Occupants are often unaware of window opening strategies that can enhance their well-being and reduce energy consumption. Window feedback systems that indicate when to manually operate a window have become a strategy for enhancing the indoor climate, occupant’s satisfaction and energy efficiency. These systems are recognized for providing the comfort benefits of manual window controls while providing the efficiency benefits of completely automated windows (Bordass et al., 2007; Day et al., 2020). However, there is a lack of evidence to what extent window feedback systems are able to provide a successful cooperation between occupants and windows which enhances energy efficiency, satisfaction levels and their well-being.

This research investigated the influence that ambient light window feedback systems can have on the indoor climate and occupants’ satisfaction in open-plan workplaces. The research focused on determining the effectiveness of these systems and on establishing design guidelines for further developments. To do so, an experiment was carried out which assessed an existing and new situation of an open-plan workplace. The existing situation served as a benchmark for the new situation in which an ambient light window feedback system was implemented.

The methodology is divided into two parts and consists of literature research and research by experimentation. The literature research formed the initial part of the study and provided important considerations for the experiment. In addition, it formed guidelines for designing the window feedback system. The research by experimentation part provided objective and subjective data to determine the effectiveness of the implemented window feedback system. In addition, the data helped in determining design recommendations for the further development of the window feedback system and its algorithm. The outcome of the research shows that ambient light window feedback systems can be promising inside open-plan workplaces.

Nowadays, air ducts components for ventilation used in offices, hospitals and schools are made from non-renewable materials mainly sheet metal and plastics. Continuing to feed the high demand of metals is a challenge and could result of depletion of natural resources. This raises the importance to look into renewable resources with a lower environmental impact and contribute to the transition towards a circular economy. By rethinking the material usage for the duct components, solutions should be found in bio-based materials such as agricultural waste, cardboard, bio-composites or bio-plastics.

This research aims to explore the potential and limitations of bio-based materials for the applicability of air duct components. Therefore the following research question is formulated: What are the potential and limitations of bio-based materials to replace sheet metal for the construction of air ducts by maintaining the same quality?

Relevant literature reviews are conducted to give an understand of the construction and relevant requirements of sheet metal ducts. As well the circularity approaches and the categorization of bio-based materials and related manufacturing methods. A method is developed to classify the bio-based materials according their manufacturing efficiency per type of duct component: linear component, joint, bend and t-component. In addition, an assessment is described based on key criteria to select a suitable material per duct component in which the carbon footprint assessment and comparison is crucial.

In conclusion, the potential for linear bio-based components made from Tetra Pak is more advanced than complex components including joints, bends and t-components. This relates to the production efficiency and the LCA of the analyzed materials. Bio-plastics and composites as potential materials for complex components resulted in a relative high carbon footprint which made recycled plastic as non-renewable material a more realistic alternative.
The limitations lie by achieving a similar quality as sheet metal in terms of moisture resistance and chemical emission. Due to the porous character of most bio-based materials they are sensitive for humidity, increasing the risk of mold growth overtime making the use of bio-based materials and the design of the connections between components challenging. Furthermore, the lifespan of the bio-based materials is unknown which is crucial for an accurate LCA in terms of carbon footprint. Low lifespan indicates more replacements leading to potentially a higher carbon footprint overtime compared to sheet metal.

The building industry accounts for almost 40% of the total carbon emissions that are directly responsible for climate change. So far, we have been following a linear economy model which follows a concept of “take-make-use-dispose” and causes a significantly large burden on the natural environment. For this reason, transition to a circular economy is important in order to keep the resources in the economy for as long as possible, and thus reduce this burden. With a rising building stock reaching its end of life, the number of renovations in the coming years will increase significantly. They are expected to reach 35 million in 2030. The main focus of these renovations will be to make buildings energy efficient. While we have been successful in reducing the operational carbon of buildings, there is still scope to reduce the embodied carbon. This is also the main motivator for circularity goals.

It is estimated that the façade may account for between 13 and 17% of the total embodied carbon associated with a building. There is however not a strategic process to designing a circular facade. The methodology followed is the research-through-design methodology.

This project develops a design framework through studying existing literature, taking into account existing examples and pilot research projects - Circl Pavilion, CRL. The process uses the 10R strategy - particularly the cases of Reclaim, Recycle, Reuse, Reduce. This is then applied to the case of Building 22 at the TU Delft campus, and 4 options are developed. The evaluation through a life cycle assessment and building circularity approach is conducted on the platform OneClickLCA. It was found that for a circular design, material selection is very important. Overall materials with a lower embodied carbon should be selected. Moreover, materials with a higher volume of reused content should be prioritized first and a higher volume of bio-based content should be prioritized second. There is also a need to document and create more technical information for circular materials.