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Le dtalk cde bakker_final 2015-11-10
- 1. Rethinking occupancy-based office lighting ir. Christel de Bakker Building Lighting group Technische Universiteit Eindhoven
- 2. Introduction Definition of occupancy-based office lighting Rethinking occupancy-based office lighting – Christel de Bakker2
- 3. Introduction Topic 3 • Occupancy-based lighting control on floor level Rethinking occupancy-based office lighting – Christel de Bakker
- 4. Introduction Topic 4 • Occupancy-based lighting control on desk level Rethinking occupancy-based office lighting – Christel de Bakker
- 5. 5 Rethinking occupancy-based office lighting – Christel de Bakker Goal Current state of research Studies Vision
- 6. Introduction Study object Rethinking occupancy-based office lighting – Christel de Bakker6 Open-plan & flexible workspaces Smart LED connected lighting system
- 7. Introduction Study object Rethinking occupancy-based office lighting – Christel de Bakker7 = optimal use of lighting & space Occupancy Illuminance CO2 Temperature + location of desk/zone Relative humidity
- 8. Rethinking occupancy-based office lighting – Christel de Bakker8 Current lighting control strategy Per zone
- 9. Rethinking occupancy-based office lighting – Christel de Bakker9 Current lighting control strategy Per zone
- 10. Rethinking occupancy-based office lighting – Christel de Bakker10 Current lighting control strategy Independent of individual occupant behaviour
- 11. Rethinking occupancy-based office lighting – Christel de Bakker11 Current lighting control strategy Independent of individual occupant behaviour
- 12. Rethinking occupancy-based office lighting – Christel de Bakker12 Current lighting control strategy Independent of individual occupant behaviour
- 13. Rethinking occupancy-based office lighting – Christel de Bakker13 Current lighting control strategy Independent of individual occupant behaviour Chang, W. K., & Hong, T. (2013, March). Statistical analysis and modeling of occupancy patterns in open-plan offices using measured lighting-switch data. In Building Simulation (Vol. 6, No. 1, pp. 23- 32). Tsinghua Press.12:00 13:00 • Different occupancy patterns
- 14. Rethinking occupancy-based office lighting – Christel de Bakker14 Current lighting control strategy Independent of individual occupant behaviour Maleetipwan-Mattsson, P., & Laike, T. (2015). Optimal office lighting use: a Swedish case study. Facilities, 33(9/10). 7:14 15:44 9:48 12:00 13:00 17:42 • Different arrival and departure times
- 15. Rethinking occupancy-based office lighting – Christel de Bakker15 Current lighting control strategy Independent of individual occupant behaviour • Non-optimal lighting use 7:14 17:42
- 16. Rethinking occupancy-based office lighting – Christel de Bakker16 Main research question How can occupancy-based lighting be optimally used in open-plan offices?
- 17. Rethinking occupancy-based office lighting – Christel de Bakker17 Current state of research Energy savings in private offices Von Neida, B., Manicria, D., & Tweed, A. (2001). An analysis of the energy and cost savings potential of occupancy sensors for commercial lighting systems. Journal of the Illuminating Engineering Society, 30(2), 111-125. 5 min10 min15 min20 min • Baseline: no occupancy sensor • Savings during day-time62% 73%
- 18. Current state of research Open-plan offices? Rethinking occupancy-based office lighting – Christel de Bakker18 + comfort of co-workers
- 19. Rethinking occupancy-based office lighting – Christel de Bakker19 • Individual characteristics Chang, W. K., & Hong, T. (2013, March). Statistical analysis and modeling of occupancy patterns in open-plan offices using measured lighting-switch data. In Building Simulation (Vol. 6, No. 1, pp. 23- 32). Tsinghua Press. Studies 1. Reveal individual occupancy patterns and their underlying factors
- 20. Rethinking occupancy-based office lighting – Christel de Bakker20 • Spatial characteristics Chang, W. K., & Hong, T. (2013, March). Statistical analysis and modeling of occupancy patterns in open-plan offices using measured lighting-switch data. In Building Simulation (Vol. 6, No. 1, pp. 23- 32). Tsinghua Press. Studies 1. Reveal individual occupancy patterns and their underlying factors
- 21. Rethinking occupancy-based office lighting – Christel de Bakker21 • Time characteristics Bouffaron, P. (2014). Revealing Occupancy Diversity Factors in Buildings Using Sensor Data Studies 1. Reveal individual occupancy patterns and their underlying factors
- 22. Studies 1. Reveal individual occupancy patterns and their underlying factors Rethinking occupancy-based office lighting – Christel de Bakker22 • Restrictions
- 23. Studies 2. Develop spatial clustering methods Rethinking occupancy-based office lighting – Christel de Bakker23 • Occupancy profiles
