Typically used in office buildings, hotels, high end residential buildings. Central Outdoor-Air Handling Unit provides 100% of Outside Air to the zone meaning all air that is going through the unit is only the Outside Air, there is no mixing with the return air. All exhaust air from the zones goes to the Heat Recovery unit where Outside Air that we are introducing to the building is preheated or precooled depending on the season.

If heat recovery effectiveness is zero that practically means that DOAS doesn’t have the heat recovery. If “Design Air Flow” for the “Central Outdoor-Air Handling Unit” is zero that practically means that there is no “Central Outdoor-Air Handling Unit”.

User decides on how much outside air will be supplied to the building. This is done via “Design Air Flow” slider.

Default values:

• Hot Water Pump power(if system is water-cooled): 21 W/gpm or 1.32 W/(L/s)
• Condenser Water Pump power (if system is water-cooled): 21 W/gpm or 1.32 W/(L/s)
• Fan Coil Fan Power: 0.2 W/cfm or 0.095 W/(L/s)
• DOAS Fan Power: 0.64 W/cfm or 0.3 W/(L/s)
• Minimum Outdoor Temperature in Cooling Mode: -6C
• Maximum Outdoor Temperature in Cooling Mode: 43C
• Minimum Outdoor Temperature in Heating Mode: -25C
• Maximum Outdoor Temperature in Heating Mode: 35C
• Minimum Outdoor Temperature in Heat Recovery Mode: -15C
• Maximum Outdoor Temperature in Heat Recovery Mode: 45C
• Minimum Heat Pump Part-Load Ratio: 0.15   
• Maximum Outdoor Dry-bulb Temperature for Crankcase Heater: 5C
• Defrost Strategy: Resistive
• Defrost Control: Timed
• All pumps are VSD
• Night time operation: Cycle on any load