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Energietransitie: omarm de complexiteit: Ontwikkeling en grootschalige toepassing van energieneutrale renovatieconcepten voor de naoorlogse sociale woningvoorraad
Get PDFThis book presents the outcome of research on conditions for development and large scale application of energy neutral renovation concepts, which can contribute to the transition towards an energy neutral post-war social housing stock. Two projects are studied of the innovation and transition program ‘Energy Leap’ (Energiesprong); ‘Slim & Snel’ and ‘De Stroomversnelling’. The aim of both projects was to stimulate the development and large scale application of energy efficient renovation concepts for the post-was serial built social housing stock. In doing so, they focus on product and process innovation, combined with industrialization, to make renovation concepts scalable and affordable.
Background
There is a large energy saving potential in the existing housing stock, which can contribute to a sustainable built environment. For decades people have been making homes more energy efficient. The current Dutch housing stock exist for one third of dwellings from the period 1945 till 1975 (Ministerie van Binnenlandse Zaken en Koninkrijkrelaties, 2016). Due to the large production of houses from housing associations at that time, a large percentage of their stock still consists of dwellings from this period. Post-war social rental housing is often in need of a major improvement, especially in the energy field. Agreements have been made within the social rental sector to bring the housing stock to average label B before 2021 (SER, 2013), as a step towards an energy neutral stock in 2050. However, the current pace of energetic improvements is still insufficient to achieve the objectives. A transition is needed. The slow transition to an energy-neutral housing stock can partly be explained by the existing structures and related ways of thinking and acting in construction. Housing associations are willing to make their property more energy efficient, but are limited by the deterioration of their financial position and the limitation of their duties in recent years. The ‘Energy Leap’ program, aimed at the realisation of an energy neutral built environment, tries to investigate, through experiments, where the system can be adjusted to make the transition. The transition path, or in other words the strategy to arrive at an energy neutral housing stock, which is used by Energy Leap, is the use of integrated renovation concepts that makes homes in one time energy neutral.
Research objective and questions
The objective of the research is to create insight into the conditions required for the development and large scale application of energy neutral renovation concepts. The research aims to contribute to the transition to an energy neutral post-war social housing stock. Based on this objective, the following main question has been formulated:
Which conditions are required for the development and large scale application of energy neutral renovation concepts, which can contribute to the transition to an energy neutral post-war social housing stock?
To answer this question, the activities of Energy Leap were studied that were focused on the post-war social housing stock. The first research question focuses on these activities of Energy Leap and the context in which they are undertaken. Subsequently, by conducting template analysis, actions are derived that contribute to the development and large scale application of energy neutral renovation concepts. By establishing links between the actions in relation to the transition, the researcher has come up with sets of coherent actions that relate to a specific part of the system. Based on these sets, the required conditions are formulated.
1. What activities have been undertaken from Energy Leap to accelerate the transition and in what context?
a. Which activities were there in the Netherlands prior to Energy Leap for far-reaching energy savings in the existing housing stock?
b. How is the Energy Leap program from which activities have been undertaken built up?
c. On which theoretical concepts are the ideas of Energy Leap about the acceleration of the transition based?
d. How are the activities of Energy Leap developed specifically for the development and large scale application of renovation concepts for the post-war social housing stock?
2. What actions can be distinguished from the activities of Energy Leap, which contribute to the development and large scale application of energy neutral renovation concepts?
a. Which actions contribute to the development of energy neutral renovation concepts?
b. Which actions contribute to the large scale application of the developed renovation concepts?
c. What are the mutual relationships between these actions?
3. What conditions can be deduced from the determined actions and underlying theoretical concepts for the development and large scale application of energy neutral renovation concepts?
Research approach
For the research a pragmatic approach is used. The research can be typified as participative, observational and inductive. By conducting participatory and observational research within the Energy Leap program, activities of Energy Leap were explored and the data collection was done for the analysis. At the same time, desk research was carried out into the energy policy from the 1970s onwards and the theoretical concepts which Energy Leap is based. Based on these theoretical concepts, lessons have been drawn that can contribute to the transition and that were later used for the comparison between theory and practice.
An inductive analysis, in the form of a template analysis, was carried out on the data that emerged from participatory and observational research, with which the actions were determined for development and large scale application of renovation concepts. The relations between the actions are also recorded.
The lessons from the theory were compared with the activities of Energy Leap and the derived actions. From the insights that resulted from this, a schematic image was formed about the transition process. With this image a rearrangement has been made in the list of actions that contribute to development and large scale applications of renovation concepts. This distinguishes sets of interrelated actions that relate to a specific part of the system. From these sets the necessary conditions are derived for the development and large scale application of energy neutral renovation concepts, which can contribute to the transition to an energy neutral post-war social housing stock.
Energy Leap: activities aimed at energy neutral renovation
Energy leap can be seen as a transition program with which steps have been taken to start the transition to an energy neutral housing stock. Energy leap saw its own role mainly in to make a movement in the market and the realization of the necessary conditions. Energy leap focused on the development of integrated, affordable and scalable concepts. Using these it wanted to make ascending steps of 45%, to 60% and 80% energy reduction and it finally advocated bringing homes to Zero-On-The-Meter in one go. Energy leap helped parties achieve this by focusing on cooperation and knowledge sharing. Hereby it focused on the leaders in the market. At the same time, it tried to remove obstacles at all levels and to work on new approaches and solutions.
Energy Leap has carried out various subprograms and projects with different approaches. There have been several tender projects supported by subsidy to create successful examples. Process support was provided to various projects, with the parties being guided in new ways of commissioning and integral cooperation. With a competition, a stage was given to innovative concepts. With deal making, agreements have been reached between parties to tackle large numbers of homes. Finally, knowledge products have been developed: tools for integral performance, financial feasibility and scaling up of concepts.
Various theoretical approaches have influenced the Energy Leap program. Energy Leap has been set up as an implementation program for an innovation agenda. This innovation agenda has been drawn up from an innovation system approach (Hekkert et al., 2007). The philosophy of the Energy Leap program was based on the ideas of Transition Management (Rotmans, 2003). This has been applied by carrying out various transition experiments and by taking up the role of intermediary. The ‘Slim & Snel’ projects have been set up from the experimental idea, creating a protective environment and experimental space at project level (Van den Bosch, 2010). ‘De Stroomversnelling’ has much more the characteristics of Strategic Niche Management (Kemp et al., 1998). In addition, different views on development, change management and group processes have had an influence. Within the ‘Slim & Snel’ projects, but also at ‘De Stroomversnelling’, the lessons from the Soft System Methodology (Checkland en Poulter, 2006) have been deployed and various lessons from the Merger of Interests perspective (Van Hal, 2014) can be recognized. Theory U (Otto Scharmer, 2009) was used as inspiration for upscaling and for the target groups used was made of Rogers classifications (Rogers, 2003).
Two subprograms of Energy Leap focused specifically on the post-war social housing stock, to which process support was given; ‘Slim & Snel’ and ‘De Stroomversnelling’. With Slim & Snel, Energy Leap strived for a series-based approach to accelerate the number of energy efficient housing renovations. In order to stimulate the development of integrated concepts, room for innovation has been created by using a different way of questioning and selection. Furthermore, it was required to work with multidisciplinary consortia that were coached in the cooperation in the chain to promote the integrality of the concepts. The scalability of concepts was pursued by looking for projects with similar houses from the sixties and the seventies. Within a project the aim was to renovate between four and five hundred homes, so that experience could be gained with a series-based approach. The initial intention was for several housing associations to jointly bring houses in a project in order to promote an snowball effect in the region. The plans that were made in the Slim & Snel projects were ultimately not scalable, partly due to the project based approach that the participants continued to keep. By focusing on innovation, integrality and scalability, the concepts also had to become affordable. The budgets that the housing associations had for the renovations were lower for each project, while the energy ambition went up. The idea also arose to realise a business case for the housing association by letting tenants pay housing costs (rent and energy costs) to the housing association. Unfortunately, legally and financially this was not yet possible within the existing frameworks.
