Packaged Rooftop Unit Systems (RTUs)
RTU’s, or package rooftop units, are usually capable of performing heating, cooling, air filtration and have economizer’s for ventilation air, and free cooling when outdoor temperatures are below a certain point. All the components are contained in one package. These units can also be installed at ground level and ducted into a building.
Commercial Split System Cooling Units
What is commonly called a split system is a cooling system with components located in different places. Typically, the outdoor unit is referred to as a condensing unit and contains the system compressor and the condenser coil which reject the heat to outdoors. The indoor section usually referred to as the air handler contains the evaporator coil and the refrigerant metering device and this is the part of the system which absorbs heat from the indoor air.
Commercial Heating Boilers
Heating boilers are more common in commercial buildings than residential buildings. Water boilers do not actually boil water. Steam boilers do boiler water and operate differently from water boilers.
Water boilers have circulators (pumps) that circulate the water being heated through the boiler and the system. Water boilers have other equipment to maintain proper system water pressure and controls to maintain the proper temperature.
Steam boilers do boil water into steam and are controlled with pressure controls that limit the pressure that is produced by the water expanding into steam. Steam boilers use water level controls to maintain the proper water level in the boiler. Steam boilers do not use circulators. The pressure of the steam in the boiler causes the steam to be distributed to the system.
Commercial Air Handlers
Air Handlers distribute air to conditioned spaces and have filter banks that clean particles from the air. They can also have UV lamps or Plasma units to purify the air and humidifiers to raise the humidity. Heating the air is accomplished with hot water, steam or electric coils. Cooling is accomplished with chilled water or refrigerant coils.
Commercial Ductless Systems
Ductless systems are usually heat pumps that heat and cool. These split systems use indoor consoles/air handlers that do not use ductwork and only condition the space they are located in. These systems come in multi indoor unit configurations and all units can cool a space or heat a space, however, they can only perform one function at a time.
Variable Refrigerant Volume (VRV) Systems
Variable Refrigerant Volume (VRV) systems, referred to by most manufacturers as Variable Refrigerant Flow (VRF) systems are like ductless systems but really are an alternative to more expensive hot water and chilled water systems. VRV systems do have indoor air handlers that are able to be ducted.
See our HVAC Terms for more details