Dimming for peak demand reduction

Publisher’s version / Version de l'éditeur:

Canadian Facility Management & Design, pp. 12-13, 2010-04-01

READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. https://nrc-publications.canada.ca/eng/copyright

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

Questions? Contact the NRC Publications Archive team at

PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.

NRC Publications Archive

Archives des publications du CNRC

This publication could be one of several versions: author’s original, accepted manuscript or the publisher’s version. / La version de cette publication peut être l’une des suivantes : la version prépublication de l’auteur, la version acceptée du manuscrit ou la version de l’éditeur.

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at

Dimming for peak demand reduction

Young, P.

https://publications-cnrc.canada.ca/fra/droits

L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.

NRC Publications Record / Notice d'Archives des publications de CNRC: https://nrc-publications.canada.ca/eng/view/object/?id=b02da3ff-ba6b-4feb-99e6-4201d4b85887 https://publications-cnrc.canada.ca/fra/voir/objet/?id=b02da3ff-ba6b-4feb-99e6-4201d4b85887

http://www.nrc-cnrc.gc.ca/irc

Dim m ing for pe a k de m a nd re duc t ion

I R C - V I S I - 4 6 2

Y o u n g , P .

A p r i l 2 0 1 0

A version of this document is published in / Une version de ce document se trouve dans:

Canadian Facility Management & Design, pp. 12-13

The material in this document is covered by the provisions of the Copyright Act, by Canadian laws, policies, regulations and international agreements. Such provisions serve to identify the information source and, in specific instances, to prohibit reproduction of materials without written permission. For more information visit http://laws.justice.gc.ca/en/showtdm/cs/C-42

Les renseignements dans ce document sont protégés par la Loi sur le droit d'auteur, par les lois, les politiques et les règlements du Canada et des accords internationaux. Ces dispositions permettent d'identifier la source de l'information et, dans certains cas, d'interdire la copie de documents sans permission écrite. Pour obtenir de plus amples renseignements : http://lois.justice.gc.ca/fr/showtdm/cs/C-42

1 CFM&D April 2010 www.cfmd.ca

M

assive power failures are particularly likely to occur at peak de-mand times, when the margin between the amount of power the grid can supply and the quantity of electricity being consumed is particularly slim. And while it might seem likely that energy demands would be shrinking in these sustainably minded times, that’s not the case, says Guy Newsham, Ph.D., senior research officer with the National Research Council’s Institute for Research in Construction in Ot-tawa. Although there was a blip of a downturn in building energy use in North America in 2009 – attributable in part to an economic crisis and in part to cooler-than-usual summer temperatures – demand was increasing before that and is forecast to continue increasing. And in Ontario, peak de-mand is growing faster than overall energy use. (Peak demand times in Ontario are hot summer afternoons when air conditioning is on at full blast and electric lighting in most of-fices is blazing. In parts of Canada with more severe winters, however, peak demand periods tend to occur when it’s cold outside and the heat has been cranked up within.)

Much of Dr. Newsham’s research has to do with load shifting or load shedding in the corporate and institu-tional sectors, which is to say, shifting the times when a facility’s energy de-mands are highest away from the gen-eral peak demand spike (through strategies such as using a building’s

thermal mass for heating and cooling), or reducing the amount of energy a facility is consuming at peak demand periods. Late last year at the Construct Canada conference in Toronto, Dr. Newsham shared some of his findings in the latter area in a compelling pres-entation titled “Making Buildings Re-sponsive to Peak Energy Demand: Saving the grid without affecting pro-ductivity.” In essence the results indi-cate that people in offices or

educational environments not only tolerate but in most cases do not even notice significant light dimming or in-creases in temperature of up to 1.5º C, provided that these changes occur smoothly and gradually.

