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#5: Buildings and Energy

08/25/2022 |

By Birgit Baustädter

Brian Cody is an engineer with over 30 years of experience in the analysis and design of energy efficient cities, buildings and systems.

Brian Cody talks to students. Source: Privat

Talk Science to Me – the science podcast of TU Graz

Welcome to the science podcast Talk Science to Me. Today we are once again dealing with the topic of sustainable building. Today's guest is TU Graz professor Brian Cody. He is an engineer with over 30 years of experience in the analysis and design of energy efficient cities, buildings and systems. And he heads the Institute of Buildings and Energy at TU Graz.

Talk Science to Me: Dear Professor Cody, thank you very much for answering my questions today on the subject of sustainable building. It would be great if you could start by briefly introducing yourself. Who are you? What have you done so far?

Brian Cody: I am the head of the Institute of Buildings and Energy at TU Graz. And for, I guess, 30 years I have been working on this topic: energy benefits of the built environment.

You say for 30 years - where did the interest come from for you?

Cody: Of course, it didn't happen overnight. I studied engineering, but I was always interested in architecture. And for the first few years I was in America, then in London with Ove Arup. That's a big engineering firm in London, operating worldwide. And I was actually in research and development at the beginning. Then in the planning department, I planned projects all over the world. The task was buildings and building physics. And relatively quickly my interest grew in how to get more into this interface, into architecture. Because this is actually where the energy performance is determined to a large extent. That was at the beginning of the 1990s, when the topic gained in importance. It happened, so to speak. But it happened relatively quickly. In 1989 I graduated. In 1992 I was in Berlin when Potsdamer Platz was built and was already fully involved in the events. So in that respect it happened very quickly. The interest is actually curiosity about how to get a better understanding of these physical processes, the energy uses of the built environment. And then using this knowledge to construct buildings and cities that of course have a minimal impact on the environment. But just as importantly, they have a quality of life, a livability as they say, a quality of stay. Improving or maximising people's health and well-being at the same time. That is the motivation, so to speak.

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I would now like to read you a short quote from you: "Against the prevailing backdrop of global warming, rapidly depleting energy resources, exponential population growth, rising geopolitical instabilities resulting from the uncertainty of the future energy supply situation, together with the fact that buildings are responsible for at least 40 per cent of the world's energy consumption, good architecture is not possible without a good energy concept." Is the future really that bleak?

Cody: So what is listed there are simply facts. These are the bare facts. And these days we are experiencing that. Right down to the geopolitical instabilities. And the dependence on systems and places. So in terms of energy supply. All the way to growth. So between this moment and the same moment yesterday, about the population of Graz has been added to the world. So somewhere a Graz now has to be built in 24 hours to accommodate these added people. So every second more than 2.5 people. So these are all facts. Also that architecture plays a big role in this - as I said: 40 percent. So it is dominant, so to speak, far ahead of the other important sectors such as transport or industry. So it's also just a fact. The fact that the picture is so bleak is just the beginning of perception. Or the opinion. The picture is only gloomy if one is of the opinion that nothing can be done about it. Or one doesn't want to do anything about it. Then of course it looks gloomy. But only then does perception begin. That wasn't in my quote either. I don't see it as a gloomy picture, but we can do it if we want to. It's not easy either, of course. That's clear. On the other hand, architecture as a 40 per cent consumer of the total energy demand, as the biggest contributor to the problem, so to speak, also means that the greatest potential is to be found in architecture. So that is, of course, a reason for optimism if you are active in this field. This means that we can find solutions here. When people talk about the professions of the future today, they also talk about biotech or computer science, these professions that are newer. And of course they are very important. But architecture is just as much a future profession. And that is not really perceived in general society at the moment. But if you think about it, it's no less than the biggest challenge we face as a society. So the biggest physical problem, which is climate change and global warming and who is causing the emissions. If architects together with engineers for building technology, building physics and the corresponding fields can find the solution, then this is probably a very important task for the future.

What can architecture do?

