Rumoer 59: Comfort| BouT | TU Delft

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periodical for the Building Technologist



student association for building technology

59. Comfort

’ es


am ‘W t en comforta n a g e be el l


Het uitgangspunt bij het ontwerpen van deze stoel was het maken van een luie ligstoel die zo transparant mogelijk oogt en die, als de stoel niet wordt gebruikt, nauwelijks volume heeft. De details zijn eenvoudig gehouden. Als basismateriaal voor de stoel is gekozen voor verenstaal vanwege het flexibele gedrag bij belasting. De zitting is van canvasdoek bekleed met leer of textiel en de losse rugelementen worden via kabels aan het frame bevestigd, waardoor de stoel zeer flexibel en dus comfortabel is.

Jan Brouwer +31 6 51 31 62 50 Chris Karthaus +31 6 46 32 70 21

Cabinet 02.West.090 Faculty of Architecture Julianalaan 134 2628BL Delft The Netherlands PRAKTIJKVERENIGING


student association for building technology

+31 (0)15 278 1292


RUMOER 59 February 2015 20th year of publication Praktijkvereniging BouT Room 02.West.090 Faculty of Architecture, TU Delft Julianalaan 134 2628 BL Delft The Netherlands

RUMOER is a periodical from Praktijkvereniging BouT, student and practice association for Building Technology (AE+T), Faculty of Architecture, TU Delft (Delft University of Technology). This magazine is spread among members and relations. Circulation The RUMOER appears 3 times a year, 150 printed copies circulation.  Digital versions are available online at:

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Credits Edited by: Koen Fischer Marc Nicolaï Text editing: Koen Fischer Marc Nicolaï Reinier Scholten Jelmer Niesten Cover design:

Koen Fischer

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Gebouw X by Broekbakema (courtesy of Broekbakema)

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From the board


Travil report: BouT goes to Berlin 6 by Anne Struiksma A healthy and comfortable indoor environment: now and in the future 10 by Prof. dr. ir. Philomena M. Bluyssen Overcoming Fears of Adaptive Comfort in Design 16 by Chris Mackey Light in design 24 interview with Erik van Eck Light in research 32 by Anne Leeuw and Alois Knol Creating acoustic comfort in noisy environments 38 by ir. Marten Valk and ir. Bastiaan Beerens The design of a multifunctional exhibition hall 42 by ir. Lotte Baerends Heat recovery with hybrid ventilation in office buildings 48 by ir. Reinier Scholten Sustainable indoor climate with BaOpt 54 by Ronald Houtsma


Usually when we write or read about buildings it is about their physical appearance. But in contrast to how we write, we often speak about light or dark buildings, cool or hot buildings, quiet or noisy buildings. When making use of a building, rather than talking about its physical appearance we tend to speak about the comforts of a building. This issue of Rumoer is completely dedicated to comfort, which we divided in four different aspects: Heat, Light, Acoustics and Air. Philomena Bluyssen, professor at the Delft University of Technology has provided an introductory article. Her field of expertise is indoor climate and her article will introduce the four aspects of comfort in buildings. For the aspect of heat we found Chris Mackey from MIT available to write about his work in adaptive comfort design. He tells us about a framework for dealing with changing conditions and his vision for the future of climate conditioning. For the aspect of light we had an interview with Erik van Eck and Sander Veenstra from Broekbakema architects. Part of their portfolio consists of large buildings in which they pay a lot of attention to natural daylight. We also approached two students, Anne Leeuw and Alois Knol to share with us their study on light comfort in an elementary school. Then we have two articles about the aspect of acoustics. The first article is written by Marten Valk and Sebastiaan Beerens, both researches at Deerns, where they develop the “Silent Cube”. The second article about acoustics is written by Lotte Baerends, she recently graduated at the Delft University of Technology with the design of a flexible and multifunctional exhibition hall with integrated acoustics. Finally the aspect of air is covered by Ronald Houtsma, who tells us about a new air handling system called “Baopt”, and by Reinier Scholten who recently graduated from the Delft University of Technology with his design for an adaptable hybrid ventilation system.


From the Board 2014

This issue of Rumoer comes out as we are halfway through our 20th anniversary year. IN this issue We will reveal our six new board members who are very eager to carry BouT through 2015. But before we introduce the new board, lets go back a few months. The past couple of months BouT organized some very well received activities both to celebrate our anniversary year and also just because we are BouT and like to organize activities for our members. Last November, for the first time in many years, 16 enthusiastic students and one accompanying teacher went on a BouT trip. In their report on the next page they will tell you all about the highlights of their experience of their trip to Berlin. Next to the amazing trip there were several drinks and even a BouT movie night. We also threw the biggest BouT barbecue ever. More than 100 people joined and enjoyed the burgers flipped by Marcel Bilow. Last but not least we are very excited to introduce to you the new BouT board for the year 2015. Carlijn, Frederico, Ali, Roxanne, Ahmed and Marc: Good luck and all the best wishes! BouT 2014 Pasquale, DaniĂŤl, Maya, Maaike & Koen


From the Board 2015

Since February 18, BouT has a new board for the year 2015. First we would like to thank the previous board for the great example they set with their enthusiasm and the effort they put into BouT last year. We’re looking forward to a great year organising BouT events for all of our members and continuing to fuel the great BouT spirit of curiosity and collaboration. We hope to see you all at one of our events soon! BouT 2015 In the picture above, left to right: Ahmed Assad (Education), Roxanne Kiel (Media), Frederico Riches (Finance & Sponsoring), Carlijn van der Werf (President), Marc Nicolaï (Rumoer) and Ali Sarmad (Secretary).


Travel report: BouT goes to Berlin

by Anne Struiksma Very early in the morning of Wednesday November 12, our group of 16 enthusiastic students and one accompanying teacher started their journey to Berlin, Germany. Halfway on our train ride to Berlin we stopped in Wolfsburg for our first scheduled excursion. Two students had prepared a presentation for the whole group. Afterwards we had a guided tour through this unique location with exposition, garden and pavilions. Each pavilion represented a car brand, a perfect example of how architecture creates the right atmosphere for different purposes and representations. Passing by Zaha Hadid’s Phaeno Science Centre, we continued our train ride to Berlin, where we arrived in the evening to conclude our first day with a nice Moroccan dinner. Thursday we began with a more cultural and orientational excursion: Berlin by bike. Our guide lead us along Berlin’s architectural and cultural history. Mainly due to the rise of the Wall, different parts of Berlin have seen poorer times in that were of great influence in its (urban) redevelopment. Many impressive sites, sights and stories later, we enjoyed a typical curry wurst dish and went on to visit the headquarters of John Mayer Architects. After an elaborate presentation we visited their JOH3 building, where again two students had prepared a presentation about the building.



Friday was a day of many walks and visits. We began the day with a piece of Dutch pride: the Dutch Embassy by Rem Koolhaas. We continued via the DZ Bank by Frank Gehry, to the Sony Centre by Helmut Jahn and ending at the Neue Staatsgalerie by Mies van der Rohe. All buildings represent innovative and outof-the-box design and technologies. Continuing this trend, we visited the Zendome company in the afternoon. Here we were welcomed and lectured by its founder and creative director. The rest of the day was free-time, different groups went on different cultural trips to the Hamburger Bahnhof Museum, the Jewish Museum, Tranenpalast (Palace of tears) and more. Afterwards we gathered at the hostel to spend the evening to gather to celebrate a birthday. The entire Saturday morning was spent touring Tempelhof, the enormous second World War airport of Berlin. Our guide, an Architectural Historian, completed our tour with showing us the technological grandeur, the building physics and service systems, the bunkers, all the while explaining the historical events that influenced the Tempelhof’s design and development. After lunch we visited the Architectural Drawing Museum, an interesting building in itself, let alone its exhibition, and AEDES which coincidentally presented an exhibition on our well-known Mecanoo. Sunday was our last day, so we had the optional item on the programme to visit to Reichstag, where we could behold the innovative kinetic climate roof. After this different groups scattered to visit some last cultural sites before gathering at the hostel to jointly visit and travel to Berlin Haubtbahnhof, where we heard our last student prepared presentation and took the train back home.



A healthy and comfortable indoor environment: now and in the future

by Prof. dr. ir. Philomena M. Bluyssen 1. Introduction How to achieve a healthy indoor environment has been an issue among architects, engineers and scientists for centuries. However, it was not until the early decades of the twentieth century that the first relations between parameters describing heat, lighting and sound in buildings and human needs were established. A big challenge of today lies in the accomplishment of a sustainable and low-energy built environment and at the same time a healthy and comfortable built environment. Optimization of Indoor Environment Quality and Energy Efficiency is hampered by a lack of information regarding which indicators, criteria and interrelations need to be considered. Previous studies have shown that relationships between indoor environment conditions and wellbeing of occupants are complex. There are many indoor stressors (e.g. thermal factors, lighting aspects and radiation, noise and vibration, smell (odour) and chemical compounds, particulates, moisture and mould) that can cause their effects additively or through complex interactions (synergistic or antagonistic). It has been shown that exposure to these stressors can cause both short-term and long-term effects. For most of the time, science has relied on the optimisation of single factors such as thermal comfort or air quality.

The realisation that the indoor environment is more than the sum of its parts, and that its assessment has to start from human beings rather than benchmarks, has only been gaining ground in recent years. The understanding of that indoor environment has only just began. 2. Facts and gaps While most people are aware of the importance of the outdoor environment, especially in relation to climate change issues but also related more directly to our health, the effects of indoor environment quality are not that common knowledge. Who doesn’t know by now that air pollution such as fine dust and

Figure 1. What is indoor environment quality?


