William V. Richards

Refrigerant Consultant
Lincolnshire, Illinois

The broad term refrigeration refers to a general science concerned with the use of producing temperatures below normal for commercial or other useful purposes. Refrigeration piping is used in conjunction with refrigeration equipment. Refrigerants are fluids which absorb heat by evaporating at a lower temperature and pressure and transfer heat out when they condense at a higher pressure and temperature. The increase in pressure necessary to elevate the temperature level is produced by a compressor of the reciprocating, rotary, or centrifugal type. In the case of an absorption system, the transfer of heat, thereby boiling the more volatile refrigerant out of a solution.

Fluids which do not change state are sometimes used to transfer heat in an indirect system. Such fluids are called secondary coolants. To be classified as a secondary coolant, the fluid must be used for the transfer of heat without a change in its state. Brine, a solution of salt and water, is a secondary coolant.

Many fluids have been used as volatile refrigerants in the evaporation, compression, condensing, and expansion cycle. This chapter will deal with application and structural design of piping for the more commonly used volatile refrigerants such as ammonia and some of the halogenated hydrocarbons. It will also cover general methods for other refrigerants where specific tables are not presented. Since volatile refrigerants are used in the liquid, vapor, and mixture phases, each of these will be treated separately.

Many fluids have been used...