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Personal lighting conditions of office workers: An exploratory field study

Light enables us to see and perceive our environment but it also initiates effects beyond vision, such as alertness. Literature describes that at least six factors are relevant for initiating effects beyond vision. The exact relationship between these factors and alertness is not yet fully understood. In the current field study, personal lighting conditions of 62 Dutch office workers (aged 49.7 ± 11.4 years) were continuously measured and simultaneously self-reported activities and locations during the day were gathered via diaries. Each office worker participated 10 working days in spring 2017. Personal lighting conditions were interpreted based on four of the six factors (light quantity, spectrum, timing, and duration of light exposure). Large individual differences were found for the daily luminous exposures, illuminances, correlated colour temperatures, and irradiances measured with the blue sensor area of the dosimeter. The average illuminance (over all participants and all days) over the course of the day peaked three times. The analysis of the duration of light exposure demonstrated that the participants were on average only exposed to an illuminance above 1000 lx for 72 minutes per day. The interpretation of personal lighting conditions based on the four factors provides essential information since all of these factors may be relevant for initiating effects beyond vision. The findings in the current paper give first in-depth insight in the possibilities to interpret personal lighting conditions of office workers.

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Personal lighting conditions of office workers: An exploratory field study

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The future of lighting design beyond lighting design.

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Exploring the relationship between light and subjective alertness using personal lighting conditions

Journal of Physics: Conference Series Paper • The following article is Open access Exploring the relationship between light and subjective alertness using personal lighting conditions J. van Duijnhoven1, M.P.J. Aarts1, E.R. van den Heuvel2 and H.S.M. Kort3,4 Published under licence by IOP Publishing Ltd Journal of Physics: Conference Series, Volume 2042, CISBAT 2021 Carbon-neutral cities - energy efficiency and renewables in the digital era 8-10 September 2021, EPFL Lausanne, Switzerland Citation J. van Duijnhoven et al 2021 J. Phys.: Conf. Ser. 2042 012119 Download Article PDF References Download PDF 29 Total downloads Turn on MathJax Share this article Share this content via email Share on Facebook (opens new window) Share on Twitter (opens new window) Share on Mendeley (opens new window) Hide article information Author e-mails j.v.duijnhoven1@tue.nl Author affiliations 1 Building Lighting Group, Department of the Built Environment, Eindhoven University of Technology, Eindhoven, The Netherlands 2 Stochastics, Department of Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands 3 Research Centre Healthy and Sustainable Living, University of Applied Sciences Utrecht, Utrecht, The Netherlands 4 Building Healthy Environments for Future Users Group, Department of the Built Environment, Eindhoven University of Technology, Eindhoven, The Netherlands DOI https://doi.org/10.1088/1742-6596/2042/1/012119 Buy this article in print Journal RSS Sign up for new issue notifications Create citation alert Abstract The discovery of the ipRGCs was thought to fully explain the mechanism behind the relationship between light and effects beyond vision such as alertness. However, this relationship turned out to be more complicated. The current paper describes, by using personal lighting conditions in a field study, further exploration of the relationship between light and subjective alertness during daytime. Findings show that this relationship is highly dependent on the individual. Although nearly all dose-response curves between personal lighting conditions and subjective alertness determined in this study turned out to be not significant, the results may be of high importance in the exploration of the exact relationship.

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Exploring the relationship between light and subjective alertness using personal lighting conditions

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Marco Bevolo

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Projecten 7

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Design and Development of Wobbling Triboelectric Nanogenerators for Energy Harvesting

