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The Benefits of Maintaining vs. Replacing Your Boiler
Neil Hill
Minneapolis Public Schools
Mpls. Public Schools
• 73 Sites
• Approximately 8.5 million square feet
• Currently 158 Active boilers
• Boilers range from 1915 to present
Boilers
• 109 Steam Boilers
• 22 Hot Water Boilers
• 27 Condensing boilers
• Burner inputs range from 399,000 to 23,500,000 BTU
Assets
Burner Upgrades
Burner Upgrade Results
• Higher efficiencies and reliability
• Rebate of $450 per MMBTU input; with a cap of 25% of
the equipment cost are available
Boiler Modifications
Boiler Modification Results
• Puts the heat in contact with the steel and is not
wasted on the brick.
• The boiler gains an increase in efficiency of 4-12%
• Custom rebates apply for qualifying and
preapproved projects
Do you have one of these?
Stack Damper Controls
Stack Damper Benefits
• Results in controlling excessive draft associated with
taller stacks.
• Along with Turbulator’s keeps more heat in the
boiler longer.
• Rebate of $250 MMBTU input with a cap of 35% of
the equipment cost
Turbulators
Turbulator Results
• Lower Stack Temperatures by holding the heat in
the boiler longer
• Increased boiler efficiencies of 3-5%
• Rebate up to 35% of the equipment cost with a cap
of $750/boiler
Condensing Boilers
• Currently have 27 condensing boilers on-line
• Range from 399,000 to 4 million BTU
• Duel Fuel- Savings of 14-16% of NG cost
• Rebate of up to $3,500 per MMBtu input when
greater than 88% efficiencies are achieved
Tune Ups
• Rebate of 25% of cost up to a cap of $300 per
boiler; This is eligible every other year
Steam Trap Program
• 58 sites with Steam Boilers- Over 6600 traps
• Initiated steam trap program in 2008
• Phase 2 starting in 2017
• Rebate of 35% of the repaired or replaced
equipment cost
Closing
• Efficiency gains are possible
• Rebates are available
The Benefits of Maintaining vs.
Replacing Your Boiler
Joe Mozeika Mulcahy Company
Boiler Maintenance & Repair!!
This should be your first line of defense when
trying to save your budget and your equipment.
There are several circumstances when
performing a “detailed” tune-up with minor repairs can save you thousands…
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Fouled tubes can appear as a major problem. Reality is, you need a good cleaning and burner tune up!!
Linkages are a major culprit of a fouled boiler
More than a dozen set screws and pivot points
Tube cleaning removes all the fuel Impurities that buildup over the
Course of a heating season 20
The effects of a fouled boiler that is needing
repair
efficiency loss per inch of soot
efficiency loss per inch of scale
3/32
1/32
1/16
1/8
5/32
7/32
3/16
1/4 60.8%
57.6%
53.8%
49.2%
43.7%
36.8%
27.9%
16.2%
34.3%
31.4%
28.2%
24.8%
20.7%
16.4%
11.6%
6%
Inch
es
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Rather than replace boiler, lets
enhance what we already !!
Your boiler is still in good structural condition, but some of the mechanical attributes are
starting to tire and are beyond a cost efficient repair.
Out with the old……. In with the new…….
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Opting to upgrade or modify your boiler
• Changing out the current burner for a new, linkage less burners
• Higher turndown rates with constant O2 levels • Separate your gas turndown from your oil
turndown • Add controls to your modifications. • O2 trim kits • Turbulators
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Linkageless Burners 1.Easily adapts to existing burner mountings. 2.Allows for finer tuning over entire combustion range. Can be anywhere from 7 to 18 points throughout modulation that can be tuned in vs. 3 points on a linkage burner. 3. Can adapt more technologically advanced controls to burner control. 4. Tighter tolerances yield better combustion process over entire heating season and reduce annual maintenance costs.
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Linkageless Burner Add-ons
1.BMS integration 2. O2 trim allowing the highest level of combustion efficiency 3. Independent curves for dual fuel burners 4. Variable Frequency Outputs
25
Turbulators
1.Increases flue gas turbulation, reducing laminar flow in tubes. 2.Easy to install, but does require burner to be re-tuned 3. Increases overall boiler efficiency.
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Outdoor Reset Controls!!
Allows for the water temperature to be
turned down when there is a light demand. Determines demand based on outdoor design
temperature vs design day temperature.
27
Adding just a few of these features
could have a rather dramatic
effect on fuel savings. Just
changing out the burner could
easily save 3-5% in energy
consumption. Reset controls,
turbulators, trim kits and other
accessories just add to the savings…
28
Protecting and enhancing the boiler that makes all the steam is one thing but what about those all important
steam traps????
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Basic Steam
• 1 lb. or 1 pint of water produces 1 lb. steam requiring 1170 BTU to vaporize
• 1 lb. of steam condenses to form 1 lb. condensate giving up 970 BTU
• 1,000 lb./hr. steam = 16.6 lb./minute • (1,000 lb./hr. 60 minutes)
• 16.6 lb./minute = 2 GPM • [16.6 lb./minute 8.3 (the weight of a gallon of water)]
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Trap Sizing Table
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How Much Can We Lose?
• Well, lets assume a 3/4” trap sized for 50,000 BTU’s an hour ( small load, but can show what just a small load can cost )
• That’s approximately 42.75 LBS per hour.
• Lets say that the trap is leaking because of a worn seat or stuck valve, what’s the harm with that??
• Well if even only 10% is leaking by, that is 5,000 BTU’s per hour!!!
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How Much Can We Lose?
• Ok, that wasn’t impressive enough so lets put it into dollars!!
• 5,000 BTU at .60 cents a therm ( 100,000 BTU’s )
• That’s 3 cents an hour, 36 cents a day, 1080 cents a month, 7560 cents a heating year!!!
• Or, $75.00 a heating season thrown away to mother nature!!
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Should I repair it? Well…. Yes you should!!!!
• Typical repair kit for a ¾” trap is less than $100.00.
• That is just a little over 1 heating season pay back.
• But don’t forget to turn in your rebate form to CenterPoint Energy for your 35% rebate. That brings your payback to just under a heating season!
• Very seldom does a trap need to be replaced, the iron doesn’t wear out, the components do!
• SO DO YOURSELF A FAVOR AND REPAIR YOUR TRAPS!!!
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