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The design and assessment of net-zero buildings commonly focus exclusively on the operational phase, ignoring the embodied environmental impacts over the building life cycle. An analysis is presented on the consequences of integrating embodied impacts into the assessment of the environmental advantageousness of net-zero concepts. Fundamental issues needing consideration in the design process - based on the evaluation of primary energy use and related greenhouse gas emissions - are examined by comparing three net-zero building design and assessment cases: (1) no embodied impacts included, net balance limited to the operation stage only; (2) embodied impacts included but evaluated separately from the operation stage; and (3) embodied impacts included with the operation stage in a life cycle approach. A review of recent developments in research, standardization activities and design practice and the presentation of a case study of a residential building in Norway highlight the critical importance of performance indicator definitions and system boundaries. A practical checklist is presented to guide the process of incorporating embodied impacts across the building life cycle phases in net-zero design. Its implications are considered on overall environmental impact assessment of buildings. Research and development challenges, as well as recommendations for designers and other stakeholders, are identified.

Filament seals, such as brush seals and leaf seals, are investigated as a potential improved seal for gas turbine applications. As these seals operate in contact with the rotor, a good understanding of their stiffness is required in order to minimize seal wear and degradation. This paper demonstrates that the filament and complete seal stiffness is affected in comparable magnitudes by mechanical and aerodynamic forces. In certain cases, the aerodynamic forces can also lead to an overall negative seal stiffness which may affect stable seal operation. In negative stiffness, the displacement of the seal or rotor into an eccentric position causes a resultant force, which, rather than restoring the rotor to a central position, acts to amplify its displacement. Insight into the forces acting on the seal filaments is gained by investigating a leaf seal, which consists of a pack of thin planar leaves arranged around the rotor, with coverplates on either side of the leaf pack, offset from the pack surfaces. The leaf seal is chosen due to its geometry being more suitable for analysis compared to alternative filament seals such as the brush seal. Data from two experimental campaigns are presented which show a seal exhibiting negative stiffness and a seal exhibiting a stiffness reduction due to aerodynamic effects. An empirical model for the forces acting on leaf filaments is developed based on the experimental data, which allows separation of mechanical and aerodynamic forces. In addition a numerical model is developed to analyze the flow approaching the leaf pack and the interleaf flow, which gives an insight into the causes of the aerodynamic forces. Using the empirical and numerical models together, a full picture of the forces affecting leaf stiffness is created. Validation of the models is achieved by successfully predicting seal stiffness for a further data set across the full range of operating conditions. The understanding of aerodynamic forces and their impact on filament and seal stiffness allows for their consideration in leaf seal design. A qualitative assessment of how they may be used to improve seal operation in filament seals is given.

Urban environments provide opportunities for greater resource efficiency and the fostering of urban ecosystems. Brownfield areas are a typical example of underused land resources. Brownfield redevelopment projects that include green infrastructure allow for further ecosystems to be accommodated in urban environments. Green infrastructure also deliver important urban ecosystem services (UES) to local residents, which can greatly contribute to improving quality of life in cities. In this case study, we quantify and assess the economic value of five UES for a brownfield redevelopment project in Antwerp, Belgium. The assessment is carried out using the “Nature Value Explorer” modelling tool. The case includes three types of green infrastructure (green corridor,infiltration gullies and green roofs) primarily intended to connect nature reserves on the urban periphery and to avoid surface runoff. The green infrastructure also provides air filtration, climate regulation, carbon sequestration and recreation ecosystem services. The value of recreation far exceeds other values, including the value of avoided runoff. The case study raises crucial questions as to whether existing UES valuation approaches adequately account for the range of UES provided and whether such approaches can be improved to achieve more accurate and reliable value estimates in future analyses.

