Dissertations / Theses: 'CO2 emissions effect on E performance'

1

Grundström, Gustav, and Isabelle Miedel. "Sustainable Investing : On the relation between sustainability rating and greenhouse gas emissions." Thesis, Umeå universitet, Företagsekonomi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185219.

Full text

Abstract:

Sustainability and finance should go hand in hand. A financial system that supports sustainablegrowth is necessary for the transition to a carbon-free society. Environmental, Social andGovernance (ESG) is a sustainability performance measurement used worldwide. Previousresearch within the ESG area has mainly focused on ESG score and financial performance.Environmental performance gets more attention from investors, and the Nordic countries areall in the top five when it comes to sustainability ranking. This research examines the relationbetween sustainability ratings (E score and ESG score) in the Nordic countries as well as if therelation differs between different rating agencies. To study the relationships, a regressionanalysis was performed, and we could not draw any concrete conclusions whether low CO2emissions are associated with a higher E- or ESG score in the Nordic countries. The resultindicates that a high E- or ESG score does not seem to be associated with lower CO2 emissions.A significant result was found on the fact that the E- and ESG scores relation to CO2 aredifferent between rating agencies. However, full access to one of the rating agencies has notbeen granted, which entails some limitations and further research on the questions isrecommended.

APA, Harvard, Vancouver, ISO, and other styles

2

Skantz, Henrik. "Does Cap-and-Trade Reduce Emissions? : Evaluating the Effect of the Regional Greenhouse Gas Initiative on CO2 emissions from the Electrical Power Sector." Thesis, Uppsala universitet, Nationalekonomiska institutionen, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-412173.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Houlihan-Wiberg, Aoif. "An analysis of the performance of certification schemes in the hotel sector in terms of CO2 emissions reduction." Thesis, University of Cambridge, 2010. https://www.repository.cam.ac.uk/handle/1810/226841.

Full text

Abstract:

In assessing the impact of global tourism on climate change, emissions from transport receive the most attention although emissions associated with accommodation account for more than 20% of the total. A plethora of hotel certification schemes have been established worldwide that assess various environmental performance indicators, among them energy use. However, none explicitly quantify CO2 emissions, and in many, energy is poorly accounted for, or other non-energy related factors are weighted so that the overall impact of energy use (and hence CO2 emission) is weak. The main thrust of the research is to ascertain the effect of certification on CO2 emissions. The research questions whether the certification schemes are robust and rigorous and whether the results are credible. First, four widely used certification schemes are compared Nordic Swan (Scandinavia), Green Globe (Worldwide), EU Flower (European) and Green Hospitality Award (Ireland). The key issues are identified such as performance and process related criteria, use of benchmarks, and the weighting of different categories. A comparison is made with LEED-EB, a well-established environmental certification scheme, not dedicated to the hotel sector. Secondly, the way in which emissions from electricity, including so-called green electricity and carbon offsetting, are accounted for is examined since it is found that in obtaining certification, this often plays an important part. Actual annual energy use data is desperately needed as feedback to designers, managers and owners in order to give confidence that certification schemes have true validity. Results are presented from large multi-hotel data samples and for detailed results from the quality, illustrative in-depth studies which provided invaluable insight into the technical realities of a multitude of causes and effects which can often be masked in large data samples. An analysis was carried out for four In-depth studies located in Sweden (Nordic Swan), Maldives (Green Globe), Malta (EU Flower) and Ireland (Green Hospitality Award). Global CO2 emissions were compared and calculated from the delivered electricity and fuels consumption data from seventy selected certified hotels worldwide. No corrections were made in the calculations for climate, quality of services, existence of services etc. The performance indicator used is kgCO2 per guest night. The analyses shows no clear pattern. CO2 emissions show a wide variance in performance for 8 hotels certified under different schemes, as well as for 28 hotels certified under the same scheme. In some cases emissions reduced after certification in others no change. Certified hotels do not necessarily have lower emissions than uncertified hotels and a comparison of before – and after – certification shows no significant improvement prior to certification. Most dramatically emissions from certified hotels widely vary by a factor of 7. Although it is arguable a number of corrections should be made to account for different climates, the research highlights that hotels with high CO2 emissions are being awarded certification and it questions what message‘certification’ gives to guests and other stakeholders. At worst it appears ‘business as usual’ can achieve certification with no obvious improvement in performance. The overall conclusion is that existing certification schemes do not properly account for CO2 emissions and do not produce more energy efficient (or less CO2 intensive) buildings. Hotel accommodation was found to be more CO2 intensive than domestic emissions. The findings also uncovered inconsistencies in current methods of certification and indicate a vital need for improved methods. The results also challenge prevailing aesthetic stereotypes of sustainable hotels. The author concludes a simple CO2 accounting method is needed as the first step of a diagnostic process leading to a solution i.e. reduced emissions, to the problem i.e. high energy consumption and/or emissions, thus reducing the environmental impact (in terms of emissions reduction) of the hotel. This method of accounting can be adopted universally by using a Regional, European (O.475 kgCO2/kWh) or Universal (0.55 kgCO2/kWh) conversion factor. In relation to the proper calculation of energy and CO2 emission, sub-metering is a key factor, and with current technological developments, realistic and affordable. Furthermore, apart from certification itself, an essential quality with any monitoring system is that the user can obtain results easily and understandably, in order to get feedback from their actions. This could be facilitated by incorporating sub-metering as part of the building environmental management system software. This ensures that the certification activity is not simply a benchmark, but is also part of a diagnostic and educational process, which will continue to drive emissions down. Only then should it be ethically justified to use as a marketing tool providing diagnostic support in existing buildings, and design and operational guidance for new designs.

APA, Harvard, Vancouver, ISO, and other styles

4

Quaratino, Marco. "Virtual Calibration of CO2 and Pollutant Emissions of a High-Performance PHEV using Model-in-the-Loop Methodology." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/22053/.

Full text

Abstract:

The study analyses the calibration process of a newly developed high-performance plug-in hybrid electric passenger car powertrain. The complexity of modern powertrains and the more and more restrictive regulations regarding pollutant emissions are the primary challenges for the calibration of a vehicle’s powertrain. In addition, the managers of OEM need to know as earlier as possible if the vehicle under development will meet the target technical features (emission included). This leads to the necessity for advanced calibration methodologies, in order to keep the development of the powertrain robust, time and cost effective. The suggested solution is the virtual calibration, that allows the tuning of control functions of a powertrain before having it built. The aim of this study is to calibrate virtually the hybrid control unit functions in order to optimize the pollutant emissions and the fuel consumption. Starting from the model of the conventional vehicle, the powertrain is then hybridized and integrated with emissions and aftertreatments models. After its validation, the hybrid control unit strategies are optimized using the Model-in-the-Loop testing methodology. The calibration activities will proceed thanks to the implementation of a Hardware-in-the-Loop environment, that will allow to test and calibrate the Engine and Transmission control units effectively, besides in a time and cost saving manner.

APA, Harvard, Vancouver, ISO, and other styles

5

Codruta, Maris Stefania. "Effect of nitrogen fertilization and water management of GHGs (N2O, CO2 and CH4) emissions from intensive Mediterranean agricultural systems." Doctoral thesis, Universitat de Lleida, 2015. http://hdl.handle.net/10803/365310.

Full text

Abstract:

Els gasos amb efecte d'hivernacle (GEH) procedents de l'agricultura depenen de la gestió del reg i dels fertilitzants. L'objectiu d'aquesta tesi va ser identificar les principals estratègies per a mitigar els GEH i obtenir un rendiment màxim: (i) reg continu (CI)/intermitent (II) en un camp d'arròs; (ii) fertilització de fons amb gallinassa (CM), purí porcí (PS), urea (U) o sulfat d'amoni (AS) en un camp d'arròs; (iii) incorporació/eliminació de rostoll de panís amb diferents dosis de N mineral, i (iv) reg enterrat (SDI)/superficial por degoteig (DI) combinat amb N mineral aplicat via fertirrigació amb i sense DMPP en un cultiu súper-intensiu d'olivera. El reg continu minimitza significativament les emissions dels camps d'arròs al mateix temps que garanteix un alt rendiment. L'aplicació de purí porcí en dosis agronòmiques determina alts rendiments i minimitza els GEH. Respecte als GEH i al rendiment del panís, el tractament control va ser la millor opció, independentment de la gestió del rostoll. Així mateix, l'aplicació de DMPP + 50 kg N ha-1 + reg superficial per degoteig (DI) va ser la millor opció pel cultiu d'olivera súper-intensiva
Los emisión de gases con efecto invernadero (GEI) procedentes de la agricultura depende de la gestión del riego y de los fertilizantes. El objetivo de esta tesis fue identificar las mejores estrategias -de entre las siguientes- para mitigar los GEI manteniendo un rendimiento máximo: (i) riego continuo (CI)/intermitente (II) en un arrozal, (ii) la fertilización de fondo con gallinaza (CM) , purín porcino (PS), urea (U) o sulfato amónico (AS) en un arrozal con AS en cobertera, (iii) la incorporación/eliminación del rastrojo con diferentes dosis de N mineral en el cultivo del maíz, (iv) el riego por goteo enterrado (SDI)/superficial (DI) en combinación con N mineral aplicado vía fertirrigación con y sin DMPP en un olivar súper-intensivo. El CI mitiga significativamente las emisiones del arrozal al tiempo que garantiza el rendimiento máximo. La aplicación de purín porcino a dosis agronómicas proporciona altos rendimientos y minimiza los GEI. Considerando las emisiones de GEI y el rendimiento del maíz, el tratamiento control fue la mejor opción, independientemente de la gestión del rastrojo. La aplicación de DMPP + 50 kg N ha-1 + DI fue la mejor opción para el cultivo súper-intensivo de olivo.
Greenhouse gases emissions from agriculture depend on irrigation and fertilisation management. The objective of this thesis was to identify the less emitting management strategies among the following, compatible with a feasible yield: (i) continuous (CI)/intermittent irrigation (II) on rice, (ii) background fertilization with chicken manure (CM), pig slurry (PS), urea (U) or ammonium sulphate (AS) and topdressing on rice, (iii) stover incorporation/removal with different doses of mineral N and, (iv) subsurface (SDI)/surface drip irrigation (DI) in combination with mineral N fertigation with and without DMPP on a super-intensive olive tree orchard. Continuous irrigation significantly mitigated emissions from paddy fields while ensuring the highest yield. Pig slurry application at agronomic doses allowed high yields and minimized emissions. Based on emissions and maize yield, the control treatment was the best option regardless of stover management. Applying DMPP with 50 kg N ha-1+ drip irrigation (DI) was the best option for the olive tree orchard.

