Rating System

LEED BD+C: New Construction

Rating System Version

v2 - LEED 2.1

Inquiry

Four energy-efficiency measures, which are not covered under ASHRAE 90.1-1999 or the LEED Energy Modeling Protocol, are outlined below for a 106,000 square foot chemistry research laboratory building with numerous lab fume hoods. These four measures generate significant energy cost savings. Based on the following USGBC Credit Rulings posted on 06/07/2001, 06/27/2001 and 01/20/2002: "To document savings for [energy reducing strategies not covered under ASHRAE 90.1-1999 or the LEED Energy Modeling Protocol], follow the ECB Exceptional Calculation Method. See Section 11.5 of the ASHRAE 90.1 User\'\'s Manual. Under the ECM, schedule variations may be used as a basis of engineering calculations for discrete measures that are precluded by the reference standard or the LEED EMP." We assume each energy-efficiency measure listed below should be modeled discreetly and "exceptional" savings must be subtracted from the Design Energy Cost in the same fashion as renewable energy. Based on the USGBC\'\'s LEED Credit Ruling posted on 11/09/2001: "It is acceptable to use [the same simulation tool that is used for the base simulation] to triangulate on projected savings for discrete measures that can ONLY be approximated through schedule manipulations." We assume that these Exceptional Calculation Methods (ECM\'\'s) are to be performed using the same simulation tool that is used for the base simulation. For the first three energy-efficiency measures listed below, a corresponding reduction in energy use can only be approximated by altering the Base Building schedules (based on sound engineering judgement). Therefore, we hereby request preliminary approval for the first three energy saving measures listed. Hourly schedules for lighting power density and fumehood exhaust in both the Design Building and Base Building are available for each case for review. 1. Lighting Occupancy Sensors When motion and/or infrared sensors determine a space to be unoccupied for a period of at least 15 minutes (adjustable), lighting within the space is automatically reduced to minimum levels. 2. Fumehood Zone Presence Sensors When locally mounted infrared sensors determine the zone in front of a particular fumehood to be unoccupied for a period of at least 15 minutes (adjustable), laboratory exhaust quantities shall be adjusted to reduce sash velocity from 100 fpm to 70 fpm for that individual fumehood. 3. Fumehood Occupancy Sensors Similar to Lighting Occupancy Sensors, when motion and/or infrared sensors determine a space to be unoccupied for a period of at least 15 minutes (adjustable), laboratory exhaust quantities shall be adjusted to reduce the minimum total room air change rate from 12 ACH to 6 ACH. Additionally, we request preliminary approval for the following energy saving measure, to be modeled as noted below: 4. Laboratory Air Cascading A portion of the makeup air required for fumehood exhaust shall be delivered to offices and support areas and then "cascaded" to labs via a ducted transfer air system. Ducts shall be sized so that the external pressure drop realized along the path of the transfer air shall be a maximum of 0.05" w.g. The Exceptional Calculation Method proposed would compare two analogous air-handling system (one for office/support areas and one for the laboratories), by breaking the air-handling system into two discreet pieces, to facilitate comparison of the Base and Design building models.