‘De Stroomversnelling’ elaborated on the idea of realising affordable concepts by thinking in terms of the housing costs and the idea of realising a business case for housing associations. Also, much stronger efforts were made to arrive at scalable renovation concepts. The emphasis was on industrialisation and the realisation of building flows instead of working on a project basis. This was achieved by creating an even larger scale than was used for the ‘Slim & Snel’ projects. It is based on a deal in which agreements have been made for large numbers of houses in rapidly increasing steps; 1.000 in 2014, 11.000 in 2016 and 111.000 in 2020. This gave building parties the perspective with which they dared to invest in the development and design of an industrialised production process. By innovation the renovation was to be lowered in price and better suited to the wishes of the tenant. In order to realise a feasible business case for the housing association, the legislation has been adjusted so that from now on, in addition to the rent, they can also collect an energy performance fee for Zero-On-The-Meter houses. This cooperation agreement for ‘De Stroomversnelling’ was signed by four large construction companies and six housing associations. The intention was that during the duration of the agreement other housing associations could join in and the market would pick it up after the industrialisation phase and to realize 111.000 Zero-On-The-Meter dwellings.
Actions that contribute to energy neutral renovation concepts
In the analysis of the data, the improvements that Energy Leap tried to achieve were considered, as well as the obstacles they took away and the obstacles and opportunities they saw. A total of 78 possible actions were derived from this by the researcher for the development and large scale application of energy neutral renovation concepts, which have been subdivided into six main themes from the inductive analysis; supply and demand development, change amongst involved parties, support among residents, financing options, adjustment of institutional framework and transition management.
Based on the main theme of supply and demand development, actions have been formulated for the query of the housing association and the development of renovation concepts. By putting an open request to the market and by combining the demands of similar projects, housing associations can provoke the development of renovation concepts using the request specifications. By simultaneously working on demand and supply development and ensuring openness between the parties involved about possible solutions, both the demand can be tightened and the supply improved. Set up the design process in such a way that the renovation solution can be designed integrally as one system. Make the process a precondition for innovation and provide process support to help avoid existing thinking and working patterns and help with the collaboration. Design a renovation solution in which the house can be made energy neutral, but which is also an integral solution for the overall quality so the lifespan is extended and the house once again meets the current and future housing needs. To this end, expand the scope outside the dwelling. Work on a scalable renovation concept that can be applied for a large number of houses, but can also fulfil the wish for customisation and diversity. As housing associations expand the scale so that a construction building party can set up a new production process. As a building party begin by prototyping to be able to test the renovation solution and the production process. Then industrialise the production process and work from building flows. As a housing association, use an open market approach in the tender process to give new parties and concepts a chance. Buy a renovation concept as a product. Ensure competition and select both on hard and soft values. As a construction company, do market research and pay attention to marketing in order to meet the needs of the housing association and market the developed renovation concepts. As building party, offer the renovation concepts with a performance guarantee.
The main theme of change amongst involved parties relates to the role of the client and the contractor, the existing relationships with stakeholders, the cooperation and the change in the organisation. Actions aimed at the division of roles are: shift the design responsibility to the developing party, as a housing association transform to a purchasing company and service provider and as a construction company transform into a product company. Actions in the network of stakeholders are: involve new players for marketing and sales, involve (local) partners in the development, open up existing (supply) contracts and work on new services as an energy supplier. As a building company invest in your own innovation team. Cooperate integrally for the development of the concept and involve the entire chain. Cooperate on the basis of openness and equality. Changing roles means that new competencies are needed and policy and strategy must be adjusted.
Actions to create support among residents relate to customer oriented work, communication and the use of the house. To this end, develop the renovation concept based on the resident’s needs and give the resident the opportunity to choose for himself by offering the renovation in a demand oriented manner. Work from a strong brand that appeals to residents. Make joint communications to the residents as housing association and building company. Use a differentiated residents approach to connect with different types of residents and locations. Make the renovation and communication about it as concrete and understandable as possible for residents. Make sure the living expenses for the resident do not increase after the renovation. As a construction party give the resident long term guarantees on the performance of the dwelling. Put these guarantees in a contract, check the production and installation process and monitor the performance during use.
In the context of the main theme of financing options, actions are presented that relate to the financing by housing associations and the business case for the provider. Make sure the renovation becomes financially possible for the housing association by letting the money from the energy savings reach the housing association. For the financial assessment, consider the return over the lifespan instead of the initial investment. Ensure that there is a business case for the housing association at project level and ensure that financing can be obtained on the basis of the project returns. The business case of the construction party requires the pre-investment in the development of the renovation concept and setting up the production process. This expenditure is recovered by realising a large cost reduction on the realisation costs of the renovation and the creation of sufficient sales.
The main theme of the institutional framework adjustment includes actions relating to legislation, regulations, permits and procedures. For the business case of the housing association, an important action is the amendment to allow the energy performance fee. Also, the current ‘netting arrangement’ (salderingsregeling) limits the financial feasibility. These limitations can be solved by allowing the energy production be netted at the building complex level and to provide certainty about the future of the current netting arrangement. Additionally, let small scale sustainable energy supplies fall under the Services of General Economic Interest (SGEI) and allow for self-sufficiency,
because in the case of entirely sustainable production of energy in combination with storage, government regulated security of supply is not always necessary anymore. In the licensing process, the following actions can contribute to the use of renovation concepts: ensure uniform handling of permit applications, enable private quality assurance so that the renovation concept can be tested instead of a project, give a large scale exemption for (a part of) the environmental permit when standard extra measures are taken and provide room for experiments in the environmental permit.
Under the main theme of transition control are actions to boost the previous actions and to accelerate the transition. The following actions have been formulated for this approach: steer the transition from a process-oriented approach, work simultaneously to realise the required conditions, set up an intermediary for the link between different levels, stimulate initiatives and test them in practical experiments and use a flexible approach that allows room for adaptation based on new insights. A transition is about long-term changes. Set a perspective for this and steer on an almost impossibly high ambition level to bring about change. At the beginning of the transition, focus on innovators and work with a small number of parties that can actually carry out innovation projects. At the same time, keep the government, umbrella organisations and supervisory parties informed of the ideas for a smooth course of the scale-up. Gradually scale up to larger and more complex situations and issues. Make the front runners ambassadors and ensure that other parties can catch on after the ‘pilot phase’. Provide visibility and awareness and allow the government to facilitate in the entire process. Finally, link the energy neutral renovations to other social goals and use time of ‘crisis’ to make a really big turnaround.
Required conditions
To derive the necessary conditions, the relationship between the actions in relation to the transition is considered. To this end, a picture of the transition process has first been formed by comparing the lessons from the theoretical concepts on which Energy Leap is founded against the activities of Energy Leap and the derived actions. With this representation of the transition process, events in the transition process are schematically plotted against scale and time. This schematic picture shows that the transition takes place at multiple levels — project, network, sector and society level — and that change at all levels is necessary to bring about the transition. In addition, a distinction has been made in this scheme between creating innovation space for the development of innovation on the one hand and building up the new system for large scale application on the other.
