Thermal · 23/04/2020 0

Window Air Conditioner | Air-Conditioning System


This is also called as window type room air-conditioner because it can be accommodated in window of walls. Window Air Conditioner unit is suitable for cooling the rooms in hot summer. The window air-conditioner works on the vapour compression refrigeration cycle.

A window air conditioner is the most basic kind of air conditioning system, and it is positioned on the outside of windows or the inside of walls. It is a single unit that has been constructed in a case that contains all of the components.

This refrigeration unit is equipped with a twin shaft fan motor, which has fans positioned on each side of the shaft. One is located on the evaporator side, while the other is located on the condenser side.

Description of Window Air Conditioner


The basic components of a window air conditioner are compressor, condenser, a capillary tube and an evaporator, in addition filters, accumulators, motors, fans and electrical controls. This unit consists of

1. A cooling system to cool and dehumidify the air which includes a condenser, a compressor and a refrigerant coil.

2. A filter to remove any impurities in the air. The filter is finished of with mesh, glass wool or fibre.

3. A fan and adjustable grills to circulate the air.

4. Controls to regulate equipment operation.

Working Principle of Window Air Conditioner

The high-pressure refrigerant which comes out of the compressor is condensed in the condenser using ambient air a coolant. The liquid refrigerant is expanded in a capillary tube and then enters the evaporator. Here, it evaporates and roots the refrigeration effect. Then fan blows the fresh air over the evaporator coil, which cools the air. The cool air is supplied to the room. Meanwhile, refrigerant from the evaporator enters the compressor to be compressed and the cycle repeats itself. The return air from the room is exhausted by the evaporator fan be blowing air over the condenser coil, where it picks up heat from the refrigerant.


Panel on the front of the Window Air conditioner

The front panel in window air conditioner is the one that is visible to the user from inside the room where it is located, and it is equipped with a user interfaced control, which may be either electronic or mechanical in operation. Older window air conditioners are often of the mechanical control kind, with rotary knobs for controlling the temperature and fan speed of the air conditioner.

More recent units are equipped with an electronic control system, which allows the user to operate the functions via the use of a remote control and a touch panel with a digital display.

The front panel is equipped with horizontal and vertical (on certain versions) louvres that may be adjusted to guide air flow in the direction that is most comfortable for the user.

An intake of fresh air from the outside, denoted by the symbol VENT (ventilation), is offered at the panel in the case that the user desires a specified quantity of fresh air from the outside.

When comparing the mechanical type to the electronic kind, the mechanical type is generally less expensive. If all you want is to chill the space and aren’t concerned with aesthetics or extra functions, a mechanical air conditioner will suffice.

Components on the indoor Unit in Window Air Conditioner

The following are the indoor components of a window air conditioner:

1. Cooling Coil:

A cooling coil with a built-in air filter is the primary component in window air conditioner. This coil is where heat exchange occurs between the refrigerant in the system and air in the room. It is also known as the condenser.

2. Fan Blower:

Using a centrifugal evaporator blower to discharge cold air into a room, the fan blower may be used to chill a space.

3. Capillary tube:

A Capillary Tube is a device that allows for expansion. If it is situated too close to the evaporator, it might make a lot of noise during operation.

4. Operation Panel:

The temperature and speed of the blower fan are controlled via the usage of the Operation Panel. A thermostat is used to gauge the temperature of the return air, and another thermostat is used to monitor the temperature of the coil. Mechanical or electrical controls may be used to govern a system.

5. Filter Drier:

Filter Driers are used to eliminate moisture from the refrigerant during the cooling process. It is necessary to employ a Drain Pan to collect the water that condenses on the cooling coil and is then released to the outside by gravity.

Components on the outdoor Unit

The outdoor components are as follows:

1. Compressor:

The refrigerant is compressed with the use of a compressor.

2. Refrigerant Coil:

The condenser coil is responsible for transferring heat from the refrigeration system to the outside air. In an air-cooled condenser, a propeller fan is employed to assist in the movement of air molecules over the surface of the condensing coil.

3. Blower Fan:

This is where the fan motor is placed. This fan features a twin shaft, which allows it to link both the inside blower and the outside propeller fan in one unit.

Operation of Window Air Conditioner

The compressor used in a window air-conditioner is hermetic type, which is sealed in a casing with a motor. The condenser coil is a continuous copper coil with aluminium fins. The capillary tube is 40 cm long, usually with 0.75 mm diameter. Evaporator coil is also made of copper with aluminium fins. Dampers and louvers are provided for intake and exhaust on both sides of the air-conditioner casing.

A one ton window air-conditioner circulated 4 m³/min of air in the room. Some fraction of air is fresh, whereas some fraction of air is recirculated. Filters are used to filter air entering the air-conditioning unit. The filter is plastic foam or metallic mat type. The controls used by the unit are

a) Thermostat Control: This is used to set the room air temperature. Usually it is a bimetallic strip.

b) Master Control: It is an electrical switch used to stop or start the compressor motor.

The installation of the unit is done either in the wall or by using external brackets or locating it inside the room with exhaust flush to the window. In either case, the condenser should be facing outside and the evaporator should be facing inside. It is advisable to install the unit for a minimum sun exposure as sun’s rays can diminish the efficiency of the condenser. The air louver inlets should not be blocked and provision for draining of the condensate must be provided. Maintenance of the window air-conditioner should include interrupted cleaning, replacing filters and air seals and lubrication of fans.