Fans

Input summary:

·       Classification : Fan classification based on centrifugal or axial types

·       Centrifugal Type : The type of blade type used in a centrifugal fan. Options are AirFoil, BackwardInclined, ForwardCurved

·       Control Method : The method used to control fan flow. Options are ConstantVolume,

VariableSpeedDrive, Dampers, InletVanes and TwoSpeed.

·       Flow Capacity : The design air flow rate of the fan at design conditions

o   This building descriptor sets the 100 percent point for the fan part-load curve. This input should be at least as great as the sum of the design airflow specified for each of the thermal zones that are served by the fan system. For multiple deck systems, a separate entry should be made for each deck

·       Flow Minimum(cfm) : The lowest flow rate rated for a fan

·       Position : The position of the supply fan relative to the cooling coil

·       Modeling Method : The method used to describe the design power consumption of a fan. Software commonly models fans in three ways. The simple method is for the user to enter the electric power per unit of flow (W/cfm). This method is commonly used for unitary equipment and other small fan systems. A more detailed method is to model the fan as a system whereby the static pressure, fan efficiency, part-load curve, and motor efficiency are specified at design conditions. A third method is to specify brake horsepower at design conditions instead of fan efficiency and static pressure. This is a variation of the second method whereby brake horsepower is specified in lieu of static pressure and fan efficiency. The latter two methods are commonly used for VAV and other larger fan systems.

·       Total Static Pressure : The total static pressure drop across the fan at design conditions. The total static pressure (TSP) drop includes the pressure drop across components both internal and external to an air handler. It is important for both fan electric energy usage and fan heat gain calculations

·       Overall Fan Efficiency : The efficiency of the fan at design conditions

o   Overall fan efficiency includes belt/drive and fan efficiency, but does not include the efficiency of the fan motor

·       Motor Brake HP : The design motor shaft brake horsepower of the fan

o   The motor brake horse power is the power at the motor shaft, including fan and drive efficiencies

·       Position : The position of the supply fan motor relative to the cooling air stream. Options are InAirStream and NotInAirStream.

·       Type : Defines if the motor is open or closed

·       Nameplate HP : The nameplate HP of the fan motor

·       Pole Count : The number of pole electromagnetic windings in the motor's stator and used to assign MotorEfficiency. Poles are always paired, so PoleCount is always a multiple of 2

·       Efficiency : The efficiency of the motor serving a fan

·       Power Per Flow (Ref) (W/cfm) : The supply fan power, in Watts, per unit of flow, in CFM