The actions are placed in this image of the transition process. Eight sets of coherent actions have been formed by clustering these and making connections, from which the following conditions are derived:
the presence of an experimentation space within which a number of parties jointly start, where new parties can join in and within which the parties ca
aE Journal 2010/2011: aE connects Architecture and Engineering
No full textaE, Architectural Engineering teaches technology driven architectural design. It offers the possibility to graduate on a thesis design with room for technical fascinations. Since September 2008 aE has conducted graduation studios based on a set location that are extremely complex, they cover design decisions of regional scale as well as design decisions on the detail level, they let us think about the quality of the built environment in terms of urban spaces, the architecture of buildings and the impact decisions have on our environment in terms of sustainability. The aE studios have resulted in twenty-five thesis designs and there are many more to come. An overview of locations assignments and designs
Towards a Method of Participatory Planning in an Emerging Metropolitan Delta in the Context of Climate Change: The Case of Lower Paraní¡ Delta, Argentina
Get PDFThe Parana River is the third largest river in the American continent, after the Mississippi and the Amazon. Instead of flowing directly to the sea, it flows to the Rio de la Plata (located between Argentina and Uruguay) through a complex delta system. This delta is a large and heterogeneous territory that spreads over three provinces of Argentina and that is characterized by different dichotomies along its extension. On the one hand, the islands of the delta are young alluvial lands in constant transformation due to the processes of sedimentation, and are subjected to pulses of floods influenced by the Paraní¡ River streamflow, droughts, precipitations and strong southeastern winds coming from the Atlantic Ocean. Although these alluvial territories seem to be pristine, they have been moderately altered as a result of the development of economic activities. On the other hand, along the edges of the delta, we find the older territories of the mainland, created in the Pleistocene and less dynamic. Here is a network of cities of dissimilar sizes, that establishes the wealthiest corridor of the country. Conurbations such as Rosario (located in the province of San ta Fe) and the Metropolitan Area of Buenos Aires (located in the homonym province), exert different pressures over the territory, generating an increasing impact on the delta system. In other words, this delta shows a contrast between the wild and dynamic condition of the islands and the more stable but strongly urbanized edges. Nevertheless, this dichotomy is not the only one that can be found in the delta. On the contrary, there are other oppositions regarding economic, policy and social realms, expressed through a polarized, unsustainable and unplanned land use, which turns the area into a vulnerable place, given the uncertain context of climate change.
Although this delta can be considered an extreme and particular case, many of the conflicts that can be found in this area replicate in other deltas around the world. Urbanizing deltas are subjected to pressures related to urban growth and climate change, within a context of uncertainty and unpredictability. Those pressures interact at multiple scales and temporalities, affecting the components of the systems, as well as the relations between them and with the environment. This complexity reveals the need for the society (including governments, institutions, civil organizations, academia, etc.) to enhance the adaptability of the system of the delta, in order to cope with changes without losing their substantial characteristics.
This research is focused on the study of the complexity of self-organizing processes that emerge in metropolitan areas located in (or near) delta territories, in order to link climate adaptation with urban development from an actor-oriented perspective. This aim is motivated by understanding urbanizing deltas as complex adaptive systems formed by physical components, social actors and their mutual relations, which are in constant adjustment within the system and with the environment, in an atmosphere of uncertainty. In such a complex context, small changes can trigger qualitative impacts, that force the system to adapt in order to return to a new dynamic equilibrium. For example, in urbanizing deltas, extreme climatic events can cause tragic consequences when the context is not capable of adapting to that circumstances, generating effects at all scales. This vulnerability makes necessary to prepare to possible disruptive events though innovative planning methods towards increasing the system´s adaptive capacity. For that purpose, and adopting a bottom-up criterion, this research bases on the understanding of the self-organizing processes that emerge in urbanizing deltas to design and implement a methodology that can be applied at the local level, to generate an impact at other scales. The method designed in this thesis also includes the development of scenarios in order to think about possible future events and reflect on the necessary policy and actions to make the system respond to changes in a more adaptive way. The scenarios, as well as all the indicators analysed along the process, are developed through participatory workshops, after an analysis of the actor-network of the area, and also of the local, provincial and national regulations.
The method designed and implemented throughout this research is applied at the local level of the case study, and is flexible enough to be adapted for replicating it in other parts of the Argentinean Delta, in order to contribute to the increase of the systems´ adaptive capacity through the generation of initiatives at the local level that can generate an aggregate impact at higher levels
Thermal comfort and energy related occupancy behavior in Dutch residential dwellings
Get PDFResidential buildings account for a significant amount of the national energy consumption of all OECD countries and consequently the EU and the Netherlands. Therefore, the national targets for CO2 reduction should include provisions for a more energy efficient building stock for all EU member states.
National and European level policies the past decades have improved the quality of the building stock by setting stricter standards on the external envelope of newly made buildings, the efficiency of the mechanical and heating components, the renovation practices and by establishing an energy labelling system. Energy related occupancy behavior is a significant part, and relatively unchartered, of buildings’ energy consumption. This thesis tried to contribute to the understanding of the role of the occupant related to the energy consumption of residential buildings by means of simulations and experimental data obtained by an extensive measurement campaign.
The first part of this thesis was based on dynamic building simulations in combination with a Monte Carlo statistical analysis, which tried to shed light to the most influential parameters, including occupancy related ones, that affect the energy consumption and comfort (a factor that is believed to be integral to the energy related behavior of people in buildings). The reference building that was used for the simulations was the TU Delft Concept House that was built for the purposes of the European project SusLab NWE. The concept house was simulated as an A energy label (very efficient) and F label (very inefficient) dwelling and with three different heating systems.
The analysis revealed that if behavioral parameters are not taken into account, the most critical parameters affecting heating consumption are the window U value, window g value, and wall conductivity. When the uncertainty of these parameters increases, the impact of the wall conductivity on heating consumption increases considerably. The most important finding was that when behavioral parameters like thermostat use and ventilation flow rate are added to the analysis, they dwarf the importance of the building parameters in relation to the energy consumption. For the thermal comfort (the PMV index was used as the established model for measuring indoor thermal comfort) the most influential parameters were found to be metabolic activity and clothing, while the thermostat had a secondary impact.
The simulations were followed by an extensive measurement campaign where an in-situ, non-intrusive, wireless sensor system was installed in 32, social housing, residential dwellings in the area of Den Haag. This sensor system was transmitting quantitative data such as temperature, humidity, CO2 levels, and motion every five minutes for a period of six months (the heating period between November to April) and from every room of the 32 dwellings that participated in the campaign. Furthermore, subjective data were gathered during an initial inspection during the installation of the sensor system, concerning the building envelope, the heating and ventilation systems of the dwellings. More importantly though, subjective data were gathered related to the indoor comfort of the occupants with the use of an apparatus that was developed specifically for the SusLab project. This gimmick, named the comfort dial, allowed us to capture data such as the occupants’ comfort level in the PMV 7 point scale. In addition further comfort related data like the occupants’ clothing ensemble, actions related to thermal comfort, and their metabolic activity were captured with the use of a diary. The subjective data measurement session lasted for a week for each dwelling. These data were time coupled real time with the quantitative data that were gathered by the sensor system.
The data analysis focused on the two available indoor thermal comfort models, Fanger’s PMV index and the adaptive model. Concerning the PMV model the analysis showed that while the neutral temperatures are well predicted by the PMV method, the cold and warm sensations are not. It appears that tenants reported (on a statistically significant way) comfortable sensations while the PMV method does not predict such comfort. This indicates a certain level of psychological adaptation to occupant’s expectations. Additionally it was found that although clothing and metabolic activities were similar among tenants of houses with different thermal quality, the neutral temperature was different. Specifically in houses with a good energy rating, the neutral temperature was higher than in houses with a poor rating.
Concerning the adaptive model, which was developed as the answer to the discrepancies of Fanger’s model related to naturally ventilated buildings (the majority of the residential sector), data analysis showed that while indoor temperatures are within the adaptive model’s comfort bandwidth, occupants often reported comfort sensations other than neutral. In addition, when indoor temperatures were below the comfort bandwidth, tenants often reported that they felt ‘neutral’. The adaptive model could overestimate as well as underestimate the occupant’s adaptive capacity towards thermal comfort. Despite the significant outdoors temperature variation, the indoor temperature of the dwellings, as well as the clothing of the tenants, were largely constant. Certain actions towards thermal comfort such as ‘turning the thermostat up’ were taking place while tenants were reporting thermal sensation ‘neutral’ or ‘a bit warm’. This indicates that either there is an indiscrimination among the various thermal sensation levels or alliesthesia, a new concept introduced by the creators of the adaptive model, plays an increased role. Most importantly there was an uncertainty on whether the neutral sensation means at the same time comfortable sensation while many actions are happening out of habit and not in order to improve one’s thermal comfort. A chi² analysis showed that only six actions were correlated to thermal sensation in thermally poorly efficient dwellings, and six in thermally efficient dwellings.
