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  • (This is a normative appendix and is part of this standard.)

    NORMATIVE APPENDIX C
    PERFORMANCE OPTION FOR ENERGY EFFICIENCY

    C1.GENERAL

    C1.1 Performance Option Scope.

    Building projects complying with Section 7.5, the “Performance Option,” shall comply with the requirements in Normative Appendix G of ANSI/ASHRAE/IES Standard 90.1 with the following modifications and additions. When a requirement is provided in this appendix, it supersedes the requirement in ANSI/ASHRAE/IES Standard 90.1. This appendix shall be used both for building projects demonstrating compliance with the requirements of this standard and for building projects demonstrating performance that substantially exceeds the requirements of this standard. Where stated in Normative Appendix G of ANSI/ASHRAE/IES Standard 90.1, the rating authority or program evaluator shall be the authority having jurisdiction (AHJ).

    Note to Adopting Authority: ASHRAE Standing Standard Project Committee 189.1 recommends that a compliance shell implementing the rules of a compliance supplement that controls inputs to and reports outputs from the required computer analysis program be adopted for the purposes of easier use and simpler compliance.

    TABLE C1.1 Modifications and Additions to Table G3.1 of Appendix G in ANSI/ASHRAE/IES Standard 90.1

    Proposed Building PerformanceBaseline Building Performance
    1. Design ModelNo modificationsNo modifications
    2. Additions and AlterationsIn addition to the requirements in Table G3.1(2)(a), work to be performed in the excluded parts of the building shall comply with Sections 7.3 and 7.4.No modifications
    3. Space Use ClassificationNo modificationsNo modifications
    4. SchedulesNo modificationsNo modifications
    5. Building EnvelopeException (3) of Table G3.1(5) shall be replaced with the following: The exterior roof surface shall be modeled using the solar reflectance and thermal emittance determined in accordance with Sections 5.3.5.3 and 5.3.5.4. Where test data are unavailable, the roof surface shall be modeled with a solar reflectance of 0.30 and a thermal emittance of 0.90.a. In addition to the requirements in Table G3.1(5), the baseline building designshall comply with Section 7.4.2, not including Section 7.4.2.8. b. The baseline building performance shall be equal to the lowest annual energy cost of the following four simulations: the building in its actual orientation and the building rotated 90, 180, and 270 degrees.Exception to (b): Building projects that qualify for Exceptions (1) or (2) to Table G3.1(5)(a) are not required to have the building model rotated. c. In addition to the requirements in Table G3.1(5)(f) and G3.1(5)(g), roof surfaces shall comply with Sections 5.3.4.3.
    6. Lightinga. In addition to the requirements in Table G3.1(6)(c), when lighting neither exists nor is specified, lighting power shall comply with Section7.4.6.b. When taking credit for daylight controls under Table G3.1(6)(f), credit may be taken only for lighting controls that are not required by Section 7.4.6. Credit for daylighting controls is allowed to be taken up to a distance of 2.5 times window head height where all lighting more than one window head height from the perimeter (head height is the distance from the floor to the top of the glazing) is automatically controlled separately from lighting within one window head height of the perimeter.In addition to the requirements in Table G3.1(6), lighting power shall comply with Section 7.4.6. Automatic and manual controls shall be modeled as required in Section 7.4.6.
    7. Thermal Blocks—HVAC Zones DesignedNo modificationsNo modifications
    8. Thermal Blocks—HVAC Zones Not DesignedNo modificationsNo modifications
    9. Thermal Blocks—Multifamily Residential BuildingsNo modificationsNo modifications
    10. HVAC SystemsThe HVAC system type and all related performance parameters in theproposed design, such as equipment capacities and efficiencies, shall be determined as follows: Where a complete HVAC system exists, the model shall reflect the actual system type using actual component capacities and efficiencies. a. Where an HVAC system has been designed, the HVAC model shall be consistent with design documents. Mechanical equipment efficiencies shall be adjusted from actual design conditions to the standard rating conditions specified in Section 7.4.3 and Normative Appendix C if required by the simulation model. b. Where no heating system exists or no heating system has been specified, the heating system classification shall be assumed to be electric, and the system characteristics shall be identical to the system modeled in thebaseline building design. Where no cooling system exists or no cooling system has been specified, the cooling system shall be identical to the system modeled in thebaseline building design. The HVAC system(s) in the baseline building design shall be of the type and description specified in Section G3.1.1, shall comply with the general HVAC system requirements specified in Section G3.1.2, shall comply with any system-specific requirements in Section G3.1.3 that are applicable to the baseline HVAC system type(s), and shall comply with Sections 7.3 and 7.4.3 under the standard renewables approach as described in Section 7.4.1.1.1. The equipment efficiency requirements in Section 7.4.3.1 do not apply to the baseline building design.
