Control System of the Window Air Conditioners
In front of the window air conditioner there is control panel or the operating panel that carries various control buttons. This control panel can be easily accessed from the front panel of the window air conditioner. The three important parameters that are to be controlled inside the window air conditioner are the room air temperature, the flow rate of the air and the direction of the air. All these controls are discussed below and also shown in figure 1.
1) Thermostat for controlling the room air temperature: For controlling the temperature inside the room there is thermostat. The thermostat sensor is connected directly to the cooling coil to sense its temperature. The thermostat is also connected to the switch in control panel and it has the knob for setting the temperature. The person inside the room can easily set the temperature required by rotating this knob. In the modern window air conditioners, there is printed circuit board (PCB) to which the thermostat is connected. This PCB has remote sensor so the setting of the thermostat can be easily changed by the remote control.
2) Air flow rate inside the room: The motor connected to the blower is of multispeed type, so one can change the speed of the motor. As the speed of the motor changes the amount of air sucked by it and blown by it also changes and so the amount of air delivered in the room also changes. The speed of the motor can be changed by the knob provided in the control panel or by the remote control if the air conditioner has PCB fitted into it.
3) Direction of the air flow inside the room: In front panel of the window air conditioner there are horizontal lovers. Additionally, in front of the air conditioner body and attached to it are the vertical louvers. The chilled air from blown by the blower passes into the room through these louvers. The horizontal louvers in the front panel enable changing the vertical motion direction of the air inside the room. The position of these lovers can be changed manually.
The vertical louvers enable changing the horizontal motion of the air inside the room. These louvers are connected to the small motor. The vertical louvers can be kept moving in the vertical direction so that the air flows throughout the room uniformly or they can be kept in the fixed direction so that the air flows in particular desired direction only. The operation of the motor of the vertical lovers can be controlled by the small button on the control panel of the window air conditioner (refer the figure below especially figure 5 & 6). In case of the automatic window air conditioner with PCB, the motion of the vertical lovers can be controlled by the remote. The horizontal louvers in the front panel and the vertical louvers enable fine control of the distribution of air inside the room.
Parts of Window AC
Front Panel of the Window Air Conditioner
The very front covering of the window air conditioner assembly that is visible to the person is the front panel (many times called as the front grill). For novice people the front panel itself is the whole air conditioner. These days lots of importance is being given to the aesthetics of the front panel so the window air conditioner also serves as the decorative item inside the room. The front panel has two important compartments: return air and supply air compartments. These are described below (please refer the figure above, especially figure 5 & 6).
1) Return air compartment: The return air compartment of the front panel comprises of the return air grill and the air filter. When the blower sucks the air, it is first over the return air grill and then over the air filter. Since the return air from the room comes inside the air conditioner via this part of the front panel, it is called as return air compartment of the grill.
2) Supply air compartment: The supply air compartment of the front panel comprises of the horizontal louvers as described above. The horizontal louvers help changing the vertical direction of air inside the room and their position can be changed manually as per the requirement.
There is another opening in the front panel that provides access to the control panel of the window air conditioner. The front panel of the window air conditioner can be removed easily for carrying out the maintenance works. If you want to remove the filter from the front panel, one can easily slide it out from the side without removing the whole panel.
Drainage System of the Window Air Conditioner
When the room air is chilled by the cooling coil the dew from the air is accumulated on the coil. This dew drops in the bottom base of the window air conditioner and it has to be removed by some system else the water will leak inside the room. For collecting the dew, the window air conditioned is installed with slightly tilted angle toward outside due to which all the dew water gets collected towards the back. There is small opening at the end for the drainage of this water. This opening can be left open or it can be connected to the small drain pan and the piping so that the water is drained out easily.
Electrical Protection System
The hermetically sealed compressor has motor fitted inside it. The compressor is the most important part of the air conditioning system so the motor connected to it should be protected against getting overheated and burning. Due to running of the air conditioner for long time, sometimes the winding gets overheated. To prevent the burning of the coil there is thermostat that senses the temperature of the coil. When the coil temperature reaches certain level, it trips the compressor and stops it until it gets cooled and restarts only after certain lower limit of the temperature is attained.
The air filter is very important part of the window air conditioner. It performs one of the most important functions of the window air conditioner, which is cleaning of the air. The air cleaner is fitted in the front of the air conditioner in the front panel. The room air first passes over the air filter and then over the cooling coil. Thus the filtered and chilled air is passed to the room. For proper working of the window air conditioner system cleaning the air filter once every two weeks is very important. If this is not done dust will get accumulated in the filter and the air will not be absorbed and supplied by the AC. Due to dirt the temperature of the evaporator may become too low resulting in the formation of ice and ultimately complete blockage of the cooling coil.
1) Book: Basic Refrigeration and Air Condtioning by P N Ananthanarayanan, Tata McGraw-Hill Pubishing Company Limited.
5) Book: Basic Refrigeration and Air Condtioning by P N Ananthanarayanan, Tata McGraw-Hill Pubishing Company Limited, Second Edition, page no. 213