This research examines the impact of participatory planning on the realisation of public interests in urban regeneration, establishing an analytical framework to assess how participation shapes spatial transformations. Focusing on Taipei, it investigates the roles of public and private actors, statutory participatory processes, and resulting spatial changes. Two primary objectives guide the study: proposing a framework for assessing participatory processes and spatial outcomes and analysing Taipei’s diverse urban regeneration approaches—private-led, public-led, and social housing as a regeneration strategy. Six key questions explore literature on participation, evaluation indicators, policy evolution, implementation practices, spatial influences, and the effects of statutory methods like public hearings. Grounded in communicative planning thought, the research introduces the Inclusive Radar, adapted from Fung’s Democracy Cube, with axes for Participant, Communication and Decision-Making, Authority and Power, and Spatial Transformation. Employing case-study methodology, it integrates semi-structured interviews, site visits, meeting notes analysis, and cross-case comparisons. Findings reveal property-owning stakeholders’ dominance, marginalising non-property-owning stakeholders despite participatory processes. Private-led projects prioritise procedural compliance, public-led ones mediate via community planners but hinge on owners’ consent, and social housing fosters distrust through ambiguous participation. Overall, structures favour property rights, sidelining broader public interests like accessible facilities and green spaces. The study concludes that pre-assumed public interests restrict participation, with policy shifts emphasising property rights transfer and real-estate incentives. The Inclusive Radar offers a multidimensional tool for future applications, advocating policy reforms, capacity-building, and stronger public interest definitions to enhance inclusivity.
Human Creative Capital has become a key driver of urban competitiveness in the knowledge economy. However, metropolitan areas worldwide are experiencing diminishing appeal to young talents, with both high housing prices and poor housing quality being key contributing factors. This study investigates the decision-making mechanisms underlying young talents’ intercity migration and housing choices in China’s first-tier cities. While previous research has largely relied on neoclassical economic theories assuming rational decision-making, this study employs behavioral economics (Prospect Theory), psychological framework (Theory of Planned Behavior), and sociological perspective (Bourdieu’s Practice Theory) to examine how human agency shapes migration and housing decisions under uncertainty. Through mixed methods combining surveys and interviews, the research explores four questions following an “Aspire—Adapt—Anchor” narrative, investigating why young talents are drawn to these cities, how they navigate the housing market, and what influences their housing purchase and long-term settlement decisions. The findings extend conventional economic models in three significant ways. First, beyond traditional economic factors, the aspiration for self-actualization emerges as a key driver attracting young talents to first-tier cities, mediated through distinct psychological mechanisms. Second, their housing pathways reflect the dynamic interaction between structural constraints and individual agency, with different combinations of habitus and capital leading to diverse housing strategies. Third, while these young talents are initially drawn to first-tier cities, they show heightened sensitivity to potential losses in career prospects and housing costs, with their settlement intentions significantly anchored by institutional endowments such as public sector employment and housing tenure. Current housing situations and future migration prospects mutually shape their decision-making in metropolitan areas. By illuminating these psychological mechanisms in young talents’ major life decisions, this research suggests that policy interventions targeting psychological factors may be more cost-effective than traditional infrastructure-based approaches in talent retention.
The Architecture, Engineering, and Construction (AEC) sector is a major contributor to CO₂ emissions and resource consumption. In response, the Netherlands aims to make the sector 50% circular by 2030 and fully circular by 2050. However, the transition from a linear to a circular economy is complex due to technical, organisational, and cultural barriers. This dissertation explores how interorganisational behaviour and routinised practices within and beyond construction projects influence the realisation of circular ambitions. This research highlights the importance of top-down support, equal partnerships, shared goals, and intrinsically motivated individuals in construction projects. Trust, transparency, flexibility, and a shared team identity further foster the redefinition of traditional roles so as to drive innovation. However, factors such as focus on short-term cost and risk aversion often hinder progress. The dissertation further combines Sustainability Transitions Research (STR) and Social Practice Theory (SPT) into crossover frameworks that capture both systemic change and everyday practices. These are used to analyse (mis)alignments in the system-of-practices around construction projects. It was found that using secondary materials often clashes with notions of quality, safety, and aesthetics. Increasingly, Circular Building Hubs (CBHs) are brought forward as answer to this problem. This research shows that these hubs can be accelerators in the transition, though they are seen as temporary rather than permanent solutions. Ultimately, no single intervention will enable the shift to circularity. Instead, multiple coordinated changes in practices are needed. This dissertation provides tools for researchers and practitioners to navigate this complexity and encourages learning, experimentation, and a systemic approach to support sector-wide transitioning.
