Of the roughly 8,700 hours that make up a year, Americans spend upwards of 90 percent of that time indoors, from three-walled cubicles in office buildings to classrooms to time spent traveling in cars. Despite this staggering number, we rarely consider the quality of our indoor environments, especially in workplaces. In addition to this, about 40% of total US primary energy use is coming from buildings. There is an urgent need to make buildings more energy efficient and pleasant at the same time. These challenges set new objectives for designers.
PhD candidate in Building Science in Architecture Caroline Karmann has dedicated her time as a student and as a working professional to better understand and ultimately improve just that: how to improve indoor environmental quality in buildings while saving energy. Originally from France, Caroline spent time working in the engineering sector in Germany after receiving a dual Masters degrees in Architecture, and in Climate and Energy from the National Institute for Applied Sciences, Strasbourg, France. As a graduate student researcher for the Center for the Built Environment, her work focuses on indoor environmental quality, specifically in conjunction with the use of radiant systems.
Below is a interview with Caroline on her latest research and future endeavors.
What led you to building science program?
I graduated with a degree in architecture in 2006. I had done a few internships at that point, but I wasn’t ready to go to work right away. I felt that I still wanted to learn more, and became interested in the energy aspects of design. The university had an engineering program, so I asked to bridge toward the energy department and they accepted. After that, I worked for Transsolar in Stuttgart, Germany for 4 years. I was very interested in working for them because they were very innovative in their practice, extremely proficient with energy assessments and they were also able to work closely with architects. It was a way for me to work and learn about energy while still feeling strongly connected to designers. While working I also came back to my school in Strasbourg to co-teach an interdisciplinary studio on low-consumption buildings. I enjoyed this experience and I got excited about exploring further academic options. I wanted to get back to school to get my PhD and got very attracted by building science program offered at Berkeley.
You specialize in indoor environment quality. Where did that interest stem from?
By definition, Indoor Environment Quality (IEQ) refers to four main aspects of our environments: thermal comfort, air quality, sound quality, lighting comfort. When I was working for the engineering firm I felt that the knowledge on energy was there. Yet, that we did not know so much about indoor environment quality in buildings. I felt like we were trying to fit buildings within certain limits of daylight or temperature and I wanted to know what exactly was behind all that. I was interested in these limits, especially because of the implications they have on energy. Berkeley has such a good program for building science, and when I came here I understood that this was such a very relevant topic: We spend about 90 percent of our time in buildings, so it becomes a question of how to make indoor environments pleasant to be in also from non-visual and more perceived environmental aspects like noise or comfort, while properly understanding the implications in terms of energy use.
You note using radiant systems in your research and study. What are they?
A radiant system is a conditioning system that exchanges heat (thermal energy), mainly by radiation. It is a system with a lot of advantages from an energy perspective because it’s usually implemented on large surfaces (a whole ceiling or floor, for instance). Because they use a large surface area, radiant systems allow you to have a smaller temperature difference between the conditioning fluids and the environment (compared to other systems). All of this makes it a perfect system to be combined with renewables. It also takes less energy to transport water in buildings due to its higher heat capacity (compared to air). Overall, radiant systems are very interesting from an energy perspective. The question I was raising in my research basically asks how radiant systems relate to IEQ. My research is centered around three big questions: : How do radiant systems impact IEQ in buildings? Do they allow improved thermal comfort as compared to more conventional all-air systems? How can we make them work together with indoor acoustics?
What does that research entail?
Because radiant systems exchange heat using thermal radiation, there is an assumption that you shall not cover them. In case of massive radiant types, this assumption leads to exposed concrete that create high reverberation in spaces. For my study on acoustics, I was conducting lab experiments to address acoustical coverage of a radiant chilled ceiling. I worked for two weeks in a lab where we tested a simulated office space with a radiant cooled ceiling and free-hanging acoustical clouds with. We also used fans to play with convection. We ran a number of tests and changed parameters such as acoustical coverage and forced air movement.
For my study on indoor environmental quality and radiant systems, we are currently conducting surveys in 50 radiant buildings. I am going to compare these occupant responses to a benchmark coming from conventional all-air buildings to learn how radiant systems impacts thermal comfort and more generally IEQ.
What are you hoping to communicate through your PhD in the larger architectural community?
I’m hoping to address some of the limitations found in the implementation of radiant systems to make sure that if we do use this technology, we do it properly. It’s a technology that has so many advantages from the energy side, and we don’t want it to fail simply because we don’t fully understand some of the basic human-technology interactions related to it. I want to make sure the systems are more comfortable, encompass all aspects of the built environment such as acoustics – a big problem in many office settings – and I want to know how people perceive thermal comfort. There is an assumption that radiant systems are better for thermal comfort, but we don’t really know if that’s necessarily better or the best solution for comfort. I’m hoping to address some of the limitations of radiant systems. There are many successful examples of them, but very often we forget to include the perception of the buildings’ occupants. You can have a building that’s built well, looks great and is all over the architecture magazines, but what we don’t know is if that space functions for the people working inside in the way designers have imagined. Maybe they would say it’s way too noisy, or uncomfortable.
What are your plans after graduating from CED?
It’s difficult for me to say right now. The path I’ve come down thus far was based on a lot of coincidences in a way. If you had asked me this question one year before I graduated from the architecture program in Strasbourg, I wouldn’t have expected to ever go so far into engineering, or even go for my PhD in building science. Research can be really exciting. I enjoyed learning about the scientific methods and its rigorous approach to problem-solving. While I love what I do, I also feel that I miss the real world. I’m currently part of a student competition which involves designing and building a Tiny House. It’s so pleasant to see the progress we are making and to know that whatever we are planning will actually happen. It’s also an amazing learning exercise and a unique chance to test our ideas. I found it a very compelling learning tool. For now, I think I would like to stay within the world of universities. It’s a very rich environment and I have enjoyed both my research and teaching experiences so far. But academia may not be my unique option at this point. Overall, I would like to explore ways to better bridge building design and the knowledge we accumulate through research in the field of energy and IEQ. We often see those aspects being addressed through requirements and checklists but we also need creativity. The successful implementation and adoption of sustainable strategies in buildings is often a bigger challenge one may think it is. Designers have an important role to play.