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Šetří letní čas energii? Důkaz z České republiky / Does Daylight Saving Time Save Energy? Evidence from the Czech RepublicČastorálová, Lucie January 2019 (has links)
A b s tra c t The recent discussion of the European Parliam ent, member states, and citizens triggered the question whether there is s till a need for bi-annual clock shifting from the perspective of energy savings. Employing the difference-in-differences method on hourly data on electricity consumption between 2006 and 2017, the study con cludes th a t daylight saving tim e policy reduces aggregate electricity consumption by 0.35 % in the Czech Republic. Moreover, daylight saving tim e leads to 1% savings on domestic residential electricity consumption. Overall, daylight saving tim e increases electricity consumption in the morning, bu t decreases electricity consumption in the evening by greater amount. We have estimated th a t more than 65 % of to ta l electricity savings attributable to daylight saving tim e arose from effect of the daylight saving tim e on residential electricity consumption. 1
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Unapređenje metoda za utvrđivanje uštede emisija gasova s efektom staklene bašte pri korišćenju biogasa iz kukuruzovineVišković Miodrag 04 October 2019 (has links)
<p>Kukuruzovina je žetveni ostatak i potencijalni supstrat za proizvodnju biogasa. Direktivom 2018/2001 definisan je tzv. RED metod za obračunavanje ušteda emisija gasova s efektom staklene bašte– GHG. Metod je primenjiv za silažu kukuruza i stajnjak kao supstrat za proizvodnju biogasa, ali se na neadekvatan način obračunavaju emisije GHG za kukuruzovinu. Cilj je bio da se predlože unapređenja RED metoda kojima bi se prevazišli identifikovani problemi, kao i da se ispita uticaj primene unapređenog metoda na ocenu ušteda emisija GHG energetskog iskorišćenja biogasa iz kukuruzovine, tj. na ocenu održivosti. Uštede emisija GHG za sve razmatrane slučajeve primene RED metoda u osnovnoj i unapređenoj formi, imale su vrednost nižu od postavljenog kriterijuma od 70 %, tj. nisu održivi. Predloženo je da se RED metod unapredi ukidanjem pravila da se ne obračunavaju emisije GHG pre ubiranja žetvenih ostataka i da je potrebno da se navede da je ostatak fermentacije ko-produkt proizvodnje i korišćenja biogasa, kao i da je primena alokacije emisija GHG na biogas i ostatak fermentacije obavezna u slučaju primene ostatka fermentacije na polja sa kojih nisu ubirani žetveni ostaci.</p> / <p>Corn stover is a crop residue and potential substrate for biogas production. Directive<br />2018/2001 defines so-called RED method for determination of greenhouse gas (GHG)<br />emission savings. In the case of energy utilization of biogas produced from corn stover,<br />savings are calculated in an inadequate manner. The objective was to suggest the<br />improvements of the RED method in order to overcome the identified problems, as well<br />as to investigate the impact of the application of the improved method on the evaluation<br />of GHG emission savings, i.e. the the sustainability evaluation. The results of the GHG<br />emission savings, using the basic and the improved forms of RED method, show that all<br />considered cases had a value lower than the set criterion of 70%, i.e. they are not<br />sustainable. It was suggested to improve the RED method by abolishing the rule that<br />GHG emissions prior to collection of crop residue are not accounted. Also, it should be<br />noted that the digestate is a co-product of biogas production as well that the application<br />of the GHG emissions allocation to biogas and the digestate is mandatory in the case<br />when digestate is used on fields other than those used for substrate provision.</p>
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Adapter les modèles de chauffage et climatisation des bâtiments en puissance à l'échelle du quartier / Adapting buildings heating and cooling power need models at the district scaleFrayssinet, Loïc 26 October 2018 (has links)
Les modèles énergétiques des bâtiments à l’échelle du quartier sont généralement simplifiés pour faire face au manque de données et pour réduire le coût de calcul. Cependant, l’impact de ces simplifications sur la validité des modèles n’est pas systématiquement analysée, en particulier lorsqu’on s’intéresse à la courbe de charge. Pour combler ce manque, une méthodologie permettant de quantifier la validité des simplifications, notamment vis-à-vis de la courbe de charge, est proposée. Cette méthodologie est appliquée aux simplifications couramment utilisée pour les modèles thermiques d’enveloppe de bâtiments grâce à une plateforme numérique développée dans le cadre de cette thèse. Cette plateforme permet de générer et simuler automatiquement des modèles énergétiques de bâtiments, avec différents niveaux de détails, à partir de données issues de systèmes d’information géographique. La parallélisation des simulations énergétiques des bâtiments est utilisée à l’échelle du quartier, afin de tirer avantage de la structure du modèle global et de réduire les temps de calculs. La définition d’indicateurs spécifiques selon l’objectif de simulation apparait clairement comme l’étape essentielle lorsque l’on s’intéresse à la courbe de charge. Les résultats indiquent que la puissance est plus sensible aux simplifications que la consommation annuelle d’énergie. Les différents effets induits sont quantifiés et analysés physiquement. La capacité de l’échelle du quartier à atténuer les