COMNET offers many benefits to energy program administrators, including energy code enforcement personnel, energy rating programs like Design to Earn ENERGY STAR and ASHRAE’s Building EQ, green building recognition programs like USGBC’s LEED, and energy utility incentive programs. These programs have been quite effective for the last few decades. They encourage designers and owners to design, construct and manage energy efficiency buildings by offering incentives or special recognition. For new buildings, code minimum generally establishes the baseline from which incentives or recognition is offered.
Many energy efficiency programs already rely on modeled energy performance standards, but in the future this is expected to increase for a number of reasons. Modern energy standards are more complex and restrictive which will drive designers toward using a performance approach. Also, energy analysis software is becoming more sophisticated which is making it easier to use performance analysis. This shift has already happened in states like California that have tough energy efficiency standards coupled with advanced software used for compliance.
The movement toward more energy modeling can be a drain on resources because checking energy simulations is complex and there are a multitude of factors that can affect results. Special expertise is required. Most performance analysis requires the development of a baseline building and program administrators must verify that it is created correctly. Many inputs to the model are intended to be neutral, e.g. the same input applies to both the proposed and baseline building, and these too must be checked. New technologies are being introduced at a rapid pace and modeling techniques can’t always keep up, which leads energy modelers to use clever techniques to get around the limitations of the software. Energy standards used to establish the baseline building are sometimes difficult to understand, can be interpreted in different ways, and sometimes provide an incomplete specification of the baseline building. There are dozens of energy simulation packages that can be used for performance calculations and each produces results in a different format that makes it difficult to transfer into the data structures used by the program administrator.
These and other problems present challenges to program administrators as the world moves toward more performance standards, but COMNET can help. COMNET is a quality assurance program focused on standardizing energy modeling for buildings. There are several components to the COMNET program.
- The COMNET modeling guidelines are widely used and provide detailed and unambiguous guidance on more than 500 energy modeling inputs or building descriptors. The building descriptors are presented using generic language so as to not show a bias toward a particular software application. The guidelines may be used by energy modelers and program administrators alike. Several versions of the guidelines are offered to support different baseline standards and program requirements.
- Another black hole of time both for energy modelers and program administrators is translating data from the varied energy analysis programs on the market to the separate needs of individual energy programs. To address this problem, COMNET has developed a common data format which exists as an XML schema. The schema works like a Rosetta stone. Each software application can write to this common format and each energy program can read from this format. This is a classic case whereby a standard can save everyone time and effort.
- The ultimate COMNET goal, however, is that software automatically create the baseline building following the COMNET modeling guidelines and that the software assure that schedules of operation and other inputs are neutral between the rated building and the baseline building, as required by the guidelines. To pursue this goal, COMNET has developed a process for reviewing and accrediting software that meets its requirements. The creation of the baseline building would then be an automatic function of COMNET accredited software. When this goal is attained, the task of checking that the baseline building is correct would be largely eliminated and energy programs can focus on promoting effective measures and assuring that they properly work.
- Many building energy programs are overseen by regulators that sometimes challenge the modeling procedures used to estimate energy savings. COMNET offers advanced modeling tips for complex buildings like hospitals and laboratories as well as tricky design strategies like displacement ventilation and UFAD. These modeling tips have been vetted by hundreds of energy modelers and represent the best thinking. Requiring the use of these modeling tips could smooth regulatory review.
The COMNET program improves the quality of building energy models for energy programs that depend on energy simulations.