Second Saturdays: Cenergy HVAC

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Second Saturdays: Cenergy HVAC

  1. 1. Outside the Box Introduction to Quality Installation ofHigh Efficiency Heating and Cooling Systems
  2. 2. Overview Outside the Box – Introduction to QualityInstallation of High Efficiency HVAC Systems • Common Installation Issues Impacting Performance • Pressure Measurement and Diagnostics • Temperature Measurement and Diagnostics • Equipment vs. System Performance • Finding a Professional • Conclusion - Next Steps
  3. 3. Common Installation Issues Impacting Performance The House IS a System DUCT SYSTEM SHELL TIGHTNESS INSULATION CONTROLS VENTILATIONHEATING AND SYSTEM A/C COMBUSTION APPLIANCES © 2009 ESI, Inc.
  4. 4. Common Installation Issues Impacting PerformanceHVAC Efficiency - It’s All About the Installation1. Equipment Sizing / Selection – Manual J is the ANSI standard for sizing residential equipment2. Duct Design / Sizing – On average, duct systems are grossly undersized and restrict airflow significantly3. Duct Leakage – Delivering air to its destination is critical, but sealing ducts is often more complicated than it might appear4. Filter Type and Size – Improperly sized filters, or filter types other than what the designer assumed can wreak havoc on the system’s airflow © 2009 ESI, Inc.
  5. 5. Common Installation Issues Impacting PerformanceHVAC Efficiency - It’s All About the Installation5. Equipment Setup – Equipment today is complex and requires great attention to detail in its setup, configuration, and control system(s)6. Air Balancing – Ensuring the right amount of air is delivered to each room improves comfort and can help reduce utility costs7. Combustion Efficiency – Maximizing the delivered heat out of the fuel purchased requires more than what is included in a typical “swap the box” replacement8. Multi-Speed / Staged Equipment – Advanced technology means even more setup is required to operate properly © 2009 ESI, Inc.
  6. 6. Common Installation Issues Impacting Performance How Do Contractors Size Equipment? Survey Results (FSEC - 489 HVAC Contractors)– Software Represents Manufacturer’s Software– Other is primarily use of a “Short Form” or Utility Method
  7. 7. Common Installation Issues Impacting PerformanceCentral Iowa Sizing Results - Heating © 2009 ESI, Inc.
  8. 8. Common Installation Issues Impacting Performance Central Iowa Sizing Results - Cooling Cooling Sizing to Load - TOTAL Summary (100 Home Sample) 3500000 3000000 2500000 2000000 Design CoolingBtuh Manual J Max Size Installed (Output) 1500000 1000000 500000 0 © 2009 ESI, Inc.
  9. 9. Common Installation Issues Impacting Performance STATE OF THE INDUSTRYNine out of ten HVAC systems cannotoperate properly or efficiently without being repaired first. © 2009 ESI, Inc.
  10. 10. Common Installation Issues Impacting PerformanceCentral Iowa Results – Installed Efficiency Load © 2009 ESI, Inc.
  11. 11. Common Installation Issues Impacting PerformanceCentral Iowa Results – Installed Efficiency Load © 2009 ESI, Inc.
  12. 12. Common Installation Issues Impacting Performance The national average shows HVAC systems deliver only 57% of theequipment rated BTU into the building © 2009 ESI, Inc.
  13. 13. Common Installation Issues Impacting PerformanceGood news! After appropriate renovations, theaverage HVAC system can deliver over 90% of the equipment rated BTU into the building 6.2% System BTU Loss of equipment rated capacity 93.8% System BTU Delivery of equipment rated capacity SOURCE: NCI Certified Contractor Survey 11-05 to 2-06 © 2009 ESI, Inc.
  14. 14. Common Installation Issues Impacting Performance Less than 3% of service agreements include the duct system… SO WHO’S CHECKING IT? © 2009 ESI, Inc.
  15. 15. Common Installation Issues Impacting Performance How heavy is “standard” air?Training room Length x Width x HeightRoom cubic Feet x .075 pounds = theweight (in lbs) of the air in this room A typical fan has to move about 90pounds of air per minute. That’s 5400 pounds per hour. © 2009 ESI, Inc.
  16. 16. Common Installation Issues Impacting PerformanceSo, where do we start?Evaluate the System, not just the Box… Static Pressure – Helps us know if the system is delivering the right amount of air System Temperatures – Helps us understand the impact (gain / loss) of the duct system © 2009 ESI, Inc.
  17. 17. Pressure Measurement and Diagnostics Static Pressure is a lot like blood pressure. It’s the first, quick test of an HVAC system’s “circulation.”© 2009 ESI, Inc.
