Dehumidification control, maximum of deviation heating (DhuCtl12)
Overview
The application function "Dehumidification control 12, maximum of deviation heating for dehumidify" (DhuCtl12) lowers room relative humidity in heat pump applications by overriding the heating/cooling coil valve position for cooling and setting the fan to the correct speed for dehumidification.
Function
The PID controller compares the room relative humidity to the setpoint that corresponds to the active plant mode. The PID-Control mode is set to 2-Pos (Off/Dehumidify) to enable max power to quickly lower the temperature for dehumidification.
In addition, the room temperature is monitored. Dehumidification control is disabled if the room temperature falls below the present heating setpoint minus a configurable differential (Max.deviation heating for dehumidify, HDvnMaxDhu).
The table shows default values for dehumidification setpoints and parameters per plant mode. Dehumidification is enabled during Comfort and Pre-Comfort, and disabled during Economy and Protection. (see Configuration)
Plant mode | DhuCtl | Setpoint for dehum. [%] |
|---|---|---|
Off | Off | - |
Protection | Off | 70 |
Economy | Off | 70 |
Pre-Comfort | On | 60 |
Comfort | On | 60 |
For other plant modes, dehumidification values are either predefined or dependent on the configuration settings.
DhuAvl: Signal to indicate heat pump heating/cooling coil is available for dehumidification
DhuReq: Signal to override heat pump heating/cooling coil
Configuration
Objects
Description | Object | Type | Default value |
|---|---|---|---|
Relative room humidity setpoint for comfort | SpHuRelRCmf | ACnfVal | 60 [% r.h.] |
Relative room humidity setpoint for pre-comfort | SpHuRelRPcf | ACnfVal | 60 [% r.h.] |
Relative room humidity setpoint for economy | SpHuRelREco | ACnfVal | 70 [% r.h.] |
Relative room humidity setpoint for protection | SpHuRelRPrt | ACnfVal | 70 [% r.h.] |
Parameters
Description | Parameter | Default value |
|---|---|---|
Comfort configuration 0:Off | CmfCnf | 1:Dehumidify |
Pre-Comfort configuration Enumeration see CmfCnf | PcfCnf | 1:Dehumidify |
Economy configuration Enumeration see CmfCnf | EcoCnf | 0:Off |
Protection configuration Enumeration see CmfCnf | PrtCnf | 0:Off |
Maximum deviation heating for dehumidification | HDvnMaxDhu | 3 [K] |
Hysteresis for max.deviation heating for dehumidification | HysHDvnMaxDhu | 1 [K] |
Temperature difference unit | TDiffUnit | [K] |
Interface
Interface | Description | Type | Ref. | Owned by |
|---|---|---|---|---|
PrSpDhu | Present dehumidification setpoint | APrcVal | ● | - |
DhuCtr | Dehumidification controller | Controller | ● | - |
RCtl | Room control | GrpMaster | ◉ | Room |
SpHuRelRCmf | Relative room humidity setpoint for comfort | ACnfVal | ● | - |
SpHuRelRPcf | Relative room humidity setpoint for pre-comfort | ACnfVal | ● | - |
SpHuRelREco | Relative room humidity setpoint for economy | ACnfVal | ● | - |
SpHuRelRPrt | Relative room humidity setpoint for protection | ACnfVal | ● | - |
Engineering and commissioning
None