ASHRAE Journal - June 2010 - S30

ASHRAE Journal’s

Guide to Standard 189.1
Annual Energy Intensity (kBtu/ft2)

Climate Zone
150

City
Miami Houston Phoenix Atlanta Los Angeles Las Vegas San Francisco Baltimore Albuquerque, N.M. Seattle Chicago Boulder, Colo. Minneapolis Helena, Mont. Duluth, Minn. Fairbanks, Alaska

ClImAtE ZonE
100 50 0

1A 2A 2B

3B 3B 3C Coast Other

All Climate Zones

3A 3B – Coast 3B – Other 3C

90.1-2007 600

189.1

Annual Energy Intensity (kBtu/ft2)

BuIldIng typE
500

4A 4B

400 300 200 100 0

4C 5A 5B 6A 6B 7
Primary School Secondary School Quick Service Restaurant Supermarket Retail Small Hotel Large Hotel Small Office Medium Office Large Office Full Service Restaurant Strip Mall Hospital Outpatient Care Warehouse All Building Types

Energy savings attributable to Standard 189.1 vary substantially by climate zone and building type.

Energy performance modeling for Standard 189.1 used the climates zones from Standard 169-2006, the same climate zones as in Standard 90.1 with the 3B climate modified according to the DOE Commercial Building Reference Models for Energy Simulation.

Modeling Energy Savings
By Drury Crawley, Ph.D., Fellow ASHRAE; Paul Torcellini, Ph.D., Member ASHRAE; Nicholas Long, Member ASHRAE; Eric Bonnema, Associate Member ASHRAE; Kristin Field, Associate Member ASHRAE; Kent Peterson, P Fellow ASHRAE .E., evelopers of Standard 189.1—with its provisions for renewable energy, peak load reduction, and other efficiency improvements—were ambitious in setting the bar for energy performance. Their goal: an average 30% increase in site energy efficiency (i.e., a 30% decrease in site energy consumption) in comparison with Standard 90.1-2007. Does Standard 189.1 hit the mark? That was the question evaluated by the U.S. Department of Energy (DOE) and researchers at the National Renewable Energy Laboratory (NREL). With the completion of the standard, NREL was tasked to run a series of simulations to measure the order-of-magnitude, site-energy-saving potential of Standard 189.1, modeling the performance of commercial reference prototype buildings across 16 climate zones.
S30

The savings predicted by the initial modeling were impressive—and right on target. Indeed, the weighted energy savings across all modeled reference buildings was calculated to be 29.7% versus Standard 90.1-2007. Yet, the more revealing story is in the details, as demonstrated in Evaluation of Standard 189.1, issued by NREL in May 2010. The report reveals substantial differences in the results across climate zones and building types and also highlights the importance of miscellaneous loads, which are sometimes more significant than any other factor in determining energy performance. Understanding the variables driving energy performance under Standard 189.1 is vital in setting appropriate expectations and achieving successful outcomes.
Methodology and Assumptions

Any simulation is only as good as its underlying methodology and assumptions. NREL relied as much as possible on
June 2010

ASHRAE Journal’s Guide to Standard 189.1 ashrae.org

ASHRAE Journal - June 2010

Table of Contents for the Digital Edition of ASHRAE Journal - June 2010