Prof. dr. ir. Philomena M. Bluyssen was appointed full Professor Indoor Environment in 2012 at the Faculty of Architecture and the Built Environment, Department of Architecture, Engineering and Technology, in de Section Climate Design, which she is currently leading, after working for more than 21 years for TNO. She coordinated several European funded projects on the optimisation of energy consumption and indoor environment quality. She is member of the international societies ASHRAE, ISIAQ and CIB. She has written more than 175 publications on national and international conferences and journals. For the Indoor Environment Handbook: How to make buildings healthy and comfortable, she was awarded the “The Choice Outstanding Academic Titles of 2010 Award.” Her book titled ‘The Healthy Indoor Environment – How to assess occupants’ wellbeing in buildings’, was published by Taylor & Francis in November 2013. email: noise pollution from aeroplanes are important issues, or that too much sunlight can be very unhealthy. Most of us don’t realize that people in the Western world in general spend 80-90% of their time indoors (e.g. at home, at school and at the office). Exposure indoors is thus much longer than outdoors. The indoor environment can be described by the environmental factors or (external) stressors; indoor air quality, thermal quality, acoustical quality and visual or lighting quality (Figure 1). These various factors have slowly become incorporated within the building process through environmental design. In the last decade or so we are confronted with new diseases and disorders related to indoor environmental quality such as mental illnesses, obesity and illnesses that take longer to manifest, among which cardiovascular and chronic respiratory diseases and cancer. If you look at the scientific outcomes it seems that staying indoors is not good for our health, even though the conditions seem comfortable enough (according to the standards we apply, according to the control strategies we have taken). Why do we have still do not have this under control? Even after more than 100 years of R&D. It seems at least two major gaps contribute to an explanation for this situation.

Gap1 Starting with the first one: a gap or lack of knowledge shown by the discrepancy between standards and end-users wishes and needs! Even though standards are met, complaints and symptoms occur. The health and comfort indicators we are today familiar with can be divided in three groups of indicators: • The occupant or end-user: such as sick leave, productivity, number of symptoms or complaints, health adjusted life indicators or specific building related illnesses. • The dose or environmental parameter: concentrations of certain pollutants, temperature and lighting intensity. • The building and its components: certain characteristics of a building and its components, such as possibility for mould growth and even labelling of buildings or its components. Of these groups of indicators, the dose related indicators are used most frequently in guidelines and standards. But the doseresponse mechanisms are not straightforward. Ventilation rate is a good example of this. Based on either CO2 as an indicator for bioeffluents or on certain emissions of building materials, minimum ventilation rates have been discussed and are still being discussed for almost two hundred years now (Figure 2). Also with thermal comfort discussions are prominent present. Another model, based on field studies of people in daily life, slowly begins to win ground: the adaptive comfort model, in which the 11

indoor environment, involves many stakeholders, such as the investor, owner, the end-user, the contractor, sub-contractors, local authorities and pressure groups. If those stakeholders do not understand each other, problems can occur. But answers can also be found in the fragmented structure of the buildings sector, leading to lack of coherency and slow take-up of innovation. In other words, the general awareness of what indoor environmental quality is, how you can improve it and who should or can undertake actions, is poor. Figure 2. The recommended minimum ventilation rate over the years.

context and preferences of the occupant are considered to be important. And then even more recently it was suggested that thermal neutral conditions do not have to be necessarily healthy. While current guidelines are focused on providing sufficient task lighting, research on biological lighting demands has revealed that the dosing of natural light is important for health purposes. The amount of light that enters the eye affects our bio-rhythm: under influence of light, the hypothalamus signals to the pineal body to produce melatonin, a hormone that makes us want to sleep. If exposed to light during night, the production of the antioxidant melatonin is immediately stopped, alertness and core body temperature is increased and sleep is distorted. And last but not least, noise has been associated with direct and indirect stress reactions. Annoyance is an important aspect in this mechanism. It seems that noise effects do not only occur at high sound levels, but also at relatively low environmental sound levels, when certain activities such as concentration, relaxation or sleep are disturbed.

Gap 2 A second gap is related to the use of knowledge. The discrepancy seen between what end-users want/need and what they get, points not only to a lack of knowledge but also to an inefficient or wrong use of existing knowledge. Answers should be found in the way communication takes place in the building process, lead by the different stakes of the stakeholders involved. The dynamic process of designing, constructing and managing the


3. Needs To cope with these gaps we need first of all a different view on IEQ. The current view only considers single-dose relationships. With the exception of health-threatening stimuli, the complexity and number of indoor environmental parameters as well as lack of knowledge make a performance assessment using only threshold levels for single parameters difficult and even meaningless. We need a view in which for different scenarios, possible problems, interactions, people and effects are all taken into account. Focusing on situations rather than single components. How we evaluate and respond to our environment does not only depend on the external stressors involved (physical and psycho-social), but also on personal factors and processes that occur over time, influenced by past events and episodes. They all determine the way external stressors are handled at the moment or over time (Figure 3). And they are all important to consider when an attempt is made to pinpoint the effects caused by different stressors (or combination of stressors). This means that besides a different view on IEQ it is important to consider other assessment methods and indicators. 4. Challenge: healthy, comfortable and sustainable retrofit Except for the health effects that are already tangible now, possible consequences of climate change for the indoor environment quality should also be considered. This means that we are not only searching for ways to reduce the use of fossil

fuels, but also ways ‘to learn to life’ with the consequences of climate changes: • The rising mean outdoor air temperature. • Frequent change of weather conditions: more heat waves, increasing short intense rainfalls, increased wind speeds and frequency of storms. • Increase in smog production caused by temperature rise, causing even more polluted outdoor air.

The consequences are that the outdoor climate our buildings need to be designed for, will be hotter and more humid, and the outdoor air will require to be cleaned before we can use it for ventilation indoors. An air conditioning system most likely is a must and no more a choice. We will stay inside even more, because of the outdoor air quality but also due to the sudden heavy rainfall and wind speeds, leading to a lack of the daylight dosing required for our health. The need for new light designs will increase, moreover the use of flexible and integrated systems

Figure 3 Stressors, factors, causes and effects


is unthinkable. And not only for newly to be designed buildings, but especially for retrofitting of our current building stock. We would like to prevent our buildings to have little airco’s on the facade dominating the city view (Figure 4). Retrofitting has been identified as the most immediate and cost effective mechanism to reduce energy consumption and carbon emissions in the building and construction sector. Moreover, to meet EU energy performance targets, it is necessary to double or triple the current retrofitting rate.

5. Ambition At national, European and world-wide level, it is acknowledged that a healthy and comfortable indoor environment is important for the quality of life, now and in the future. The architect will need to have a more than ever coordinating role in this approach as the overall systems engineer, with a basic multidisciplinary knowledge and integrating capabilities. This new role requires a multi-disciplinary educational program with strong cooperation within and outside of the university. The development of an integrated approach towards risk assessment of indoor environment quality, based on the assumption that the indoor environment is more than the sum of its parts, and that its assessment has to start from human beings rather than benchmarks (of single-dose relationships), will form the basis to realize this ambition.  

Figure 4. A view of an air conditioned building in a hot and humid climate downtown Hong Kong.

The challenge of today lies in the accomplishment of sustainable and low-energy built environment and at the same time a healthy and comfortable built environment. This emerging fact, requires a multidisciplinary interactive top-down approach to facilitate the (re)design, construction, maintenance and operation of an indoor environment, in which the architect as well as the other stakeholders fulfil a new or different role. The architect as the integrating engineer who is able to optimise all components of a building along with the overall demands and needs, whether this is related to health, comfort or sustainability issues.


References Bluyssen, P.M. (2009) The Indoor Environment Handbook: How to make buildings healthy and comfortable, Taylor & Francis, by Earthscan from Routledge, London, UK. Bluyssen, P.M. (2014) The healthy indoor environment: How to assess occuppants’ wellbeing in buildings, Taylor & Francis, by Earthscan from Routledge, London, UK.


Overcoming Fears of Adaptive Comfort in Design

by Chris Mackey Anyone who has spent time engaging with thermal comfort science knows that most research in the field can be classified into two broad camps of methodology. The first takes as its starting point the notion that thermal comfort is fundamentally tied to the physical laws that govern a human’s energy balance. This energy balance equation is broken down into a number of terms and is validated against the responses of subjects in conditioned “climate chambers” under which all of these physical factors can be tightly-monitored and recorded. The second camp takes as its starting point the notion that comfort is a complex state of mind with a multitude of factors - both physical and social, which make it impossible to estimate with only a physicsbased model. Instead of testing subjects in tightly-monitored climate chambers, this research seeks out building occupants within their daily routine and, frequently, in settings of naturally ventilated or thermally massive buildings that contrast with the climate chamber of the first camp. Instead of an energy balance equation, this methodology uses statistical correlations across thousands of surveys in different climates and cultures to arrive at guidelines for what physical variables are usually acceptable in a given season, climate, and level of adaptive freedom given to occupants. Oftentimes, this is expressed as a correlation between prevailing outdoor temperature and desired indoor temperature given a level of clothing/ventilation flexibility (Figure 1). The leading standards of these first and second camps are the Predicted Mean Vote (PMV) and adaptive models respectively, taking their names from the scale used to 16

poll test subjects in the first and the behavior of occupants in surveys of the second. The implementation of the PMV model in building code predates the adaptive by a decade or two but, since the early 2000’s, both models have accumulated a robust scientific consensus around their relevance and have been codified into international building standards. Yet, despite this seemingly equal footing on which the two standards have been placed, the professional application of the adaptive model has been undeniably small if not nonexistent in most recent building projects. In the author’s own city of Boston, the last decade and a half of a codified U.S. adaptive standard has yielded only one new institutional/ commercial building that uses it 1 and nation-wide surveys still show that an increasing percentage of new homes are equipped with central air conditioning, presupposing a climatechamber-based notion of comfort.2 This has happened in spite of the current popular trends of “green” building that stand to show significant reductions in energy use by flowing an adaptive standard, as well as the fact that adaptive research has proven the PMV model to be a poor estimator of comfort in many cases.3 1 Justin Ries, Mariya Berkolayko, Tristan deBarros, Matthew Pitzer. THE EPICENTER // ARTISTS FOR HUMANITY: CASE STUDY 2007. Northeastern University School of Architecture, 2007. 2 U.S. Energy Information Administration, 2009 Residential Energy Consumption Survey. Release date: August 19, 2011 3 Humphreys, Michael; Nicol, Fergus. The validity of ISO-PMV for predicting comfort votes in every-day thermal environments. Energy and Build-

Chris Mackey is a graduate student at MIT who is currently pursuing a dual degree for a Masters of Architecture and a Masters of Science in Building Technology. With an expected graduation date in Spring 2015, Chris is currently working towards a combined thesis between these degrees, which will focus on thermally adaptive occupant behavior and the design possibilities presented by occupants moving around a space to make themselves comfortable. His work experience has ranged from being a climate researcher at Yale University, to a designer at an architecture firm, to an energy modeler and software developer at a building consulting office. In his free time, Chris is an avid coder and contributor to the Ladybug + Honeybee environmental analysis plugins for grasshopper.

climate-chamber-based notions of comfort, ultimately architects and their clients have the ability to choose for themselves and their personal psychology greatly influences the issue. In the author’s experience of attempting to apply the adaptive model to design projects, it is often useful to link the hesitation to apply the adaptive model to three main fears that must usually be overcome for an architect, client or building science specialist to accept the use of an adaptive model. These are: 1) A fear that the adaptive method incompletely describes the factors that shape comfort. 2) A fear that occupants will not adapt in the way that the standard suggests. 3) A fear that the design strategies undertaken will not be enough to meet the standard. This article discusses the challenges of overcoming these three fears and describes some approaches that the author has found helpful in convincing others to pursue the application of an adaptive method. Figure 1. An adaptive comfort chart showing the correlation between prevailing outdoor temperature and desired indoor temperature. Colors represent hours in the oudtoors of Los Angeles.