Existing buildings are changing assets, altered in response to various external or internal triggers for change. Often, change can occur in the form of adaptive reuse – also known as building transformation. Therefore, promoting adaptability in transformation is necessary to cope with the inevitability of building changes. Building transformation is considered an effective practice contributing to the circular economy (CE) and building adaptability as a prerequisite for circular design. However, previous research pointed out that building stakeholders lack knowledge about the alignment between CE and adaptive reuse. This study aims to provide building and real estate practitioners with a guiding framework for promoting circularity and adaptability in adaptive reuse projects. A quadrant research design was used in this study to develop and apply the framework in practice. The four components of this research are four stepwise studies, namely theoretical – an integrative literature review, empirical – multiple case studies, participatory – framework co-development, and actionable – framework implementation. First, the integrative literature review contributed to theoretically conceptualizing the underlying concept of this research – the circular building adaptability (CBA), which brings together circularity and adaptability. Second, the multiple case studies contributed to extracting lessons learned about applicable CBA strategies in adaptive reuse and their enabling and inhibiting factors. Third, the participatory study contributed to co-developing a descriptive framework for CBA in adaptive reuse (CBA-AR). Finally, the action research study contributed to testing and improving the usability and effectiveness of the CBA-AR framework based on observing, acting, and reflecting on a case project.
Urban infrastructure and the essential services it provides – energy, housing, transport, waste management, and water – are fundamental for human and ecological wellbeing. As urban populations grow, particularly in the Global South, equitable and sustainable service delivery is increasingly identified as a strategy for addressing both environmental and socioeconomic development challenges. Existing frameworks for sustainability transitions often prioritise technological innovation at the expense of social, political, and organisational dimensions of infrastructure. Likewise, mainstream approaches to infrastructure development favour large-scale, centralised, technology-driven solutions, overlooking the diverse service delivery arrangements that characterise many Southern cities. This thesis addresses this gap, combining empirical case studies with critical discourse analysis to explore how community-led and hybrid service delivery models contribute to inclusive and sustainable urban development. First, it examines how academic and policy discourses reveal a bias towards technocentric, Global North-focused perspectives on sustainable infrastructure. Next, it draws on case studies from 14 cities from across Africa, Asia, and Latin America to explore the delivery of essential services by community-based organisations, cooperatives, and informal service providers. Often considered “unorthodox,” such models can – given appropriate state support – contribute to improving service accessibility, mitigating environmental impacts, and empowering marginalised communities. Finally, these findings are used to propose refinements to sustainability transitions theory, including the Multi-Level Perspective. The thesis concludes that policy, practice, and academic theory must shift away from a narrow emphasis on technological solutions or economic efficiency, embracing broader approaches to urban service delivery that can benefit both human wellbeing and environmental sustainability in cities worldwide.
Recent geopolitical events have driven a sharp rise in gas prices, making it increasingly difficult for households to heat their homes affordably and comfortably. Additionally, the environmental consequences of fossil fuel-based heating underscore the urgency of transitioning to more sustainable alternatives. In response, the Dutch government has set an ambitious target to eliminate natural gas heating in 1.5 million homes by 2030, emphasising the need for viable solutions. District heating (DH) systems, particularly those providing lower-temperature heating (LTH), offer a promising alternative—delivering sustainable and cost-effective heating, especially in densely populated areas. However, with their high heating demands, many existing homes require significant renovations before efficiently transitioning to LTH-based systems. The selection of appropriate renovation strategies is complex, often leading to uncertainty and delays. This research tackles the challenge of preparing Dutch homes for LTH by developing a systematic decision-support framework using a mixed-methods research approach. It is structured around four key research activities. First, it identifies and analyses the critical factors influencing building characteristics, available renovation options and performance indicators. Second, it defines LTH readiness, prioritises thermal comfort and energy efficiency at reduced supply temperatures, and uses a two-step evaluation method to assess a dwelling's readiness and identify necessary interventions. Third, recognising the diversity within the Dutch housing stock, probabilistic sampling and machine learning analyses were employed to quantify the relative significance of building features affecting LTH readiness, accounting for variations across dwelling types. Finally, a structured six-step decision support framework based on multi-criteria decision-making (MCDM) methods was developed and validated through real-world case studies and stakeholder workshops. By providing a clear and actionable decision-support framework, this thesis facilitates energy renovation planning, accelerates the transition to gas-free heating, and contributes to the Netherlands' broader sustainable energy goals.
