EXPERIMENTS IN ENERGY OLYMPICSWEST OF ENGLAND CARBON CHALLENGE 2012-11-07, 1600 Sukumar Natarajan with contributions from Julian Padget, Ian Walker and Teresa Chiang, Nadya Dara, Gokhan Mevlevioglu
Energy Use /Climate Efﬁciency / BuildingChange Security DesignEnergy and the Design of Environments (EDEn) ENergy Literacy COPSE / through an Prometheus IntelligenT home (both using ENergy advisor UKCP09 data) (ENLITEN)
CONTEXT• Domestic: • Users have control over decisions • Relatively easy to connect cause and effect• Non domestic: • Users generally have less control • More tricky to connect cause and effect
Question 1: Does (the type of)feedback affect energy consumption?Savings from various studies range from 0% to 22%Larger and longer term trials show less than 5% savings from controlThree types of displays were proposed in the literatureExperiment 1: laboratory testExperiment 2: live (student residence)
convey information. Th tion simultaneously in a direct and intuitive manner . Anderson inclusion of human face and White  found through working with focus groups that the know Human faces are design of a speedometer dial was particularly preferred even when reduced to for its qual- ities of eye-catching movement, intuitive scale and direction of and biol to their social be processed differently change, and ease of making comparisons. It will be interesting to and mor detected faster see if similar preferences are seen in this study. Question 1: Does (the type of) Fig. 1. Numerical display . The intention of this w Ambient displays (Fig. 3) provide an overall indication of a situa- capturing property mak tion, sometimes make use of peripheral vision, and do displays. Speciﬁcally, th not require like faces. users’ detailed attention [8,22]. No text or numbers are shown; feedback affect energy consumption? instead, pictures, colours, sounds or ﬂashing lights are used to 2.2.2. Colour convey information. The present work attempts to introduce theA large number of inclusion of human faces in the design of user interface prototypes. and screen design hav ARTICLE IN PRESS Human faces are known to have the capacity to attract attention, attentioG Model and directionalENB-3818; No. of Pages 10 colour, size, orientation even when reduced to cartoon form [26,27]. Presumably thankssearch or when people T. Chiang et al. / Energy and Buildings xxx (2012) xxx–xxx 3 to their social and biological signiﬁcance, human faces seem to have th been found to be processed differently by the human brain: changes stimuli due to its highlig in faces are Analogue displays (e.g. Fig. 2) illustrate the scale of consump- tion usually without numbers, using graphs, charts, dials, column detected faster and more accurately than in other objects [e.g. 28].target stim rate potential also help to shorten se gauges and bars. ComparedFig. 1. Numerical display . often to numerical displays, these are The intention of this work is to ﬁnd out if the face’s attention [after 5]. As colour is Fig. 2. Analogue display . considered easier to read and interpret, especially when making capturing property makes it a useful cue in the design of energy colour c processing of comparisons, e.g. between current and target values . Ana- amounts of cognitive c displays. Speciﬁcally, the study looked at two-dimensional cartoon- ☺ logue displays can be effective in checking readings, evaluating the present work also future states and conveying quantitative and qualitative informa- like faces. (i.e. non black-on-white tion simultaneously in a direct and intuitive manner . Anderson display designs (details and White  found through working with focus groups that the 3.2). design of a speedometer dial was particularly preferred for its qual- 2.2.2. Colour ities of eye-catching movement, intuitive scale and direction of A large number of studies [e.g. 32–34] on web pageUsers’ preferences design 2.3. change, and ease of making comparisons. It will be interesting to and screen design have shown that comprehension, distraction see if similar preferences are seen in this study. Ambient displays (Fig. 3) provide an overall indication of a situa- and directional attention are heavily inﬂuenced by the Previous research ha location, tion, sometimes make use of peripheral vision, and do not require colour, size, orientation, shape and luminance of targetstion people preferred to [e.g. 35,36] could help to serve pre users’ detailed attention [8,22]. No text or