Distributing admitteddaylightflux posesacriticaltechnicalprob-
lem.Spreading daylight evenly to attaina functional and com-
fortable lighting environment for a wide range of sun positions
and sky typesrequires ingenuity.

Wedesigned prototype lightshelves, lightpipes, and skylights to
1) extend the daylighted area of the perimeter zone of buildings
from approximately 15 ft to 30 ft (5 to 10 m), and 2) to provide
more brightness in the back of typicalspaceswithout the associ-
ated high light levels near the windows. While the research was
devoted to solving the optics problem of redirection with a vari-
able sun source without introducing direct sun or creating glare,
we also restricted the window aperture size to minimize solar
heat gains. Prototypes were developed, simulatedand tested in
scale-model rooms,both outdoorsandwithin indoor simulators.
Both light-redirectingsystems were designed without moving
parts to reduce costs and maintenance. A full-scale demonstra-
tion of the skylight design at thePalm Springs Chamber of Com-
merce (discussed later) enabled us to solve critical fabrication
issues and to evaluate the final daylit environment.

Our reduced-scaletesting revealed the potential for substantial
energy savings with improved lighting quality.Hourly DOE-2
simulations predicted annual energ y savings of 10-20% with
improved lighting quality compared to a clear glazed window
(no interior shades)with daylighting controls. Performancewas
bestfor sun azimuthangles thatwere within ±45șof thewindow's
outwardsurfacenormal,but aside reflector geometry improved
performance for more obtuse surface solar azimuth angles.Al-
though their benefitis greatestin sunny climates,we believe these
systems show enough promise to pursue further development
and testing activities.