ABSTRACT
254Refrigeration is the most important utility required for dairy plants for low temperature storage of different food and dairy products. It is also very essential for cold chain of handling of milk and other perishable food products. Vapor compression refrigeration system using ammonia as refrigerant is widely used in India for industrial refrigeration, air conditioning, and cold storages. In dairy processing plants, ice-bank system of refrigeration is used for chilling and processing of milk, while direct expansion air chillers are employed for cold storages. Multicompression and evaporators systems are being used for the storage of icecream and many other frozen products. The refrigeration system uses electrical energy for operation of compressor and other auxiliary components of the system. Performance evaluation and efficient operational management of refrigeration plants are very important as electrical power consumption of refrigeration plant alone is about 50-60% of total electrical consumption of the dairy and food plants, depending on the nature of processing operations. Vapor absorption refrigeration system can be used in dairy plants using waste thermal energy or using cogeneration system.
This chapter covers the working of vapor compression system, factors affecting performance of the refrigeration system, system components including ice-bank and ice silo, controls, maintenance, etc. The use of refrigerant properties, tables, and charts for thermodynamic analysis of vapor compression refrigeration system is also described. The calculations for estimating refrigeration plant capacity for bulk milk cooler, chilling center, cold storage, and dairy plant are also presented. The most commonly used refrigerants for vapor compression refrigeration systems and safety aspects of ammonia as refrigerant are also presented.