APA, Harvard, Vancouver, ISO, and other styles

6

Kwong, Chi Wai. "Effect of co-combustion of coal and biomass on combustion performance and pollutant emissions /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?MECH%202005%20KWONG.

Full text

Abstract:

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005.
"Sponsored by: CLP Research Institute." "HKUST project no.: CLPRI02/03.EG01." Includes bibliographical references (leaves 76-83). Also available in electronic version.

APA, Harvard, Vancouver, ISO, and other styles

7

Al-Asadi, Akram A. "Iron Carbide Development and its Effect on Inhibitor Performance." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1416422709.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Keidel, Lisa [Verfasser]. "The effect of elevated CO2 on soil C and N dynamics and its feedback on CO2 and N2O emissions from a temperate grassland ecosystem : results from a long-term Free Air CO2 Enrichment (FACE) experiment / Lisa Keidel." Gießen : Universitätsbibliothek, 2019. http://d-nb.info/1198674083/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Smart, John Philip. "On the effect of burner scale and coal quality on low NOâ†x burner performance." Thesis, University of London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262555.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Mian, Muhammad Masoud. "Green Packaging Development. : A way to efficient, effective and more environmental friendly packaging solutions." Thesis, KTH, Hållfasthetslära (Inst.), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103749.

Full text

Abstract:

Growing pressure on the packaging design to enhance the environmental and logistics performance of a packaging system stresses the packaging designers to search new design strategies that not only fulfill logistics requirements in the supply chain, but also reduce the CO 2emissions during the packaging life cycle. This thesis focuses on the packaging design process and suggests some improvements by considering its logistics performance and CO 2emissions. A Green packaging development model was proposed for corrugated box design to explore the inter-dependencies that exist among compressive strength, waste and CO2emissions. The verification of the proposed model unveils the significance of a holistic view of the packaging system in the packaging design process and reveals the importance of packaging design decisions on the logistics performance and CO 2 emissions. The thesis finally concluded that the packaging logistics performance should be considered in a packaging design process to explore the Green packaging design solution.

APA, Harvard, Vancouver, ISO, and other styles

11

Summerbell, Daniel Leo. "Environmental performance improvement in the cement industry." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/275450.

Full text

Abstract:

This research investigates ways to reduce the carbon dioxide emissions from the cement industry. Cement is one of the largest sources of man-made greenhouse gases, contributing ~5% of the global total. 40% of emissions from cement come from the fuel used in the process, while the electricity used contributes a further 5%. The focus of the research is to find operational changes that can reduce emissions without the need for large capital investment. Three cement plants in the UK were investigated using four different mathematical models based on real data from the plants. A new metric for assessing the environmental impact of the fuel mix of a plant was proposed, and evidence indicates that it may be a better predictor of environmental performance than the metrics currently used in industry. The research found that consistently improving this fuel metric to best-observed levels, as well as reducing the excess air ratio to industry-standard levels had the potential to reduce fuel consumption by up to 7%, and fuel derived CO2 emissions by up to 12%. Increasing use of biomass to best-observed levels had the potential to reduce the net fuel derived CO2 emissions by up to 20%. Comparing the proposed improvements to the historic range of plant performance showed that this level of performance is within the normal operating range of the plants. A reduction of 2-4% in electricity costs and electricity derived emissions was also possible from operational changes. These savings would reduce operating costs as well as emissions, and require little to no capital investment, meaning they could be implemented directly. If successfully implemented in the near future the total savings by 2050 would be on a similar scale to those expected from much more expensive technology changes, such as upgrading to new cement plants, or installing carbon capture and storage technology.

APA, Harvard, Vancouver, ISO, and other styles

12

Alger, Terrence Francis. "Factors in charge preparation and their effect on performance and emissions from a direct injection spark ignition engine." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3023542.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Meurisse, Bénédicte. "Politiques économiques publiques pour limiter les émissions de CO2 liées à l’usage des véhicules particuliers." Thesis, Paris 10, 2015. http://www.theses.fr/2015PA100137/document.

Full text

Abstract:

Cette thèse porte sur les instruments de politique publique permettant de réduire les émissions de CO2 liées à l’usage des véhicules particuliers. La mise en place de ces instruments est légitime et nécessaire compte tenu de la contribution de ces véhicules au changement climatique (17% des émissions de CO2 en France en 2010). Dans le cadre d’une modélisation théorique en équilibre partiel et statique du marché automobile, les travaux considèrent deux leviers de réduction d’émissions : l’amélioration de la performance énergétique des véhicules et la diminution des distances parcourues. Dans un premier Chapitre consacré à l’analyse côté offre du système automobile, la question de recherche est de déterminer si, d’une part, une coopération entre acteurs de la filière automobile conduit à la production de véhicules plus économes en carburant qu’en l’absence de coopération, et d’autre part, si cette coopération est un substitut ou non à l’intervention publique. L’impact de la demande de véhicules économes en carburant sur les décisions d’investissement et de coopération des producteurs est démontré, ce qui justifie la mise en place d'outils de politique publique stimulant la demande. Aussi, le deuxième Chapitre est consacré à l’analyse de la demande de véhicules et de kilomètres. L’accent est mis sur l’interdépendance entre ces deux demandes, qui est à l’origine du phénomène bien connu d’effet rebond. Il est question d’étudier l’impact de cet effet rebond sur l’efficacité des taxes différenciées à l’achat et des taxes à l’usage des véhicules. Enfin, l’ambition du dernier Chapitre est tenir compte des effets de ces instruments sur l’utilité des ménages et le profit pour la filière automobile. L’objectif plus large est de déterminer si les décideurs publiques sont à mêmes de lutter contre les émissions de CO2 des véhicules tout en augmentant le bien-être de la population et la croissance économique
This Thesis analyses public economic policies enabling to reduce CO2 emissions from car use. Implementing these tools is legitimate and necessary because of the high contribution of passenger vehicles to climate change (17% of CO2 emissions in France in 2010). Within a partial and static equilibrium model of the car market, the present research considers two distinct levers to cut CO2 emissions from car use: the improvements of passenger vehicles energy-efficiency, and a reduction in miles driven. In the first Chapter dedicated to an analysis of the supply-side of the automotive system, the research question consists in investigating on the one hand whether a cooperation among actors of the automotive sector leads to the production of vehicles that are less fuel-consuming than without the cooperation; and on the other hand whether this cooperation could be a substitute to a policy intervention. The impact of the demand for low fuel-consuming vehicles on the producers’ decision to invest and to cooperate is demonstrated; this justifies the implementation of policy tools stimulating demand. Hence, the second Chapter is dedicated to an analysis of the demand for vehicles and kilometres. Emphasis is placed on the interdependency between car choice and car use, which is at the root of the well-known phenomenon of rebound effect. The aim is to study the impact of that rebound effect on the efficiency of differentiated car purchase taxes and car use taxes. Lastly, the ambition of the last Chapter is to take the impacts of the latter pricing tools on households’ utility and automotive sector’s profit into account. More generally, the purpose is to investigate whether public decision-makers are able to mitigate CO2 emissions from car use while improving households’ well-being and economic growth

APA, Harvard, Vancouver, ISO, and other styles

14

Flett, Matthew Alexander. "Subsurface re-injection of carbon dioxide for greenhouse gas control: influence of formation heterogeneity on reservoir performance." Curtin University of Technology, Dept. of Petroleum Engineering, 2008. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=18597.

Full text

Abstract:

The injection of carbon dioxide (CO2) into saline formations for the purpose of limiting greenhouse gas emissions has been proposed as an alternative to the atmospheric venting of carbon dioxide. In the evaluation process for selecting a potential target saline formation for the disposal of carbon dioxide, flow characterisation of the disposed plume should be undertaken by reservoir simulation of the target formation. The movement of injected carbon dioxide in the saline formation is influenced by many factors including the physics of carbon dioxide at deep formation depths and pressure, physical interactions with formation rock and pore water and variations in the rock flow pathways through changes in formation heterogeneity. This thesis investigates the roles of physical interactions on the disposal of carbon dioxide and the ability to contain the injected gas through evaluation of trapping mechanisms such as dissolution of CO2 in formation water and residual gas trapping through the process of gas-water relative permeability hysteresis. Variable formation heterogeneity is evaluated for its impact on the migration of injected CO2 plume movement and the role of formation heterogeneity in impeding or accelerating the immobilisation of injected carbon dioxide. Multiple reservoir simulation studies were conducted to evaluate, initially, the role of different trapping mechanisms in immobilising the movement of injected carbon dioxide and subsequently, the role of variations in formation rock in the migration and trapping of and injected plume of carbon dioxide. The major simulation study shows that the selection process for identifying appropriate saline formations should not only consider their size and permeability but should also consider their degree of heterogeneity endemic to the formation.
A set of reservoir performance metrics were developed for the CO2 disposal projects. The metrics were applied to compare plume migration of injected CO2 (both vertically and laterally) and containment (through dissolution and residual phase trapping) in these studies. The findings demonstrate how formation heterogeneity has a significant impact on the subsurface behaviour of the carbon dioxide. Formation dip influences the rate of migration, with low formation dipping reservoirs having slower rates of vertical migration. Increasing the tortuousity of the migration flow path by either increasing the shale (non-reservoir) content or lengthening the shale baffles in the formation (corresponding to a gradual decrease in reservoir quality), can progressively inhibit the vertical flow of the plume whilst promoting its lateral flow. The increase in the tortuosity of the CO2 migration pathway delays the migration of CO2 and increases the residence time for the CO2 in the formation. Thus, formation heterogeneity impedes the onset of residual gas trapping through hysteresis effects. Ultimately less carbon dioxide is likely to collect under the seal in heterogeneous formations due to increased reservoir contact and long residence times, thereby reducing the risk of seepage to overlying formations.
Given sufficient permeability for economic injection of CO2, then low to mid net-to-gross heterogeneous saline formations with low formation dip and lengthy intra-bedded shales are desirable for selection for the geological disposal of CO2. Detailed reservoir characterisation of any potential geological disposal saline formations is required in order to accurately predict the range of outcomes in the long term flow characterisation of injected CO2 into those formations.

