Refrigeration compressor energy-saving development

In recent years, in addition to the continuous improvement of its own performance, the research and development of the compressor, which is the core component of the refrigeration system, has been centered on the two major themes of environmental protection and energy saving. The main technical developments include the following aspects.

Frequency conversion technology and digital vortex

The compressor’s stepless and continuous capacity adjustment can better match the load changes of the refrigeration unit and effectively improve the unit’s operating efficiency and adaptability in all working conditions. Variable frequency rolling piston and rotary cavity compressors have been widely used in various types of air conditioning units. Currently, variable frequency technology is being expanded to piston, screw and even centrifugal compressors, and the output of variable frequency piston compressors for refrigerators is also gradually expanding. my country’s new air-conditioning energy efficiency standards promulgated in September 2008 will further stimulate the development of frequency conversion technology. The application proportion of digital scroll compressors with mechanically continuously variable capacity in multi-unit air conditioning units is gradually expanding.

Adapt to changes in refrigerant

CFCs and HCFCs refrigerants, which have a destructive effect on the ozone layer, are phased out substances stipulated in the Montreal Protocol. They began to be gradually replaced by HFCs and natural working fluids in the late 1980s. Compressors have made major technical improvements to adapt to alternative refrigerants, and HFCs refrigerant compressors such as R134a, R404A, R407C and R410A, as well as HCs refrigerant compressors such as R600a and R290, have been developed. CO2 transcritical cycle compressors have been successfully used in automobile air conditioners and heat pump water heaters. Ordinary CO2 compressors and NH3 cascade systems are being used in commercial refrigeration, and closed NH3 compressors are being used in air conditioners and refrigerators.

Economizer air supply and single-machine multi-stage compression

The normal working temperature difference between condensation and evaporation of a single-stage compression refrigeration system is 40-60°C. In applications such as cryogenic and low-temperature air source heat pumps, this temperature difference can reach 75°C. In order to enable a single compressor to produce a large temperature difference, economizer air supplement (EVI) screw compressors and scroll compressors have been mass-produced, and air supplement piston compressors and rolling piston compressors have also been studied. Multi-cylinder piston compressors with single-machine two-stage compression are increasingly used in refrigeration equipment. Double-cylinder rolling piston compressors with single-machine two-stage compression have been successfully developed and started to be used. The single-machine three-stage compression centrifugal compressor is already a symbol of high energy efficiency.

Compressors for special and specialized purposes

The shaft seal is the core component of the bus air-conditioning compressor, which is still the leading domestic brand. Rolling piston compressors dedicated to air source heat pump water heaters have been mass-produced. Compressors for air conditioners and refrigerators driven by various special power sources such as 12V, 24V and 48V DC have also been mass-produced, and are mainly rolling piston, piston and triangular rotor types. Microcompressors for microelectronic device cooling and human body air conditioning are also under development.

In short, compressor technology must adapt to changes in the times, constantly improve its performance, continue to expand its application areas, and continue to develop new compressors.

Expand capacity range and application areas

The longest and most adaptable reciprocating piston compressor is a general-purpose model with a wide capacity range. It continues to dominate the refrigerator and commercial refrigeration fields, but is dominated by rolling piston, scroll and screw compressors in the air conditioning field. challenges.

Compact centrifugal compressors with magnetic bearings are highly mechatronic products that are beginning to be used in chillers and begin to overlap with screw compressors in capacity. Large scroll compressors and fully enclosed screw compressors have been mass-produced, and the two have been connected in terms of capacity. The output of scroll compressors used for refrigeration continues to grow, and three-screw compressors have also been put on the market. Rolling piston compressor capacity range has been extended up to 14hp, down to 1/8hp. In order to solve the leakage and wear problems after using R410A, research on the deformation structure of rolling piston compressors is extremely active, among which the swing rotor compressor has been applied in engineering.