The intent of this credit is to "Achieve increasing levels of energy performance above the baseline in the prerequisite standard to reduce environmental and economic impacts associated with excessive energy use." The requirements of Option 1 of this credit are as follows: - Demonstrate a percentage improvement in the proposed building performance rating compared to the baseline building performance rating per ASHRAE/IESNA Standard 90.1-2004 (without amendments) by a whole building project simulation using the Building Performance Rating Method in Appendix G of the Standard. Per Appendix G of the Standard, table G3.1.3.7: The baseline requirement is as follows: - Since the conditioned floor area is greater than 240,000 square feet, the baseline building chiller plant shall consist of 2 centrifugal chillers minimum with chillers added so that no chiller is larger than 800 tons, all sized equally. The exception that we would like to take is as follows: - We recognize the baseline requirement for centrifugal chillers on this size of project. Our experience with a number of recent projects similar in size and use to this project indicates that air cooled chillers are more cost effective over the long term investment. When analyzed as a total system in comparison to water cooled chilling systems, air cooled chillers offer several cost advantages. Advantages include less equipment to purchase, less equipment to install, smaller space use requirements, less maintenance, less refrigerant, and less water use. - We are requesting that air cooled chillers are allowed to be used when modeling the baseline building performance for this project.