Humidity
The humidity controller is used to control humidity at a certain point in the system. The humidity controller should be connected to a cooling coil. A humidity controller is not required.
|
|
Supply air humidity reset per maximum
The maximum humidity ratio at the location where this humidity controller is placed is controlled to a certain constant humidity ratio or variable humidity ratio as defined in either the constant or variable control setpoint fields.
Setpoint Control Type: This defines if the supply air humidity setpoint will be a constant value or a variable value.
Constant Control Setpoint: This is the supply air humidity setpoint if the setpoint is constant.
Variable Control Setpoint: This is the supply air humidity setpoint if the setpoint is variable.
Supply air humidity reset per single zone maximum
The humidity ratio is controlled to one particular zone on the system. The current humidity ratio in that zone is measured and the supply air humidity ratio is calculated to keep the zone humidity ratio at or below a setpoint value. Dehumidification may be necessary to maintain the humidity ratio below this value.
Control Zone: This will be the zone that the system will control the supply air humidity to. The control zones can only be selected in the project after zones have been assigned to the system. Note, in the project this field will be shown even before zones have been assigned but cannot be edited until after zones have been assigned to the system. By default, the first zone assigned to the system will be set as the control zone but any zone assigned to the system can be selected from this dropdown.
Supply air humidity reset per multizone maximum avg
The humidity ratio is controlled by multiple zones on the system. The current humidity ratio in those zones is measured and an average supply air humidity ratio is calculated to keep the zone humidity ratio between two setpoint values. Dehumidification or humidification may be necessary to maintain the humidity ratio between these values.
Minimum Humidity Ratio: The average room relative humidity ratio should remain above this value.
Maximum Humidity Ratio: The average room relative humidity ratio should remain below this value.
Supply air humidity reset per multizone maximum
The humidity ratio is controlled by multiple zones on the system. The current humidity ratio in those zones is measured and the supply air humidity ratio is calculated in order to keep all zones between two setpoint values. Dehumidification or humidification may be necessary to maintain the humidity ratio between these values.
Minimum Humidity Ratio: The room relative humidity ratio should remain above this value.
Maximum Humidity Ratio: The room relative humidity ratio should remain below this value.
Supply air humidity reset per mixed air max humidity
This control strategy is only available for DOA systems. The conditioned outdoor air humidity ratio from the DOA will be controlled such that the mixed air humidity ratio is low enough to serve the worst case room on the system. For example, if the required humidity ratio (w) for a particular hour is 60 gr/lb, the system is 80% OA and the return air humidity ratio is 90 gr/lb, the DOA should control the outdoor air to be conditioned to 52.5 gr/lb to cause the mixed air humidity ratio to equal 60 gr/lb.
(% OA/100) * (w_OA) + (1 - (% OA/100)) * (w_RA) = w_MA
(0.8 * w_OA) + (0.2 * 90 gr/lb) = 60 gr/lb
w_OA = 52.5 gr/lb
Where % OA = percent of outdoor air
w_OA = outdoor air humidity ratio after being conditioned by the DOA
w_RA = return air humidity ratio
w_MA = mixed air humidity ratio
Maximum Humidity Ratio
This is the upper limit for the conditioned outdoor air humidity ratio. If the calculated conditioned outdoor air humidity ratio is higher than this value, the program will use this value.
Minimum Humidity Ratio
This is the lower limit for the conditioned outdoor air humidity ratio. If the calculated conditioned outdoor air humidity ratio is lower than this value, the program will use this value.