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.
ENERGY EFFICIENCY MEASURE 1: It appears that altering the schedule to approximate energy savings from the lighting occupancy sensors (as described) fits within the context of the 90.1 Exceptional Calculation Method. When calculating the energy savings associated with these measures for EAc1, it is necessary to justify both the proposed and budget schedules for occupied hours and provide detailed space by space usage schedules that are both reasonable and defensible. The budget and proposed building should have the same lighting schedules for regularly unoccupied periods. Additionally, it may be possible to arrive at a reasonable estimate by manipulating the lighting power density in the proposed and design case. ENERGY EFFICIENCY MEASURES 2 AND 3: Fumehoods are considered process loads, which are not applicable to EA Prerequisite 2 and EA Credit 1. The appropriate treatment of laboratory process loads is the subject of numerous LEED CIRs. Please refer to the EAp2 credit ruling dated 12/15/03 and EAc1.1 credit ruling dated 12/15/03 for a discussion of the appropriate treatment of ASHRAE 90.1 non-regulated energy loads in EAc1. To maintain consistency with the referenced standard, optimization of non-regulated energy loads is recognized by award of an Innovation in Design (ID) credit rather than award of EAc1 points. For ID credit calculations, it appears that altering the schedule to approximate energy savings from the fumehood zone presence sensors and the fumehood occupancy sensors (as described) fits within the context of the 90.1 Exceptional Calculation Method. When calculating the energy savings associated with these measures for ID credit award, it is necessary to justify both the proposed and budget fumehood schedules for occupied hours and provide detailed laboratory usage schedules that are both reasonable and defensible. The budget and proposed building should have the same ventilation rates for regularly unoccupied periods. If any of the zones are internally load driven, the potential energy savings from reducing the ventilation requirements must account for the possibility of higher ventilation rate requirements imposed by internal loads. ENERGY EFFICIENCY MEASURE 4: The ECM proposal does not contain sufficient detail from which to make an informed determination. It is likely that it will be allowed during LEED certification review if ASHRAE 90.1 Section 11.5 guidance is followed (i.e., provide theoretical and empirical information verifying accuracy). Also consider this alternative approach: the lab could be modeled as a 100% outside air system for the baseline case but as a recirculating system for the proposed design. The outside air quantities and relief quantities for the office space would be modeled as identical. The fan power and schedule would be identical for the supply and exhaust systems for laboratory and office areas. To model the cascading system in the proposed design, the laboratory system recirculates the volume of relief air that would be cascaded from the office space to the laboratory space. The total amount of outside air drawn into the building is reduced in the proposed design by the amount of relief air that is cascaded from the office occupancy to the laboratory. The outside air ventilation volumes and exhaust volumes are identical for the two cases (the outside air discrepancy is due to a make-up air, rather than a ventilation air requirement). Applicable Internationally.