part 1 condensing theory - ashraeuae.org
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CONDENSATION TECHNIQUE
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O2
CH4
O2
H2O
CO2
H2O
Condensing Technology Part 1: Theory
Simplified chemical equation for combustion
CONDENSATION TECHNIQUE
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Higher and lower calorific/heating value
Two different calorific values in fuels:
1. Higher calorific/heating value (HCV)
the total amount of heat released during combustion, therefore also the latent heat of the water vapour of the discharged flues.
HCV = sensible heat + latent heat (or “hidden”)
2. Lower calorific/heating value (LCV)
the sensible heat that can be recovered from combustion without condensation.
LCV = sensible heat
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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Latent heat = 11% of gas combustion energy
Condensing Technology
CONDENSATION TECHNIQUE
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Non-condensing boiler thermal overview Latent heat completely lost
• Qc thermal load pci*mc/h
• Qf flues loss in sensible heat
• Tf flues gross temperature
• Ta comburent air temperature
• CO2 % in flues
• f coefficient on fuel
• Qu working power
• Qd wet parts casing loss
• Qds dry parts thermal lossQc
QuQd + Qds
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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How to recover the Latent heat?
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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DEW POINT temperature, according fuel type
57
Natural Gas (95% CH4) Light Oil Con
de
nsin
g te
mp
era
ture
wa
ter
va
po
r [°
C]
Amount of CO2 [Vol. %]
Condensing Technology Part 1: Theory
10.5
CONDENSATION TECHNIQUE
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We need to cool down flue gases < 57°C
How to do:
1. More efficient boiler’s heat exchanger
the total amount of heat released during combustion, therefore also the latent heat of the water vapour of the discharged flues.
2. Water return at a temperature lower than 55°C
the best case is with water return temperature at 30°C
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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Positive side effects of a colder boiler
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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pci
pcipcsPPdf
C100
1
B
CO
ATTP aff
2
1)(
sensible heat latent heat
Condensing Technology Part 1: Theory
Total boiler efficiency
CONDENSATION TECHNIQUE
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Sensible heat loss
Pf = (tf - ta) * [(A1+B)/CO2]
conventional boilerPf = (190-15)*[(0,37+0,009)/10]
= 6,63 %
condensing boilerPf = (60-15)*[(0,37+0,009)/10]
= 1,8 %
around 5% difference
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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Condensing heat recovery, the “alpha” factor
Qcond = α* (HCV - LCV)
latent heat
light oil α
0,4 - 0,6
gas α
0,5 - 0,75
0,5 * 6% = 3% 0,6 * 11% = 7%
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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Total efficiency increase
Sensible heat increase on Pf and Pd
(lower flues temperature )
light oil gas
SENSIBLE 5% SENSIBLE 5%
+ +LATENT 3% LATENT 7%
_________________ __________________
TOTAL = 8% TOTAL = 12%
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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Example of condensing boiler efficiency
7.1040.77.97%
7.9765.035.10
35.1046.11
100
5.08.11%
2.98100
8.11%
condens
comb
SENSIBLE HEAT LATENT HEAT
97.7 7.0
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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Factors affecting condensation use
Condensationuse
ηHydraulic
connections
Boiler
design
characteristics
Fuel
Heating
system
Subsidy
Regulations
Laws
Return
temperature θand
load factor Ф
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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Comparing efficiencies (LCV)
Condensing boilers
High efficiency conventional boilers
Efficiency of standard boilers in 1975
Seaso
na
l eff
icie
nc
y [
%]
Boiler load [%]
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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Increasing efficiency in condensing boilers
- Latent heat recovery for condensation
- less dissipation through discharge gases
discharge flues temperature is lower, because sensible heat is completely transferred to the water inside the boiler
- lower dispersions for radiation
because the temperature of boiler water is lower
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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What about condensate water?
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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Condensing formation with different fuels
With the complete
condensation of
1 m3 of natural gas
it is possible
to recover:
1 kW
resulting in more11% heat and
1,6 litres
of condensate water
Higher calorific value. PCS
kWh/m3
Lower calorific
value. PCSkWh/m3
HCV/LCV HCV/LCVkWh/m3
theoretic condensation
kg/m3
district gas 5,48 4,87 1,13 0,61 0,89
nat. gas L 9,78 8,83 1,11 1,04 1,53
nat. HCH4
11,46 10,35 1,11 1,11 1,63
propanC3H8
28,28 25,99 1,09 2,29 3,37
buthan 37,22 34,31 1,08 2,91 4,29
light oil 10,68 10,08 1,06 0,60 0,88
Condensing Technology Part 1: Theory
CONDENSATION TECHNIQUE
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Comparing pH values in nature
Light oil Natural gas Domestic water
Lemon juice
Rainwater Distilled
water
Seawater
Condensate from
condensing boiler
pH Value
Acid
Acid accumulator
Basic
Ammonia
Condensing Technology Part 1: Theory
Condensate water is acid
CONDENSATION TECHNIQUE
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Materials used for condensing boilers
Stainless steel (AISI 316L or similar)
Condensing Technology Part 1: Theory
Aluminum alloy (Al-Si-Mg)
Corrosion resistant materials
CONDENSATION TECHNIQUE
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Condensing Technology Part 2: Boiler features
Part 2:
Technical features
and Applications
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Stainless steel – High water content
Condensing Technology
Capacities from 50 kW up to 2,000+ kW
Part 2: Boiler features
Same general features as conventional boilers, but more efficient.