In one of the National Research Council (NRC) studies discussed, par-ticipants spent a day completing ques-tionnaires and standard office tasks in a full-scale office laboratory environ-ment illuminated by direct-indirect

BY PAMELA YOUNG

DIMMING FOR PEAK DEMAND REDUCTION

National Research Council studies indicate that temporarily dimming lighting could be a viable means of achieving peak demand reduction

[

energy update

]

❯

The two graphs above represent the mean fraction of occasions that a change in lighting was noticed (left) or acceptable (right), by size of reduction from baseline, and amount of prevailing daylight. ND = non-daylit. LD = below median prevailing daylight. HD = above median prevailing daylight. Open sysmbols indicate fractions that did not differ significantly from the no-change case (0 pe cent reduction) for that daylight condition; closed symbols indicate a significant difference.

❯

This graph relates to the research studies conducted in a federal office building. It shows total power drawn by the lighting system in the building study zones, and two sample interior illuminance measurements, for one load shed trial enacted in the afternoon.

luminaires using 3500K T8 fluorescent lamps. A control group experienced constant lighting and ventilation con-ditions. Through the use of dimming controls, a second group experienced a reduction in workstation illuminance of 2 per cent per minute over a 30-minute period. This sec-ond group also experienced an ambient air temperature in-crease of 1.5º C over 2.5 hours. Participants were not told that these changes would occur. While some in the second group did perceive a change, they did not rate their ‘envi-ronmental satisfaction’ lower during the period of higher temperatures and diminished lighting levels, and it did not seem to affect their performance of tasks such as typing and anagram solving.

A third group had personal dimming control over light-ing at their workstations, along with the ability to adjust ventilation rate via an overhead nozzle. Results showed that 20 per cent of the participants had chosen to increase light levels by the time that desktop illuminance had declined approximately 35 per cent from their initial preferred level, and 50 per cent of the participants took action to raise their lighting levels when desktop illuminance had declined by approximately 50 per cent.

In a second laboratory study, participants in an office laboratory received a baseline desktop electric lighting level of 400 lux. The lighting was dimmed smoothly over a 10-second period. During the dim, and for 30 seconds afterwards, participants performed a computer-based proofreading task. They were asked whether they noticed a change in lighting, and whether the lighting conditions were acceptable. The exercise was repeated over multiple trials, with dimming intensity varying from zero to 80 per cent, in settings with or without daylight. And the results? “The level of dimming not noticed by occupants was 20 per cent with no daylight, 40 per cent with relatively low prevailing daylight, and 60 per cent with high prevailing daylight,” the study concluded. Furthermore, participants rated the lighting levels “acceptable” when a 40 per cent dimming occurred when little or no daylight was pres-ent, and when an 80 per cent dimming occurred with high prevailing daylight.

In a subsequent field study in a federal office building, lights were dimmed by up to 35 per cent over periods of 15 to 30 minutes, achieving a power reduction of just over 5 kW (23 per cent lower than pre-test power demand lev-els) – and there were no lighting-related complaints.

“From these studies,” Dr. Newsham concluded, “one can begin to develop guidelines for demand-responsive dim-ming that could be included in recommended practice doc-uments or standards for office lighting, and referenced in utility demand response programs.” Even in spaces with no daylight, these studies suggest, a rapid-response dimming of 20 per cent could occur over as short a time as 10 seconds without the large majority of the occupants noticing the change. A slow response, conducted over 30 minutes or more, could reduce lighting by as much as 30 per cent in spaces with no daylight, once again without detection by the majority of the occupants. In spaces with high prevail-ing daylight, a dimmprevail-ing of up to 60 per cent could be

achieved without being noticed by most occupants. “Dimming lighting is something that could be done when the demand [for electricity] is really close to exceed-ing the supply,” Dr. Newsham observed. He added, how-ever, that the absence of dimming technology in most office buildings is an obstacle: although approximately two-thirds of LEED®_{-certified projects incorporate lighting} control systems, these systems are installed in only about seven per cent of all U.S. office space. “I wouldn’t expect anybody to install dimming systems just for the purposes of demand response,” Dr. Newsham said. “You’d install a dim-ming system to save energy through daylight harvesting and occupancy sensing. But once you have a system in place, being able to participate in demand response programs could be the icing on the cake.”