TU Delft, in collaboration with Gravity Energy BV, has conducted a feasibility study on harvesting electric energy from wind and vibrations using a wobbling triboelectric nanogenerator (WTENG). Unlike conventional wind turbines, the WTENG converts wind/vibration energy into contact-separation events through a wobbling structure and unbalanced mass. Initial experimental findings demonstrated a peak power density of 1.6 W/m² under optimal conditions. Additionally, the harvester successfully charged a 3.7V lithium-ion battery with over 4.5 μA, illustrated in a self-powered light mast as a practical demonstration in collaboration with TimberLAB. This project aims to advance this research by developing a functioning prototype for public spaces, particularly lanterns, in partnership with TimberLAB and Gravity Energy. The study will explore the potential of triboelectric nanogenerators (TENG) and piezoelectric materials to optimize energy harvesting efficiency and power output. Specifically, the project will focus on improving the WTENG's output power for practical applications by optimizing parameters such as electrode dimensions and contact-separation quality. It will also explore cost-effective, commercially available materials and best fabrication/assembly strategies to simplify scalability for different length scales and power outputs. The research will proceed with the following steps: Design and Prototype Development: Create a prototype WTENG to evaluate energy harvesting efficiency and the quantity of energy harvested. A hybrid of TENG and piezoelectric materials will be designed and assessed. Optimization: Refine the system's design by considering the scaling effect and combinations of TENG-piezoelectric materials, focusing on maximizing energy efficiency (power output). This includes exploring size effects and optimal dimensions. Real-World Application Demonstration: Assess the optimized system's potential to power lanterns in close collaboration with TimberLAB, DVC Groep BV and Gravity Energy. Identify key parameters affecting the efficiency of WTENG technology and propose a roadmap for its exploitation in other applications such as public space lighting and charging.

In voorbereiding

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Designing solar steering light for sustainable horticulture

Horticulture crops and plants use only a limited part of the solar spectrum for their growth, the photosynthetically active radiation (PAR); even within PAR, different spectral regions have different functionality for plant growth, and so different light spectra are used to influence different properties of the plant, such as leaves, fruiting, longer stems and other plant properties. Artificial lighting, typically with LEDs, has been used to provide these specified spectra per plant, defined by their light recipe. This light is called steering light. While the natural sunlight provides a much more sustainable and abundant form of energy, however, the solar spectrum is not tuned towards specific plant needs. In this project, we capitalize on recent breakthroughs in nanoscience to optimally shape the solar spectrum, and produce a spectrally selective steering light, i.e. convert the energy of the entire solar spectrum into a spectrum most useful for agriculture and plant growth to utilize the sustainable solar energy to its fullest, and save on artificial lighting and electricity. We will take advantage of the developed light recipes and create a sustainable alternative to LED steering light, using nanomaterials to optimally shape the natural sunlight spectrum, while maintaining the increased yields. As a proof of concept, we are targeting the compactness of ornamental plants and seek to steer the plants’ growth to reduce leaf extension and thus be more valuable. To realize this project the Peter Schall group at the UvA leads this effort together with the university spinout, SolarFoil, whose expertise lies in the development of spectral conversion layers for horticulture. Renolit - a plastic manufacturer and Chemtrix, expert in flow synthesis, provide expertise and technical support to scale the foil, while Ludvig-Svensson, a pioneer in greenhouse climate screens, provides the desired light specifications and tests the foil in a controlled setting.

Afgerond

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MAESTRO-drone

In 2024, the Dutch government set a new plan for offshore wind farms to become the Netherlands' largest power source by 2032, aiming for 21 GW of installed capacity. By 2050, they expect between 38 and 72 GW of offshore wind power to meet climate-neutral energy goals. Achieving this depends heavily on efficient wind turbines (WTs) operation, but WTs face issues like cavitation, bird strikes, and corrosion, all of which reduce energy output. Regular Inspection and Maintenance (I&M) of WTs is crucial but remains underdeveloped in current wind farms. Presently, I&M tasks are done by on-site workers using rope access, which is time-consuming, costly, and dangerous. Moreover, weather conditions and personnel availability further hinder the efficiency of these operations. The number of operational WTs is expected to rise in the coming years, while the availability of service personnel will keep on declining, highlighting the need for safer and more cost-effective solutions. One promising innovation is the use of aerial robots, or drones, for I&M tasks. Recent developments show that they can perform tasks requiring physical interaction with the environment, such as WT inspections and maintenance. However, the current design of drones is often task-specific, making it financially unfeasible for small and medium-sized enterprises (SMEs) – providing services in WT inspection and maintenance- to adopt. Together with knowledge institutes, SMEs and innovation clusters, this project addresses these urgent challenges by exploring the question of how to develop a modular aerial robot that can be easily and intuitively deployed in offshore environments for inspecting and maintaining WTs to facilitate SMEs adoption of this technology? The goal is to create a modular drone that can be equipped with various tools for different tasks, reducing financial burdens for SMEs, improving worker safety, and facilitating efficient green energy production to support the renewable energy transition.