Cody: As I said, at least 40 percent of the problem is buildings. Clearly, what we need to do overall is, as soon as possible, globally, in the way energy is used, not just in the built environment - but as I said, that's where most of the energy is used - increase the efficiency and change the delivery of those amounts of energy all the way to the source. If we can do that, then we solve the biggest problem we face as a society today. And will continue to face in the future.

How exactly should I imagine your work?

Cody: My work consists of three essential elements: The teaching, the research and the practice. So theoretical research projects, but also buildings that are actually built. Those are the three elements. But in principle it all comes back to a common denominator: it's about maximising the energy performance of buildings and cities. In terms of teaching, this is also research-led teaching. That means that everything we do there, every semester, every year, is very much intertwined with research projects or things that are currently current in research work or practice. In this respect, there is actually no distinction between these three elements. The work consists of working on these concepts and developing things with the students, with the staff at the institute and the other institutes, with architectural offices all over the world. So this community - every day it's about finding solutions here. That's the work, the fascination, the will to improve. Of course, one could mention maximising energy performance or reducing CO2 emissions as goals. But if you look deeper for the reason or the motivation, then, as I said, it is to develop buildings and develop cities where people's health, people's well-being is improved. First and foremost, that is the motivation. It is actually a positive motivation. To make things even more beautiful, even better. But at the same time, to minimise the negative impact on the environment with all the consequences. Both are important. I think that's important for me, the positive. I think that for most people, positive things are more motivating than avoiding negative things. That can motivate for a short time.

So you have a bit of an idea of what we're researching: In summary, maximising the energy performance of buildings, of cities. There is the building level and the city level. At the building level, we have topics like building in different climate zones. That is a very important element in our work - research, teaching and practice. So developing solutions all over the world, not just limited to certain climate zones. Also in hot, humid or dry climates. In extreme cold. And what that means when you build somewhere else. The relationship between climate and energy or climate and architecture. And that's also the case in teaching, that we work with students all over the world. On the one hand, because this way, if you approach it more comprehensively, the knowledge is enriched in a different depth, and on the other hand, because it is also very important for the future of the students. Architects of the future and even of the present who live in Austria actually have to work all over the world. Only very few of them can, if they want to, limit themselves geographically to an area where they would like to work.

Then: skyscrapers. Skyscrapers are a focus. Natural ventilation of buildings, especially buildings where it is difficult. For example, skyscrapers.

Smart Skins or Smart Façades are a research project. Adaptable, adaptive building skins that react not only to external environmental influences, but also to internal conditions that change. All the way to thinking façades with built-in intelligence, so that the façade reacts and optimises itself. For example, if you have a climate like the one in Graz: Today, for example, today there is an outside temperature that feels like 35 degrees and in six months it will perhaps be -10 degrees. And these fluctuations, also in the relative humidity, wind speed, brightness, etc., are very important. We live in a world that is absolutely dynamic. No matter where you are in the world, you are within this dynamic, trying to achieve comfort for people. But the interior of buildings is also very dynamic. People come, people go. Depending on how the building is used, there are many people, or few people, or none at all. And between these two dynamic worlds - inside and outside - the façade is usually built as a rigid system. That does not change. That is simply static. And that, of course, cannot lead to an optimal result. And that is why we are developing these adaptive, adaptable façades. That is, they can adapt. And on the other hand, they have to know when to do what. That's where the regulation comes in. And in general the development that we find out in research in which spectrum which values have to be changed. So the integration of renewable energy sources in new buildings is an absolutely topical issue now that every building in the EU has to be an almost zero-energy building. And, of course, we also have to establish truly zero-energy buildings or plus-energy buildings as the standard as soon as possible. The integration of photovoltaics and other renewable energy technologies into building design is a very, very important area in which we are researching.

