modelBypassDampers
Enthalpy recovery wheel with bypass dampers
Extends from Buildings.Fluid.HeatExchangers.ThermalWheels.Latent.BaseClasses.PartialWheel (Partial model for enthalpy recovery wheel).
Information
Model of an enthalpy recovery wheel, which consists of a heat exchanger and two dampers to bypass the supply and exhaust airflow.
This model does not require geometric data. The performance is defined by specifying the part load (75% of the nominal supply flow rate) and nominal sensible and latent heat exchanger effectiveness. This operation of the wheel is configured as follows.
-
If the operating signal
uRot=true,- The wheel power consumption is constant and equal to the nominal value.
- The heat exchange in the heat recovery wheel is adjustable via bypassing supply/exhaust air through the heat exchanger. Accordingly, the sensible and latent heat exchanger effectiveness are calculated with Buildings.Fluid.HeatExchangers.ThermalWheels.Latent.BaseClasses.Effectiveness.
-
Otherwise,
- The wheel power consumption is 0.
- In addition, there is no sensible or latent heat transfer, i.e., the sensible and latent effectiveness of the heat recovery wheel is 0.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.HeatExchangers.ThermalWheels.Data.Generic | per (from PartialWheel) | Record with performance data | |
| Modelica.Units.SI.PressureDifference | dpDamper_nominal | 20 | Nominal pressure drop of dampers |
| Assumptions | |||
| Boolean | allowFlowReversal1 (from PartialWheel) | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for medium 1 |
| Boolean | allowFlowReversal2 (from PartialWheel) | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for medium 2 |
| Flow resistance › Medium 1 | |||
| Boolean | from_dp1 (from PartialWheel) | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Real | n1 (from PartialWheel) | 2 | Flow exponent, n1=1 for laminar, n1=2 for turbulent |
| Boolean | linearizeFlowResistance1 (from PartialWheel) | false | = true, use linear relation between m_flow and dp for any flow rate |
| Flow resistance › Medium 2 | |||
| Boolean | from_dp2 (from PartialWheel) | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Real | n2 (from PartialWheel) | 2 | Flow exponent, n2=1 for laminar, n2=2 for turbulent |
| Boolean | linearizeFlowResistance2 (from PartialWheel) | false | = true, use linear relation between m_flow and dp for any flow rate |
| Dynamics › Actuator position | |||
| Boolean | use_strokeTime | true | Set to true to continuously open and close valve using strokeTime |
| Modelica.Units.SI.Time | strokeTime | 120 | Time needed to fully open or close actuator |
| Modelica.Blocks.Types.Init | init | Modelica.Blocks.Types.Init.InitialOutput | Type of initialization of dampers (no init/steady state/initial state/initial output) |
| Real | yByp_start | 1 | Initial position of bypass actuators |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | P (from PartialWheel) | Electric power consumption | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | epsSen (from PartialWheel) | Sensible heat exchanger effectiveness | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | epsLat (from PartialWheel) | Latent heat exchanger effectiveness | |
| Modelica.Fluid.Interfaces.FluidPort_a | port_a1 (from PartialWheel) | Fluid connector a1 of the supply air (positive design flow direction is from port_a1 to port_b1) | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b2 (from PartialWheel) | Fluid connector b2 of the exhaust air (positive design flow direction is from port_a2 to port_b2) | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b1 (from PartialWheel) | Fluid connector b1 of the supply air (positive design flow direction is from port_a1 to port_b1) | |
| Modelica.Fluid.Interfaces.FluidPort_a | port_a2 (from PartialWheel) | Fluid connector a2 of the exhaust air (positive design flow direction is from port_a2 to port_b2) | |
| Buildings.Controls.OBC.CDL.Interfaces.RealInput | uBypDamPos | Bypass damper position | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput | uRot | True when the wheel is operating |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.Sensors.MassFlowRate | senSupMasFlo (from PartialWheel) | Supply air mass flow rate | |
| Buildings.Fluid.Sensors.MassFlowRate | senExhMasFlo (from PartialWheel) | Exhaust air mass flow rate | |
| Buildings.Fluid.Actuators.Dampers.Exponential | bypDamSup | Supply air bypass damper | |
| Buildings.Fluid.Actuators.Dampers.Exponential | damSup | Supply air damper | |
| Buildings.Fluid.Actuators.Dampers.Exponential | damExh | Exhaust air damper | |
| Buildings.Fluid.Actuators.Dampers.Exponential | bypDamExh | Exhaust air bypass damper | |
| Buildings.Controls.OBC.CDL.Reals.Switch | swiEpsSen | Switch the sensible heat exchanger effectiveness based on the wheel operation status | |
| Buildings.Controls.OBC.CDL.Reals.Switch | swiEpsLat | Switch the latent heat exchanger effectiveness based on the wheel operation status |
Revisions
-
September 29, 2023, by Sen Huang:
First implementation.