Many CI projects with limited HVAC design scope find it more cost-effective to pursue Option 1. The usefulness of energy modeling as a design and optimization tool depends upon how wide the project scope is—the more systems that can be influenced in the design process, the better.
Developing a simulation model isn’t cheap—in the range of $10,000–$30,000 depending on the complexity of the project—but modeling can provide a favorable payback through design optimization and energy savings.
It is not easy to achieve 15% or better energy cost savings over current energy codes, such as ASHRAE 90.1-2007, from space heating, cooling, fans, and pumps alone, even though you can factor in HVAC load reductions from envelope improvements and lighting in the equipment energy use calculation.
If energy modeling has already been initiated by the base building project team, this is the way to go. If your project is located in a LEED-certified building, it’s likely that an energy model has already been done.
If your project has a larger HVAC scope, one that includes boilers, chillers, or air handling units, it may make sense to develop an energy model to assist in system sizing and selection.
Option 2 is best for projects with unique mechanical systems and energy efficiency strategies that are not included in Advanced Buildings: Core Performance Guide, thus not fitting well with Option 1.
Find out if it’s feasible to pursue this option. You’ll need to have (or be able to generate) a computer-based energy model running on approved software.
It’s a good idea at this stage to have your mechanical engineer meet with the base building engineer or manager to get detailed information on the possibility of adding controls and outside air intake—and to explore the possibilities of improving the efficiency of the system as a whole