numbers are shown; when people search or read displays. Colour, in particular,designed two t the USA has instead, pictures, colours, sounds or ﬂashing lights are used to convey information. The present work attempts to introduce the been found to have the capacity to attract attention to targetbar graph consumption: distribution graphic des stimuli due to its highlighting and association effects, and to sepa- inclusion of human faces in the design of user interface prototypes. bourhood mapped on a Human faces are known to have the capacity to attract attention, rate potential target stimuli from non-target stimuli . It might consumption . This even when reduced to cartoon form [26,27]. Presumably thanks also help to shorten search time more than shapes or numbers concepthe same design to their social and biological signiﬁcance, human faces seem to be processed differently by the human brain: display . Fig. 2. Analogue changes in faces are [after 5]. As colour is a basic . Fig. 3. Ambient design element of visual perception, and difﬁcult t “childish” the detected faster and more accurately than in other objects [e.g. 28]. processing of colour coded information does not require large easy to comprehend due to the consistent exposure in a number digital Fig. 1. Numerical display . analogue The intention of this work is to ﬁnd out if the face’s attention capturing property makes it a useful cue in the design of energy displays. Speciﬁcally, the study looked at two-dimensional cartoon- ambient of activities both at home (kitchen timer, [after clock, TV, For these reasons, amounts of cognitive capacities alarm 38,39]. etc.) 7 The present work studie the present work also investigates the effectiveness of coloured studies ha and work (security systems, vending machines, etc.). The present design, as previous work intends to examine presenting energy informationagainst black-on-whitein better pe (i.e. non black-on-white7 ) display designs with pure polarity) resulted like faces. numbers. (negative polarity) [56,57]. display designs (details of the experiment are described in Section detailed 2.2.2. Colour illustrate 3.2). provide an Please cite this article in press as: T. Chiang, et al., A laboratory test of the efﬁcacy of energy d quantitative scale of A large number of studies [e.g. 32–34] on web page design and screen design have shown that comprehension, distraction “indication” (2012), http://dx.doi.org/10.1016/j.enbuild.2012.07.026 information consumption and directional attention are heavily inﬂuenced by the location, colour, size, orientation, shape and luminance of targets [e.g. 35,36] 2.3. of the situation Users’ preferences when people search or read displays. Colour, in particular, has been found to have the capacity to attract attention to target Previous research has shown mixed ﬁndings on what informa- stimuli due to its highlighting and association effects, and to sepa- tion people preferred to receive and which type of graphical design rate potential target stimuli from non-target stimuli . It might could help to serve presenting information better. Researchers in also help to shorten search time more than shapes or numbers [after 5]. As colour is a basic element of visual perception, the the USA designed two types of graphical displays to show energy we wanted to control these quite carefully, so COTS were not an option Fig. 2. Analogue display . processing of colour coded information does not require large consumption: bar graphs and distribution graphs. Fig. 4 is one of the amounts of cognitive capacities [after 38,39]. For these reasons, distribution graphic designs that displayed little houses in a neigh- the present work also investigates the effectiveness of coloured bourhood mapped on an x–y axis graph according to their energy (i.e. non black-on-white7 ) display designs against black-on-white display designs (details of the experiment are described in Section consumption . This design was ranked most preferred, while 3.2). the same design concept presented in Norway  was judged as Fig. 3. Ambient design . “childish” and difﬁcult to interpret. 2.3. Users’ preferences easy to comprehend due to the consistent exposure in a number Previous research has shown mixed ﬁndings on what informa- of activities both at home (kitchen timer, alarm clock, TV, etc.) tion people preferred to receive and which type of graphical design 7 The present work studied black-on-white design instead of white-on-black could help to serve presenting information better. Researchersetc.). The present and work (security systems, vending machines, in design, as previous studies have shown that dark text on light background (positive
