System fan power is calculated per ASHRAE 90.1-2010 Appendix G3.1.2.10, where for the systems 3 through 8 fan motor efficiency is part of the formula. The standard says "Fan Motor Efficiency= the efficiency from Table 10.8B...". I can't find any errata of ASHRAE 90.1-2010 neither for this sentence nor for data of Table 10.8B.
However, it seems the Minimum Energy Performance Calculator - ASHRAE 90.1 - 2010 (v05) and as well the EXCEL tool from 7 group "7group-Appendix-G-Fan-Power-Calculator" (source: https://sevengroup.com/wp-content/uploads/2018/04/7group-Appendix-G-Fan-...) uses ASHRAE 90.1-2010 Table 10.8.A instead of Table B for the fan motor efficiency.
The document "ANSI/ASHRAE/IES Standard 90.1-2010 Performance Rating Method Reference Manual" (May 2016) of Pacific Northwest National Laboratory for the U.S. Department of Energy descriped efficiency data of ASHRAE 90.1-2010 Table 10.8B on page 3.133 Table 46 (source: https://www.pnnl.gov/main/publications/external/technical_reports/PNNL-2...)
What is the correct baseline fan motor efficiency data for LEEDv4?
When ASHRAE 90.1-2010 Table 10.8B is the answer both EXCEL tools described above use wrong efficiency data and provide wrong calculation results.
Tyler Thumma
7GroupLEEDuser Expert
61 thumbs up
August 30, 2020 - 2:25 pm
It appears Table 10.8B is correct. The 7group calculator was created using an older version of ASHRAE 90.1-2010 which simply referenced Table 10.8, so 10.8A was assumed because these are the same efficiencies as those referenced in 90.1-2013 and 90.1-2016. The 7group calculator has been corrected and the updated version will be uploaded shortly.
Simon Dellacher
2 thumbs up
August 31, 2020 - 4:18 am
Thank you for your reply. I have contacted USGBC to review the "Minimum Energy Performance Calculator - ASHRAE 90.1 - 2010".