Highlights
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2024-06-29 15:49 So this is, this is rooted really in this first research. And then after that, I had several projects with different companies and different institutions about light and daylight. And I started being more specialized in that field. And then I’ve been working as a specialist to help architects to design their buildings with better daylighting conditions for occupants, both at white architects. But also before that, I was working a little bit on the side for a company in Canada called co architecture at that time and on some projects. And then I’ve been continuing as associate professor both at Laval University in Quebec City in Canada, and then in Sweden at Lund University
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2024-06-29 15:49 I mean, passive houses were starting in 96, so that’s the same time I started my PhD in 96, and we built the first passive house in Sweden, 2001. So that was really the beginning of that movement. And at that time, we thought that making a passive house was kind of rock science. It was like something that was so advanced. And today, I mean, normal houses are almost like passive houses in the building code.
- Note: The evolution from passive houses to carbon neutral buildings marks a significant advancement in construction practices. Beginning in 2001 with the construction of the first passive house in Sweden, the concept was once viewed as advanced and almost like rocket science. Over time, the standards have evolved so much that today, normal houses almost meet passive house criteria dictated by building codes. The focus has shifted from passive houses to carbon neutral and energy-positive buildings, reflecting major progress in sustainable building practices. This evolution underscores the importance of integrating technical advancements with lifestyle choices and priorities to effectively address energy challenges.
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2024-06-29 15:52 So we need to stop constantly relying on the artificial solution. I think we ought to make buildings much more simple and robust and functioning in the natural world as they are. Considering the challenges of the climate change. Now, what are the latest research that you have been working on during these past months? I have two main projects that I think are connected to light, and one is with my PhD student, Yason Bournas. It’s his main PhD project and it’s about the densifying city and how it affects daylight access. And in that project we looked basically at the effect of increasing densification to a level where you have no daylight, because that’s also a problem, both from the health perspective, hygienic perspective, but also the energy perspective, because as I said before, daylight is a free resource of energy. And people who are proponents of the dense city, they forget that without light in the city center, we cannot have life. We cannot have people thriving, we cannot have healthy people, we cannot have a hygienic life condition, because we know that also that daylight helps to kill bacterias and viruses. And that’s very relevant now with the pandemic that we’re going through.
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2024-06-29 15:52 I need to summarize that somehow and I can give them the reference if they want to go check. So I realized that for the students it was a very big mess. I mean, very difficult to understand what was in my crazy mind. And so I decided that I need to sit down one year and just write down everything I know about this topic or almost everything I know. Of course, it’s not everything I know, but it’s like the basics that you need to know.
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2024-06-29 15:52 And I’m sure there are things missing as well. But at least what is covered in this course is covered in the book. But I’m very happy about the fact that we did it because somehow for me, after 20 years of career in this area, I felt it was time to summarize myself and put order into the knowledge. Like what do we know about daylight quality? It’s chapter eight.
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2024-06-29 15:53 Well, you will come up with things that are very scientific but nothing necessarily very relevant or applicable. And we see that with the european standard, daylighting in buildings that it’s very nice, but it’s not possible in practice with the kind of density that we have today. We see that daylight factor requirements are about twice as much as what we are able to accomplish in a real city. At least in Sweden. I can speak of own experience.
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2024-06-29 17:13 There’s not enough research about this. There’s been a load of research on windows and where you should put your window, how big it should be, what glass you should have. The room behind the window should be designed and all blah, blah, blah. We know all of this sizing a room with respect to side lighting and all this. But when it comes to top lighting, like atrium, for example, as far as I know, the only person who has done serious research about this is Babaramathusia Trondheim.
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2024-06-29 15:54 And then, of course, the latest pandemic situation also puts emphasis on the hygienic issue. And we know, for example, that in China, I think there is a requirement to have direct sunlight in bedrooms for a certain amount of hours during the day, and that’s out of hygienic perspective. So I think that there’s going to be more emphasis on this, especially after Covid, that we’re going to look at it from a health perspective. I mean, daylight, daylighting is ultimately an air quality parameter as well, because it kills germs and bacterias and viruses. So in rooms where you have good day lighting, you have better air quality too.
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2024-06-29 17:17 The first one was done in the US quite a long time ago, I think it was in 94 or something, by Lisa Eskong. They looked at a lot of children, I think 21,000 children, and found that in schools with good daylight, when they could compare the students results, that they were performing notably better, for example, in mathematics and reading skills, like the speed at which they were reading and so forth, it was like 21% or something. I can’t remember the numbers, but it was of that order of magnitude. So that was the first study that pointed that the importance of having good day lighting, that it affect the children’s performance in school.
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2024-06-29 15:55 Normally in classrooms we have a little bit higher level than in normal office spaces. We will speak about, you know, 3% average daylight factor, which for a median value will translate into maybe 2.3 or something, whereas in an office we will be satisfied, for example, with median daylight factor 1.21.5 and average daylight factor 2% or something.
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2024-06-29 15:55 And so there is a big difference between people who are sitting next to windows and the ones who are sitting away from the window. And this affects the light level. It affects also the uniformity of daylight across the room. And this affects visual performance, because ultimately our visual performance is mostly depending on contrast situation.
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2024-06-29 15:55 So the problem with side lighting of classrooms is that daylight is diminishing in an exponential decay from the facade. So it diminishes very rapidly. If you have a room height, which is three meter, then you have a daylight death zone that is about 6 meters, about twice as big. And so if your room is 8 meters, it means the last 2 meters do not have daylighting at all, and probably the last 4 meters have fairly low daylight levels. There’s been a lot of research into this problem
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2024-06-29 15:56 I’m interested to know in practice, if you have the budget and also the freedom to run just one simulation to evaluate a school building or an office building, which metric would you choose? Out of all of the different metrics. That we have now, if I have just one simulation to run and limited budget, I would definitely look at the daylight factor and I would look at a median value in each room. Because the median, by definition, is a geometric metric. The median tells you half of your room is above a value and half of your room is below, right?
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2024-06-29 15:56 So it gives you a very good spatial indicator, whereas an average value gives you absolutely no information, in fact, because you could have a very bright light patch next to the window and a very dark back of the room, and then you still have a high average. So the answer to that question is very location dependent, because if you ask me the same question in Dubai, I will definitely not answer the same
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2024-06-29 17:29 for example, that in an apartment, bedrooms are nothing inside of the regulations. There should still be a requirement that there should be at least one window. Because you also have the problem today that a lot of teenagers are living their lives in their bedrooms, in front of their computers.