burner retrofits: opportunities yielding worthwhile paybacks
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Burner Retrofits:
Opportunities Yielding Worthwhile Paybacks
Norbert Hennrich
March 9, 2016
High Efficiency Burners
Agenda
• Boiler Efficiency
• Efficiency Losses
• Combustion Basics
• Tune-Up
• Turndown Ratio
• Key Factors for Maximum Efficiency
• Boiler Project Examples
Existing Boiler Market
• Boiler Population ≅ 400,000 units of commercial & industrial
boilers in North America
• Consumes 25% of the world’s energy
Existing Boiler Market
Boiler Age < 20 Years Old
(40%)
> 20 Years Old
(60%)
Efficiency (Based on HHV) Better than 75%
(40%)
Between 70-75%
(60%)
Potential Savings By increasing combustion efficiency by 10% there is a potential to save 400 million
barrels of oil equivalent per year.
15 billion $US wasted per year.
∆ barrel oil = 35 $US
Boiler Efficiency
1. Combustion Efficiency
• Higher levels of combustion efficiency can only be achieved when
fuel and air are properly mixed.
2. Flue Gas Temperature
• Dependent on boiler’s ability to absorb heat as well as on excess air
• Cleanliness of heat exchanger = big factor
3. Turn Down Ratio
• Equipment needs to be sized for the actual needed capacity to
eliminate unnecessary cycling (purging of air through the system.)
Efficiency Losses in a Boiler System
1%
100%
76% 20%
3%
Efficiency Losses in a Boiler System
• Radiant Losses (approx. 4%)
• Insulation of boiler jacket and insulation of pipes and valves
helps reduce radiant losses!
• Stack Losses (approx. 20%)
• Stack Temperature
• 35-40 ˚F increase equals approx. +1% in energy loss
• Combustion Efficiency
• Oxygen not used in combustion process = additional losses
• Turndown Ratio of Burner Equipment
• Purging & Boiler Cycling
Combustion Efficiency
Combustion Efficiency
Combustion
Chamber
Pressure
Air Pressure Air Temperature
To prevent a shortage of air being caused by external
factors, excess air is used for combustion
Excess air
+15…20%
Excess air = inert particles loss of heat
Fan Contamination Chimney Draught
Some Burners Use More than 100% Excess Air
Combustion Efficiency
Combustion with 15% Excess Air Combustion with 50% Excess Air
O2 Content: 3%
CO2 Content: 10%
Loss of Heat: Low
O2 Content: 7%
CO2 Content: 8%
Loss of Heat: High
Excess Air vs. Oxygen
Boiler Efficiency — Tune Up
Boiler HP Fuel Cost
$0.75 $1.00 $1.50 $2.00
100 $3,635 $4,847 $7,271 $9,694
200 $7,271 $9,694 $14,541 $19,389
300 $10,906 $14,541 $21,812 $29,083
500 $18,177 $24,236 $36,354 $48,471
800 $29,083 $38,777 $58,166 $77,554
Possible savings per year with a 5% improvement in boiler efficiency
(based on 3,000 hours per year of operation)
Although stack losses are unavoidable, an equipment tune-up using combustion analysis
data can often significantly reduce this source of heat loss and save fuel costs by
improving fuel efficiency.
Source: EPA.gov
Boiler Efficiency — Tune Up • The Usual Conclusion:
• Service and clean boiler/heat exchanger on a regular basis.
• Tune-up the burner to reduce excess air to the minimum of what the
boiler can use.
• What Else Can Be Done?
• A burner retrofit or boiler changeout!
• Why?
• To further increase the combustion efficiency through tighter 02
settings.
• Increase in Turndown Ratio (overall operating range of boiler
system.)
Boiler Efficiency — Turndown Ratio
• What is Turndown Ratio?
• Turndown is the burner’s ratio of capacity at
full fire compared to its lowest firing point
before shutdown.
• Boilers with a wider Turndown Ratio are
typically more efficient at meeting variable
loads.
• A properly sized boiler operation with a high
Turndown Ratio eliminates almost all purge
cycles.
Boiler Efficiency — Purge Cycles
• What are Purge Cycles?
• Boilers must run a purge cycle at the start of each on-cycle
to assure that there is no accumulation of explosive gases in
the fire box.