Finally, the abundance of data collected during the measurement campaign led the last piece of research of this thesis to data mining and pattern recognition analysis. Since the introduction of computers, the way research is performed has changed significantly. Huge amounts of data can be gathered and handled by evermore faster computers; the analysis of these data a couple of decades ago would take years.
Sequential pattern mining reveals frequently occurring patterns from time-ordered input streams of data. A great deal of nature behaves in a periodic manner and these strong periodic elements of our environment have led people to adopt periodic behavior in many aspects of their lives such as the time they wake up in the morning, the daily working hours, the weekend days off, the weekly sports practice. These periodic interactions could extend in various aspects of our lives including the relationship of people with their home thermal environment. Repetitive behavioural actions in sensor rich environments, such as the dwellings of the measurement campaign, can be observed and categorized into patterns. These discoveries could form the basis of a model of tenant behaviour that could lead to a self-learning automation strategy or better occupancy data to be used for better predictions of building simulating software such as Energy+ or ESP-r and others.
The analysis revealed various patterns of behaviour; indicatively 59% of the dwellings during the morning hours (7-9 a.m.) were increasing their indoor temperature from 20 oC< T< 22 oC to T> 22oC or that the tenants of 56% of the dwellings were finding the temperature 20 oC< T< 22 oC to be a bit cool and even for temperatures above 22 oC they were having a warm shower leading to the suspicion that a warm shower is a routine action not related to thermal comfort.
Such pattern recognition algorithms can be more effective in the era of mobile internet, which allows the capturing of huge amounts of data. Increased computational power can analyse these data and define useful patterns of behaviour that could be tailor made for each dwelling, for each room of a dwelling, even for each individual of a dwelling. The occupants could then have an overview of their most common behavioural patterns, see which ones are energy consuming, which ones are related to comfort and which are redundant, and therefore, could be discarded leading to energy savings. In any case the balance between indoor comfort and energy consumption will be the final factor that would lead the occupant to decide on a customised model of his indoor environment. The general conclusion of this thesis is that the effect of energy related occupancy behaviour on the energy consumption of dwellings should not be statistically defined for large groups of population. There are so many different types of people inhabiting so many different types of dwellings that embarking in such a task would be a considerable waste of time and resources.
The future in understanding the energy related occupancy behaviour, and therefore using it towards a more sustainable built environment, lies in the advances of sensor technology, big data gathering, and machine learning. Technology will enable us to move from big population models to tailor made solutions designed for each individual occupant
Activerende Gevels: Naar gedrag beïnvloedende gebouwen
Get PDFAs a result of the large amounts of CO2 emissions the built environment produces, it contributes immensely to climate change. Within the strategies developed to reduce anthropogenic CO2 emissions, getting buildings to an energy-neutral level is one of the main priorities. The blueprint for this altered energy-efficient building now seems to be ready: the heavily insulated outer shells of buildings have decreased the demand for energy and the necessary coolness and warmth are induced using low-temperature systems.
Whether these changes are enough remains to be seen.
The actual, measured energy efficiency of these environmentally friendly buildings turns out to be lower than their theoretical efficiency; they use more energy than was expected up front. This difference can partly be attributed to the increased complexity of and sensitivity to improper use of these buildings. Users simply do not understand them well enough. Improper handling then turns into energy loss. Rebound effects also play a role in the lower levels of energy saving. The rebound effect states that as a result of higher efficiency, energy will relatively be cheaper. Lower energy bills will lead to a more increased use of warming and cooling, or to extra activities — whether or not polluting — outside the building.
The rebound effects make clear that environmentally friendly buildings do not automatically make their users less polluting; the energy efficiency of the building does not change people’s behaviour. One of the results of a survey that was conducted among 414 employees in five, energy efficient, and five more older, and less energy efficient office buildings in The Netherlands subscribes this. The environmental self-identity - which is regarded as the extent to which people perceive themselves to be a person whose actions are environmentally friendly — hardly differs from the office building users in both types of buildings (M = 4.977, SE = .069 vs. M = 5.052, SE = .075).
In order to reduce the rebound effects behaviour has to become more environmentally friendly. Changing behaviour sustainably is hard — because behaviour is based on routines - but it is not impossible.
Behaviour is influenced by values that are stable, transsituational and fairly abstract. When the contextual situation changes, these values and the (habitual) behaviour inherent to that specific situation can be re-evaluated. This implicates that in buildings, new contexts should be created: building should change in a more drastic and radical way than the evolutionary improvements made so far. Besides their energy efficiency the new energy efficient building differs little from their energy consuming predecessors.
The behaviour can also be changed by strengthen the environmental self-identity of people. Identity is the label with which somebody describes himself and it has a somewhat more flexible character than values have. For example, past behaviour is important for formulating one’s self-identity. It is seen as a cue to future behaviour. When somebody has shown environmentally friendly behaviour in the past, he is more likely to behave so in the future.
Changes in the context and ways to strengthen the environmental self-identity match the philosophy of among others Albert Borgmann who states that comfort, and the energy needed for it, will be more valuable when a user is more actively engaged in creating it. By being actively involved in sustainably creating an as ‘comfortable’ perceived indoor climate, people would feel they are behaving environmentally friendly, and having an environmental self-identity. Further, users would get the idea that they could act as a co-designer of that climate, as a result of which they would be more forgiving to it as well.
The increased environmental awareness resulting from this would then be the societal gain of a building that seduces its users to a more active involvement in creating the indoor climate. But why would users want to be seduced? In part, this could be attributed to the wish to control one’s living environment. Humans are comfort-seeking beings and when faced with discomfort, will find ways to remove that discomfort. Further, the ‘Theory of Planned Behaviour’ states that before behaviour is being performed, one will evaluate what that behaviour will bring as a return. In other words: will the behaviour lead to a positive or negative evaluation? It is obvious that the desired outcome is related to the professed values. So to be attractive to a diverse public, an activating building should appeal to different values.
Improving or sparing the environment alone is not enough however. Saving energy, having financial advantages, having greater control and an improved image can also play a role when choosing the systems, and the thereof arising behaviour.
This led to the following research question:
What effects does a façade system that activates its users have on their perception of thermal comfort, their satisfaction with the indoor climate, the use of energy and their environmental awareness?
Using an on the basis of this question designed activating, flexible, and adaptive façade (AfaF), a new context will be created in a test situation. Starting point is that however radical the facade to this end has to be, at the same time, one must be able to use it in an almost intuitive manner. In this way, the chances of making mistakes while using it will be minimized, and the chances to an actual and intensive use will be increased. When designing and materializing AfaF, the association with clothing is made. Just as when using clothes, extra layers of cloth are applied or removed when the situation inside or outside calls for it.
To test whether users actually see through this association, but also whether or not the increased control leads to an increased perception of thermal comfort and satisfaction with the indoor climate, a test pavilion was created. The herein assembled AfaF consisted of four layers: a water and wind proof layer, two insulating layers, and a sun-shielding layer with a low emission coefficient. One hundred and eighty one students and employees of the Hogeschool van Amsterdam, University of Applied Sciences (HvA) have participated in the tests; some of them were allowed to operate the AfaF, others were not.
The test results show that the test subjects with control over the AfaF saw it as an effective device to control the indoor climate. Next to effectiveness, one of the starting points in designing the AfaF was that it could be controlled intuitively. The time it cost the test subjects to manoeuvre the façade into the right configuration was thereby taken as a criterion. In the test unit with control over the AfaF, at the start of the test, the AfaF was purposely suspended in the wrong away, considering the outside conditions. The test subjects were then asked to re-configure the AfaF. On average, it cost them less than 5 seconds, which is lower than the ‘norm’. Furthermore, they strongly perceived the indoor climate they created to be a personal achievement.
