The air conditioner can be considered as the heart of the cooling system. Compressors are composed of working parts by moving mechanically in terms of their internal structure, which causes the most failures. In the refrigeration cycle, it absorbs the low pressure refrigerant with its mechanical structure and is the main element of the refrigeration system, which performs the task of compression at high pressure.

Today, three different types of compressors are generally used in household air conditioners. Of course, the work they do in the refrigeration cycle logic is the same. What separates them from each other is the mechanical structure used for suction and compression. They are named after this mechanical structure used in compressors. For example, the internal structure of the compressor, which we call reciprocating type compressor, has mechanical parts such as piston, cylinder and crank for suction and compression. It is possible to classify the most commonly used compressor types in household air conditioners as shown in Figure 2.1 below, in terms of their general structures.
The following features are sought in compressors used in air conditioning systems.
– Having as little torque as possible at first starts
– Maintaining safety and security in different working conditions
– Vibration and noise levels do not exceed a certain level at partial and full loads and under different conditions.
– A continuous capacity control and wide load variation, adaptability to the operating regime
– Providing unit cooling value by consuming less power
– Efficiency does not decrease at partial loads
– Having a safety device in case of refrigerant liquid impacts, high pressure and temperature operation
– Cost as low as possible

However, it can be said that there is no compressor that has all these characteristics. The compressor, which can provide the most of the above characteristics according to the conditions in the applications, is preferred in the selection.