2. T w o B a s ic P r in c ip a ls o f A ir o r G a s C o m p r e s s io n
P o s it i v e D i s p l a c e m e n t D y n a m ic C o m p r e s s i o n
C o m p r e s s o r s
Compressor Types
3. reducing the volume of a
gas
increases its pressure
positive displacement principle
6. Working Principal
•Wheel turns
•Air molecules are
accelerated through
the wheel
•Air molecules are
discharged at a high
velocity
Blade
ZH Compressor Fundamentals
10. WORKING PRINCIPLES
Variables influencingVariables influencing
compressor performancecompressor performance
• Positive displacementPositive displacement
compressorscompressors
Where: P : Power
P1 : Inlet pressure
V1 : Inlet volume
n : Adiabatic factor
P2/P1 : Pressure ratio
Variables influencing power:
P1 = Inlet pressure
V1 = Volume flow (not mass!)
P2/P1 = Pressure ratio
Inlet air temperature andInlet air temperature and
mass flow (density) havemass flow (density) have
no effect on powerno effect on power
P = P1
.
V1
. .
{( ) -1 }
n
n-1
P2
P1
n-1
n
11. WORKING PRINCIPLES
Variables influencingVariables influencing
compressor performancecompressor performance
• DynamicDynamic
compressorscompressors
Where: H : isentropic Head
R : real Gas constant
T1 : Inlet temperature
k : Spec heat ratio cp/cv
P2/P1 : Pressure ratio
H = R .
T1
. .
{( ) -1 }k
k-1
P2
P1
k-1
k
Inlet air temperature andInlet air temperature and
mass flow (density) havemass flow (density) have
direct effect on powerdirect effect on power
18. Pressure depends on the
speed at which the air
leaves the impeller
Pressure cut:
• reduced wheel diameter
• only last stage
Pressure variantsPressure variants
STAGING
23. SURGESURGE
Breakdown of gasflow due to high back
pressure
(oscillation flow)
STONE WALL (choke)STONE WALL (choke)
Maximum flow a compressor can handle
at a given speed
THEORY
24. What is
surge ??? A dynamic instability that occurs in a compressor
causing a momentary flow backwards
It happens when the combination of flow and velocity
is not large enough to develop the
required discharge pressure
The unit produces a loud screaming noise and
Causes severe stresses
Generates excessive heat
THEORY
25. Surge control
Control system tries to avoid that unit
operates in the surge area.
Surge protection
If the unit surges, it is detected and the
unit is switched to unload.
THEORY
31. Greater operating flexibility
with turndown ratio up to 35%
Power savings at fluctuating
air demand
Longevity in operation with
stainless steel impellers
Ensured reliable operation
Impellers are tested at 115%
of max. speed
Exclusive backward
lean impeller design
Control line
% Flow
%DischargePressure
Surge limit
By-pass Turn-down range
ZH Design
39. Improved resistance against poor
water quality
Cooler Tube Bundles
Stainless steel bundle
tubes and end plates
stainless steel tubes for
higher resistance to
corrosion
tubes with aluminium fins for
extended exchange surface
thus low air approach
temperature
40. High efficiency intercoolers
Intercoolers separated from
the compressor core unit for
higher reliability and easier
maintenance
low air approach
temperature and pressure
drop thanks to optimized air
flow pattern through the
shells and bundles
Air Circuit: Intercoolers
41. Intercooler shells
full epoxy coating inside the shells
for enhanced resistance to
corrosion
flexible connections to the
interstage piping for easy
inspection & maintenance
High efficiency condensate
separation, up to 99%
low velocity leaving the cooler
bundle and optimized outlet
port shape lead to natural
condensate separation
Air Circuit: Intercoolers
42. Condensate drain traps
• mounted on
intercoolers and
aftercooler with manual
by-pass valves
• drains with bigger fluid
reservoir for dirt
sedimentation
Water Circuit: Condensate Drain Traps
47. Environmentally friendly
motorized oil demister prevents oil fumes
leaking to the atmosphere
Low energy consumption +/- 90 W
Easy for
maintenance
Oil Demister
49. ZH Capacity Regulation
There are three different modes of regulation
available on the ZH series compressors
Full Load – No Load
- 100% or 0% output
Auto Dual
- 100% - 65% or 0% output
Modulating Control
- 100% - 65% then modulating blow off down to about
10%
50. IGV’s
IGV’s are cycled by a 4-
20mA signal send from the
PLC
The valve must be adjusted
on start-up and should be
check on an annual
4mA = Valve Closed
20mA = Valve fully open
When the valve is closed
the hole in center allows
the compressor to have a
small amount of air flow
that is blown off.
