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Title: Lighting energy savings potential of split-pane electrochromic windows controlled for daylighting with visual comfort

Abstract

A simulation study was conducted to evaluate lighting energy savings of split-pane electrochromic (EC) windows controlled to satisfy key visual comfort parameters. Using the Radiance lighting simulation software, interior illuminance and luminance levels were computed for a south-facing private office illuminated by a window split into two independently-controlled EC panes. The transmittance of these was optimized hourly for a workplane illuminance target while meeting visual comfort constraints, using a least-squares algorithm with linear inequality constraints. Blinds were successively deployed until visual comfort criteria were satisfied. The energy performance of electrochromics proved to be highly dependent on how blinds were controlled. With hourly blind position adjustments, electrochromics showed significantly higher (62percent and 53percent, respectively without and with overhang) lighting energy consumption than clear glass. With a control algorithm designed to better approximate realistic manual control by an occupant, electrochromics achieved significant savings (48percent and 37percent, respectively without and with overhang). In all cases, energy consumption decreased when the workplace illuminance target was increased. In addition, the fraction of time during which the occupant had an unobstructed view of the outside was significantly greater with electrochromics: 10 months out of the year versus a handful of days for the reference case.

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1171807
Report Number(s):
LBNL-6152E
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Energy and Buildings
Additional Journal Information:
Journal Volume: 61C; Related Information: Journal Publication Date: 2013
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 29 ENERGY PLANNING, POLICY, AND ECONOMY; Building energy-efficiency, Daylighting, Control optimization, Electrochromic windows

Citation Formats

Software, Anyhere, Fernandes, Luis, Lee, Eleanor, and Ward, Greg. Lighting energy savings potential of split-pane electrochromic windows controlled for daylighting with visual comfort. United States: N. p., 2013. Web.
Software, Anyhere, Fernandes, Luis, Lee, Eleanor, & Ward, Greg. Lighting energy savings potential of split-pane electrochromic windows controlled for daylighting with visual comfort. United States.
Software, Anyhere, Fernandes, Luis, Lee, Eleanor, and Ward, Greg. 2013. "Lighting energy savings potential of split-pane electrochromic windows controlled for daylighting with visual comfort". United States. https://www.osti.gov/servlets/purl/1171807.
@article{osti_1171807,
title = {Lighting energy savings potential of split-pane electrochromic windows controlled for daylighting with visual comfort},
author = {Software, Anyhere and Fernandes, Luis and Lee, Eleanor and Ward, Greg},
abstractNote = {A simulation study was conducted to evaluate lighting energy savings of split-pane electrochromic (EC) windows controlled to satisfy key visual comfort parameters. Using the Radiance lighting simulation software, interior illuminance and luminance levels were computed for a south-facing private office illuminated by a window split into two independently-controlled EC panes. The transmittance of these was optimized hourly for a workplane illuminance target while meeting visual comfort constraints, using a least-squares algorithm with linear inequality constraints. Blinds were successively deployed until visual comfort criteria were satisfied. The energy performance of electrochromics proved to be highly dependent on how blinds were controlled. With hourly blind position adjustments, electrochromics showed significantly higher (62percent and 53percent, respectively without and with overhang) lighting energy consumption than clear glass. With a control algorithm designed to better approximate realistic manual control by an occupant, electrochromics achieved significant savings (48percent and 37percent, respectively without and with overhang). In all cases, energy consumption decreased when the workplace illuminance target was increased. In addition, the fraction of time during which the occupant had an unobstructed view of the outside was significantly greater with electrochromics: 10 months out of the year versus a handful of days for the reference case.},
doi = {},
url = {https://www.osti.gov/biblio/1171807}, journal = {Energy and Buildings},
number = ,
volume = 61C,
place = {United States},
year = {Fri Mar 15 00:00:00 EDT 2013},
month = {Fri Mar 15 00:00:00 EDT 2013}
}