Air-air conditioning systems. Air handling unit, constant flow all-air system with double duct
Dual-duct systems have two supply ducts, one for cold air and one for warm air. The terminal units are mixing boxes to which both ducts lead. For constant air flow systems, the fan is a fixed speed fan. Regulation is achieved by mixing air from both ducts in the terminal units (mixing boxes). The fans will always be running.
Air handling unit, constant flow all-air system with double duct. “Air conditioning” tab
Cooling (optional)
- Cooling coil (Cold water)
This sets the characteristics of the cooling coil:- Cold water
- Chilled-water system
Allows users to select a chilled-water system defined in the "Air conditioning systems" section.
- Chilled-water system
- Advanced configuration
- Automatic sizing options
- Design supply temperature
- Automatic sizing options
- Cold water
Heating (optional)
- Heating coil (Direct expansion / Electric / Gas)
Sets the characteristics of the heating coil:- Hot water
- Hot-water system
Allows users to select a hot-water system defined in the "Air conditioning systems" section.
- Hot-water system
- Electric
- Gross rated capacity (optional)
- Gas
- Gross rated capacity (optional)
- Advanced configuration
- Gas heating coil efficiency
- Parasitic electric load
- Advanced configuration
- Automatic sizing options
- Design supply temperature
- Automatic sizing options
- Hot water
Supply fan
- Advanced configuration
- Working hours (Always on / Only with active ventilation)
- Automatic air flow calculation (Simultaneous / Total)
- Single fan
- Main fan
- Motor efficiency
- Motor heat losses fraction in air stream
- Maximum air flow rate (optional)
- Specific power
- Main fan
- Dual fan
- Cooling duct fan
- Motor efficiency
- Motor heat losses fraction in air stream
- Maximum air flow rate (optional)
- Specific power
- Heating duct fan
- Motor efficiency
- Motor heat losses fraction in air stream
- Maximum air flow rate (optional)
- Specific power
- Cooling duct fan
Air handling unit, constant flow all-air system with double duct. “Outdoor air inlet” tab (optional)
If the “Outdoor air inlet” tab is deactivated, the system only recirculates air from the heating zones.
Free cooling (optional)
Heat recovery (optional)
- Sensible effectiveness
- Latent effectiveness (optional)
- Advanced configuration
- Heat exchanger type (Plate / Rotary)
- Frost control type (None / Exhaust air recirculation / Exhaust only / Minimum exhaust temperature)
Return fan (optional)
- Specific power
- Advanced configuration
- Motor efficiency
- Motor heat losses fraction in air stream
Air handling unit, constant flow all-air system with double duct. “Humidity control” tab
Dehumidification (optional)
The dehumidification of the air is carried out by its cooling and subsequent reheating.
- Relative humidity setpoint
- Control zone
The control zone is that which contains the thermostat associated with this equipment. A zone that contains a terminal unit connected to this equipment must be selected.
Humidification with steam (optional)
- Relative humidity setpoint
- Control zone
The control zone is that which contains the thermostat associated with this equipment. A zone that contains a terminal unit connected to this equipment must be selected. - Steam flow, nominal
- Humidifier rated electric power (optional)
