Types of Air-conditioning Systems

The following summaries can assist you in identifying the most common types of air-conditioning (AC) systems in apartment buildings.

1. Condenser Water LoopA cooling tower and condenser water pumps remove heat from individual compressors inside apartments. Some of these also heat in winter using a Raypak boiler or heat pump. All plant except the compressor and fan inside the apartment is metered through the common property meter.The key components are:

Indoor unit in the apartment Heat rejection system - cooling towers on the roof of the building Water pipes running to and from the cooling towers and indoor systems Gas boiler or electric heat pump

Cooling Tower(managed by the owners corporation)

Indoor Unit(managed by apartment residents)

2. Chiller / BoilerA large, central compressor provides cold water to a heat exchanger - Fan Coil Unit (FCU) -inside apartments. Fan Coil Units (FCU) in apartments contain a fan that draws air into the unit then blows it over a cooling or heating coil. The air comes out of the FCU either cooler or hotter than before.FCUs will generally have a chilled water coil for cooling and either a hot water coil for heating or an electric heating element. A chiller, located on the roof or in the building’s plant room, provides cold water. The chiller can be air-cooled or water-cooled (i.e. has its own cooling tower).A boiler, generally located in the plant room, provides hot water.All plant, except the FCUs inside apartments, is metered through the common property meter.

Air-cooled chiller Water-cooled chiller

Boilers

Fan Coil Units

3. Multiple condensing units. Chilled refrigerant is provided to each apartment by multiple large, compressors located centrally. Refrigerant pipework is insulated and provides chilled refrigerant to an evaporator within a Fan Coil Unit (FCU) inside the apartment. A key characteristic is the cooling fans located at the top of the equipment.All plant, except the FCU inside the apartment, is metered through the common property meter.

Condensing Units

4. Variable Refrigerant Volume (VRV) or Variable Refrigerant Flow (VRF)

VRVs/VRFs utilise a larger external condenser to provide cooling or heating to many indoor Fan Coil Units (FCU). The system varies the quantity of refrigerant flowing based on the demand for cooling or heating. The units are able to provide simultaneous heating or cooling to different indoor units. Additionally heat recovery units are able to use the heat rejection from a space in cooling mode to heat a space in heating mode. They are common in newer buildings and very efficient. All plant, except the FCU inside the apartment, is metered through the common property meter. The functional description of the system or the nameplate displayed on the units will indicate if the system is VRV.

A VRV System

5. Packaged air conditioning unit Package units house all the components of an air conditioning system in one unit, such as the heatrejection equipment including the compressor and condenser coil, as well as the air supply side of the system delivering conditioned air to the required indoor zones.Typically, they are mounted on the roof and connected to apartments via a duct through which the heated or cooled air is provided. They are generally metered through the apartment meter if present.

Packaged Unit

6. Split SystemsSplit systems consist of a compressor unit that is installed outside (on a balcony or attached to an external wall) and one or more indoor air units. They are usually used to heat & cool one or more rooms, or an open-plan area. They are metered through the apartment meters.

Compressor A variety of styles(outside) of Indoor air units

Typical “Split System” Unit used in individual apartments (External Compressor and internal delivery unit)