While one can blame the failure to adopt the adaptive model on entrenched economic factors, such as the private interests of powerful HVAC and insulation manufacturers that benefit from ings, Volume 34, Issue 6, July 2002, Pages 667–684

The first fear - that the adaptive method incompletely describes comfort - is one that is often echoed by members of the building science community and, to the credit of those who raise the issue, it is not unfounded. The published international adaptive building standards leave out a number of important factors that are known to have a significant effect on comfort. Both the 17

ASHRAE and the ISO standards exclude all effects of humidity, forbid any application of the adaptive method to “mixed-mode” buildings (buildings with both AC and natural ventilation), and do not permit the use of the adaptive model in heated buildings during colder seasons where average outdoor temperatures drop below 10 C. Without the ability to account for humidity or cooling and heating systems, most building science specialists feel too restricted in their use of the standard or find themselves in unnavigable situations of switching back and forth between PMV and adaptive standards. However, if one looks past the present shortcomings in these published standards and towards the scientific literature produced from the adaptive methodology, one usually finds that the research community has agreedupon methods to account for these factors when applying the adaptive method. For example, in the initial development of the ASHRAE Adaptive standard, there was momentum to use the metric of effective temperature (ET) instead of the published dry bulb temperature (DBT), which would have weighted the temperature to account for the effects of humidity. DBT was presumably selected in the end “to make the calculations more accessible to practitioners,” which seems suspicious given the large complexity of already existing PMV calculations.4 Suspicions aside, knowledge of ET is useful in situations where there is a concern about humidity, since one can substitute the DBT in the adaptive calculations to get a rough approximation of how humidity might affect the situation. To account for the effects of running cooling or heating systems, there are a large number of adaptive comfort surveys that have been conducted in tightly conditioned spaces, many of which were initially used to show that the adaptive methodology did not contradict the findings of PMV in cases of conditioned buildings. Plotting the results of conditioned spaces in relation to naturally ventilated ones (Figure 2), one realizes that adaptive model is defined not by the rules of a published standard as much as it 4 Humphreys, Michael; Nicol, Fergus. The validity of ISO-PMV for predicting comfort votes in every-day thermal environments. Energy and Buildings, Volume 34, Issue 6, July 2002, Pages 667–684


is by the methodology of using data from real building surveys, which can be done regardless of monthly outdoor temperature or the presence of a heating/cooling system. Furthermore, the juxtaposition of correlations for naturally ventilated and cooled buildings gives a sense of what to expect for a mixed-mode building – a case which neither the published adaptive or PMV standards do a suitable job of explaining. Finally, while at the end of a project’s documentation, one might need to express comfort of a heated or cooled building in PMV to meet code, one does not necessarily have to do so during design and can instead use the heated/cooled correlations as a guide until they are ready for the acrobatics of switching between a PMV and adaptive calculation. Initially, it might seem that this post-processing of adaptive guides into PMV might be a dangerous assumption, but if one is given the ability to change the clothing and metabolic rate inputs of the PMV model, there is usually enough freedom to show that the PMV standard will still be met if this adaptive behavior of the occupants is accounted for. This brings us to the next fear that is often difficult to overcome: a fear that occupants will not adapt in the way that the standard suggests. In order to address this, it is often necessary to point out the underlying assumptions in the PMV model, which, upon close inspection, show that people must necessarily adapt to be comfortable. Nowhere is this fact more apparent than in the PMV model’s recognition that one can never have a percentage of people dissatisfied (PPD) that is less than 4%. This fact is intensified by the common building practice of only aiming to keep 90% of people comfortable. One can interpret this with the usual saying “you can’t make everyone happy,” but when one thinks about what likely happens to these marginalized 4-10% of people in real buildings, one imagines that they likely compensate by adjusting their clothing, adjusting their metabolic rate, or changing their immediate environment with strategies such as the pulling of blinds. The power of the first adaptive strategy is illustrated in the PMV model itself if one traces the PMV “comfort polygon” commonly seen on the psychometric chart from “shorts and a T-shirt” (0.4 clo) to “a sweater and jeans” (1.2 clo). A similar plotting can be done with the metabolic rate from “relaxed seated” (1.0 met) to

Figure 2. Top - Different correlations for a building that is naturally ventilated (left) and air conditioned (right) in Los Angeles. Bottom - An adaptive comfort correlation for heating is used to help determine the thermostat temperature in a New York apartment.


“typing or sitting with occasional movement� (1.2 met). Taken together, the two personal strategies offer a very wide range of adaptation that is typically not exploited in the application of the PMV model (Figure 3).5 Being aware of the powerful effects of clothing and metabolic rate can go a long way to assuaging fears about the range of comfort referenced in the adaptive model. Still, it does not explain all conditions of the adaptive model and particularly those that are achieved as a result of the psychological difference between a warm sealed room and a well-ventilated room at the same temperature. For this, it is important to recognize an important assumption in the polling of participants in the original PMV studies, which only asked individuals to report if they felt warm, cold, or nothing at all and did not ask them the much more important question of whether their sensation of warmth or cold was acceptable to them. Admittedly, the assumption that a warm person in a climate chamber is uncomfortable may seem safe but, importantly, several adaptive studies have reported survey participants claiming that they felt warm but this warmth was perfectly tolerable, particularly if the space was naturally ventilated.6 Overcoming these first two fears might get a design team or client on board with the use of an adaptive approach but the commitment is usually not solidified until people are given a very clear means of knowing that their design strategies will succeed in meeting the standard. Admittedly, this last fear can be the most difficult to overcome since a successful application of an adaptive model requires a good design intuition about the thermodynamics of mass and heat storage, which can be a challenge to acquire without previous experience designing passive buildings. To worsen the problem, many building energy simulation tools that might otherwise help strengthen design intuition are not geared towards the modeling of passive design strategies needed for the application of the adaptive 5 de Dear, R. ; Akimoto, T.; Arens, E.; Brager, G.; Candido, C.; Cheong, K.; Li, B.; Nishihara, N.; Sekhar, S.; Tanabe, S.; Toftum, J.; Zhang, H.; Zhu, Y. Progress in thermal comfort research over the last twenty years. Indoor Air 2013; 23: 442–461. 6 Hoyt Tyler, Schiavon Stefano, Piccioli Alberto, Moon Dustin, and Steinfeld Kyle, 2013, CBE Thermal Comfort Tool. Center for the Built Environment, University of California Berkeley,


Figure 3. The range of adpatability provided by typical variations of clothing (top), metabolic rate (middle) and both clothing + met rate together (bottom).

model, including complex natural ventilation schemes, interior management of solar gains, and high thermal mass cases. Even if an engine can accurately model these phenomena, the results of the model are usually never synthesized in a visualization that a designer can use to understand both the full spatial and temporal range of adaptability provided through differences in interior microclimate. Still, there is usually enough information coming out of the more advanced energy models to create high enough resolution maps of interior temperature to grant confidence that an adaptive strategy will work. An approach for generating such maps was assembled by the author from four main inputs that are obtainable from an EnergyPlus simulation and its corresponding weather file: surface temperature, air

Figure 4. Indoor microclimate maps are assembled from the outputs of an Ener- gyPlus simulation of a room.

temperature, solar radiation that can fall directly onto occupants, and air stratification (Figure 4).7 The maps address the difficult issue that, in order to meet the adaptive standard, it is usually not possible to get an entire space within the target range but, so 7 Menchaca, A. Study of Airflow and Thermal Stratification in Naturally Ventilated Rooms. Submitted to the MIT Department of Mechanical Engineering in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Mechanical Engineering, May 11 th 2012.

long as some part of the space meets the standard, occupants can adapt by moving to the more comfortable parts of the building. This makes the particular interior microclimatic layout essential to meeting the standard in a way that is not simply a matter of good ventilation but also good spatial arrangement of thermal mass in relation to solar heat and nighttime coolness (Figure 5). Finally, by showing the spatial distribution of


Figure 5. In a fully-conditioned space, the arrangement of interior program and rooms is not so important as most interior space is comfortable. However, once a HVAC system is removed and one tries to keep a space cool with natural venti- lation, this arrangement becomes pivotal to ensuring comfort.

temperature, the maps also assist with the placing of indoor program to help ensure that occupants are in these comfortable spaces at appropriate hours (Figure 6). While the strategies offered here are by no means a solution to the issues of adopting adaptive comfort in practice, they constitute a framework for initially tackling the fears that appear to hold back much of the profession today. The challenge of 22

addressing these fears may seem like a monumental task but it is important to remember that most of architectural history is on the side of adaptive comfort with thermally desirable conditions emerging in passive vernacular constructions only after centuries of trial and error. With today’s ability to undergo this process of trial and error in a computational environment much faster than history ever could, it should hopefully not be long before modern adaptive, passive vernaculars emerge.

