blockDefrostControl
Control block to ensure no frost limits heat flow at the evaporator
Extends from AixLib.Obsolete.BaseClasses.ObsoleteModel.
Information
Basic model for a defrost control. The icing factor is calculated in the heat pump based on functions or other models.
If a given lower boundary is surpassed, the mode of the heat pump will be set to false(eq. Chilling) and the compressor speed is set to 1 to make the defrost process as fast as possible.
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November 26, 2018 by Fabian Wüllhorst:
First implementation (see issue #577)
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | minIceFac | Minimal value above which no defrost is necessary | |
| Boolean | use_chiller | true | True if defrost operates by changing mode to cooling. False to use an electrical heater |
| Modelica.Units.SI.Power | calcPel_deFro | Calculate how much eletrical energy is used to melt ice | |
| Real | deltaIceFac | 0.1 | Bandwitdth for hystereses. If the icing factor is based on the duration of defrost, this value is necessary to avoid state-events. |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Logical.Hysteresis | iceFacGreMinHea | Check if icing factor is greater than a boundary | |
| Modelica.Blocks.Interfaces.RealOutput | Pel_deFro | Relative speed of compressor. From 0 to 1 | |
| Modelica.Blocks.Sources.BooleanConstant | conTrueNotUseChi | If ice is melted with an additional heater, HP can continue running | |
| Modelica.Blocks.Sources.Constant | constPel_deFro | Calculate how much eletrical energy is used to melt ice | |
| Modelica.Blocks.Interfaces.BooleanInput | modeSet | Set value of HP mode | |
| Modelica.Blocks.Interfaces.RealInput | nSet | Set value relative speed of compressor. Analog from 0 to 1 | |
| Utilities.Logical.SmoothSwitch | swiErr | If an error occurs, the value of the conZero block will be used(0) | |
| Modelica.Blocks.Sources.Constant | conOne | If Defrost is enabled, HP runs at full power | |
| Modelica.Blocks.Interfaces.RealOutput | nOut | Relative speed of compressor. From 0 to 1 | |
| Modelica.Blocks.Interfaces.BooleanOutput | modeOut | ||
| Interfaces.VapourCompressionMachineControlBus | sigBusHP | ||
| Utilities.Logical.SmoothSwitch | swiPel | If defrost is on, output will be positive | |
| Modelica.Blocks.Sources.Constant | conZero | If Defrost is enabled, HP runs at full power | |
| Modelica.Blocks.Logical.Hysteresis | iceFacGreMinChi | Check if icing factor is greater than a boundary | |
| Modelica.Blocks.Logical.LogicalSwitch | logicalSwitch | If a chiller is used to defrost, mode will be false | |
| Modelica.Blocks.Sources.BooleanConstant | conFalseNotUseChi | Just to omit warnings | |
| Modelica.Blocks.Sources.BooleanConstant | conTrueUseChi | Set mode to false to simulate the defrost cycle |