In this article, we highlight some of our learnings from realised refurbishment projects on residents’ actions and motivations in the various ways they aerate their home. The aim of the projects is to contribute to global climate change mitigation goals by developing residential energy-reducing refurbishments that can be upscaled (Silvester et al., 2017). Our research has a design research perspective, which means that we enquire into the relationship between the residents and the user interfaces and building elements in their refurbished home. We draw these learnings from our involvement as observers and advisers in several recent zeroenergy refurbishment projects in social housing in the Netherlands. We will show that the residents’ actions are related to their trust in the user interfaces. Thistrust is in turn related to some of the values that the residents expect their home to address: support keeping healthy, facilitating their activities and lifestyle, andhaving systems that are easy to use and control (Guerra-Santin et al., 2017).@en

Existing residential housing has to become more sustainable to meet global CO2 reduction goals. Zero energy home refurbishment is one approach to achieve this. Rather than the currently common behaviour change approach, this study investigates residents’ experiences and practices with regard to their home environment. The study consists of interviews in 11 residents’ own homes. The residents live in homes in various levels of refurbishment, including zero energy. The study focuses particularly on ventilation. Ventilation is an issue that is understudied yet known to affect homes’ energy performance as well as residents’ comfort experience. The study reveals many issues with trust, understanding and unfavourable associations of ventilation systems. The study then presents a number of exemplary design directions that could address these issues. The implications are that practices should be studied more to reveal such issues, and that there is a need for better home systems design approaches.@en

Feedback systems with direct feedback have shown to be effective in stimulating households to change their energy consumption levels. This research is one of the first to explore the use of apps to influence household energy use. Compared to dedicated in-home displays, smartphone/tablet apps provide a low-cost and simple design solution for making energy feedback available. This research consisted of three studies conducted with different samples within a selection of households where a smart meter was installed as part of the smart meter implementation program in the Netherlands. First, for a period of 16 months, electricity and gas consumption levels were measured for a large sample of households (n = 519) divided into an application user group and a reference group. Second, questionnaires (n = 270) provided insight in how people used the applications and to what extent the applications increased households’ insight in their energy consumption and stimulated behavior changes. Third, interviews (n = 12) were held to obtain more in-depth insight. In the sample with measured energy consumption, we did not find a significant reduction in electricity and gas consumption during this research. Yet in the questionnaires, the application users reported more energy awareness and indicated to have made more investments and changes in their behavior than the reference group. Most app users started using the first app they found and did not explore the other options. The interview results indicate that, after an initial learning period, the app was used to monitor the electricity and gas consumption levels, rather than to lower them. In line with other research into feedback, the interview results suggest that the apps could be more effective with information that is more actionable and meaningful with respect to one’s own specific situation and goals for the household. Further exploration is recommended with respect to how the design of such apps can encourage a wide audience not only to monitor their consumption, but also guide them in taking action to change their consumption levels.@en

Charging electric vehicles from solar energy provides a sustainable means of transportation. This paper shows the design of solar powered e-bike charging station that provides AC, DC and contactless charging of e-bikes. The DC charger allows direct DC charging of the e-bike from the DC power of the photovoltaic panels (PV) without the need for an external AC charger adapter. In case of the contactless charger, the bike can be charged without the use of any cables providing maximum convenience to the user. Finally, the charging station has an integrated battery that allows for both grid-connected and off-grid operation@en

According to the IPCC Climate Change projections by 2050 temperatures in southern Spain will have increased noticeably during the summer. Housing-in its current form-will not be able to provide a suitable response to this new climate scenario, and will in turn prompt an increase in cooling energy consumption and a series of problems relating to health and comfort. The Design Builder simulation tool was used to quantify the impact of this future climate scenario on energy demand, as well as its effect under free-running conditions on indoor temperature. Different passive conditioning strategies were evaluated to establish their influence on the indoor comfort conditions. The case study examined a theoretical single-family residential unit model in order to establish guidelines for the pre-selection of the most suitable passive solutions. The results show that passive conditioning strategies analysed (envelope treatment, solar gain protection and night-time natural ventilation) reduce energy demand and indoor temperatures, thus increasing energy efficiency and improving indoor comfort conditions. Therefore, these passive conditioning strategies reduce the cooling energy consumption.