All images produced with this article were made with opensource tools coded by the author. If interested in applying them on your own projects, you can download them at http://www.

Figure 6. Program activated at different times of day is placed in relation to comfortable microclimates. As the majority of the apartment is night flushed from 12AM - 9AM, sleeping and bathing areas remain sealed and warm. In the heat of the mid-day, occupants retrat to the inward cool ant thermally massive office space. At night, as the heat of the day subsides, occupants reemerge to cooking areas and the still comfort- able office space transforms into an entertainment space.

8 Menchaca, A. Study of Airflow and Thermal Stratification in Naturally Ventilated Rooms. Submitted to the MIT Department of Mechanical Engineering in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Mechanical Engineering, May 11 th 2012.


Light in design

Interview with Erik van Eck

Interview by Reinier Scholten and Marc Nicolaï. On the 7th of January 2015 RuMoer visited Broekbakema to interview Erik van Eck about daylight in design and several recent projects that are related to this topic.

What is your view on light in design? Broekbakema grew into a large office based on a tradition of modernist design. That tradition, with the three keywords light, air and space, has always held an important position in the architecture of Broek and Bakema and now Broekbakema, if somewhat adapted to the architecture and fashion of today. In terms of light, air and space the Van Nelle factory is a beautiful example. If you look at how deep daylight can fall into the building simply because of the high floor height. When you’re talking about development, you can see that the moderns of that time were very involved with those words. This resulted in a lot of glass surfaces in buildings, but this brought with it that rooms could become very hot or cold. Of course today we’re dealing with far higher quality glass that allows for far better insulation and keeps out the sun for an important part. But that isn’t enough. That’s why we always try to design according to form follows climate. Form follows function was a common phrase back in those days but now we look more at climate. Climate inside also means comfort. How can we create a good working environment where all those things come together in a balanced way? That’s what we’re always searching for. For each user this is different: an educational institution is different from a high quality laboratory environment. 24

Van Nelle factory: the warehouses in front with large windows house the Broekbakema office.

The interior of one of the warehouses housing the Broekbakema office.

Erik van Eck, MArch, is Architect director and member of the management team at Broekbakema architects. Broekbakema is an architecture firm located in one of the old warehouses of the Van Nelle factory in Rotterdam. The founders of Broekbakema, Brinkman and Van der Vlugt, were responsible for the design of the Van Nelle factory and many other important Dutch architecture gems throughout the 20th century. All imagery in this article courtesy of Broekbakema. For more information visit: I myself am in favour of generic buildings as a solution. Especially if you look at the high rate of development, that makes things obsolete by the time you’ve thought of them. So you have to make things that are timeless. Make the main load bearing structure so that it can take anything. Make it timeless, robust, and so that it can handle any kind of use. Even though it isn’t asked of us, we think about how a building can be used by other users as well. That’s something that always occupies our thoughts. We think it’s important to have a good look at the future, free from the daily practice of working for clients. We try to do this with our projects, but there the ambitions are usually not in line with such a view. The framework for what is allowed is usually very confined. That is where the power of architecture lies. To get as much out of it as possible.

connect to each other and the big educational facilities and parking spaces are located. Above that is the campus level, the human level, where all the campus buildings stand as solitary buildings. It’s a building with rather deep floors of 18 meters that can be flexibly filled in with the required program. This was developed further into the components so that it really would be easy to adjust the interior lay-out. On the one hand it is a thick and compact building to be sustainable energy wise. On the other hand the atrium allows the interior facades to act as actual facades.

The windesheim was built for education but it is a good example of a generic building: flexible in its setup and would easily allow a different use. The facade appears more transparent than it really is. It’s a composite facade, reasonably light and with a high insulation value. The thicker you make those walls, the less light falls through. So the question was how to get enough light into the building.

When I made my first atrium building I got to hear that everyone ended up preferring to sit at the exterior facade. I think that if you make the atrium interesting enough, it can become a lively place, a place where you can have a cross-over and come to new innovations by working together. The more you work together, the more chance there is for innovation. I think that these kind of spaces are especially suited for this. Of course there is also space for tranquillity and concentration, but this one is for encounters. The atrium is quite high, but by making floors that stick out and placing working spaces there and also by making floors open up to the atrium it becomes very lively.

If you look at the setup of the entire building then you can see we introduced a second ground level. On the lower level the buildings

There are two departments in this building. By choosing a splitlevel division, that has you go up half a floor each time you cross

How was this applied in the Windesheim school building X?


Interior view of Building X, showing the central atrium.

Windesheim Building X, housing both an economics and journalism department.


Interior view of the composite facade structure.

the atrium, you repeatedly see what is happening on either side of the building. This makes it fun. I think this will also allow you to experience being part of a community. Personally I think it’s pleasant when you can see what is going on in a building and don’t get the feeling you’re the only one inside. People cross over in the atrium. The restaurant reaches into the atrium. There are free study places in the atrium. All of this makes for a lively environment.

made up of laboratories. We chose for an entry on the level above it so you actually enter through the heart of the building. After this you only have to go down one level or two up. Next we came up with making some large openings that fully connect the laboratories with the atrium. This creates a flow throughout the space and makes it more articulate. Together with the bridge this has resulted in the atrium not being experienced as too big, but as very pleasant.

Being in contact with the outside also adds to the experience of a building. You can also see this in our own office. The working spaces deeper into the building still get a view to the outside and enough sunlight from the roof light in the atrium.

Just as with Building X we made deep wings that are covered in glass on both sides that make them very open and create a nice atmosphere. The roof light above makes it so that everything bordering on the atrium is supplied with enough daylight. A walkabout was added that allows people to always move into the atrium from their department. With the addition of open stairways people are always visible when moving around the atrium. It is a very open building, but there is also a shielded room where the researchers can brainstorm with each other undisturbed. A closed off drum shape where they can lock the door and not be disturbed by anyone. The building actually consists of two parts: an office and a laboratory. As a whole the building is square shaped, with bits cut out that allow for views of the outside world and vice versa from the outside world into the heart of the building. This also cuts up the large building into smaller pieces. We raised the ground level with green slopes that cover the laboratories and connects all the elements. Light can enter some parts of the laboratories through translucent panels creating a pleasant environment. In most of the building we brought down the general lighting levels and added workplace lighting that can be adjusted by the users.

What kind of response did you get from the users? The school has had a lot more students apply since it moved into this building. On the other hand we hear about some people who don’t like the transparency and always being visible. So of course there also have to be places with more intimacy where you can shut yourself off from the rest of the world. These were also realised in the building.

What were the considerations when designing the new DSM building? DSM requested that we bring several departments together and create a synergy between them. This we did by making a big building with an atrium that is divided in two by a bridge. The building has four levels of which the lower level is completely

“Personally I think it’s pleasant when you can see what is going on in a building and don’t get the feeling you’re the only one inside.”


Interior view of the central atrium of the DSM R&D centre. (photo: Pieter Kamp)

Exterior view of the DSM R&D centre. (photo: Ronald Zijlstra)


The pond on the laboratory level. (photo: Pieter Kamp)

Section view of the proposed Energy Academy

Exterior view of the proposed Energy Academy

Experimental setup of the rooftop PV formation concept.


Interior view of the central atrium of the proposed Energy Academy

What did DSM think of the initial plan? They were afraid that the laboratory area would feel like a basement. So we placed a pond in the atrium on the laboratory level to create a quality environment and it is experienced as such. An atrium isn’t a guarantee that the building will be pleasant. You have to think about the qualities it adds to the building. In this case the articulation, different levels, the plants and daylight make it work.

Any specific daylight considerations? We made the floor height 3 meters, instead of the minimum 2.60 30

meters to allow more light to enter the floors. On the exterior the parapets stick out to act as sunshades.

Were there any special requirements for the labs? Designing the laboratories was a very involved process. With every laboratory department we had beamer sessions to discuss the best way to shape their environment. Their perspective really focussed on the primary process and we were able to give more insight into the spatial implications. In this project we got to do everything, the building, the interior, the landscape... it was fantastic. Despite a strict budget we were able to create something beautiful.

Architect Sander Veenstra joined us to talk about the Energy Academy Broekbakema is designing for the Zernike Campus in Groningen.

What is the Energy Academy? It’s an education building with offices and laboratories. The Energy Academy Europe is an institute that studies all forms of sustainable development for the built environment. The building is quite an ambitious project. One of the goals is zero-emission. Another is attaining the BREEAM outstanding label. First we had a look at where all the energy goes into such a building. It became obvious that lighting is a significant part of the buidling’s energy consumption. We also set our self the goal that 100% of the energy had to be generated on building level. That’s very complicated, but we’re well underway. Most of it we want to generate with PV cells on the roof. Other considerations were made for cooling and heating with air. An insulated winter garden creates a thermal buffer on the south side, allowing people to open their windows throughout the year. Together with a whole system that allows natural ventilation throughout the buidling through a tunnel system below the building we hope to reduce mechanical ventilation as much as possible.

panel, but as a whole this solution is still favourable, allowing for a good balance between energy generation and daylight entry. This formation also allows for shielding the roof from solar heat when the sun is low. We also thought about how the facade had to both let daylight in and keep out solar heat. Most of the direct sunlight during peak

hours is blocked by the external vertical fins that keep out the sunlight when the sun is low. However there still is about 50% window coverage allowing a lot of daylight to enter the building through the facades.

What role has daylight played in the design for the Energy Academy? This building will also have an atrium with daylight coming in from the top. However we also want to harvest as much energy as we can with PV panels. So we had to find an ideal balance that came down to about 60% PV and 40% open to daylight. So we got to thinking: how can we position the panels in such a way that we can win back as much as we can? Our solution was to position the panels under an gradient, starting with a flat panel and with each following panel standing up further. If you were to place the panels horizontally they would cover the entire roof, but with this formation we were able to create more roof surface. With this method the PV panels deliver less energy per


Light in research

Visual comfort study in classrooms

by Anne Leeuw and Alois Knol Daylight is important for schools regarding energy usage and the health of teachers and students. The ‘Programma van eisen voor Frisse scholen’ (requirements for healthy schools) sets a number of requirements for the indoor environment. For the ‘Prins Florisschool’, an elementary school in Papendrecht, the current daylight situation has been studied and tested with these requirements. For this research measurements, simulations and questionnaires have been used.

