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Weather Normalization Presented by John Avina Abraxas Energy Consulting

Weather Normalization Presented by John Avina Abraxas Energy Consulting. Why How Reading Bills to Understand Building Humidity Benchmarking with Normalization. OUTLINE. Retail in Wisconsin. Retail in Wisconsin. Average Weather….

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Weather Normalization Presented by John Avina Abraxas Energy Consulting

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  1. Weather Normalization Presented by John Avina Abraxas Energy Consulting

  2. Why How Reading Bills to Understand Building Humidity Benchmarking with Normalization OUTLINE

  3. Retail in Wisconsin

  4. Retail in Wisconsin

  5. Average Weather…. • Average of all the high and low temperatures during the billing period

  6. Retail in Wisconsin

  7. Retail in Wisconsin

  8. Retail in Wisconsin

  9. Retail in Wisconsin

  10. Retail in Wisconsin

  11. Retail in Florida

  12. Retail in Florida

  13. Retail in Florida

  14. Retail in Florida Cooling Balance Point = 60

  15. Retail in Florida Cooling Balance Point = 67

  16. Retail in Minnesota

  17. Retail in Minnesota

  18. College in Boston

  19. College in Boston

  20. Retail in San Francisco

  21. Recap: Why Use Weather?

  22. International Performance Measurement and Verification Protocol M and V Standards www.ipmvp.org

  23. Federal Energy Management Guidelines M and V Standards http://www.eere.energy.gov/femp/pdfs/26265_seci.pdf

  24. ASHRAE Guideline 14 M and V Standards http://www.ashrae.org

  25. 4 Methods of M & V Option A - Partially Measured Retrofit Isolation Option B - Retrofit Isolation Option C - Whole (or Part) Building (Utility Bills) Option D – Calibrated Simulation Methods chosen based upon budget, need for accuracy, ECMs installed, Metering Setup IPMVP M&V Options

  26. Option A - Partially Measured Retrofit Isolation Partial short-term/continuous measurements – some but not all stipulated For Separable ECM Savings Determination - Lighting IPMVP M&V Options

  27. Option B - Retrofit Isolation Full short-term or continuous field measurement - no stipulations For Separable ECM Savings Determination - HVAC subsystem IPMVP M&V Options

  28. Option C - Whole (or Part) Building Full continuous energy use and demand measurement during Baseline and Post- Retrofit Periods Collective Savings of all ECMs for Area monitored by a Single Meter IPMVP M&V Options

  29. Option D – Calibrated Simulation Computer-based simulation of energy use of building components Simulation Calibration, Considerable skills, Costly ???? IPMVP M&V Options

  30. Supposean ESCO choosesOption C, UtilityBill Analysis... Whywouldan ESCO wanttocorrectforweather WhyNotkeepit simple and just compare pre and post retrofitbills Billions of Dollars of savings are trackedusingOption C M&V and Utility Bill Analysis

  31. Why Utility Bills Don’t Always Yield Savings? Suppose an ESCO expected this from a Chiller Retrofit…. Savings

  32. Why Utility Bills Don’t Always Yield Savings? …and instead got this…. Increase

  33. Seen Him Before? Why Aren’t There Any Savings? What Do We Tell the Customer? Will I Keep My Job? Will I Get My Bonus?

  34. The ESCOs’ Dilemma How Can They Show Savings This Year?

  35. The ESCOs’ Dilemma How Can They Show Savings This Year? Real Data Cooling kWh ~ CDD Which means… double CDD  double Cooling kWh

  36. Retail in Minnesota

  37. How to Perform Weather Normalization Start with Bills and Weather Data

  38. Determine How Bills Vary with Weather Using Weather toUnderstand Bills Electric used to Cool Only Electric used to Heat & Cool

  39. Estimate Balance Point Temperature Sensitive Usage Non-Temperature Sensitive Usage Balance Point Cooling Balance Point is the Temperature at which the Building Starts to Cool. Low Cooling Balance Points indicate Outside Air is NOT being used for Free Cooling.

  40. Estimate Balance Point Temperature Sensitive Usage Non-Temperature Sensitive Usage Balance Point Balance Point is the Temperature at which the Building Starts to Heat.

  41. Calculate Cooling Degree Days • For each day in Billing period… • CDDi=(Ave Outside Temp - Bal Point Temp) X 1day + • Where Ave Outside Temp is the average between high and low temperature for the day. • And Bal Point Temp (balance point temperature) is the balance point found in the previous slide. • You cannot have negative CDDs • 2. CDDBilling Period = S(CDDi)

  42. Calculate Heating Degree Days • For each day in Billing period… • HDDi=(Bal Point Temp - Ave Outside Temp) X 1day + • Where Ave Outside Temp is the average between high and low temperature for the day. • And Bal Point Temp (balance point temperature) is the balance point found in the previous slide. • You cannot have negative HDDs • 2. HDDBilling Period = S(HDDi)

  43. Weather Normalization Perform a Linear Regression between Energy Usage and CDD (and/or) HDD. Find the best fit line. This is the Cooling Balance Point. Cooling Balance Point is the temperature at which the building starts cooling.

  44. Normalization Tools You can use Excel or Canned Software There are Several Desktop applications that handle weather Normalization, one of which specializes in it.

  45. Understanding the Baseline Your Fit Line Has an Equation, which is called the Baseline Equation y = mx + b which could be rephrased into something like this kWh = 61.986 x #CDD + 1872.7 x # days

  46. Energy Balance Use the Regression Coefficients to True Up Energy Balance

  47. Understanding the Baseline Your Fit Line Has an Equation, which is called the Baseline Equation Baseline Equation = Best Fit Line ~ Base Year Bills So now we can work with the Baseline Equation and throw out the bills. We don’t need them any more. Baseline Equation represents your energy usage patterns during your Base Year

  48. Understanding the Baseline What Good is the Equation? We take a Current Year Bill, determine # of days in the bill, determine # of CDD (or HDD) and plug those into the Baseline Equation. 7/21/05Bill 100,000 kWh 700 CDD 30 days Baseline kWh = 61.986 x #CDD + 2872.7 x # days Baseline kWh = (61.986 x 700) + (2872.7 x 30) Baseline kWh = 129,571 kWh

  49. Understanding the Baseline What Good is the Equation? So Baseline kWh represents how much energy your facility would have used this year given current weather conditions and Base Year usage patterns. The Baseline Equation represents Base Year Usage patterns, and we applied Current Year weather to it 7/21/05Bill 100,000 kWh 700 CDD 30 days Baseline kWh = 61.986 x #CDD + 2872.7 x # days Baseline kWh = (61.986 x 700) + (2872.7 x 30) Baseline kWh = 129,571 kWh

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