Chapter 1 Introduction 3) Chapter 2 Rationale for Zero Energy 4) Chapter 3 Zero Energy Buildings: Ongoing performance

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1 Summary Response To Feedback on the Preliminary Technical Peer Review for Advanced Energy Design Guide for Small to Medium Office Buildings: Achieving Zero Energy November 9, 2018 On August 31, 2019, a Preliminary Technical Review Draft of the Project Committee for the Advanced Energy Design Guide for Small to Medium Office Buildings: Achieving Zero Energy was issued. Following the review period (September 1-17, 2018), the Project Committee met on October 2-3, 2018 to review the feedback and recommendations received. The committee received 246 comments and recommendations from 12 reviewers. An additional 49 comments and recommendations from 3 reviewers were received after the review period had closed these additional comments may not be addressed in this summary response, but they were also reviewed and considered by the committee. Thank you to everyone that reviewed and commented on the draft and especially to those that specifically commented on the questions throughout the guide. All of the suggestions received were carefully considered by the Committee and the feedback has been very helpful to them. The following summary information documents the Project Committee s response to input received during the review. The summary is focused on the significant technical recommendations, especially those in which there was disagreement with what had been written or omitted. Following the general summary, the review input is summarized by chapter and section below. 1) General Remarks and Recommendations Per the direction of the AEDG Steering Committee, the guide uses the terminology and approach found in the DOE document, A Common Definition for Zero Energy Buildings ( The intent of this guide is to provide recommendations that present some ways, but not the only ways to achieve a zero energy building, so not all possible strategies will be included, especially specialty items. The guide does not propose that all buildings should go to zero energy, but rather is focused on helping buildings determine what level of energy efficiency (or EUI target) is appropriate such that the building could add renewables (if feasible) to get to zero energy. The document uses all climate zones defined in ANSI/ASHRAE Standard (CZ 0 through CZ 8). These climate zone definitions are consistent both in the US and internationally. The AEDGs are intended for new construction and major renovations, but the information contained may also be applicable for retrofits and existing buildings. While resiliency and grid optimization are not the intended focus, the guide will add information on these topics where possible. The AEDGs are design guides rather than operation and maintenance (O&M) guides but do attempt to address design for operability and maintenance. All recommended equipment, systems, and technology specified in the document are commercially available from at least two manufacturers. Tables and figures in this draft were preliminary and not reflective of what they will look like in the final publication. Figures and tables will be corrected, updated, and redrawn as needed throughout the guide. 60% Preliminary Technical Review Draft Page 1 November 6, 2018

2 Examples were requested throughout the guide and the committee continues to look for appropriate examples that can be added to further explain the text and recommendations. Terminology in the guide will be brought in line with current industry and ASHRAE terminology as appropriate. References will be added, corrected, updated, or eliminated as needed throughout the guide including references to appropriate industry standards and guidelines. Additional references will be added to direct readers to related or relevant content in other parts or the guide. Navigational hyperlinks between chapters and bookmarks will be included in the final publication. Please note that some of the general comments were more difficult for the committee to address as the commenter did not specify where the noted issue occurred in the guide. 2) Chapter 1 Introduction The language on occupant satisfaction will be revised and strengthened. The committee notes that using DC Power is not needed to get to zero energy although this a viable technology. The committee disagrees that construction of zero energy buildings costs more than other buildings. Multiple examples show that they can be built with no cost penalty. The committee will try to add data to the guide that illustrates this point. Case studies will also be added to support this position. The committee disagrees that systems must be more complex to achieve zero energy; in order to have persistence, simpler (or smarter) systems are recommended. The committee is verifying the parameters of the building model used and the building types covered by the guide. However, the guide cannot address all possible configurations of buildings. 3) Chapter 2 Rationale for Zero Energy The committee is reviewing the organization of this chapter for possible changes to improve flow of information and in regards to how the information best fits with Chapter 3. The committee is reviewing the Energy Loading Order section to determine what changes are needed to address the concerns expressed by reviewers. 4) Chapter 3 Zero Energy Buildings: Ongoing performance The committee is reviewing the organization of this chapter for possible changes to improve flow of information and in regards to how the information best fits with Chapter 2. The committee is reviewing the title of this chapter and will revise as appropriate once all content has been completed. The committee feels that that the EUI numbers need to follow the lead of the previous zero energy guide and be expressed in 3 significant digits. Information on 3 rd party certifications and awards will be added. Updates to the commissioning section of this chapter will include corrected terminology and acronyms, reference to Standard 211, and guidance on occupant instruction and feedback 5) Chapter 4 Building Performance Simulation This chapter is not intended to be a primer on creating an AHRAE 90.1 Appendix G or ECB energy model to demonstrate code compliance. 60% Preliminary Technical Review Draft Page 2 November 6, 2018

