Selection of 3X400 Ton Centrifugal Water Chillers for Central AIC Plant --- A Case Study

The selection of a centrifugal system for chilling water and its optimum location have been carried out in the present case study based on (a) energy conservation, (b) economy and (c) operation and maintenance. The, comparison is done between the R-11 open and R-12 hermetic centrifugal water chillers (eWes). Thermodynamic analysis for 400 ton renders the capacity of the former to be 8 ton higher than that of the latter. The former is also found to be better than the latter for air-conditioning and inferior to the latter for heat pump use. Moreover, for the year round air-conditioning the hermetic unit stands a better position. The evaluation of various quantities based on the location of the central ewes shows an additional expenditure of Rs. 1. 4 million for the plant of Rs. 13.6 million due to (a) 79 kW of loss of refrigeration· by heat transfer, (b) 16 kW of refrigeration loss due to more pumping energy, (c) 16 kW of increased pumping power and increased cost of larger size pumps and (d) losses of power and more maintenance cost. Further, the use of ozone friendly and proven refrigerants like R-717 and R-718 is stressed.