impacts des simplifications et d’intégrer les données statistiques est démontrée. La quantification des impacts des simplifications permet de guider l’adaptation des modèles vis-à-vis des objectifs de simulation et vis-à-vis des contraintes techniques. Cette contribution a pour objectif d’améliorer la performance des simulations énergétiques à l’échelle de la ville, et de favoriser leur développement, afin de répondre aux enjeux futurs. / District-scale building energy models are generally simplified to cope with a lack of data and to reduce computational cost. However, the impacts of these simplifications on model accuracy are not systematically studied, particularly when considering power demand. The present manuscript introduces a methodology to determine the suitability of any simplifications, notably those at the district scale, and considering the power demand. This methodology was applied to usual simplifications of the building envelope model thanks to a specific platform developed in the frame of this thesis. This platform enables automatically generating and simulating building energy models with different modelling levels of detail from geographical information systems. The parallelisation of the building energy simulations was notably implemented at the district scale in order to benefit from the model structure and to efficiently reduce the computational duration. The definition of indicators related to specific simulation objectives appears to be a necessary step when focusing on power demand. The results show a higher sensitivity to simplifications of the power demand than the annual energy consumption. These effects are quantified and physically analysed. The district-scale ability to attenuate the impacts of simplifications and to integrate statistical sources of data were demonstrated. The resulting quantification of the impacts of the simplifications made it possible to guide the adaptations of models to the simulation objectives and to the technical constraints. Such contribution aims to increase the efficiency and to favour the development of city-scale energy simulations, which are particularly needed to cope with future challenges.
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Alternativa isoleringsmaterial : Aerogel inom sjöfarten / Alternative Insulation Materials : Aerogel in shippingJohansson, Daniel January 2019 (has links)
Detta arbete handlar om att med en teoretisk modell kunna beräkna fram de olika mängder värmeförluster som vissa isoleringsmaterial släpper igenom. Syftet med detta arbete är att undersöka om ett specifikt isoleringsmaterial som vanligtvis inte används inom sjöfarten har möjligheten att sänka energin som försvinner igenom isoleringsmaterialen. De metoder som användes är en teoretisk modell som byggdes för att kunna använda de olika isoleringsmaterialens värmekonduktivitet för sedan kunna beräkna de teoretiska värmeförlusterna. Resultatet visar att aerogel skulle vara lämpligt för användning inom sjöfarten tack vara sina egenskaper och isoleringsförmåga som är mycket bättre än mineralull. / This work is about using a theoretical model to calculate the various amounts of thermal losses that some insulation materials release. The purpose of this work is to investigate whether a specific insulation material that has not been properly tested in shipping has the potential to lower energy that passes through the insulation materials. The methods used are that a theoretical model was built to use the thermal conductivity of different insulation materials in order to calculate the theoretical heat losses. The result shows that aerogel would be suitable for use in shipping thanks to its properties and insulation ability, which is much better than mineral wool.
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Exploring the strategies to implement a sustainable energy program in Hong Kong Public HospitalsTing, Terry 01 January 2017 (has links)
Healthcare is one of the most energy-intensive industries because of its 24 hour-a-day and 7-days-a-week operation model. Climate change, due to environmental pollution, has increased the incidence of respiratory disease, cardiovascular disease, and cancer, which further overload the financial burden of our healthcare system. The National Health Service Sustainable Development Unit suggested that a sustainable healthcare sector also requires using their resources in an efficient and responsible way. Hong Kong public hospitals are facing this problem along with high energy expenditure. The purpose of this qualitative, multiple site case study was to explore strategies for Hong Kong's public hospital leaders to develop and implement a sustainable program to reduce energy consumption. A purposive sample consisted of five local public hospital leaders that had successfully implemented a sustainable energy at their hospitals and received the 2014 Certificate of Merit of The Hong Kong Awards for Environmental Excellence. Semistructured interviews and document reviews were the data analysis methods for this study. The findings from the data analysis suggested that five major themes arose from the data: (a) external and internal driving forces, (b) leadership, (c) governance, (d) building a sustainable culture, and (e) performance measures. The recommendations of this study may lead to improving the use of energy in an efficient and responsible manner at the local public hospitals, reducing the hospital energy consumption cost, and reducing the disease incidences caused by environmental pollution.
