Our project involves a new 817,000 square feet facility located designed for the production and storage of multiple milk-based products. The project is targeting a LEED Silver certification, which includes earning points under EAc1. The project includes two process efficiency improvement measures for which we will submit exceptional calculations for documenting savings. We would like to verify that the assumptions and supporting documentation are acceptable. High Efficiency Steam Boiler Plant The boilers installed in the facility include two (2) 82,000 PPH steam boilers, which only serve the industrial processes. They do not serve any HVAC loads Design Performance - The as-designed steam boilers have a thermal efficiency of 83%. This is based on manufacturer\'s performance data. - Each as-designed steam boiler has a stack economizer and a condensing stack economizer. Together they increase efficiency by 12%. The economizers are used to preheat boiler feed water. - In addition, rejected heat from the process water systems is used to preheat boiler cold-water make up (138 GPM) from 70 F to 110 F through a plate and frame heat exchanger. This adds an additional 2% savings to the overall thermal efficiency of the boilers. - Manufacturer\'s data and engineering calculations will be supplied to support the efficiency claims listed above. The data will include inlet and outlet flows, temperatures, pressures, and enthalpies. The overall efficiency will be calculated based on the rated boiler efficiency and the additional heat reclaim. Baseline Performance - The baseline steam boiler efficiency is assumed to be consistent with the ASHRAE 90.1-2004 minimum efficiency requirements for large boilers. From Table 6.1.8F, the combustion efficiency for a gas-fired boiler > 2.5 MBtuh is 0.80. Thermal losses of 2% are assumed from the boiler shell. Thus, the thermal efficiency of the Baseline steam boiler is assumed to be 78%. Exceptional Calculation Approach The DOE-2.2 computer program will be used to model the steam boilers based on the facility process loads, equipment thermal efficiency, and part load performance. Refrigerated Warehouse Building Design The as-designed refrigerated warehouse has a reduced footprint due to the incorporation of an automated mechanical storage and retrieval system, which reduces aisle size requirements since fork lift maneuvering is no longer required. The design team compared the two design options and determined that the floor area for the automated warehouse is ~ 25% of that determined for the typical warehouse. In addition, the as-designed warehouse operates in a lights out environment except for maintenance, which requires lights on for ~ 1% of the year. Examples of recently constructed warehouses providing similar service without automated storage will be provided to document that this is typical of new design. Design Performance - Foot print of 110,600 square feet, height of 112 feet based on construction drawings - Lighting power density of 0.8 W/ft2, lights on 0.7% of the time (lights out facility) - Building maintained at 42 F Baseline Performance - Footprint of 469,800 square feet, height of 112 feet. The footprint and height is based on vendor\'s detailed engineering calculations that compares the design, capital costs, and estimated operating costs for an automated and non-automated facility. - Lighting power density of 0.5 W/ft2 (per ASHRAE 90.1), lights on100% of the time since it is continually operated. - Building maintained at 42 F Exceptional Calculation Approach The DOE-2.2 computer program will be used to determine energy costs for a revised baseline building that includes a larger refrigerated warehouse without automation.
The project team seeks verification of the approach to account for and document process energy savings. Specifically, the project team requests verification on the design and baseline cases for two boilers intended for process use, and for a reduction in footprint and lighting availability in the design case as compared to a larger, non-automated warehouse facility. The approach used for arriving at an appropriate baseline for the steam boiler plant seems reasonable. The reduction in floor area for the proposed design (automated case); is not permissible under Table G3.1, No.1 of Baseline Building Performance in ASHRAE 90.1-2004. The baseline building must be modeled with identical conditioned floor conditions as the proposed design. It is recommended that any savings associated with the automated operation in the proposed design be documented through the use of an exceptional calculation method (Section G2.5 of ASHRAE 90.1-2004, Appendix G) that supplements the procedure required per ASHRAE 90.1-2004, Appendix G. If credit is taken for measures including but not limited to lighting power density, occupant density, equipment power density, or floor area reduction, please provide sufficient justification in the submittal.