Table 1. Requirements base upon ‘Programma van eisen voor Frisse scholen’

Requirements In our research we investigated certain requirements based upon the ‘Programma van eisen voor Frisse scholen’. We measured the illuminance levels and the daylight factor using a lux meter. The daylight factor is the ratio between the illumination of the sky (free field) and the working area. The evenness index (g) is the ratio between the minimal illuminance of the working are (Emin[lux]) and the mean illuminance (Egem[lux]). In addition to the ‘Programma van eisen voor Frisse scholen’ the DGP (Daylight Glare Probability) and the contrast have been added to the requirements. The human line of sight is approximately 180 degrees. However, the quality is not spread evenly over this field. This means that disturbing visuals are not always perceived the same. To determine if light is disturbing the aspect of contrast is analysed. The areas that can be analysed are the ergorama and 32

Figure 1. Human field of sight (Illuminating Engineering Society of North America, 1984)

For the course Technoledge - Climate Design, two students from the TUDelft, Anne Leeuw and Alois Knol, performed a study on the light comfort in an elementary school in Papendrecht, in the Autumn of 2014.

the panorama. These areas have a radius of 30 and 60 degrees. The bigger the field, the bigger the contrast can be, according to the literature. If the contrast is high, there is a chance of annoying reflections or glare. It is possible to determine the probability of the occurrence of glare, depending on the illuminance (of daylight), measured in the vertical field. This is called the Daylight Glare Probability (DGP).

Measurements Two classrooms were used to measure the light conditions. One at the west side of the school and one at the east side. The classrooms are located on the first floor and are a good representation for all the classrooms in the school. The reason we investigated two classrooms on both sides of the school is the fact that orientation is also important for visual comfort. In the eastern classroom there is more and more frequent direct sunlight. In the western classroom the sun enters at other moments of the day and also the angle is different. The following methods were used in this investigation: measurements with a luminance camera, measurements with a lux meter, computer simulations and a questionnaire. The digital SLR camera from Canon with a fish-eye lens is used to measure the luminance (cd) in the vertical plane. The fisheye lens approximately represents the human field of sight.

Figure 2. Orientation of both of the classrooms


The camera that is being used for the luminance photographs is calibrated so it can be used together with the LMK Mobile Advanced software from TechnoTeam to map the luminance. The software maps the photograph to certain colours which all represent a different amount of luminance. The scale goes from black (dark) to blue, green, red, yellow and white (bright/very bright). These colours represent different values of cd/m2, or: candela per square meter. To measure the daylight factor (without using simulations) we need the illuminance in the free field. The illuminance that is measured close to the window is influenced by the roof and the window frames. The surrounding buildings will also increase the reflections. To take this into account we will need a certain correction. This correction for example takes into account the reflectivity of the materials and the surrounding structures/ houses.

Results In this investigation the daylight factor is determined with measurements on 6 October, 2014, while the complete sky was covered with clouds. To check the illuminance of the sky, the illuminance is measured from different locations in the school. The daylight factors are measured using the lux meter. This lux meter is placed at different positions in the classroom. Figure

Figure 3. Figure from the LMK software including the scale


Figure 4. Measured daylight factors and requirements

4 shows a summary of the measured values. After the calculation of the daylight factors on every measured point, the mean value is determined. For this type of classroom the average value is 2,3%. This is 0,7% lower than the required value (for lowest acceptable category, category C). In figure 4 can be seen that only three of the measured points reach the required level. According to the ‘Programma van eisen voor Frisse scholen’ the illuminance on work surface height should be at least 300 lux to be acceptable (category C). For category B the illuminance should be at least 500 lux and for category A this is the same, but the teacher’s working area should have an illuminance of 750 lux of which 250 as an extra controllable light source. In figure 5 it is clearly visible that the requirements for category B are not being met. However, the requirements for category C are being met on almost every measurement point. The reason for the low values at point B2 is that the lights on that location are always switched off, so they were also switched off during the measurement. To determine the luminous intensity contrast in the field of view the levels are determined using luminance photographs. For different positions the contrasts are measured. The contrast values are measured both for the panorama and the ergorama.

classroom. The daylight factor will become 4,17%. The wooden slats on the façade should be removed for more light inside the classroom. Using this improvement the daylight factor will become 4,58%. There should be windows in the ceiling. This way there will be more light further away from the windows and the daylight factor will become 5,35%. To improve the illuminance and the energy usage the current fixtures could be equipped with new lightbulbs. A problem using this improvement can be that the lights can become too bright. Another option is to install new fixtures so they will spread the light more evenly. The best option however would be to install new fixtures accompanied by a new control system so the lights can be adjusted according to the preferences of the users. Figure 5. Measured illuminance and requirements

In figure 6 the normal light situation is shows. The lights are on and sky is spreading homogenous light. The photos are taken on the same day as the measurements of the lux levels. What stands out is the fact that there isn’t that much glare when the sky is homogenous. Nevertheless the contrasts are quite high. From the results follows that there is glare. This glare can be caused by reflections from tables or the lights in the classroom. From the photograph it is visible that the fixtures are the brightest followed by the light coming in through the windows.

To decrease the amount of glare while maintaining the view out of the windows we advised the following improvements as options: Awnings instead of the current sunscreens. This will make sure that light can’t come from the sides anymore but will not add extra elements directly in the line of sight. An alternative is to replace the current roller blinds, which are always closed, with a transparent screen. These screens will still decrease annoying

Improvements To be able to give a good advice on how to improve the current situation, the current situation and the possible improvements are simulated. The simulations are done in the 3D modelling software Rhinoceros and the plugin Diva Radiance. The classrooms are modelled in Rhinocerous (figure 7) and then Diva Radiance is used to calculate certain values. The possible improvements are given per category and from small/easy to big/hard executable: To improve the daylight factor the ceilings could be painted in a lighter colour so the light will spread better through the

Figure 6. Normal light situation


Figure 7. Input for the simulation model which is used in Diva Radiance

daylight/glare but will make it possible to look outside. The best options however would be to remove the current sunscreens and roller blinds and completely replace them by screens on the outside. Conclusions While the investigated school currently does not reach the minimal recommended values mentioned in the ‘Programma van eisen voor Frisse scholen’ there are quite a lot of possibilities to improve the situation. In table 2 the measured and the potential values are shown. As can be seen in this table the school can potentially reach category A for some of the measured values. 36

Table 2. Measured and potential values

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Creating acoustic comfort in noisy environments

by ir. Marten Valk and ir. Bastiaan Beerens

User experience of a building is important to building physicists. The qualification of a room or building is largely determined by the level of comfort experienced by the end user of a building. This includes the acoustic comfort of a building, especially the acoustic comfort in a crowded room or environment. This issue commonly arises in various situations like in open plan offices, in restaurants and at big crowded events. Deerns has come up with an innovative solution.

Adaptation leads to creation The desire for acoustic comfort in a crowded environment arose during the real estate event ‘Provada’ in Amsterdam in 2013. During roundtable discussions at this busy event the participants had difficulties understanding each other due to low speech intelligibility. As a result, people were raising their voices so they could be understood. The acoustic consultants of Deerns were asked to come up with a solution to this problem. This was the start of the innovative path Deerns took with the development of a solution which would eventually be known as the ‘Silent Cube’. Innovation is not typical of the building industry. People rely on proven concepts. New, innovative ideas are often not received with much enthusiasm. Risks are too high – or so it seems – which can be the reason not to choose these solutions but to stick to the known, proven concepts. That is a pity, because the world changes and so does the use of buildings. Densely 38

populated areas, larger and more crowded events, and open office plans are some examples. If we adapt to the changes around us, we can create a new and improved built environment. Back to our question. The goal was to come up with an innovative solution to enable normal conversations in a situation with a high background noise level, and demonstrate this solution at the next year’s Provada event. During the first brainstorm sessions the phenomenon ‘noise-cancelling’ was discussed, a technique which is used, for example, in some types of headphones. The translation of this technology to a (headset-less) solution was too big a step to take in such a short time, mainly due to the dynamic aspect of the background noise level at the event. It was soon recognized that the solution had to be found in the use of building materials and/or constructions. The goal was to create an enclosed modular meeting facility with good acoustic properties and no sound nuisance from outside. The space needed to be enclosed because of the sound isolation requirements, but this also means the space needed ventilation to supply fresh air for air quality and thermal comfort. The visual comfort is another aspect to take into account. To realize this goal Deerns worked together with different partners. It was encouraging to see that so many parties were willing to participate. Amongst them was Saint Gobain, one of the biggest suppliers of glass in the world. They already worked on a prototype of a temporary meeting space (comparable withthe Deerns concept) but the thermal and visual comfort, as well as

Marten Valk (1981, on the right) is consultant at Deerns in the field of building physics, acoustics and fire safety. He studied at this faculty and graduated within section of building physics on the acoustics of the new Conservatory of Amsterdam. It is his mission to make a considerable contribution to the continuous improvement and innovation of sensory comfort experience in the built environment which ultimately results in less consumption of energy. Bastiaan Beerens (1982) is an all-round building physicist, specialized in building and room acoustics. He has studied at the faculty of Architecture, Building and Planning at the Technical University in Eindhoven, and is now doing research and consultancy work in the field of building physics and acoustics at Deerns.

the air quality, was not taken into account. Deerns and Saint Gobain combined their knowledge and worked together on an integral solution. An adaptation in the crowded environment, which led to the creation of the Silent Cube concept.