APA, Harvard, Vancouver, ISO, and other styles

15

Holmes, Jacklyn (Jacklyn A. ). "The effect of carburetor refurbishing on emissions, performance, and fuel economy in a classic pickup tested using real-world tests." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/69179.

Full text

Abstract:

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 28).
This project investigated how refurbishing the carburetor of a 1952 Chevrolet Pickup would affect emissions, performance, and fuel economy. The test used were real-world tests that anyone, with or without access to a laboratory, can perform. The design of the real-world tests is important for ascertaining good results. Thought should go into how to perform the tests safely while still eliminating as many variables as possible. The emissions at idle improved by reducing the carbon monoxide percentage from 4-6% to 2- 3%. The hydrocarbon levels were reduced from 800-1000 ppm to 500-600 ppm. The results of the emissions test were unclear at cruise. The performance data showed that the vehicle had a slower acceleration after the refurbishing. The time to go from stopped to 100 feet in first gear was 5.46 s before refurbishing, and 6.48 s after refurbishing. It is possible that the vehicle was running lean at wide-open throttle after refurbishing. The fuel economy improved with the refurbished carburetor. The initial fuel economy was 10.7 mpg and the final fuel economy was 15.2 mpg. Once the results from the tests are collected, they need to be scrutinized to see if they are plausible using empirical data. Even with extreme care it is difficult to get precise measurements using real-world tests. The emissions data at cruise was not consistent with idle and could not be used. The fuel economy tests and emissions tests at idle show that the engine was running less fuel rich after refurbishing.
by Jacklyn Holmes.
S.B.

APA, Harvard, Vancouver, ISO, and other styles

16

Attard, William. "Small engine performance limits - turbocharging, combustion or design." SAE Technical Paper Series, 2007. http://repository.unimelb.edu.au/10187/514.

Full text

Abstract:

Growing concerns about interruption to oil supply and oil shortages have led to escalating global oil prices. In addition, increased public acceptance of the global warming problem has prompted car manufacturers to agree to carbon emission targets in many regions including most recently, the Californian standards. Other legislating bodies are sure to follow this lead with increasingly stringent targets. As a result of these issues, spark ignition engines in their current form will need significant improvements to meet future requirements. One technically feasible option is smaller capacity downsized engines with enhanced power that could be used in the near term to reduce both carbon emissions and fuel consumption in passenger vehicles.This research focuses on exploring the performance limits of a 0.43 liter spark ignited engine and defining its operating boundaries. Limiting factors such as combustion, gas exchange and component design are investigated to determine if they restrict small engine performance. The research gives direction to the development of smaller gasoline engines and establishes the extent to which they can contribute to future powertrain fuel consumption reduction whilst maintaining engine power at European intermediate class requirements.

APA, Harvard, Vancouver, ISO, and other styles

17

Canto, Maya Christian M. "Effect of Wall Shear Stress on Corrosion Inhibitor Film Performance." Ohio University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1447954894.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Eriksson, Viktor. "Design of Ultra High Performance Fibre Reinforced Concrete Bridges : A Comparative Study to Conventional Concrete Bridges." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-75183.

Full text

Abstract:

The use of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) in the construction industry started in the 1990s and has since then been used for bridges all over the world. The mechanical properties and the dense matrix result in lower material usage and superior durability compared to conventional concrete, but the implementation of UHPFRC in the Swedish industry has been delayed. The most evident explanation, based on interview with industry representatives, as to why UHPFRC is not commonly used in Sweden are due to the lack of standards and knowledge. UHPFRC also has a high cement content and the cement industry contributes with high carbon dioxide (CO2) emissions to the total CO2 emissions in the world. This MSc Thesis looks into if a UHPFRC bridge is a feasible alternative to a conventional reinforced concrete structure bridge from design and material usage perspectives, regarding reduction of CO2 emissions. The project’s overall goal is to increase the knowledge in Sweden about the material, regarding the production, mechanical properties and behaviour of UHPFRC, and the design, regarding the difference in design between UHPFRC and conventional concrete bridges. To examine the material, a UHPFRC mixture with short straight steel fibres was developed. Specimens were tested to see how the different fibre contents affect the mechanical properties and which fibre content that is most favourable. Three different fibre contents were tested: 1.5%, 2.0% and 2.5% of the total volume of the mixture. The tested and evaluated mechanical properties were workability, flexural strength, tensile strength, fracture energy, compressive strength and modulus of elasticity. This study does not contain tests of durability of UHPFRC, however trough the literature review it was investigated to what extent the fibres affect the durability. It was concluded that an increase in fibre content results in improved mechanical properties, except for workability and in some cases when using a fibre content of 2.5%. The increase in the mechanical properties is due to the increased cracking resistance and the bond strength between the fibres and the matrix. The decrease in the mechanical properties, e.g. characteristic tensile strength and compressive strength of cylinders, for 2.5% in fibre content can be due to uneven fibre distribution and higher amount of air in the specimens which result in less strength. It was concluded that 2.0% in fibre content is most favourable. It was possible to conclude that the degradation of the fibres takes a long time, however not to what extent the fibres will affect the durability. To evaluate if UHPFRC is a viable economical and environmental alternative to regular concrete bridges, three cases of bridge design are considered. Two cases with UHPFRC (different thickness) and one case with conventional concrete. Up to 2017 only technical guidelines and recommendations for design with UHPFRC existed, but in 2017 the first approved standards in the world were published. The French national standards cover material (NF P18-470, 2016) and design (NF P18-710, 2016) and were used for the design process. The material usage regarding the amount of reinforced UHPFRC/concrete and steel reinforcement as well as the amount of CO2 emissions from the production of cement and steel (fibre and steel reinforcement) used for the bridges in the mid-span and at the support were investigated. The design process was also evaluated. It was concluded that the UHPFRC bridge with an optimized thickness was 47% lighter than the conventional concrete bridge, but the amount of CO2 emissions was still higher (e.g. 23% from the support). To be able to determine if a UHPFRC bridge is a feasible alternative to a conventional concrete bridge, with regards to the reduction of CO2 emissions, the CO2 emissions have to be observed in a wider perspective than only from the production of cement and steel, e.g. fewer transports and longer lifetime.
Användningen av ultrahögpresterande fiberbetong (UHPFRC) i anläggningsindustrin började på 1990-talet och har sedan dess använts till broar i hela världen. De mekaniska egenskaperna och den täta UHPFRC matrisen resulterar i lägre materialanvändning och bättre beständighet i jämförelse med konventionell betong, men användningen av UHPFRC har inte slagit igenom i den svenska industrin. De största förklaringarna till varför UHPFRC sällan används i Sverige är för att det inte har funnits kunskap och standarder. UHPFRC har också en hög cementhalt och cementindustrin bidrar med höga koldioxid (CO2) utsläpp till de totala CO2 utsläppen i världen. Den här masteruppsatsen skrevs för att undersöka om en UHPFRC bro är ett möjligt alternativ till en konventionell betongbro ur dimensionering- och materialanvändningssynpunkt med avseende på reduktion av CO2 utsläpp. Projektets övergripande mål är att öka kunskapen om materialet, med avseende på tillverkningen, de mekaniska egenskaperna och beteendet av UHPFRC, och dimensionering, med avseende på skillnaden i dimensionering mellan UHPFRC broar och konventionella betongbroar. I materialdelen utvecklades ett UHPFRC recept med korta raka stålfibrer. Provkroppar testades för att se hur olika fiberinnehåll påverkade de mekaniska egenskaperna och vilket fiberinnehåll som var mest gynnsamt. Tre olika fiberinnehåll testades: 1.5%, 2.0% och 2.5% av total volym av blandningen. De mekaniska egenskaperna som testades och utvärderades var bearbetbarheten, böjhållfasthet, draghållfasthet, fraktur energi, tryckhållfasthet och elasticitetsmodul. Beständigheten av UHPFRC testades aldrig men i vilken omfattning fibrerna påverkar beständigheten undersöktes i den litteraturstudie som skrevs inför testerna och tillverkningen av UHPFRC. Det konstaterades att en ökning i fiberinnehåll resulterade i en ökning av de mekaniska egenskaperna, förutom för bearbetbarheten och i vissa fall när ett fiberinnehåll av 2.5% användes. Ökningen av de mekaniska egenskaperna berodde på det ökande sprickmotståndet och bindningsstyrka mellan fibrerna och matrisen. Minskningen av de mekaniska egenskaperna, till exempel den karakteristiska drag- och tryckhållfastheten, när ett fiberinnehåll på 2.5% i cylindrar användes kan bero på ojämn fiberfördelning och större mängd luft i provkropparna vilket resulterar i lägre hållfasthet. Det konstaterades att ett fiberinnehåll på 2.0% var det mest gynnsamma. Det kunde inte konstateras i vilken omfattning fibrerna påverkar beständigheten men det kunde konstateras att nedbrytningen av fibrerna tar lång tid. I dimensioneringsdelen utformades tre slakarmerade balkbroöverbyggnader, i två fall var överbyggnaden med UHPFRC (olika tjocklekar) och i ett fall var den med konventionell betong. Fram till 2017 fanns det bara tekniska riktlinjer och rekommendationer för UHPFRC men 2017 publicerades de första godkända standarderna i världen. De franska nationella standarderna täcker material (NF P18-470, 2016) och dimensionering (NF P18-710, 2016) och användes vid dimensioneringen. Materialanvändningen med avseende på mängd armerad UHPFRC/betong och slakarmering och mängd CO2 utsläpp från produktionen av cement och stål (fibrer och slakarmering) som användes till broarna i mittenspannet och vid stöden undersöktes. Även dimensioneringsprocessen utvärderades. Det konstaterades att UHPFRC bron med optimerad tjocklek var 47% lättare än betongbron men mängden CO2 utsläpp var fortfarande högre (till exempel 23% högre från stödet). Det konstaterades att om det ska vara möjligt att fastställa att en UHPFRC bro är ett möjligt alternativ till en konventionell betongbro, med avseende på reduktion av CO2 utsläpp, måste CO2 utsläppen ses från ett bredare perspektiv än från bara produktion av cement och stål, till exempel mindre transporter och längre livslängd.

