An overview is given of the state-of-the-art of natural and hybrid ventilation in buildings in general. The focus of this paper is on boundary conditions for openable windows. As a case study the Co Creation Centre at the TU-Delft is discussed. Occupants live in their own houses and often in an office or other working environments as well. Due to the development of working on a distance, accelerated by the COVID-pandemics, they generally have more choice which environment is the best. That is why a holistic approach is necessary for buildings in general and houses. Natural ventilation offers a wide range of low-cost opportunities to realize the required thermal comfort and need of fresh air. Boundary conditions for ventilation are the limitation of cooling and heating by intelligent building physical design of the façade or roof, with better balancing heat loss due to transmission and heat gain by solar access. In this field there is still a lack of knowledge at many professionals. In most cases natural ventilation has to be supported by robust mechanical systems. Effective integration is a rather new field of research, learning from the past. Current examples of integration are discussed, in which BMS-systems play a key role.@en

This research evaluates the performance of a Phase Change Material (PCM) battery integrated into the climate system of a new transparent meeting center. The main research questions are: a. “Can the performance of the battery be calculated?” and b. “Can the battery reduce the heating and cooling energy demand in a significant way?” The first question is answered in this document. In order to be able to answer the second question, especially the way the heat loading in winter should be improved, then more research is necessary. In addition to the thermal battery, which consists of Phase Change Material plates, the climate system has a cross-flow heat exchanger and a heat pump. The battery should play a central role in closing the thermal balance of the lightweight building, which can be loaded with hot return or cold outdoor air. The temperature of the battery plates is monitored by multi-sensors and simulated by the use of PHOENICS (Computational Fluid Dynamics) and MATLAB. This paper reports reasonable agreement between the numerical predictions and the measurements, with a maximum variance of 10%. The current coefficient of performance for heating and cooling is already high, more than 27. There is scope for increasing this much further by making use of the very low-pressure difference of the battery (below 25 Pascal), low pressure fans and the ventilation system as a whole.

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Satisfying thermal comfort in indoor spaces is still a challenge in terms of energy saving, and several HVAC (Heating, Ventilation, and Air-Conditioning) systems have been proposed for this purpose. This paper conducts an analysis to evaluate and optimize the long-term operation of a novel HVAC system installed at The Green Village, a living lab in Delft, the Netherlands. This system comprises all-glass facades with steerable solar shades, sky windows, a climate tower equipped with Phase-Change Material (PCM), a heat recovery unit, and a heat pump. The current analysis draws on transient modeling to predict the system's behavior while relying on constrained nonlinear optimization to select the optimal design parameters (e.g. floor heat capacity and solar absorptance) and optimal operational conditions (e.g. use of PCM and heat recovery unit, aperture of sky windows and solar shadings). The goal is to schedule the control inputs to operate the system as much as possible as a passive energy system, with minimal active power all year round. The results show that the optimization can reduce the yearly heat demand by around 10.6%, with the solar shadings being the most significant component to be optimized. Furthermore, the optimized system is capable to supply 58% of the annual thermal demand passively – In this case, an auxiliary thermal demand of only 27 kWh/m²/year is required, which may qualify the system as a low-energy building.

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The book was first issued in 2019. June 2023 a new version of this book is placed on the site.

More attention is payed to:
- Covid and ventilation (new)
- Openable windows and grids, how and when to use?
- Energy use of ventilation systems
- Elementary calculation software

The aim of the book is to give an overview of the advantages, history and principles of hybrid and mixed mode ventilation. Natural ventilation plays a key role to improve comfort and reducing energy. In order to make natural ventilation successful, an early integration in the design-process is necessary. In the long term fully natural ventilated buildings are expected to become the standard, even in high rise buildings (Wood 2013). However, much more scientific development is necessary in order to guarantee that these buildings will behave as expected. The book is not an advertising book for natural ventilation. In many cases natural ventilation alone for climate control is not possible. However, in most of the cases hybrid or mixed mode types can be applied and these options need more attention. Adaptive thermal comfort is closely related to hybrid and mixed mode buildings in which a wide range of temperatures are possible, with substantial options of saving energy (Humphreys 2015). Designing natural, hybrid or mixed mode buildings requires a complete other way of thinking about design. It is partly a mixture of mechanical, building physical and architectural engineering, but it is also more. Knowledge about natural air flows and designing with natural air flows is in fact a new profession, for which this book gives a general, and sometimes detailed, outline.@en

