modelCoolingAndHeating
Active beam unit for heating and cooling
Extends from Buildings.Fluid.HeatExchangers.ActiveBeams.Cooling (Active beam unit for cooling).
Information
This model is identical to Buildings.Fluid.HeatExchangers.ActiveBeams.Cooling, except that an additional water stream and convector is added to allow for heating in addition to cooling.
For a description of the equations, see the User's Guide.
Performance data are available from Buildings.Fluid.HeatExchangers.ActiveBeams.Data.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | homotopyInitialization (from Cooling) | true | = true, use homotopy method |
| Integer | nBeams (from Cooling) | 1 | Number of beams in parallel |
| Nominal condition | |||
| Data.Generic | perCoo (from Cooling) | Performance data for cooling | |
| Data.Generic | perHea | Performance data for heating | |
| Assumptions | |||
| Boolean | allowFlowReversalWat (from Cooling) | true | = true to allow flow reversal in water circuit, false restricts to design direction (port_a -> port_b) |
| Boolean | allowFlowReversalAir (from Cooling) | true | = true to allow flow reversal in air circuit, false restricts to design direction (port_a -> port_b) |
| Dynamics › Nominal condition | |||
| Modelica.Units.SI.Time | tau (from Cooling) | 30 | Time constant at nominal flow (if energyDynamics <> SteadyState) |
| Flow resistance | |||
| Boolean | from_dpWat (from Cooling) | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Real | nWat (from Cooling) | 2 | Flow exponent for water-side, nWat=1 for laminar, nWat=2 for turbulent |
| Real | nAir (from Cooling) | 2 | Flow exponent for air-side, nWat=1 for laminar, nWat=2 for turbulent |
| Boolean | linearizeFlowResistanceWat (from Cooling) | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaMWat (from Cooling) | 0.1 | Fraction of nominal flow rate where flow transitions to laminar |
| Dynamics › Conservation equations | |||
| Modelica.Fluid.Types.Dynamics | energyDynamics (from Cooling) | Modelica.Fluid.Types.Dynamics.DynamicFreeInitial | Type of energy balance: dynamic (3 initialization options) or steady state |
| Initialization › Cooling | |||
| MediumWat.AbsolutePressure | pWatCoo_start (from Cooling) | MediumWat.p_default | Start value of pressure |
| MediumWat.Temperature | TWatCoo_start (from Cooling) | MediumWat.T_default | Start value of temperature |
| Advanced | |||
| MediumWat.MassFlowRate | mWat_flow_small (from Cooling) | 1E-4*abs(perCoo.mWat_flow_nominal) | Small mass flow rate for regularization of zero flow |
| MediumAir.MassFlowRate | mAir_flow_small (from Cooling) | 1E-4*abs(perCoo.mAir_flow_nominal) | Small mass flow rate for regularization of zero flow |
| Advanced › Diagnostics | |||
| Boolean | show_T (from Cooling) | false | = true, if actual temperature at port is computed |
| Initialization › Heating | |||
| MediumWat.AbsolutePressure | pWatHea_start | pWatCoo_start | Start value of pressure |
| MediumWat.Temperature | TWatHea_start | TWatCoo_start | Start value of temperature |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | watCoo_a (from Cooling) | Fluid connector watCoo_a (positive design flow direction is from watCoo_a to watCoo_b) | |
| Modelica.Fluid.Interfaces.FluidPort_b | watCoo_b (from Cooling) | Fluid connector watCoo_b (positive design flow direction is from watCoo_a to watCoo_b) | |
| Modelica.Fluid.Interfaces.FluidPort_a | air_a (from Cooling) | Fluid connector air_a (positive design flow direction is from air_a to air_b) | |
| Modelica.Fluid.Interfaces.FluidPort_b | air_b (from Cooling) | Fluid connector air_b (positive design flow direction is from air_a to air_b) | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heaPor (from Cooling) | Heat port, to be connected to room air | |
| Modelica.Fluid.Interfaces.FluidPort_a | watHea_a | Fluid connector a (positive design flow direction is from watHea_a to watHea_b) | |
| Modelica.Fluid.Interfaces.FluidPort_b | watHea_b | Fluid connector b (positive design flow direction is from watHea_a to watHea_b) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| MediumWat.ThermodynamicState | staWatCoo_a (from Cooling) | MediumWat.setState_phX(watCoo_a.p, noEvent(actualStream(watCoo_a.h_outflow)), noEvent(actualStream(watCoo_a.Xi_outflow))) | Medium properties in port watCoo_a |
| MediumWat.ThermodynamicState | staWatCoo_b (from Cooling) | MediumWat.setState_phX(watCoo_b.p, noEvent(actualStream(watCoo_b.h_outflow)), noEvent(actualStream(watCoo_b.Xi_outflow))) | Medium properties in port watCoo_b |
| MediumAir.ThermodynamicState | staAir_a (from Cooling) | MediumAir.setState_phX(air_a.p, noEvent(actualStream(air_a.h_outflow)), noEvent(actualStream(air_a.Xi_outflow))) | Medium properties in port air_a |
| MediumAir.ThermodynamicState | staAir_b (from Cooling) | MediumAir.setState_phX(air_b.p, noEvent(actualStream(air_b.h_outflow)), noEvent(actualStream(air_b.Xi_outflow))) | Medium properties in port air_b |
| Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlow | heaToRoo (from Cooling) | Heat tranferred to the room (in addition to heat from supply air) | |
| Modelica.Units.SI.PressureDifference | dpWatCoo (from Cooling) | watCoo_a.p - watCoo_b.p | Pressure difference watCoo_a minus watCoo_b |
| Modelica.Units.SI.PressureDifference | dpAir (from Cooling) | air_a.p - air_b.p | Pressure difference air_a minus air_b |
| FixedResistances.PressureDrop | res (from Cooling) | Flow resistance on air-side | |
| MediumWat.ThermodynamicState | staHea_a | MediumWat.setState_phX(watHea_a.p, noEvent(actualStream(watHea_a.h_outflow)), noEvent(actualStream(watHea_a.Xi_outflow))) | Medium properties in port watHea_a |
| MediumWat.ThermodynamicState | staHea_b | MediumWat.setState_phX(watHea_b.p, noEvent(actualStream(watHea_b.h_outflow)), noEvent(actualStream(watHea_b.Xi_outflow))) | Medium properties in port watHea_b |
| Modelica.Units.SI.PressureDifference | dpWatHea | watHea_a.p - watHea_b.p | Pressure difference between watHea_a and watHea_b |
Revisions
-
June 14, 2016, by Michael Wetter:
Revised implementation. -
May 20, 2016, by Alessandro Maccarini:
First implementation.