modelGenericAHU

Generic air-handling unit with heat recovery system

Information

The GenericAHU is an air-handling unit model with detailed hydraulic system of the preheater, heater and cooler. The ahu includes a heat exchanger for heat recovery and a humidifier for the supply air. The humidifier can be insert steam or water that evaporates completely (adiabatic). Further, the ahu includes an adiabatic humidifier in the return air chanal in order to cool the return air and use the heat recovery heat excahnger to cool the supply air. The preheater, steam humdifier and adiabatic humidifier are conditional and can be deactivated.

Parameters

Type	Name	Default	Description
Modelica.Units.SI.Temperature	T_amb		Ambient temperature
Modelica.Units.SI.MassFlowRate	m1_flow_nominal	1	Nominal mass flow rate in air canal
Modelica.Units.SI.MassFlowRate	m2_flow_nominal	0.5	Nominal mass flow rate in hydraulics
Modelica.Units.SI.PressureDifference	dpDamper_nominal	1	Pressure drop of fully open dampers at nominal mass flow rate
Advanced
Modelica.Units.SI.Time	tau	15	Time Constant for PT1 behavior of temperature sensors
Dynamics › Equations
Modelica.Fluid.Types.Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamics.DynamicFreeInitial	Type of energy balance: dynamic (3 initialization options) or steady state
Modelica.Fluid.Types.Dynamics	massDynamics	Modelica.Fluid.Types.Dynamics.DynamicFreeInitial	Type of mass balance: dynamic (3 initialization options) or steady state
Fans
Fluid.Movers.BaseClasses.Characteristics.efficiencyParameters	hydraulicEfficiency		Hydraulic efficiency of the fans
Advanced › Initialization
Modelica.Units.SI.Temperature	T_start	303.15	Initialization temperature
Preheater
Boolean	usePreheater	true	If true, a preaheater is used
Humidifiers
Boolean	useHumidifierRet	true	If true, a humidifier in return canal is used
Boolean	useHumidifier	true	If true, a humidifier in supply canal is used
Assumptions
Boolean	allowFlowReversal1	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium in air canal
Boolean	allowFlowReversal2	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium in hydraulics

Components

Type	Name	Description
Modelica.Fluid.Interfaces.FluidPort_a	port_a1	Fluid connector a1 (positive design flow direction is from port_a1 to port_b1)
Modelica.Fluid.Interfaces.FluidPort_b	port_b1	Fluid connector b1 (positive design flow direction is from port_a1 to port_b1)
Modelica.Fluid.Interfaces.FluidPort_a	port_a2	Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)
Modelica.Fluid.Interfaces.FluidPort_b	port_b2	Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)
RegisterModule	preheater	Preheating coil subsystem
RegisterModule	cooler	Cooling coil subsystem
RegisterModule	heater	Heating coil subsystem
Fluid.HeatExchangers.DynamicHX	dynamicHX	Heat recovery heat exchanger
Modelica.Fluid.Interfaces.FluidPort_a	port_a3	Fluid connector a3 (positive design flow direction is from port_a3 to port_b3)
Modelica.Fluid.Interfaces.FluidPort_b	port_b3	Fluid connector b3 (positive design flow direction is from port_a3 to port_b3)
Fluid.Actuators.Dampers.Exponential	flapSup	Supply air flap
Fluid.Actuators.Dampers.Exponential	flapRet	Return air flap
Fluid.Actuators.Dampers.Exponential	dampHX	Flap to heat recovery system
Fluid.Actuators.Dampers.Exponential	dampBypass	Bypass flap of heat recovery system
Modelica.Blocks.Sources.Constant	const
Modelica.Blocks.Math.Add	add
Modelica.Fluid.Interfaces.FluidPort_a	port_a4	Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)
Modelica.Fluid.Interfaces.FluidPort_b	port_b4	Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)
Modelica.Fluid.Interfaces.FluidPort_a	port_a5	Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)
Modelica.Fluid.Interfaces.FluidPort_b	port_b5	Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)
Fluid.Movers.FlowControlled_dp	fanSup	Supply air fan
Fluid.Movers.FlowControlled_dp	fanRet	Return air fan
Fluid.Humidifiers.GenericHumidifier_u	humidifier	Steam or adiabatic humdifier in supply canal
Fluid.Humidifiers.GenericHumidifier_u	humidifierRet	Adiabatic humidifier in retrun canal: cools inlet air of heat recovery system
Fluid.Sensors.TemperatureTwoPort	senTRet	Return air temperature sensor
Fluid.Sensors.TemperatureTwoPort	senTExh	Exhaust air temperature sensor
Fluid.Sensors.TemperatureTwoPort	senTSup	Supply air temperature sensor
Fluid.Sensors.TemperatureTwoPort	senTOda	Outside air temperature sensor
Fluid.Sensors.VolumeFlowRate	senVolFlo	Exhaust volume flow sensor
Fluid.Sensors.RelativeHumidityTwoPort	senRelHumSup	Supply air humidity sensor
Fluid.Sensors.RelativeHumidityTwoPort	senRelHumSup1	Return air humidity sensor
BaseClasses.GenericAHUBus	genericAHUBus	Bus connector for generic ahu
Fluid.Interfaces.PassThroughMedium	passThroughPreheater	Passthrough if without preheater
Fluid.Interfaces.PassThroughMedium	passThroughHumidifer	Passthrough if without humidifier
Fluid.Interfaces.PassThroughMedium	passThroughHumidiferRet	Passthough if without adiabtic return air humidifier

Name	Description
Medium1	Medium in air canal in the component
Medium2	Medium in hydraulic circuits

Revisions

October 29, 2019, by Alexander Kümpel:
First implementation

modelGenericAHU

Information

Parameters

Components

Contents

Revisions