Technical Support Document: Strategies for 50% Energy Savings in Large Office Buildings

This Technical Support Document (TSD) documents technical analysis that informs design guidance for designing and constructing large office buildings that achieve 50% net site energy savings over baseline buildings defined by minimal compliance with respect to ANSI/ASHRAE/IESNA Standard 90.1-2004. This report also represents a step toward developing a methodology for using energy modeling in thedesign process to achieve aggressive energy savings targets. This report documents the modeling and analysis methods used to identify design recommendations for six climate zones that capture the range of U.S. climate variability; demonstrates how energy savings change between ASHRAE Standard 90.1-2007 and Standard 90.1-2004 to determine baseline energy use; uses a four-story 'low-rise'prototype to analyze the effect of building aspect ratio on energy use intensity; explores comparisons between baseline and low-energy building energy use for alternate energy metrics (net source energy, energy emissions, and energy cost); and examines the extent to which glass curtain construction limits achieve energy savings by using a 12-story 'high-rise' prototype.