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Saving for Change : A field study of Saving Groups impact on women’s empowerment in UgandaBörjeson, Sanna January 2019 (has links)
This thesis examines the role self-help microfinance Saving Groups play in women’s empowerment in villages in Mbale district, Uganda. Central for the study is to identify the challenges and opportunities that participation in Saving Groups brings in women’s everyday life. The thesis is a result of a qualitative field study in Uganda, where eleven mothers attending Saving Groups in the villages Nashikhaso, Bubuyera and Mulyuli were interviewed. The findings show that loans from the groups have allowed the interviewees to improve their farming and thereby gain an annual income which has led to several life-changing opportunities. The ability to pay for children’s education is recognized as most valued for the women’s self-esteem, self-confidence and hope for a better future. Moreover, the findings show that even though the Saving Group’s function as a financial instrument is important, their function as a center where women can socialize and find support and knowledge may be even more vital for women’s empowerment. Patriarchal structures are affected since the Saving Groups have given women that want to make a change an arena in which to do so. Thus, through the group, women have entered a traditionally men-only zone where they redefine roles and norms.
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Utvärdering av energibesparingspotential vid tillämpning av värmepump i diskmaskin : OBS! Sekretessbelagd tills vidare / Evaluation of energy saving potential by the applicatin of a heat pump in a dishwasherJoensen, Mortan, Nilsson, Maja January 2009 (has links)
<p>För ett genomsnittligt småhus i Sverige idag går ca 5000 kWh till hushållsel. Av dessa 5000 kWh går 7% till att driva diskmaskiner. Effektiviseringen av diskmaskiner har framförallt strävat efter en låg vatten- och energianvändning, en kort processtid samt en effektiv rening av disken.</p><p>Det finns dock gränser för hur effektiva diskmaskinerna kan göras med traditionell teknik. Därför har producenter under de senaste åren börjat se sig om efter mindre traditionella metoder som till exempel bruket av en värmepump för att få ned energiförbrukningen.</p><p>Syftet med det här examensarbetet har varit att ta fram systemlösningar för värmepump i diskmaskin samt att utvärdera energibesparingspotentialen i denna tillämpning.</p><p>Målet har varit att ta fram och beskriva de möjliga systemlösningar som uppstår vid en idégenerering. Att välja ut två lösningar för närmare undersökning, att bestämma en lämplig kompressoreffekt samt att beräkna energibesparingen dessa lösningar ger.</p><p>En litteraturstudie har gjorts av teknik och tillämpningar inom området, som till exempel värmeväxlaranvändning i diskmaskiner samt användandet av värmepumpar i andra vitvaror. Denna litteraturstudie följdes upp av en idégenerering, som tar hänsyn till möjliga värmekällor och –sänkor. Idégenereringen gav upphov till två systemlösningar som modellerades i MATLABs Simulink för att en lämplig kompressoreffekt och storleken på energibesparingen skulle bestämmas.</p><p>De två utvalda lösningarna ifrån idégenereringen var utomhusluftlösningen, där värme hämtas från uteluften och energilagerlösningen, där värme hämtas ur ett energilager. I båda lösningarna överförs värmen till det kalla ingående vattnet.</p><p>Energiåtgången för utomhusluftlösningen var beroende av köldmediets förångningstemperatur och modellering av lösningen visade att energiåtgången var 0,25 kWh vid en förångningstemperatur på -10°C, och 0,18 kWh vid 5°C. Vid modellering av energilagerlösningen påvisades en energiåtgång på 0,23 kWh. Slutsatsen som drogs var att kompressorn vid energilagerlösningen skall leverera en effekt på 240 W till köldmediet.</p> / <p>For an average detached house in Sweden today about 5000 kWh are used for household electricity. Of these 5000 kWh 7% are used to run dishwashers. The streamlining of dishwashers has above all strived for a lower water and energy use, a short process time along with a more efficient cleaning of the dishes.</p><p>There are however limits for how efficient the dishwashers can be made with traditional technology and acceptable costs. Therefore producers have, during recent years, started looking for less traditional methods, for example the use of a heat pump to reduce the energy use.</p><p>The purpose of this examination work has been to find system solutions for an application of a heat pump in a dishwasher and to evaluate the possible energy saving for each solution.</p><p>The goal has been to find and describe possible system solutions, which came up during the idea generation. To choose some of these for a closer investigation, to decide a fitting mechanical power for the compressor and to calculate the energy saving these solutions give rise to.</p><p>The method has consisted of a literature study, an idea generation, which takes the heat sources and sinks in consideration and a modelling in MATLAB’s Simulink of the selected solutions from the idea generation, which has been used to fit a mechanical power for the compressor.</p><p>The result of the idea generation was two solutions, an outdoor air solution, which collects heat from the outdoor air and gives it to the cold water which enters the machine and a energy storage solution, which collect heat from a heat stock to give to the cold entering water. A modelling of these show an energy usage of 0,24 respectively 0,17 kWh for the outdoor air solution, with a heat source temperature at 10 °C respectively 5°C and a energy usage of 0,22 kWh for the energy storage solution for one round.</p><p>The conclusion that was drawn was that the compressor of the energy storage solution should deliver a mechanical power of 240 W to the refrigerant.</p>
