Technical overview of the research questions and findings as well as a discussion of targeted recommendations for utility energy efficiency programs and operator learning.

1. COMMERCIAL CONDENSING
BOILER OPTIMIZATION
Russ Landry, PE, LEED®AP
Senior Mechanical Engineer

2. Welcome
Conservation Applied Research & Development (CARD)
Webinar
Mary Sue Lobenstein, R&D Program Administrator
Marysue.Lobenstein@state.mn.us

3. Minnesota Applied Research &
Development Fund
Purpose to help Minnesota utilities achieve 1.5
% energy savings goal by:
• Identifying new technologies or strategies to
maximize energy savings;
• Improving effectiveness of energy conservation
programs;
• Documenting CO2 reductions from energy
conservation programs.
Minnesota Statutes §216B.241, Subd. 1e.

4. CARD RFP Spending by Sector
thru mid-FY2017
• 8 Funding Cycles
• Nearly 380 proposals
• 92 projects funded
Multi-sector
(21) 25.3%
Commercial (36)
37.6%
Residential
1-4 unit (15)
18.7%
Industrial (10)
8.6%
Multifamily 5+
unit (4) 6.6%
Agricultural (6)
3.1%

5. Pg. 5
Research
Financing Policy
Programs
Discover + Deploy
the most effective solutions for a healthy, low-carbon economy
Planning &
Consulting

6. Pg. 6
Commercial Condensing Boiler
Optimization
PRESENTER
Russ Landry, P.E. LEED® AP
Senior Mechanical Engineer
Center for Energy & Environment

7. Pg. 7
How Conventional Boilers Function

8. Pg. 8
• Conventional boilers
• All steam goes out the vent
• Safety factor to prevent condensation limits efficiency
How Condensing Boilers Outperform
Conventional Boilers

9. Pg. 9
How Condensing Boilers Outperform
Conventional Boilers

10. Pg. 10
• Conventional boilers
• All steam goes out the vent
• Safety factor to prevent condensation limits efficiency
• Condensing boilers
• A portion of the steam is used for heating
• No safety factor
How Condensing Boilers Outperform
Conventional Boilers

11. Pg. 11
Condensing Efficiency “Boost”
1 pound of captured steam heats 50 pounds of water
11
=
20°F
Rise

12. Pg. 12
Condensing Boiler Efficiency Improvement
80% 85% 90% 95% 100%
Condensing--Your Building
Condensing--Ideal
Condensing--Minimum
Conventional Boiler
Conventional
Condensing
?????
If condensate drain dry

13. Pg. 13
3 Rules for...
“Energy Value” of Condensing Boiler System
1) Low Return Water Temperature!
2) Low Return Water Temperature!
3) Low Return Water Temperature!

14. Pg. 14
Condensing Boiler Efficiency Dependence
on Operating Conditions

15. Pg. 15
Boiler System Temperatures in Real
Buildings & Impact on Efficiency
-20°F
0°F
20°F
40°F
60°F
80°F
100°F
120°F
140°F
160°F
180°F
Boiler Entering Water Temperature Outdoor Temperature
Condensation
Threshold

16. Pg. 16
Flow Impact on Boiler Efficiency Via
Entering Water Temperature
Typical Flow

17. Pg. 17
Flow Impact on Boiler Efficiency Via
Entering Water Temperature
Typical Flow
Low Flow

18. Pg. 18
Traditional Burner Tuning: Excess Air Up
Chimney & Reduced Condensing
86%
88%
90%
92%
94%
96%
98%
80°F 90°F 100°F 110°F 120°F 130°F 140°F
BoilerEfficiency
Boiler Return Water Temperature
20% Excess Air (3.8% O2)

19. Pg. 19
Traditional Burner Tuning: Excess Air Up
Chimney & Reduced Condensing
86%
88%
90%
92%
94%
96%
98%
80°F 90°F 100°F 110°F 120°F 130°F 140°F
BoilerEfficiency
Boiler Return Water Temperature
20% Excess Air (3.8% O2) 30% Excess Air (5.3% O2)

