Of gas through the impeller acting to make the gas pressure and velocity increase, and then through the diffuser allows the gas to slow down the kinetic energy of the gas pressure, gas pressure can be a corresponding increase. With the machinery manufacturing technology, electronic control technology, large-scale air-conditioning systems and petrochemical industry, the continuous development of the centrifugal compressor from the refrigeration heat capacity performance, environmental characteristics, unit volume and solar air conditioning system have been improved significantly and improve, in particular, air conditioning, large cooling capacity of air-conditioning unit has an irreplaceable position, according to incomplete statistics, the cooling area in 5000 ~ 10000m2 buildings in cities, 40% of centrifugal chillers; air-conditioned area of ??10000m2 above the city buildings, 60% of centrifugal chillers.
    However, due to the high speed of a centrifugal compressor, on the strength of materials, machining accuracy and manufacturing quality are demanding, or easily damaged, and the overall efficiency of a small centrifugal compressor is less than a piston compressor, centrifugal compressor for large or special-purpose spaces, central air conditioning system. Nevertheless, the centrifugal chillers in its stand-alone refrigeration capacity, small footprint, low energy consumption, less wearing parts, high reliability, low maintenance, etc., are widely used in high-rise office buildings, hotels, theaters, shopping malls hospitals and other places the comfort of central air-conditioning and petroleum, chemical, metallurgy, chemical fiber, electronics, nuclear power plants and other industrial sectors of the industrial cooling and process. With the growing tension of the world's energy, energy saving is a major trend in product development. In addition, due to the continuous improvement of people's living standards, building energy consumption is increasing, with the highest coefficient of performance of centrifugal chillers will undoubtedly become a hot market.
    3 Conclusion
    In recent years, along with the materials, machining, electrical, and control of industrial and technological progress compressor technology has also been rapid development of the whole of the refrigeration system energy efficiency has been greatly improved. However, due to the dual pressures of the increasingly tight energy supply and environmental protection, prompting us to explore the technological development of the new century, refrigeration and air conditioning industry, to accommodate the development requirements of China's energy-saving first "energy solar power air conditioning and the resources to sustain their use of the environment continues to improve social development goals.