    11. Service Hot-Water Systems In addition to the requirements in Table G3.1(11), service hot-water usage is allowed to be lower in the proposed design than in the baseline building designif service hot-water use can be demonstrated to be less than that resulting from compliance with Sections 6.3.2, 6.4.2, and 6.4.3.The service hot-water system in the baseline building design shall use the same energy source as the corresponding system in the proposed design and shall conform with the following conditions: a. Where a complete service hot water system exists, the baseline building designshall reflect the actual system type using actual component capacities and efficiencies. b. Where a new service hot water system has been specified, the system shall be sized according to the provisions of Section 7.4.1 of ANSI/ASHRAE/IES Standard 90.1 and the equipment shall match the minimum efficiency requirements in Section 7.4.4 under the standard renewables approach as described in Section 7.4.1.1.1 and the supermarket heat recovery requirements in Section 7.4.7.2 The equipment efficiency requirements in Section 7.4.4.1 do not apply to the baseline building design.Where the energy source is electricity, the heating method shall be electrical resistance.
    12. Receptacle and Other LoadsNo modificationsIn addition to the requirements in Table G3.1(12), the baseline building designmust meet the requirements in Section 7.4.7; except for the equipment efficiency requirements in Section 7.4.7.1, the ENERGY STAR® requirements in Section 7.4.7.3.2, and equipment efficiency requirements in Normative Appendix B.
    13. Modeling Limitations to the Simulation ProgramNo modificationsNo modifications
    14. Exterior ConditionsNo modificationsNo modifications
    15. On-Site Renewable Energy SystemsThe reduction in the proposed building performance and annual CO2e of the proposed design due to energy generated by on-site renewable energy systemsshall be calculated as follows:a. Annual Energy Cost. The annual energy cost of the proposed designwith an on-site renewable energy system shall be calculated on an hourly basis and adjusted as follows.1. Thermal Energy Performance Calculation. The hourly thermalloads of the proposed design shall be reduced by the hourly thermal energy production of the on-site renewable energy system (but thermal loads shall not be reduced to less than zero). When the on-site renewable thermal energy production exceeds the applicable thermal demands of the building for any hour, theexcess generated energy may be used to displace thermal loads atother times, provided the system has the storage capability and storage losses are included in the calculation. The approved energy rate structure shall be applied to the reduced energy consumption.2. Electric Energy Performance Calculation. The total electricalenergy production of the on-site renewable energy system shall be calculated on an hourly basis and the energy cost of the proposed building performance shall be calculated by applying the approved electricalrate structure to each hours electrical usage, including any reduction from hourly electrical energy production of the on-site renewable energy system.Exception to (a): For building projects with no net metering agreement,feed-in tariff, or other electrical rate structure for net generated electricity,the cost of imported electricity from the grid is calculated by applying the approved electrical rate structure to each hour ’s electrical loads minus the hourly electrical energy production of the on-site renewable energy system,but the cost of imported electricity shall not be less than zero on a monthly basis.Electricity production of the on-site renewableenergy system which has a retail value in excess of the retail cost of electricity consumption on a monthly basis shall be credited as a reduction in energy costs to the building performance at the wholesale rate as follows.where
    Credit=cost reduction credit for month where retail value of exported electricity is greater than retail value of imported electricity
    ExRR=month’s value of exported electricity at retail rate
    ImRR=month’s value of exported electricity at retail rate
    ExkWh=total kilowatt-hours exported in month
    WR=average monthly wholesale rate for the region where the building located
    b. Annual CO2e. The annual CO2e of the proposed building thatincludes an on-site renewable energy system shall be equal to theannual CO2e of the imported energy to serve the proposed building (with reduced loads due to the on-site renewable energy system) minus the annual exported electricity produced by the on-siterenewable energy system multiplied by the electrical CO2e emission factor.Documentation: The documentation required in Section G2.5(a), (b), and(e) in ASHRAE/IES Standard 90.1 shall be made available to the AHJ upon request for all on-site renewable energy systems in the proposed design.
    The baseline building design shall include an on-site renewable energy systemthat generates an annual amount of energy equal to that required under the standard renewables approach as described in Section 7.4.1.1.1. The on-site renewable energy system shall reduce the annual energy cost and the annual CO2e.a. Annual Energy Cost. The reduction in annual energy cost of thebaseline building performance due to on-site renewable production shall be equal to the amount of on-site renewable energy production required in under the standard renewables approach as described in Section 7.4.1.1.1 multiplied by the average energy rate for the baseline building design. The average energy rate shall be equal to the calculated total annual cost of energy to serve the baseline building divided by the total annual site energy consumption of the building not including reductions in consumption from on-site renewable energy production. b. Annual CO2e. The reduction in annual CO2e of the baseline building due to on-site renewable production shall be equal to the amount of on-site renewable energy production required under the standard renewables approach as described in Section 7.4.1.1.1 multiplied by the average CO2e rate for the baseline building design. The average CO2e rate shall be equal to the calculated total annual CO2e for all types of imported energy used by the baseline building divided by the total annual site energy consumption of the building not including reductions in consumption from on-site renewable energy production.Exception to (b): When the proposed design qualifies for the exception to Section 7.4.1.1.1, an on-site renewable energy system shall not be included in the baseline building design.