Experiment 1: The key question isHow good are we at detecting change in information: speed and accuracy
Fig. 9. Mean accuracy rates. Fig. 9. Mean accuracy rates.mage (bottom). dium, high, which were UK household’s annualottom).splay design had a black-ersion (Fig. 7). The overall high, which wereas white. Red and greenousehold’s annualeir associative meanings, Fig. 10. Mean response times.ranges,had a black- and esign respectively,
mages used the samehe design changed ran- The interviews were semi-structured, such that discussiond Test images differed stemmed from the core questions. In many instances, more thane display components.ickly and accurately asanging display compo-o ensure that the timese was minimised, the e “@” key (next to the “Today so far” and “Yester-rage electricity consumption average daily consumptionhe full range and divided by0–6 kWh, the medium range1 kWh and higher. It is worth G Model ENB-3818; No. of Pages 10 ARTICLE IN PRESSximations appropriate to the bt be different, these are not 8 T. Chiang et al. / Energy and Buildings xxx (2012) xxx–xxxnts were focused on changes Table 3 Fig. 11. Display design preferences. backgrounds as possi Summary of response time and accuracy. pants had undertaken Response time Correct Preference that the participantsng, et al., A laboratory test of the efﬁcacy of energy display interface design, Energy Buildings or higher, and theref Design typea Ang > Amb = Nmr Nmr = Amb > Ang Nmr > Amb = Angd.2012.07.026 Colourb B/W = Clr B/W = Clr Amb > Ang = Nmr ulation at large. Furth Amb B/W > Amb Clr rule out a correlation a Amb: ambient, Ang: analogue, Nmr: numerical. performance. b B/W: black-on-white, Clr: colour. (b) Lab based experiment: > means signiﬁcantly greater than, = means marginally different. “laboratory condition capture perception in by removing the dist found that if users ﬁnd the product features similar to their previ- in their domestic env ous experience, they are more likely to perform tasks better [51,52]. study provided a usefu
Experiment 2: The key question is How good are we at reducing energy whenpresented the same information in different ways?
Westwood Residences Eastwood Nursery Residences Eastwood Offices 20/21 22/23 P K P J se ou xH P L se es W W sear Park ou dH Bale Marlborough oo Haus Court rw No urt rt Woodland Co 6W S Solsbury Cou PE East Car Park East buildingD 3S A nne xe 4S Ann ex e Student residences with good wiﬁ access, 4 x kitchens per ﬂoor P C P B EachC“kitchen group” was sub-metered by lights and small power P P A Recyc li Kitchens comparable to each other with 7 students per group ng P G 6 kitchens were selected, 2 each on ﬂoors 7, 8 and 9 2 non-participating groups were used as control Baseline period for comparison was the average over a period of days a immediately before the start of the experiment Outdoor Tennis Courts
Cumulative consumption Total Cumulative from 00:01 to time of consumption from update (say 09:00) 00:01 to 00:00 colour blind safeAverage daily Average dailyconsumption consumption last this week week
Group A B C D E F 1-2Weeks 3-4 5-6 “Winner takes it all” £20 per member of the group that reduced the most over 6 weeks
Conﬁdence intervals for the experiment groups did not include zero change, so these results are signiﬁcant at the 0.05 level. Plainspeak: there is a 95% probability that these results did not occur due to pure chanceParticipants preferred this the most, yet Conﬁdence intervals for the control groupsambient seems to perform better! did include zero change. Plainspeak: the change for these groups from baseline are not reliably different from zero
Question 2: Is competitive ranking enough, on its own, to deliver savings? In the previous experiment, groups were competing against absolute savings However, this tends to favour groups starting from a low baseline We wanted to test if comparing against one’s own savings would be different Further, this time every person stood to gain ﬁnancially as rewards were calculated using an arbitrary ﬁxed rate (35p) per kWh saved cumulatively compared to the baseline period.
Experiment 3: The key question isHow good are we at reducing energy when comparing our performance against the performance of others?
