A complete air conditioning system needs a main engine with several terminal systems (fan coils), which can achieve the effects of cooling in summer and heating in winter. The most important part of the air conditioner host is the compressor, which completes the process of gas compression and transportation by changing the volume of gas, and needs this power to complete it. Then, let’s take a look at five common types of refrigeration compressors, so as to better understand the host system and reserve more knowledge for selecting the host in the future.
1. Semi-sealed piston refrigeration compressor
Among all type of refrigeration compressors, piston compressor is that first one which come out and has been widely used up to now. For example, semi-closed piston refrigeration compressor is widely used in refrigeration equipment.
Semi-enclosed piston refrigeration compressor features: wide range of energy pressure and refrigerating capacity, low material requirements, mature technology, simple compressor system, but afraid of liquid impact.
There are two common faults in semi-closed piston refrigeration compressor: mechanical fault and electrical fault. The common mechanical faults are wear or damage of connecting rod, crankshaft and valve plate; The electrical faults are short circuit, open circuit and burning of motor winding.
2. Double-rotor refrigeration compressor
Double-rotor compressors are widely used in household appliances nowadays, and the export scale of rotor compressors is increasing year by year, with a compound growth rate of 12.8% in the cold year from 2009 to 2019. Now, many air-conditioning equipment choose double-rotor compressors with less than 7 horses.
Rotor compressor features: few parts and simple structure. Less vulnerable parts, reliable operation. There is no suction valve, so the clearance volume is small, the gas transmission coefficient is high, the machining accuracy is high, the sealing performance is poor, and the leakage loss is large.
What are the advantages of scroll compressor and double-rotor compressor?
The advantages of dual-rotor compressor are: low frequency energy efficiency ratio is good, high frequency energy efficiency ratio is inferior to scroll, noise vibration wear is slightly larger than scroll, service life is shorter than scroll, and it is difficult to make large displacement.
Scroll compressor has the advantages of average low-frequency energy efficiency ratio, better high-frequency energy efficiency ratio than scroll, less wear due to noise and vibration, long service life and large displacement.
3. Scroll refrigeration compressor
Scroll compressor is mainly composed of moving disk (scroll rotor), stationary disk (scroll stator), bracket, cross coupling ring, back pressure chamber and eccentric shaft. It can be divided into two types: low pressure chamber compression and high pressure chamber.
The compressor with low pressure cavity is characterized by low temperature in the whole shell and low pressure in the shell cavity (except the exhaust port and exhaust cavity); The compressor with high pressure cavity shows that the whole shell is high temperature, and the inside of the shell cavity (except the suction inlet and suction cavity) is high pressure.
Scroll compressor features: stable operation, low vibration, quiet working environment, few wearing parts, stable operation, low noise, long service life and high EER value, which are used in refrigeration and air conditioning systems.
4. Screw refrigeration compressor
Screw refrigeration compressor is mainly composed of casing, rotor, bearing, shaft seal, balance piston and energy regulating device. In screw refrigeration compressor, two screws with spiral tooth grooves are engaged and rotated, resulting in the change of the volume between teeth, thus completing the process of suction and compressor, and the cooling capacity can be infinitely adjusted between 10% and 100%. Screw refrigeration compressors are now widely used in refrigeration and HVAC equipment.
Characteristics of screw refrigeration compressor: high strength and wear resistance of rotor and bearing; The exhaust volume is hardly affected by the exhaust pressure. Maintain high efficiency in a wide range of working conditions; Energy stepless regulation can be realized, and it is insensitive to liquid inlet.
5. Centrifugal refrigeration compressor
Centrifugal refrigeration compressor belongs to speed compressor, which is a kind of impeller rotating machinery. It works on the gas by the impeller rotating at high speed to increase the pressure of the gas. Almost all refrigeration compressors with single capacity above 1200kW are centrifugal compressors, which are generally used in large and super-large air-conditioning equipment.
Characteristics of centrifugal refrigeration compression: good dynamic balance characteristics and small vibration; Less wear parts, long continuous operation period; It is easy to realize multi-stage compression and throttling, and realize multiple evaporation temperatures; Stepless adjustment can be carried out economically; When the refrigerating capacity is small, the efficiency is low; Easy to surge.