    C1.1.1 Performance Rating Mandatory Requirements (Section G1.2 of ANSI/ASHRAE/IES Standard 90.1).

    In addition to the requirements in Section G1.2 of ANSI/ASHRAE/IES Standard 90.1, all requirements in Sections 5.3, 6.3, 7.3, 8.3, and 9.3 shall be met.

    C1.1.2 Trade-Off Limits (Section G1.3 of ANSI/ASHRAE/IES Standard 90.1).

    In addition to the requirements in Section G1.3 of ANSI/ASHRAE/IES Standard 90.1, future building components shall meet all requirements in Section 7.4.

    C1.1.3 Documentation Requirements (Section G1.4 of ANSI/ASHRAE/IES Standard 90.1)

    1. a.In addition to the requirements in Section G1.4(d) of ANSI/ASHRAE/IES Standard 90.1, the documentation list shall include compliance with the requirements in Section 7.3.

    2. b.In addition to the requirements in Section G1.4(e) of ANSI/ASHRAE/IES Standard 90.1, the documentation list shall identify aspects that are less stringent than the requirements in Section 7.4.

    3. c.In addition to the requirements in Section G1.4(f) of ANSI/ASHRAE/IES Standard 90.1, the documentation list shall include a table with a summary of CO2e by end use in the proposed building performance.

    C1.1.4 Renewable, Recovered, and Purchased Energy.

    On-site renewable energy systems and site recovered energy (Section G2.4.1 of ANSI/ASHRAE/IES Standard 90.1): The modeling requirements for on-site renewable energy systems in Section G2.4.1 of ANSI/ASHRAE/IES Standard 90.1 shall not apply and are superseded by Section 15, “Renewable Energy Systems,” in Table C1.1.

    Annual energy costs (Section G2.4.2 of ANSI/ASHRAE/IES Standard 90.1): Where on-site renewable energy systems or site-recovered energy are used, the baseline building design shall be modeled in accordance with the requirements in Section 15, “Renewable Energy Systems,” in Table C1.1. The requirements for baseline building design energy source in Section G2.4.2 of ANSI/ASHRAE/IES Standard 90.1 shall not apply.