53. Inlet pressure
Inlet air temperature
Cooling water temperature
Humidity (molecular weight)
INFLUENCE OF OPERATING PARAMETERS
54. Discharge
Pressure % 100
Power at
Coupling % 100
Inlet flow (weight/volume) percent 100
Decrease in inlet pressure
reduces flow
Decrease in inlet pressure
reduces power required
Inlet pressure influenceInlet pressure influence
INFLUENCE OF OPERATING PARAMETERS
55. Inlet air temperature influenceInlet air temperature influence
Discharge
Pressure %
Power at
Coupling %
Inlet flow (weight/volume) % 100
Decrease in air temperature
increases flow
Decrease in air temperature
increases power
Increase in air temperature
reduces flow
Increase in air temperature
reduces power
Surge
line
Design point
100
100
INFLUENCE OF OPERATING PARAMETERS
56. Discharge
Pressure % 100
Power at
Coupling % 100
Inlet flow (weight/volume) % 100
Colder water
increases flow
Colder water increases
power requirement
Warmer water
decreases flow
Warmer water decreases
power requirement
Surge
line
Cooling water temperature influenceCooling water temperature influence
INFLUENCE OF OPERATING PARAMETERS
57. Discharge
Pressure %
Power at
Coupling %
Inlet flow (weight/volume) % 100
Increase in mole weight
increases flow
Increase in mole weight
increases power
Decrease in mole weight
reduces flow
Decrease in mole weight
reduces power
Surge
line
Design point
Molecular weight influenceMolecular weight influence
100
100
INFLUENCE OF OPERATING PARAMETERS
62. The hardware
compact electronic controller,
microprocessor based, with a
real time operating system
stabilized 24 V AC, wide
voltage band power supply
(-30% to + 40%)
ergonomic user interface
(3xLEDs, easy to read alfa-
numeric display, high quality
push buttons)
Elektronikon
63. Energy efficiency
precise pressure control
as standard the energy saving
running mode DSS (Delayed
Second Stop) is preprogrammed
DSS avoids the unload time to
the maximum extent by
anticipating on pressure
fluctuations in the system
energy savings up to 10% are
feasible
Elektronikon
0
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
64. Reliability
controls and monitors
compressor and integrated
ancillaries
- protects compressor
and surroundings via automatic
shut-down
in case of a fault in a vital
function
- gives warnings well before shut-
down, so proactive
measurements can be taken
Elektronikon®
65. Service friendliness
- monitors service intervals
- generates service ‘WARNING’
messages
- easy troubleshooting and fault-
diagnosis
Elektronikon®
72. Flow
system header
multi turbo installation
Important:
staggered entry of units directly opposite
each other on header required
PipingPiping
Piping
73. PipingPiping
Turbo downstream of air receiver
* connection to system header with - long radius elbow
- or angle in flow direction
Recip
Screw
Turbo Turbo
or
Air receiver
* *
or
Flow
Piping
74. x
compressor discharge connection to header
Flow Header
from compressor
Not connectedNot connected
to the bottomto the bottom
but
from
compressor header
Flow
or
header
Flow
from
compressor
PipingPiping
Piping
WHY IS ENERGY SO IMPORTANT?
In the depiction of the life cycle costs in the diagram above,we see that energy constitutes the major portion, where as investments and maintenance occupy less than 30% of the costs.
Consequently savings in energy bring about a large difference in the overall life cycle costs of the machine