Innovation and technique The Silent Cube is made out of structural glazing: glass partitions without frames. The glass used has several features. One of the main features is the sound isolation of the glass. The sound pressure level (SPL) of an average conversation is approximately 65 dB(A). Sometimes, the SPL at an average day at the real estate event lies around 75 dB(A). This means the background noise level was much higher than the conversation level, causing a reduction of the speech intelligibility. The challenge is to provide sufficient sound isolation while taking other aspects, like fresh air supply and views, into account as well. To meet the sound isolation requirement acoustical laminated glass was used, creating a sound isolation (DnT,A) of 32 dB for the whole Silent Cube. This means the average sound pressure level in the Silent Cube, caused by the present ambient sound level of the Provada event outside the Silent Cube (70 – 75 dB(A)), will be around 40 dB(A). Taking into account that the sound pressure level of an average conversation is approximately 65 dB(A), this means that the conversations in the Silent Cube will not be disturbed by the high sound level outside the Cube.

To demonstrate the difference in sound pressure level inside and outside the Silent Cube, two iPads were installed. A sound level measuring app visualized the difference at the stand. To provide an acoustic environment in the Silent Cube suitable for meetings, sound absorbing elements were added in the walls and the ceiling. In addition, the floor finish consists of a carpet with good sound absorbing quality. This resulted in an average reverberation time of 0,6 seconds, very sufficient for meeting spaces. The design reverberation time was confirmed by doing measurements on site. To provide fresh air and prevent warming-up of the room, ventilation facilities had to be realized. To provide ventilation, an air extraction fan was chosen to be placed on the roof, connected with an exhaust grille in the ceiling. Sound damping was provided by using silencers in between. The sound level caused by the fan does not exceed 40 dB(A). Because of the sound isolation requirements, it was not possible to apply air inlets in the walls or door. Therefore, the fresh air supply was created by a plenum under the floor which is used as ‘air duct’. Sound damping was provided by adding sound absorbing materials in the floor plenum. The air inlet grills were located at the floor edge on the other side of the stand.


Figure 1. The Silent Cube. Image courtesy by Ric Isarin.

The laminated glass not only creates acoustic comfort, it also maintains the visual relation with the rest of the event. As an extra feature, privacy can be created by using Privalite: glass partitions which can be made translucent.

Further research With many enthusiastic visitors and temporary users, the Silent Cube prototype proved to be a success at the 2014 Provada Event. It is the perfect solution as a temporary meeting facility


at events. Besides large events the Silent Cube can be used in open plan offices as well. Deerns is currently improving the development of the Silent Cube, in a collaboration with Saint Gobain, Zwarts en Jansma Architects and Bussman (specialist in temporary housing). The possible integration of Phase Changing Materials (PCM) is another aspect to be included in this development.

For the acoustic aspects, Deerns is currently doing research to optimize the room acoustics in the Silent Cube. The prototype consists of vertical walls, standing parallel opposite to each other. This can cause unwanted echoes and flutter. With the support of a graduate student from the HZ University of Applied Sciences, Deerns is looking for the optimal lay-out configuration of the Silent Cube. The question is how to optimize the room acoustics of a meeting room which largely consists of glass partitions. With a study of the influence of the geometry and the use of materials, and by using 3D acoustic simulation models to accurately determine this influence, Deerns is improving the design and the acoustic comfort of the Silent Cube. Deerns has done measurements of the reverberation time of the prototype, to get the ‘acoustic fingerprint’ of the room. This data is used for a 3D acoustic simulation model, to create a ‘digital copy’ of the room. This digital copy is used as the basis of the study of the influence of the geometry and the use of materials. In this study, different configurations of material use are assessed. To reduce unwanted echoes and flutter, the influence of slightly tilted surfaces in different configurations is examined.

The collaboration between Deerns consulting engineers and the various companies and educational institutions has paid off, and Deerns strives to continue these collaborations in the future.

Future Deerns can look back to a successful process of development of the Silent Cube. The collaboration between Deerns and different partners has resulted in the Silent Cube as a solution for people who want to have a meeting space wherever needed. The need for acoustic comfort in a crowded environment has been met successfully. And this is only the beginning. Further development of the Silent Cube concept is in progress at the time of writing this article. Improvements of the (acoustic) comfort of the Silent Cube are at hand. Deerns aims to be innovative and stay one step ahead. For this a good cooperation is needed between creative, innovative people, and people who bring ideas to life using technical knowhow and sober analysis. This means manufacturable, practical, cost-efficient and technical/conceptual sustainable solutions. Successful innovation depends not only on practical skills and knowledge, but passion, courage and entrepreneurship as well.


The design of a multifunctional exhibition hall When acoustics integrate with the structural design

by ir. Lotte Baerends Exhibition halls are buildings that are typically used or rented for a few days, but most of the time these type of halls are vacant. By adding functionality the usage rate of these buildings can be increased. A logical choice to add to the building would be acoustic functions, as they often require a large floor surface, e.g. music festivals. Also structure of a large exhibition hall with a preferably free floorplan requires a characteristic structural design. The integration of the acoustic functionality and structural demand has led to the following research question: “What are the characteristics of a multifunctional exhibition hall of which the structural design is integrated with the variable acoustical design and of which the acoustic properties are used as decisive factors in the visual appearance of the design?� Using computer analysis, literature studies and case-studies a conceptual design was developed.

Requirements As a foundation for the design the existing exhibition complex WTC expo Leeuwarden was used. The new hall replaces an existing hall and thus it has to be an addition to the functionality of the building, rather than a replacement. This has been done by not creating a hall only functional as an exhibition hall but as a concert (amplified music) hall, acoustical music hall and speech hall as well. The acoustical music hall and speech hall have to comply to very specific acoustical demands, while the amplified sound in the concert hall make it easier to comply to the 42

Figure 1. Impression of the hall in different positions

Lotte Baerends (23) started her education to become an engineer at the faculty of architecture of the TU Delft in 2009. She is planning to graduate from the mastertrack ‘Building Technology’ in January 2015. Early in the course it became clear to her that she had a particular interest in detailing and the technical aspects of the designing process. During her graduation these aspects also played an important role. As her graduation project she developed a space with variable dynamics by making the size and shape of the design dynamic, using an ingenious architectural folding system.

0,8 seconds. The clarity is the ratio of early arriving sound and late arriving sound. A speech related function requires a higher clarity because of the intelligibility. For an acoustic music hall this boundary is set at 80 ms (C80), the clarity should have a value between -3,0 and 0,0 dB. A speech related function the boundary is set at 50 ms (C50)and should have a value higher than 1,5 dB3. These values have been determined assuming these two halls have similar dimensions: 1.710 m².


Figure 2. Impressions of the hall interior in different positions: 75 meter (upper picture) and 150 meter (lower picture)

acoustical demands. Therefore focussed was on the acoustical music and speech hall. Both of these halls have different demands for reverberation time and clarity. Reverberation can be defined as the time elapsed from when the sound source is disabled until the sound pressure level (SPL) has lowered 60 dB1. For the acoustic music hall this should be between 2,0 and 2,3 seconds2. For a speech related function this should be lower than

To minimize the amount of materials needed for the structure the aim is to integrate the acoustical shape and materialisation with the structural design. In the development the acoustics were decisive. Sound waves, frequencies, reflections are all related and contribute to the experience of the audience in a concert hall or auditorium. Besides the reverberation time and clarity another important factor is the envelopment. Envelopment depends on the sound direction as perceived by the receiver. A larger variety of sound directions results in a better envelopment, which is desirable for music related functions. The current shapes of concert halls are derived from optimization of either view or envelopment, but not both. The rectangular and hexagonal shaped concert halls are the most successful in combining a good view and envelopment.


Based on this knowledge a rectangular design was used as a basis for the design. The shape of the hall is based on folding techniques. By folding the roof or wall, a surface is created which can diffuse the lateral sound reflections and create a better envelopment. The angle of the folds and direction of the surfaces strongly influences the envelopment. The diffusion is best when the folding lines are parallel to the main sound direction. Another possibility, which arises when using folding patterns, is the reduction in size of the hall. The building can be compressed and expanded and take on different sizes as a result of the folding pattern. When the floor surface of the building changes, the angle of the roof changes as well as a result of the angles in the folding pattern. A movable building solves the difference in floor surfaces between the different functions and creates an intriguing shape. The amount of unneeded area can be minimized, which reduces the climate demand. The detailing of the building becomes more difficult as the building has to be watertight and insulated (sound and thermal insulation). When the supports are fixed in place the folded shape also results in a structurally strong shape, which is able to reach a span of 85 meters. The span of the building is a constant. The height and the length of the building can change. The exhibition hall is 150 meters long with a height of 26 meters, the concert (amplified music) hall has a length of 75 meters and a height of 15,5 meters. The smallest position is the acoustic music hall with a length of 40 meters and a height of 15 meters.

composite panels. Glass fibre reinforced plastic is a lightweight material with high tensile and compressive strength and was used to create the structural shell with a thickness of 17 mm. Due to its poor acoustical insulating properties the material rigid polystyrene foam, which is a common material in sandwich panels, was not used as insulating material on the inside of the panel. Instead a hard rock wool, which has a good sound absorption property, was used. Calculations have shown that a thickness of 260 mm was needed to reach a Rc-value of 6 m²K/W. This results in a theoretical Rw-value (sound resistance) of 97 dB. This relatively high sound resistance value results in a sound absorption coefficient of 0% for all frequencies, when analysing the room acoustics. Meaning the only highly absorbent surface in the room is the audience.

Detailing The panels are connected using a longitudinal composite fabric hinge, which is easy to fix on the building site. The hinge does not have any thermal insulation, therefore profiles are added to the outside of the structure. Flexible soft mineral wool insulation

Structure The foldable dynamic exterior fits the changing function of the building and results in a dynamic interior as well. To create the dynamic exterior a pattern combining X- and V-folds was used. This pattern is mirrored over the centre of the hall to form the second part, resulting in a three-hinged span. Research shows that, without any additions to the structural design, the best envelopment, clarity and reverberation is reached by using 16 of the folded ribs, which have a width of 10 meter when they are unfolded. The structure has the same shape as the interior and consists of 44

Figure 3. The folding system

Figure 5. Detail of the roof connection


Figure 6. Detail of the floor connection


slabs with a rubber film on both sides are fixed in the profiles. These insulation slabs minimize sound leakages, thermal bridges and assure water tightening. Besides the walls and roof which are a part of the folding pattern, there are also side walls that have to change shape because of the changing angle between the folding wall and roof. To close off the wall large triangular composite panels are sliding over each other. When the structure changes shape, the wall is able to shift shape as well.