  18. 18. Pressure Measurement and DiagnosticsStatic Pressure is the amount ofresistance the fan must overcome tomove air throughout the system Pressure is measured using a manometerLike blood pressure,static pressure that istoo high or too low cancause problems!Fewer than 6% of contractors even check static pressure! © 2009 ESI, Inc.
  19. 19. Pressure Measurement and Diagnostics Supply +.19” + Return -.31” Equals .50”Add The most common static pressure rating for residential equipment is .50” of Total External Static Pressure © 2009 ESI, Inc.
  20. 20. Pressure Measurement and Diagnostics Total External Static Pressure Challenge.50” rated fan -.34” +.41”What is the system return static pressure? -.34” _______What is the system supply static pressure? _______+.41” .75”What is the system total external static pressure? _______What’s wrong with this system? Total Static Pressure too high – airflow will be low © 2009 ESI, Inc.
  21. 21. Pressure Measurement and Diagnostics© 2009 ESI, Inc.
  22. 22. Pressure Measurement and Diagnostics A pressure drop is the difference between two readings… We measure pressure drops to help troubleshoot airflow restrictions© 2009 ESI, Inc.
  23. 23. Pressure Measurement and Diagnostics Pressure drop is measured by subtracting the pressures on both side of a system component© 2009 ESI, Inc.
  24. 24. Pressure Measurement and Diagnostics Pressure Drops1. FILTERS – Dirty filters or incorrectly-sized filters will have a higher pressure drop2. COILS – Dirty coils, or newer higher-efficiency coils will have a higher pressure drop3. DAMPERS – Dampers that are not operating properly or are too restrictive will have a higher pressure drop4. ACCESSORIES – Basically, anything that is added into the air stream or is part of the duct system will have a pressure drop associated with it © 2009 ESI, Inc.
  25. 25. Pressure Measurement and DiagnosticsCoil Pressure Drops - Example © 2009 ESI, Inc.
  26. 26. Pressure Measurement and DiagnosticsFilter Pressure Drops - Example © 2009 ESI, Inc.
  27. 27. Pressure Measurement and Diagnostics Top 10 Static Pressure Repairs1. Filters are the number one cause of poor Indoor Air Quality in this country today. If the fan can’t move the air, the V in HVAC doesn’t occur.2. Clean cooling coils. Inspection alone does not verify the coil is clean. Measure coil pressure drop. Average 14 SEER coil drop = .32”3. The duct sizes typically used across the US are far too small. Adding an additional large return duct to relieve high static pressure. © 2009 ESI, Inc.
  28. 28. Pressure Measurement and Diagnostics Top 10 Static Pressure Repairs4. Poor duct installation is next. Straighten ducts, improve duct suspension, lengthen the radius of elbows, replace duct transition, the list goes on and on.5. Damaged ducting. Cable guys, phone repair techs and alarm system installers have little idea of their impact on duct system performance. © 2009 ESI, Inc.
  29. 29. Pressure Measurement and Diagnostics Top 10 Static Pressure Repairs6. Aging ducting. How long does flexible ducting last in a 140 degree attic?7. Duct systems designed for older, less efficient systems. In most areas of the country, ducts are significantly undersized.8. Inadequate fan capacity. With today’s coils and filter pressure drops, ask for a variable speed or higher static pressure rated fan. © 2009 ESI, Inc.
  30. 30. Pressure Measurement and Diagnostics Top 10 Static Pressure Repairs9. Outdated, rule-of-thumb duct design methods.10. Restrictive registers and grilles. Consider replacing with good quality commercial grilles. © 2009 ESI, Inc.
  31. 31. Temperature Measurement and Diagnostics Measuring Temperature Change ∆t = Delta t (The difference between two related temperatures)When measuring equipment ∆t is the difference between the temperature entering and exiting the equipment. When measuring system ∆t is the difference between thetemperature entering and exiting the system – or average return grille temperature minus average supply register temperature. © 2009 ESI, Inc.
  32. 32. Temperature Measurement and Diagnostics Equipment ∆t For CoolingEntering Temperature-Exiting TemperatureEquals Equipment ∆t For HeatingExiting 120°Entering - 70°Equipment ∆t 50° © 2009 ESI, Inc.
  33. 33. Temperature Measurement and Diagnostics System ∆t For Cooling Supply Register Temperature -Return Grille Temperature Equals System ∆t For Heating Return Grille 75° Supply Register - 115° System ∆t only 40° © 2009 ESI, Inc.
