modelFacadeVentilationUnit
Information
Overview
This is a model for Facade Ventilation Unit (FVU), which can be used for heating, cooling and ventilation purposes. It is equipped with two speed-controlled fans, a recuperator and two air-water heat exchangers. The figure below shows a scheme of the unit.
Operation Modes
The portion of fresh air flowing through the recuperator is controlled by means of a bypass damper. The portion of extract air that is recirculated and mixed with the fresh air stream is controlled by means of a circulation damper. The mixed air stream is either heated or cooled in the air-water heat exchangers. The water flow in these heat exchangers is controlled by two-way-valves.
Actuators
All actuators receive normailized signals (0-1). The supply and exhaust air fans are table-based. A relative input signal is transformed into a mass-flow set point for a flow-controlled mover. If the exhaust air fan is not in operation, the entire air flow should be recirculated. Thus, the circulation damper should be fully opened. In that case, the fresh air flap should be closed so that no fresh air can enter the unit. The exhaust air fan has a minimum mass flow rate of 1 m³/h to make the model more stable.
References
Baranski, M., Sangi, R., Fuetterer, J., Mueller, D. (2016). An Algorithm for Stepwise Exergy-based Model Predictive Control of Building HVAC Supply Chains. 29th international conference on Efficiency, Cost, Optimisation, Simulation and Environmental Impact of Energy Systems.
- July, 2017 by Marc Baranski and Roozbeh Sangi:
First implementation.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| AixLib.Airflow.FacadeVentilationUnit.DataBase.FVUBaseRecord | fVUParam | AixLib.Airflow.FacadeVentilationUnit.DataBase.FVUBaseRecord() | Record containing the characteristic parameters of the unit |
| Modelica.Units.SI.ThermodynamicTemperature | T_start | 273.15 + 20 | Initial temperature in unit |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_b | exhaustAirConnector | Connector to the exhaust air sink | |
| Modelica.Fluid.Interfaces.FluidPort_a | freshAirConnector | Connector to the fresh air source | |
| Modelica.Fluid.Interfaces.FluidPort_a | extractAirConnector | Connector to the extract air source | |
| Modelica.Fluid.Interfaces.FluidPort_b | supplyAirConnector | Connector to the supply air sink | |
| Modelica.Fluid.Interfaces.FluidPort_b | heaterReturnConnector | Connector to the heating water sink | |
| Modelica.Fluid.Interfaces.FluidPort_a | heaterFlowConnector | Connector to the heating water source | |
| Modelica.Fluid.Interfaces.FluidPort_b | coolerReturnConnector | Connector to the cooling water source | |
| Modelica.Fluid.Interfaces.FluidPort_a | coolerFlowConnector | Connector to the cooling water source | |
| AixLib.Controls.Interfaces.FVUControlBus | fVUControlBus | Bus with controller signals |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| AixLib.Airflow.FacadeVentilationUnit.BaseClasses.SetPower | fanExhaustAir | The fan on the exhaust air side | |
| AixLib.Airflow.FacadeVentilationUnit.BaseClasses.SetPower | fanSupplyAir | The fan on the supply air side | |
| Modelica.Fluid.Sensors.Temperature | extractAirTemperature | Temperature of the extract air | |
| AixLib.Fluid.HeatExchangers.ConstantEffectiveness | heater | The heat exchanger used for heating | |
| AixLib.Fluid.HeatExchangers.ConstantEffectiveness | cooler | The heat exchanger used for cooling | |
| Modelica.Fluid.Sensors.Temperature | freshAirTemperature | Temperature of the fresh air | |
| Modelica.Fluid.Sensors.Temperature | exhaustAirTemperature | Temperature of the exhaust air | |
| Modelica.Fluid.Sensors.Temperature | coolerTemperature | Temperature of the supply air stream behind the cooler | |
| Modelica.Fluid.Sensors.Temperature | heatRecoveryTemperature | Temperature behind the recuperator | |
| Modelica.Blocks.Math.Add | oppositeOpening | Provides the relative opening of the complementary damper of the recuperator | |
| Modelica.Blocks.Sources.Constant | one | Output the Real value 1 | |
| Modelica.Fluid.Sensors.Temperature | mixAirTemperature | Temperature of the mixed circulation and fresh air streams | |
| Modelica.Fluid.System | system | ||
| AixLib.Fluid.Actuators.Valves.TwoWayQuickOpening | damperCirculationAir | Damper that controls the air stream that is recirculated | |
| AixLib.Fluid.Actuators.Valves.TwoWayQuickOpening | damperBypass | The second of two dampers that control the air flow through the recuperator | |
| AixLib.Fluid.Actuators.Valves.TwoWayQuickOpening | damperHeatRecovery | The first of two dampers that control the air flow through the recuperator | |
| Modelica.Fluid.Sensors.Temperature | heaterTemperature | Temperature of the supply air stream behind the heater | |
| AixLib.Fluid.Actuators.Valves.TwoWayQuickOpening | damperFreshAir | Can be used to disconnect the unit from fresh air source | |
| AixLib.Fluid.HeatExchangers.ConstantEffectiveness | recuperator | The heat exchanger used for recovering heat or cold from extract air stream | |
| Modelica.Fluid.Vessels.ClosedVolume | volume | Volume where the circulation air and the fresh air stream mix | |
| AixLib.Fluid.Actuators.Valves.TwoWayQuickOpening | heatingValve | Valve controlling the heating water flow into the unit | |
| AixLib.Fluid.Actuators.Valves.TwoWayQuickOpening | coolingValve | Valve controlling the cooling water flow into the unit |
Contents
| Name | Description |
|---|---|
 Water | Water Model in the system |
 Air | Air Model in the system |