APA, Harvard, Vancouver, ISO, and other styles

19

Phan, Le Quynh Nhu. "PIM-1/ ZIF-8 MIXED MATRIX MEMBRANE FOR CO2/ CH4 SEPARATION : Investigating the effect of ZIF-8 particle size on separation performance." Thesis, Umeå universitet, Kemiska institutionen, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-176672.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Murray, Cameron Keith. "New insights into rebound effects : theory and empirical evidence." Queensland University of Technology, 2009. http://eprints.qut.edu.au/27655/.

Full text

Abstract:

The main objective of the thesis is to seek insights into the theory, and provide empirical evidence of rebound effects. Rebound effects reduce the environmental benefits of environmental policies and household behaviour changes. In particular, win-win demand side measures, in the form of energy efficiency and household consumption pattern changes, are seen as ways for households and businesses to save money and the environment. However, these savings have environmental impacts when spent, which are known as rebound effects. This is an area that has been widely neglected by policy makers. This work extends the rebound effect literature in three important ways, (1) it incorporates the potential for variation of rebound effects with household income level, (2) it enables the isolation of direct and indirect effects for cases of energy efficient technology adoption, and examines the relationship between these two component effects, and (3) it expands the scope of rebound effect analysis to include government taxes and subsidies. MACROBUTTON HTMLDirect Using a case study approach it is found that the rebound effect from household consumption pattern changes targeted at electricity is between 5 and 10%. For consumption pattern changes with reduced vehicle fuel use, the rebound effect is in the order of 20 to 30%. Higher income households in general are found to have a lower total rebound effect; however the indirect effect becomes relatively more significant at higher household income levels. In the win-lose case of domestic photovoltaic electricity generation, it is demonstrated that negative rebound effects can occur, which can potentially amplify the environmental benefits of this action. The rebound effect from a carbon tax, which occurs due to the re-spending of raised revenues, was found to be in the range of 11-32%. Taxes and transfers between households of different income levels also have environmental implications. For example, a more progressive tax structure, with increased low income welfare payments is likely to increase greenhouse gas emissions. Subsidies aimed at encouraging environmentally friendly consumption habits are also subject to rebound effects, as they constitute a substitution of government expenditure for household expenditure. For policy makers, these findings point to the need to incorporate rebound effects in the environmental policy evaluation process.’

APA, Harvard, Vancouver, ISO, and other styles

21

Noutary, Marie-Pierre. "A robust Reynolds solver for textured surfaces in the piston ring cylinder liner contact." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI105/document.

Full text

Abstract:

Le contact Segment-Piston-Chemise (SPC) est essentiel pour la réduction des émissions de CO2 et de polluants dans les moteurs automobile. Pour optimiser ces deux contraintes antagonistes, il est nécessaire d’étudier l’influence de la microgéométrie afin de trouver de nouvelles architectures de ce contact. L’étude expérimentale étant très coûteuse, il est impératif de pouvoir modéliser les performances du contact SPC. Les méthodes multigrilles permettent de réduire considérablement les temps de calcul. Pour le contact SPC, les méthodes multigrilles classiques perdent leur efficacité en présence de texture. Un nouvel algorithme, basé sur des idées développées par Alcouffe et al. a été conçu qui permet l’étude du contact hydrodynamique en présence de texturation importante. Il a été validé par comparaison avec un modèle analytique 1D, ses performances ont été étudiées et une première étude de l’influence des paramètres sur la portance pour une surface striée a été faite. L’algorithme a ensuite été modifié pour imposer la conservation des flux. Un processus de relaxation plus proche de la physique du phénomène est utilisé. Le code obtenu n’atteint pas l’efficacité multigrille optimale. Cependant sa convergence est suffisamment rapide pour étudier l’influence de pores pour le segment plat et montrer l’importance d’une texturation partielle. Pour finir, le terme transitoire de l’équation de Reynolds est pris en compte. Pour un segment parabolique et une chemise striée, l’influence des paramètres des stries (profondeur, largeur, distance et angle des stries) sur la variation moyenne de la hauteur de film par rapport à une surface lisse est analysée
The piston ring cylinder liner (PRCL) contact is essential in the CO2 and pollutant emission reduction in internal combustion engine. These two constraints being antagonistic, a compromise has to be found and it is necessary to study the microgeometry influence in order to find new PRCL contact architectures. As experimental study can be very expensive, modeling PRCL contact performance becomes crucial. Multigrid methods allow a huge reduction of the computational time. Unfortunately, in presence of texture, classical multigrid efficiency decays significantly and are not usable. A new algorithm based on an approach developed by Alcouffe et al. was designed that allows the study of the hydrodynamic lubrication of this contact even in the case of a highly varying geometry due to the texture. The obtained code was validated by comparison with a 1D analytical model, its performance was evaluated and a first study of an analytic cross hatched geometry parameter influence on the load carrying capacity was completed. The code was modified to include flow conservation. A relaxation process based closer to the physics phenomenon is used. The code efficiency is not the one that is expected from multigrid technics. However it convergence is sufficiently fast to study the dimple influence for the oil control ring and show the importance of partial texturing. Finally the transient term of the Reynolds equation is accounted for. In the case of a parabolic ring and for a cross hatched liner, the influence of the groove parameters ( depth, width, distance and groove angle) on the average minimum film thickness with respect to the smooth case is analyzed

APA, Harvard, Vancouver, ISO, and other styles

22

Horikx, Lotte, and Bledar Beqiri. "Circular economy in the Nordic region – on the right path? : The effect of circular economy business practices on firms’ environmental performance." Thesis, Uppsala universitet, Företagsekonomiska institutionen, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-324860.

Full text

Abstract:

Over the last couple of decades, sustainability has gained importance in the business world, and a concept that has often been used as a prime example of how to deal with today’s environmental problems is circular economy. Even though the topic is relatively new, there has already been quite some debate about its actual advantages and disadvantages, and while there is as of yet no consensus, the majority argues that the application of circular economy practices will be beneficial for the environment. Which is exactly what this research has attempted to ascertain by looking at 78 firms from a wide range of industries yet all from the Nordic region, since this geographical area has been hailed repeatedly for their sustainability. This was done by performing a hierarchical regression analysis on the data in order to explore a possible relationship between the score of a firm on the benchmark of circular economy practices and its corresponding environmental performance, specifically energy consumption, water usage and greenhouse gas emissions. The hierarchical regression analysis showed a significantly positive relationship between a firm’s score on the benchmark of circular economy practices and its energy consumption, while controlling for firm size, industry, debt ratio,slack resources and country of origin, which was contrary to expectations. No such relationship was found between a firm’s benchmark score and their water usage, the same goes for greenhouse gas emissions. Nevertheless, this research has taken an important step in understanding the relationship between circular economy practices and a firm’s environmental performance, and in doing so has opened up new avenues to explore in terms of future research. While the Nordic region is on the right track, there is still a long road ahead.

APA, Harvard, Vancouver, ISO, and other styles

23

Akchiche, Meziane. "Analyse exergétique et Optimisation dynamique des systèmes de production d’hydrocarbures dans la perspective de réduire les émissions de CO2." Thesis, Pau, 2020. http://www.theses.fr/2020PAUU3031.

Full text

Abstract:

Ce projet de recherche s’inscrit dans une démarche d’amélioration de l’efficacité énergétique et de la réduction des émissions de gaz à effet de serre des systèmes de production de pétrole et de gaz au sein du groupe Total.L’analyse exergétique a été développée et appliquée pour la première fois à la partie subsurface (réservoir-puits) et élargie pour l’ensemble du système de production de pétrole et de gaz, permettant de quantifier les différentes pertes et destructions d’exergie, l’exergie naturelle fournie par le réservoir et l’exergie générée artificiellement (activation), pour des exemples théoriques et réels. Nous avons aussi proposé une représentation avec des diagrammes de Grassmann adaptés pour afficher les résultats de l’analyse exergétique sur l’ensemble du système de production. Enfin, les résultats de l’analyse exergétique nous ont permis de proposer des solutions technologiques pour améliorer la productivité et réduire les émissions de CO2.Dans la deuxième partie de ce projet nous avons développé une nouvelle méthodologie pour l’optimisation dynamique des systèmes de production d’hydrocarbures dans l’environnement contraint des logiciels dédiés à la production pétrolière (en l’occurrence dans cette thèse la suite IPM (Integrated Production Modeling) développée par PETEX). L’objectif est de proposer une optimisation simultanée de la structure et des paramètres opératoires du système de production (écoulement naturel ou assisté? quel type d’activation: gas-lift, pompes? quel type de pompe?) tout le long de la vie du champ. Deux fonctions objectif sont proposées pour évaluer la performance des systèmes de production d’hydrocarbures pendant tous leurs cycles de vie : i) l’exergie nette cumulée (CNE) et ii) profit cumulé (CNP). Le problème énoncé est ensuite résolu à l'aide de la suite IPM de PETEX, couplée au calculateur thermodynamique Simulis® Thermodynamics (PROSIM) pour les calculs exergétiques. L’approche est une approche séquentielle et les pas horaires sont de l’ordre de l’année, chaque pas horaire étant simulé en quasi-statique. L'algorithme génétique inclus dans la suite IPM est utilisé pour résoudre le problème d’optimisation dynamique en variables mixtes moyennant quelques adaptations. Les résultats montrent qu’il est possible de trouver un compromis entre la rentabilité et les émissions de gaz à effet de serre (GES)
This research project is part of an initiative to improve the energy efficiency and reduce greenhouse gas emissions of oil and gas production systems within the Total Group. Exergy analysis has been developed and applied for the first time to the subsurface part (reservoir-well) and extended to the entire oil and gas production system, making it possible to quantify the different losses and destruction of exergy, the natural exergy provided by the reservoir ,and the artificially generated exergy (artificial lift and boosting), for theoretical and real examples. We have also proposed a representation with adapted Grassmann diagrams to display the results of the exergy analysis on the whole production system. Finally, the results of the exergy analysis allowed us to propose technological solutions to improve hydrocarbon production and reduce greenhouse gas (GHG) emissions.In the second part of this project we developed a new methodology for the dynamic optimization of hydrocarbon production systems in a constrained software environment dedicated to petroleum production (in this case the IPM (Integrated Production Modeling) solution developed by PETEX). The objective is to propose a simultaneous optimization of the structure and operating parameters of the production system (natural or artificial ? what type of artificial lift and/or boosting system : gas-lift, pumps? Which type of pumps?) throughout its life cycle. Two objective functions are proposed to evaluate the performance of hydrocarbon production systems: (i) cumulative net exergy (CNE) and (ii) cumulative net profit (CNP). The stated problem is then solved using PETEX's IPM suite, coupled with the Simulis® Thermodynamics Calculator (PROSIM) for exergy calculations. The approach is sequential and the time-steps are in the order of a year, each time-step being simulated in quasi-static. The genetic algorithm included in the IPM suite is used to solve the mixed variables dynamic optimization problem with some adaptations. The results show that it is possible to find a compromise between profitability and greenhouse gas (GHG) emissions

