Electric lighting energy savings for an on/off photocell control – a
comparative simulation study using DOE2.1 and DAYSIM
Reinhart, C.; Jones, C.
NRCC-46761
A version of this document is published in / Une version de ce document se trouve dans :
Proceedings of eSim 2004, Vancouver, B.C., June 10-11, 2004, pp. 183-189
http://irc.nrc-cnrc.gc.ca/ircpubs
ELECTRIC LIGHTING ENERGY SAVINGS FOR AN ON/OFF PHOTOCELL
CONTROL – A COMPARATIVE SIMULATION STUDY USING DOE2.1 AND DAYSIM
Christoph F. Reinhart
The Lighting Group - Institute for Research in Construction
National Research Council Canada, Ottawa K1A 0R6, Canada
christoph.reinhart@nrc-cnrc.gc.ca
Christopher Jones
EnerSys Analytics Inc.
Toronto, Ont., M5J 2E6, Canada
cj@cr-jay.ca
ABSTRACT
This paper suggests a method how to predict electric
lighting energy savings for photocell controls in daylit
spaces taking manual blind control into account. The
method predicts lower but supposedly more “realistic”
lighting energy savings than conventional simulation
approaches. On the other hand, predicted savings are
larger than those predicted by ASHRAE 90.1 power
adjustment factors. The method is demonstrated in a
hypothetical open plan office in Calgary, Canada. A
comparative simulation study is presented using DOE.2
and the RADIANCE-based daylighting analysis tool
DAYSIM. Simulation results were found to differ
substantially between DOE2 and DAYSIM even in the
absence of venetian blinds. These discrepancies were
attributed to the underlying simulation algorithms and
sky models. Despite these differences, both simulation
programs yielded energy savings more than twice the
static 10% allowed for by ASHRAE 90.1 power
adjustment factors for on/off control.
INTRODUCTION
Daylight has been identified by Pacific Gas & Electric
as “the single largest ´new´ opportunity for saving
energy in commercial lighting today” (Turnbull and
Loisos 2000). On the o