modelSimpleHouse6

Free cooling model
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Extends from SimpleHouse5 (Heating controller model).

Information

For this last exercise, we first increase the window size from 2 m2 to 6 m2.

We will add a ventilation model that allows to perform free cooling using outside air when solar irradiation heats up the room too much. The system consists of a fan, a damper, a controller with an air temperature setpoint between 23°C and 25°C, and a heat recovery unit with a constant effectiveness of 85%. The damper and fan have a nominal pressure drop/raise of 200 Pa. The heat recovery unit has a nominal pressure drop of 10 Pa at both sides. The nominal mass flow rate of the ventilation system is 0.1 kg/s.

Required models

Connection instructions

Connect the components such that they exchange mass (and therefore also energy) with the MixingVolume representing the zone air. Add a boundary_pT to draw air from the environment. Enable its temperature input and connect it to the TDryBul variable in the weather data reader. Also reconsider the nominal mass flow rate parameter value in the MixingVolume given the flow rate information of the ventilation system. Finally, make sure that the fan is only active when the damper is open.

Reference result

The figures below show the results.

Air temperature as function of time.

Ventilation control signal as function of time.

Parameters

TypeNameDefaultDescription
Modelica.Units.SI.AreaAWall (from SimpleHouse0)100Wall area
Modelica.Units.SI.LengthdWall (from SimpleHouse0)0.25Wall thickness
Modelica.Units.SI.ThermalConductivitykWall (from SimpleHouse0)0.04Wall thermal conductivity
Modelica.Units.SI.DensityrhoWall (from SimpleHouse0)2000Wall density
Modelica.Units.SI.SpecificHeatCapacitycpWall (from SimpleHouse0)1000Wall specific heat capacity
Modelica.Units.SI.AreaAWin (from SimpleHouse2)2Window area
Modelica.Units.SI.VolumeVZone (from SimpleHouse3)8*8*3Zone volume
Modelica.Units.SI.MassFlowRatemAir_flow_nominal (from SimpleHouse3)1Nominal mass flow rate for air loop
Modelica.Units.SI.CoefficientOfHeatTransferhWall (from SimpleHouse3)2Convective heat transfer coefficient at the wall
Booleanuse_constantHeater (from SimpleHouse4)trueTo enable/disable the connection between the constant source and heater and circulation pump
Modelica.Units.SI.HeatFlowRateQHea_flow_nominal (from SimpleHouse4)3000Nominal capacity of heating system
Modelica.Units.SI.MassFlowRatemWat_flow_nominal (from SimpleHouse4)0.1Nominal mass flow rate for water loop
Modelica.Units.SI.PressureDifferencedpAir_nominal200Pressure drop at nominal mass flow rate for air loop

Connectors

TypeNameDefaultDescription
Buildings.BoundaryConditions.WeatherData.BusweaBus (from SimpleHouse0)Weather data bus

Components

TypeNameDefaultDescription
Buildings.BoundaryConditions.WeatherData.ReaderTMY3weaDat (from SimpleHouse0)Weather data reader
Buildings.HeatTransfer.Sources.PrescribedTemperatureTOut (from SimpleHouse0)Exterior temperature boundary condition
Modelica.Thermal.HeatTransfer.Components.HeatCapacitorwalCap (from SimpleHouse1)Thermal mass of wall
Modelica.Thermal.HeatTransfer.Components.ThermalResistorwalRes (from SimpleHouse1)Thermal resistor for wall: 25 cm of rockwool
Modelica.Blocks.Math.GaingaiWin (from SimpleHouse2)Gain for solar irradiance through the window
Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlowwin (from SimpleHouse2)Very simple window model
Modelica.Thermal.HeatTransfer.Components.ThermalResistorconRes (from SimpleHouse3)Thermal resistance for convective heat transfer
Buildings.Fluid.MixingVolumes.MixingVolumezon (from SimpleHouse3)Very simple zone air model
Buildings.Fluid.HeatExchangers.Radiators.RadiatorEN442_2rad (from SimpleHouse4)Radiator
Buildings.Fluid.HeatExchangers.HeaterCooler_uheaWat (from SimpleHouse4)Heater for water circuit
Fluid.Movers.Preconfigured.FlowControlled_m_flowpum (from SimpleHouse4)Pump
Buildings.Fluid.Sources.Boundary_pTbouWat (from SimpleHouse4)Pressure bound for water circuit
Modelica.Blocks.Sources.ConstantconHea (from SimpleHouse4)Gain for heater
Modelica.Blocks.Sources.ConstantconPum (from SimpleHouse4)Gain for pump
Modelica.Blocks.Math.BooleanToRealbooRea1 (from SimpleHouse5)Boolean to integer
Modelica.Blocks.Math.BooleanToRealbooRea (from SimpleHouse5)Boolean to real
Modelica.Blocks.Logical.HysteresishysRad (from SimpleHouse5)Hysteresis controller for radiator
Modelica.Blocks.Logical.Notnot1 (from SimpleHouse5)Negation for enabling heating when temperature is low
Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensorsenTemZonAir (from SimpleHouse5)Zone air temperature sensor
Buildings.Fluid.Actuators.Dampers.ExponentialvavDamDamper
Buildings.Fluid.Movers.Preconfigured.FlowControlled_dpfanConstant head fan
Buildings.Fluid.HeatExchangers.ConstantEffectivenesshexRecHeat exchanger for heat recuperation
Buildings.Fluid.Sources.Boundary_pTbouAirAir boundary with constant temperature
Modelica.Blocks.Logical.HysteresishysAirHysteresis controller for damper
Modelica.Blocks.Math.BooleanToRealbooRea2Boolean to real
Modelica.Blocks.Math.BooleanToRealbooRea3Boolean to real
Buildings.Fluid.Sensors.TemperatureTwoPortTFanInTemperature at fan inlet
Buildings.Fluid.Sensors.TemperatureTwoPortTFanOutTemperature at fan outlet

Revisions

  • August 5, 2024, by Hongxiang Fu:
    Added two-port temperature sensors to replace sta_*.T in reference results. This is for IBPSA #1913.
  • September 4, 2023, by Jelger Jansen:
    First implementation.