APA, Harvard, Vancouver, ISO, and other styles

24

Faramarzi, Ghazal, and Malin Torestam. "Development of evaluation tools as an approach to pre-design district energy systems : Qualitative modeling and performance simulation using OpenModelica." Thesis, KTH, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-288104.

Full text

Abstract:

Cities and districts contribute to a large fraction of the total energy consumption in Sweden. The residential- and service sector accounted for almost 40% of the total energy consumption in 2018. The increasing urbanization also puts more importance on the energy supply, distribution and consumption in these areas. One way of planning an energy system in urban areas is to have integrated energy systems where synergies between different technologies and energy carriers are utilized. Such a solution can increase the flexibility of the energy system and thus help integrate more intermittent renewable energy sources. The aim of this study was to suggest tools for planning energy systems in districts. This was done by performing a literature review regarding the design of energy systems and the identification of barriers and opportunities for the integration of different production- and distribution technologies. The focus was on systems for heating, cooling and electricity. The proposed tools are three Excel-based modules. The first module is a qualitative model that presents the reviewed technologies and their connections. It also includes synergies between different energy carriers and sectors for consumption and production. The second module is qualitative model related to market mechanisms, juridical, organizational and institutional aspects. The third module is a table containing the barriers and opportunities. Furthermore, relevant stakeholders are identified to be district heating companies, building owners, joint associations, municipalities, district cooling companies and photovoltaic plant owners. The proposed tools can be used in the first stage of planning when the technologies are selected. To show how the suggested tools can be applied, a case study was performed. The study case is a district being planned in Stockholm, Sweden. For the analysis, a model for a hypothetical heating system was required. Two models were developed for the heat supply system using the modelling environment OpenModelica. The main objective of the case study was to compare the techno-economic and environmental performance of different scenarios. Three different scenarios were considered for covering the total heating demand in the district. In the first scenario the total heating demand is covered only by local heat pumps. In the second scenario the space heating demand is covered by heat pump(s) coupled with a thermal energy storage (hot water tank). An electric boiler is used as backup. In the third scenario, the electric boiler is replaced by district heating as backup. A sensitivity analysis was included for different numbers of heat pumps and different sizes of thermal energy storage in the two last scenarios. The economic and environmental results in this study were strongly dependent on the assumptions regarding prices and emission factors. The result of the case study indicates that the third scenario causes the lowest CO2 emissions. An increased size of the thermal energy storage causes a higher compressor electricity consumption thus more emissions. However the total emissions from the system depends on the backup component. For this result, the emission factor related to Swedish electricity mix and the emission factor stated by a district heating company in Stockholm was used. The cheapest alternative in terms of annual operational cost of energy is the first scenario with only heat pumps. However, from the scenarios which also includes thermal energy storage, the second scenario with three heat pumps and a 100 m3 large thermal energy storage, presents the lowest cost. This system design in scenario 2 is only 0.6% more expensive than the first scenario. For the energy prices, the assumption for electricity is based on hourly values from Nordpol and for heat, the values presented in a normal price list from a district heating company is assumed. Regarding the technical performance of the system the result indicates that the contribution from the thermal energy storage as it is modelled in this case study is not significant on anannual basis. However it is observed that a larger thermal energy storage unit covers a higher fraction of the power demand during the hours it is utilized.
Städer och stadsdelar står för en stor del av totala energikonsumtionen i Sverige. Bostads- och servicesektor stod för ungefär 40% av totala energikonsumtionen under 2018. Den ökande urbaniseringen lägger också mer vikt vid energiproduktion, distribution och konsumtionen i dessa områden. Ett alternativ för planering av energisystem i urbana områden är att ha integrerade energisystem där synergier mellan olika teknologier och energibärare kan utnyttjas. Den typen av system skulle kunna öka flexibiliteten i energisystemet och därför förenkla integrering av oförutsägbara förnybara energikällor. Syftet med denna studie var att föreslå verktyg för planering av energisystem i stadsdelar. Detta gjordes genom en litteraturstudie angående utformningen av olika energisystem samt identifiera hinder och möjligheter för att integrera olika produktions- och distributions teknologier. Fokus låg på systemen för värme, kyla och elektricitet. Det föreslagna verktygen är tre Excel baserade moduler. Den första modulen är en qualitative modell som presenterar de studerade teknologier och deras kopplingar. Den innehåller också synergier mellan de olika energibärarna och konsumtions- och produktionssektorn. Den andra modulen är en qualitative modell, men relaterad till marknad mekanismer, juridiska, organisatoriska och institutionella aspekter. Den tredje modulen är en tabell som beskriver hinder och möjligheter för några av teknologierna. Utöver det de relevanta aktörerna identifierades. För värme-, kyla- och elektricitet marknaden är de fjärrvärmeföretagen, fastighetsägare, samfälligheter, kommuner, fjärrkyla företagen, solcells ägare. De föreslagna verktyget kan användas för planering av energisystem i ett första skede när teknologier ska väljas. En fallstudie genomfördes för att visa hur det föreslagna verktyget kan användas. Fallstudien en stadsdel som planeras i Stockholm, Sverige. För att genomföra en analys behövdes en modell för ett hypotetiskt värmesystem. Två modeller utvecklades för värmesystemet genom att använda modelleringsmiljön OpenModelica. Det huvudsakliga målet med fallstudien var att jämföra den teknoekonomiska- och miljöinriktade prestandan för olika scenarierna. Tre olika scenarier övervägdes för att täcka totala värmebehovet i stadsdelen. I det första scenariot täcks det totala värmebehovet endast av lokala värmepumpar. I andra scenariot täcks värmebehovet för uppvärmning av värmepump(ar) kopplade till en värmelagrings komponent (ackumulatortank). En elpanna användes för reserveffekt. I tredje scenariot är elpannan ersatt av fjärrvärme. En känslighetsanalys var utförd för olika antal värmepumpar kopplade till olika storlekar av värmelagrings-komponenten i de två sista scenarierna. De ekonomiska och miljörelaterade resultatet i den här studien är starkt beroende av antaganden gällande priser och utsläppsfaktorer. Resultatet indikerar att det tredje scenariot har de lägsta CO2 utsläppen. Ökad värmelagringsstorlek bidrar till att värmepumpen förbrukar mer elektricitet och därför ökar de relaterade utsläppen. Däremot beror de totala utsläppen i systemet på vilken reservkraft som används. För dessa resultat användes utsläppsfaktorn för svensk elmix samt utsläppsfaktorn från ett fjärrvärme företag i Stockholm. Den billigaste alternativet gällande årlig driftsenergikostnad är det första scenariot med endast värmepumpar. Däremot, bland de scenarion som innehåller värmelagring, har det andra scenariot med tre värmepumpar och 100m3 stor värmelagringsenhet den lägsta kostnaden. Detta system är endast 0.6% dyrare än det första scenariot. För energipriser har timvärden från Nordpol antagits för elektricitet och för värme har normalprislistan från ett fjärrvärmebolag i Stockholm antagits. Angående den tekniska systemprestandan, indikerar resultatet att bidraget från värmelagringsenheten som den är modellerad i den här fallstudien inte är signifikant på årsbasis. Det observeras emellertid att en större värmelagringsenhet täcker en större andel av effektbehovet under de timmar som enheten används.

APA, Harvard, Vancouver, ISO, and other styles

25

Feizaghaei, Roozbeh. "Improving climate performance of cement production : Developing an assessment framework and applying it to a CEMEX cement production cluster in Germany." Thesis, Linköpings universitet, Industriell miljöteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-73643.