And of course it is also very, very important how you can ultimately evaluate all of this. How to evaluate whether it is good or bad or average. How to compare them with each other. This is an area that is also very interesting for me personally and where we have also done a lot of research. It's about the concept of efficiency, energy efficiency, and how it can be evaluated. Efficiency is a term where everyone knows what it means. But nevertheless, it is often misused or misunderstood. Especially in the building sector. When we say: "This is an energy-efficient building". The first thought is often that it uses little energy. But efficiency is always to be understood as a relationship, as a ratio between two variables. In short, it is about benefit and effort, or input and output. And in buildings it is no different. You have to consider what the benefit is and what the cost is. And in buildings, according to my definition, it is the relationship between the achieved quality of the indoor climate, the indoor climate, the quality of stay in the building and the necessary amount of energy that has to be supplied to maintain this quality. In other words, a concept of efficiency that can be measured quite objectively. Years ago, I developed a system called BEEP - Building Energy and Environmental Performance - with which you can actually form this relationship for the first time. And so you can also compare different buildings with each other, or compare the different design options for a particular building with each other. And in a similar way, when it comes to the efficiency of cities, even though it is of course a broader topic, it can in principle be understood as the relationship between the quality of the city - livability - and the effort, the resources that are necessary to create this quality. And it is not only the evaluation methodology, but this understanding that is very, very important. That efficiency is not understood too one-dimensionally, that one simply uses few resources and does not consider what comes out at the other end.

If we are now with the city: We have research projects where it's about urban form and energy. Basically different forms of the city - how the city should be built with which typology, in which configuration the city should be built in a certain climate to maximise the energy performance of the city. Outdoor comfort is increasingly a very topical issue, where we are also working more. There is also a lot of talk about the heat in the media these days. These are topics that come up and are gone again in a few weeks, of course. But you can feel that it is gradually getting warmer and that this is creating problems. And this urban heat island effect. But as I said, we are building projects all over the world and this is felt even more in the Middle East, the Far East or in many areas that have a much more extreme climate than Austria. Here it is increasingly about how to create what we call outdoor comfort, not only in the buildings but in the spaces between the buildings, so that the city is livable. That the city has a quality where you don't immediately run from the car into the building, but that the city really functions as a city. That has a lot to do with comfort. Thermal comfort, wind comfort and so on. The challenge is how to do that without producing energy or CO2 emissions.

Then we work on future city visions. So basically in theoretical research: If we build a city and optimise it in a holistic sense of the overall city system - what would this city look like? We have projects that go as far as the integration of vertical farming - food production in the middle of the city. Here we have projects like the Hyperbuilding City. You could say that these are models of thought, but they are intended to provide impulses on how to continue building cities. And actually we are working on cities that are being built at the moment. That is something that is happening. Cities are being built from scratch. But these questions and this research are not only important for these cities, but for all cities. Because there is a misunderstanding here when people think, and I often hear this when I talk about these topics in Europe, that this is only interesting for China and India, because everything has already been built in Europe and we only have to redevelop everything. And that is a misunderstanding. So the question of stock is so often emphasised. And that is of course an important element. If you look today, depending on how you measure it, 99% is stock of what is there today. 1% is still under construction. But, and this is the important distinction in how you look at it, if you look at what happens between now and in 50 years, and if we continue to be as conservative as we have been up to now, then after these 50 years in a city like Graz or Vienna, more than half of the buildings that will be standing then will be so-called new buildings that will have been built. In this respect, it is absolutely wrong to say that we only have to renovate and see what we do with the existing buildings. In the medium term, new construction is just as important. But it is even more important to look at the whole thing as a holistic system and to consider what of the existing buildings should be retained and what will fit into the image of the city in the future. Because all that can be retained is, of course, a reduction in CO2 emissions that would go hand in hand with a new building. But on the other hand, if you simply say: we have to keep everything that's there and we'll see how we get on, then that leads to the wrong results. Because there are already situations within this overall picture where you have to say that demolition here opens up a different potential, where over the next 50 years much less CO2 emissions will take place than if we keep it.

