Rooftop Package Unit is a very common commercial and industrial heating, ventilation and air conditioning (HVAC) system. As the name suggests, its main feature is that the entire set of equipment is installed on the roof of the building.
Its core function is to provide an integrated and one-stop air treatment and temperature control solution for the entire floor or large open space.
1.Core Function：
Rooftop package units are "all-rounders", usually integrating all or most of the following functions
Cooling
Through the internal compressor, condenser and evaporator coil, it circulates the refrigerant like a large air conditioner to cool the air.
Heating
Heating by Gas (The Most Commom): Built-in gas stove heats air by burning natural gas or propane.
Electrical Heating: Heat the air through resistance-type electric heating coils.
Heat Pump: Some Rooftop Package Units can operate in reverse, absorbing heat from the outdoor air for indoor heating, which is more energy-efficient.
Ventilation
Fresh air is drawn in from outside and mixed with the indoor return air to ensure indoor air quality (IAQ) and oxygen content. Expel the stale air inside the room.
Air Handling
The regulated air is forcibly delivered to various areas inside the building through the Ductwork by large fans. Contains filter for filtering the pollutants such as dust, pollen in the air.
In simple terms, it draws air back from the interior of the building, undergoes a series of treatments such as cooling/heating, filtration, and mixing with fresh air, and then sends the treated air back into the building through the duct system.
2.Main Features and Advantages
Saving indoor space: This is the most prominent advantage. All heavy equipment (compressors, fans, heat exchangers, etc.) is installed on the roof, not occupying the valuable commercial or office space inside the building. Easy installation and maintenance: all components are concentrated in an enclosure, install as will the entire unit lifting to the roof and connecting duct and piping. Maintenance personnel can also carry out most of their work on the roof without disturbing the daily activities inside the building.
Integrated design: Users do not need to purchase air conditioners, furnaces, and ventilation systems separately. One RTU can meet all their needs. Apply to low-rise buildings, very suitable for large open space, such as：
Supermarket, Shopping Mall
Warehouse, Manufacturing Plant
School, Gymnasium
Restaurant, Cinema
Low-rise Office Building
3.Working Principle
Return air: The warm air inside the room is drawn into the roof unit through the return air duct.
Mixing Air: The return air is mixed in proportion with the fresh outdoor air drawn in through the blinds.
Filtration: Mixed air passes through an air filter to remove particulate matter.
Adjust the Temperature:
Summer: Mixed air flows through the cold evaporator coils, being cooled and dehumidified.
Winter: Mixed air flows through the burning gas heat exchanger or electric heating coil and is heated.
Air Supply: Large fans force the regulated air to be delivered to various areas within the building through the air supply ducts.
Heat Removel/Heat Absorption
Summer: The refrigerant transfers heat to the condenser coil, and the hot air is discharged outdoors by the fan.
Winter (Heat Pump Mode)：It operates in reverse to absorb heat from the outdoor air and bring it into the room.
4.Compare with Other AC Systems
|
Features |
Rooftop Package Unit |
Split AC System |
Chilled Water System |
|
Installation Position |
On the Rooftop |
Indoor and Outdoor |
The large mainframe is located in the computer room or on the roof, and there are fan coil units indoors |
|
Fit for Buildings |
Low-rise, Large-space Commercial Buildings |
Residence, Shop, Single Room |
High-rise office buildings and large commercial complexes |
|
complexity |
Medium, Integrated |
Low |
High, Complicated Systems |
Summary
Rooftop package unit is a large-scale integrated HVAC equipment designed for commercial and industrial buildings, integrating cooling, heating and ventilation functions. It saves indoor space by being installed on the roof and provides treated air to the entire floor through a duct system. It is commonly found in places such as supermarkets, warehouses and low-rise office buildings.