In alignment with Sustainable Development Goal (SDG) 11, particularly Target 11.3 on inclusive and sustainable urbanization, many countries and regions now regard public participation as a cornerstone of human settlements planning. China’s recent neighborhood rehabilitation initiatives likewise prioritize resident engagement, though the COVID-19 pandemic has introduced new obstacles and reconfigured participatory processes. Against this backdrop, this thesis investigates resident participation for neighborhood rehabilitation in post-pandemic China. Drawing on established theories of public participation and neighborhood revitalization, it proposes a conceptual framework centered on stakeholder concerns, power relations, and information sharing, and examines mechanisms that foster sustained resident involvement. Wuhan, a developing city and the initial epicenter of COVID-19, serves as the case study. Results identify 37 key concerns, each subject to varied stakeholder perceptions. Power operates through multiple channels, shifting across project phases. Despite frequent information sharing, exploitation and competition persist. Organizers, particularly community-based organizations, play a critical role but face resource constraints, shifting power dynamics, and information manipulation. Straightforward participatory activities, early engagement, and greater influence increase resident willingness to stay involved. Nevertheless, opacity and exclusion, amplified by power imbalances and selective information control, remain pressing issues. Synthesizing the lessons and insights, the thesis concludes with short- and long-term measures to “enhance inclusive and sustainable urbanization and capacity for participatory, integrated, and sustainable human settlement planning and management (SDG 11.3).”
University students are self-directed learners who dedicate considerable time to studying in study places. Research on indoor environmental quality (IEQ) highlights the adverse effects of prolonged indoor exposure to environmental stressors, including noise. Acoustical quality can significantly influence students’ health and comfort. To evaluate the acoustical quality of study places, three groups of indicators can be considered: occupant-related, dose-related, and building-related indicators. Given that students have different acoustical and psychosocial preferences for study places, it is crucial to consider occupant-related indicators. However, existing acoustical guidelines for study places and educational buildings primarily focus on dose-related and building-related indicators, while occupant-related indicators have been overlooked. Therefore, the main research question of this dissertation was posed: How to assess the acoustical quality of study places? This question was answered through several research methods. First, a literature review identified indicators and methods used to study students’ acoustical preferences and needs. Then, ‘MyStudyPlace’ questionnaire was completed by university students who were clustered based on their IEQ and psychosocial preferences, resulting in nine profiles. Subsequently, students were re-clustered based on acoustical and selected psychosocial preferences, resulting in five profiles. To further explore these profiles, 23 home study places were visited, incorporating interviews, building inspections, and sound pressure level measurements. After that, 15 of these students participated in sound exposure lab experiments, which involved bodily responses, audiometric tests, and perceptual assessments. Furthermore, an indoor soundscape approach using semi-structured interviews with the 23 students examined their sound environment experiences of their home study places. This dissertation offers future research a set of suggested methods and indicators to assess the acoustical quality of study places.
Since the financial crisis of 2008, National Statistical Institutes (NSIs) have worked to develop commercial real estate (CRE) indicators for official statistics. These indicators are considered essential in financial stability monitoring and may help contain the consequences of future crises or even prevent future crises. However, progress at NSIs to develop these indicators has been slow due to challenges like low observation numbers and high heterogeneity. This dissertation addresses these challenges by exploring data issues and suggesting methodological improvements. The first three studies focus on data challenges regarding share deals and portfolio sales. Both are real estate trading constructions that are specific to CRE. The results show that share deals and portfolio sales significantly differ from the rest of the market. Therefore, under specific circumstances, CRE indicators could benefit from including these trading types. The final two studies focus on methodological challenges regarding index construction methods and the role of sustainability in real estate pricing. The results show that, by combining established techniques, it is possible to construct price indices that meet official statistics’ standards. Furthermore, the results uncover a complex relationship between sustainability and prices: while energy efficiency generally involves price premiums, others aspects like health and environment display a discount for low sustainable properties. Overall, this dissertation contributes to the legislative framework that is currently being developed for EU countries to publish official statistics for commercial real estate and adds to the academic discussion by presenting innovative techniques for data analyses and index construction.
