Hillphoenix Adaptapak ADP-M0000-L0032, Installation And Operation Manual

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AdaptaPAK® Parallel Refrigeration System
Section 2:
DX Refrigeration Systems
Direct expansion (DX) refrigeration is one of the most common methods
used for the removal of heat. Such a system takes heat from a place where
it is unwanted and removes it to a place where it is unobjectionable. The
Hillphoenix® AdaptaPAK® units utilize DX refrigeration to remove heat from
store display cases and walk-in coolers/freezers, and transfer it to an outdoor location where it can be rejected.
Refrigeration Through Vapor Compression
Refrigeration is accomplished through application of various mechanical principles that occur as part of a
continuous cycle, commonly known as the Vapor Compression Refrigeration Cycle.
In the vapor compression cycle, heat is absorbed as the liquid refrigerant in the evaporator changes to a vapor. The
refrigerant boils at the new saturation point in the evaporator (located in the display case or cooler) where it changes
to a superheated vapor. From the evaporator, the superheated refrigerant vapor enters the compressor and the
refrigerant is compressed and changed from a low pressure superheated vapor to a high pressure superheated
vapor (more on this later), It then flows to the condenser. In a simple refrigeration system, the ambient air outside of
the condenser flows through the coils of the condenser where it absorbs heat from the vapor refrigerant causing it to
change back to its liquid state before moving through the metering device where it crosses from the high pressure
side of the system to the low pressure side. On the low pressure side, the refrigerant returns to the evaporator and
the process (refrigeration cycle) is then repeated.
Refrigeration System Components
Knowing how the refrigeration process works helps in understanding where in the sequence of operation the major
components of the mechanical system are, and the functions they perform. Almost any refrigeration system is built
around four main components.
The four main components are:
•
Compressor
•
Condenser
•
Metering Device (also known as an expansion valve)
•
Evaporator
Beginning on the next page, these main components are individually presented and discussed.