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Development of electric mobility and sustainable energy result in new technologies such as contactless electric vehicle charging and roadway energy harvesting methods, but also self-healing asphalt roads. By combining these technologies a new concept of Future Sustainable Roads for Electric Mobility is created and presented in the paper. This paper bridges the gap created by these unilateral technology developments using a multi-disciplinary approach including placing cautions when necessary and suggesting viable alternatives for optimal utilization of these energy transfer and conversion techniques. Through theoretical analysis, simulations, and tests on lab-scale experimental prototypes, the impact of our proposal is showcased. Thermal and loss models are developed for self-healing asphalt. Also, integration study of solar roads and contactless charging is performed. Applying the insight gained from the results, it is discussed how some challenges also pave a way towards interesting opportunities, for instance, infrastructure sharing for material use optimization and efficient mosaic integration. Finally, an economic viability case study is presented for a future Dutch highway with such newly emerging components.

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Thisresearchisfocused ona social housing renovation process. We as academics develop tools to supportthe stakeholders in collaboratingtowards resident acceptance and a zero-energy balance.This paper reports a preparatorystep in which we developed and evaluated visualisations. These serve to engage the stakeholders in collaboratively focusing on the residents' experience oftherenovation process. We evaluated the visualisations with residents, housing association professionals and building professionals. Academic learnings are that the visualisations evoke stakeholder reflections on the residents' experience of the processthat help us to later developtoolsfor the process.Stakeholderlearnings are: the visualisationshelped tenants reflect on their experience of the process, they helped housing association professionals reflect on their communication, and they helped building company professionals listen to residents. The visualisationsareabstract and general, limiting their usefulness throughout a renovation process, buttheyform a basis for the further development of tools.@en

We present a participatory process in the context of networked collaboration in the field of construction, and offer the concept of participatory attitude as having a key facilitating role in it. The concept is developed through reflexive narratives from the first five months of a sustainable renovation process. Characteristics of the participatory attitude identified here were sustained listening, bridging, demonstrating and eliciting. The attitude helped build mutual trust, which in turn engaged residents in reflecting on their everyday practices in relation to the future technical make-up of their home. Questions remain how well democratic aims were represented in the process. No residents were left behind, because system gaps were bridged.

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Users’ behaviour and indoor climate are two leading aspects that must be taken into account if we want the retrofitting of the housing stock to contribute to CO₂ reduction, comfort improvement and reduction of living costs. The integrated facade module evaluated in this paper, which constitutes an approach to zero energy renovation, includes a preliminary study for the identification of target occupants and their characteristics and requirements that will guide the design decisions. The proposed strategy primarily focuses on the case of social rental multi-family housing stock in the Netherlands, but should provide insights in the application of the concept in Europe. This paper presents the analysis of the adaptability of this solution to the Mediterranean climate, taking into account the specific characteristics of the occupants of this climatic zone. The results showed an improved performance of building after the application of the evaluated solution in southern Spain, but with lower savings on the energy demand than in the Netherlands, so the economic investment should be reduced in this case. Also, the inclusion in the solution of some variables, such as the forced night-time ventilation for passive cooling and the insulation thickness reduction, were tested and proved to be an optimisation of its performance in the Mediterranean climate. Overall, the study concluded that the proposed refurbishment strategy has the potential to be implemented in different climates, particularly if certain modification in the facade operation is considered.

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A number of facade solutions have been developed in recent years to solve the problem of large-scale renovation of housing. In the Netherlands, housing associations have the ambition to achieve an energy-neutral renovation approach, and so, some aim at energy neutrality. However, few address the complexity of multi-family rental dwellings and more importantly, the importance of user behaviour in the actual performance of the buildings. In current approaches, the zero energy target is sought for an average household. In this paper we present an approach to zero energy renovation in which the influence of occupants’ behaviour in building performance is taken into account to eliminate the uncertainties related to energy savings. The results are used to inform the design process regarding the amount of energy production required to reach zero energy performance, and the feasibility of the on-site energy production only with photovoltaic panels. The research showed large statistically significant differences on energy consumption between the different household types, which could contribute to pre-bound effects if these differences are not considered when calculating energy savings and return of investments. When considering scenarios based on behaviour after renovation, the difference between the lowest and the highest heating demand is reduced to 34%.@en

