Types of Air Conditioning Systems

2023-08-31 14:19
Window unit air conditioner

In a window air conditioner, all the components, namely the compressor, condenser, expansion valve or coil, evaporator, and cooling coil are enclosed in a single box package. This unit is fitted in, commonly, a windowsill, eliminating the need for ducting.


The split air conditioner is comprised of two parts -- the outdoor unit and the indoor unit -- and comes in single split or multi split configurations.

Single Split System

In a single split air conditioner, one outdoor unit runs the system to provide conditioned air from an indoor unit.

Multi Split System

The outdoor unit of a multi split air conditioner runs more than one indoor unit. A popular choice for owners of newly built houses. Because it requires only one unit outdoor, a multi split system contributes to a sleek house appearance.

Requirements for Multi Split System Installation

The following requirements should be taken into consideration.

Piping Routes
A multi split system needs piping to connect the outdoor unit and multiple indoor units. Dimensional constraints should be reviewed beforehand to ensure the installation of all piping.

Outdoor Unit Capacity
The total capacity of the indoor units has to be kept below the capacity of the outdoor unit.

Air-to-Water (AtoW) Heat Pump

An AtoW heat pump traps heat from the air to warm the refrigerant. Like a split system air conditioner, the AtoW system is comprised of an indoor unit and outdoor unit. Heated water is stored in a tank inside the indoor unit and used for showering, drinking, interior air heating or floor heating.
The technology uses heat in the air and has been drawing attention in Europe, where environmental concerns are prompting people to move from conventional combustion boilers to systems that are less impactful on the environment.
Aquarea J Generation is a feature-packed air-to-water heat pump system mainly for Europe market representing Panasonic's latest technologies.

Types of Air Conditioning Systems -Commercial Air Conditioning

Cooling/heating capacity is where commercial/industry air conditioning systems significantly differ from residential air conditioners. Commercial/industry air conditioning systems are roughly classified, by their capacity, into those for medium-size offices or stores and those for buildings and large facilities.
Indoor units come in a variety of types to meet varying requirements that are defined by space volume and applications.

Office/Store Air Conditioning Systems

Single-Split Packaged Air Conditioners
In a single split air conditioner, one outdoor unit runs the system that provides conditioned air from an indoor unit.

Multi-Split Packaged Air Conditioners
In a multi split air conditioner, one outdoor unit runs more than one indoor unit, making it a popular choice for owners of stores and stand-alone offices.

Packaged Terminal Air Conditioners
A packaged terminal air conditioner (PTAC) is a ductless, self-contained through-the-wall heating and cooling system commonly found in hotels, housing facilities, and apartment buildings. With indoor evaporation units and outdoor condensation units connected through walls, PTACs are installable in a smaller area and provide individual air conditioning.

Building/Factory Air Conditioning System

In a variable refrigerant flow (VRF) system, one outdoor unit runs more than one indoor unit. VRFs are typically installed in medium to large buildings bigger than stores or stand-alone offices for which multi-split packaged air conditioners are the popular choice. Being operated at varying speeds, VRF units adjust to the needed rate allowing for substantial energy savings. Those that come with compact outdoor units designed for small to mid-size buildings are called mini VRFs.

Gas Heat Pump (GHP) Air Conditioning System
A gas heat pump (GHP) air conditioning system has a gas engine-powered compressor inside the outdoor unit and a heat pump to heat or cool air in living spaces.

A chiller is a machine that removes heat from a liquid via a vapor-compression or absorption refrigeration cycle. This liquid called refrigerant is circulated through a heat exchanger to cool equipment. Chillers are in use for industrial machines and laboratory instruments, to continually maintain optimum temperatures. Commercial buildings and factories also use chillers for air conditioning.

Air Handling Unit (AHU)
An air handling unit (AHU) is a device used to regulate and circulate air as part of a heating, ventilating, and air-conditioning system. It uses cold/hot water or steam to regulate the temperatures and humidity of the air that flows into living spaces.

Central Air Conditioning
In a central air conditioning system, a heat source device installed in the building heats the water circulating in the system. The water flows to and from an AHU to provide conditioned air. That is in contrast to individual air conditioning systems that have heat sources for each floor and area.

Types of Indoor Units

Indoor units of commercial/industrial air conditioners come in various types, depending on room geometries and applications.


Indoor units of a ducted air conditioner are installed in the ceiling space. The air inlet or outlet grilles are the only parts visible on the ceiling surface.


The indoor unit is wall-mounted and entirely exposed.

Ceiling Cassette

The indoor unit of a built-in cassette air conditioner is installed in the ceiling space. The ceiling panel is the only part exposed and visible on the ceiling surface. The unit and ducts, being in the ceiling, are less visible and out of the way.


The indoor unit is mounted on the ceiling surface and exposed.


Being placed on the floor reduces time required for installation.

Additional Equipment for Air Conditioning

Below are apparatuses that help air conditioners provide better room air

Air Purifier

An air purifier or air cleaner is a device which removes contaminants, e.g., dust, pollens, house dust, from the air in a room to improve the quality of indoor air.

Ventilation Fan

An air conditioner provides cool/hot airflow but does not ventilate. Using fan ventilation, together with an air conditioner, ensures fresh air intake all the time.


Using a fan together with air conditioning boosts the cooling effect without unnecessarily lowering temperature. Fans are also useful to effectively deliver cool air to stuffy spaces.


It takes time to warm the entire room with an air conditioner in wintertime. Fan heaters increase the heating efficiency of air conditioning in use.