Lopend

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Ph.D.-project 'Examining in-class activities to facilitate academic achievement in higher education: a framework for optimal indoor environmental conditions'

Examining in-class activities to facilitate academic achievement in higher educationThere is an increasing interest in how to create an effective and comfortable indoor environment for lecturers and students in higher education. To achieve evidence-based improvements in the indoor environmental quality (IEQ) of higher education learning environments, this research aimed to gain new knowledge for creating optimal indoor environmental conditions that best facilitate in-class activities, i.e. teaching and learning, and foster academic achievement. The academic performance of lecturers and students is subdivided into short-term academic performance, for example, during a lecture and long-term academic performance, during an academic course or year, for example. First, a systematic literature review was conducted to reveal the effect of indoor environmental quality in classrooms in higher education on the quality of teaching, the quality of learning, and students’ academic achievement. With the information gathered on the applied methods during the literature review, a systematic approach was developed and validated to capture the effect of the IEQ on the main outcomes. This approach enables research that aims to examine the effect of all four IEQ parameters, indoor air quality, thermal conditions, lighting conditions, and acoustic conditions on students’ perceptions, responses, and short-term academic performance in the context of higher education classrooms. Next, a field experiment was conducted, applying the validated systematic approach, to explore the effect of multiple indoor environmental parameters on students and their short-term academic performance in higher education. Finally, a qualitative case study gathered lecturers’ and students’ perceptions related to the IEQ. Furthermore, how these users interact with the environment to maintain an acceptable IEQ was studied.During the systematic literature review, multiple scientific databases were searched to identify relevant scientific evidence. After the screening process, 21 publications were included. The collected evidence showed that IEQ can contribute positively to students’ academic achievement. However, it can also affect the performance of students negatively, even if the IEQ meets current standards for classrooms’ IEQ conditions. Not one optimal IEQ was identified after studying the evidence. Indoor environmental conditions in which students perform at their best differ and are task depended, indicating that classrooms should facilitate multiple indoor environmental conditions. Furthermore, the evidence provides practical information for improving the design of experimental studies, helps researchers in identifying relevant parameters, and lists methods to examine the influence of the IEQ on users.The measurement methods deduced from the included studies of the literature review, were used for the development of a systematic approach measuring classroom IEQ and students’ perceived IEQ, internal responses, and short-term academic performance. This approach allowed studying the effect of multiple IEQ parameters simultaneously and was tested in a pilot study during a regular academic course. The perceptions, internal responses, and short-term academic performance of participating students were measured. The results show associations between natural variations of the IEQ and students’ perceptions. These perceptions were associated with their physiological and cognitive responses. Furthermore, students’ perceived cognitive responses were associated with their short-term academic performance. These observed associations confirm the construct validity of the composed systematic approach. This systematic approach was then applied in a field experiment, to explore the effect of multiple indoor environmental parameters on students and their short-term academic performance in higher education. A field study, with a between-groups experimental design, was conducted during a regular academic course in 2020-2021 to analyze the effect of different acoustic, lighting, and indoor air quality (IAQ) conditions. First, the reverberation time was manipulated to 0.4 s in the intervention condition (control condition 0.6 s). Second, the horizontal illuminance level was raised from 500 to 750 lx in the intervention condition (control condition 500 lx). These conditions correspond with quality class A (intervention condition) and B (control condition), specified in Dutch IEQ guidelines for school buildings (2015). Third, the IAQ, which was ~1100 ppm carbon dioxide (CO2), as a proxy for IAQ, was improved to CO2 concentrations under 800 ppm, meeting quality class A in both conditions. Students’ perceptions were measured during seven campaigns with a questionnaire; their actual cognitive and short-term academic performances were evaluated with validated tests and an academic test, composed by the lecturer, as a subject-matter-expert on the taught topic, covered subjects discussed during the lecture. From 201 students 527 responses were collected and analyzed. A reduced RT in combination with raised HI improved students’ perceptions of the lighting environment, internal responses, and quality of learning. However, this experimental condition negatively influenced students’ ability to solve problems, while students' content-related test scores were not influenced. This shows that although quality class A conditions for RT and HI improved students’ perceptions, it did not influence their short-term academic performance. Furthermore, the benefits of reduced RT in combination with raised HI were not observed in improved IAQ conditions. Whether the sequential order of the experimental conditions is relevant in inducing these effects and/or whether improving two parameters is already beneficial, is unknownFinally, a qualitative case study explored lecturers’ and students’ perceptions of the IEQ of classrooms, which are suitable to give tutorials with a maximum capacity of about 30 students. Furthermore, how lecturers and students interact with this indoor environment to maintain an acceptable IEQ was examined. Eleven lecturers of the Hanze University of Applied Sciences (UAS), located in the northern part of the Netherlands, and twenty-four of its students participated in three focus group discussions. The findings show that lecturers and students experience poor thermal, lighting, acoustic, and IAQ conditions which may influence teaching and learning performance. Furthermore, maintaining acceptable thermal and IAQ conditions was difficult for lecturers as opening windows or doors caused noise disturbances. In uncomfortable conditions, lecturers may decide to pause earlier or shorten a lecture. When students experienced discomfort, it may affect their ability to concentrate, their emotional status, and their quality of learning. Acceptable air and thermal conditions in classrooms will mitigate the need to open windows and doors. This allows lecturers to keep doors and windows closed, combining better classroom conditions with neither noise disturbances nor related distractions. Designers and engineers should take these end users’ perceptions into account, often monitored by facility management (FM), during the renovation or construction of university buildings to achieve optimal IEQ conditions in higher education classrooms.The results of these four studies indicate that there is not a one-size fits all indoor environmental quality to facilitate optimal in-class activities. Classrooms’ thermal environment should be effectively controlled with the option of a local (manual) intervention. Classrooms’ lighting conditions should also be adjustable, both in light color and light intensity. This enables lecturers to adjust the indoor environment to facilitate in-class activities optimally. Lecturers must be informed by the building operator, for example, professionals of the Facility Department, how to change classrooms’ IEQ settings. And this may differ per classroom because each building, in which the classroom is located, is operated differently apart from the classroom location in the building, exposure to the environment, and its use. The knowledge that has come available from this study, shows that optimal indoor environmental conditions can positively influence lecturers’ and students’ comfort, health, emotional balance, and performance. These outcomes have the capacity to contribute to an improved school climate and thus academic achievement.