Having control, however, seems to play out less strongly in experiencing comfort and satisfaction with the indoor climate. Only operating the AfaF a second time had a significant influence on the contentment with the indoor climate (F(1.85) = 8.168; p < .05; ƒž2 = .088). This contradicts other research that shows that control increases satisfaction. When prevailing temperatures are related to the perception of comfort and satisfaction with the indoor climate, however, both comfort and contentment turn out to score higher than was to be expected. Of the test subjects having control over the AfaF, 17% thought it was either too warm or too cold — which was lower than the test subjects without control scored (19.9%). The average perception of comfort in the test unit with control was slightly more positive than that in the test unit without control (M = 1.7; M = 1.8). Remarkable, however, is the low percentage of test subjects with control that were dissatisfied: 10.6%. And that even though the test pavilion did not have a conditioned indoor climate, and the indoor climate fluctuated with outside conditions that were rather cold. The use of a heater and a lamp, which were lined up in the test units, also shows that having control can have a positive influence on energy use. A significant relation was found between the re-operation of the AfaF and the turning off of the lamp (B = 1.590, SE = .512, p < .05, Exp (B) 4.904; R2 = .08). Further, the percentage of test subjects that turned on the stove in the unit with control was lower than the percentage of test subjects turning on the stove in the unit without control, respectively 25 to 34.7%. During these tests, the unit with control had a slightly less favourable climate then the unit without control. In 9 out of the 12 cases in which the heater was turned on, all options of using the AfaG to influence the indoor climate were exhausted. This form of energy saving can be regarded as ‘psychological’ energy saving — it feels more comfortable indoors than the temperatures actually justify. Using adaptive façades can, however, also lead to real energy saving. To determine how much can be saved, the software program VABI-elements was used to simulate a educational unit with the same dimensions and the same composition of the façade as the actual, physical test pavilion at the HvA. In the tests, cloths with varying thermal resistance, different masses and different emission coefficients were alternated. Starting from the layers with varying thermal resistance (wherein layers of Rc’s of 0.5; 1.5; 2.5; 3.5; 4.5; 6, and 8m2K/W were simulated with), a gain of 16.88% can be made when compared with a static façade with an RC of 8 m2K/W. To accomplish this, the user has to perform four acts only on a yearly basis: he must re-configure the façade cloths four times. When more acts are accepted, energy savings can go up to 20%. When the mass is made adaptive as well, 25% less energy is needed to realise a B-class indoor climate.
Further to these savings for the user — which will be regarded as an important motivation to start operating the façade - a broader societal goal was at the basis of the development of AfaF.
By operating the façade, users must get the idea that they are acting environmentally friendly, and this feeling must lead to a more environmentally friendly attitude. Not using the heater as much, and turning off the lamp in the unit with control over the AfaF points out that having control encourages environmentally friendly behaviour. To examine whether or not this behaviour would also extend to outside the building, the test subjects were asked to choose from two types of products: cheap, non-environmentally friendly products or 10% more expensive, but environmentally friendly products. Significant correlations were found between the environmental self-identity and the choice for environmentally friendly products with both students and non-students, the relationship between having control, and the chosen products was not found.
Having control has had a big influence on choosing a real reward, however. The goal for this last test was that ticking the box for, and thus accepting ‘a loss’ of 10% by choosing an environmentally friendly product, was rather noncommittal. The test subjects did not really have to pay for the products, after all. So, a month after the tests took place, a thank-you note was sent to all participants. Those that partook in the survey to discover the difference in perceived comfort, contentment with the indoor climate and the environmentally oriented self-identity of users of sustainable, and of older, less sustainable office buildings, received this e-mail as well. It stated that among all participants, four vouchers would be raffled. They were asked to make clear for what reward they would want to be considered: a Mediamarkt gift voucher, a travel voucher, a fair-trade basket, or an Oxfam Novib voucher.
Of all students, 87.4% chose a hedonistic reward — the Mediamarkt gift voucher, and the travel voucher. For students, €50 is a lot of money and their choice fits within the low cost theory that states that as soon as costs are perceived to be too high, sustainable behaviour will be abandoned. The difference between having control and not having control while choosing their reward was therefore scarcely found.
With non-students, however, significant differences were found between test subjects with and without control. The average amount of hedonistic vouchers chosen by nonstudents that were tested in the unit with control over the AfaF was considerably lower (16.7%) than the amount chosen by non-students in the unit without control (52.7%).
When the results are compared with those of HvA employees that did not participate in the tests, but did participate in the survey, it shows that operating the AfaF can have a positive influence on environmentally friendly behaviour. Of the HvA employees that were questioned, 65% chose a hedonistic Mediamarkt voucher and that is more than the non-students that had control in the test unit.
Thus, this research has determined and identified some forms of gains that could lead to the use of AfaF. To be able to define these gains as radical, however, the principles behind the activating, flexible and adaptive façade, the AfaF, eventually need to be embraced as well, and this can hardly be measured. What can be determined, however, is whether or not there is enough architectural leeway in the starting points of the AfaF to be able to give it architectural expression. Only then will the AfaF be interesting for architects. To examine this, a workshop was organized for seven architects who work at different Dutch architectural firms, and were asked to design an AfaF with an architectural character. The results show a large variety in adaptive and flexible possibilities of the façade, both in ways in which the users can be activated and in architectural expression that can be traced back to a very specific signature.
This research showed that an activating façade can initiate environmentally friendlier behaviour, and can be the first step towards a genuine reform of the built environment
Form Follows Force: A theoretical framework for Structural Morphology, and Form-Finding research on shell structures
Get PDFThe springing up of freeform architecture and structures introduces many challenges to structural engineers. The main challenge is to generate structural forms with high structural efficiency subject to the architectural space constraints during the conceptual structural design process.
Structural Morphology is the study of the relation between form and force, which can be considered the guiding theory for this challenge. The relation between form and force is important for all types of structures during the entire structural design process. Thus, Structural Morphology has a wide range of related research subjects and multiple research approaches. Therefore, Structural Morphology has gained neither a clear definition nor a unified methodology.
In the present research, a theoretical framework for Structural Morphology has been proposed, that provides an effective solution to the challenge mentioned above. To enrich the proposed framework of Structural Morphology, systematic Form-Finding research on shell structures is conducted. Shell structures, the structural efficiency of which depends strongly on their 3D shape, have particular problems regarding the relationship between form and force. To obtain a structurally efficient shell, the form should follow the flow of forces, and a process of Form-Finding can achieve this. In this thesis, Form-Finding of shells indicates a process of generating the equilibrium structural forms of hanging, tent or pneumatic physical models.
In Chapters 2 and 3, a theoretical framework for Structural Morphology is established.
Structural systems are divided into two categories based on their responses under the loads: ‘Force-Active’ and ‘Force-Passive’. A ‘Force-Active’ structural system can significantly and actively adjust its shape due to the loads, while a ‘Force-Passive’ system cannot. A generic conceptual model of the numerical analysis process of structural systems is presented, which is suitable to both categories of structural systems. This conceptual model includes three parts: (1) the initial system described by five categories of parameters: geometry, material distribution, material properties, boundary conditions and forces; (2) the setup of equations and calculation methods to handle the above parameters; and (3) the structural performance described by two categories of parameters: the structural form and its mechanical behaviour (Chapter 2).
A conceptual model of Structural Morphology is proposed by adding further requirements of the structural form or the mechanical behaviour and an optimisation process into the above conceptual model of the numerical analysis process of structural systems. Then, a corresponding conceptual formula of Structural Morphology is concluded. Thus, a theoretical framework of Structural Morphology is established. Subsequently, its feasibility is validated by a comprehensive discussion of the two main aspects of Structural Morphology, including ‘Form-Finding’ and ‘Structural Optimisation’. In this research, Form- Finding relates to Force-Active structural systems, which means the generation of multiple equilibrium shapes subject to architectural space constraints. Structural Optimisation relates to Force-Passive structural systems, which indicates the adjustment of relevant parameters of the initial structural system with the aim of improving its mechanical behaviour. The methodology of both aspects is presented. Research achievements completed by the author’s research groups from Harbin Institute of Technology (HIT) and Delft University of Technology (TU Delft) are presented to validate the feasibility. These achievements cover the research on Form-Finding of cable-nets and membrane structures, and on the Structural Optimisation of shells and gridshells (Chapter 3).
In Chapters 4 to 7, the proposed theoretical framework for Structural Morphology is enriched by systemic Form-Finding research on shell structures.
