DOAS - Dedicated Outside Air System
Overview
A dedicated outdoor air system (DOAS) is a complete unified unit that is designed to meet a wide range of heating, cooling, dehumidification, and ventilation requirements. These units deliver up to 100% outside air and are ideal for any variable air volume (VAV) or dedicated outdoor air system (DOAS) application.
How it Works
The turnkey system features a total enthalpy wheel that spins between two air streams while moving energy that is both latent (moisture) and sensible (heat). The enthalpy wheel, which offers up to 80% total efficiency, greatly reduces the heating and cooling capacity requirements, resulting in lower operating costs.
A DOAS is built from the ground up to save energy and reduce operational expenses. With its rare earth magnet inverter scroll compressor that terminates excessive cycling and hard starts that lead to the life of the unit being extended. It can achieve the optimal efficiency under part-load settings with the help of the latest modulating technology.
It has components for optional hot gas reheat and fully regulating refrigeration that can deliver the precise volume of air needed at the required temperature and humidity. The unit can alter its heating and cooling capacity to match the necessary load thanks to variable speed components. This provides a consistent temperature throughout the space and avoids large temperature swings often associated with single stage equipment.
We are the authorized distributors for the leading American manufacturers of DOAS units. We’ll be pleased to provide the ideal unit for your application as authorized representatives.
For a fast quote or if you have inquiries about commercial or industrial DOAS, get in touch with us.
DOAS Manufacturers
We are official representatives of the DOAS manufacturers listed below. Click the link to learn more about the manufacturers’ warranties and other information.
DOAS Control Variables
The unit can be calibrated for 100% outside air or partial recirculation, both of which can provide tempered air. When set to partial recirculation the fan operates at a constant speed, however the damper modulates the outside air intake depending on how the kitchen hood is being operated.
Custom Design Options
Depending on your needs, a custom DOAS can be made for your application’s needs, including:
Choice of Condensers
- Water source heat pump
- Air cooled
- Water cooled
Heating Options
- Electric
- Gas
- Heat pump mode
- Steam coils or hot water
Flexibility
DOAS units provide 100% OAU and are ideal for more applications. They offer larger tonnage ranges and nominal CFM than competing units.
Maintenance
Accessibility and safety are now easier than ever thanks to a hinged access door and touch-safe control panel.
Durability
Galvanized steel cabinet panels exceed 1000 hour salt spray testing and have a two-coat primer and primer-paint external finish.
Features
Listed below is the range and variations of DOAS units. Contact our official representative to find out which model is best suited for your application.
- 3 – 100 Tons Capacity
- Nominal Airflow from 500 – 22,000 CFM
- 2” Double-wall cabinet with R-13 isolated injected foam
- Hinged, Double-Walled Access Doors
- Split Direct Expansion
- 6-Row Intertwined Air Coils
- Precise CFM delivery
- Exterior unit coating with salt spray rating
- Switchable sub-cooling
- Horizontal duct configurations for side return and supply
- On/off or modulating hot gas reheat
- MERV filters
- Modulating compressors for reduced overcooling/icing of evaporator coil
- Air source, water source and air source heat pump configurations
- Modulating compressors for reduced overcooling/icing of evaporator coil
- Air source, water source and air source heat pump configurations
- On/off or modulating hot gas reheat
DOAS for Commercial Kitchens & Food Service Industry
DOAS units provide energy efficient solutions for commercial kitchens that require fresh air from outside to be tempered before entering the space, therefore vastly improving indoor air quality (IAQ).
Our industry-leading, energy-efficient Dedicated Outdoor Air Systems (DOAS) are the perfect solution for commercial kitchens that require a higher percentage of outside air. Air should also be fully conditioned for complete temperature and humidity control inside your kitchen and dining spaces.
Buildings that don’t follow codes with improper ventilation can cause health hazards for guests and staff (source).
Make sure you work with an trained professional when selecting the best DOAS unit suitable for the building.
DOAS vs HVAC Unit
The drawback of adding outdoor air to your building is that it may increase humidity indoors.
If the additional moisture is not controlled, it may foster the growth of viruses, mold, mildew, and other potentially dangerous organisms. Controlling the amount of moisture in the building is essential for preventing these byproducts from forming.
A typical HVAC air conditioner is designed with temperature change in mind, and may not be able to handle the additional moisture content
Yes, an HVAC air conditioner does remove some humidity from the air, but the majority of them are only designed to regulate temperature and not to remove moisture effectively. Instead, a system that can fully regulate both temperature and humidity must be put in place.
Restaurant Design With Make-Up Air (MUA) And Rooftop Unit (RTU)
There is typically a RTU that exhausts the air and a MAU that exhausts up to 80% of the air from the kitchen hood. The RTU is required to exhaust and make-up the rest of the air in the kitchen. There are limitations on the capacity of outside air they are capable of handling.
The diagram shows a commercial kitchen such as in a small restaurant or fast food chain.
DOAS for Restaurant Diagram
The diagram below demonstrates how a DOAS unit is capable of combining the role of a RTU and MUA in one unit. The unit also eliminates moisture before entering the kitchen, whereas a typical kitchen attempts to control it after.
Advantages of DOAS for Restaurants
- May eliminate the need for a dedicated make-up air unit and some or all rooftop units
- Saving space on the roof, installation time, and the expense of having multiple units.
- Dedicated units for two different functions
- Full temperature AND humidity control
- Single curb/roof penetration
Common Food Service Applications
- Food halls
- Teaching kitchens
- Open concept kitchens
- Open dining rooms with high occupancy
- Convenience stores
- Event venues
- Ghost kitchen facilities
Hot Water Make-Up Air Unit Heating applications are most frequently utilized in process systems for
Recirculating Untempered Make-Up Air Unit Recirculating Untempered Make-up Air Unit Diagram Table of Contents Overview
Industrial Ventilation Equipment Manufacturers AbsolutAire Learn More FloAire Learn More Canarm Learn More Moffitt Ventilation