TYPES OF EVAPORATORS
Two main categories of evaporators used in industrial refrigeration practices air coil and liquid coolers. A typical air coil shown in Fig. 6.2 and several types of liquid coolers are shown in Fig. 6.3. In the air coil, refrigerant passes through the pipes and air passes outside the tube. For efficient heat transfer fins attached to the external surface of pipes and air currents between the ribs.
Liquid cooling evaporators in Fig. 6.3a and 6.3b are shell-and-tube design, and in Fig. 6.3c-plate cooler. On Fig. 6.3a refrigerant boiling in the shell while the liquid flows through the pipes. On Fig. 6.3b role of pipes and shell reversed. The plate-type evaporator in Fig. 6.3c growing market share and adaptation of plate heat exchangers used for many years in the food industry. Some of its popularity is its compactness, and that the refrigerant is less than shell-and-tube evaporator. The reduced charge of characteristic is attractive when ammonia and new chlorine refrigerants are used. The charge level of ammonia system is desir
able for security reasons, and the charge of chlorine system minimizes the cost of these expensive refrigerants.
This Chapter is divided into three parts: Part I, Evaporator Performance, addresses the principles applicable to all types of evaporators; Part II, Air Coil, treats evaporators used for air cooling and Part III, liquid Chillers, concentrates on evaporators that put in the refrigerator water, brines, antifreeze and other liquids.