Variable Speed Pumpingin Condensing BoilerSystemsGet the Savings you paid for!October 9, 2012
Presenters     Brian Hammarsten, CEM – Trade Relations      Manager at Xcel Energy     Peter Vinck – Senior Energy Effic...
Overview     Life Cycle Cost of Hot Water Systems     Demand Side System Opportunities     Transmission System Opportun...
Component Life Cycle Cost     Condensing Boiler          1 MMBTU boiler purchase = approx $20,000          Lifetime cos...
Traditional Boiler LCC ExamplePage 5
System LCC     System LCC* – Condensing Boiler, 2-way valve to heat           exchangers, vfd on pump            Total E...
Hot Water Systems     Demand          Space heating          Domestic water          Process     Transmission (Piping...
Demand Side Opportunity     Demand side opportunity investigation          Temp set points? In your process do you reall...
Outside air temp. vs supply water temp Temperature resets can be a great opportunity you might be missing during the highe...
Demand Side (cont.) – Domestic Hot Water heating in    off season     Boilers are left in operation to support domestic h...
Transmission Opportunity     Reducing Pumping Costs     Reduced System Flow BenefitsPage 11
Reducing Pumping Costs     If you have anything in this list, you may have          some opportunity to reduce cost.     ...
Reduced System Flow Benefits     Reduced transmission (pump) energy     Improved efficiency of condensing boiler     Re...
Supply Side Opportunity    Applying Condensing Boilers     Big Savings Potential           Unique ―green‖ investment opp...
Efficiency Levels of Gas-Fired Hot Water    BoilersPage 15
How Condensing Boilers get that    Efficiency “Boost”     Water Vapor Generated by Burning Natural Gas is          Conden...
Getting The “Rated” Efficiency Boost Out    of Condensing Boilers (>90% Efficiency)Page 17
Chart for Showing Moisture in Air Issues     Curve at Top Shows When ―Air‖          Can’t Hold Any More Moisture         ...
Applying Condensing Boilers vs Furnaces                       100%                       95%          Efficiency          ...
Applying Condensing Boilers vs Furnaces                       100%                       95%          Efficiency          ...
Applying Condensing Boilers vs Furnaces                       100%                       95%          Efficiency          ...
Three Rules for “Energy Value” of    Condensing Boiler System          1) Return Water Temperature!          2) Return Wat...
Getting Heat Into a Space in a Building:        Gas, Coal or Oil                         “Typical” Central System        3...
Central System Designed for Condensing Boiler          Gas at 3,500 F                                               Boiler...
Carrying Heat from One Place to Another     Heat Carried by Water or Air           Depends on temperature change (TD or ...
System Piping: Driving Return Water    Temperature Down              Boiler Efficiency                                  Ty...
System & Load Affects on Condensing    Boiler Efficiency “Boost”     Lower Flow (e.g. Pump VSD & 2-way Valves)          ...
Outdoor Reset Lowers Water Temperature          As the heating load goes down, less temperature difference is needed to dr...
Combined Outdoor Reset & VSDPage 29
Getting The “Rated” Efficiency Boost Out    of Condensing Boilers (>90% Efficiency)Page 30
Service Hot Water: Driving Return Water    Temperature Down     Traditional Coil-In Tank Requires High Boiler          Te...
Key Design & Application Considerations:    Preventing Problems     Product-Specific Issues           Small water passag...
Key Design & Application Considerations:    Preventing Problems (cont.)     Venting Considerations           Design & In...
Key for Condensing Boiler Efficiency:    Driving Return Water Temperature Down     Space Heating Elements     System Pip...
In Conclusion....     Condensing Boilers Can Be a Great, Green Investment     Success Depends on Different Approach by A...
Utility “Key”     Utilities offer rebates to customers to help pay for the          identification, energy savings quanti...
Questions?Page 37
Bonus Slides     The following slides are bonus material that was          cut from the final, live presentation due to t...
