COP-restricting Parameter Analysis of Centrifugal Refrigerating Units

摘要

The method of variance analysis was used to analyze the effects of four parameters,i.e.the opening degree of guide vane,the proportion of actual operating load,the outlet temperature of cold water,and the outdoor wet-bulb temperature,on the coefficient of performance (COP)of centrifugal refrigerating units.When the confidence level is set as 95% and 99%respectively,the results of single-factor variance analysis of the above four parameters show that the test statistic F of the opening degree of guide vane is higher than its critical value F0.01 (r-1,n-r) ,and the F of the proportion of actual operating load and the outlet temperature of cold water are higher than their own critical value F005 (r-1,n-r) ,which proves that their impacts on the COP are significant,while the impact of outdoor wet-bulb temperature is not significant.The results of two-factor variance analysis of the outlet temperature of cold water and outdoor wet-bulb temperature show that their interaction has remarkable impacts on the COP.The actual COP value of centrifugal refrigerating units can increase by 6.885%averagely under the condition of the invariable refrigerating capacity after adjustment according to the analytical results.