SRC Service Manual
Revision 02
Aug 2007
1. General Description
The SRC Cycling Refrigerated Air Dryer reduces the dew point
(1)
of compressed air stream by reducing the temperature causing
water and oil vapour (along with other evaporated contaminants)
to condense into a liquid. These liquids are then separated from
the air and discharged from the system. The dry air is then re-
heated before continuing downstream.
Air streams are measured in terms of their flow, temperature and
pressure. These variables fluctuate continuously throughout the
day and can change drastically throughout the year, depending
on the climate, conditions, and application. As they change, so
does the amount of heat in the air (called the “heat load”) and
therefore the amount of moisture the air stream can carry.
Every refrigerated air dryer is designed to handle a maximum
incoming heat load. At any heat load below the maximum, there
is the potential for saving energy as the dryer is absorbing less
heat, that it is designed for.
The SRC is a “cycling” dryer, because it reduces it’s power
consumption at reduced heat loads by cooling the air using a large tank of a cold glycol & water
mixture (referred to as a thermal mass), which is in turn cooled by a refrigeration system. When there
is less heat load, the thermal mass absorbs less heat, and the refrigerant system is
cycled
on and off
only as necessary to keep the thermal mass cold. This absorbs less energy than traditional non-
cycling dryers which do not use a thermal mass, and therefore must run their refrigeration system
continuously all the time.
(1) Dew point – a measurement of the amount of moisture in a gas, indicated as the temperature at which
the air would be saturated (i.e. the relative humidity would be 100%) and liquid condensate would begin
to form. It is commonly shown as
o
F or
o
C. It is important when discussing dew point to specify if you are
referring to the “pressure dew point” (the dew point at the pressure of the system) or “atmospheric dew
point” (the dew point at atmospheric pressure) as the two are significantly different.
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