Condensing Boiler Sensitivity to Excess Air     Controlling Excess Air Even More Important           Excess air reduces ...
Traditional Factor of Burner “Excess Air”    Is Even More CriticalPage 40
Condensing Boiler Comparison to Direct-    Fired Heater                                        Direct-Fired HeaterPage 41
Chart for Showing Moisture in Air Issues     Moisture is Much More Diluted      in Direct-Fired Heater     It Reaches a ...
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Variable Speed Pumping in Condensing Boiler Systems

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  • Slide #27: Using outdoor reset could result in a higher return water temperature. With two-way valves and no bypass then with given coil load the higher the entering water temperature the colder the leaving water temperature. Verify with a coil program or using the log mean square difference.
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Variable Speed Pumping in Condensing Boiler Systems

  1. 1. Variable Speed Pumpingin Condensing BoilerSystemsGet the Savings you paid for!October 9, 2012
  2. 2. Presenters  Brian Hammarsten, CEM – Trade Relations Manager at Xcel Energy  Peter Vinck – Senior Energy Efficiency Engineer at Xcel Energy  Russ Landry PE, LEED® AP - Senior Mechanical Engineer at the Center for Energy and EnvironmentPage 2
  3. 3. Overview  Life Cycle Cost of Hot Water Systems  Demand Side System Opportunities  Transmission System Opportunities  Supply Side System Opportunities  Next StepsPage 3
  4. 4. Component Life Cycle Cost  Condensing Boiler  1 MMBTU boiler purchase = approx $20,000  Lifetime cost for the gas to operate boiler = $112,800  Of the total cost of ownership, only 17% goes to the purchase price of that boiler  Circulator Pump  5 hp pump costs = approx $2,000  Lifetime cost for the energy to operate pump = $26,750  Of the total cost of ownership, only 7.5% goes to the purchase price of the pumpPage 4
  5. 5. Traditional Boiler LCC ExamplePage 5
  6. 6. System LCC  System LCC* – Condensing Boiler, 2-way valve to heat exchangers, vfd on pump  Total Equipment = $53,000  1 MMBTU condensing boiler purchase = $20,000  Valves & Piping modifications = $8,000  Pump and Drive package = $5,000  Labor and misc materials = $20,000  Total Energy Costs = $202,650  Lifetime cost for gas= $112,800  Lifetime cost for pump = $26,750  Lifetime cost for fans = $63,100  Of the total cost of ownership, only 15% to 30% goes to the purchase price of the initial equipment purchase * This is a theoretical examplePage 6
  7. 7. Hot Water Systems  Demand  Space heating  Domestic water  Process  Transmission (Piping, Pumps & Valves)  Pumps  Piping  Coils  Supply Side  Condensing boiler  Combustion air fan  Feed water pump  ControlsPage 7
  8. 8. Demand Side Opportunity  Demand side opportunity investigation  Temp set points? In your process do you really need 190 degree water or will 175 work?  Outside air temperature supply water reset temperature  Domestic Hot Water heating in off seasonPage 8
  9. 9. Outside air temp. vs supply water temp Temperature resets can be a great opportunity you might be missing during the higher outside air temperatures. Giving you lower losses due to over heating as well as lower return water helping a condensing boiler.Page 9
  10. 10. Demand Side (cont.) – Domestic Hot Water heating in off season  Boilers are left in operation to support domestic hot water heat during summer.  Consider separating the systems in order to increase efficiency of domestic hot water year round.  This would save on equipment life, energy costs, redundancy, etc.Page 10
  11. 11. Transmission Opportunity  Reducing Pumping Costs  Reduced System Flow BenefitsPage 11
