The document discusses heat recovery in compressed air systems, highlighting that significant energy is wasted during operation due to leaks and improper heat recovery. It compares air-cooled and water-cooled systems, noting that water-cooled oil-injected systems are the most efficient due to their favorable temperature profiles. Ultimately, optimizing heat recovery can improve energy efficiency and reduce operational costs.

1. z
HEAT
RECOVERY &
COMPRESSED
AIR SYSTEMS

2. z
INTRODUCTION
94%
6%
Waste Energy
Electricity
consumed by the
compressor
Compressed air
delivered by
compressor
Heat Loss
Wasted air due to :
• Leaks
• Artificial demand
• inappropriate
Heat recovery in compressed air
systems is a process that utilizes
the heat generated during the
compression of air to improve
energy efficiency and reduce costs
What to do? HEAT
RECOVERY

3. z
AIR COOLED
METHOD HARVEST HEAT
 OIL FREE
 OIL INJECTED
WATER
COOLED
 OIL FREE
 OIL INJECTED

4. z
AIR-COOLED
 The hot air is used to heat up the room
and the adjacent areas
 In an air-cooled system, the hot air
temperature can range from 17°C to 25°C
higher than the ambient air temperature.
 The temperature range applies to both
oil-free and oil-injected.
Ambient air
Hot air

5. z
WATER-COOLED
OIL-FREE
 Oil-free signifies that it
doesn't use oil for lubrication
in the compression chamber.
 Typically, Chilled Water
Return (CWR) temperatures
are around 80°C, but some
companies may achieve
temperatures as high as 90°C
OIL-INJECTED
 Function is to cool and lubricate
the compressor element's
moving parts and the air being
compressed internally.
 Chilled Water Return (CWR)
temperatures generally hover
around 70°C, although certain
companies can reach
temperatures as low as 60°C.
cws
cws

6. z
CONCLUSION
 AIR-COOLED (OIL-FREE)
 AIR-COOLED (OIL-INJECTED)
 WATER-COOLED (OIL-FREE)
 WATER-COOLED (OIL-INJECTED)
Air ambient + (17°C - 25 °C)
80°C / 90 °C
60°C / 70 °C
In conclusion, among the four methods for heat recovery in air compressors, the water-
cooled oil-injected system stands out as the most favourable choice. This preference is
primarily due to its temperature profile, which is notably well-aligned with the project's
requirements, ensuring accuracy and optimal efficiency.