  34. 34. Temperature Measurement & Diagnostics Percent of System BTU Duct Loss or Gain Let’s take a look at system performance. This quick test and calculation offers a snapshot of system performance by taking only four temperature measurements and working a short formula. Gather the following four temperature measurements. 1. The temperature entering the equipment 2. The temperature exiting the equipment 3. A typical supply register air temperature 4. A typical return grille air temperature Page 119
  35. 35. Temperature Measurement & Diagnostics Percent of System BTU Duct Loss or Gain Next, subtract to find the equipment delta t, and subtract to find the system delta t. The divide as shown in the formula below. System Loss or Gain Formula Duct System Temperature Loss System Loss % = Equipment Temperature Change Page 119
  36. 36. Percent of System BTU Duct Loss or Gain Cooling Example:Temperature Diagnostics and Repairs Duct System Temperature Gain = 9° = 50% System Gain Equipment Temperature Change = 18° Heating Example: Duct System Temperature Loss = 15° = 25% System Loss Equipment Temperature Change = 60° Page 119
  37. 37. Duct Loss Example (Sensible BTUs) 72° 67°Temperature Measurement & Diagnostics Heating Mode Equipment ΔT 50° System ΔT 30° Return Duct Loss 5° Supply Duct Loss 15° What would the supply register temp be if there was no duct loss? 117° 102° 122º Page 120
  38. 38. Duct Loss Example (Sensible BTU)Temperature Measurement & Diagnostics Heating Mode – Use Data from Previous Drawing Return Grille Temp = 72° Supply Reg Temp = 102° Return Plenum Temp = 67° Supply Plenum Temp = 117° Return Duct Loss = 5° Supply Duct Loss = 15° Return Duct Loss + Supply Duct Loss = Total Duct Loss 5° + 15° = 20° Total Duct Loss / Equipment ΔT = % Duct Temp Loss 20° / 50° = 40% Page 121
  39. 39. Temperature Measurement & Diagnostics Duct Loss Challenge (Sensible BTU) 73° 69° Heating Mode Equipment ΔT 50 ° System ΔT 29 ° Return Duct Loss 4 ° Supply Duct Loss 17 ° What would the supply register temp be if there was no duct loss? 119° 102° ____ 123º Page 122
  40. 40. Duct Loss Example (Sensible BTU)Temperature Measurement & Diagnostics Heating Mode – Use Data from Previous Drawing Return Grille Temp = 73° Supply Reg Temp = 102° Return Plenum Temp = 69° Supply Plenum Temp = 119° Return Duct Loss = 4º Supply Duct Loss = 17° Return Duct Loss + Supply Duct Loss = Total Duct Loss 17° + 4° = 21° Total Duct Loss / Equipment ΔT = % Duct Temp Loss 21° / 50° = 42% Page 123
  41. 41. Temperature Measurement & Diagnostics Duct Loss Challenge (Sensible and Total BTU) 76° DB 70° DB 63.8° WB 62.4° WB Cooling Mode ΔT ΔH Equipment ° ____ System ° ____ Ret. Duct Loss ° ____ Sup. Duct Loss ° ____ 60° DB 66° DB 56.2° WB 58.1° WB Page 125
  42. 42. Temperature Measurement & Diagnostics Duct Loss Challenge (Sensible and Total BTU) 76° DB 70° DB 63.8° WB 62.4° WB Cooling Mode ΔT Equipment 16 ° System 4° Ret. Duct Loss 6° Sup. Duct Loss 6 ° 60° DB 66° DB 56.2° WB 58.1° WB Page 125
  43. 43. Duct Loss Example (Sensible BTU)Temperature Measurement & Diagnostics Cooling Mode – Use Data from Previous Drawing Return Grille Temp = 70° Supply Reg Temp = 66° Return Plenum Temp = 76° Supply Plenum Temp = 60° Return Duct Loss = 6º Supply Duct Loss = 6° Return Duct Loss + Supply Duct Loss = Total Duct Loss 6° + 6° = 12° Total Duct Loss / Equipment ΔT = % Duct Temp Loss 12° / 16° = 75% Page 126
  44. 44. Temperature Measurement and Diagnostics Duct Location• Inside Conditioned Space is Preferred• Attic/Crawl Space locations require significant duct insulation strategies• Sometimes ducts that seem like they are “inside” are really more connected to outside• Ducts in an unfinished basement often require duct insulation © 2009 ESI, Inc.