  12. 12. Reducing Pumping Costs  If you have anything in this list, you may have some opportunity to reduce cost.  Throttle valve-control system  Bypass (recirculation) line normally open  Multiple parallel pump system with same number of pumps always operating  Constant Pump operation in a batch environment or frequent cycle batch operation in a continuous process  Cavitations noise (at pump or elsewhere in the system)  High system maintenance  Systems that have undergone change in functionPage 12
  13. 13. Reduced System Flow Benefits  Reduced transmission (pump) energy  Improved efficiency of condensing boiler  Reduced maintenance costPage 13
  14. 14. Supply Side Opportunity Applying Condensing Boilers  Big Savings Potential  Unique ―green‖ investment opportunity when replacing boiler or building new building  >15% ROI for some projects  But… Savings Depend Heavily on Operating Conditions  New construction optimal design very different from typical boiler system  Retrofit situations must be carefully evaluatedPage 14
  15. 15. Efficiency Levels of Gas-Fired Hot Water BoilersPage 15
  16. 16. How Condensing Boilers get that Efficiency “Boost”  Water Vapor Generated by Burning Natural Gas is Condensed  Water vapor is natural product of burning natural gas  About 12% of flue gas is water vapor, but….  Condensing Energy ≈ 2,000 F of Vapor Temperature Drop  Condensation Only Occurs at Low Water Temperatures  Flue gas dewpoint ~130 F  Efficiency keeps improving as temperature dropsPage 16
  17. 17. Getting The “Rated” Efficiency Boost Out of Condensing Boilers (>90% Efficiency)Page 17
  18. 18. Chart for Showing Moisture in Air Issues  Curve at Top Shows When ―Air‖ Can’t Hold Any More Moisture (aka dewpoint or saturated)  Once at the Top, Cooling More Condenses Moisture Out of AirPage 18
  19. 19. Applying Condensing Boilers vs Furnaces 100% 95% Efficiency 90% 85% 80% 75% 60°F 80°F 100°F 120°F 140°F 160°F 180°F 200°FPage 19 Entering Water/Air Temperature
  20. 20. Applying Condensing Boilers vs Furnaces 100% 95% Efficiency 90% 85% 80% 75% 60°F 110°F 160°FPage 20 Entering Water/Air Temperature
  21. 21. Applying Condensing Boilers vs Furnaces 100% 95% Efficiency 90% 85% 80% 75% 60°F 80°F 100°F 120°F 140°F 160°F 180°F 200°FPage 21 Entering Water/Air Temperature
  22. 22. Three Rules for “Energy Value” of Condensing Boiler System 1) Return Water Temperature! 2) Return Water Temperature! 3) Return Water Temperature!Page 22
  23. 23. Getting Heat Into a Space in a Building: Gas, Coal or Oil “Typical” Central System 3,500 – 4,000 F Boiler ~350 to Avg Boiler Water 170 F 400 F180°F160°F Air Handler/VAV Radiators140°F120°F100°F Mix 80°F 60°F 40°F Mixed or Cooled Air 20°F 0°F-20°FPage 23Page 23
  24. 24. Central System Designed for Condensing Boiler Gas at 3,500 F Boiler180°F Boiler Water 160 F Average +160°F Air Handler/VAV Radiant140°F Radiators Floor120°F Heated Air100°F Mix 80°F 60°F 40°F Mixed or Cooled Air 20°F 0°F-20°FPage 24
  25. 25. Carrying Heat from One Place to Another  Heat Carried by Water or Air  Depends on temperature change (TD or T)  Depends on water or air flow ratePage 25
  26. 26. System Piping: Driving Return Water Temperature Down Boiler Efficiency Typical Flow Low Flow 100%  Avoid 3-way/4-way Valves on Main Line  Reduced Flow Brings Down Return Temperature 95% iciencyPage 26  If Mixed Boilers – Cold Water & Max Load to Condensing 90%
  27. 27. System & Load Affects on Condensing Boiler Efficiency “Boost”  Lower Flow (e.g. Pump VSD & 2-way Valves)  Pump Energy Savings  Low Return Water Temperature = Condensing Boiler Efficiency Improvement  If low delta, may be good opportunity in any system  Outdoor Reset Control  Reduces Load from Overheating & Pipe Heat Loss  Lower Return Water Temperature = Condensing Boiler Efficiency Improvement  If high temperatures in mild weather, may be good opportunity in any systemPage 27