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Nonlinear phonocardiographic Signal ProcessingAhlström, Christer January 2008 (has links)
The aim of this thesis work has been to develop signal analysis methods for a computerized cardiac auscultation system, the intelligent stethoscope. In particular, the work focuses on classification and interpretation of features derived from the phonocardiographic (PCG) signal by using advanced signal processing techniques. The PCG signal is traditionally analyzed and characterized by morphological properties in the time domain, by spectral properties in the frequency domain or by nonstationary properties in a joint time-frequency domain. The main contribution of this thesis has been to introduce nonlinear analysis techniques based on dynamical systems theory to extract more information from the PCG signal. Especially, Takens' delay embedding theorem has been used to reconstruct the underlying system's state space based on the measured PCG signal. This processing step provides a geometrical interpretation of the dynamics of the signal, whose structure can be utilized for both system characterization and classification as well as for signal processing tasks such as detection and prediction. In this thesis, the PCG signal's structure in state space has been exploited in several applications. Change detection based on recurrence time statistics was used in combination with nonlinear prediction to remove obscuring heart sounds from lung sound recordings in healthy test subjects. Sample entropy and mutual information were used to assess the severity of aortic stenosis (AS) as well as mitral insufficiency (MI) in dogs. A large number of, partly nonlinear, features was extracted and used for distinguishing innocent murmurs from murmurs caused by AS or MI in patients with probable valve disease. Finally, novel work related to very accurate localization of the first heart sound by means of ECG-gated ensemble averaging was conducted. In general, the presented nonlinear processing techniques have shown considerably improved results in comparison with other PCG based techniques. In modern health care, auscultation has found its main role in primary or in home health care, when deciding if special care and more extensive examinations are required. Making a decision based on auscultation is however difficult, why a simple tool able to screen and assess murmurs would be both time- and cost-saving while relieving many patients from needless anxiety. In the emerging field of telemedicine and home care, an intelligent stethoscope with decision support abilities would be of great value.
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Did Consumers Really Change Their Consumption Habits After the 2008 Recession? A Look into Consumer Expenditure Using Milton Friedman's Permanent Income HypothesisSaisekar, Avantika 01 January 2012 (has links)
This paper focuses on the consumer expenditure habits in the years following the 2008 recession as compared to Milton Freidman’s Permanent Income Hypothesis. Panel data collected at the household level from the Consumer Expenditure Survey was used to analyze the change in consumption based on the change in income for the years 2009, 2010 and 2011. To achieve a greater understanding of expenditure patterns, this essay also analyzes the income elasticity of demand for elastic goods including expenditure on apparel, food eaten at restaurants, entertainment and transportation. With the use of panel and time series regressions we find that the Permanent Income Hypothesis holds true and consumers only marginally responded to a change in income in their consumption patterns. We hypothesize that the large spike in savings that was seen in May of 2008 resulted because of low consumer confidence, which in turn lead to a change in transitory consumption. Furthermore, we find that older adults spent more money on elastic goods than younger adults. This may be because older adults tend to have other assets that can financially support them in the case of a drastic change in income.
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Saving Motivations: A Study of Faith-Based Community Organizing in Pomona, CaliforniaLuttrull, Emily 30 April 2010 (has links)
In this thesis, I seek to engage with broad questions regarding religion and its interaction with the secular political world by examining a specific historical trend and a particular case study example of that phenomenon. In the American Christian tradition, religion and social justice have become inseparable entities; indeed, the Christian tradition has a long-standing relationship with justice initiatives in the United States. This relationship has taken many forms over the past two centuries. A current trend in Christian civic engagement in the United States is involvement with community organizing – which itself is a relatively new method of pursuing the cause of justice. Since the onset of community organizing, its relationship to religion in general and to Christianity in particular has been a defining characteristic of the movement. Over time, tensions have arisen within both the theory and practice of organizing that have inevitably had an impact on the religious groups and individuals participating in it. Those tensions include the question of why individuals should organize, and issues with the extremely delicate nature of the organizer-community relationship. This thesis examines how Christian theologies have addressed those tensions using the example of the First Presbyterian Church of Pomona, California. In short, I will argue that certain Christian theological values serve to answer those tensions effectively enough to motivate long-term organizing, particularly though scripture-based religious education.
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