Ecobuild 2014: Daylight
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Transcript of Ecobuild 2014: Daylight
Median Daylight Availability
• The amount of daylight that is available for half of the time.
• For London 14,100 lux
General Requirements
• DF – 2% start of daylight appearance• DF – 5% daylight provides nearly all of the
light needed
• Median Daylight Illuminance 300 lx
Energy Savings
• Key factors– Daylight availability– Daylight penetration – Lighting control system– User satisfaction
Background
Küller, R.; Lindsten, C. (1992). Health and behaviour of children in classrooms with and without windows. J. Environ. Psychol. 12, 305-317
Showed:• Children in classrooms with daylight show
different annual variation in levels of cortisol
Background
Hershong, L., Wright, RL. and Okura, S. (2002). Daylighting impacts on human performance in school. Journal
of the Illuminating Engineering Society Showed:• significant effects of daylighting on the
performance of school students
Background
Govén, T., Laike, T., Pendse and B. Sjöberg, K. (2007). The background luminance and colour temperatures influence on alertness and mental health. CIE 26 Beijing
Showed:• ambient light is of upmost importance
Key Points of the Study
• 4 form entry primary school (~120 pupils per year)
• Pupils age 7 to 8• Test of impact of light (natural and electric)• Variety of pupil impact measures• Year long study
Study DatesMain Dates Supplemental Dates
8th October 2008 5th November 2008
9th December 2008 14th January 2009
10th February 2009 4th March 2009
25th March 2009 29th April 2009
20th May 2009 10th June 2009
Dates of data collection
Study ActivitiesTimes Operations
08:00-08:50 Preparations
08:50 The start of school day – Subjective sleep quality reports*
09:50 Subjective mood and sleepiness reports & Saliva samples*
10:15-10:30 Morning break
11:45 Subjective mood and sleepiness reports + Saliva samples
12:00-13:10 Lunch break
14:45 Subjective mood and sleepiness reports + Saliva samples
15:20 The end of School day
Daily routine for the main collection days* Supplemental collection days
Pupils in the Study
Pupil Numbers
Classrooms
Total
C1 E1 E2 C2
The number of participating pupils 14/30 11/29 16/29 15/29 56/117
The number of participating male pupils 7/15 7/14 9/14 7/15 30/58
The number of participating female pupils
7/15 4/15 7/15 8/14 26/59
The number of pupils in the study
Overall Avarage Mood Scores
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
08 Oct. 09 Dec. 10 Feb. 25 Mar. 20 May.
Date
C1
C2
E1
E2
Overall Avarage Mood Scores
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
08 Oct. 09 Dec. 10 Feb. 25 Mar. 20 May.
Date
DF ~2%
DF ~5%
The analysis of the monthly trend of the cortisol levels at 09.50 revealed a significant difference between months contrast (F(1,22)=8,087, p=.009) and a significant difference between the rooms (F(1,22)=4,969, p=.036)
Findings OverviewAnalysis is being finalised a paper in LR&T should be
published later this yearGeneral findings:• The pupils with more daylight did better than those
with less• In the rooms with less daylight the higher level of
electric light helped during the winter• In rooms with more daylight extra electric light
made no difference