Our project is an aquatics center owned and operated by the City of Henderson in Nevada. The adjacent property has a senior center also owned by the City. Both buildings are being designed by two separate A/E teams, and are registered as separate LEED projects. For contractual reasons the two buildings need to be submitted as separate LEED projects. However, the two buildings share a heat-pump building loop that will either be connected to a cooling tower/boiler central plant or an underground well-field loop. The sharing of the building loop is intentional since it allows both buildings to reject heat to the pool water. The sharing of the central plant/ well field also allows the two buildings to take advantage of the diversity of loading of the two buildings in sizing the heat rejection capacity. In this scenario, modeling either building separately will fail to accurately account for the way the loads are shared across the two buildings; especially the heat rejection into the pool water. Hence, we propose to build a common energy model for the baseline and design for both buildings and establish energy savings and estimate the EA Credit 1 points for the combined model. We would then apply these estimated points to both buildings. Conceptually this is the reverse of a campus energy approach where you are allowed to do a weighted average of separate building energy models to for EA Credit 1 for the entire campus. In this case there will be a common model that will be used to document EA Credit 1 for two separate LEED projects. From the perspective of either building, doing this averages the energy performance across the two buildings; and one of the buildings is likely to lose some energy efficiency and the other will gain some. The owner and design teams are ready to live with this. Since the energy model more closely reflects the building this approach allows for a more accurate model and energy estimates, and also sets up the correct model for the comparison with the energy data for the M&V Credit. We would like you to confirm that this approach is acceptable.
The CIR is requesting permission to use a single energy model that incorporates two separate facilities (with shared mechanical systems) in the submission of two separate LEED registered projects. Normally a project team should use the methodology described in the LEED-NC Application Guide for Multiple Buildings and On-Campus Building Projects (hereby referred to as the Multiple Buildings App Guide) or in the LEED-NC v2.2 EAc1 CIR Ruling dated 11/3/2006. However these methodologies assume a standard central-plant set up, where each building only interacts with the central plant. In this case it is acceptable to create an energy model with both buildings in the same model, and thus effectively create a single "facility" with the same end result for EAc1 applied to each building ONLY because there is direct energy transfer between the two buildings that could not be represented using a standard central plant. Guidance for larger facilities connected to a central plant or with shared systems is forthcoming. The separate projects will have to submit for certification using the methodology outlined in the Multiple Buildings App Guide section titled "Certifying new buildings where each new building is constructed to a set of standards but will receive an independent rating based on achievement of credits beyond the standards," which will have to specifically be arranged with USGBC staff prior to the first building being submitted.Update April 15, 2011: Please note that all 2009 projects in multiple building situations must follow the 2010 Application Guide for Multiple Buildings and On-Campus Building Projects, located here: https://www.usgbc.org/ShowFile.aspx?DocumentID=7987. 2009 project teams should check this document for up to date guidance on all multiple building issues.