20. Pg. 20
Traditional Burner Tuning: Excess Air Up
Chimney & Reduced Condensing
86%
88%
90%
92%
94%
96%
98%
80°F 90°F 100°F 110°F 120°F 130°F 140°F
BoilerEfficiency
Boiler Return Water Temperature
20% Excess Air (3.8% O2) 30% Excess Air (5.3% O2) 40% Excess Air (6.5% O2)

21. Pg. 21
Project Overview: Condensing Boiler
Optimization
• Preliminary Market Study & Site Selection
• Monitoring & Analysis of 12 Buildings
• 4 Education
• 4 Multifamily
• 4 Government/Office
• Industry Survey
• Dissemination

22. Pg. 22
Minnesota’s Condensing Boiler Market
Study Findings
• Market Dominance of Condensing Boilers
• Condensing boilers have become the default choice
• Used in all building types that have space heating boilers
• Efficiency Concerns Noted
• Manufacturer’s reps acknowledge often suboptimal situations
• Part-load efficiency improvements may be significantly
overstated in some cases per tuning recommendations

23. Pg. 23
Project Overview: Condensing Boiler
Optimization
• Preliminary Market Study & Site Selection
• Monitoring & Analysis of 12 Buildings
• 4 Education
• 4 Multifamily
• 4 Government/Office
• Industry Survey
• Dissemination

24. Pg. 24
Estimated Annual Efficiency Based on
Monitored Conditions
80% 85% 90% 95% 100%
ED1
ED2
ED3
ED4
GO1
GO2
GO3
MF1
MF2
MF3
MF4
Hybrid Operating
Efficiency
Condensing Operating
Efficiency
Condensing Rated
Efficiency

25. Pg. 25
Potential Efficiency with Proposed
Features
80% 85% 90% 95% 100%
ED1
ED2
ED3
ED4
GO1
GO2
GO3
MF1
MF2
MF3
MF4
Plant Operating
Efficinecy
Potential with Measures
Condensing Rated
Efficiency

26. Pg. 26
Potential Savings by Design Feature
Measure Type # of Sites
Average of
Sites with
Measure
Average
Across
All Sites
Reset Control 10 1.54% 1.40%
Burner Tune Up 10 0.80% 0.72%
Staging Control 8 1.15% 0.83%
Variable Speed
Pumping
10 0.48% 0.44%
Piping Change 5 2.06% 0.94%
Total 11 3.97%

27. Pg. 27
Cost-Effective Retrofits After
Installation Completed
Site
Outdoor
Reset
Burner
Tune-Up
Staging
Control
Variable
Speed
Pumping Piping
Package
Cost
Package
Savings
(Therms)
Payback
(Years)
ED1 X X X O X $8,800 4,437 2.8
ED2 X X O $1,600 789 2.9
ED3 X X X O $3,100 2,822 1.6
ED4 X X X O $2,600 768 4.8
GO1 X X X $13,500 4,379 4.4
GO2 X X $2,750 5,248 0.7
GO3 X O O O $250 229 1.6
MF1 X X O O $3,400 1,217 4.0
MF2 O O O O NA NA
MF3 X X O O $620 376 2.4
MF4 X X X O $800 420 2.7
Sum 10 8 5 2 1 $37,420 20,686 2.6
X = Included; O = Excluded; Blank = No Opportunity

28. Pg. 28
Project Overview: Condensing Boiler
Optimization
• Preliminary Market Study & Site Selection
• Monitoring & Analysis of 12 Buildings
• 4 Education
• 4 Multifamily
• 4 Government/Office
• Industry Survey
• Dissemination

29. Pg. 29
Survey Findings:
Primary Boiler Control System
On Board Controls
BAS Tie-In
Separate Dedicated Controls
0%
10%
20%
30%
40%
50%
Rarely
Sometimes
Often
Almost
Always

30. Pg. 30
Survey: Most Commonly Witnessed
Issues Impacting Efficiency
Issue Percent
Turning off and on frequently (short cycling) 67%
Difficulties coordinating control between a BAS and
the boiler(s) 61%
Piping arrangements circulate water through an
idle, non-condensing boiler 44%
Boiler minimum temperature limited by the need to
heat service hot water 44%
Outdoor reset control does not lower temperature
as much as it could in mild weather 39%