Variable acoustic design The acoustical music hall and the speech hall are designed to be the smallest configuration of the hall. In this position the hall is divided by an internal wall so a music hall and a foyer is created, the dimensions of the hall are 40 by 42,5 meter. Both functions have the same tribune, which is enough for 1.801 visitors. The stage is 7 meters deep and has a width of 32 meter, which is enough for an orchestra with 100 musicians. The transformation between the acoustic music hall and speech hall is achieved by flipping the panels of the internal wall. This wall consists of Sonico panels, developed for acoustical purposes. These panels function as doors at some locations, but their main purpose is to contribute to the acoustical design, as one side of the panels is perforated and functions as an absorbing surface while the other side reflects most of the sound. Panels can be added to the side of the entrance doors to absorb sound as well. When the hall is used for a speech related function a reflector is placed above the stage, to reflect sound more directly rather than diffuse. The back side of the reflector is an absorbing surface as well. Analysis using the program CATT-acoustics have shown that the speech hall has a reverberation time of 0,78 seconds and a clarity (C50) of 2,0 dB. The acoustical music hall has a reverberation time of 2,28 seconds and a clarity (C80) of -0,8 dB, these results are desirable. The distribution of sound is less equal than can be seen in a rectangular hall. Because the panels behind the stage can be flipped to reflect or to absorb sound, a large variety of reverberation can be created between 0,78 and 2,28 seconds.

Figure 4. CATT-acoustics analysis for the speech hall (upper two diagrams) and the acoustical music hall (lower two diagrams)

Beranek, L. L. (2004). Concert halls and opera houses. Music, acoustics, and architecture (2nd ed.). New York: Springer-Verslag. 2 Nijs, L. (2014). Ruimteakoestiek. Retrieved 29th May, 2014, from 3 Barron, M. (1993). Auditorium acoustics and architectural design (1st Ed.). London: E & FN Spon and imprint of Chapman & Hall. 1


Heat recovery with hybrid ventilation in office buildings

by ir. Reinier Scholten HVAC systems consumes about 52% of the total energy consumption of an office building (Pérez-Lombard et al., 2008). Most office buildings rely on a HVAC system according to the one-size-fits-all method. There is one HVAC unit for the entire building; clothing and behaviour are the only modifications for the occupants (Brager & de Dear, 2000). A decentralized mechanical ventilation system is a good alternative but this system still uses a lot of energy (Pérez-Lombard et al., 2008). A good solution will be a natural ventilation system. One of the advantages of a natural ventilation system is the acceptance range of the occupants. The occupants in a naturally ventilated building will accept lower and higher temperatures than in mechanically and even decentralized mechanically ventilated buildings (De Dear & Brager, 1998). There is also a greater manual influence of the people working in the offices. This can be achieved by using decentralized ventilation system, so every location can adjust its own settings.

In order to answer this research question several sub questions had to be answered. Like the possibilities of the driving forces of a natural ventilation system. Another sub-question was if the designed ventilation system could be used for single sided ventilation as well as cross ventilation. The system will be designed for a typical 70’s office building in Amsterdam.

Driving forces The total pressure difference (ΔPtotal) between the inlet and outlet can be calculated by adding up the pressure difference create by multiple factors, see formula [1].

Research question By combining the advantages of natural and mechanical ventilation a new ventilation system will be designed by answering the following research question; “How can a decentralized mechanical ventilation system be redesigned to make use of natural ventilation principles?”


Figure 1. Building on which the new ventilation system will be applied. A central corridor with offices on both sides. The offices have a standard size of 3.6 x 6 m.

Reinier Scholten (24) started studying at the TU Delft in 2008. After one year of Civil Engineering he switched to the study of Architecture. During his study he became interested in the technical aspects of architecture. This started with construction and later on his study changed towards integrating passive sustainable solutions in the design in order to save energy. For his master thesis he graduated at January 2015 on the topic of “Heat recovery with hybrid ventilation in office buildings.” under guidance of dr. ir. P. van den Engel and dr. ir. T. Klein. During this research he developed a system which is able to apply heat recovery to a natural ventilation system.

There will be no difference in atmospheric pressure (ΔPath) and the pressure coefficient (ΔPCp) as it is at the same location at about the same height of the building. There will be a pressure

difference as a result of the temperature difference (ΔPtemp) between the floor and the ceiling, and due to both being almost constant throughout the day this will be a constant pressure difference of 0.4 Pa. This leaves the pressure difference created by the wind. The velocity of the wind will result in a pressure difference (ΔPin/ ) due to the shape of the inlet and the outlet of the ventilation out system. The wind speed at the façade will be a result of the vortex pattern in the recirculation zone (Bottema, 1993) and the wind speed at the facade will be 40 % of the main wind velocity (Stathopoulos & Baskaran, 1996). In combination with the characteristic values, correction factors, for the inlet and the outlet (de Gids & den Ouden, 1986) the pressure difference create by the inlet and outlet will be 6.29 Pa.

box’ and a building. The box for the environment will be used to create the three-dimensional mesh and to create the planes for the inlet and outlet of the air. It represents a sort of wind tunnel for the building. For the collected data 5 lines were placed perpendicular to the façade with a length of 1 m at heights of 5, 10, 15, 20 and 25 m. When looking at the data simulated by the Ansys models, it can be noticed that the wind speeds at the leeward side of the building do not create high enough dynamic pressures to overcome the pressure created by the heat exchanger. With an

Formula 1. Total pressure difference.

Wind around the building simulation For the calculation in Ansys a three dimensional model is created. This model is made from the combination of an ‘environment

Figure 2. Measurement lines at heights of 5, 10, 15, 20 and 25 m.


Figure 3. Wind speed results of different heights at the windward side of the building. The x-value represents the distance perpendicular to the facade. Left wind at 0 degrees, right at 30 degrees.

used per office. Each one creating and preheating an air flow of 50 m3/h. In this design the inlet grid will be at a height of 1m and the exhaust vent will be located just below the ceiling. The inlet at the façade consists of a rotating wind cowl. This cowl will always have the opening directed into the wind by using the metal fin mounted at the back. So at every possible angle the inlet will be turned into the wind. The outlet is a stationary system and is used for created a negative pressure at the outlet of the ventilation system. This element acts as a small 3D venturi element. Due to the shape it will create a negative pressure at any given wind direction at the façade. For the heat recovery a Fiwihex heat exchanger was used due to the high efficiency, 85%, at low temperature differences (Vision4Energy, 2014). The wind will not always be sufficient to create a large enough airflow to ventilate the office. If this occurs, a mechanical backup system is needed. This system consists of 2 small fans integrated in the supply and exhaust of the system. These will generate the airflow if the natural principles will not work sufficient.

Simulation Figure 4. Wind speed results of different heights at the leeward side of the building. The x-value represents the distance perpendicular to the facade. Left wind at 0 degrees, right at 30 degrees.

optimal inlet and outlet cowl the pressures can be doubled and will result in values lower than the 4 Pa pressure loss of the heat exchanger at 100 m3/h. As a result of this it can be stated that complete natural ventilation by openings at the façade at the leeward side of the building cannot be created due to the low wind speeds. In this case a mechanical fan will be needed in order to create the needed airflow for ventilation.

Design The ventilations system consists of a thin ‘box’ system which can be mounted next to the window on the inside of the façade. Due the manual control possibilities there will be two systems


This design was also simulated in Ansys Fluent. This simulation setup includes a box for the office , a porous zone for the heat exchanger and a tunnel for creating the wind. Inside the tunnel both façade elements, inlet and outlet, are modelled. The wind velocity in the tunnel was set to the average wind velocity at the façade of 2.4 m/s. This resulted in an air velocity of 1.5 m/s in the system. In combination with the diameter of 0.11 m of the tube will result in a total air flow of 50 m3/h. The pressure drop over the heat exchanger was a lot lower than expected. According to figure x the pressure drop was about 0.2 Pa.

Test setup The test setup will be used for comparing the simulated data with the model. For the test a wind tunnel simulation was created at a scale of 1:1. The total model will exist of a wind tunnel in which the inlet and outlet will be situated. Underneath the wind tunnel the heat exchanger will be placed together with

Rotating inlet cowl

Heat exchanger

Venturi outlet

Figure 5. Principle of the ventilation system (left) and the three main elements of the ventilation system (bottom).


as naturally ventilated buildings accept respectively lower and higher temperatures. For natural ventilation different principles like cross- or singlesided ventilation can be used. Also the driving forces, wind and buoyancy, can be used in different ways with each having their own advantages. A hybrid ventilation system can make use of one of these principles with a mechanical backup system if the created air flow wouldn’t be sufficient. This will also allow the users to adjust the system more easily and making it a perfect solution for reducing the energy consumption of an office building.

Figure 6. Simulation of the design in Ansys Fluent.

an ‘office’. To limit the complexity of the system the inlet and outlet were place on the same side of the heat exchanger and the ‘office’ box was replaced by a U-bend. The wind inside the tunnel was set to two speeds 0.71m/s and 2.4 m/s. This resulted in an average wind velocity inside the system of respectivly 0.24 m/s and 0.87 m/s A simulation was done in order to compare the measured results with the simulated data. In the Ansys-simulation, the air velocities in the ducts of the system were averaged at 0.28 m/s and 1.07 m/s with a peak in the center of 0.31 and 1.29 m/s. This corresponds with the data measured during the test. There is a 20% difference between the simulated and measured data. One possible explanation could be the quality of the setup. Due to the use of simple PVC pipe elements and wooden boxes, there could be more air resistance in the system itself.