Interestingly, we also did a project where it goes beyond this city level. Beyond the scale of the city. Where it's about the social forms in principle - how a country is configured in general, the energetic structures in principle of an entire country. That was perhaps this project ten years ago. We concentrated on the question of how teleworking could be used, for example. So this virtual infrastructure that we built ten or 20 years ago allows us to work anywhere, that you could actually have a completely different physical infrastructure. But we still continue to build the city as we did 100 years ago - the streets, the buildings, living, working, traffic routes and so on. The question was basically: if we were to consistently use the virtual infrastructure that we have and with this knowledge of the existence of this, configure the physical infrastructure differently consistently with the aim of maximising energy performance and reducing CO2 emissions, how would we build the city? It was basically, in short, rethinking the city. Here we basically modelled service companies consisting of residential buildings, office buildings, servers, data centres, transport routes and so on and so forth. And then we ran through and examined various what-if scenarios. In principle, the result was very interesting at the time. We showed that if we rethink the urban system and consistently use teleworking, so that people work three days at home, two days in the office, for example, that you can do more than anything else we do as far as photovoltaics and thermal insulation and all the other strategies that are practically implemented, that the potential was greatest here. Here we could actually get from the 5,000 watts per person energy consumption that we have as Europeans to about half. That is where we need to get to. If we would really implement such a model. At that time there was general interest. But everybody said that nobody wants that and we can't do that. In 2020, from one day to the next, we suddenly saw that it was possible. In the short term, this effect also occurred, but the difference is that you have to implement it consistently. Just working a bit at home, just working a bit in the office and driving back and forth a few times every day is of course not the solution. You have to implement the whole thing consistently. But as I said, it was interesting for me, this pandemic and how quickly it was suddenly possible. Many people said at the time: You were right about the project! Energy consumption did indeed drop for a short time. Many are of the opinion that things will be very, very different after the pandemic. I'm not so sure. But maybe we have seen something else. Namely, if we really want to or have to, then many things are possible that one otherwise thinks are not possible. We spoke at the beginning about this gloomy picture. It is not gloomy because many things can be done. The question is why we don't do it on a large scale, when we actually almost all - I wouldn't say every single one, but most - know very well that time is running out, that everything has to be done as soon as possible. And nevertheless it is being postponed. And because this danger, which we probably recognise, is not so close. And the human being reacts intuitively only when the danger is really close. Corona, for example, is such a situation. And climate change, which is a much more important challenge, is much more dangerous, but it's not happening today. Not tomorrow either. So that is the explanation I think. Of course, more could be done.

With the concept you have just mentioned with three days teleworking and two days in the office - was that the only change that was made or has the whole city concept been changed as we know it now?

Cody: At that time, we didn't simulate a specific city, but the structures of a city and we consistently redesigned the city. And if you were to implement that further, the city would have to change physically as well. Because if we were to implement this consistently, then we would realise - which many have realised in the last two years, for example - that you need more than a kitchen table to be able to really work at home. At the same time, which cannot happen so quickly, if less work is done in the office and if it is used more effectively, you would have to configure office buildings differently, plan them differently, build them differently. More as a communication centre. The traffic routes, because there is less traffic, change in a consistent way, because if you were to continue building the city in the future, knowing that the virtual infrastructure exists, you would have to build the physical infrastructure differently. It has a lot to do with efficiency. We have developed a unit to measure all this - cubic metres/hours. So the product of space and time. If you do that, then you can assess how efficiently the infrastructure is being used. And so you see, we know this of course, our roads are 100% utilised for an hour in the morning, for an hour in the late afternoon. But for many hours over the 24 hours almost not at all. Residential buildings can also be looked at in this way. Office buildings even more so. Courthouses. Schools. And so on. If you just think about how much of this infrastructure is often unused, empty - it's pure luxury or inefficiency. This project went in that direction. And then, of course, we pointed out, if you go further, what would also be possible. It was actually about, in the end, and this is also a topic that is becoming more and more topical, the extent to which you have to own things or the extent to which you can use things. Up to buildings, cars, everything in principle. This is a development that we are now slowly but surely actually experiencing. Because that's how you get to other possibilities, how things are simply used more efficiently. But also, in principle, in terms of people's happiness and carelessness and many philosophical questions that can perhaps also be answered here. So the project was very theoretical and future-oriented. But over the past eight years, interestingly enough, we have seen a lot that gives us hope, that the research in this project has shown and that in principle the trigger for this project was that simply optimising the existing or repairing the existing system, patching it up here and developing it further there, does not bring about the necessary reduction. As I said, we have 5,000 watts per person in Europe. And we have to get down to about 2,000. At least. That means halving it. And with models that we have built before, where we have run through what-if scenarios - what if all cars are electric, what if all buildings are passive houses, what if the thermal insulation is half a metre thick - all things lead to changes that are simply not enough. And they are partly nonsensical, of course - but that's another question. But they don't produce the necessary effect. And that means we have to rethink the city. We have to think radically, how do we get there on a large scale? Then consider what that means for the different elements of a city. But that was basically the trigger.