31. Pg. 31
Survey: What Would be Most Worthwhile to
the Owner for Future Installations
Potential Program Element Percent
a. Piping Design Review 11%
b. Control Sequence Review 11%
c. Site-Specific Savings Estimate 6%
d. Bonus Rebate for Quality Design 11%
e. Bonus Rebates for Individual Design Features 6%
f. Commissioning of Installation and Controls 44%
g. New Training Options for Designers & Installers 11%

32. Pg. 32
Survey: What Would be Most Worthwhile to
the Owner for Previous Installations
Potential Program Element Percent
a. Specialized Engineering Review 11%
b. Gas Rebate for Variable Speed Drive 6%
c. Rebates for Control Upgrades 6%
d. Rebates for Optimizing Control Settings 17%
e. Resources on Optimal Control & Operation 11%
f. Site-Specific Guide for Controls 6%
g. New Training Options for Operators 44%

33. Pg. 33
Project Overview: Condensing Boiler
Optimization
• Preliminary Market Study & Site Selection
• Monitoring & Analysis of 12 Buildings
• 4 Education
• 4 Multifamily
• 4 Government/Office
• Industry Survey
• Dissemination

34. Pg. 34
Dissemination of Project Findings
• Presentations:
• 2014 CenterPoint Energy Technology Conference
• 2015 AEE/ASHRAE Twin Cities Energy Expo
• 2016 Minnesota Blue Flame Gas Association’s Natural Gas
Conservation Conference
• Today’s webinar
• Detailed final report--available now

35. Pg. 35
CIP Program Potential to Go Farther
Finding CIP Implications
#1
Additional Savings Potential
-- > Savings possible with control, piping, pumping and
burner tuning optimization
--Hybrid systems have greatest additional savings/site
--New program features can achieve more savings @ time of
installation or afterwards
--Hybrid systems could be targeted for maximum impact
#2
Cost Effectiveness of Changes
--~3/4 of additional savings ≤ 5 year payback
--Control & burner tuning most common & cost-
effective
--Most identified additional savings can be achieved cost-
effectively
--Initiatives focused entirely on burner tuning and boiler
system controls can reap most of this additional savings
#3
Perceived Value of Possible CIP Program Features
--Local contacts consider numerous possible program
features worthwhile
--Commissioning, training, and support for changing of
control settings are at the top of the list
--Additional program features are likely to be well-received,
even if they add some complication
--Top consideration for additional program featuers should
be given to commissioning, training, and optimized control
adjustment

36. Pg. 36
Current CIP Program Impacts
Finding CIP Implications
#4
Market Penetration
--Condensing boilers dominate the commercial boiler
market across all building types and sizes.
--High free ridership should be considered in program
impact evaluation.
#5
In Field Efficiency
--Condensing boilers operate much more efficiently
than conventional boilers, but far below their
nominal rated efficiencies
--Program impact and cost-effectiveness should be based on
conservative savings estimates.
#6
Tune-Up Savings Magnitude
--Condensing boilers should be more sensitive to tune-
up than conventional boilers
--Potential savings was still far below current CIP
program assumed savings for tune-ups of
conventional boilers.
--A fresh evaluation of the savings achieved through boiler
tune-up programs may be needed;
1) to reflect the current boiler & burner stock; and
2) to review the savings that can be achieved for various
types of common boilers and burner.

37. Pg. 37
Resources
• Commercial Condensing Boiler project page
https://www.mncee.org/resources/projects/condensing-boiler-
optimization/
• Final Report
http://bit.ly/2pzgO3d

38. Pg. 38
Audience
Question & Answer

39. CARD Webinar
Thanks for Participating
Upcoming Webinars:
• May 18 – Duct Leakage in Large C&I Buildings
• May 24 – T12 Lighting Saturation Study
• June 14 – Reducing Envelope Leakage in MF Buildings Using Aerosol Sealant
• June 22 – Improving Effectiveness of Commercial Energy Recovery Ventilation
If you have questions or feedback on the CARD program contact:
Mary Sue Lobenstein
marysue.lobenstein@state.mn.us
651-539-1872

40. Pg. 40

41. Pg. 41

42. Pg. 42

43. Russ Landry, P.E.
rlandry@mncee.org
Mary Sue Lobenstein
MarySue.Lobenstein@state.mn.us