By: Guest Contributor Cindy Regnier
Source: enr.construction.com

Energy-efficient buildings are not living up to their promise. The problem is serious, yet somewhat puzzling. Efficient building technologies are becoming more and more available; government regulations and company policies are supporting a drive for energy efficiency more than ever and building energy performance targets remain low. Yet when high-performance buildings are delivered they are not matching expectations

The reasons for the performance deficit can be attributed to multiple issues. Building system and envelope modeling may be inadequate, possibly hampered by incomplete application of the tools—probably because they are not calibrated to actual operating conditions. Contractors may understand each building system well, but lack insight into how to cost-effectively integrate those systems to enable deeper savings at the whole-building level. Controls commissioning could be incomplete or nonexistent and may not address all energy savings opportunities. Building controls may be too complex, or the training too spotty, for occupants to use them wisely, so they simply override them.

Whatever the cause, the problem is serious. According to a 2008 New Buildings Institute study, the energy use intensity of a building’s measured performance can end up being twice as much of that calculated for the modeled design, especially where buildings were designed for low energy performance. With increasing corporate scrutiny on building energy use and costs—and local energy disclosure laws bringing greater transparency to those issues—architects, engineers, construction firms, and owners (AECOs) need to find ways to ensure a better match between expectations and results.

New approaches for developing building designs and delivering their performance as intended are needed. Solutions exist on both the design and operations side that can lower the risk of a project underperforming. On the operations side the use of systems level energy information and benchmarks can be used to track and manage performance to align with expectations. Programs to continuously commission the building systems can also help. On the design side, one method of closing the gap between design projections and operations is to extend the concept of the typical construction mock-up to a systems-level performance mock-up; testing the constructability, controls integration, and performance of design conditions during the design process. This process can result in an improved design and a calibrated model that is attuned to actual operations and can be used to complete building design.

Up until now performance based mockups would have been difficult to implement – requiring a functioning shell and conditioning system to be provided for each project. A new building technologies testing facility at Lawrence Berkeley National Laboratory’s (LBNL) campus – FLEXLAB (Facility for Low Energy eXperiments in Buildings) – fills this gap by providing a platform that can be used for performance based mockups. The testbeds can be modified to simulate specific integrated and commissioned building systems—including HVAC systems, lighting, windows, envelope, plug load control systems—so their interactive performance can be observed, measured and optimized. Utilities, AECOs, and manufacturers can use the facility to develop, demonstrate, and verify the performance of innovative building energy-efficiency technologies and systems in a controlled, flexible environment.

As a result, projects can lower risks by providing early opportunities for design, construction, simulation, O&M, and controls efficiency improvements, which can reduce change order generation, as well as post-construction commissioning costs and time. Commissioning agents, architects, future occupants, and contractors can all visit the mockup to provide feedback on the proposed design, ensure that all the technologies work well together, and learn how to use the new systems effectively. FLEXLAB provides a platform for construction projects to take the steps needed toward guaranteeing energy performance.

Buildings play a critical role in our environment, both in the engagement we have with them during the hours of the day, and as an instrument that consumes precious global resources. With recent news of irreversible damage occurring in Antarctica’s ice shelves the warning messages are clear. We’re in a time when it’s imperative that we ask our buildings to step up to their potential to reduce energy use and address climate change. We now have the tools and processes in our hands to deliver low energy buildings that perform as intended, the question is will we try.

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