This thesis investigates the practical connection between health-promoting evidence and the spatial design of blue spaces. This endeavour aims to develop instrumental resources that facilitate the integration of the health benefits of natural environments into actionable strategies, thereby augmenting the development of design research and enhancing understanding of the nature-health nexus. The research methodically examines three interrelated aspects: understanding the academic contexts and methodological preparation from the design perspective, development of qualitative and quantitative design knowledge for fulfilling health benefits of blue spaces, and applications and reflections on proposed knowledge through design workshops and interviews. Initially, the thesis outlines the relationship between blue space and health from a design perspective, identifying a significant, unexplored gap. It then proposes a methodological framework to translate health-promoting evidence of blue spaces into design knowledge for practices. Subsequently, this thesis employs interdisciplinary techniques, integrating both qualitative and quantitative approaches, to generate varied types of design knowledge, including distilling worldwide precedent cases, summarising diverse geospatial and visualisation tools, and translating site-based evidence using spatiotemporal crowdsourcing data. The effectiveness and usability of the proposed knowledge are evaluated through design workshops, complemented by expert interviews across various fields, providing insights that reflect on the research outcomes and suggest future directions. Overall, by focusing on the interactive relationship between research and design, the principal contribution of this research lies in its attempt to translate theoretical evidence from public health into practical design interventions, exploring the potential of interdisciplinary tools and methods in facilitating this process.
As cities across the globe grapple with rising urbanisation and housing shortages, over one billion people now reside in informal settlements. In South Africa, the legacy of apartheid planning, combined with systemic inefficiencies and rapid urban growth, has compounded the challenges of providing inclusive, sustainable low-income housing. While extensive research exists across disciplines such as architecture, political science, and economics, much of it remains siloed—offering fragmented perspectives on an inherently complex issue. This dissertation takes a different approach. It examines low-income housing through a double lens: spatial design—how built form is created and how its context is developed—and governance—the aims, actors, and instruments involved in decision making. Using the K206 housing project in Alexandra, Johannesburg, as a case study, the research explores what happens when government plans meet residents’ lived experiences. It engages three key literature themes of low-income housing: informal settlement upgrading, state-subsidised housing, and incremental housing. Through interviews, surveys, and expert consultations, the research reveals how governmental aims—such as resident-responsive design, security of tenure, and income generation—were translated into built form, and how residents responded to and reshaped these interventions—sometimes in unexpected ways. The findings show that residents are not just recipients of housing policy—they actively reshape their environments and create their own systems of living, especially when dissatisfied with the systems they are dealt. The research highlights governance and spatial design complexities in South Africa and makes the case for interdisciplinary approaches that centre the voices of those most affected by housing policy.
Climate change affects cities in every region of the world, and cities need to improve their urban resilience. Resilient measures are often implemented in public spaces because they are the urban voids in which infrastructures, water, biodiversity, mobility, and human life unfold. However, their institutional settings often make their design processes significantly challenging. Many complexities must be agreed upon and integrated into designing resilient public spaces. Taking a collaborative approach to designing public spaces has been said to improve their resilience by involving different actors and integrating their aims and knowledge. However, the mechanisms to do so remain unclear. This research explores how a collaborative approach can contribute to the design processes of resilient public spaces. It does so in the geographical context of Chile, a territory prone to diverse climate change impacts. It poses that revised urban design processes are crucial for implementing resilient public spaces. It focuses on co-design processes and their mechanisms and methods to integrate the diverse knowledge backgrounds of the involved actors. The studies examine the co-design processes of prominent resilient public spaces in Chile and design one in the same context. This research aims to contribute to urban design by formulating a comprehensive framework and guidelines for designing resilient public spaces collaboratively. It contributes generalisable and context-specific findings with particular emphasis on the Chilean context.
This research aims to reveal and explore the commonalities and differences in the definition of interventions on built heritage between theory and practice, using new aspects—cultural values and attributes of cultural significance—to support the definition process. A comparative approach is employed to discuss how different interventions are defined in international doctrines and applied in a local project, including stakeholders’ perspectives. International organizations have adopted doctrinal documents that promote best practices in heritage management. However, these doctrines are difficult to compare and apply. Due to the lack of alignment in definitions between doctrines and the lack of research on how cultural values and attributes of cultural significance influence the definition of interventions. In filling these gaps, the main research question was asked: What are the trends of interventions and their definitions under the influence of cultural significance, as scoped by international doctrines between theory and practice? The research utilized theoretical frameworks on cultural values and attributes and analyzed documents and interview transcripts from the National Gallery Singapore. The main findings indicate the diversity in defining interventions at the international level. Values play a dynamic role in shaping intervention definitions, whereas attributes influence them in a hierarchical pattern. At the local level, stakeholders' perspectives on definitions are shaped by the local context and a mindset of "practicality." This research concludes that Singapore follows international trends while locally customizing and evolving its definitions. This research proposes a possible novel approach to defining interventions in built heritage that bridges theory and practice.