3 The best application of parametric models would be very early on in the determination of building configuration, shape and orientation, but they are likely beyond the scope of this document. The committee agrees that the guide should mention the types of specialized models often needed to represent technologies in a zero energy building. This chapter is not intended to be a discussion of strategies to attain the EUI goal, but rather a discussion of the modeling tools and process needed to identify those strategies. Specific guidance on strategies is found in Chapter 5 including thermal bridging, circadian rhythms, and shading options. The mechanical systems comparison section will be strengthened. 6) Chapter 5 How to implement Recommendations Building Siting and Planning The renewables tips in this section are more about early stage planning for renewables and their integration with the building. Grid interconnection is covered in the renewable energy section, but the committee will look to reference that information in the building planning section. Non-roof options for PV will be mentioned here and in the renewables energy section. Envelope The envelope section will be reorganized to flow better. There is growing evidence that lower leakage rates are being achieved, therefore the committee plans to keep the infiltration recommendation at 0.25 cfm/ft 2 and reduce the recommendation to 0.15 cfm/ft 2 for severe climates. They will also consider including sensitivity analysis for infiltration from the energy simulation results. Thermal mass is included in both envelope and HVAC because it needs to be considered in the architectural planning and it s a passive strategy, but it also has to be integrated with HVAC. The committee notes that thermal mass not exposed in the space is not effective in mitigating internal gains and external mass is not targeting internal heat gains. However, they will add in additional language to address commenters concerns. The entire thermal bridging section will be edited, revised, and streamlined. Drawings will be revised as appropriate and information based on 90.1 addendum av will be removed. The values in Table 5-3 are based on and are appropriate for zero energy buildings. The committee will consider including an additional mass wall value. The definition of below grade wall will be clarified. The section on insulating mass walls will be retained as it is not about the properties of thermal mass. Reference to moisture management will be moved. The thermal bridge information on columns will be revised to address crawl spaces and unconditioned parking garages. A side bar highlighting impact of occupant performance will be added. The committee does not plan to include vacuum glazing because it does not appear to be available from multiple manufacturers. The committee will look at adding guidance regarding to address concerns with durability, condensation and downdraft on room side low-e coating. Revisions will be made to the information on spandrel area to focus on key strategies for insulating spandrel areas. The section on glazing will be revised in regards to aluminum frames, but the guide cannot universally claim that thermally broken aluminum frames can achieve the same U-factors as 60% Preliminary Technical Review Draft Page 3 November 6, 2018

4 other frame materials. A word of caution will be added about the reduced performance of unnecessary additional framing that is aesthetic vs. structural. Daylighting Points on circadian stimulus and design response that are critical to address will be added. A sidebar on daylighting for indoor environmental quality will be included. The committee agrees that manual shades are poorly used. Emphasis will be added along with a discussion of the pros and cons of auto options. Passive glare control strategies will be added, including interior solutions such as occupant orientation, small partitions. The tip on Glare Control Shading will be edited to clarify that a blanket shade application is not suggested but that does not mean that shades are prohibited. The information on metrics will be moved closer to the beginning of the daylighting section. A combination of photos and illustrations/diagrams will be added and included. The 30% WWR recommendation will be edited to clarify that 30% is whole building and some facades might benefit from a high percentage of window area. A sidebar on lighting for improved indoor environmental quality (IEQ) will be added. Lighting Controls References to basic control systems and components will be added but the committee will not make a substantial expansion of the section. A note will be added to clarify that the guide is intended to specifically focus on control strategies and solutions important for zero energy design. Luminaire level lighting controls (LLLC) will be framed as a good option for a dynamic, modern workspace and shown in context to other control architecture options. A discussion on zoning will be added. Some text will be added to address sustained functionality of occupancy sensors for exterior applications (e.g., weather resistant, mounting location, zoning, panel location). Electric Lighting The committee disagrees that customers often require very high CRI specs that are above 80 CRI and not available in 125 lpw. Partition height is specifically referenced in EL-8. The committee notes that some of the recommendations questioned by reviewer are required by ASHRAE Standard Plug & Process Loads Plug Loads will be defined at the start of this section. The energy benefits of regenerative elevators will be added. Service Water Heating An additional column will be added to Table WH-3 to reflect efficiencies actually being achieved in the marketplace. The committee feels that low-volume end uses likely do not justify service from a central source with required recirculation and should be served with point-of-use water heaters. 60% Preliminary Technical Review Draft Page 4 November 6, 2018

5 HVAC The guide strives to provide synergies between the envelope and the mechanical systems, but the committee will look to provide more emphasis on reducing mechanical equipment energy. The guide cannot address all possible mechanical systems or configurations. Four representative systems have been selected, and users are encouraged to use other systems and utilize modeling to achieve EUI targets. The committee notes that providing relative energy consumptions comparison of the systems outlined in the guide would be misleading. Instead the modeling that supports the guide development have used the models to develop overall EUI targets and verify that each system supports those targets. The committee is working to streamline the information in this section and to be more consistent on the depth of coverage within the various how-to tips and recommendations. The entire section will be reorganized to put the more important information first. The fan coil system configuration has been updated to include heat recovery chillers and the description will be updated accordingly. The committee agrees that exhaust air heat recovery should not be used in mild climates and will clarify that in the text. System descriptions and labels will be updated to be more accurate. All references to water cooled chillers have been removed. Systems will now include dry cooler waterside economizers. Information from ASHRAE Standard 62.1 and Guideline 36 will be incorporated into the guidance where appropriate. The committee believes that right-sizing is a legitimate efficiency issue that needs to be discussed in the guide. A number of the how-to tips have been re-written to clarify or correct information as pointed out by reviewers. Renewable Energy The committee notes that this guide is focused on solutions at the project level. While community scale options and other models are viable options, they are beyond the scope of this guide. The use of RECS is not encouraged by the guide, the term is simply defined for educational purposes. Information on ground mounted options for PV will be added both here and the in the Building Planning section of Chapter 5. 60% Preliminary Technical Review Draft Page 5 November 6, 2018