Making Daylighting Work: Applying Cx to Avoid Daylighting Problems
Before They Happen
Joseph Deringer, Institute for Sustainable Building Performance
Prasad Vaidya, The Weidt Group, Inc.
Daylighting, hailed as a cornerstone of sustainable building design, has the potential to reduce lighting energy, which can be 40% or more of the energy cost of a commercial building. We find that daylighting control systems often do not provide the expected energy savings. In a risk-adverse construction industry, even limited failures can dramatically slow the advance of valid technologies. There are numerous reasons for failure. Natural light sources are complex and vary through the day and year, implementation requires coordination between different building design and construction trades, the documentation and specification of the controls equipment is often inadequate, and calibration after installation is rarely done well and can be confusing and time consuming.
Our 2007 NCBC presentation examined twelve case studies, from a sample of some 100 projects. From the analysis of these case studies we identified four typical modes of failure and provided a template for each mode for easier problem resolution. We identified problem areas in the design and implementation process, and we proposed a general set of Cx actions to increase the chances of daylighting success, including example Cx activities drawn from NIBS Guideline 3-2006 and ASHRAE Guideline 0-2005.
This year, we will discuss the application of Cx techniques to daylighting design projects. Beginning with Pre-Design and continuing through each design phase and into construction and Occupancy/Operations, we will show how various Cx techniques can be used to identify and resolve incipient problems. We will use three recent daylighting projects to demonstrate the procedures used. We based our procedures on the guidance provided in the ASHRAE-NIBS Total Building Commissioning series (GL-0, GL-1, and GL-3).
|