Air Conditioning Fundamentals
TC070-05-01S
6 – REFRIGERATION
CYCLE
46
After picking up heat in the evaporator, the refrigerant gas is drawn into
the inlet side of the compressor, where it begins another refrigeration
cycle.
Orifice Tube System
An orifice tube system works similar to an expansion valve system.
However, since the orifice tube is a fixed size, the tube must flood the
evaporator to work properly under all conditions. As the refrigerant
passes through the evaporator, most of it changes into vapor and then
travels to the accumulator, as shown in Figure 27.
As we discussed before, the accumulator replaces the receiver / dryer
in the system. The accumulator separates the liquid refrigerant from the
refrigerant vapor. This prevents liquid refrigerant from getting back into
the compressor, and allows higher heat loads by keeping the remaining
liquid on hand.
FIGURE 27. As the
refrigerant passes
through the
evaporator, most
of it changes into
vapor and then
travels to the
accumulator.
Compressor
Condenser
Accumulator
Orifice tube
Evaporator
High pressure vapor
Low pressure vapor
High pressure liquid
Low pressure liquid