The document summarizes Heat-of-Compression (HOC) air dryers from Ingersoll-Rand. HOC dryers are the most energy efficient dryers that use recovered heat from air compression to dry the air. They provide dry air using virtually no energy. The H-Series dryer requires only 24 watts to power controls while the HC-Series provides extremely low dew points below -40°F through a stripping and cooling cycle. Both dryers minimize moisture problems and costs while maximizing reliability, productivity, and safety.
2. Air Quality Solutions by Ingersoll-Rand
HC Dryer
configuration
Introduction
Heat-of-compression dryers are dual tower, desiccant
designs. The HOC dryer is the most energy efficient
dryer available. It recovers the heat that is a natural by-
product of the compression process. This “free” heat is
utilized in the air drying process to provide moisture-free
air while consuming virtually no energy.
Reliability
Ingersoll-Rand heat-of-compression dryers, both
H-Series and HC-Series, are the world’s simplest,
and most reliable regenerative dryers. Their design
innovation, coupled with unsurpassed
performance, will help assure the reliability of
your compressed air system.
• The Ingersoll-Rand®
HOC dryer includes
proven high-performance 2-way valves,
providing years of trouble-free operation.
• The unique design of the HOC dryer, with
its stripping and cooling cycles, enables it
to achieve year-round dew points below
-40° F (-40° C).
• The HOC dryer is equipped with a
microprocessor-based control system
that maintains performance and monitors
the health of the unit, so downtime is
minimized.
• H- and HC-Series dryers can be
installed with multiple compressors,
allowing maximum flexibility without
sacrificing the integrity of the compressed
air system.
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2-Way Valve
3. Heatless
Refrigerated
Externally
Heated
Blower
Purge
I-R
HC-Series
I-RH-Series
Energy Costs
Energy Efficiency
Heat-of-compression dryers are the most cost-
effective means to protect air lines, tools and
expensive instrumentation. The H-Series dryer
does not use any heaters or blowers. The only
operating cost is for electricity needed to power
the microprocessor controls, which is less than
24 watts – the equivalent of a light bulb.
• The H-Series averages less than $10 per
year in total electrical cost, because there are
no heaters or blowers.
• The H-Series design consumes no valuable
compressed air.
• The HC-Series can constantly provide
-40° F (-40° C) or lower dew points, at a
fraction of the cost associated with other
regenerative type dryers.
• The HOC dryer is designed to minimize
pressure drop by utilizing full flow valves and
minimal piping.
No other compressed air
dryer can deliver dry air at so
low an annual operating cost
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4. Heat-Of-Compression Technology
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Two Dryer Solutions to Choose From
The H-Series dryer provides instrument air quality – and
with a very low initial cost.
The HC-Series is a more sophisticated dryer, which
includes a stripping and cooling cycle, delivering a
constant dew point without temperature or dew point
spikes.
Ingersoll-Rand can equip the dryer with a Dewpoint
Demand Controller which switches the towers only
on demand. This uses full capacity of the desiccant,
reducing the number of tower shifts and compensates
for fluctuations in flow.
H-Series Operation
The H-Series design provides efficient
operation by allowing air to enter the dryer
directly from the compressor. It is channeled
into the regenerating tower, where the heat
of compression removes the moisture from
the desiccant.
The air next flows into the aftercooler, then
separator, and finally into the drying tower,
where the air is dried to its final low dew
point.
AFTERCOOLER
LEFT TOWER
OUTLET-Dry Air
INLET-Hot Air
RIGHT TOWER
SEPARATOR
NO LOSS
DRAIN TRAP
(Regenerating) (Drying)
5. 5
HC-Series Operation
Left Tower Heating (see Fig. 1)
During the heating cycle, hot air from the
compressor is directed into the regeneration tower
through 2-way valves. There, the hot, thirsty air
removes the bulk of the water from the desiccant.
The air then enters the aftercooler, where it is
cooled. Water is then removed through a moisture
separator and no loss drain trap. Finally, the air
enters the drying tower, where it is dried to its final
dew point.
Left Tower Stripping (see Fig. 2)
The stripping phase of regeneration occurs after
full flow heating and typically lasts 90 minutes.
At the beginning, the regenerating tower is
depressurized through a muffler. During stripping,
a small amount of dry air is used to remove the
residual moisture from the regenerating tower.
This enables the HC-Series design to provide
such exceptionally low dew points.
Left Tower Cooling (see Fig. 3)
At the end of stripping, the regenerating tower is
repressurized and cooling begins. During cooling,
a portion of dry outlet air is directed into the
regenerating tower to reduce the temperature
of the bed. There is no air lost during cooling.
Cooling and stripping combine to provide
extremely low dew points and eliminate dew point
and temperature fluctuations during tower shift.
AFTERCOOLER
LEFT TOWER
OUTLET-Dry Air
INLET-Hot Air
RIGHT TOWER
SEPARATOR
NO LOSS
DRAIN TRAP
PURGE
EXHAUST
(Regenerating) (Drying)
AFTERCOOLER
LEFT TOWER
OUTLET-Dry Air
INLET-Hot Air
RIGHT TOWER
SEPARATOR
NO LOSS
DRAIN TRAP
PURGE
EXHAUST
(Stripping) (Drying)(Drying)(Drying)
AFTERCOOLER
LEFT TOWER
OUTLET-Dry Air
INLET-Hot Air
RIGHT TOWER
SEPARATOR
NO LOSS
DRAIN TRAP
PURGE
EXHAUST
(Cooling) (Drying)
Fig. 3
Fig. 1
Fig. 2
6. Productivity
The problems created by moisture contamination in a
compresser air system include rust and corrosion in the
air piping, inadequate air tool lubrication, and damage to
labeling, packaging and the finished goods. The HOC
dryer can prevent such productivity losses throughout
your operation by delivering a continuously low dewpoint.
• The H-Series dryer can deliver points in the 0° F
(-18° C) to -60° F (-51° C) range depending on the
operating conditions. The H-Series dryer delivers
better than instrument quality air to eliminate moisture
problems.
• With its patented stripping and cooling cycles, the
HC-Series dryer can produce continuous year-round
dew points of -40° F (-40° C) and below.
• Both the H- and HC-Series dryers prevent
costly production interruptions due to moisture
contamination.
Health, Safety and Environment
Ingersoll-Rand HOC dryers are designed to protect the
health and safety of the operators and the environment
in which they are installed.
• Dryers utilize a non-acidic desiccant and no ozone
depleting refrigerants.
• Insulated towers protect operators from hot surfaces.
• The HOC dryer is a packaged design, with all
components pre-piped and pre-wired. This eliminates
costly installation charges and minimizes floor space
requirements.
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