Full text

Abstract:

It is very likely that human being is contributing to the process of global warming. Industrial activities such as cement production are among the largest sources of human-induced greenhouse gas emissions. Therefore, there are ongoing efforts to reduce the CO2 emissions attributed to the cement production. In order to be able to systematically identify, classify, and evaluate the most effective, applicable, and feasible CO2 improvement measures, it is essential to have an assessment framework, which has an environmental management perspective. Such a framework should be able to cover the widest range of potential CO2 improvement measures, therefore it has to have a wide system perspective and consider all material, and energy flows within the industry as useful resources. The first part of this thesis uses the concepts of Industrial Ecology and Industrial Symbiosis as the supporting theoretical concepts for developing such assessment framework. The framework has semi-qualitative approach for assessing different measures and is developed in two parts: (1) generic and (2) site-specific assessment. The first part considers general aspects of the measures such as level of Industrial Symbiosis (i.e. complexity of business approach), the potential of each measure for reducing CO2 emissions, and their technological maturity. The second part assesses the feasibility of the measures regarding the conditions of a specific cement producing system. Aspects such as organizational applicability, technical and infrastructural applicability, and the existing level of implementation of each measure are considered. In the second part of this thesis, the developed framework is applied on a selected cement production system which is a cluster composed of three cement plants in Germany (owned by CEMEX) referred to as the Cluster West. The result of the assessment provides insights about the state-of-the-art of CO2 improvement measures in cement industry in general and also demonstrates which of these measures are most (or least) suited for development in the Cluster West. The production system of the Cluster West has effectively applied CO2 improvement measures in areas such as producing blended cement products, using alternative fuels (and renewable fuels) for clinker production. In addition, its clinker production (the Kollenbach plant that is part of the Cluster West) has relatively good energy efficiency. According to the results of the assessment, CO2 improvement measures such as co-generation (producing electricity from excess heat of the plant), using renewable fuels, using alternative materials for clinker production, and increasing the usage of alternative fuels are among the most applicable choices for further implementation.
In relation with LIU-CEMEX Indsutrial Ecology project (2011)

APA, Harvard, Vancouver, ISO, and other styles

26

Elkadhi, Hayfa. "Trois essais sur les investissements dans les energies renouvelables." Thesis, Université Clermont Auvergne‎ (2017-2020), 2019. http://theses.bu.uca.fr/nondiff/2019CLFAD013_ELKADHI.pdf.

Full text

Abstract:

Au cours de ces dernières années, la croissance des investissements mondiaux dans les énergies renouvelables a été rapide. En effet, les énergies renouvelables (ER) sont considérées comme une alternative pour faire face au réchauffement climatique, à la raréfaction des ressources naturelles, à l’augmentation de la demande énergétique, à la volatilité des prix de l’énergie fossile et à la répartition inégale des sources énergétiques. Nous nous proposons dans cette thèse de mener une analyse visant à approfondir les réflexions sur l’investissement dans les ER (IER). Le premier objectif consiste à évaluer le retour sur l’IER. Nous avons choisi d’évaluer théoriquement et empiriquement l’impact de l’IER sur les émissions des Gaz à Effet de Serre (GES) et sur la Productivité Totale des Facteurs (PTF). Le deuxième objectif de cette thèse vise à évaluer l’impact des instruments de soutien au développement des ER (ISER) sur l’IER. Dans le premier chapitre, nous avons montré comment la relation entre les IER et les émissions de CO2 n’est pas linéaire, mais qu’elle prend la forme d’une courbe en U inversé. En d’autres termes, les IER ont un effet positif sur les émissions de CO2 jusqu'à ce que ces investissements atteignent un niveau donné, ou un certain seuil, au-delà duquel, les IER auront un impact négatif sur les émissions de CO2. Cette relation a été testé empiriquement en utilisant la régression en panel à transition brutale (PTR : Panel Threshold Regression model). Le deuxième chapitre de la thèse explore la relation entre l’investissement en énergie renouvelable (IER) et la productivité. En nous référant à la théorie de la croissance endogène, nous avons testé empiriquement notre hypothèse principale qui stipule que l’IER affecte positivement la croissance de la Productivité Totale des Facteurs. L’étude empirique a été réalisée sur un panel de 43 pays développés et en développement, à l’aide de la méthodologie de GMM-système. Au regard des résultats obtenus, cette étude a permis de confirmer notre hypothèse. En effet l’impact positif des IER sur la croissance de la PTF s’explique par le fait que l’IER encourage le transfert technologique et occasionne d'importantes retombées de connaissances (« knowledge spillover »). L’objectif du troisième chapitre consiste à discuter le rôle et l’impact des Instruments de Soutien au développement des ER (ISER) sur l’IER. Nous nous intéressons précisément à l’efficacité des ISER pour attirer les investissements en nouvelles capacité de production d’électricité à partir de sources d’énergie renouvelable. Nous pouvons déduire de notre étude que l’amélioration des IER passe généralement par les instruments de marché, et non pas par les instruments de commande et de contrôle, à l’exception des pays à faible revenu. D’ailleurs, une combinaison entre les instruments du « Market-pull » et du « Market-push » permet de soutenir les IER. Nous remarquons aussi que le soutien des IER passe par les instruments qui affectent indirectement ces investissements. En effet, pour encourager les IER, il vaut mieux agir en amont, en incitant la recherche, de développement et de déploiement (RDD) dans le secteur des ER, et en aval, en stimulant la production d’électricité renouvelable, à travers les tarifs d’achat garanti (les « Feed-in-Tariffs» )
Recently, growth in global investments in renewable energy (IRE) has been so rapid. In fact, renewable energy (RE) is considered as an alternative to deal with global warming, with the scarcity of natural resources, with the increase in energy demand, with the volatility of fossil fuel prices and with the unequal distribution of energy sources. This study attempts to shed more light on the IRE. The study’s prime goal is to evaluate the return on the IRE. It analyses theoretically and empirically the impact of the IRE on the greenhouse gas (GHG) emissions and on Total Factor Productivity (TFP). The study’s second goal is to evaluate the effectiveness of the policies that support the development of RE. The first chapter showed how the relationship between IREs and CO2 emissions is not linear, but, rather, it follows an inverted U-shaped curve. In other words, IREs have a positive impact on CO2 emissions until the investments reach a certain level, beyond which the IREs impact on CO2 emissions becomes negative. The current study has analyzed this relationship empirically by means of the panel threshold regression (PTR) model. The second chapter explores the relationship between IRE and productivity. Referring to the theory of endogenous growth, the study empirically tested the main hypothesis, that IRE positively affects the TFP growth. The empirical study was conducted on a panel of 43 developed and developing countries, using the GMM-system methodology. Study’s findings confirm that IRE have a positive affect on the Total Factor Productivity growth. Indeed, this positive impact is theoretically explained by the fact that the IRE encourages technology transfer and it generates significant knowledge spillovers. The third chapter of the thesis discusses the role and the impact of the policies that encourage the development of RE on IRE. Specifically, in this chapter we evaluate the effectiveness of these policies to attract renewable energy investments in electricity-generating capacity. The results show that the market instruments increase the IREs, although command or control instruments have no or a negative effect, with the exception of low-income countries. Moreover, a combination of "market-pull" and "market-push" instruments can supports the IREs. We also note that IRE support goes through the instruments that indirectly affect these investments. Indeed, to encourage IREs, it is better to act upstream, by spurring research, development and deployment (RDD) in the RE sector, and downstream, by stimulating the production of renewable electricity, through Guaranteed Purchase Rates or Feed-in-Tariffs (FIT)

APA, Harvard, Vancouver, ISO, and other styles

27

Li-Feng, Chen, and 陳吏鋒. "Effect of Methanol on the Performance and Emissions of SI Engine." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/73547989752569351430.

Full text

Abstract:

碩士
國立臺灣大學
機械工程學研究所
88
The octane value of methanol and 98-gasoline are 109 and 98, respectively. Methanol is an oxygenated compound, which ,mixed with gasoline, may improve the emissions of SI engine. The effect of methanol on the performance and emissions of SI Engine is investigated in this work. The control variables included the ratio of methanol in the fuel mixture (0%、5%、15%、25%), loads (10、20、30、40 N-m), engine speeds (1000、1500、2000、2500rpm),and fuel/air equivalence ratios (ψ).The purpose of his work is to find out how these variables affect the emissions of HC, CO, NOx, and the brake specific fuel consumption (bsfc). The results of this work are listed: (1) When the load and engine speed are increased, the exhaust temperature and NOX grow up. The concentration of CO remains unchanged, while the concentration of HC is slightly increased. (2) With the increase of the fraction of methanol, the exhaust temperature decreases. At the same time, the equivalence ratio of the highest exhaust temperature and the best engine’s thermal efficiency decrease. (3) With the increase of the fraction of methanol, NOX decreases. HC and CO decrease at X=5 and X=15 but increase at X=25. In addition, bsfc increases with the fraction of methanol. (4) If the air/fuel remains unchanged and the gasoline-methanol fuel are used, the exhaust emission will roughly be the same. But if the gasoline-methanol fuel is used on the best efficiency’s equivalence ratio, the exhaust emission will be improved.

APA, Harvard, Vancouver, ISO, and other styles

28

Henriques, João Gonçalo Cavaco. "Clustering of countries according to their contribution to GDP growth and its subsequent effect on co2 emissions." Master's thesis, 2019. http://hdl.handle.net/10071/21269.

Full text

Abstract:

A study on the EKC curve and the N-shaped relationship between CO2 emissions and GDP per capita with a focus on expenditure components of GDP contributions to GDP growth. The investigation took place for a balanced panel of 46 countries with data from 1971 to 2014. Explanatory variables for trade, investment and government expenditure are included in the form of the openness ratio, investment ratio and government size. Furthermore, clustering of the 46 countries according to the contributions of the components to the GDP growth using the k-means methods was conducted. The clusters were dummied and introduced as explanatory variables in the models. For more consistency, the Within-Between or Mundlak’s, a mixed model, estimator was used to estimate effects of the explanatory variables on CO2 emissions. A positive relationship between contributions of trade to GDP growth and subsequently trade and CO2 emissions was found. Furthermore, evidence for an N-shaped EKC curve was observed.
Um estudo focado na EKC e na relação polinomial de terceiro grau entre emissões de CO2 e PIB per capita com enfâse na contribuição dos componentes do PIB no crescimento do PIB. A investigação usa um painel balançado de 46 países entre os anos 1971 e 2014. Variáveis explanatórias para as trocas comerciais, investimento e despesa do governo foram introduzidas no modelo, usando o rácio de abertura, o rácio de investimento e o tamanho do governo. O método de agrupamento k-means foi usado para agrupar os 46 países de acordo com as contribuições dos componentes do PIB no crescimento do PIB. Estes agrupamentos foram introduzidos como dummies nos modelos. Para uma maior consistência o estimador de Mundlak, um estimador misto, foi utilizado. Uma relação positiva entre a contribuição das trocas comerciais e as emissões de CO2. Ainda mais, foi encontrada evidência de uma curva com a forma N.