This research is a component of the 2ALL Addis Ababa Living Lab project, which focuses on creating resilient dwelling clusters for urban resettlement in Addis Ababa, Ethiopia. Funded by NWO-WOTRO, the project explores innovative housing approaches aligned with the overarching Sustainable Development Goal (SDG) of building sustainable cities and communities. Reconstructing Dwelling examines dwelling culture in relation to housing conditions within both planned and unplanned neighbourhoods of Addis Ababa. Ethnographic methods are employed to study housing practices across various housing development models, focusing on layers of dweller-initiated housing transformations to uncover patterns of habitation. The study also conducts a comparative analysis of the temporalities that are present in the adaptations made by residents. These transformations are visually reconstructed and documented through ethnographic surveys, culminating in a pattern catalogue to identify and redefine key socio-spatial patterns that shape the culture of dwelling in Addis Ababa: The gibi, gwaro and gwada. Rooted in the principles of alternative epistemologies, the study emphasises these patterns as critical elements informing dwelling design. It reveals the links between these patterns and dweller-initiated transformations, showcasing their essential role in space-making. Consequently, the research contributes to rethinking architectural pedagogy, practice, and policy in a more contextually grounded and inclusive manner. By situating itself within contemporary challenges, Reconstructing Dwelling builds a body of knowledge aimed at developing inclusive and resilient dwelling clusters. This approach offers an alternative to the current disruptive resettlement practices in Addis Ababa, which often undermine livelihoods and disregard existing socio-spatial patterns.
In response to the WHO and UN’s call to ensure children’s right to breathe “clean” air and the challenges posed by the COVID-19 pandemic on maintaining healthy indoor air quality (IAQ), this PhD research explores ventilation and air cleaning strategies to control the spread of infectious respiratory particles (IRPs) in school classrooms. The study follows four key steps: (1) a literature review bridging school ventilation regimes, IRP transmission, and advanced ventilation systems; (2) a field study to evaluate real-world ventilation and thermal conditions during the pandemic; (3) an experimental investigation of performance of mobile air cleaners (MACs) followed by an in-situ validation; and (4) a combined experimental and computational study to assess personalized air cleaners (PACs) as localized exhaust for IRP removal. Findings reveal that most classrooms rely on natural ventilation, often failing to meet IAQ standards, especially when fully occupied. With windows and doors open, ventilation rates remained inconsistent, and thermal conditions were unsatisfactory. Hence, more controllable ventilation and air cleaning approaches are needed. MACs, when appropriately selected and positioned, offer effective protection against long-range IRP transmission at room scale, while PACs are effective at mitigating localized, short-range IRP exposure, improving IAQ at an individual level. This research offers a comprehensive set of solutions for IRP control in classrooms, with actionable insights for a variety of stakeholders. It advocates for a shift from comfort-based to health-centered paradigms. Future research should explore hybrid systems, optimize designs, and validate interventions through real-world infection risk assessments to create healthier, more resilient classrooms.
In recent decades, the housing shortage and multi-dimensional housing challenges, including lack of physical quality, accessibility to urban amenities, lack of social characteristics and habitability conditions, have increased worldwide. In Latin American countries faced with some of these challenges, many governments have formulated a wide range of policies and housing programs. In Chile, the State has delegated housing production to private companies. This approach has mostly affected the location, quality, and social dimension of housing. In other urban contexts, such as in some European countries, inhabitants facing similar issues have self-organised to develop their homes driven by pragmatic and radical goals. From a Global North perspective, these initiatives, characterised by collaborative processes between future residents and external stakeholders in housing production, are labelled under the umbrella term of Collaborative Housing. In Latin America, there is also a long tradition of self-organisation in housing through self-building and self-management processes. In Chile, there has been recent interest from resident groups, third sector organisations and the current government in promoting collective self-organised housing through specific programs. However, the concept of collaborative housing has been mainly researched and theorised from a Global North perspective. Furthermore, the meaning and potential of collaborative housing to address housing deficits from a multi-dimensional standpoint have received limited attention in academic research in Chile. This PhD research fills this knowledge gap by applying the collaborative housing concept to study collective self-organised housing in Chile. To this end, it proposes a conceptualisation of ‘Collaborative Housing’ in the Latin American and Chilean context and determines its dimensions. It also investigates its opportunities and limitations when addressing the Social Deficit of Housing, plans scenarios, and proposes policy strategies. The research applies mixed methods, including a policy review, case studies, interviews, and Delphi-based scenario questionnaires. This dissertation concludes with scenarios and long-term policy strategies for three collaborative housing models emerging in the country: cooperativas cerradas de vivienda, pequeños condominios, and vivienda colectiva. It also provides recommendations that serve as a guide to stakeholders interested in implementing collaborative housing.