To study the form of shell structures, the curvature analysis of the surface is displayed. To study the mechanical behaviour of shell structures during the conceptual structural design process, an assessment strategy based on its linear static behaviour and buckling behaviour under two different load cases is proposed. To comprehensively study the linear static behaviour of a shell structure where bending moments may or may not be dominant in this shell, the membrane over the total stress ratios and strain-energy ratio are introduced (Chapter 4).
The Vector Form Intrinsic Finite Element (VFIFE) method is a recently developed numerical analysis method. At the beginning of this research, few studies on the Form-Finding of shell structures using the VFIFE method were found in the literature. The VFIFE method is applied to generate equilibrium shapes of Force-Active structural systems and thus the structural geometries of shells. A MATLAB script and a plug-in in the Rhino-Grasshopper platform are developed (Chapter 5).
Form-Control of Force-Active structural systems aims to generate form-found structural forms subject to the required architectural space constraints. Two Form-Control strategies are developed by combining two simple optimisation algorithms (the Newton-Raphson method and the inverse iteration method) with the VFIFE method. These strategies can help designers determine the structurally efficient forms more easily and more efficiently than some relatively complicated and time-consuming optimisation algorithms (Chapter 6).
Based on the proposed theoretical framework of Structural Morphology, multiple structural forms of form-found shell structures are obtained by adjusting the five categories of parameters of the initial structural systems. This work can efficiently and effectively provide multiple structural forms with reasonable mechanical behaviour for designers from the perspective of structural engineers (Chapter 7).
In Chapters 8 and 9, the specific influence of curved supports on the structural forms and the mechanical behaviour of these shells is studied. Intuitively and qualitatively, designers may be able to select the correct shapes for the supports of shells. However, there was a need to quantify the consequences of designing particular shell supports. In this work, form-found shells with slightly different support shapes are analysed numerically and experimentally.
Four hexagonal form-found shells generated from hanging models with different support shapes but with the same target point are generated. The following four support shapes are considered: straight supports, outwardcurved supports, inward-curved supports and strongly inward-curved supports. From the numerical comparison, slight changes of the support shapes have a relatively small influence on the equilibrium structural forms but have a considerable influence on the mechanical behaviour of these form-found shells. It is concluded that we can improve structural efficiency by slightly curving the supports during the Form-Finding process, which would not significantly change the architect’s design scheme (Chapter 8).
In the experimental research, three scaled plastic shell models (with straight supports, outward-curved supports, and inward-curved supports) are tested, and the shadow Moirí© method is used in the observation of the deformation of the shells. Form these tests, the influence of the support shapes on form-found shells is studied visually by these obtained Moirí© patterns, which represent the buckling modes of these shell models influenced by the curvature distribution near the supports as well as thickness distribution (Chapter 9).
There are still issues that need to be solved in future research. For instance, the theoretical framework for Structural Morphology needs to be enriched with Structural Optimisation work, more complicated design constraints need to be considered in the Form-Finding process of shell structures (for example, the stress level or distribution in the shell), and more influence factors of the form-found shells need to be researched (for example, the number or length of the supports, and edge beams)
integrated urban planning: directions, resources and territories
Get PDFThe purpose of this book is to present ongoing research from the universities involved in the project Creating the Network of Knowledge Labs for Sustainable and Resilient Environments (KLABS). The papers published in this book show that the recent and current research in those institutions focuses on the directions of development of IUP, the processes that support sustainable use of natural resources and their application in the Western Balkan and some other European countries. Each essay aims to provide an overview of key aspects of the research topic.
Over the first two decades of the 21st century, some significant changes have been taking place in the natural environment (climate change, loss of biodiversity), societies (increased migrations, population growth and aging, increasing gap between poor and rich), and economy (globalisation, financial crash, digital revolution and increasing automatisation), new directions are emerging for sustainable human development with the aim to overcome those problems. Some novel research directions are reviewed by Maura Benagiamo whose chapter provides an overview of the critiques of the resilience paradigm, the recurrent concept of de-growth, as well as of the political ecology approaches towards the potential resolutions related to the problems of implementing IUP. When a significant and not yet fully functional political restructuring takes place, as in the case of Republic of Srpska within Bosnia and Herzegovina, a certain situation arises: the barriers to implementing IUP and the directions for their removal by improving the IUP methodology, the related professional education, and the training, as well as strengthening of the institutional and socioeconomic capacities, are analysed by Brankica Milojevic. Following an outline of the concept of a new urban governance model required for IUP and the application of IUP as an instrument for creating sustainable public policies on urban development, the chapter by Marija Maruna, Danijela Milovanovic Rodic, and Ratka Colic provides information on the implementation of the IUP principles in the teaching of master students at the University of Belgrade.
The key issues in the use of natural resources in order to plan efficient and productive cities are explored by investigating the relationship between the concepts of resource efficiency and resilience in the chapter by Antonio Girardi. One of the aspects of resource efficiency, that of waste reduction, reuse, and recycling in Serbia, is analysed in the chapter by Marina NenkoviÇ-RizniÇ and demonstrated by presenting innovative approaches to waste management in the municipality of New Belgrade. As natural resources and the built environment made of those resources need to be protected from natural disasters such as flooding, two chapters by Žana TopaloviÇ and Äurica MarkoviÇ provide an overview of integrated flood management approaches and flood risk management procedures, policies, and practice.
The final group of chapters focuses on how territories are affected by economic, political, and social pressures and what governance instruments should be improved to address them. The negative impacts on cities of neo-liberal economy through market-driven global investments are investigated by Dan Narita who proposes ecologically driven urban development approaches that increase the resilience of natural and built environments. The pressure of informal city growth and how to resolve this challenge through responsive master planning are key issues explored in the chapter by Biserka Mitrovic, Jelena Maric, and Tamara Vukovic. Participatory approaches instead of state-led land use planning are proposed as a way forward for IUP of urban-rural communities in the chapter by Martin Broz, who discusses how they can support a balanced agricultural production and strengthen relationships between urban and rural areas.
The above essays provide evidence of the research on some of the key problems that must be solved when applying IUP. The need for improving governance systems and instruments that will enable the application of IUP principles to emerge as a cross-sectional theme. The researchers’ engagement in real-life case studies demonstrates that their proposals for improvements in policies, practice, and professional education are founded on valuable insights. We believe that the presented research outputs will be an important source of knowledge for the students at various new MSc courses that focus on sustainable and resilient built environments in Western Balkan countries, as well as for policymakers, urban planners, and other researchers in this field
aE Journal 2013/2014: The Future is Architectural Engineering!
No full textIn the early 80s, I graduated at the department lead by Professor Jaap Bakema, the man that coined the term ‘van stoel tot stad’ (from chair to city). It offered me insights into the gradations of scale and different disciplines that characterize the building industry. These different levels of scale and disciplines are also at the foundation of my two-fold experience with building practice of the past decennia: that of architect and that of booster of architectural policy. This experience proves useful now: since the beginning of the 21st century, a permanent shift of the role and position of the architect within building practice becomes apparent. Those who want to connect the culture of building with technological innovation must know how design and ingenuity are interconnected. The present is asking for new values. We must combine a strong dose of innovation with the urgency of renewing the building stock
Synergetic Urban Landscape Planning in Rotterdam: Liveable Low-Carbon Cities
No full textIn this PhD research, the major environmental challenges of our time, such as climate change, sustainable energy transition and scarcity of resources, are approached from a spatial, landscape-architectural perspective. The goal is to accelerate the transition to liveable, low carbon cities. The focus of the research is at the local scale and attempts to turn challenges into opportunities for a better quality of life and living environment. Since 1857, when Frederick Law Olmsted combined the construction of two large drinking water reservoirs for the city of New York with the design of a beautiful park, these types of assignments are part of a landscape architect's job. At that time, the issue was to solve the problem of drinking water while now we are concerned about solving the combination of very diverse and different flows. This renders the assignment more complex but certainly no less landscape architectonic.
