Research On The Refrigeration Performance Matching Of Double Machine Double Screw Compressor

Since the economic level has undergone a significant increase, the demand of chiller plants in the production of the relevant domains, such as HVAC, medical industry, has achieved a higher standard. In order to enhance the operational efficient of chiller plants, satisfy the demands domestically and internationally, and reduce the energy consumption, more effort should be made to deeply analyze and investigate the chiller plants, which could facilitate the manufacturers to produce more effective chiller plants with proprietary intellectual property rights. However, the chiller plants with double machine double screw compressor have the characteristics of high coefficient of performance and cooling capacity. At the same time, the occupied areas are relatively smaller when compared to other chiller plants. Besides, it is of significant simplicity to operate and maintain the chiller plants. Specifically, this type of chiller plant mainly serves the range from-30 Centigrade to-60 Centigrade.In this thesis, the operational process of the chiller plants with double machine double screw compressor is analyzed. Based on this, a steady mathematic model is developed. According to the advantages and disadvantages of the three types of refrigerants (including R22, R134a and R410a) and the thermal properties of the refrigerants, simulations have been conducted to investigate the influence the changes of medium temperature have upon the coefficient of performance when utilizing those refrigerants in various conditions (e.g., standard condition, low-temperature condition and air-conditioning condition). In terms of the simulation results, the medium temperatures of those refrigerants in different conditions are obtained, which means the optimal medium pressure of the system has been received. At the same time, when utilizing the various refrigerants, the influence of the changes of evaporative temperature and condensing temperature upon the COP, cooling capacity, energy consumption and medium pressure is analyzed and compared, which can facilitate to search for a more suitable refrigerant. Finally, simple analysis has been conducted to compare the chiller plants with double machine double screw compressor to the screw chiller plants with economizer. Based on the analysis, the shortages and advantages are found to optimize the chiller plants with double machine double screw compressor, which could achieve the energy saving potential.Based on the research and comparison of simulation results, the chiller plants with double machine double screw compressor could effectively lower the rejected temperature. Even under the low evaporative temperature, the system can also have a higher COP and cooling capacity. At the same time, the COP of system can achieve the highest level when under the optimal medium pressure.