Solar Home Systems (SHSs) can fulfil the basic energy needs of the globally unelectrified population. With costs as one of the biggest barriers for SHS uptake, optimizing the system size with energy needs is crucial. Where most solutions focus only on the present needs, this work also addresses the future energy needs. The methodology includes extensive mapping of the current electricity needs in rural Cambodia through data analysis on existing SHSs in the field. Additionally, a 2-month field research was carried out in Cambodia to assess the qualitative state of electricity usage and investigate the future (2021) energy needs. A data analysis was performed on 111 SHSs (100 Wp, 1200 Wh).
SHS users were found to have a mean energy consumption of 310 Wh/day, with σ = 159 Wh. Most energy was consumed at night. The field research showed a clear demand for more energy and more appliances. The appliances attached to SHS in the future will be more diverse in power consumption and usage duration, resulting in a wide variety of energy consumption and high power peaks, causing fast and deep battery discharges. Three load profiles are presented. Solutions are discussed that can be applied to ensure the SHSs fit with future energy needs.@en

The ambition to renovate the post-war building stock to an energy-neutral quality is getting a lot of attention in social housing association and other institutional owners, financial institutions and users. The Energy Agreement for Sustainable Growth indicates that 300.000 dwellings have to be renovated in the Netherlands annually. An effective renovation plan has to be long-term, target the deep transformation of the existing building stock, and to significantly improve its actual energy performance towards nearly zero energy levels. This level of energy saving typically requires a holistic approach, viewing the renovation as a package of measures working together. Even though the need for refurbishment is urgent, the rate of renovation and the resulting energy savings are relatively low. Main barriers identified are related to the available investment funds, awareness, advice and skills and the separation of expenditure and benefit. To address these issues, the paper presents a prefabricated and integrated façade module that gives the possibility to improve the current energy performance up to zero energy, while ensuring minimum disturbance for the occupants, during and after the renovation. Given that the design and installation take this constrain into consideration, it is possible to reach zero energy by adding more efficient installations and energy generation, as well as taking possible behavioural changes into account. Moreover, the paper evaluates such a zero-energy refurbishment in terms of financial feasibility. The proposed approach results in a feasible solution, which achieves high energy savings and addresses the complex issue of integrated refurbishment.@en

To be able to develop and implement high-impact sustainable innovations in the built environment, researchers, product/-service developers and policymakers in the region of Rotterdam felt the necessity to work with users to prototype, test and validate potential solutions in real life situations. In collaboration with European partners initiatives, the Concept House Village in Heijplaat Rotterdam was developed. The inner-city docklands of Rotterdam is an area in transition and forms an ideal setting for a real life test bed for future sustainable urban living and working. In this chapter the history, ambitions, context and the partnership is described. Furthermore the accompanying research and development program is enlightened. Additionally the business modeling of Concept House Village as a R&D facility is considered.

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There are an estimated 170 active living labs across the globe. All have common elements but not all of them contribute to the delivery of sustainable living. Here we consider the business models of sustainability in living labs (SusLabs). Specifically we review four active living laboratories that are part of the SusLab North West Europe network. We show that the business cases are different for at least two reasons. One is that each SusLab project has a specific focus even though all are seeking to develop energy efficient innovative products, services or systems. Examples of focus include demonstration projects, knowledge generation through research and business to business development. The other is that each came about for different reasons which might include significant public or private sponsorship, or through academia-business co-creation, and this too is reflected in the business case. We also show that the business cases are not static, but may evolve over time as opportunities are created and as partners develop a clearer understanding of the potential of each SusLab. We propose that, based on a common definition of a SusLab, theoretical considerations and societal needs, as well as insights from the cases, it should be possible to build a business case for a SusLab which draws on knowledge rather than learning-by-doing.

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Building simulations are often used to predict energy demand and to determine the financial feasibility of the low-carbon projects. However, recent research has documented large differences between actual and predicted energy consumption. In retrofit projects, this difference creates uncertainty about the payback periods and, as a consequence, owners are reluctant to invest in energy-efficient technologies. The differences between the actual and the expected energy consumption are caused by inexact input data on the thermal properties of the building envelope and by the use of standard occupancy data. Integrating occupancy patterns of diversity and variability in behaviour into building simulation can potentially foresee and account for the impact of behaviour in building performance. The presented research develops and applies occupancy heating profiles for building simulation tools in order create more accurate predictions of energy demand and energy performance. Statistical analyses were used to define the relationship between seven most common household types and occupancy patterns in the Netherlands. The developed household profiles aim at providing energy modellers with reliable, detailed and ready-to-use occupancy data for building simulation. This household-specific occupancy information can be used in projects that are highly sensitive to the uncertainty related to return of investments.

