Created on LEED Interpretation

ID#

10497 ASHRAE 90.4 Data Centers Ruling

Credit NameEA103 - Minimum energy performance
Credit CategoryEnergy & atmosphere
International ApplicableYes
Campus ApplicableNo

Rating System

LEED BD+C: Data Centers

Rating System Version

v4.1 - LEED v4.1, v4 - LEED v4

Inquiry

Data centers have large, complex energy use that is not as widely understood or regulated from an energy code perspective. Traditionally, the ASHRAE 90.1 standard has not provided any guidance on what the minimum performance should be for electrical distribution systems for data centers. Recently, ASHRAE published the 90.4-2016 standard that provides guidance and maximum electrical losses for two different size data centers (less than and greater than 200 kW) and for three different components (or segments) of the electrical distribution system (Incoming Electrical Service, UPS Segment, and ITS Distribution Segment). The standard also creates an overall energy efficiency metric, the Electrical Loss Component that is the composite of the efficiencies of each of the three components defined. We are seeking confirmation that ASHRAE 90.4-2016 can be used to establish a baseline electrical system efficiency for data centers for the electrical distribution system. If approved, the process for documenting the Proposed Case electrical system efficiency would be to calculate each of the three component efficiencies, per ASHRAE 90.4-2016, and provide supporting documentation that outlines these calculations and includes back-up documentation for any equipment efficiencies used in that calculation. The resulting baseline and proposed case efficiencies and energy savings associated with the proposed electrical system design could then be summarized in a report or input into the USGBC Data Center Calculator to communicate the findings to the GBCI and review team.

Ruling

The applicant proposes to use the Electrical Loss Component (ELC) calculated in accordance with ANSI/ASHRAE Standard 90.4-2016, Section 8 in lieu of the Electrical System Efficiency calculated in the LEED Data Center Calculator. In ASHRAE Standard 90.4-2016, the ELC is calculated based on maximum loads at two separate IT loads (100% and 50% of IT design load for Single Feed UPS; and 50% and 25% of IT design load for Dual Feed UPS). The proposed approach is acceptable. However, if averaging the energy results for the project at 100% IT design load with the energy results for the project at startup IT loads, the ELC may only be used in conjunction with the 100% IT design load energy model, or with a startup IT load that represents 50% of IT design load for single feed UPS or no UPS configurations, or 25% of IT design load for active dual feed UPS systems. The documentation must specifically indicate the relevant maximum Electrical Loss / Efficiency Total from Table 8.2.1.1 or 8.2.1.2 of the Standard, and must be sufficient to confirm that the Electrical System Efficiency has been determined consistent with Standard 90.4: a. Provide submittal drawings consistent with the requirements of Section 8.4.1. b. Provide ELC calculations with the same level of detail as is provided in the Examples provided in Appendix C. c. UPS Segment Efficiency: Losses shall be based on manufacturer’s stated losses based on manufacturer’s stated efficiencies per Section 8.3.1.5. d. ITE Distribution Segment Efficiency: The longest path with the Electrical Component Efficiency: Indicate whether the rated or unrated equipment values have been used. For rated equipment, the values used in the calculations shall be the manufacturer’s numbers as derived from standardized testing per Section 8.3.1.9(a). For unrated equipment, provide verification that the efficiency values or losses have been verified per Section 8.3.1.9(b).

Description of Change

Projects pursuing LEED v4/4.1 BD+C: Data Centers certification and other D+C projects with data center spaces within the project have inquired as to how they can use ASHRAE 90.4, Energy Standard for Data Centers to document energy efficiency improvements under EA prerequisite Minimum Energy Performance and credit Optimize Energy Performance. Standard 90.4 is a performance-based design standard that offers the design components for mechanical load (MLC) and electrical loss (ELC).

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