As part of this research, many functions, flows, areas and actors in the urban landscape system of Rotterdam have been studied. This research focuses on the development, design and testing of new approaches to strengthen existing urban qualities and to tackle problems in such a way that positive effects for other functions (synergies) arise at the same time in order to improve the quality of life in cities.
The themes researched are:
1 Water and climate change: storm water challenges and water in the city (such as flooding) and how these might provide opportunities for a better environment
2 Energy transition: exchange of residual flows of heat in order to achieve a more sustainable energy supply.
3 Urban agriculture and nutrients: urban waste flows of phosphorus and urban agriculture as related to liveability. All these themes could also be investigated per sector and that is often what is done, however this research looks at their inter-connectedness and the possibility to promote synergies.
For this, it is important to know what kind of synergies can be achieved and for whom. As a result, planning for synergies in a structured way is possible. Landscape architectural, urban ecological and governance theories are used to extract building blocks and to set up a so-called Synergetic Urban Landscape Planning (SULP) approach. This is an integrated approach that allows us to explore, imagine and plan synergies so as to accelerate the transition to a liveable, low carbon city. During the research process, SULP has continuously been reinforced by incorporating the results of the separate studies on water, climate, energy, urban agriculture and nutrients. Synergetic urban landscape planning forms the bridge between CO2 and liveability goals on the one hand, and principles for sustainable urban development on the other. This research and this approach was fed with, and strengthened by, the results of separate studies on water, climate, energy, urban agriculture and nutrients.
To test this approach, SULP building blocks were used in the inner city of Rotterdam. Possible densification and greening strategies were built together with stakeholders. This has resulted in a plan for the various components such as water and energy, which greatly improved multiple liveability aspects of the inner city and reduced CO2 emissions per capita. These results were also used to further develop the SULP approach such as the development of the ‘Smart City Planner’, based on the principles and indicators of sustainable cities, an assessment tool linked to Geographical Information Systems (GIS). This tool can be used to assess the sustainability performance of neighborhoods as well as to plan for synergies.
This research contributes to sustainable urban development and emphasizes the role of landscape architecture in this regard as it provides synergies within urban metabolism (flows in the city). It also leads to closer cooperation with other disciplines. New approaches have been developed through SULP some of which have already been successfully applied, for example the ‘Rotterdam Energy Approach and Planning’ (REAP) as well as the ‘Smart City Planner’. Approaches that accelerate the transition to a liveable, low carbon city
Trajectories of neighborhood change
Get PDFNeighborhoods represent a scale at which inequalities are reflected in the unequal spatial distribution of ethnic and income groups across urban space. In many cities, the rich reside in high-quality neighborhoods in favorable locations while the poor are concentrated in disadvantaged areas (Hulchanski, 2010; Van Eijk, 2010). However, neighborhoods are not static entities and spatial patterns of socioeconomic and ethnic inequality shift over time as a result of processes of neighborhood change. Neighborhoods can develop in different ways: (1) they can gentrify which is characterized by rising house prices and the replacement of lower income groups by higher income groups (Hochstenbach & Van Gent, 2015; Newman & Wyly, 2006; Slater, 2006); (2) neighborhoods can decline which is indicated by physical deterioration and declining house prices and the succession of higher income groups by lower income groups (Grigsby et al., 1987; Prak & Priemus, 1986; Van Beckhoven et al., 2009); (3) neighborhoods can remain stable in their population composition and/or overall status for longer periods of time (Meen et al., 2013; Tunstall, 2016).
There are two empirical gaps in the literature on neighborhood change that this dissertation addresses. First, there has been a lack of longitudinal studies. Many studies on neighborhood change take on a relatively short-term perspective and reduce change to the difference between two points in time. While the literature has been dominated by case-studies on gentrification or decline, fuelling the assumption that gentrification and decline are widespread processes that quickly transform neighborhoods and cities, a growing body of research suggests that neighborhoods are rather ‘slothful’ and that neighborhood change takes time to take effect (Tunstall, 2016; Meen et al., 2013). Overall, we have little insight into the extent to which gentrification and decline are exceptional cases, in addition to, the prevalence and rate of change across all neighborhoods over time (cf. Tunstall, 2016).
Second, residential mobility is often seen as the most important driver of neighborhood change. However, residential mobility is shaped by structural factors such as the housing stock, local housing markets, and government policy (Meen et al., 2013; Nygaard & Meen, 2011). Moreover, researchers have argued that residential mobility should be understood in relation to demographic and in-situ change, which can also play an important role in processes of neighborhood change (Bailey, 2012; Finney & Simpson, 2009; Teernstra, 2014). The relative impact of the housing stock and different population dynamics on neighborhood change has however received little attention in the literature to date.
This dissertation contributes to the literature on longitudinal neighborhood change, both theoretically and methodologically. Theoretically, it provides insight into diverging pathways of neighborhood change over time, illustrating how different mechanisms interact to shape the urban geography along socioeconomic and ethnic lines. The path-dependent role of the housing stock is analyzed, in addition to the extent to which changes to the housing stock as a result of urban restructuring affect residential mobility and neighborhood change. Moreover, this dissertation investigates patterns of ethnic segregation over time and explores the relative impact of residential mobility and demographic change. Methodologically, this dissertation explores innovative methods for the analysis of neighborhood trajectories, broadening the scope of statistical methods for the field of neighborhood change research.
This dissertation uses individual-level administrative data from the System of Social statistical Datasets (SSD) provided by Statistics Netherlands. The SSD contains longitudinal geocoded data on the full Dutch population, as well as information on the built environment. As such, the SSD allows for the analysis of the relationship between the housing stock and population change in processes of neighborhood change. Neighborhoods are operationalized using 500 by 500 meter grids, which are the most consistent low spatial scale over time. Three out of four chapters focused on the 1999 to 2013 time period, while chapter 3 covered the 1971 to 2013 period. This dissertation employed innovative methodologies to analyze trajectories of neighborhood change over time. Chapter 3 presents a combination of sequence analysis and a tree-structured discrepancy analysis that allows for the visualization of neighborhood pathways and its relation to their contexts. Chapter 5 uses a Latent Class Growth Model (LCGM) to categorize neighborhoods based on similarities in the timing and pace of change over time. Both methodologies have proven to be valuable tools for the identification of diverging neighborhood pathways over time.
Summary of chapters
This dissertation is comprised of five separate, but related papers. Chapter 2 presents a literature review of theories and studies on neighborhood decline. Chapters 3 to 6 are empirical research papers that have their own theoretical framework, empirical analyzes, results and discussion section. All papers have either been published in peer-reviewed journals or are currently under review. The content of chapters 2 to 6 is summarized below. The Global Financial Crisis and neighborhood decline
Chapter 2 presents an overview of the literature and theories on the spatial consequences of the Global Financial Crisis (GFC). The impact of the GFC and the economic recession that followed is unevenly distributed between households and individuals, with low-income and vulnerable households being affected the most. As such, it can be expected that the consequences of the GFC are most pronounced in disadvantaged neighborhoods. While many studies have investigated the effects of the GFC on the economy and/or housing markets, only a few studies have focused on the unequal geographical impacts of the GFC (Batson & Monnat, 2015; Foster & Kleit, 2015). This chapter bridges two streams of literature by formulating ten ways in which the GFC might accelerate processes of neighborhood decline. The main goal of this chapter is to further the intellectual debate on neighborhood decline and to call for more longitudinal research on the ways in which the GFC has affected neighborhood trajectories and spatial patterns of increasing inequality.
The path-dependency of low-income neighborhoods
Chapter 3 presents an innovative longitudinal approach to analyzing neighborhood change and investigates the trajectories of low-income neighborhoods in the 31 largest cities in the Netherlands over the 1971 to 2013 period. Many studies on neighborhood change are limited by relatively short-term perspectives, and/or a focus on specific case-studies of gentrification or decline (e.g. Bailey, 2012; Jivraj, 2013; Hochstenbach & Van Gent, 2015). As such, it is unclear to what extent neighborhoods with similar characteristics experience the same process of change over time — or to what extent gentrification or decline are the exception to the rule. Using sequence analysis and a tree-structured discrepancy analysis, this chapter contributes to the literature by analyzing how housing stock characteristics shape neighborhood trajectories over longer periods of time. The results show that neighborhoods exhibit a high degree of path-dependency. Neighborhoods with high shares of social housing in 1971 display a pattern of increased poverty concentration and neighborhood decline over time. By way of contrast, increases in the share of owner-occupied housing contribute to more upward neighborhood trajectories.