  28. 28. Outdoor Reset Lowers Water Temperature As the heating load goes down, less temperature difference is needed to drive the heat flow.180°F160°F Boiler Water 150 F Average140°F120°F100°F 80°FSpace 75 F 60°F 40°F 20°F 0°F-20°FPage 28
  29. 29. Combined Outdoor Reset & VSDPage 29
  30. 30. Getting The “Rated” Efficiency Boost Out of Condensing Boilers (>90% Efficiency)Page 30
  31. 31. Service Hot Water: Driving Return Water Temperature Down  Traditional Coil-In Tank Requires High Boiler Temperatures  Efficiency > Traditional Water Heaters  Efficiency Sacrificed with Condensing Equipment >130 F 130 F BoilerPage 31
  32. 32. Key Design & Application Considerations: Preventing Problems  Product-Specific Issues  Small water passages in old cast iron system  Pressure drop compatibility with system  Flow rate compatibility (short-cycling)  Control coordination  Dual temperature inlets  General Load & System Issues  Ability to provide adequate heat w/low return temperatures  Ability to reduce flow rate w/out branch balance problems  2-way valves on loads to replace 3-way valvesPage 32
  33. 33. Key Design & Application Considerations: Preventing Problems (cont.)  Venting Considerations  Design & Installation Details to Deal with Condensate  Sidewall Venting Can Cause Moisture Problems With Large Boilers  Orphaned Water Heater  Vent Cost Key Factor @Bottom of Hi-RisePage 33
  34. 34. Key for Condensing Boiler Efficiency: Driving Return Water Temperature Down  Space Heating Elements  System Piping  System Control—Pump  System Control—Temperature  Service Hot Water 100% 95% Boiler Efficiency 90% 85% 80% 75% 80°F 100°F 120°F 140°F 160°F 180°F Entering Water TemperaturePage 34
  35. 35. In Conclusion....  Condensing Boilers Can Be a Great, Green Investment  Success Depends on Different Approach by All  Minimize return water temperature!  Minimize return water temperature!  Minimize return water temperature!  High Efficiency Boiler Information  Air-Conditioning, Heating, and Refrigeration Institute (www.ahrinet.org)  EnergyStar.gov  California Energy Commission web site  Consortium for Energy Efficiency www.cee1.org/gas/gs-blrs/gs-blrs-main.php3 www.cee1.org/gas/gs-blrs/Boiler_assess.pdfPage 35
  36. 36. Utility “Key”  Utilities offer rebates to customers to help pay for the identification, energy savings quantification, and for the changes once implemented.  Check with your electric and gas utility to see what rebates the offer  There are several here today  Programs to look for:  Study (investigation process) – Heating System Optimization, C/I Turn Key, Audits  Tune ups – Boiler Tune ups, Steam Trap Leak Study, Recommissioning  Prescriptive Measures – O2, Stack Dampers, pipe insulation, new boilers, VFDs, Motors  Custom – Insulation of valves, rebates for industrial process heating systems, most demand side measures, piping modifications, adjust temp set points.Page 36
  37. 37. Questions?Page 37
  38. 38. Bonus Slides  The following slides are bonus material that was cut from the final, live presentation due to time constraints.Page 38
  39. 39. Condensing Boiler Sensitivity to Excess Air  Controlling Excess Air Even More Important  Excess air reduces concentration of water vapor  Dewpoint decreasesPage 39
  40. 40. Traditional Factor of Burner “Excess Air” Is Even More CriticalPage 40
  41. 41. Condensing Boiler Comparison to Direct- Fired Heater Direct-Fired HeaterPage 41
  42. 42. Chart for Showing Moisture in Air Issues  Moisture is Much More Diluted in Direct-Fired Heater  It Reaches a Lower Temperature, but Never Condenses (THANKFULLY!) Direct Fired HeaterPage 42

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