Conclusion Natural ventilation is a good alternative for mechanical ventilation. As the current used mechanical ventilation systems use 11% of the total energy usage of a building, a large progress could be made. The stated design would reduce this with 5 %. This is only on ventilation energy. Next to the savings on the ventilation, a lot of energy can be saved on heating and cooling 52

Figure 7. Test setup with the corresponding measuring points

Bibliography Bottema, M. (1993). Wind climate and urban geometry. (PhD), Technische universiteit Eindhoven, Eindhoven. Brager, G., & de Dear, R. (2000). A standard for natural ventilation. ASHRAE journal. De Dear, R., & Brager, G. S. (1998). Developing an adaptive model of thermal comfort and preference. Center for the Built Environment, ASHRAE, 104(1), 145-167. de Gids, W., & den Ouden, H. P. L. (1986). Drie onderzoeken naar de werking van kanalen voor natuurlijke venilatie waarbij nagegaan is de invloed van plaats en hoogte van de uitmonding,van de bebouwing in de omgeving en van de vorm van de uitmonding. Delft: TNO. PĂŠrez-Lombard, L., Ortiz, J., & Pout, C. (2008). A review on buildings energy consumption information. Energy and buildings, 40(3), 394-398. Stathopoulos, T., & Baskaran, B. A. (1996). Computer simulation of wind environmental conditions around buildings. Engineering Structures, 18(11), 876-885. Vision4Energy. (2011). Specification Fiwihex ALPHA 24. Oldenzaal.

Figure 8. Interior (top) and exterior (bottom) view of the ventilation system integrated in the facade element.


Sustainable indoor climate with BaOpt

by Ronald Houtsma

It is difficult to design the ideal indoor climate for people in buildings. With current techniques and insights, 10% of the people remain unsatisfied by the indoor climate system. The indoor climate can be drastic improved by using a groundbreaking climate system. BaOpt reduces climate complaints and saves energy. Air currents play an important role in all indoor climate design choices made by installers and consultants. The air currents are used to direct fresh, warm or cold air to the living zone of people. A maximum air speed of 0.15 m/s in the occupied zone is permitted. Often the air current is the cause of many climate complaints. Temperature stratification, cold air near facades, air vents of the ventilation system, air swirls caused by obstacles and the heat of devices have an adverse effect on air velocity and therefor also on climate comfort.

Improving with traditional methods How can the indoor climate be improved using traditional methods? To achieve this the climate system is often extended with individual room climate controls. The desired room temperature can be set on these devices. This makes people feel that they have influence on the climate. However, the underlying problem is only partially solved. The unmodified air movement remains a risk to climate problems.


Climate system from Germany In Germany a solution in relation to the disadvantage of the air flow was developed. The climate system is developed by Albert Bauer. In the Netherlands, the system has been available for several years as Bauer Optimierungstechnik, short BaOpt. There is no temperature stratification in a BaOpt situation, and identical conditions are measured in the room at any spot. Result: draft along the cold facades no longer has any influence on the living area.

The BaOpt effect Figures 1 and 2 show that with the conventional air conditioning system a lot of air swirls occur, but that this is not the case with the BaOpt climate installation. On the inside of the facade a stagnant layer of air is created (contact resistance Ri). In traditional air conditioning systems this layer is disturbed by convection, with BaOpt this disturbance does not occur. The result is an insulating layer of air on the inside of the facade. This results in approximately 30% less heat loss. Also, there will be no cold air flows along the facade. The BaOpt effect can be explained by the following examples.

Ronald Houtsma is a consultant at Antea Group, Department of Construction & Energy, and since 1994 working in the installation business. At Deltion College in Zwolle and TVVL Leusden he followed the profession-oriented courses. At Fontys Groningen he obtained the PDD (Pedagogical Teaching Diploma). He also had management training for young engineers at University of Twente.

Currents in aquarium We take an empty aquarium and suggest that this is an empty office. The tank is filled with water from above. The water splashes into the aquarium as if the office is filled with fresh air, as it would occur in a conventional ventilation system. After a period of time, the water is drained and replenished, because ultimately the oxygen has disappeared from the water. During the filling and discharge of water in the aquarium, flows and swirls occur that are not fully controllable. These flows and swirls also occur in the room air and are not visible, but are sensible.

Atomising in an aquarium The tank is again filled with water and we let the water settle. In order to visualize the BaOpt effect, ink is now added dropwise to the water. The drops of ink symbolize the fresh air, entering an office. We see the inkdrops fall apart and distribute in the water, while this is happening no currents or swirls start to occur in the water. This shows that there are no uncontrolled air movements in the office. Also, it can be seen that there is no temperature stratification in the office space. The resulting mix of ink and water is reasonably quick homogeneous. Then we gradually drain this mixture from the office and start adding water and ink simultaneously again. With this example we made visible, that indeed the air is refreshed in the homogeneous conditions.

Figure 1. Traditional climate installation. The traditional HVAC systems operate on the basis of airflow. The indoor air quality, including the room air temperature and the CO2 content of the room air, are conditioned by airflow. A disadvantage of airflow is that it is perceived by people as drafts.

Figure 2. BaOpt Climate Installation. In a BaOpt climate no air movement is experienced. Thermoregulation of the body is not disturbed by BaOpt, so the climate is experienced as pleasant. Because of a small overpressure in the area the room air is refreshed.


Heerenduinen Swimming pool The previous example is an illustration, but can we experience homogeneous conditions of the indoor climate in practice? At Heerenduinen swimming pool in IJmuiden (figure 3) we find out. The climate in a pool is difficult to manage because of the many influences. Due to the high humidity, moisture may condensate on the windows and on the steel structures. This can have serious consequences for the pool. A quote of the facility manager of the swimming pool: “the climate in the pool was previously not pleasant for the teaching staff and the smell of chlorine dominated the pool areas with climate complaints as a result”.

No air turbulence, less evaporation swimming water Figure 3. Swimming pool Heerenduinen in IJmuiden

Because there is no air turbulence in a BaOpt regulated area, the layer of air on the surface of the bathing water is not disturbed. Because of this there is less evaporation of bathing water. This has a positive effect on the climate conditions. Have you ever experienced a chill, when you come out of the pool? This will not happen in a BaOpt situation, because the stagnant air will not cool your body. The facility manager of Heerenduinen shows the building management system, which shows that space temperatures in the swimminghall hardly differ (figure 4). And power consumption is also dramatically reduced. The visit to Heerenduinen swimming pool gives a good impression of how the BaOpt climate is experienced.

Basic requirements climate systems The BaOpt climate system places certain requirements on the basic installation. BaOpt allows heat and cold transfer through the air. Ventilation must occur through an air handling-unit with frequency arrangements. The control system must be equipped with a building management system with remote handling Radiator heating in a BaOpt situation is redundant and can be removed. Heat or cold through convection should not occur in a BaOpt situation, because it is based on airflow. Radiant heat 56

is possible with BaOpt because radiation will heat the room air (think of solar radiation). A homogeneous climate condition is achieved by creating an excess pressure of 4 Pascal in the building with respect to outside air. This slightly higher atmospheric pressure is hardly perceived by people.

Case: climate solution complaints MFC A government agency presented us with a question about a multifunctional centre (MFC) where climate complaints occur. The building serves as a multipurpose building with a gross floor area of 3,700 m2. The climate complaints are: it’s too hot and stuffy in the rooms, there are hardly windows that can be opened, dry air, a cold draught from the windows in winter and during the summer time the window frames are hot. Research has shown that the building shell has thermal bridges. The climate system consists of concrete core activation, a heat pump system and two air handling units with mechanical balanced ventilation. The air ducts includes channel reheaters. In some areas the temperature post-controls have been placed.

Figure 4. Room temperature swimming hall ““What’s so special about BaOpt, is that a stagnant air layer forms on the walls, windows and frames of the area. This stagnant air layer works as an extra insulator on the constructional shell. There will be no condensation. The Rsi (internal interior surface resistance) is much greater than 0.13 m2K / W.

The work No major work is carried out in the classrooms and other living/ working areas. The current channel system with ventilation can be maintained. The work will take place mainly in the technical areas, the air handling units and in the corridor zones (figures 4,5 and 6).

Figure 4. BaOpt conditions. The climatic condition of each space has been made visible in the control of BaOpt. If the classroom is put into operation, it is apparent that the CO2 content increases. The permissible CO2 content for the classroom is approximately 1,200 PPM. In order to ensure the optimal learning performance, the required limit value is set to 800 PPM. The graph shows that the BaOpt system continuously monitors and if necessary improves the air conditions.

Conclusion The system BaOpt is a good addition to the design choices for sustainable climate systems while simultaneously improving climate conditions. The investment for the BaOpt system can pay for itself, in most cases within five years. The BaOpt system is applicable to various buildings, such as swimming pools, theatres, schools, offices, museums, cinemas and multifunctional centres. For existing buildings BaOpt reduces climate complaints strongly and also achieves energy savings. For new buildings, it means that with BaOpt optimal comfort can be created that meets the Trias Energetica.

Figure 5. BaOpt room temperature. The room temperature is an important indicator of comfort in the room. The graph shows that when the classroom is put into operation, the desired room temperature of 20 degrees can be well controlled by the BaOpt system.


Sensors and control valves, for air inlet and outlet, will be placed in each zone. Within a zone, air ducts will not be necessarily. Each zone will be adapted individually to the current use and the desired conditions.

Figure 6. BaOpt zone control system. It is possible to integrate the BaOpt climate control in the current climate installation of the MFC. BaOpt climate is suitable to be combined with concrete core activation. The current air handling units are equipped with frequency switches. In both return vent and supply vent a pressure switch is added. These are connected to the BaOpt controls. The ventilation system of the building is divided into zones or control areas.


’ es


am ‘W t en comforta n a g e be el l


Het uitgangspunt bij het ontwerpen van deze stoel was het maken van een luie ligstoel die zo transparant mogelijk oogt en die, als de stoel niet wordt gebruikt, nauwelijks volume heeft. De details zijn eenvoudig gehouden. Als basismateriaal voor de stoel is gekozen voor verenstaal vanwege het flexibele gedrag bij belasting. De zitting is van canvasdoek bekleed met leer of textiel en de losse rugelementen worden via kabels aan het frame bevestigd, waardoor de stoel zeer flexibel en dus comfortabel is.

Jan Brouwer +31 6 51 31 62 50 Chris Karthaus +31 6 46 32 70 21

Cabinet 02.West.090 Faculty of Architecture Julianalaan 134 2628BL Delft The Netherlands PRAKTIJKVERENIGING


student association for building technology

+31 (0)15 278 1292

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