Our project is a 573,000 SF warehouse facility in a mild climate. The facility is designed to function as a distribution facility at a trucking hub used to store and transfer goods. The typical set-up for a project of this type in the region is to have no mechanical cooling, ventilation and heating (for freeze protection only, temperature set-point 45F) is provided by series of roof-top units with gas-fired furnace. These units are typically constant volume. Since this project is pursuing certification under the LEED-CS v 2.0 rating system, to attempt any points under EA credit 1, we have to follow ASHRAE 90.1-2004, Appendix G - Performance Rating Method. Following the ASHRAE 90.1-2004, Appendix G - Performance Rating Method for a project of this type and size, we will have to model the baseline system as a packaged rooftop VAV with reheat provided by a fossil fuel boiler. A project of this size and type would not have anything even close to this baseline system. Also the modeling protocol requires the project to be modeled with mechanical cooling. Due to the unique nature of the project and its sheer size, it appears that the credit requires the project to use more energy to show that it saves energy. To address this issue, we are proposing the following adjustment to the modeling protocol - Proposed building - Model as designed in terms of envelope, HVAC systems, lighting systems, power distribution and schedules of operations Baseline building - Use the ASHRAE 90.1 section 11 and model as system 11 without mechanical cooling. All other systems will be modeled at minimum required efficiencies as per ASHRAE 90.1-2004. All schedules will be modeled as in the proposed model. Also the outside air rates will be maintained as per the proposed model. We believe that this approach will allow the project to pursue energy efficiency and take credit for any measures that they may apply. We also believe that this variance will allow the integrity of the rating system as it will not require the team to spend extra energy and money to demonstrate achievement of a credit. While the team acknowledges that not all credits apply to all projects, it is very difficult to make a case for green building without demonstrating energy efficiency from the view-point of the owner.
The CIR is asking what to use for proposed and baseline systems to meet the requirements of ASHRAE 90.1-2004 while still fairly representing the warehouse nature of the project. The answer depends on whether the space is classified as conditioned, semi-heated, or unconditioned. As per the ASHRAE 90.1-2004 Users Manual, a space is "unconditioned" if it has no cooling and a heating system of less than 3.4 BTUH/SF. A space is considered "semi-heated" if it has a heating system with a capacity greater than 3.4 BTUH/SF, but less than the climate specific value that can be looked up on table 3.1 of the ASHRAE 90.1-2004 Standard. If a space contains a cooling system greater than 5.0 BTUH/SF or a heating system greater than that listed in Table 3.1, then it falls in the "conditioned" category. The above criteria are based on the total output capacity of the equipment. IF THE SPACE IS UNCONDITIONED OR SEMI-HEATED: ASHRAE 90.1 modeling protocol is based around typical occupied and conditioned buildings. It is not meant to address industrial/manufacturing "process" areas, which warehouses may fall under if they meet the requirements of unconditioned or semi-heated spaces. These spaces fall outside the realm of ASHRAE 90.1-2004 and the modeler is asked to include them in the model "as-is," meaning, in this case, including only a heating system and no cooling. The systems should be identical in both the baseline and proposed cases. If the project wishes to show energy savings due to the HVAC system in these areas, an Exceptional Calculation Method (ECM) must be used. See ASHRAE 90.1-2004 G2.5 for this procedure. IF THE SPACE IS CONDITIONED: If the heating provided to the space exceeds the thresholds set forth in Table 3.1 of ASHRAE 90.1-2004, then the standard modeling methodology should be used even if it results in systems that are different than the industry standard for the space type. Please note that typically in a warehouse facility there are some spaces that are fully conditioned (offices, break rooms, etc.). Please follow the standard ASHRAE 90.1-2004 Appendix G protocol for these areas. Applicable Internationally.