REFRIGERATION

As an Engineman, you must have a knowledge of refrigeration and air-conditioning systems. Much of the information pertaining to refrigera-tion will also apply to various air-conditioning systems that will be discussed in chapter 17. When you are assigned to a ship, you will learn how to start, operate, stand watch on, and secure these systems. You may also be assigned to assist with the maintenance of refrigeration plants. Before you can do these things, however, you must have a thorough understanding of the operating principles of these systems. You can learn these principles if you study this chapter thoroughly and carefully.

Most refrigeration systems used by the Navy use R-12 as a refrigerant. Chemically, R-12 is dichlorodifluoromethane (CC12 F2 ) one of a family of halocarbons. At atmospheric pressure, the boiling point of R-12 is - 21.6F, which is more than 50 lower than the freezing point of water. The boiling point of R-12 may be lowered even more by operating the low pressure side of a refrigeration system at less than atmospheric pressure (partial vacuum). You should realize, however, that the cycle of operation and the main components of R-12 systems are basically the same as those in reciprocating refrigeration and air-conditioning plants that use other kinds of refrigerant.

After studying the information in this chapter, you should be able to understand the fundamen-tal concepts of refrigeration. You should also be able to identify the major components of a refrigeration system in terms of their functions, relative locations, associated components, and purposes within the system.