Air-air conditioning systems. Central ventilation system
Note:
Central ventilation systems (heat recovery unit and dedicated outdoor air system (DOAS)) only supply and temper the ventilation or primary air flow. This means that they do not have the ability to control the thermostat and overcome the thermal load of the zones. In order to supply primary air and also air-condition the rooms with the same system, one of the available air-conditioning units (all-air systems) must be defined.
Heat recovery unit
Heat exchanger
- Sensible effectiveness
- Latent effectiveness (optional)
- Advanced configuration
- Heat exchanger type (Plate / Rotary)
- Frost control type (None / Exhaust air recirculation / Exhaust only / Minimum exhaust temperature)
Fans
- Specific power
- Advanced configuration
- Maximum air flow rate (optional)
- Motor efficiency
- Motor heat losses fraction in air stream
Note:
This unit contains two identical fans, one on the intake and one on the exhaust. Only the characteristics of one of the fans must be defined.
The unit drives the total ventilation airflow defined in the spaces of the zones to which it is connected. The electrical power of its fans is calculated according to this flow rate.
The unit drives the total ventilation airflow defined in the spaces of the zones to which it is connected. The electrical power of its fans is calculated according to this flow rate.
Outdoor air bypass
- Maximum indoor temperature
- Minimum outdoor temperature
Note:
The heat recovery unit has a bypass damper that allows outside air to pass through when it is beneficial for reducing the cooling requirements. To do this, the following conditions must be met:
- The indoor temperature is greater than the maximum indoor temperature.
- The outdoor temperature is greater than the minimum outdoor temperature.
- The outdoor temperature is less than the indoor temperature.
- The indoor temperature is greater than the maximum indoor temperature.
- The outdoor temperature is greater than the minimum outdoor temperature.
- The outdoor temperature is less than the indoor temperature.
Dedicated outdoor air system (DOAS)
This air conditioner only treats primary air (ventilation air) and has no load control capability. In other words, it does not follow the zone thermostat and only tempers the outside air. It has two identical fans, supply and extract.
Cooling (optional)
- Cooling coil type (Single speed DX / Cold water)
Sets the characteristics of the cooling coil:- Single speed DX
- Gross rated sensible heat ratio
The gross rated sensible heat ratio is the ratio of the nominal sensible capacity to the gross rated capacity. - Gross rated capacity (optional)
- Nominal cooling COP
- Gross rated sensible heat ratio
- Cold water
- Chilled-water system
Allows users to select a chilled-water system defined in the "Air conditioning systems" section.
- Chilled-water system
- Single speed DX
- Advanced configuration
- Automatic sizing options
- Design supply temperature
- Temperature control
- Setpoint temperature (Design supply temperature / Outdoor air temperature reset / Scheduled)
- Automatic sizing options
Heating (optional)
- Heating coil type (Single speed DX / Hot water / Gas / Electrical)
This sets the characteristics of the heating coil:- Single speed DX
- Gross rated capacity (optional)
- Gross rated heating COP
- Hot water
- Hot-water system
Allows users to select a water heating system defined in the "Air conditioning systems" section or to enter it directly.
- Hot-water system
- Gas
- Gross rated capacity (optional)
- Advanced configuration
- Gas heating coil efficiency
- Parasitic electric load
- Electrical
- Gross rated capacity (optional)
- Single speed DX
- Advanced configuration
- Automatic sizing options
- Design supply temperature
- Temperature control
- Setpoint temperature (Design supply temperature / Outdoor air temperature reset / Scheduled)
- Automatic sizing options
Note:
The cooling temperature setpoint must be greater than the heating temperature setpoint to prevent both operations from activating simultaneously.
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)
Fans
- Specific power
- Advanced configuration
- Maximum air flow rate (optional)
- Motor efficiency
- Motor heat losses fraction in air stream
Note:
This set contains two identical fans, one at the intake and another at the extraction. Only the properties of one fan must be defined.
The equipment set discharges the total ventilation air flow that is defined for the spaces of the zones to which it is connected. The electrical power of its fans is calculated based on this flow.
The equipment set discharges the total ventilation air flow that is defined for the spaces of the zones to which it is connected. The electrical power of its fans is calculated based on this flow.
Humidity control
- Dehumidification (optional)
- Humidity ratio setpoint
- Humidity ratio setpoint (optional)
- Humidity ratio setpoint
- Steam flow, nominal
- Humidifier rated electric power (optional)
Note:
The air is dehumidified by cooling it and then reheating it, using the cold and hot water coils that have been defined in the equipment.