He also cautioned that bringing lighting down and cut-ting back on air conditioning on hot summer afternoons are “temporary measures to be used in extreme circum-stances” and should not become the new normal. “Under normal circumstances I think lighting systems should pro-vide conditions that people prefer, not just what they’ll tol-erate,” he said. “There’s lots of evidence to suggest that the preferred average levels are what we would consider typi-cal normal recommended practice.” Extensive informa-tion about the research projects discussed here and other NRC Institute for Research in Construction studies is posted at http://www.nrc-cnrc.gc.ca/eng/projects/irc/de-mand-responsive.html. | CFM&D

Canadian Facility Management & Design April 2010 CFM&D 13

G R A P H S : D R . G U Y N E W S H A M I]ZGZigdEaViZHnhiZb]VhWZZc`Zn ^c VX]^Zk^c\ A::9 gZXd\c^i^dc [dg bVcn egd_ZXih! bdhi gZXZcian 7gdX` Jc^kZgh^in VcY I]Z 8Va\Vgn 8]^aY 9ZkZadebZci8ZciZg#6hVcVaiZgcViZ

id igVY^i^dcVa [addg XdkZg^c\h i]Z GZigdEaViZ hnhiZb ijgch WVgZ XdcXgZiZ^cidVcVWgVh^dcgZh^hiVcihjg[VXZi]Vi^hZVhnidXaZVcVcY ]VhVbVgWaZ"a^`Zh]^cZ#

Cdi dcan ^h GZigdEaViZ a^hiZY Vh V '%%+ Ide"&% <gZZc 7j^aY^c\ EgdYjXi!Wji^bbZY^ViZZcZg\nhVk^c\hXVcWZgZVa^oZY^ca^\]i^c\ VcYbV^ciZcVcXZ#

<d^c\<gZZcl^i]

Eda^h]ZY8dcXgZiZ;addgh

Feb_i^[Z9edYh[j[<beehi <beehH[celWbiFh[f$ ;feno9eWj_d]i 2006 Top-10 Green Building Product

GreenSpec™ LISTED www.BuildingGreen.com

($///$.*/$--'-nnn%Ye\ZfekiXZkfij%Zfd

86C69>6CB;<G:E# lll#gZigdeaViZhnhiZbh#XV &"-%%"-)&"*+,,                     GZi ^h dcan Cdi ]VhVbVgWaZ"a^`  

XdcXgZiZ^cidVcigVY^i^dcVa[ad        

id 8Z  9ZkZadebZciVcY Jc^kZgh^inegd_ZXih! bVcnVX]^Zk^c\A:  ^c GZigdEaViZH  I]Z   a^hiZYVhV'%%+Ide"&% gdEaViZ     VWgVh^dcgZh^hiVcihjg[VXZi]Vi^hZV  Zh]^cZ# hnhi  GZigdEaViZ i]Z XdkZg^c\h ddg 6hVcVaiZgcViZ ZciZg#I]Z 8Va\Vgn 8]^aY 7gdX` gZXZcian bdhigZXd\c^i^dc[dg ::9HnhiZb]VhWZZc`Zn     <gZZc7j^aY^c\ VcVcY         VhnidXaZZbijgchWVgZ     VcYbV^ciZcVcXZ!Wji^bb  EgdYjXin    

/$--'- Z#bZY^ViZZcZg\nhVk^c\hXVcWZgZV  e 

*

.

($///$

&"-%%"-)&"*+,, lll#gZigdeaViZhnhiZbh#XV 86C69>6CB;<G:E#     a^\]i^c\ ^c a^oZY \ .BuildingGreen.com www LISTED ™ GreenSpec

Green Building Product op-10 2006 T Top-10    

n

   

fd

Z

%

j

fi

XZk

feki

%Ye\Z

nnn

n%

( ///

.

*

/

--'-   

d