Afgerond

project

Rivierwerken

Er wordt continu ‘reuzenarbeid’ verricht in het rivierengebied in het teken van hoogwaterbescherming, vaarwegbeheer, natuurontwikkeling en delfstoffenwinning. Bij veel van deze rivierprojecten maakt grondverzet het grootste deel uit. Het is onder andere bepalend voor de kosten, de CO2-footprint en de omgevingshinder van dergelijke projecten, en de ruimtelijke kwaliteit van het rivierlandschap. Slim omgaan met grond is daarom een sleutelfactor van duurzaam rivierbeheer. Het onderwerp heeft daarom een prominente plek in verschillende kennis- en innovatieagenda’s, zoals de KIA Landbouw, Voedsel en Water, de KIA Circulaire Economie, en de KIA van het Hoogwaterbeschermingsprogramma. Deze articuleren een behoefte aan praktijkgericht onderzoek dat bijdraagt aan verduurzaming en kostenreductie van grondverzet, zodat grondverzet in 2030 energieneutraal is, de kosten per m3 tussen 2020 en 2030 aanzienlijk gedaald zijn en dat er in 2030 een gezonde slibeconomie is voor circulair materiaalgebruik. Desondanks moet er nog heel wat water door de Rijn voordat bovenstaande ambities in de praktijk kunnen worden gehaald. Het doel van dit project is om praktische inzichten en tools voor duurzaam grondmanagement in riviergebieden te ontwikkelen. Een consortium van 22 partijen (publiek, privaat, kennis) zal onder leiding van HAN lectoraat Sustainable River Management praktijkgericht onderzoek doen ter ondersteuning van technisch managers, ontwerpers, risicomanagers, projectmanagers en beheerders van dijken en uiterwaarden. Door middel van o.a. materiaalonderzoek, ontwerpend onderzoek en evaluaties worden praktische handvatten ontwikkeld voor realisatiestrategieën voor grondstoffenwinning volgens het DNA van de rivier, en het bruikbaar maken van sediment en gebiedseigen grond voor toepassing in de dijkenbouw. Bovendien worden verbeterde werkwijzen en tools ontwikkeld voor het op riviertakniveau afstemmen van vraag en aanbod van delfstoffen in natuur- en dijkversterkingsprojecten in het rivierengebied. Hiermee levert het project een concrete bijdrage aan de invulling van het Grondstoffenakkoord en het Rijksprogramma ‘Nederland Circulair in 2050’.