• By Code, enough air must be blown through the boiler to
perform an air exchange of 4x the volume of the fire box.
• This purging with cold air also removes heat from the boiler!
• Flames tend to be the most unstable and heat transfer is
at its lowest at start-up.
• Reducing the number of on-cycles increases boiler efficiency
and the life of the existing boiler by eliminating stress on the
boiler vessel.
Heating Loss Due to Purge Cycles
Number of Cycles/Hour Percentage of Energy Loss
2 2%
5 8%
10 30%
Source: Boiler Efficiency Institute
Key Factors for Maximum Efficiency
• Accurately sized equipment*
• Regular tune-up/service for maximum efficiency
• Operation range/turndown ratio*
• Excess air levels during entire operating range – combustion efficiency*
*Limitations which can only be overcome by a burner retrofit or
equipment change-out.
Linkage Controls vs. Linkageless Controls
One stepping motor for
air and fuel connected
via Linkages (Rods).
Differential is prone to
drift over time.
Linkage Controls vs. Linkageless Controls
• A linkageless control system
provides precise matching of
fuel and air via designated
stepping motors (no drifts.)
• The burner can be precisely
commissioned per the individual
boiler application.
• Result: Highest turndown and
lowest excess air.
Burner Retrofit Rational —
600 HP/20,085 Boiler
Efficiency
Gain = 10%
Payback = 4 years
$350,000
Purchase new
boiler/burner package
$200,000
Remove old boiler
$30,000
Install new boiler
$120,000
Burner Retrofit Rational —
600 HP/20,085 Boiler
• Net result of high efficient burner retrofit versus
boiler replacement:
• Capital cost reduced by $230,000
• Continuous fuel savings of 7%
• < 2 year payback
Retain existing boiler
$0
Retrofit w/ high efficient
burner: $ 60,000
$120,000 Efficiency gain = 7%
Payback = 2 years
Install burner
$60,000
In Summary
• Great Candidates for Burner Retrofits:
• Boiler/Burner installations with:
• High average excess air levels (> 5% excess air)
• High runtimes (Therms usage) (>3,500 hrs per year)
• Large load swings (turndown ratio < 6-1)
• Oversized equipment (potential of additional savings
by de-rating equipment)
Backup
Hospital Customer A
Retrofitted with high efficiency/high
turndown burner
Outcomes:
• Natural Gas Saves $29,770 annually
• $35,822 Ameren Illinois Incentive
• 1.5 Year Payback
Hospital Customer B
Weishaupt WM-GL30 Duel Fuel Burner
for use with new Hurst boiler
Integration with Building Automation
System
Outcomes:
• Saves 19,762 Therms annually
• $23,715 Ameren Illinois Incentive
Large Food Manufacturer
Existing register-style burners could
not produce the 65,000 pounds of
steam per hour they said they could
Retrofitted with high efficiency burners
that could produce 65,000 pounds of
steam per hour
Outcomes:
• Saves 342,206 Therms/Year with
Added Capacity
• $480,000 Ameren Illinois Incentive
• 2 Year Payback
Ameren Illinois Energy Efficiency Program Incentives:
28
• 12% customer bonus added to gas incentives
• Project must be submitted on or after Jan. 13, 2016 (no equipment/materials could have been purchased prior to Jan. 13)
• Project must be completed by May 31, 2016
• Potential gas-saving project ideas include:
• Steam traps
• Mechanical insulation
• Ozone laundry systems
• Commercial kitchen equipment
• HVAC controls
• Visit ActOnEnergy.com/GasBonus for details
Ameren Illinois Energy Efficiency
Program Energy Advisors
Call 1.866.800.0747
to request a consultation with an
Energy Advisor
1. Chad Whitehead Chad.Whitehead@gdsassociates.com 309.620.6333 2. Steven Smith Steven.L.Smith@leidos.com 309.212.5831 3. Rod Rhoads Rod.Rhoads@gdsassociates.com 217.649.8897 4. Mark Steinmetz Mark.Steinmetz@gdsassociates.com 217.670.9606 5. John Strode John.Strode@gdsassociates.com 309.370.0062 6. Fred Joshu Fred.M.Joshu@leidos.com 309.433.4316 7. Larry Erwin Lawrence.F.Erwin@leidos.com 309.838.2340
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