This research gives an overview of the current comfort and energy performance, and optional future design of highly transparent and lightweight buildings. The transparent Co-Creation Centre in the Green Village at the TU Delft, has a combination of active and passive climate control measures. The aim of the research is to show how transparent buildings with a high glass/floor percentage (here 122 %) perform and how these could be optimized. An overview of the research project and system integration is presented, with the focus on energy, comfort and working of the BMS-system. Energy and comfort performances are measured and simulated. Validation has been executed of daylight, solar heat access, and thermal performances. A large Phase Change Material (PCM) buffer in the air handling unit reduces the heating and cooling demand. Making use of passive qualities of the outdoor and indoor air temperature and solar energy requires a more complex control strategy than usual. A Model Predictive Control (MPC) strategy has been investigated and can optimize the energy consumption.@en

This interactive, 90 minute workshop was proposed to encourage designers to take stock of innovative ventilation solutions being built today and then consider what might be effective design solutions for buildings in 28 years’ time, in 2050. The aim was to explore how shared learning might influence how we think about designing resilient buildings today for a different future. Attendees were handed a two sided questionnaire at the start of the session on one side of which were questions to be answered at the start of the workshop and on the reverse, questions for the end of the workshop to try and understand how much thinking had changed over the 90 minutes. Peter then gave his talk on Innovative Passive Solutions and the attendees got into groups and discussed how they would answer the first set of questions. The agreed answers were put up on sticky notes on the wall under the titles: Resilient building features; 2050 technologies and Human factors. Sue then gave her talk on Designing for 2050. She used the case study of the Oxford Ecohouse she built 28 years ago as an example of a building that would still perform well in the much hotter climate predicted for 2050. 28 years in the future. After her talk, and during the round-up discussions people were asked to note down any changes in thinking under those three titles to try and get a feel for how much the workshop has affected their ideas on these issues. Peter then collected the questionnaires and sticky notes and recorded the results that are presented below. @en

Vroeger werden gebouwen natuurlijk geventileerd en daglicht was de voornaamste bron van verlichting. Het binnenklimaat was vooral afhankelijk van het type gevel, dak, thermische massa en lokale verwarming. Overal in de wereld kunnen voorbeelden van traditionele gebouwen worden gevonden met een binnenklimaat waarin mensen zich comfortabel voelen door zichzelf en de omgeving aan te passen om comfort te bereiken. In zekere zin zouden dit prototypes kunnen zijn van moderne gebouwen. Aan de andere kant zijn de eisen voor architectonische expressie, gebruik, comfort en energie nu anders, wat om een nieuwe benadering vraagt. De isolatie van gebouwen, van de dichte en transparante delen, is zodanig verbeterd dat nauwelijks meer ruimteverwarming nodig is. Voorkomen van onnodige koeling vraagt nu de meeste aandacht. Het vinden van de juiste hoeveelheid daglicht en zonlicht, in elk seizoen en bij verschillend weer, zou een belangrijk ontwerpdoel moeten zijn. Natuurlijke en lage druk ventilatie biedt daarnaast veel mogelijkheden om plaatselijk comfort te verbeteren en ventilator- en koelenergie te verminderen. Er is een sterke relatie met het ontwerp van de gevel en de architectonische expressie. Verschillende voorbeelden van over de hele wereld worden besproken.@en

