Most daylight harvesting schemes fall short of performance goals, says study

Analysis of daylighting control systems in 20 office and public spaces in Minnesota and Wisconsin shows that while the automatic daylight harvesting schemes are helping to reduce lighting energy in the buildings, most are not achieving optimal performance, according to a new study by the Energy Center of Wisconsin (ECW).

According to ECW, the median daylighting control system studied was saving 23% of lighting energy, including impacts on heating and cooling. This translated to 915 kWh saved for every kW of lighting controlled. But the average effectiveness (the energy saved versus energy saved with ideal control) of the controls was only 51%. This meant that almost half of the potential savings from these controls was not captured due to imperfect controls operation. Even worse, four of the 20 spaces studied had zero savings.

The low level of effectiveness, says ECW, is evidence of a lack of controls execution. The findings show that successful implementation of automatic daylighting control requires a significant commissioning effort to reach full energy-savings potential.

Read the full daylighting commissioning report from the Energy Center of Wisconsin.

As part of the report, ECW developed a tip sheet on commissioning and calibration and function testing of lighting controls. Recommendations include assigning a single person of the construction team to be responsible for verifying completion of all steps in the daylighting commissioning process, and proper training of the building owner/operator on the controls equipment and systems. Download the tip sheet (PDF)

(http://www.ecw.org/project.php?workid=1&resultid=494)

Learning objectives After reading this article, you should be able to: Understand issues of thermal performance and energy efficiency in relation to window and door systems; describe optimal detailing of the window-wall interface and how it contributes to building performance, sustainability, and occupant well-being; understand how durability contributes to sustainable windows/doors; and list sustainable O&M requirements for window and door systems.

| Jul 21, 2011

Falling Architecture Billings Index reflects decrease in design demands

This months Architecture Billings Index (ABI), provided by the American Institute of Architects, is almost a full point lower than last month’s reported score. June’s reading of 47.2 was short of the required 50 to achieve billings increases, making July’s reading of 46.3 an unwelcome sign of market tidings.