Afgerond

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TimeTravel: Digital Archives of Amsterdam’s Underground for Circular Building Practices

In summer 2020, part of a quay wall in Amsterdam collapsed, and in 2010, construction for a parking lot in Amsterdam was hindered by old sewage lines. New sustainable electric systems are being built on top of the foundations of old windmills, in places where industry thrived in the 19th century. All these examples have one point in common: They involve largely unknown and invisible historic underground structures in a densely built historic city. We argue that truly circular building practices in old cities require smart interfaces that allow the circular use of data from the past when planning the future. The continuous use and reuse of the same plots of land stands in stark contrast with the discontinuity and dispersed nature of project-oriented information. Construction and data technology improves, but information about the past is incomplete. We have to break through the lack of historic continuity of data to make building practices truly circular. Future-oriented construction in Amsterdam requires historic knowledge and continuous documentation of interventions and findings over time. A web portal will bring together a range of diverse public and private, professional and citizen stakeholders, each with their own interests and needs. Two creative industry stakeholders, Yume interactive (Yume) and publisher NAI010, come together to work with a major engineering office (Witteveen+Bos), the AMS Institute, the office of Engineering of the Municipality of Amsterdam, UNESCO NL and two faculties of Delft University of Technology (Architecture and Computer Science) to inventorize historic datasets on the Amsterdam underground. The team will connect all the relevant stakeholders to develop a pilot methodology and a web portal connecting historic data sets for use in contemporary and future design. A book publication will document the process and outcomes, highlighting the need for circular practices that tie past, present and future.

Afgerond

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Towards Resilient Communities: Action Learning with SDGs as Compass

It is VHL’s mission to train high-quality, committed and innovative professionals who con-tribute to a more sustainable world , and who are able to organize and manage multi-stakeholder processes for sustainable change: graduates with transdisciplinary competences. Secondly, VHL aims to contribute to the SDG-agenda by linking its education and applied research to eight particular SDGs of which Resilient Communities is one. However, to operationalize SDGs in practice, and aligning targets and strategies of different stakeholders is difficult: ‘resilience’ and ‘sustainability’ refer to ‘wicked problems’ for which no definitive problem formulation, nor clear-cut solutions exist. Addressing wicked problems like ‘resilience’ and ‘sustainability’ requires transdisciplinary collaboration to manage and transform divergent values and conflicting interests, and to co-create sustainable innovations. This HBO postdoc views the 17 SDGs as a compass to align targets and strategies of citizens, government, civil society organizations, private sector and knowledge institutes who collaborate in Living Labs of VHL focusing on resilient communities/regions. Through spiraling action-reflection cycles, stakeholders will use the SDG compass to make success mechanisms, obstacles and trade-offs visible, assuming they stay engaged to overcome difficulties to improve interventions and innovations; this is expected to result in adapted sustainability practices and lessons learned on reaching community resilience. The postdoc’s aim is two-fold highlighting the link between research and education: (1) Design a methodology to integrate SDGs effectively in VHL’s applied research: using the SDGs as compass to improve performance and outcomes of transdisciplinary collaborations. (2) Develop a Roadmap for transdisciplinary education at course, curriculum, and institutional level with SDGs as compass. Future graduates require the competence to work together with others outside one own’s discipline, institute, culture or context. Living Labs offer a suitable learning environment to develop this competence

Afgerond

Producten 1.105

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Personal lighting conditions of office workers: An exploratory field study

MULTIFILE

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The future of lighting design beyond lighting design.

DOCUMENT

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Exploring the relationship between light and subjective alertness using personal lighting conditions

MULTIFILE