Comments on DOE Commercial Building Asset Rating Program

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The DOE has decided to pilot and implement a commercial building Asset Rating system that will evaluate and score the physical characteristics that define the energy efficiency of commercial …

The DOE has decided to pilot and implement a commercial building Asset Rating system that will evaluate and score the physical characteristics that define the energy efficiency of commercial buildings. This new DOE “AR” will be in addition the EPA’s ENERGY STAR program which scores the actual energy consumption of commercial buildings.

The DOE is asking for feedback from interested parties.

Here are the key issues that I have commented on:
• Can buildings that are performing poorly (with low ENERGY STAR scores) publicize a good Asset Rating score and hide their poor performance? Or should buildings claiming high Asset Ratings be required to disclose how they are actually performing?
• Should the new AR system use the ENERGY STAR scoring system (0 to 100) or a different one?
• What building attributes should be on the input worksheet and how should they be weighted in the final score?

If the right building attributes are selected by the DOE this could be a transformative event for the commercial building industry. If the wrong building attributes are selected or if they are weighted incorrectly, we could have another green point system that distracts young architects and inexperienced building managers.

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  • The DOE has decided to pilot and implement a commercial building Asset Rating system that will evaluate and score the physical characteristics that define the energy efficiency of commercial buildings. This new DOE “AR” will be in addition the EPA’s ENERGY STAR program which scores the actual energy consumption of commercial buildings.

    The DOE is asking for feedback from interested parties.

    Here are the key issues that I have commented on:
    • Can buildings that are performing poorly (with low ENERGY STAR scores) publicize a good Asset Rating score and hide their poor performance? Or should buildings claiming high Asset Ratings be required to disclose how they are actually performing?
    • Should the new AR system use the ENERGY STAR scoring system (0 to 100) or a different one?
    • What building attributes should be on the input worksheet and how should they be weighted in the final score?