CONDENSATION TECHNIQUE
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Aluminum alloy – Low water content
Condensing Technology
Capacities from 50 kW up to 900 kW with modular system
Part 2: Boiler features
A combustion chamber with burner, fan, gas valve and ignition
device is called module. A boiler can be made of many modules.
CONDENSATION TECHNIQUE
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Condensing Technology
Model FS 981 488 GTB
Year 1922 2015
Power [HP] 530 670
Max speed [km/h] 40 360
Lenght [mm] 9,160 4,568
Weight [kg] 47,200 1,475
Engine made of Steel Aluminum
The opportunities of aluminum
Part 2: Boiler features
CONDENSATION TECHNIQUE
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Condensing Technology Part 2: Boiler features
ReliabilityNew concept of backup boiler
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Backup boiler
Condensing Technology Part 2: Boiler features
Many plants are designed with a few boilers on duty
plus one as backup
- In case of boiler failure.
- In case of pick load demand
- etc
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Up to 8 independent boilers in one
- The boiler’s capacity is usually
calculated according plant’s
max load.
- With a failure of one module
out of 4, it’s granted 75% of its
capacity
- This is not possible in boilers
with one burner only
Condensing Technology Part 2: Boiler features
If there is a failure in one or more modules, the other ones will
work normally.
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Emergency functions
Condensing Technology Part 2: Boiler features
A. Emergency operation in case of
breakdown to the thermo-controller
E8, with activation of the heat
request at constant setpoint with
maximum capacity of 50%
B. Reset burner lockout
C. Remote alarm relay
D. ModBUS integrated
CONDENSATION TECHNIQUE
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Condensing Technology Part 2: Boiler features
Modulationand cascade manager
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Modulation
Condensing Technology Part 2: Boiler features
With several burners in one boiler is possible to achieve a
turn-down ratio impossible for single-burner models.
Turn-down modulation ratio up to 1:39
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Modulation
Condensing Technology Part 2: Boiler features
1 module
100 % = 48 kW
1 module
38 % = 18
kW
108,2
18
100% =104. 9
pot. min = 108.4
P (kW)10
93
97103
109
(% pci)
20 30
T. Flow = 50°C
T. Return =
30°C
50
T. Flow = 80°C
T. Return =
60°C
1st decide the power and divide for the maximum n° of available
burner in order to work on the best efficiency point
2nd the cascade depending also to the working time of each
burner in order to have the same running time for every burner
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Modulation
Condensing Technology Part 2: Boiler features
12 22 22 22 22 22
150
200
250
300
350
432
540
648
756
864
12 12 121212
100
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
E X
T 1
00
E X
T 1
50
E X
T 2
00
E X
T 2
50
E X
T 3
00
E X
T 3
50
E X
T 4
40
E X
T 5
50
E X
T 6
60
E X
T 7
70
E X
T 9
00
MIN
MAX
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Cascade installation
Condensing Technology Part 2: Boiler features
With the cascade installation, the boiler output range can be
widened well over 900 kW, so multiplying output and modulation in
order to satisfy any design demand.
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Condensing Technology Part 2: Boiler features
Pollution
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Polluting emissions
Combustion polluting emissions:
- Dust or particulate
- Volatile Hydrocarbons CxHy
- Sulphur Oxides, SOx
- Carbon Oxide, CO
- Nitrogen Oxides, NOx (NO 90-95% e NO2 5-10%)
Condensing Technology Part 2: Boiler features
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CO2 fuel emissions
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0,4
0,45
1
charcoal
hard coal
heavy oil
gas oil
natural gas
Condensing Technology Part 2: Boiler features
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NOx formation (ozone and acid rain)
Thermal NOx
Permanence time
O2 partial pressure
Flame temperature
Formation procedure
Thermal
NOx
Available
NOx
Fuel
NOx
Nitrogen oxide and dioxide
formation
Condensing Technology Part 2: Boiler features
CONDENSATION TECHNIQUE
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NOx formation
• In natural gas fuel, NOx
are practically absent;
• 90% comes from thermal
Nox: produced at the head
of the flame due to the
oxidation of the nitrogen
present in the air; the
process is highly
influenced by the
temperature.