The effects of physical restructuring on neighborhoods
Chapter 4 analyzes the effects of urban restructuring programs on neighborhood change in the 31 largest Dutch cities. Researchers have been critical about the effectiveness of urban restructuring in actually achieving upgrading neighborhoods (e.g. Lawless, 2011; Permentier et al., 2013; Tunstall, 2016; Wilson, 2013). However, many studies have been faced with methodological limitations with respect to measuring urban restructuring, spatial scale, and time periods. Chapter 4 overcomes these limitations by focusing on the effects demolition and new construction on a low spatial scale over a 15- year period. Using propensity score matching, this chapter finds a positive causal effect of demolition and new construction on neighborhood upgrading. The results indicate that large-scale demolition and new construction leads to socioeconomic upgrading of deprived neighborhoods as a result of attracting and maintaining middle- and high-income households. Urban restructuring appears to have negative spillover effects in terms of an increased share of low-income households in other neighborhoods.
Trajectories of ethnic neighborhood change
Chapter 5 focuses on trajectories of ethnic neighborhood change in the four largest Dutch cities, Amsterdam, Rotterdam, The Hague and Utrecht, between 1999 and 2013. As the share of ethnic minorities continues to grow in many cities, this raises concerns about increasing levels of ethnic segregation. The literature has been divided on the methods for analyzing ethnic segregation over time and many researchers have relied on single-number indices or typologies based on arbitrary thresholds (e.g. Duncan & Duncan, 1955; Johnston et al., 2010; Massey & Denton, 1993; Peach, 1996; Poulsen et al., 2001). Chapter 5 presents an innovative alternative for the identification of trends in the ethnic population composition over time. Using LCGMs, this chapter finds that neighborhoods show relative stability in the ethnic population composition over time, despite a substantial growth in the ethnic population. Although ethnic minorities are increasingly moving away from concentration neighborhoods, processes of natural growth play an important role in maintaining levels of ethnic segregation.
Intergenerational continuity of ethnic segregation
Chapter 6 investigates persistent patterns of ethnic segregation over the course of generations. In the literature, it is assumed that ethnic segregation will decrease over the course of generations as later generations will be more socially and economically integrated in society (e.g. Massey, 1985). This assumption is reflected in the official Dutch definition of ethnicity that classifies individuals whose parents are born in the Netherlands, but with one or more immigrant grandparents, as native Dutch. The use of this definition has important empirical consequences and influences conclusions about ethnic neighborhood change. Focusing on the residential patterns of third generation parental home-leavers in the 31 largest Dutch cities between 1999 and 2013, this chapter illustrates that third generation ethnic minorities continue to be overrepresented in ethnic concentration neighborhoods. The intergenerational continuity of socioeconomic disadvantage among ethnic minorities plays an important role in persistent ethnic segregation over time.
Findings and conclusions
The findings of this dissertation contribute to the field of neighborhood change research in four ways. First, this dissertation has demonstrated that neighborhoods tend to be relatively stable in their socioeconomic and ethnic status over time and that neighborhood change takes several decades to take effect. Second, this dissertation underlines the determining role of the housing stock in processes of neighborhood change. Neighborhoods exhibit a high degree of path-dependency where the initial quality of the built environment is reinforced over time. Chapter 3 has illustrated that the share of social housing is an important determinant of future processes of neighborhood decline. Changes to the housing stock, however, have the ability to alter the trajectories of neighborhoods. Chapter 4 has shown that large-scale demolition and new construction as a result of urban restructuring programs has led to neighborhood upgrading by attracting and maintaining higher income groups. Third, this dissertation has illustrated how different population dynamics interact to maintain the status quo. Chapter 5 and 6 have identified persistent patterns of ethnic segregation over time as a result of socioeconomic disadvantage among ethnic minorities which leads to high residential mobility rates into ethnic concentration neighborhoods. Although residential mobility is often seen as the most important driver of neighborhood change, this dissertation adds to the growing literature on the role of demographic change. The effects of ethnic residential mobility out of concentration neighborhoods on ethnic segregation are mitigated by processes of natural growth. Fourth, this dissertation has explored innovative methods for the analysis of longitudinal patterns of neighborhood change. Sequence analysis in combination with a tree-structured discrepancy analysis allows for a detailed analysis of neighborhood trajectories and the relationship with their contexts. LCGMs enable the identification of diverging neighborhood patterns of change based on timing and pace.
Challenges and limitations
Despite the contributions to the literature, this dissertation is also faced with several limitations, three of which are highlighted below. First, this dissertation has analyzed patterns of neighborhood change, but has not directly focused on gentrification. While some view urban restructuring as a form of state-led gentrification (e.g. Uitermark & Bosker, 2014), this dissertation sees urban restructuring as fundamentally different from more natural processes of gentrification. The term gentrification has become widely used (and abused) for a wide variety of different and, sometimes unrelated, processes leading to neighborhood upgrading. Future research would benefit from clearly defining gentrification and for analyzing gentrification over longer periods of time. Currently, we have very little insight in the prevalence, rate, and extent of gentrification across neighborhoods and cities and it is unclear to what extent its effects are temporary or long-lasting.
Second, this dissertation has limited its focus on the four largest ethnic groups in the Netherlands. However, the spatial distribution of these four ethnic groups is likely to be related to the residential behavior and distribution of other ethnic groups in the Netherlands. Future research would benefit from comparing patterns of segregation across different ethnic groups and the ways they interact to shape the urban geography along ethnic lines.
Third, the innovative methods employed in this dissertation enable the analysis of patterns of neighborhood change, however, they are not without limitations. Both methods allow for the identification of groups of neighborhoods that follow similar trajectories over time. However, these methods are faced with a degree of uncertainty around the true number of groups. In addition, a tree-structured discrepancy analysis uses the most significant values of the predictor variables as cut-off points, however, it is unclear to what extent these values can be interpreted as threshold values in processes of neighborhood change. Overall, these limitations reflect the nature of the modelling process and underlines the need to string theoretical reasoning beneath the models.
Policy implications
This dissertation has underlined the relative stability of neighborhoods over time. Policy makers should keep in mind that neighborhood change takes time to take effect, often exceeding standard policy time periods. Large-scale changes to the housing stock in the context of urban restructuring programs have the ability to generate neighborhood change by stimulating selective residential mobility. However, the positive effects of urban restructuring are limited to the restructured neighborhood. Other neighborhoods appear to suffer from negative spillover effects, illustrated by an increase in the share of low-income households as a result of displacement.
The GFC has accelerated the shift towards the marketization of social housing. Some cities aim to stimulate gentrification through the sales of social housing which reduces the size and quality of the social housing stock. The spatial consequences of such policies are however unclear and may take time to take effect. Policy makers should be aware that reducing the size and quality of the social housing stock in large cities complicates the accessibility of cities for low-income groups and can have a major impact on the urban geography of cities and regions.
This dissertation has found persistent patterns of ethnic segregation which can be explained by intergenerational ethnic disadvantage. The question remains to what extent spatial patterns of ethnic disadvantage should be targeted by urban (re)development. As studies have shown that ethnic socioeconomic mobility tends to lead to more residential opportunities and spatial dispersal, it could be more beneficial to invest in education and labor market participation.
Last, this dissertation has illustrated that official definitions of ethnicity can influence empirical conclusions. Ethnic origin is based on the country of birth of the parents, however, this indicator ignores other aspects of ethnic origin. Later generations of ethnic minorities might still be characterized by other aspects of ethnic origin that play an important role in group inequalities. As society is becoming increasingly diverse, policy makers should be sensitive to ethnic differences and group inequalities that are not directly reflected in official statistics