This dissertation develops an understanding of circular built environment policies. It draws of Jo Williams’ Circular City Development and Måns Nilsson et al. Policy Coherence analysis Framework to propose a framework for ex ante circular city policy coherence analysis, which is developed and tested through three case studies: campus development at TU Delft (Netherlands), circular built environment policy in Greater London (UK), and mass timber construction policy in Amsterdam (Netherlands). The dissertation uncovers policy formulation by means of circular economy policy objectives, instruments and implementation practices. It shows that in the selected case studies, circular economy policies are increasing their coherence by means of supply chain and business driven circular economy frameworks, but less so in developing circular urban systems. Currently, the circular built environment policies analysed throughout this dissertation are based on looping actions (e.g., recovery, recycling, reusing) and tend to overlook ecological regeneration actions (e.g. blue and green infrastructure and urban ecosystem services provision) and adaptation actions (e.g. community-led co-creation and capacity building). Ultimately, this dissertation argues that current circular built environment policies ‘cannot see the city for the buildings’ and that ex ante evaluation of circular city policies can contribute to improve the alignment and synergies between policy objectives, instruments and implementation practices towards circular city development.
Housing markets have produced structural inequalities evident in the unaffordability issues experienced by many households across Europe. Over the past century, housing has shifted from a domain of strong government intervention to one increasingly influenced by market forces. Today, as Europe decarbonises, not only affordability but also sustainability have become central to housing debates. This dissertation investigates how decarbonisation policies affect both housing affordability and provision. Following an essay-based structure (capita selecta), this thesis brings together studies on fiscal policy, sustainable finance, and social housing provision across various European settings. The dissertation is divided into two main parts. Part I, Affordability and Costs, employs quantitative methods to assess the economic impacts of decarbonisation on households. Part II, Provision and Finance, takes a qualitative approach to examine financing mechanisms for decarbonisation and social housing provision. While each part draws on distinct methodologies, together they provide an overview of how certain decarbonisation policies interact with housing systems at both household and structural levels. The findings show that current decarbonisation policies often favour wealthier homeowners through subsidies and tax incentives, while having a negative or mixed impact on renters, younger households, and low-income groups. To address these challenges, the thesis advocates for redistributive fiscal reforms—such as energy efficiency-linked property taxes—and stronger public institutions and regulations to guide investment towards equitable and sustainable housing provision. By placing affordability at the centre of decarbonisation policies, this dissertation aims to inform the development of transitional pathways that align both social and environmental goals.
This thesis explores different ventilation systems used for operating rooms (OR). Entrainment test methods are used in most European standards to determine the protected zone whereas the air quality in the periphery is often excluded. Furthermore, these measurements are mostly carried out in an at-rest situation where intermittent sampling during operation should be required. Most ORs in the Netherlands have an air handling system with an ultra-clean ventilation system (UCV). ORs are energy-intensive departments, where air handling systems consume the most. Relatively simple adjustments can be made to the air handling system to reduce energy, such as expanding relative humidity limits and introducing operational clock times. Lowering outside air quantity has the biggest impact on energy reduction, lowering the OR classification the least. Reducing the air change rate in the OR from an ultra-clean to a generic OR will reduce the recovery degree and the local air change rate. Lowering the air change rate in operating rooms could harm comfort conditions and (ultra-clean) air quality. The capital and operational expenditures of air handling installations with an UCV-system are higher than those with a conventional system. The investment pays for itself when 2 to 4 surgical wound infections are prevented over the lifetime of the OR. The type of surgery should be a leading consideration in determining the typology of the air handling system and the type of air supply system. Absence of evidence that surgical site infections are prevented in ORs equipped with UCV-systems is not evidence that these are not prevented.
