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ering the solar heat gain coefficient
to reduce cooling while 
maintaining the visual transmission of the
glass to capture 
daylight savings. However, harnessing
daylight in a build- 
ing poses asignificanttechnicalchallenge because ofthe great 
variability in daylight intensity. Achieving higher energy 
savings under these conditions requires looking beyond static 
systemstodynamic systemsthatrespond tochanging climatic 
or occupant conditions. By linking a dimmableelectric light- 
ing system with daylighting controls to a fenestrationsystem 
that can automatically modify the transmission of daylight, 
we can get real-time control of the cooling and
lighting en- 
ergy balance while addressing glare and thermal comfort. We investigated this dynamic systems concept using an au- 
tomated blind system as a substitute for as yet unavailable 
electrochromic "switchable" glazings, working towards an 
occupant-responsivesystem that can be linked to the build- 
ing HVAC system by a network of sensors and operated by 
intelligent energy management controls. The
position of the 
blind system is coupled actively to variable external and in- 
ternal conditions--the sun going behind a cloud or changing 
functional needs in a room, for example. The system accom- 
modatesoccupantpreferences for controlling view,glare,pri- 
vacy,and tasklighting levels when the spaceis occupied,and 
could switchtoaminimum energy consumptionmodewhen- 
ever the occupant left the office.
Our performance evaluation can be found on
page 20. |
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