Bally Refrigerated Boxes BVC Generation C – Direct Drive Air-Cooled – Vertical Air - Manual (Page 20)

The purpose of a refrigeration system is to absorb
heat from an area where it is not wanted and reject
this heat to an area where it is unobjectionable.
By referring to the diagram below, it can be seen
that only a few components are required to perform
this task.
High pressure/high temperature vapor leaves the
compressor and is forced into the condenser via the
discharge line. The condenser first desuperheats the
vapor down to its saturation point. This saturation
point can be expressed as the condensing
temperature of the refrigerant and varies with
condenser size, load and ambient temperature.
Now the condenser must remove the latent heat of
condensation from the refrigerant so that it may fully
condense. After the refrigerant has fully condensed,
it will be subcooled to some extent.
CONDENSER THEORY
The liquid leaving the condenser is still at a high
pressure but at a much lower temperature and drains
into the receiver. As the liquid level in the receiver
increases, the vapor is allowed to vent back up to the
condenser via the condensate line.
Because the dip tube almost reaches the bottom of the
receiver, only liquid will enter the liquid line. This liquid
now passes through the metering device where its
pressure is reduced to the evaporating pressure.
The temperature will drop with pressure since the
refrigerant will always attempt to meet its saturation
point during a change of state.
The condensing temperature decreases as the
ambient temperature drops and/or as the condenser
surface increases.
- 20 -
THE BASIC REFRIGERATION CYCLE