The energy-savings potential of electrochromic windows in the UScommercial buildings sector

Technical Report · Fri Apr 30 04:00:00 EDT 2004

DOI:https://doi.org/10.2172/891618· OSTI ID:891618

Lee, Eleanor; Yazdanian, Mehry; Selkowitz, Stephen

Switchable electrochromic (EC) windows have been projected to significantly reduce the energy use of buildings nationwide. This study quantifies the potential impact of electrochromic windows on US primary energy use in the commercial building sector and also provides a broader database of energy use and peak demand savings for perimeter zones than that given in previous LBNL simulation studies. The DOE-2.1E building simulation program was used to predict the annual energy use of a three-story prototypical commercial office building located in five US climates and 16 California climate zones. The energy performance of an electrochromic window controlled to maintain daylight illuminance at a prescribed setpoint level is compared to conventional and the best available commercial windows as well as windows defined by the ASHRAE 90.1-1999 and California Title 24-2005 Prescriptive Standards. Perimeter zone energy use and peak demand savings data by orientation, window size, and climate are given for windows with interior shading, attached shading, and horizon obstructions (to simulate an urban environment). Perimeter zone primary energy use is reduced by 10-20% in east, south, and west zones in most climates if the commercial building has a large window-to-wall area ratio of 0.60 compared to a spectrally selective low-e window with daylighting controls and no interior or exterior shading. Peak demand for the same condition is reduced by 20-30%. The emerging electrochromic window with daylighting controls is projected to save approximately 91.5-97.3 10{sup 12} Btu in the year 2030 compared to a spectrally selective low-E window with manually-controlled interior shades and no daylighting controls if it reaches a 40% market penetration level in that year.

• Research Organization: Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE. Assistant Secretary for Energy Efficiency andRenewable Energy. Office of the Deputy Assistant Secretary for TechnologyDevelopment. Office of the Building Technologies Program
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 891618
• Report Number(s): LBNL--54966; BnR: BT0304030
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
CALIFORNIA
CLIMATES
COMMERCIAL BUILDINGS
DAYLIGHTING
ILLUMINANCE
MARKET
OFFICE BUILDINGS
ORIENTATION
PERFORMANCE
SHADING
SIMULATION
WINDOWS