If one looks a bit into your work, one also reads very often about the use of natural forces. What exactly is meant by that? And how can this be integrated into the cityscape or even into individual buildings?

Cody: What we call energy design is, in simple terms, the use of natural forces. These are forces such as solar energy, wind, daylight. In other words, the environmental conditions with which we are surrounded. Since the beginning of modern architecture at least, we've been trying to protect ourselves from that. If you look at the terminology in building, there are terms like windbreak, sunbreak, vapour barrier, vapour retarder and all these terms. The whole thinking is how can we protect ourselves in a building from these elements. And that leads to the fact that we then have to make do with energy supply, which at the moment is 80 to 90 percent based on fossil fuels. The solution is to make use of these natural forces and work with them to achieve the result you want. Namely, a comfortable indoor climate. Interestingly, often what seems to be a problem at the site for a particular project - for example, the sun in a hot place, or the wind for a high-rise building, or the daylight that is harmful to the exhibits in an exhibition - is that often it is precisely the use of these hostile forces that leads to the solution. That is, we have built buildings where we use the sun to cool the building. We have built buildings where we use wind in a high-rise building to ventilate it naturally. Or we use daylight in a controlled way in a museum, where the light is brought in in such a way that it is not harmful and that it is used for lighting, instead of, for example, black box, nature stays outside and then the climate and the light have to be provided artificially. So in principle it's a bit like the martial arts in Asia, where you stop and redirect the attacking forces and then use them against the opponent, so to speak, to achieve what you want to achieve. Maybe that's how you can describe it. But there are not many of these forces either. It's about the outside temperatures, for example, exploiting the rhythm between day and night with thermal storage mass, night-time cooling. The sun is of course the most powerful force. Wind is important. But working with these to achieve the desired result as far as possible in a passive way in terms of light, indoor climate, air quality and so on, and then of course using wind power or solar power to generate energy with renewable energy sources that provide the necessary energy.

If money were to play no role in your research - what would you then want to implement? What would be the most urgent thing in your eyes?

Cody: Where you could do something sensible with more money or with a lot of money, and which would of course be very welcome, would be to build demonstration objects on the one hand. That is, of course, a luxury that you don't have. That would be interesting, of course, because in principle these innovative things are rarely actually built. Sometimes we do such mock-ups on a small scale. But demonstration buildings would be interesting. And a very, very important topic that is related to that is monitoring. That is, measuring in buildings that we are constructing, but also in those that have already been built. The construction industry is basically the only one where we continue, almost without any feedback from what we have done. There is very little measured value and feedback and experience from what is there. It's basically a vacuum. That is, each building is then rebuilt with only conditional knowledge of everything that has happened so far. And money is not the only problem. Of course, sensitive data is also at stake. But money certainly plays a big role. If we had a lot of money, I say it should be invested to get more feedback on what we have done.

Thank you very much for answering my questions today!

Cody: You're welcome! Thank you for the invitation!

Thank you very much for listening to us again today. See you next time!