For several years indoor comfort is measured in halls of hospitals by architecture students from the Delft University of Technology. Questionnaires and interviews have shows that patients and visitors have very few complaints about the indoor comfort in hospital halls. This, in hindsight, is not so very surprising. Patients and visitors usually come out of the cold into the hallway. A hallway which is at least marginally warmer, a hallway where it does not rain and hallway that is sheltered from the outside wind. Secondly, the indoor comfort is not the main concern of the patients and visitors entering the hospital. The patient’s and visitor’s upcoming consults with the doctors or nurses is much more important. Coming from the consult, patients and visitors always have the choice to immediately leave the hospital if they do not like the indoor comfort. Complaints from staff, however, are very common. Staff personnel usually complain about low temperatures and draught. A reception desk is the main workplace in a hospital hall. A reception desk can be closed, i.e. physically separates the personnel from the environment of the hall. A reception desk can also be open, thus without a physical separation between personnel and patients and visitors. In a hospital, in general, an open reception desk is favoured for a more welcoming atmosphere for patients and visitors. This more open reception desk, however, often causes the personnel to experience low temperatures and draught. From this study it is clear that it is very difficult design a thermally comfortable reception desk in a hospital. The quest for a reception that expresses openness and transparency clearly hinders the design for a comfortable reception desk. On the other hand, the small number of people at the reception desk is in no comparison to the hundreds of staff and patients for which the hospital is also designed. Many solutions to improve thermal comfort at a reception desk are already known. The exact cause of the experienced draught and the best solutions, however, are difficult to determine. Scale models or CFD simulations should be used as a guide for design a reception desk in a hospital or when solving thermal comfort problems. A new cause of draught, people moving past the reception desk, was identified and quantified. As a result, a completely open reception desk inside a large atrium with a lot of people moving past might not be possible without either closing off the reception desk, or increasing the temperature at the reception desk.@en

The handbook gives an overview of natural ventilation principles of buildings, often integrated in mechanical systems, and integration with daylight design.@en

Overview of the options of high inducing natural air supply and discussion about the theory of draught.@en

An overview is given of recent developments in the use of a system of inducing natural air supply via the façade in the Netherlands. This is followed by a review of the results of measurements from climate chamber experiments of its inducing ventilation performance and detailed insights gained from related experiments of climate chamber measurements for a school and a hospital. Finally, lessons learned from practical experience gained in a newly built office and two schools are outlined. These studies of different systems of natural air supply via the facade are used to inform a scoping review of options for use in the design of new buildings using such systems in the future. Because turbulence is an important comfort-parameter, having a positive as well as negative influence on comfort and with physical principles that are, in relation to a number of parameters, still unknown, the issue of turbulence within such systems is discussed in more detail.@en

Greenhouses in The Netherlands contribute significantly to the total energy consumption of the country. One of the leading Dutch philosophies for greenhouses is “the new growing” which reduce energy and improve health, quality and growing of plants: a greenhouse with an adaptive kind of comfort with a free running climate. Heating is necessary to prevent cold stress of plants or condensation. The relative humidity should be just low enough to prevent heat stress of plants or development of fungus. Ground ducts can reduce heating and cooling of air, reverse stratification, improve circulation and dehumidification. These ducts are heated up during the day by the air from the top of the green house, above the screens. In the thermal buffer of the ground solar heat is accumulated and released in the cold early morning. After measurements in a greenhouse with ground ducts, a calculation-model in Matlab is developed and validated. The diurnal temperature-swing in a ground duct is evaluated with the mathematic model of Hollmüller. Via the Matlab-model the energy savings and the effect of the amount and size of ground ducts can be predicted. The system has proved to create better developed tomatoes with almost no diseases anymore.@en

The thermal comfort level distribution in high-rise residential buildings is seldomly checked in the Netherlands. At building scale, height and orientation were found to be the crucial parameters in the thermal comfort distribution in a regular high-rise residential building. At room scale, privacy and safety were found to be closely related to the use of the natural ventilation system. Based on the findings, different strategies are proposed to improve thermal comfort, concentrating on the summer period.@en