- 24. Studies 2. Develop spatial clustering methods Rethinking occupancy-based office lighting – Christel de Bakker24 • Lighting preferences e.g. illuminance level
- 25. Studies 2. Develop spatial clustering methods and create acceptance Rethinking occupancy-based office lighting – Christel de Bakker25 • Workspace preferences
- 26. Rethinking occupancy-based office lighting – Christel de Bakker26 Studies 3. Development of occupancy-based lighting control strategies tailored to open-plan office Control characteristics e.g. time delay setting, dimming level
- 27. Studies 4. Occupancy lighting control strategies tailored to individual worker within cluster Rethinking occupancy-based office lighting – Christel de Bakker27
- 28. Rethinking occupancy-based office lighting – Christel de Bakker28 Studies 4. Occupancy lighting control strategies tailored to individual worker within cluster Garg, V., & Bansal, N. K. (2000). Smart occupancy sensors to reduce energy consumption. Energy and Buildings, 32(1), 81-87. typical workday inactivity period
- 29. Rethinking occupancy-based office lighting – Christel de Bakker29 Studies 4. Occupancy lighting control strategies tailored to individual worker within cluster 71 sec54 sec39 sec17 sec inactivity period Garg, V., & Bansal, N. K. (2000). Smart occupancy sensors to reduce energy consumption. Energy and Buildings, 32(1), 81-87. typical workday inactivity period
- 30. Aim Optimal lighting use & comfort Rethinking occupancy-based office lighting – Christel de Bakker30 lighting = occupancy comfort of worker & co-workers
- 31. Rethinking occupancy-based office lighting ir. Christel de Bakker Building Lighting group Technische Universiteit Eindhoven Thank you for your attention! Any questions?
Editor's Notes
- My name is Christel de Bakker. From the 1st of September I joined the Building Lighting group as a PhD. I have a mixed background: I did my bachelors in the Built Environment and graduated this summer at Human Technology Interaction, here at Eindhoven University of Technology. The topic of my presentation is occupancy-based office lighting as I will investigate how lighting can be tailored more precise to occupancy patterns in open-plan offices.
- So what do I mean with occupancy-based office lighting? The principle is quite simple. If nobody is present in the office lighting is switched off. As soon as someone enters the office lighting is switched on.
- Why do I want to study particularly open-plan offices? Well, lighting is controlled far from optimal here. We see either this occuring, where the lighting is controlled for a complete floor,
- Or this scenario, the other extreme, where the lighting is controlled based on individual occupancy.
- I want to find the right midway in my PhD. As I just started (1st of September) the outline of this presentation will be quite different from the other presentations you have attended and will attend today. I will discuss the problem I see occurring today with occupancy-based lighting control strategies in open-plan offices. I will explain the current state of research around this topic. Besides I will tell you about some of the studies I am planning to do and how these lead to the goal I want to accomplish with my PhD.
- I have the opportunity to do my studies in the smartest building of the world, the Edge, the office building of Deloitte in Amsterdam. Here employees are allowed to choose where they want to work. They are not bounded to the physical office and can also work from home for example. Therefore there are only 1000 desks while 2300 employees work at this location. Nobody has consequently his or her own desk: they have to search for a desk every day. Philips installed here an intelligent LED lighting system.
- This system incorporates five sensors measuring motion, illuminance, CO2, temperature, and humidity. This provides us with a lot of data about the occupants’ behaviour and consequently with the opportunity to learn how the space is used. I am going to exploit this opportunity in my PhD to tailor the lighting to the actual use.
- Currently the lighting in the Edge is controlled per zone, which typically involves four desks.
- A motion sensor is placed above each two desks. These communicate to all four luminaires.
- This means that if the motion sensor measures occupancy at one of those two desks, all four luminaires are switched on.
- And similarly, if the other motion sensor measures occupancy at one of those two desks, all four luminaires are also switched on.
- It also means that either one or three desks are occupied, the same lighting scenario is applied. Lighting is thus used also where it is not needed, which means that energy is wasted.
