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By Rock Ridolfi Jr.
Energy Efficiency Article Use Policy
As the facility industry increasingly aims for higher performing buildings, facility managers should be aware of proven ways to prevent problems that can sabotage their facility's performance for years to come. Two steps are of critical importance: following a strategy of integrative design from the start of the process and involving a commissioning agent early on. These two steps can protect a building from a multitude of issues that can raise operating costs and cause occupant dissatisfaction.
Actions taken early in the new construction design process will obviously have lasting effects for the life of the building. However, and all too often, these early design actions result in equipment and exteriors that only meet code, with teams accepting standard control specs and sequences, and overemphasizing aesthetics by hiding equipment — at the cost of maintenance accessibility. Remember, in terms of operational efficiency, code is the least efficient building you’re allowed to build. And depending on your municipality, you may only have to build to standards that are 10 or more years old, rather than more recent energy codes such as IECC 2015 or ASHRAE 90.1-2013. This approach creates pitfalls in design, construction, and ultimately operations by setting predetermined limits to energy- and water-efficient operation for the future.
The solution is relatively simple: Adopt an integrated design approach. Fortunately, owners, architects, and general contractors are beginning to encourage a more integrative process. This includes having a commissioning authority engaged early in the pre-design and design conversation.
What is integrative design? The U.S. Green Building Council, in its LEED Reference Guide for Building Design and Construction, offers this definition, adapted from the American Institute of Architects: “an approach that involves people, systems, and business structures (contractual and legal agreements) and practices. The process harnesses the talents and insights of all participants to improve results, increase value to the owner, reduce waste, and maximize efficiency through all phases of design, fabrication, and construction.”
Here’s an abbreviated definition: “Integrative design engages the ownership, architect, engineer, and construction teams to identify the best method for delivering the owner’s project requirements within budget, on schedule, and to ensure efficient operation throughout the life-cycle.”
Adhering to an integrative process and including a commissioning authority from the start help align new construction activities with the transition into operations. Additionally, the integrative process will bridge the pit often created between construction and operations and will highlight the importance of peer review and open discussion. Efficient equipment and materials, including innovative technologies, are more likely embraced if considered early in design. For best results, the commissioning authority should be contracted directly with the owner, providing independent design, construction, and product selection peer review, system testing, and feedback.
Naturally, on a construction or major renovation, each person on the project has many success and horror stories from their past projects or from previous roles. These stories are untapped treasure troves documenting successes and failures that should be considered during the design process for new projects. The integrative process is the catalyst for bringing this history to the forefront, resulting in more creative and better functioning buildings in the future.
There is plenty to learn from both new construction and from operations, with lessons to apply to each other. For example, performing an ASHRAE energy audit on an existing building, you quickly learn about maintenance constraints for accessing equipment panels, various tenant concerns, and operational issues with building equipment.
Consider what happened after an energy audit pursued as part of a Leadership in Energy and Environmental Design (LEED) for Existing Buildings certification, which proved valuable during a future office development design discussion. The building in Washington, D.C., had a rooftop unit equipped with gas-fired morning warm-up and zoned fan-powered electric reheat VAV boxes. During the energy audit, which occurred during the winter, the morning warm-up was disengaged, and the VAVs were programmed to solely perform the necessary warm-up. This led to a net reduction in energy consumption and cost for the succeeding months. The building was able to maintain temperature throughout the office, and the overall added load on the VAV boxes was less than the original gas load for morning warm-up.
The energy conservation measures identified during the audit for that existing building proved beneficial for a separate, new construction development in Wisconsin. The owner engaged the full project team, including the commissioning authority, that worked on the D.C. office project. During early review of preliminary design, natural gas was identified as a new utility service that would serve the office’s domestic hot water load and provide fuel to the rooftop energy recovery unit for morning warm-up. The commissioning authority and mechanical engineer discussed an option to slightly upsize the fan-powered VAV electric reheat boxes while not using morning warm-up through the rooftop unit. The energy model verified this redesign to be sufficient at design conditions. A new gas service was eliminated from the new construction scope of work, and the domestic hot water system was redesigned to use point-of-use electric heaters instead of a centralized natural gas water heater.
An integrated design approach has another benefit. Past projects have sought to “value” engineer certain aspects of development without following an integrative design process. Although value engineering regularly results in lower first cost, it frequently results in higher operational expenses down the line.
That’s not to say there isn’t a place for careful value engineering. On a recent hotel development, value engineering resulted in the installation of several small exhaust fans and elimination of the energy recovery unit ventilator. Significant first cost was saved by eliminating long exhaust duct runs to a single common shaft to the energy recovery unit. The owners and design team had already engaged an energy engineer to analyze the building’s operation and were able to consider the first cost versus energy consumption analysis. Accounting for the use of the smaller exhaust fans versus eliminating the energy required to operate the recovery wheel and subsequent loss from the energy recovery transfer itself, the building would only increase annual consumption by less than 1 percent. In this case, thanks to the use of integrative design, value engineering occurred early in the construction process and did not affect equipment lead times.
Integrative Design Plus Early Commissioning Role Prevent Building Performance Problems
Integrated Design, Commissioning Aid Turnover from Building Construction to Operations