An air conditioning unit is a must-have in any house these days, especially during the summer months. If you are planning to invest in one, then you should have a basic knowledge of the parts and functioning of the appliance to get the most from it. So, when you talk to the service center or are looking up for basic maintenance tips, you will have a clear idea of what you can do.British thermal unit (BTU)The cooling capacity of the air conditioner is measured in BTUs. The technical explanation definition of BTU is the amount of energy required to increase the temperature of one pound of water by one degree Fahrenheit. When you check out AC models, (for example Hyundai HY18S3G 3 Star Split AC (1.5 ton) or Voltas 1 Ton 22DYE Split AC), the product specification will give you the capacity details. It is usually mentioned as tonnage (1 Ton= 12,000 BTU/hour).DuctIt is a pipe used to supply, return or exhaust air. While servicing the air conditioner, you should ensure that the ducts are cleaned and free from any debris or deposits. Any clog in the duct can reduce the performance of your AC.DiffuserOn top of the ductwork, you can see the diffuser. The function of this small part is to distribute air in the required directions using vanes.FansYes,there are fans inside the AC unit. These fans are powered by alternating current (AC) and allow for proper air flow inside the cooling appliance.Condensing unitThis unit of the air conditioner houses the motor, heat exchanger and compressor. It comes as a single unit and usually mounted inside the room with the evaporator set outside the room.CompressorThis AC part compresses the refrigerant to enhance the performance of the air conditioning unit. There are two types of compressors – screw and scroll. The screw type compressor uses a pair of synchronized screws to compress the refrigerant. In the scroll compressor, one fixed and oscillating screw pressurize the refrigerant.RefrigerantIt is the actual substance that helps reduce the temperature of the surrounding area. The type of refrigerant used determines the performance, efficiency and eco-friendly factor of the AC. Some of the commonly used refrigerants are water, air, ammonia, carbon di oxide, fluorocarbon compounds and hydrocarbons.AccumulatorThe liquid refrigerant flows back into the accumulator from the evaporator. The accumulator makes sure that the refrigerant doesn’t reenter the compressor.