Mean change in consumption (kWh) compared to baseline
Questions 3 & 4: Will any of these ideas work in an ofﬁce environment? Do rewards matter? Applied the idea of self-relative ranking from previous experiment to BH ofﬁces Information was separated by lighting and small power Instead of monetary units, performance was measured in “meters run” Provide additional context to ranking information Test if rewards are essential and if (any) savings persist over time. Information on how to save was given before the start of the competition Environmental attitudes were measured before and after the competition Due to technical problems experiment ran for 5 weeks instead of 6
Therefore, the percentage of energy for heating would probably increase. For example, Figure 3.2.3 illustrates the difference in percentage of energy subsectors in June and April, where it is clear that heating is the first largest consumer in April whereas in June Proportion of total energy consumption in both buildings by end-use small power consumes over a half of all energy. 60.00% 50.00% 40.00% 30.00% June April 20.00% 10.00% 0.00% Small Lighting Canteen Lift Server Printers Heating power room room Figure 3.2.3. Comparison of total Buildings energy consumption by sectors in June and April. 40/141
Equivalent of “net earnings” in the previous study The effectiveness of behavioural interventions to reduce office energy consumption Figure 3.4.1. Scheme of display screens. Provide context on “how far Lighting away” other groups are Computer Weekday Weekend Nominal Weekday Weekend Nominal Floor Floor average average Average average average Average
Mean percentage savings and ranges 0%% reduction from baseline 10% 20% 30% Lighting Computers Total
% savings from baselineafter one week -40% -27% -13% 0% 13% 27% 14/07/2012 22/07/2012 29/07/2012 05/08/2012 12/08/2012The ﬁrst data point is the average saving 19/08/2012 End of period 26/08/2012 Computer Use 02/09/2012 competition 09/09/2012 16/09/2012 23/09/2012 30/09/2012 Lighting 07/10/2012 Tablets 14/10/2012 Removed 21/10/2012 28/10/2012 Average savings over all groups split by end-use
general level of the awareness has not changed much. Q1. I am an environmentally aware person interventions The effectiveness of behavioural to reduce office energy consumption 50.00% However, questions about humans’ rights and abilities to prevent the destruction of the 45.00% 40.00% Earth (3, 5, 7) in both buildings were more optimistic than in the previous questionnaires 35.00% and the percentage of ‘agree’ answers was by 8-12% higher. 30.00% 25.00% 4.3.2. Behavioural change. before competition 20.00% 15.00% after competition Interestingly, the answers about behavioural actions performed by occupants have 10.00% significantly improved in both buildings by an average 15.6% (Figure 4.3.2, Appendix P, 5.00% 0.00% Table P2). The most significant was improvement in turning off lights overnight by 50.25% 1 2 3 4 5 6 7 on the Ground floor of the Building 1 and switching off monitors on the Second floor of the (Strongly (Strongly Building disagree)grew from 25% to 71% and the use of ‘sleep’ mode that increased form 2 that agree) 33% to 71%. Figure 4.3.1. Comparison of responses before and after the competition on Question 1. 120.00%In Building 1 on the Ground and First floors the amount of positive responses was lower by 100.00% whereas on the winning floor (the Second) the amount of positive answers 3-5%, Building 2reached 100%, higher by 18.75% than before the competition (Appendix P, Table P2). 80.00% before Building 2In Building 2 the change is slightly more significant (Appendix P, Table P2). On the First after 60.00%and the Third floors awareness was higher by about 25%, whereas on the Second floor it Building 1 beforewas lower by 14%. 40.00% Building 1 afterThe questions that represent environmental attitude (2, 4, 6, 8) in general received slightly 20.00%less positive response from both buildings (Appendix P, Table P2). However, for the 0.00%Second Floor of Building 1 (winner) some questions were answered more positively, such 9. adjust 10. swtich off 11. turn off 12. use 13. switch offas Question 4 lights36%) and Question 6 (by 21%) whereas other questions (2, 8) were (by comp lights sleep mode monitor about the same level. Figure 4.3.2. The comparison of positive responses about ecological behaviour.
ANSWERS• Simplyputting something in place seems to have an effect• We need to be wary, however, of the Hawthorne effect• What people say and what they do don’t always match• Some designs may be better than othersWHAT WE DON’T KNOW• How do hybrid designs perform?• Are these savings sustained? How can we make them habitual?• What is an appropriate baseline measure?• Are rewards essential? Need they be monetary?
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