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Life Cycle Assessment of District Heating Pipes; Comparing Polyurethane with Polyethylene Terephthalate Insulation
Get PDFDistrict Heating (DH) system has proven to be a viable solution for delivering heating, hot water, and cooling services to the end-users, in that it represents the most suitable energy solution for satisfying urban heat and cold demands. So, in order to keep evolving, district heating must constantly develop in response to the growing demands of a society striving towards sustainability. By this, the sustainability of this system needs to consider further aspects of material use and deploy a large-scale material efficiency which could be a crucial factor in obtaining a variety of additional environmental and economic benefits. In a typical DH distribution system, the pipe is an integral part. The commonly used DH pipe is the pre-insulated bonded pipe with steel carrier pipe, rigid polyurethane (PUR) foam, and high-density polyethylene (HDPE) casing. However, PET foam has been suggested as a suitable substitute for PUR foam.
This thesis therefore presents a comparative study to benchmark the environmental impacts for the manufacturing of polyurethane (PUR) foam insulated pipe and a conceptual polyethylene terephthalate (PET) foam insulated pipe based on Life Cycle Assessment methodology. The functional unit is taken to be “the production of 2.42 m length of a DN100 pre-insulated pipe”.
The results of life cycle assessments show that the process of manufacturing PUR foam insulated pipe has the largest environmental impacts across the selected impact categories, while the emissions are mostly noticeable in climate change and fossil depletion, which is mostly influenced by raw materials extraction and refinement. An evaluation of material layers indicated that steel pipe gives off the highest emission of all the material components in the pipe and methylene diphenyl diisocyanate (MDI) in the PUR foam. A comparison of insulations materials also showed that virgin PET foam has 28% less impact and when virgin PET in the PET foam is replaced with recycled PET, the impact was further reduced by up to 60%, thereby confirming it to be a suitable alternative. Furthermore, a sensitivity analysis showed that Substituting virgin PET foam with recycled PET foam in the overall system achieved the highest environmental benefits by approximately 12% and this savings in impacts is noticeable across almost all impact categories
It’s not enough to be right! The climate crisis, power, and the climate movement
Get PDFThe demands of the climate movement ‐ for rapid and profound change ‐ are based on scientific findings and the political commitments to the Paris Agreement. The activists are, therefore, factually “right”. However, being right is not enough to justify or to accelerate the practical implementation of knowledge and decisions. We explain which social factors are at work, and how the climate movement can benefit if they incorporate these factors into actions for social change
Potential of the public space to promote environmental behavior
Get PDFIt is widely recognized that individual environmental behavior plays an important role in curving climate change but it remains unclear how it could be promoted. This paper studies the potential of the public space enabling action. We use an explanatory social mechanism approach to examine what distinctive features of the public space facilitate the implementation of different strategies aimed at overcoming internal and external factors or barriers hindering action and how they do it. A fictitious intervention serves as an example to explain the link between space and action. Our deep and fined- grained analysis points out that accessibility features of the public space and situational featuresfacilitating its use are preconditions for the implementation of all the revised strategies. Visual accessibility facilitates the implementation of social norm-based interventions involving active participation, creating the conditions for other strategies to work, while physical accessibility represents an opportunity to implement availability-based interventions by providing quickly and easy access to the promoted products and services. Situational features refer to the physical characteristics of the space, influencing the nature and scope of the intervention by determining space and infrastructure constraints. Accessibility and possibilities for use lead to multiple forms of social exchange. All the reviewed strategies deal in one way or another with different forms of communication, positioning information as the strategy with the widest range of action. The public space also facilitates civic-based strategies aimed at increasing the participation of citizens on decision-making at administration level. Finally, priming and salience-based strategies can be used to create full lived-in experiences, reinforcing action through sensation and perception processes. The study shows the potentiality of the public space curving climate change towards more sustainable cities and societies through the implementation of a wide range of interventions aimed at making environmental behavior visible and accessible to all
The unexpected persistence of non-corporate platforms: The role of local and network embeddedness
Get PDFThe Covid19-pandemic has accelerated processes in which digital platforms, privileged by their critical size, become central instances of urban life. While most scholars associate platform urbanism with transnational platform corporations, such as Amazon or Facebook, local non-corporate platforms unexpectedly persist despite lacking critical size. This article analyzes processes through which non-corporate platforms are created, maintained, disseminated, and locally implemented; given this type of platform's absence of critical size. We explain the persistence of local non-corporate platforms by drawing on the concept of embeddedness. Embeddedness accounts for non-market-based, i.e. socially and culturally influenced behavior, that shapes economic interactions. We distinguish between network embeddedness, in which organizations maintain permanent and exclusive relationships with one another, and local embeddedness, which combines Hess' (2004) notions of societal embeddedness and territorial embeddedness. This article is empirically grounded on an analysis of two most different ways of creating and maintaining, disseminating, and locally implementing non-corporate platforms: Platform cooperativism and free/libre open-source software-based platforms (FLOSS-based platforms). Two empirical case studies of collaboratively governed Western-European non-corporate platforms, Gebiedonline and Decidim, respectively inform the analysis of platform cooperativism and FLOSS-based platforms. Gebiedonline is a platform cooperative through which neighborhood and theme-specific platforms are created. Decidim is a FLOSS-based platform that is mainly used for civic and political participation processes. We find that governments and civil society stakeholders create non-corporate platform technology by disentangling processes related to the creation, maintenance, and dissemination of platform technology from platform implementation processes. Following platform creation, platform maintenance is embedded in a network. Non-corporate platforms pool cost-intensive technology maintenance, while platform implementation necessarily takes place in a locally embedded manner
Sustainable Insulation for Sustainable DHC
Get PDFThe piping network is the essence of DHC. Its insulation is fundamental for its correct and efficient functioning. State of the art DHC networks are insulated with polyurethane (PU) foam, which presents outstanding mechanical and insulating properties. However, the high toxicity of the diisocyanates (European Chemical Agency, 2008) required for its production and the recently approved European Restriction on their Use (European Commission, 2020) highlight the need for sustainable alternatives.
