Page 179 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

LEED Ener gy and Atmospher e 157

FIGURE 4.1.3 Trane energy wheel for pretreating incoming air to the HVAC system. (Photograph
Courtesy of Trane.)

the approach and calculations that the project team and engineers other than the energy
modeler may find useful in acquiring a general understanding of LEED energy credits, as
well as how this credit can interrelate with other credits. Some of these items are as follows:

• Both an annual baseline and an annual design energy model are established. They
are based on annual energy costs and do not include any building construction or
first costs (design, material, or installation costs) for the systems. The dollar values
are based on either the local energy utility rates or, if these are not available, the
default state average rates as published annually by the US Department of Energy
(DOE) Energy Information Administration and available at www.eia.doe.gov. The
2003 Commercial Sector Average Energy Costs by State (CSAECS) on the U.S.
Department of Energy (DOE) website were compiled in the version 2.2 Reference
Guide with CSAECSE and CSAECSF representing the electrical and natural gas
i i
costs, respectively, for state i. These values are given in Table 4.1.3.
• The baseline and design models must be based on the ASHRAE/IESNA
Standard 90.1-2007 App. G, Building Performance Rating Method. This is the
method used to quantify exceedance of Standard 90.1. The energy cost budget
(ECB) method in Section 11 of this same standard was accepted as a rating
method in earlier versions of LEED but is no longer accepted.
• The numerical results of the baseline annual energy model are referred to as the
baseline building performance (BBP), and the design annual energy costs as
determined by this model are referred to as the proposed design energy model
(PDEM). The energy model values include both regulated and process