Supply
Extract
Fan:ConstantVolume
Used in:
- Air Handling Unit (Constant Volume)
- Fan Coil Unit
- PTAC,
- PTHP,
- Unitary Heat Cool,
- Unitary Heat Pump
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Used in:
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This object models a constant air volume fan that is intended to operate continuously based on a time schedule. This fan will not cycle on and off based on cooling/heating load or other control signals (Ref: Fan:OnOff).
A unique auto-assigned name for the Fan. Any reference to this fan by another object will use this name.
The type of the constant volume fan is fixed as:
To change from constant volume to variable volume you most open the parent AHU dialog and change the Fan type to 1-Variable volume.
The ratio of the power delivered to the fluid to the electrical input power. It is the product of the motor efficiency and the fan efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is power delivered to the fluid (air) divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density. Must be between 0 and 1.
The pressure rise (in Pascals or ftH2O) at full flow and standard (sea level) conditions (20°C and 101325 Pa).
The required pressure rise across an AHU fan is dependent on the duct network supplied by the AHU. For example, if a duct network was sized using a constant pressure loss of 1 Pa/m and the index run of the network (route of highest pressure drop) was say 300 m and the fitting losses were say an additional 20%, the required pressure rise across the fan would be 300 x 1 x 1.2= 360 Pa.
Allows you to specify a user-defined end-use subcategory, e.g., "Central System", etc. A new meter for reporting is created for each unique subcategory (ref: Report Meter). Subcategories are also reported in the ABUPS table. If this field is omitted or blank, the fan will be assigned to the "General" end-use subcategory.
The full load air volumetric flow rate (m3/sec or ft3/min) at standard temperature and pressure (dry air at 20°C dry-bulb). EnergyPlus uses local barometric pressure to account for altitude using equation for "standard atmospheric" pressure on p 6.1 of the ASHRAE 1997 HOF (SI edition) to initialize the air systems being simulated.
p=101325*(1-2.25577E-05*Z)**5.2559
where p=pressure in Pa and Z=altitude in m
The shaft power divided by the electrical power consumed. Must be between 0 and 1.
The fraction of the motor heat that is added to the air stream. A value of 0 means that the motor is completely outside the air stream. A value of 1 means that all of the motor heat loss will go into the air stream and act to cause a temperature rise. Must be between 0 and 1.
Select the Schedule that defines whether the fan can run during a given time period. A schedule value greater than 0 (usually 1 is used) indicates that the fan can be on during a given time period. A value less than or equal to 0 (usually 0 is used) denotes that the fan is off.
HVAC,Average,Fan Electric Power[W]
HVAC,Average,Fan Delta Temp[C]
HVAC,Sum,Fan Electric Consumption[J]
This output field contains the average electricity consumption rate for the fan in Watts for the timestep being reported.
This output field contains the average rise in air temperature across the fan (outlet air temperature minus inlet air temperature) (in °C or °F)elsius for the timestep being reported.
This output field contains the electricity consumption of the fan in Joules for the timestep being reported. This output is also added to a report meter with Resource Type = Electricity, End Use Key= Fans, Group Key= System (ref. Report Meter).