HVAC Templates - Humidity Control

Humidification

If there is humidification control check the check box and select the control type below.

Humidification control type

When humidification is selected there are 2 further options:

• 1-Constant supply humidity ratio means that during heating the supply air will always be at the Maximum heating supply humidity ratio.
• 2-Humidistat means that the humidity in the zone is controlled using the Humidification setpoint defined on the Activity tab. The ideal loads system will attempt to meet the humidistat request, i.e. it will humidify according to the setpoint.

Dehumidification control type

When dehumidification is selected there are 3 further options:

• 1-Constant supply humidity ratio means that during cooling the supply air will always be at the Minimum cooling supply humidity ratio.
• 2-Humidistat means that the humidity in the zone is controlled using the Dehumidification setpoint defined on the Activity tab. The ideal loads system will attempt to meet the humidistat request, i.e. it will dehumidify according to the setpoint.
• 3-Constant sensible heat ratio. means that the ideal loads system will be controlled to meet the sensible cooling load, and the latent cooling rate will be computed using a constant sensible heat ratio (SHR).

For 3-Constant sensible heat ratio and 2-Humidistat options, if the mixed air humidity ratio is less than the target humidity ratio, then the mixed air humidity ratio will be used. For all options, the supply air humidity ratio will never be allowed to exceed saturation at the supply dry bulb temperature. The selected dehumidification control type is always applied when the unit is in cooling mode. If the unit is in deadband mode (not actively heating the supply air) control type Humidistat will be active. If the unit is in heating mode, control type Humidistat will be active if the Humidification Control Type field below is set to Humidistat or None. This allows the ideal loads system to heat and dehumidify at the same time.