Condensing Technology Part 2: Boiler features
Reverse flame boilers are the most polluting.
CONDENSATION TECHNIQUE
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NOx formationIncidence factors
Partial O2 pressure: less O2 quantity in reaction zone less NOx formation
Condensing Technology Part 2: Boiler features
CONDENSATION TECHNIQUE
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Condensing Technology Part 2: Boiler features
Air Filter
Smoke non return valve
Modulating Fan
Gas valve and Premix
Multigas
Burner
MODULE
(CASTING IN Al-Si-Mg)
Fla
me
Wate
r
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Condensing Technology Part 2: Boiler features
Non-return valve
Air
Air
Air
Gas
Gas
Mix Air/Gas
Mix Air/Gas
PREMIX burner: the right quantity of air and gas is taken, mixed by the fan, then
pushed through the non-return valve to the burner for a perfect combustion
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Combustion polluting emissions
- Emission < 35 ppm (NOx)
- Acoustic < 50 db (A)
Condensing Technology Part 2: Boiler features
The exhaust gases are immediately cooled down
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Condensing Technology Part 2: Boiler features
Installationnew revolutionary opportunities
CONDENSATION TECHNIQUE
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Boiler weight. Steel boiler vs aluminum boiler
Condensing Technology Part 2: Boiler features
350 kW boilers
Model 350 kW Reverse flame steel
boiler
Aluminum boiler
Boiler net weight [kg] 630 419
Water content [liters] 300 31
Boiler total weight [kg] 930 (without burner) 450 (burners included)
Large water content steel boilers, double the weight (or more) than aluminum boilers
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Extremely compact: 1 MW on 1.5 m2 footprint
Condensing Technology Part 2: Boiler features1150 m
m
1448 m
m
CONDENSATION TECHNIQUE
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Space saving
Condensing Technology Part 2: Boiler features
Sede Gas Natural-
Fenosa
Av. San Luis
(Madrid)
4x 900 Kw: 3600Kw
Minimum gap allowed between boilers is 40 cm only
Boiler room above is 3.5 MW in 20 m2 (5x4 m)
CONDENSATION TECHNIQUE
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Waterproof casing IP 5x
Condensing Technology Part 2: Boiler features
Pneumatic control panel opening
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Installation on rooftop
Condensing Technology Part 2: Boiler features
Advantages:
- Easier plant design
- Short chimney
- Reduced piping
No need of boiler room:
- Save valuable space
- Reduced safety requirements
Just beside chillers
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Disassemble – pass through - assemble
Condensing Technology Part 2: Boiler features
Aluminum boilers are assembled, not welded.
CONDENSATION TECHNIQUE
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Compact containerized installation
Condensing Technology Part 2: Boiler features
CONDENSATION TECHNIQUE
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Solar panels and calorifiers integration
Condensing Technology Part 2: Boiler features
CONDENSATION TECHNIQUE
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MODULEX: 15 pantent claims
Condensing Technology Part 3: MODULEX
CONDENSATION TECHNIQUE
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MODULEX: BEYOND CONDENSING
Condensing Technology Part 3: MODULEX
GREEN BUILDING
- Emission <35 ppm (NOx),
- Acoustic <50 db (A)
RELIABILITY
- Built-in backup (several independent modules)
- 50% of capacity in Manual mode
- BMS and Remote alarm integrated
NEW INSTALLATION OPTIONS
- Outdoor / rooftop installation
- Compact solutions – space saving
HIGH EFFICIENCY
- Up to 109% efficiency
- Up to 1:39 turn down modulation
CONDENSATION TECHNIQUE
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Apple store 5th Avenue - New York
Condensing Technology References
CONDENSATION TECHNIQUE
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His Highness Prince Ali - Jordan
Condensing Technology References
CONDENSATION TECHNIQUE
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National library - Alexandria of Egypt
Condensing Technology References
CONDENSATION TECHNIQUE
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Renoult Cleon - FRANCE
Condensing Technology References
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Condensing Technology Iconic global references
- AUSTRALIA: Hospital "AUSTIN" - Melbourne.
- AUSTRALIA: Crown Plaza – Casino & Luxury hotel.
- LATVIA: Ministry of Defence
- RUSSIA: KRASNODAR Palace
- IRAN: Shopping mall - Teheran
- ITALY: WHIRPOOL factory
- VATICAN (Rome): Pope’s palace