Types of Air Conditioner

Different Types of Air Conditioners

Air conditioners come in a number of different formats for use in different domestic and commercial situations.

Here we look at the different designs and where they are best suited to be used including window or unitary air conditioners, split air conditioners, inverter air conditioners, cassette units, free standing units, ducted air conditioners, heat pumps, reverse cycle air conditioners and air conditioner water heaters.

Window or Unitary Air conditioners

The first domestic air conditioners were known as window air conditioners. These consisted of a single box which was mounted in a window or a hole in a wall. The compressor, condensation coil and exhaust fan were mounted in the outer side of the box while the evaporation coil, expansion valve and internal fan were in the inside. These were very noisy units and not very inefficient.

In most parts of the world these have been replaced by split air conditioners although they area still widely available in America.

Split Air conditioners

Split air conditioners have a separate indoor "evaporator" unit and outdoor "compressor unit connected by an insulated hose containing two copper pipes that carry the refrigerant to and from the compressor unit and an electric cable to provide the power to power the fan in the evaporator.

The indoor unit is mounted high on internal walls in a central position in the area it is to cool. The outdoor unit is mounted on brackets an external wall in an open area where heat can be exhausted easily.

Inverter Air Conditioners.

In a standard air conditioner the compressor, which pumps the refrigerant around the system, is driven by an electric motor which runs on standard AC (alternating current) electrical supply which has a serious limitation - the speed cannot be varied, the motor is either on or off. This means that as the temperature in the room varies the air conditioner is constantly switching on and off and this creates surges in the electrical supply every time the motor starts up. This uses more power, noise and wear on the electric motor.

The latest air conditioners have an inverter which converts the AC (alternating current) supply to DC (direct current) supply. The speed of DC motors can be varied and so, with an inverter and a DC motor the compressor can be slowed down or speeded up according to temperature. The air conditioner runs continuously and far more efficiently.

Cassette Units

A Cassette air conditioner is a split system which has a ceiling mounted internal unit and a standard outdoor unit. The ceiling mounted unit has a square grill mounted almost flush with the ceiling with the coil and fan unit hidden above in the ceiling space. Air is drawn in up the centre of the unit and blown out around the four sides of the grill

Cassette units are very useful for cooling rooms and spaces a long way from an outside wall such as corridors and meeting rooms although they often present a challenge for the water drain pipe. The latest versions use a small pump to remove water.

Free standing Units

Free standing units are used in large places such as supermarkets and large stores. They consist of a vertical indoor unit that can be placed in an open floor area, they are connected to a standard outdoor unit.

Ducted air conditioners

Ducted air conditioners are used in commercial environments with a large evaporator unit mounted above the ceiling or in a roof space feeding cooled air through ducting to air vents distributed around the building. The large outdoor units are often mounted on roofs.

Heat pumps

A heat pump operates in the same way as a split air conditioner except that the cooling cycle is reversed. Heat is absorbed from outside a room or building and exhausted inside. A heat pump is generally speaking four times as efficient (uses a quarter of the amount of electricity) for heating when compared with a standard electric heater.

Reverse cycle air conditioner

A reverse cycle air conditioner is a combined air conditioner and heat pump. The cooling cycle can be reversed so it can provide cooling in summer and heating in winter

Air Conditioner Water Heater

An air conditioner water heater works by feeding the condensation pipe through a tank of water before it goes to the condensation coil, the heat given off as the refrigerant is compressed into liquid is used to heat the water.