Increasing Cellular Network Energy Efficiency for Railway Corridors

Modern trains act as Faraday cages making it challenging to provide high cellular data capacities to passengers. A solution is the deployment of linear cells along railway tracks, forming a cellular corridor. To provide a sufficiently high data capacity, many cell sites need to be installed at regular distances. However, such cellular corridors with high power sites in short distance intervals are not sustainable due to the infrastructure power consumption. To render railway connectivity more sustainable, we propose to deploy fewer high-power radio units with intermediate low-power support repeater nodes. We show that these repeaters consume only 5% of the energy of a regular cell site and help to maintain the same data capacity in the trains. In a further step, we introduce a sleep mode for the repeater nodes that enables autonomous solar powering and even eases installation because no cables to the relays are needed.

Towards Solar Decathlon: Concepts for a Sustainable Urban Water Management in a new eco-district

Gianluca Antonio Paglia

Water is rarely considered to be a crucial aspect in sustainable housing. In fact, water sustainability in eco-districts and in ecological architecture is frequently limited to recycling and reuse solutions. Why less water? What could explain the choice of an installation, of a specific strategy or of a criterion trying to decrease water needs? Terms as ecological footprint or sustainability are becoming more and more used, however, how can sustainability be measured? What does sustainable water mean? What are the parameters that quantify the ecological footprint of a water management system? Within this project, some possible concepts of optimization and valorization of sustainable urban water system have been defined and explored. Numerous studies about water management, water distribution, sanitary technologies, recycling, etc. have already been done. Nevertheless, it is less common to identify the reasons that are able to justify a reduced consumption of water. Eco-district labels propose several solutions for sustainable water, however they are limited by scale or simply focused on one stage of the water cycle. The aim of this project is then to consider water from a larger point of view: through a Life Cycle Analysis approach, needs and properties of different urban water management systems are compared and evaluated. The scale considered for such reflections is effectively a central parameter; in this case, hypothesis will be applied to collective habitations inserted in a district and part of a specific urban context: the city of Fribourg. The urban environment has particular features in relation to surrounding rural areas: energy exchanges, hydrology characteristics and limited ecosystems. The relationship between the use of natural resources and urban development is becoming more and more important; the purpose of this thesis is then to define a methodology able to suggest a sustainable use of water through environmental, political and economic issues. A real urban case study with its current water management system defines what has to be analyzed and allows evaluating the limits and the possible enhancements of such system. Thus, in order to have an idea about the potential of sustainable water management solutions, an ambitious analysis of energy related to water uses and disposals is created and is used to show the reasons for change in a real model as the city of Fribourg. A comparison between two extreme scenarios of Fribourg’s selected zones is finally developed, discussed and implied in the conclusions through specific actions and facts. The results show that a high potential of improvements exist. Using them to elaborate new strategies in collaboration with the several stakeholders contacted may contribute to achieve many of today’s objectives for a sustainable urban water management. The best scenario, chosen with a new concept of eco-label, summarizes and concludes the analysis.

2015

The energy transition – an integrative analysis

Claudia Rebeca Binder Signer

The ongoing energy transition is seen as a key component for the transition towards a more sustainable society. An important component in the move towards a sustainable energy system is the transition from a mainly centralized, fossil-fuel system to a more localized, renewable one. This transition, however, requires not only the development of new energy technologies but also radical, systemic shifts in deeply held values and beliefs, in patterns of social behavior, and in governance regimes. Thereby the ecological, technical and social systems have to be conceptualized as Social-Ecological-Technical Systems (SETS) and new integrative, interdisciplinary research approaches are needed which consider the interaction between these subsystems. We present results of an integrative analysis of transitions which occurred in two Austrian energy regions during the last 20 years. We show (i) how institutional development and infrastructure development are related to each other within time; (ii) whether and how demand and supply of renewable energy carries can be met at the regional level; and (iii) which factors in household behavior affect decision making- and consequently energy demand in the housing sector. Finally, we present some thoughts on the resilience of such transition processes and discuss the need for further research. Socio-ecological transitions are defined as transitions between different societal regimes and co-dependent ecological changes. In the past, two major transitions have occurred as are the transition from the hunter and gatherers society to the agricultural society and from the latter to the industrial society. These transitions have both been characterized by an increased material and energy consumption per capita and an increase in urban population. Scholars have stated that we are in the middle of a new transition maybe towards a sustainable society. This transition is likely to encompass a further increase in the share of the population living in urban areas, however linked to significant efforts to change the metabolism of cities by e.g., transforming the energy system away from a fossil fuel based towards a renewable energy system. The experiences of various scholars have led to the insight that this transition cannot be analyzed with disciplinary approaches alone. They have to be dealt with in an integrative, interdisciplinary way that considers the dynamics and interactions between social and ecological systems. This presentation will show how inter- and transdisciplinary research could be framed to better understand, simulate, and provide policy recommendations for the ongoing transition. These approaches significantly feed into the new research foci in urban ecology, as they specifically study the dynamics within and the interaction between the social and ecological systems. Empirical results for the transition of energy regions will be presented.

2016

Urban cells: Extending the energy hub concept to facilitate sector and spatial coupling

Kavan Javanroodi, Amarasinghage Tharindu Dasun Perera, Yi Wang

The rapid growth of urban areas and concerns over climate change make it vital to improve the energy sustainability of cities. Understanding the complex interactions within different sectors (sectoral) and localities (spatial) of cities plays a crucial role in improving efficiency and sustainability, which is extremely challenging due to the complex urban morphology. State-of-the-art energy concepts do not facilitate a detailed consideration of both sectoral and spatial coupling that energy infrastructure maintains at the urban scale. This has become a significant challenge when designing interconnected urban energy infrastructure. The Urban Cell concept is introduced to address this bottleneck. A novel computational model using a modular approach is introduced to create an interconnected urban infrastructure, including the energy, building, and transportation sectors. Optimal sizing of the distributed energy system (including renewables, energy storage, and dispatchable sources) and optimal urban morphology is determined within a modular unit. A game-theoretic approach is used to model the interactions between urban cells (modular units). The study revealed that the urban cell concept can reduce the net present value of the interconnected energy infrastructure by 37% while increasing the installed renewable energy capacity by 25%. This demonstrates the benefit potential of urban cells and the importance of considering interactions between different sectors and different parts within a city. The Urban Cell concept can be used to present the complex interactions maintained within a city.