Feature
COMPRESSORS AND
THEIR CONTINUAL DEVELOPMENT
By Ntsako Khosa
Compressors play a crucial role in ensuring an HVAC unit works effectively.
An air conditioner compressor is used to remove the
heat-laden vapour refrigerant from the evaporator of the
air conditioning system. In laymen's terms, the compressor
compresses or squeezes the vapour into a smaller volume at a
higher temperature.
The external-drive compressor has a crankshaft that is driven
by a pulley and belt system. An electric motor can also be used
to drive it directly. The hermetic compressor has a motor which is
sealed inside a housing with the compressor, hence a crankshaft
seal is not required. The motor rotor is located either at the top or
bottom of the unit.
“Selecting the correct compressor for an application will
depend entirely on the design application criteria, however, the
type of compressor may vary between residential, commercial
and industrial applications,” says Alistair Bell, Technical Sales
Engineer at Danfoss.
There are five types of air conditioner compressor that are
commonly used in the HVAC industry as Bell explains:
• Reciprocating: The most commonly used can be used
in appliances, residential A/C, light commercial A/C,
commercial A/C, refrigeration, and industrial applications
• Rotary: Can be used in appliances and residential A/C units.
• Scroll: Can be used in residential, light commercial A/C,
commercial A/C, and refrigeration applications.
• Screw: Can be used in commercial A/C, refrigeration, and
industrial applications.
• Centrifugal: Can be used in commercial A/C systems.
“Compressor technology has undergone significant
developments in the last hundred years. Almost all the
compressors mentioned in this article have reached a high level
of perfection. Today, different compressors are available for
different applications, starting from small hermetic reciprocating
and rotary compressors for domestic refrigerators to very large
screw and centrifugal compressors for huge industrial and
commercial refrigeration and air conditioning applications.
If all your
data is in
line with the
manufacturer’s
specifications,
your
compressor
runs well.
IMD
18
RACA Journal I August 2020
www.hvacronline.co.za