit). The default is 17C.
Surface area on the air side of the beam per unit beam length. The units are square meters per meter. The default is 5.422
For remaining property descriptions - please refer to the EnergyPlus Input Output Reference for this object.
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