Thermal comfort is determined by the combined effect of the six thermal comfort parameters: temperature, air moisture content, thermal radiation, air relative velocity, personal activity and clothing level as formulated by Fanger through his double heat balance equations. In conventional air conditioning systems, air temperature is the parameter that is normally controlled whilst others are assumed to have values within the specified ranges at the design stage. In Fanger’s double heat balance equation, thermal radiation factor appears as the mean radiant temperature (MRT), however, its impact on thermal comfort is often ignored. This paper discusses the impacts of the thermal radiation field which takes the forms of mean radiant temperature and radiation asymmetry on thermal comfort, building energy consumption and air-conditioning control. Several conditions and applications in which the effects of mean radiant temperature and radiation asymmetry cannot be ignored are discussed. Several misinterpretations that arise from the formula relating mean radiant temperature and the operative temperature are highlighted, coupled with a discussion on the lack of reliable and affordable devices that measure this parameter. The usefulness of the concept of the operative temperature as a measure of combined effect of mean radiant and air temperatures on occupant’s thermal comfort is critically questioned, especially in relation to the control strategy based on this derived parameter. Examples of systems which deliver comfort using thermal radiation are presented. Finally, the paper presents various options that need to be considered in the efforts to mitigate the impacts of the thermal radiant field on the occupants’ thermal comfort and building energy consumption.
Thermal comfort in operating theatres is a less addressed research component of the in-door environment in operating theatres. The air quality naturally gets most attention when considering the risk of surgical site infections. However, the importance of thermal comfort must not be underestimated. In this research, the current thermal comfort situation of staff members is investigated. Results show that the thermal comfort for the members of a surgical team is perceived as not optimal. Application of the PMV and DR models needs further attention when applied for operating theatres. For the investigated ventilation systems, the differences in thermal comfort outcomes are small.
In indoor comfort research, thermal comfort of care-professionals in hospital environment is a little explored topic. To address this gap, a mixed methods study, with the nursing staff in hospital wards acting as participants,was undertaken. Responses were collected during three weeks in the summer (n = 89), and four weeks in the autumn (n = 43). Analysis of the subjective feedback from nurses and the measured indoor thermal conditions revealed that the existent thermal conditions (varying between 20 and 25 °C) caused a slightly warm thermal sensation on the ASHRAE seven point scale. This led to a slightly unacceptable thermal comfort and a slightly obstructed self-appraised work performance. The results also indicated that the optimal thermal sensation for the nurses—suiting their thermal comfort requirements and work performance—would be closer to‘slightly cool’than neutral. Using a design approach of dividing the hospital ward into separate thermal zones, with different set-points for respectively patient and care-professionals’comfort, would seem to be the ideal solution that contributes positively to the work environment and, at the same time, creates avenues for energy conservation.
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.
Thermoset materials find use in almost all industrial sectors, especially where lightweight, stiffness, resistance and dimensional stability are key performance requirements. However, traditional thermosets suffer from several drawbacks: they are made of fossil-based non-reversible polymers and toxic monomers; more importantly, thermosetting materials are virtually neither recyclable nor reprocessable, due to their crosslinked microstructure. Currently, most thermoset materials are incinerated or accumulated in landfills at the end of their life. Landfill waste degrades to liquids known as landfill leachates that lead to health and environmental problems. A significant part of these wastes originate from thermoset materials used in paints, coatings, sealants and adhesives applied as a thin film to all sorts of surfaces. These unrecyclable materials contribute to nano- and microplastic formation. Despite many efforts in the past years in this context, substantial further developments are required. Production of thermosets from biobased feedstocks using safe and sustainable-by-design approaches is therefore crucial to address the well-being of people and to have a healthy planet.SMARTCASE aims to develop safe and circular carbohydrate-derived reactive polyester resins for coatings, adhesives, sealants and elastomers for application in the building and interior sectors. The new two-component (‘2K’) formulations are designed to replace currently used fossil-based epoxy and urethane resins by biobased and GHS-label-friendly alternatives. This not only improves the safety of workers and end-users of these materials, but also reduces the dependency on fossil resources and facilitates the transition towards abundantly available biobased raw materials.A new class of biobased polyesters resins and thermosets will be designed in SMARTCASE using safe and sustainable by design approaches allowing for more sustainable and feasible end-of-life options. Biobased polyesters in general meet the requirements of circularity, as they can be efficiently recycled back to their monomers at end-of-life. Accordingly, the recycling and degradation behavior of the developed formulations under thermal, mechanical and chemical conditions and their biodegradation will be studied. Hence, the output of the project contributes to the main goals of the NGF BioBased Circular program.The project follows a value-cycle approach with a multi-disciplinary and balanced consortium of industrial representatives from every part of the value chain, from carbohydrate feedstock suppliers to resin formulators and end users. This enables a system innovation instead of a (single) product innovation. The following results are expected within 10 years (mostly by the end of the project ): - Sustainable feedstock platform for novel biobased (BB) platform chemicals- Access to novel monomers and building blocks- Access to safe and novel polyester-based resin components- Access to high performance, safe and circular thermoset formulations- Scale-up of the best thermoset formulations- Validated performance of novel thermoset formulations in industrial applications- Sustainable and circular-by-design thermoset formulations with defined end-of-life solutions - Data on LCA, TEA, toxicity and sustainability- Engaged stakeholders and effective dissemination of project outcomes By ensuring these results are implemented by industrial partners both during and after the project, they will benefit not only stakeholders, chemical industries, and consortium partners but also the general public.
Living walls are increasingly becoming tools for green climate adaptation in the urban context, but distribution efforts are dampened by high investment and operational costs. Those costs are derived mainly from designing and manufacturing unique equipment for such new projects. A system using wastewater could relieve some of these costs by decreasing their irrigation and fertigation needs. Muuras is developing helophyte filters integrated into living wall systems that can readily be attached to any wall surface, with the ultimate purpose of local water recycling. Additionally, based on the fact that Muuras is a pre-engineered company, their product is modular, which means that a considerable advantage is recognized regarding the decreased capital cost. To realize scalable implementation of such a system, research with regards to the purification capabilities of lightweight substrates and small wetland plant species is imperative. In SoW & FloW, the NHL Stenden Water Technology Professorship proposes a collaboration between two SME’s (Muuras, Greenwave Systems) and a company (DeSaH), to evaluate a selection of substrates and endemic plant species based on their capability to use domestic wastewater as an irrigation source.