  45. 45. Temperature Measurement and Diagnostics Duct SealingLeaky Ductwork Costs U.S. Consumers an Average of $5,000,000,000 per Year – Leaky Ducts Can Cause Enormous Performance Penalties – Leaky Ducts Inside the Envelope are Important Too - Sometimes You Only Think They’re Inside – Comfort Can be Extremely Difficult to Achieve With Leaky Ducts – Leaky Returns Can Introduce Dirt, Dust, Insulation Fibers, etc Into the System © 2009 ESI, Inc.
  46. 46. Temperature Measurement and Diagnostics Duct SealingTypes of Sealants – Duct Mastic - Can be Used Easily on New Home Ducts or Accessible Existing Home Ducts – Aerosol Sealants - Seal Ducts from Inside Out – Foil Tape - Difficult to Install Properly, and Falls Off Over Time – Silicone - Expansion / Contraction Tends to Break Down Seals Over Time © 2009 ESI, Inc.
  47. 47. Temperature Measurement and Diagnostics Duct Sealing - DANGERSealing Ducts May Not Always Help Solve Problems… If the Ducts are Already Too Small, What Happens When You Seal Them?Before Sealing, You Need to Be Sure That the System Can Afford It! © 2009 ESI, Inc.
  48. 48. Temperature Measurement and Diagnostics System Temperature DefectsDEFECT REPAIRMore than 3 Add additional duct insulation ordegrees of thermal relocate ducts into conditionedloss through the spaceduct systemDuct airflow loss Repair or replace ducts. Tighten joints, seal ductsTemperature Seal joint between boot andchange at grille register to stop infiltration from unconditioned area. © 2009 ESI, Inc.
  49. 49. Temperature Measurement and Diagnostics System Temperature DefectsDEFECT REPAIRMore than 3° Repair duct system. Test,difference between adjust, and balance the HVACroom temperatures systemDamaged or Repair or replace equipmentinadequate equipment AND duct system. Do not justor accessories “swap boxes” © 2009 ESI, Inc.
  50. 50. Equipment Performance vs. System Performance Component vs. System TestingTraditional Service and Installation Practices Require Component-Level Testing Only• Component-Level Testing = “Perfect World” Testing *Perfect-World Testing Merely Makes a Statement About Potential Efficiency• System-Level Testing = “Real World” Testing *Real-Word Testing Measures the Actual, Installed Efficiency © 2009 ESI, Inc.
  51. 51. Equipment Performance vs. System Performance BENEFITS OF ADDRESSNG THE SYSTEM1. Equipment Change Only: BTU PER THERM 54,7202. Equipment & Renovation: BTU PER THERM 86,4003. Renovation Only: BTU PER THERM 72,000 © 2009 ESI, Inc.
  52. 52. Equipment Performance vs. System Performance GETTING THE BEST VALUEQuality Installation is critical to maximizing Installed Efficiency!Replacement with high efficiency equipment typically has little impact on utility consumption. In fact, sometimes customers have reported an increase in natural gas consumption.The primary reason for this is that newer furnaces require 50% more airflow than older furnaces and duct systems are typically significantly undersized. Without considering the entire system, the great new equipment may not even have a chance to work properly! © 2009 ESI, Inc.
  53. 53. Equipment Performance vs. System Performance The Tale of Two Systems 100k BTU Output Furnace Replacement Current Annual Heating Cost = $1353 (60% Installed Eff.)• Replace Unit Only w/ 95% AFUE • Replace Unit + Duct Renovation• Installed Eff. Decreased to 57% • Installed Eff. Increased to 89%• Reduced Heating Bill by $173/yr • Reduced Heating Bill by $597/yr• $5,000 Cost • $7,000 Cost• $1,500 Tax Credit • $1,500 Tax Credit• $450 Utility Incentive • $450 Utility Incentive• Total Investment = $3,050 • Total Investment = $5,050• Payback = 17.6 years • Payback = 8.5 years• Est. Equipment Life = 15 years • Est. Equipment Life = 15 years• ROI over Life of Equip. = $2,595 • ROI over Life of Equip. = $8,955• Residual Return After Payback = • Residual Return After Payback = ($455) $3,905 © 2009 ESI, Inc.
  54. 54. Conclusion - Next Steps Finding a Professional-ASK QUESTIONS! -How do you size equipment? -How will you design/re-design my duct system? -Do you check static pressure? -How will you maximize my SYSTEM’S efficiency?-Work with an Energy Rater with HVAC expertise-Focus your efforts “Outside the Box” as well-Accept that the House is a System © 2009 ESI, Inc.
  55. 55. Conclusion - Next StepsThank You for Attending Today’s Session! Questions?

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