Polyethylene terephthalate (PET) foam has been previously identified as a promising candidate for DHC given its mechanical properties (Ramnäs, 2008) and high insulation capacity retention, due to slow gas diffusion (Mangs, 2005) . However, its behavior upon ageing remains unexplored. Without this knowledge, the material cannot be reliably introduced in the market. The objective of this work is to experimentally investigate PET foam’s ageing behavior, with a focus on the effects of thermal cycling, thermally induced crystallinity and hygrothermal degradation on its mechanical properties.
Different ageing trials were conducted in an environmental chamber. The effects on the mechanical properties and crystalline structure were evaluated. No degradation was found in the scenarios covered by this study. Service temperature over 100 °C is found possible thanks to thermally induced crystallization
Controlled experiment of underwater vision-based mapping: A preliminary evaluation
Get PDFUnderwater vision-based mapping (VbM) constructs three-dimensional (3D) map and robot position simultaneously out of a quasi-continuous structure from motion (SfM) method. It is the so-called simultaneous localization and mapping (SLAM), which might be beneficial for mapping of shallow seabed features as it is free from unnecessary parasitic returns which is found in sonar survey. This paper presents a discussion resulted from a small-scale testing of 3D underwater positioning task. We analyse the setting and performance of a standard web-camera, used for such a task, while fully submerged underwater. SLAM estimates the robot (i.e. camera) position from the constructed 3D map by reprojecting the detected features (points) to the camera scene. A marker-based camera calibration is used to eliminate refractions effect due to light propagation in water column. To analyse the positioning accuracy, a fiducial marker-based system –with millimetres accuracy of reprojection error– is used as a trajectory’s true value (ground truth). Controlled experiment with a standard web-camera running with 30 fps (frame per-second) shows that such a system is capable to robustly performing underwater navigation task. Sub-metre accuracy is achieved utilizing at least 1 pose (1 Hz) every second
Ressourceneffiziente Planung von Wohnsiedlungen: Hamburg (Post-1990er) und Niš (Post-Sozialismus) Narrative
Get PDFThis publication is a collection of interviews of residents living in the Neuallermöhe neighborhood in Hamburg and the new housing development on Somborska Boulevard in Nis with the aim of finding out what challenges and opportunities exist within their developments and what aspects could be improved
Urban allotment gardens in the contemporary city. Contested ownership arrangements and new greenspace solidarities in Basel, Hamburg and Copenhagen
Get PDFSatellite gravimetry for climate model evaluation
Get PDFGlobal coupled Earth System Models (ESMs) are important for predicting future climate conditions. To assess the quality and reliability of ESMs it is crucial to evaluate them against independent observations. In this thesis, land water storage-related variables from ESMs taking part in the Coupled Model Intercomparison Project Phases 5 and 6 (CMIP5 and CMIP6) are compared to observed terrestrial water storage (TWS) changes from the Gravity Recovery And Climate Experiment (GRACE) and its Follow-On (GRACE-FO) satellite missions. This thesis is the first study to provide a comprehensive assessment of ways in which space gravimetric measurements can be utilized to evaluate coupled ESMs, thereby tackling several challenges of such a comparison:
Apart from external forcing data (e.g., the Sun's energy and greenhouse gas concentrations), CMIP ESMs are not constrained by observations, but evolve freely over time after being initialized. As a consequence, over long time spans they reproduce the climate variability in a statistical sense only, but not the exact timing of particular events. Thus, when analyzing (long-term) climate projections, a direct comparison to observed time series is not feasible, but higher order metrics as the linear trend, seasonal cycle, and interannual variability have to be utilized. Furthermore, discrepancies between observed TWS (full integrated water column, possibly superimposed by non-hydrological mass changes) and modeled TWS (representing only soil moisture and snow) regionally hamper the interpretation of results.
In the comparison of a CMIP5 ESM ensemble with GRACE observations, simulated long-term wetting and drying trends are found to be consistent with observed TWS trends in several regions of the world (e.g., the Mediterranean, Southwestern United States, Central Asia). However, it is shown that interannual variations obscuring long-term trends in TWS can have a large influence over 30 years and more, which regionally prevents reliable conclusions about long-term wetting or drying from the short GRACE time series. In addition to long-term trends, the seasonal cycle and interannual variations of TWS in a CMIP6 multi-model ensemble are assessed with respect to present-day observed conditions. The model data are also analyzed for potential future changes of TWS variability, as these might be an important target for a future gravity mission with enhanced sensitivity. In contrast to long-term climate projections, decadal predictions can directly be compared on time series level, because they are frequently initialized with observed states of atmosphere and oceans. To this end, a GRACE-based TWS reconstruction is used to evaluate decadal climate predictions from CMIP5 and CMIP6 with the result that they provide skillful forecasts of TWS anomalies in markedly humid climates for two years and more into the future.
Overall, this thesis highlights mutual benefits of climate modeling and geodesy: On the one hand, satellite-observed TWS has a great potential to validate the performance or to hint at shortcomings of ESMs for land water storage-related variables. On the other hand, ESM output can provide information on expected climate signals in TWS, which is important for future plans in space gravimetry aiming at the long-term monitoring of climate variations