- It becomes even worse when the occupants of those four desks have very different occupancy patterns. Chang and Hong found five typical patterns, among which these two. The first occupant stays at his or her desk the whole day while the second goes for a lunch break around noon (which was besides the most typical).
- Another study found occupants to differ in their arrival and leave times, they namely found them to arrive and depart over a period of 2,5 hour. So the third might arrive early and leave early, and the fourth arrive and leave 2,5 hours later.
- If such occupants are in the same zone, this means that the arrival time of the first occupant determines when the lighting is switched on and the leave time of the last occupant when the lighting is switched off. And because two of the four of them tend to stay at their desk the whole day lighting remains switched on between these times. This results in lighting use that’s far from optimal.
- This brings me to my main research question: how can occupancy-based lighting be optimally used in open-plan offices? By answering this question I hope to prevent these situations to occur any longer.
- So, what have already been studied on this topic. Well , they have been mainly studied in private offices as in this context it is relatively easy to achieve optimal lighting use. Von Neida, Manicria & Tweed for example investigated the energy savings that could be achieved by optimizing the time after which the lighting is switched off when an occupant leaves his office. Their results show clearly that the shorter this time delay, the higher the energy savings. A time delay of 5 minutes means that lighting will be switched off for short leaves, e.g. a visit to the restroom.
- So what if you apply this strategy to an open-plan office? If the lighting would be switched off and on each time one of the occupants in the open-plan space leaves for 5 minutes, you would get an effect like this. That can become annoying, especially because it won’t be just one co-workers’ behaviour but a number of them. So, t lighting control strategies cannot be transferred directly from a private office to open-plan offices as we need to take the comfort of the co-workers’ into account.
- So I want to perform several studies to be able to handle this issue. First I want to increase the knowledge about individual occupancy patterns: why do occupants differ in their patterns? What type of user tends to have the green profile? And which the blue profile? So which individual characteristics play a role?
- Besides, are their patterns influenced by spatial characteristics? Like whether their desk is located close to the restroom? And whether their desks is located in a more private/concealed area or in a more busy area?
- And how are these affected by time characteristics? Bouffaron found the occupancy diversity factor of the building, thus the part of occupants present of the total amount of workers, to vary between months and days and also to depend on the proximity to a holiday.
- And occupancy patterns are not just the result of individual choices, they are limited by restrictions from above, like state holidays and sickness, but also obligations by the company, like these LEDtalks are for our building lighting group.
- After assessing these individual patterns occupants with similar patterns can be clustered. So while first there were four different occupancy profiles in one zone
- now occupants with four similar occupancy profiles are grouped together and lighting will be used more optimally. Hereby it is important to account also for lighting preferences, like preferred illuminance level,
- And workspace preferences. It is likely that occupants prefer a certain type of workspace, e.g. close to the window, or a desk that is more concealed. These should also be taken into account when assigning them to a specific workplace. This might also benefit the acceptance of the clustering as assigning them to a specific workplace might namely make them feel out of control over their work environment and therefore not be accepted. But by meeting their workspace preferences and lighting preferences as well as occupancy profiles both energy savings in lighting and user comfort can be established.
- Then I want to develop lighting control strategies that are tailored to the open-plan office. I want to investigate how the control characteristics should be set to guarantee the comfort of the co-workers. At which time delay occupants are not bothered by their co-workers’ occupancy behaviour? Might dimming be a solution to minimize the discomfort of co-workers?
- Besides I want to investigate I want to investigate whether it is possible to tailor the lighting control strategies to the different individuals within a zone, so whether lighting can be controlled on a desk level.
- Garg and Bansal namely found the activity levels of occupants to vary over the day.
- They consequently tailored the time delay setting of the lighting to the different activity levels. This means that with a high activity level, or short inactivity periods, the time delay is shorter, as the occupants leaves the room often. Again this study was performed in a private office, but it is promising strategy and could be successful in open-plan offices too if the comfort of co-workers is taken into account.
- These studies all contribute to the aim I want to accomplish in my PhD: I want to develop lighting control strategies that are tailored to occupancy patterns so that lighting is used optimally but most of all that create comfort of the worker and the co-workers.
- My name is Christel de Bakker. I have a mixed background: I did my bachelors in the Built Environment and graduated this summer at Human Technology Interaction, here at Eindhoven University of Technology. From the 1st of September I joined the Building Lighting group as a PhD. I will investigate how lighting can be tailored more precise to occupancy patterns in open-plan offices.