At present, agriculture is confronted with the significant challenge of increasing production to meet escalating global food demands, while simultaneously dealing with reduced land and resource availability. Moreover, there is an imperative need to lower greenhouse gas emissions for climate change mitigation. In response to these agricultural challenges, vertical farming has emerged as an evolving agricultural method designed to enhance productivity while minimising resource usage and environmental impact. Vertical farms achieve this by cultivating crops in vertically stacked hydroponic systems within an uniformly controlled indoor environment using active climate control systems and artificial light. Through this approach vertical farms operate independent of external climate factors and produce stable year-round yields. Vertical farming is often advocated as a sustainable food system, as they offer several benefits over conventional farming systems, including efficient land use, high yields, minimal water and nutrient usage, the redundancy of pesticides and herbicides, and the ability to be located within or adjacent to cities where food demands are high. However, a major challenge for vertical farming is the substantial electricity use for artificial lighting and climate control. Despite this drawback, literature recognises vertical farming as a potential strategy to enhance energy and resource use efficiency in both agriculture and cities by creating synergies between both entities. This study, centred in the Netherlands, addressed the research question: How can the synergetic integration of vertical farms within cities reduce energy and resource usage as well as carbon emissions of both entities collectively? The primary focus of the study was the exchange of residual heat produced by VFs with the cold generated when heating buildings in the city, i.e., energetic synergy. To evaluate the potential of vertical farms to grow food in a sustainable way, this study extended beyond efficient land use and high yields, considering the entire life cycle of the crops cultivated in vertical farms. A carbon footprint assessment compared lettuce produced in an operational vertical farm to open-field farming and greenhouse cultivation in the Netherlands. The findings revealed that the substantial electricity use for artificial light and climate systems outweighed the aforementioned benefits of vertical farming from a carbon footprint perspective. The high electricity use for artificial light results in the production of substantial quantities of waste heat. Starting at the building scale, we explored how this heat can be captured and reused for building heating. Furthermore, the potential to exchange flows of water and nutrients between the building and the vertical farm (to reduce the need for external inputs) were studied. On the larger urban scale, the possibility to create thermal energetic equilibrium within the local district heat networks using the excess heat from vertical farms was analysed. Moreover, we explored alternative lighting strategies for vertical farms to respond to electricity price fluctuations, addressing imbalances between electricity generation and consumption in the electricity grid, while ensuring the continuous production of fresh vegetables for the city. Finally, we evaluated the potential benefits of integrating vertical farms with urban energy systems in terms of an overall carbon footprint. To this end, a carbon footprint assessment was performed for four different scenarios for the city of Amsterdam, ranging from a reference city relying on conventional farming methods and existing energy systems, to a city using residual heat from vertical farms that simultaneously attune their electricity use with the availability of renewable energy in the grid. The findings revealed that this attuned and synergetic integration of vertical farms with urban energy systems effectively reduced the collective energy use of both the vertical farm and the city, lowering the carbon footprint of vertical farms in cities. However, despite these carbon savings, the overall carbon footprint of such a synergetic city still surpassed that of cities relying on fossil-based heating and conventional farming for vegetable and fruit consumption. Although the energy used for heating was reduced by the integration of vertical farms, the overall increase was still attributed to the substantial energy use for artificial light to cultivate crops in vertical farms. Furthermore, the study highlighted the need for careful consideration of location, crop selection, light use efficiency, and the use of residual heat to minimise the additional carbon emissions by the integration of vertical farms into cities. The observed increase in greenhouse gas emissions should be weighed against the potential benefits vertical farms bring to cities, including enhanced food security, self-sufficiency, replacement of fossil-based heating systems, efficient land use, and the flexibility offered to the electricity grid by attuning the LED lighting according to the availability of energy, reflected in the electricity prices. Finally, the study revealed a trade-off between carbon footprint reduction and the essential need for flexible electricity operations in cities. Attuning LEDs to enhance grid stability, while crucial for cities, increases the carbon emissions of vertical farms. In summary, the synergetic integration of vertical farms presents substantial benefits for cities in terms of crop production, land use, flexible electricity utilisation, and heat supply. However, when focussing on the carbon footprint, vertical farms, even those in synergy with the city, face a significant challenge in competing with conventional farming systems due to the substantial use of electricity for lighting. Further development of effective lighting systems, perhaps hybrid with use of daylight, might leverage this backlash.