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Large differences between the expected and actual energy consumption have been found in energy efficient dwellings. Research has shown that these differences are partially caused by occupant behaviour. The financing and payback periods of low carbon technologies are often uncertain because of the impact of the occupants on building performance. This translates into a reluctance to invest in deep renovation projects. The goal of this design-inclusive research project is to develop a solution for zero energy renovation that reduces the uncertainty on building performance cause by occupants' behaviour by reducing the uncertainty in design decisions and energy calculations. This investigation focuses on the identification of building type specific occupants and their characteristics, requirements and living practices. This paper presents the user research approach developed for the renovation process. The approach consists of statistical analysis of Dutch households, a monitoring campaign in the area of study and co-creation research through mock-ups, enactments and interviews. Case studies results are presented to highlight the effect of different household types on energy consumption and occupants' requirements, and point at the importance of taking into account household typology and socio-economic characteristics in energy calculations or building simulations, as well as occupant requirements in the design process.

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The ambition to renovate the post-war building stock to an energy-neutral quality is getting a lot of attention from social housing corporations and other institutional owners, financial organizations, and users. An effective renovation plan must significantly improve the current energy performance of a target building towards nearly zero-energy levels. A number of facade solutions have been developed in recent years to solve the problem of large-scale renovation of housing. In the Netherlands, several exemplary renovation projects have the ambition to achieve an energy-neutral objective. One such project is the 2ndSkin Façade refurbishment approach for post-war residential buildings. Nevertheless, the market intake of such renovation is currently very slow, as housing associations are reluctant to invest the increased cost of a zero-energy refurbishment, despite the energy savings and ongoing benefits for the occupants. Within the framework of the research project 2ndSkin, this paper presents a prefabricated and integrated façade module that provides the possibility to improve energy performance up to zero-energy use, while ensuring minimum disturbance for the occupants, both during and after renovation. Based on the proposed integrated refurbishment solution, the study presents a financial breakdown of this case-study concept - including options to lower the initial investment - in order to outline a more attractive business case. Firstly, three design variations, ranging from a standard external insulation upgrade to a zero-energy renovation, are compared, using a range of positive, average, and negative values for a series of financial and economic parameters. Subsequently, the financial performance of a zero-energy renovation investment is calculated for three different apartment properties with diverse market values, to determine the circumstances that can justify an energy renovation investment. The analysis showed that, for properties with an intermediate to high market value, the investment can be attractive under current economic and market conditions, but this attractiveness drops significantly for lower-cost properties such as social housing. The study objective is to develop both the technical solution and the related business case to support the implementation of zero-energy refurbishment strategies into diverse real estate market tiers of the residential building stock. @en

This paper deals with a green energy highway in the Netherlands. Here, the development of electric mobility and self-driving cars is introduced. The ideas of wireless power integration with green energy technologies - solar and wind is considered. In case of wind energy, conventional turbines and bladeless vortex are considered as options. Solaroads along the emergency lanes are also investigated. A Dutch highway A12 is considered as a case study and sizing of these energy sources for electric mobility is considered. A grid power demand profile is considered and number of EVs that can be charged hourly is calculated. A preliminary investigation of the combination of IPT and Self-Healing roads is considered in this study.@en

Developing technological solutions for the developing nations is more than simply re-sizing a prevalent solution from the developed world. Not only the environmental conditions, but also the technology usage varies greatly between the developing nations in sunnier latitudes around the world and the developed nations of north-western Europe. This paper sheds light on the various technical and non-technical factors to be considered for designing a standalone PV system for low-income households in emerging economies. The significance of the battery in a low-cost PV system is examined and the role of power electronics in such a system design is highlighted. Finally, the paper proposes a system design methodology. This paper presents an overview of the current initiatives in the Solar Home System landscape, and identifies gaps that can be potentially filled by technology.@en

This study investigates the effectiveness of direct feedback via a smartphone/tablet application on households’ energy consumption. Energy consumption levels and self-reports on various energy behaviours and attitudes were measured for a large sample of households (n = 519) who were either given direct feedback or only indirect feedback through bi-monthly overviews. Even though households with the direct feedback reported to have more energy awareness and indicated to have made more investments and changes in their behaviour, the direct feedback did not result in any significant energy savings. For the design of future direct feedback apps, it is essential to facilitate a households’ engagement with energy management.@en