ASHRAE-90.1-2022- - Page 213

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a. Theoretical and empirical information verifying the method’s accuracy, and step-by-step documentation

of the exceptional calculation method performed, detailed enough to reproduce the results. b. Copies of all spreadsheets used to perform the calculations. c. A sensitivity analysis of energy consumption when each of the input parameters that are estimated is var ied from half to double the value assumed. d. The calculations shall be performed on a time-step basis consistent with the simulation program used. e. The energy cost budget and design energy cost calculated with and without the exceptional calculation

methods.

12.5 Calculation of Design Energy Cost and Energy Cost Budget 12.5.1 The simulation model for calculating the design energy cost and the energy cost budget shall be developed in accordance with the requirements in Table 12.5.1.

Exception to 12.5.1: Energy used to recharge or refuel vehicles that are used for off- site transportation

purposes shall not be modeled for the design energy cost or the energy cost budget .

12.5.2 HVAC Systems. The HVAC system type and related performance parameters for the budget build- ing design shall be determined from Figure 12.5.2, the system descriptions in Table 12.5.2-1 and accompanying notes, and the following rules:

a. Budget Building Systems Not Listed. Components and parameters not listed in Figure 12.5.2 and Table

12.5.2-1 or otherwise specifically addressed in this subsection shall be identical to those in the proposed design . Exception to 12.5.2(a): Where there are specific requirements in Sections 6.4 and 6.5, the component

efficiency in the budget building design shall be adjusted to the lowest efficiency level allowed by the requirement for that component type. b. Minimum Equipment Efficiency. All HVAC and service water-heating equipment in the budget build-

ing design shall be modeled at the minimum efficiency levels, both part load and full load, in accordance with Sections 6.4, 6.5.4.8, 7.4, and 7.5 based on the budget system type determined following Section 12.5.2(j) and capacity determined following Section 12.5.2(i). Chillers shall use Path A efficiencies as shown in Table 6.8.1-3 and be modeled using the performance curves specified in Table J-1 and included in Normative Appendix J. When using performance curves from Normative Appendix J, chiller minimum part-load ratio (ratio of load to available capacity at a given simulation time step) and minimum compressor unloading ratio (part-load ratio below which the chiller capacity cannot be reduced by unloading and chiller is false loaded) shall be equal to 0.25. Simulation programs that do not use performance curves are permitted to use an alternative simulation method that results in the same performance as the curves described in Normative Appendix J. c. Supply Fan Energy in Certain Package Equipment. Where efficiency ratings include supply fan

energy, the efficiency rating shall be adjusted to remove the supply fan energy . For budget system Types 3, 4, 6, 8, 9, 10, and 11, calculate the minimum COPnfcooling and COPnfheating using the equation for the applicable performance rating as indicated in Tables 6.8.1-1, 6.8.1-2, 6.8.1-4, and 6.8.1-15. Where a fulland part-load efficiency rating is provided in Tables 6.8.1-1, 6.8.1-2, 6.8.1-4, and 6.8.1-15, the full-load equation below shall be used:

COPnfcooling = 7.84E-8 × EER × Q + 0.338 × EER

COPnfcooling = –0.0076 × SEER [2] + 0.3796 × SEER

(applies to cooling efficiency only) COPnfheating = 1.48E-7 × COP47 × Q + 1.062 × COP47

(applies to Systems 6 and 9 heating efficiency only)

COPnfheating = –0.0296 × HSPF [2] + 0.7134 × HSPF

COPnfcooling = 0.3322 × EER - 0.2145 (applies to Systems 8 and 10 cooling efficiency only)

COPnfheating = 1.1329 × COP - 0.214 (applies to System 8 heating efficiency only)

where COPnfcooling and COPnfheating are the packaged HVAC equipment cooling and heating energy effi- ciency, respectively, to be used in the budget building design, which excludes supply fan power, and Q is the AHRI-rated cooling capacity in Btu/h. If Q is greater than 760,000 Btu/h, use 760,000 Btu/h in the calculation.

ANSI/ASHRAE/IES Standard 90.1-2022 (I-P) 211