    If the right building attributes are selected by the DOE this could be a transformative event for the commercial building industry. If the wrong building attributes are selected or if they are weighted incorrectly, we could have another green point system that distracts young architects and inexperienced building managers.
    Are you sure you want to
    Your message goes here
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  • 1. DOE docket: EERE–2011–BT–NOA–004 Sherwin Comments on DOE Commercial Building Asset Rating Program Suggestions from Elton Sherwin, venture capitalist and author of Addicted to Energy: Innovative Advanced Energy Saving Features As a venture capitalist, one of my major concerns with asset ratings is they ignore innovation. New products, technical breakthroughs and some design innovations are usually omitted from asset ratings. Recommendation: Encourage architects to itemize advanced energy saving features in the rating report. They do not need to influence the asset rating score. This provides a register for innovative assets and will encouragement invention and experimentation.1 Responses to Specific Questions in the RFI Rating Scale: First choice: Match the ENERGY STAR score. A new scoring methodology will create confusion in the industry (even if it is better). Second choice. A scaled, inverted BTU/sq. foot score. See recommendations in Energy Efficiency and Sustainable Design Standards for New Federal Buildings: pages 46-47. Source vs. Site: Use the same methodology as ENERGY STAR (national source energy). Carbon footprint calculations: Please avoid giving buildings extra points based on their utility’s energy mix. Quality Assurance and Third Party Validation: As an investor my other major concern with asset ratings is their accuracy. The best quality assurance guarantee is to require disclose actual EUIs, Energy Star scores, and input worksheets. Require all building owners who publically disclose their Asset Rating also disclose their EUI and Energy Star score. It should be a condition of use.  For buildings with Asset Scores below their Energy Star rating, do not require additional validation. The high ENERGY STAR score validates the AR score.  For buildings with Asset Ratings above their Energy Star Rating, require outside validation.  For new buildings: Require a commitment to disclose future EUI and Energy Star rating as long as the Asset Rating is used publically.  For buildings with Asset Ratings in the top 25%, require complete transparency of the input worksheet: Post it on the DOE website. Disclose the buildings attributes that generated the high rating. This will discourage gaming. 1 Comments on EERE–2011–BT–NOA–004
  • 2. DOE docket: EERE–2011–BT–NOA–004 Sherwin Comments on DOE Commercial Building Asset Rating Program Additional Recommendations:  During the pilot: Validate that the most predictive building attributes are used. Statistically correlate the input worksheets with actual energy consumption. o Collect the four additional data elements used by the Portfolio Manager and automatically calculate the EUI and ENERGY STAR rating.  Require dual labeling. For existing buildings: Include the prior year’s ENERGY STAR score on the Asset Rating label. (as build/as used) What Are the Assets That Should Be Rated? Over a dozen asset rating methodologies have been tried in the US and all struggle to accurately predict energy use. Yet some building professionals can walk through an empty building and predict energy consumption. What are they looking for? Having studied the input worksheets for several failed European rating systems, I observe that they omit many of these Buildings with high assets that the professionals look for. Having interviewed hundreds numbers of T12s, of building professionals, these are the building assets most MR-16s, and Edison- predictive of energy consumption: socket ceiling cans are often poor Basic Assets performers Total Building Energy Demand  Electrical interconnect size (1,000 amp service, 10,000 amp service, etc.) Buildings with large master breaker boxes tend to use more power.  Total horsepower of all hardwired, fixed-speed motors, pumps, fans, and compressors. (Fixed-speed pumps, fans and compressors can be responsible for more than half the non-plug load electricity consumption in a building.)2 Lighting Efficiency  Total number of hardwired lighting fixtures3  Total number of hardwired sockets supporting Edison, MR16, and GU16 bases4  Total number of T12 bulbs5  Number of occupancy sensors (more is better).  Number of light level sensors that control light output (daylight harvesting)6 Basic HVAC  Total tons of A/C capacity (maximum) Oversized HVAC  Number of cooling towers systems are usually  Number of A/C compressors wasteful, regardless of  Maximum total BTU’s of heating from combustion rated efficiency  Total number of thermostats and temperature sensors  Total horsepower of all air-handling fans. (lower is better)  Percent of HVAC outside air goes through a heat exchanger (economizer) 2 Comments on EERE–2011–BT–NOA–004
  • 3. DOE docket: EERE–2011–BT–NOA–004 Sherwin Comments on DOE Commercial Building Asset Rating Program  During normal operations, when air enters occupied space, how many different velocity settings are there? 1, 2, 3 or more? (more is better)7 Windows  Percent of exterior walls that are windows.  Estimated percent of south and west-facing glass exposed to the sun at 3pm in Aug.  Total sq. ft. of exterior window shades (excluding the north side of the building)  Percent of exterior rooms with operable windows8 Professionals pay attention to these items. Please ensure the new DOE system does not omit them. Additional Metrics These more advanced metrics are in addition to those already mentioned. While there is some redundancy among these items, I would encourage you to test and correlate the following during the pilot. They may improve the accuracy of the asset rating. If they don’t, then the simpler metrics above should suffice. HVAC Fixed-speed fans are  Maximum total air handling capacity (cubic feet/min.)9 the telltale asset of  Number of occupancy sensors on the HVAC system an inefficient  Percent of A/C units that are variable output or multi-stage HVAC system  Are furnaces and boilers modulating?  Maximum energy required to drive all air handlers and fans10  Minimum airflow average. In conditioned space, when the HVAC system is moving air, what is the minimum amount of air it can move in a typical room?  Make, model and specifications of compressors, boilers and furnaces.  What percentage of rooms with exterior walls have individual zones?  Submeters installed on compressors, boilers and cooling towers.11 Total Building Energy Demand  Submeters installed for each floor?12  Monitors installed capable of user feedback of energy consumption per room?13 Lighting  Percent of ceiling fixtures controlled by occupancy or daylight sensors14  Percent of rooms with individual occupancy sensors  Percent of the lighting fixtures in areas with access to daylight automatically dim when daylight is present. Windows Solar heat gain in one room usually  Accurate solar heat gain calculations. increases energy  Make, model and specifications of the windows consumption many rooms 3 Comments on EERE–2011–BT–NOA–004
  • 4. DOE docket: EERE–2011–BT–NOA–004 Sherwin Comments on DOE Commercial Building Asset Rating Program 1 Innovative Advanced Energy Saving Features might include: Thermoelectric windows, white roofs, solar cooling, energy monitoring systems, feedback devices, humidity monitors, CO2 monitors, user-control of ceiling fixtures, advance building control systems. I would to help develop a starter list. This could include both a predefined list and a freeform “other” field. 2 A Grunfos Alpha is a good example of an adaptive pump that reduces energy consumption by 60 to 80%. Also, see Addicted to Energy pages 49 and footnotes 41 to 44. 3 If a lighting fixture is installed, it will be used. The more lighting fixtures a building has, the more electricity it uses. 4 Alternatively: Total number of incandescent bulbs in permanent fixtures (non-fluorescent, non-LED light fixtures hardwired including halogen fixtures, MR 16s, ceiling cans, etc.) Also, see the next footnote 5 Why not count LEDs, T5s and T8s? This number can be inferred: Once the total number of fixtures is counted, subtract the fixtures that need to be replaced: T12, Edison bases, the other incandescent bases. This is how the many energy pros do it. Look to see how many fixtures are on the ceiling and how many of them are candidates for replacement (T12s and incandescent fixtures). 6 This is a proxy for best-in-class digital ballasts. Buildings with great lighting systems have digital ballasts that adjust to light levels. 7 Audit pros, when they walk through a building, look for spots where they can feel air moving. This is a one of the key telltale attributes of an overactive, inefficient HVAC system. This “candle flicker” test is hard to write into a spec, but, in general, buildings that have large fans and blow air at one speed are much less efficient than buildings with smaller multispeed fans. Total HVAC energy consumption can decline dramatically as air movement is reduced. 8 In some climates and for some building types exterior windows are a predictor of building energy consumption. 9 This is the total ACH including fresh and stale air. This metric usually gives an advantage to displacement air systems. 10 The previous section had “the total horsepower of all air-handling fans” (nameplate). This metric is similar, but different and harder number to come by. This is total kilowatts used by all air handlers when they are on. It is a better measure of efficiency, but it may not be worth the extra effort. It might be worth allowing the nameplate number to be entered as the default and optionally allowing building owners to enter actuals, which would make sense for high efficiency fans. It is possible that simply identifying which motors are variable speed will be predictive enough. That is why the second item on in Total Building Energy Demand is Total Horsepower of all fixed-speed motors. 11 These do not need to be utility submeters. Another way to say this: Is the hardware installed to monitor the energy consumption of the building’s major subsystems. Buildings with these “submeters” use less energy. Also, see next note: 12 Some would argue that the existence of submeters is part of an operational rating. They are not. The installation of submeters not scored in Energy Star or any other operational rating. The installation of submeters is a key attribute (asset) of a building. If the architect specifies submeters, the building will, on average, use less energy. 13 See previous note. 14 These are sensors activated by people or photons. This includes manual timers that require users to turn on with each use (countdown timers) which are a form of occupancy sensors. This does not include time-of-day clocks without occupancy or light level sensors. This does not include building control systems that rely solely on time of day. 4 Comments on EERE–2011–BT–NOA–004