    C1.1.5 Baseline HVAC System Type and Description (Section G3.1.1 of ANSI/ASHRAE/IES Standard 90.1).

    Exception (4) to Section G3.1.1 of ANSI/ASHRAE/IES Standard 90.1 shall be replaced as follows:

    Kitchens with a total exhaust hood airflow rate greater than 2000 cfm shall use system type 5 or 7 with a demand ventilation system on 75% of the exhaust air. The system shall reduce exhaust and replacement airflow rates by 50% for one-half of the kitchen occupied hours in the baseline design. If the proposed design uses demand ventilation, the same airflow rate schedule shall be used. The maximum exhaust flow rate allowed for the hood or hood section shall meet the requirements of Section 7.4.3.7.1 for the numbers and types of hoods and appliances provided for in the proposed design. For allelectric buildings, the heating shall be electric resistance.

    C1.1.6 Equipment Efficiencies (Section G3.1.2.1 of ANSI/ASHRAE/IES Standard 90.1).

    Section G3.1.2.1 of ANSI/ASHRAE/IES Standard 90.1 is superseded by the requirements of Section 10, “HVAC Systems,” in Table C1.1.

    C1.1.7 Ventilation (Section G3.1.2.6 of ANSI/ASHRAE/IES Standard 90.1)

    1. a.Exception (1) to Section G3.1.2.6 of ANSI/ASHRAE/IES Standard 90.1 shall be used only where DCV is not required by Section 7.4.3.2.

    2. b.Exception (3) to Section G3.1.2.6 of ANSI/ASHRAE/IES Standard 90.1 shall not apply.

    C1.1.8 Economizers (Section G3.1.2.7 of ANSI/ASHRAE/IES Standard 90.1)

    1. a.Outdoor air economizers shall be included in the baseline systems identified in Section G3.1.2.7 of ANSI/ASHRAE/IES Standard 90.1 for the climate zones and capacities specified in Table 7.4.3.3A.

    2. b.Exception (1) to Section G3.1.2.7 of ANSI/ASHRAE/IES Standard 90.1 shall not apply.

    C1.1.9 System Fan Power (Section G3.1.2.10 of ANSI/ASHRAE/IES Standard 90.1)

    1. a.System fan brake horsepower shall be 10% less than the values calculated using Section G3.1.2.10 of ANSI/ASHRAE/IES Standard 90.1.

    2. b.Fan motor efficiency shall meet the requirements of Section 7.4.7.1.

    C1.1.10 Exhaust Air Energy Recovery (Section G3.1.2.11 of ANSI/ASHRAE/IES Standard 90.1).

    Exhaust air energy recovery shall be modeled in the baseline building design as specified in Section 7.4.3.6.

    C1.1.11 System-Specific Baseline HVAC System Requirements (Section G3.1.3 of ANSI/ASHRAE/IES Standard 90.1).

    Heat Rejection (Section G3.1.3.11 of ANSI/ASHRAE/IES Standard 90.1): In addition to the requirements in Section G3.1.3.11 of ANSI/ASHRAE/IES Standard 90.1, the heat-rejection device shall meet the performance requirements in Table B-8.

    C1.1.12 Variable-Air-Volume (VAV) Minimum Flow Setpoints (Section G3.1.3.13 of ANSI/ASHRAE/IES Standard 90.1).

    Zone minimum airflow setpoints shall be modeled as specified in Section 7.4.3.4.

    C1.1.13 Building Performance Calculations (Table G3.1 of ANSI/ASHRAE/IES Standard 90.1).

    In addition to Table G3.1 of ANSI/ASHRAE/IES Standard 90.1, the baseline building design and proposed design shall comply with all modifications and additions in Table C1.1. All references to “Table G3.1” in Table C1.1 refer to Table G3.1 of Appendix G of ANSI/ASHRAE/IES Standard 90.1.

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