Abstract This article reviews the current status of research on urban green and blue infrastructure (GBI) in developing countries. We critically analyzed a total of 283 papers addressing urban GBI in selected developing countries in Africa, Asia, Latin America and the Caribbean (LAC), published between 2015 and 2019. The review aimed to a) analyze publication trends and typologies of urban GBI; b) identify innovative problem-solving measures using urban GBI, and c) understand priorities, differences and similarities in the deployment of urban GBI between the regions. The article identifies a growing interest in the urban GBI concept in the Global South, with a focus on local sustainable development. Urban GBI aims to address issues of urban greenery, land use policies, food security and poverty alleviation. There is a large variation in the number of articles across regions, with Asia, and particularly China, as the subject having a much larger number of publications when compared to LAC and Africa. We found that the focus of research topics varied between regions, reflecting regional development needs, so that urban agriculture research predominated in Africa, and green spaces and parks in Asia and LAC. GBI is still not implemented as a low-impact development or innovative strategy, except in China, where researchers have examined several cases of systemic GBI use for addressing urban issues. More recently, studies began exploring the linkages between nature and cities in light of global environmental issues such as biodiversity loss and climate change. We conclude with recommendations to further examine empirical evidence of urban GBI deployment and its outcomes in the Global South, that could contribute toward conceptualizing natural resource management in a multi-scalar, multi-dimensional, and multidisciplinary framework.

The experiment determined the technical and financial efficiency of five storage techniques, specifically designed for SRF poplar chips stored at the farm site in small (20 m3) piles. The treatments on test were: uncovered storage, storage under a temporary roof structure, cover under a semi-permeable fleece sheet, cover under two types of plastic sheet (i.e. white and black). Each treatment was replicated 3 times. Researchers monitored temperature and moisture content trends inside the piles, and determined dry matter losses at the end of the 170 days storage period. In general, piles under plastic cover presented opposite trends compared to all other piles. They acquired moisture rather than losing it, and showed gradual temperature trends instead of a typical peak-and-drop behaviour. Dry matter losses varied from 5.1% to 9.8%, and were highest for the uncovered treatment, and lowest for the plastic cover treatment. Under the conditions of north-western Italy, uncovered storage was a cost-effective option. Protecting the piles with some cover incurred more cost than it saved, resulting in a higher storage cost per unit energy. Although more expensive, sheltering the piles under a simple roof structure offered the benefit of a higher reduction of moisture content, which may turn the chips into a higher quality fuel. Of course, these results were closely related to the Southern European climate, and the specific year of the test. Occasional wetter years may overturn these results. © 2013 Elsevier Ltd. All rights reserved.

There are well-defined methods to measure the (increased) series resistance of PV panels in controlled laboratory conditions. However, the presence of various irradiance levels and partial shadows, in case of an outdoor installation, may affect the series resistance estimation. This paper focuses on the estimation of increased series resistance in outdoor conditions in various irradiance levels and partial shadow conditions. A diagnostic method that is able to detect an increase in series resistance based on fuzzy classifiers is presented and experimentally validated.

Vineyards cover about eight millions of hectares worldwide and their annual pruning generates a large amount of ligno-cellulosic biomass, potentially available for industrial and energy use. Commercial pruning residue harvesters are now available, which may allow cost-effective recovery. The study aimed at determining the quantity and the quality of pruning residues potentially derived from vineyard management. Data were obtained from 17 fields in Northern and Central Italy. Fields were harvested with seven different machines. The experimental design adapted to the necessities of field trials, but was adequate for testing the main sources of variability. Net residue yield varies around 1 oven dry tonne per hectare, with minor differences between grape varietals and harvesting technologies. Losses are still high, and are generally related to ineffective management techniques. Moisture content at harvest varies between 40% and 45%, whereas the higher heating value is slightly lower than that of forest fuels. Comminuted vineyard residues are unsuitable for firing residential boilers, due to the frequent presence of oversize and/or undersize particles. The application of pesticides does not result in any significant contamination with noxious chemicals, because these products are almost completely weathered before residues are recovered. In wine-producing regions, the recovery of vineyard pruning residue may represent a substantial source of industrial bio-fuel. © 2011 Elsevier Ltd.