APA, Harvard, Vancouver, ISO, and other styles

29

Huang, Shu-Lin, and 黃淑琳. "Effect of Elevated CO2 on Domesticated and Wild Plants and Insect Herbivores Performance." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/40868790430313168371.

Full text

Abstract:

碩士
國立中興大學
昆蟲學系所
104
Climate change refers to greenhouse effect, and carbon dioxide (CO2) is regarded as a main greenhouse gas that results in an increase of involving elevated global temperature. Previous studies have evaluated the effect of elevated CO2 on insect – plant interaction, but focused mainly on woody and cultivated crop plants. Little is known about the effects of elevated CO2 on wild plants. Crop domestication is a process of artificial selection, through that, the plant traits and allelochemistry of crop plants varied from wild relatives and thus may dramatically affect the plant-insect interactions. In present study, we examined the effect of elevated CO2 on Brassicaceae cultivated plant (Brassica oleracea var. botrytis L) and wild plant (Rorippa dubia Hara). In addition, to further understand CO2 effects on herbivores, we examined the direct and indirect impact of CO2 on specialist (Pieris rapae crucivora Boisduval) and generalist (Spodoptera litura Fabricius) herbivores performance. The results reveal that elevated CO2 enhanced plant performance and had influence on their nutrients and allelochemistry of wild plant, but not on cultivated plant. In addition, specialist herbivore was not affected by CO2 amount. These results suggest that elevated CO2 and crop domestication are apparently more effective to impact on generalist herbivores. Therefore, in the future elevated carbon dioxide environment, weedy plants might have more effects on the generalist herbivores.

APA, Harvard, Vancouver, ISO, and other styles

30

VROBEL, Radim. "Obchodování s povolenkami CO2." Master's thesis, 2012. http://www.nusl.cz/ntk/nusl-126501.

Full text

Abstract:

In this diploma thesis about the trading of permits CO2 to focus on the issue of release of carbon dioxide in a European context and its control through a system of tradable CO2 - EU ETS. I focus on the first two trading period of the EU ETS, in terms of allocated permits, price trends, and number of permits traded in the two periods in selected EU countries and the Czech Republic. The aim is to determine how appears a system of tradable CO2 permits in selected EU countries and the Czech Republic in the context of fulfillment obligations to reduce CO2 emissions under the Kyoto Protocol. The work compare the situation in the Czech Republic with selected EU countries in selected indicators of specific emissions trading and CO2. The work seeks to determine to what extent the ETS helps in improving the situation of individual countries in absolute production of CO2. The first chapter introduces the issue of climate change. It explains what are greenhouse gases, greenhouse effect and how this effect works. It acquaints readers with one greenhouse gas and that is carbon dioxide. Then the work explains how climate change takes place and there is also described climate history of the Earth, which is necessary to closer understanding of the issue. Then follows the description of international organizations, which deal with climate protection and have international influence. The second chapter focuses on ways to solution climate change. The bigger attention is devoted to the trading with carbon dioxide, than the work explaines the functioning of the European ETS, its development and global influence on the production and reduction of CO2. Than is the chapter devoted to notes and obligations that are promised in the Kyoto Protocol and closer specified the position of the Czech Republic in this Convention. In the third chapter compares the work selected countries of the European Union, which are the largest issuers of the Union's carbon dioxide. If it is possible to compare states in terms of their commitments and reduce CO2 implementation of these commitments. It appears that a large part of the EU Member States fulfill their obligations only partially, and some states it does not meet at all. For some selected countries we can see even an absolute increase in these emissions. Production of CO2 emissions is expressed in the comparison of selected countries in various indicators such as a production of CO2 per GDP or per inhabitant or per hectare of forest. It seems that not all states have aligned their emissions, which are important for sustainable development in that states. The last part compares selected countries in terms of allocated permits in the first and second ETS trading period and describes the evolution of both periods. Finally we performed a detailed analysis of price trends of permits especially in the first ETS period.

APA, Harvard, Vancouver, ISO, and other styles

31

Chen, Yung-Chuan, and 陳勇全. "The Effect of Assisting Gasoline Injection & Fuel Additiveon the Diesel Engine Performance & Exhaust Emissions." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/07717095458401629619.

Full text

Abstract:

碩士
國立雲林科技大學
機械工程系碩士班
93
This research is performed on a YAMAHA ME200F three cylinder direct injection diesel engine. The total fuel heating value injected into the engine under the assistant gasoline injection into the intake manifold is maintained the same as the baseline case. This is the same for the cases which the diesel fuel is mixed with fuel additives. Under such energy balance situation, the engine out emissions, the cylinder pressure, and the heat release rate are studied to understand the effects of either duel fuel injection or fuel additive application on the engine performance. The six fuel additives investigated in this research include MTBE, DMC, Monoglyme, Diglyme, EHN, and DTBP. The assistant duel fuel injection has the CPC 92 unleaded fuel. The most effective duel on the improvement of engine performance is then concluded in this study. Three part of the experimental works are category as follws: The first part investigates the duel fuel (gasoline injection) premixed lean mixture effects on the engine performance. The results show the NOx is substantially reduced (up to 70% at some testing point). The HC and CO emissions are somehow increased. The engine output is suffered in this study; however, the effective BSFC (E-BSFC) is increased. The second part has the six fuel additives tested. Results show that the NOx emission can be reduced by 30% and HC emission by 18%. Howeve, the CO emission is up by 42%. The engine output is slightly increased by 2~6 % and the E-BSFC is reduced by 6%. These kinds of results are considered as favorite in engine operation. The third part combined both the first and second parts shown before. Results show that the NOx emission can be reduced by 48% even though the HC and CO emissions are increased.(especially for the CO emission). The engine output is slightlu reduced and the E-BSFC is slightly increased. This study has shown the positive effects on the NOx emission through the usage of duel fuel injection. The fuel additives in general have good results on the exhaust emissions and engine output )or E-BSFC).

APA, Harvard, Vancouver, ISO, and other styles

32

Teawkul, Papitchaya, and 張麗婷. "Elevated of CO2 and AM fungi effect on tomato plant and subsequently on Spodoptera litura performance." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/48870538226986475962.

Full text

Abstract:

碩士
國立中興大學
昆蟲學系所
103
The elevated carbon dioxide (CO2) in the atmosphere due to climate change has been found to impact the relative amount of carbon and nutrients in the plants. The changes in plant chemistry are major factors resolving the value of a plant as a food source to herbivorous insects. However, past studies most focused on effects of CO2 on temperate forest trees; little is known about effects of elevated CO2 on crop plants in the subtropical areas. The purpose of this study assessed the effect of elevated CO2 and soil microbial on chemistry, performance of plant and their insect pest. This thesis can be divided into two chapters; in chapter one, the effects of CO2 on tomato plant (Lycopersicon esculentum Mill.) performance, chemistry, and subsequently on Spodoptera litura performance had been investigated. The results indicated that the elevated CO2 had positive effect on tomato plant’s performance. However, elevated CO2 negatively affected plant nutrition. In addition, the raised CO2 concentration had negative impact on the growth performance of S. litura larvae. Besides the effects of elevated CO2, the effect of beneficial microorganism is known for the promotion of plant growth and the improvement of the plant nutrition status. Only handful studies have focused on the interaction of elevated CO2 and arbuscular mycorrhizae (AM) fungi to plants and insects. The objective of the second chapter of this study assessed the effect of elevated CO2 and AM fungi on tomato plant growth, foliar chemistry, and on subsequently S. litura performance. This research revealed that both the elevated CO2 and AM fungi can strongly influence the physiology and foliar chemistry of tomato plants. Moreover, the changes of phytochemistry in the plants may play an important role in affecting the growth performance of insect.

APA, Harvard, Vancouver, ISO, and other styles

33

Freitas, Cátia José Abreu. "Effect of elevated CO2 concentrations and irradiance on the photosynthetic performance of the seagrass Cymodocea nodosa." Master's thesis, 2015. http://hdl.handle.net/10400.1/8138.

Full text

Abstract:

Dissertação de Mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015
Durante 800000 anos a concentração de dióxido de carbono (CO2) na atmosfera permaneceu entre 172-300 partes por milhão (ppm). No entanto, após a era industrial, a concentração de CO2 atmosférico sofreu um aumento sem precedentes para os níveis atuais de aproximadamente 391 ppm de CO2, consequência da atividade antropogénica, como a queima de combustíveis fósseis. Atualmente, cerca de 30 % da totalidade de CO2 emitido para a atmosfera é absorvido pelo oceano, levando à diminuição do pH e alterando a química dos carbonatos na água, processo que resulta na acidificação do oceano. Apesar dos previstos impactos potencialmente negativos da acidificação do oceano nos ecossistemas e organismos marinhos, as diferentes espécies não serão identicamente afetadas. As pradarias de ervas marinhas, angiospérmicas que se adaptaram a uma existência totalmente submersa, constituem um dos habitats marinhos e costeiros mais produtivos do planeta. São responsáveis pelo melhoramento da qualidade da água e promovem o aumento da biodiversidade disponibilizando habitat para outras espécies. No entanto, até à data, o efeito da acidificação do oceano na biologia e ecologia destas plantas marinhas é pouco conhecido, ainda que esteja prevista a estimulação positiva das taxas fotossintéticas e de crescimento com o aumento do CO2. Compreender como as pradarias de ervas marinhas serão afetadas pelo enriquecimento de CO2 na água será decisivo para a criação de futuras medidas de conservação e gestão de ecossistemas costeiros. O principal objetivo deste estudo foi o de investigar o efeito de elevadas concentrações de CO2 na ecofisiologia da fotossíntese de Cymodocea nodosa sob diferentes intensidades e qualidades de luz em condições ambientais controladas. Amostras de C. nodosa foram recolhidas na Baía de Cádiz, em Espanha e transportadas para a Estação de Experimental do Ramalhete (CCMar), Faro, Portugal, onde se desenvolveu toda a experiência. Rizomas terminais de C. nodosa foram aleatoriamente distribuídos em diferentes tanques contendo substrato arenoso. A experiência compreendeu um período de aclimatação que precedeu o período experimental, este último com duração de duas semanas. Os parâmetros físico-químicos e os parâmetros fotossintéticos derivados da fluorescência da clorofila a foram monitorizados diariamente. Diferentes processos fisiológicos foram estudados de forma a elucidar como a estrutura e o funcionamento dos sistemas de captura de energia luminosa variam em ambientes luminosos diferenciados. Foram realizadas curvas de resposta da fotossíntese à luz com base na libertação/consumo de oxigénio e com base na taxa de transporte de eletrões através de um elétrodo de oxigénio tipo Clark e de um fluorómetro Diving-PAM, respetivamente. As clorofilas foram quantificadas espectrofotometricamente e os carotenoides foram quantificados por cromatografia líquida de alta eficiência (HPLC). Mediu-se também a eficiência fotoquímica máxima do fotossistema II (Fv/Fm). Em tratamentos com baixa intensidade luminosa o aumento da pressão parcial de CO2 resultou em maiores taxas fotossintéticas máximas (Pmáx), no entanto este aumento em Pmáx não se fez acompanhar pelo aumento da eficiência fotossintética (α). Perante níveis atuais de CO2 atmosférico e entre tratamentos com baixa intensidade luminosa o valor de Pmáx foi superior quando a qualidade espectral foi limitada ao comprimento de onda da luz azul. Os níveis elevados de CO2 na água aumentaram também as taxas de respiração no escuro quando comparado com as mesmas taxas a níveis de CO2 de referência, no entanto este aumento foi apenas significativo para plantas em tanques sem qualquer atenuação luminosa. A máxima taxa relativa de transporte de eletrões (rETRmáx) e a irradiância de saturação (Ik) foram significativamente reduzidas em condições de baixa intensidade luminosa, independentemente da concentração de CO2. Em tratamentos sem atenuação luminosa a rETRmáx foi alcançada apenas quando a intensidade da luz foi aproximadamente 150 μmolesfotões.m-2.s-1, ao contrário dos tratamentos onde a intensidade luminosa foi atenuada, em que a rETRmáx foi alcançada a baixas irradiâncias (a partir de 74.4 μmolesfotões.m-2.s-1) resultando num coeficiente da utilização da luz (α) significativamente superior. A eficiência fotoquímica máxima do fotossistema II foi significativamente superior em plantas aclimatadas a baixas intensidades luminosas. A intensidades luminosas naturais, o rácio Fv/Fm foi superior em plantas com elevada disponibilidade de CO2 na água. Relativamente ao pigmentos fotossintéticos, as concentrações de clorofila a (Chl a), b (Chl b) e clorofila total (Chl T) foram significativamente superiores em Cádiz do que após o período experimental, no entanto não se registaram alterações significativas no rácio de clorofila a/b (Chl a/b). Nos tratamentos sem atenuação da luz, a taxa de desepoxidação dos pigmentos do ciclo das xantofilas, violaxantina (V), anteraxantina (A) e zeaxantina (Z) - (AZ/VAZ) - foi significativamente superior do que nos tratamentos com baixas intensidades luminosas. O rácio entre os pigmentos do ciclo das xantofilas e a clorofila total [(VAZ)/ChlT] foi menor em plantas aclimatadas a baixa disponibilidade luminosa, independentemente do tratamento de CO2. De uma forma geral, os resultados obtidos sugerem que distintas condições luminosas induziram diferenças mais acentuadas na ecofisiologia da fotossíntese de C. nodosa do que o aumento da pCO2. RuBisCO é a enzima que catalisa a fixação primária do CO2 na fotossíntese, no ciclo de Calvin, em plantas C3. A maioria das espécies de ervas marinhas são classificadas como plantas C3, no entanto, há estudos que apontam para a ocorrência do metabolismo fotossintético C4 (ex. Cymodocea serrulata). No estado atual do conhecimento, em plantas C4 o aumento do CO2 não resulta em alterações na resposta fotossintética, uma vez que a fixação primária de carbono é catalisada pela enzima fosfoenolpiruvato carboxilase (PEPC’ase), que ao contrário da RuBisCO não é afetada pela concentração de O2, minimizando a fotorrespiração e tornado a fotossíntese saturada para a atual concentração de carbono inorgânico (Ci). No entanto, e contrariamente ao que é ocasionalmente assumido, C. nodosa não apresentou respostas que indiquem um estado de saturação relativamente à atual concentração de carbono inorgânico uma vez que neste estudo o aumento do CO2 resultou em maiores taxas fotossintéticas máximas em ambientes com baixa intensidade luminosa. Os resultados obtidos indicam ainda que em condições luminosas limitantes, a qualidade da luz poderá ter um papel-chave na resposta fotossintética da planta. A redução nas taxas relativas de transporte de eletrões, a diminuição da irradiância de saturação e o aumento do coeficiente de utilização de luz são típicos indicadores de plantas adaptadas a baixas intensidades luminosas. Adaptações fisiológicas de plantas de C. nodosa em diferentes locais e ambientes marinhos podem resultar em alterações na concentração dos pigmentos fotossintéticos, sem implicar uma perda de performance fotossintética ou uma alteração no seu estado fisiológico. Os rácios entre pigmentos fotossintéticos revelam o investimento na pool dos pigmentos do ciclo das xantofilas e a ativação do seu ciclo de desepoxidação/epoxidação como respostas a elevadas intensidades luminosas. As respostas de diferentes espécies de ervas marinhas à mudança nos padrões ambientais devem ser interpretadas cautelosamente uma vez que podem ser altamente específicas para cada espécie.

APA, Harvard, Vancouver, ISO, and other styles

34

Pierpont, David A. "An experimental study of the effect of injection parameters and EGR on D.I. Diesel emissions and performance." 1994. http://catalog.hathitrust.org/api/volumes/oclc/32830312.html.

Full text

Abstract:

Thesis (M.S.)--University of Wisconsin--Madison, 1994.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 98-100).

APA, Harvard, Vancouver, ISO, and other styles

35

Chiu, Chun-Hsiang, and 邱俊翔. "Effect of Hydrogen-Rich Gas on the Performance and Exhaust Emissions of 4-Stroke Cycle Carburetor Motorcycle." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/mxv565.

Full text

Abstract:

碩士
崑山科技大學
機械工程研究所
96
In this research, the hydrogen and nitrogen were mixed to hydrogen-rich gas. The 4-stroke carburetor motorcycle engine was used to evaluate the effect of hydrogen-rich gas on the performance and exhaust emissions. The effect of intake-gas positions, different hydrogen-rich gas volume ratio(100-30%), hydrogen-rich gas flow rate(14-35L/min) and speed (40、60、80km/hr) were investigated The results of this research showed that: Hydrogen-rich gas could make engine with higher performance. When speed at 80km/hr, hydrogen-rich gas volume ratio70% and flow rate 28L/min, it increased 26% of brake power. If raised hydrogen content, the mix-gas concentration would be over and power reduced. The hydrogen-rich gas had better performance than pure hydrogen gas. When hydrogen-rich rate gas reduced, the CO and HC engine exhaust emissions were decreased. When hydrogen-rich gas is at low ratio and low flow ratio, it has the 7% CO emissions improved. The increasing of hydrogen content on mix-gas will make engine with rich-gasoline combustion, then the engine combustion temperature will low and with incompletion combustion. So NOX and CO2 exhaust emissions concentration will get lower. When motorcycle with high ratio and high flow rate hydrogen-rich gas at 40km/hr, 80km/hr, NOX have the improvement of 92% exhaust emissions.

APA, Harvard, Vancouver, ISO, and other styles

36

GAO, YI-XIANG, and 高翊翔. "Effect of engine ignition angle on the performance and exhaust emissions of low concentration bio-butanol mixtures." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/mx865f.

Full text

Abstract:

碩士
明志科技大學
機械工程系機械與機電工程碩士班
106
In recent years, the energy crisis and environmental pollution issues have received international attention. All countries in the world are also actively pursuing the research and development of alternative energy sources and reducing emissions of environmental pollutants.The density of scooter in Taiwan is the highest in the world. Therefore, scooter often emit more pollutants than other private vehicles. Therefore, this study uses the general market through the fifth phase of environmental inspection scooter. And bio-butanol (butyl propionate) and gasoline mixed fuel dual fuel hybrid combustion, observe the impact of exhaust emissions and performance, and then observe the changes of exhaust emissions and performance through ignition positive adjustment.The bio-butanol used in the study was used by different previous authors. The bio-n-butanol used in this study is bio-butanol, named butyl propionate (BP) provided by Prof. Su Jiahong. According to the report of Prof. Su Jiahong, esterification reaction of butanol and propionic acid catalyzed by various lipases is carried out in a solvent-free system.Butyl propionate (BP) is a product of lignocellulose. Fermentation of cellulose, hemicellulose and lignin to bio-butanol using microorganisms. It is a colorless and fruity liquid that acts as a soluble nitrocellulose and solvent for natural and synthetic resins. And the response surface methodology (RSM) was used to optimize the process of esterification, and under the optimal reaction conditions, the efficiency of reusing biocatalyst was increased and the yield of butyl propionate (BP) Can effectively quantify the production of the future can be widely used to replace the limited fossil fuel. The effects of butyl propionate and gasoline blends on the performance of single-cylinder spark ignition engines and the effects of exhaust emissions. The effects of butyl propionate and gasoline blends on the performance of single-cylinder spark ignition engines and the effects of exhaust emissions. The experimental results show that when the content of butyl propionate is higher, the performance and CO2 and NOx tend to increase, and CO and HC tend to decrease. The influence of the ignition angle on the performance of the mixed fuel of butyl acrylate and gasoline in the performance of a single cylinder spark ignition engine and exhaust emissions.Based on the original set ignition advance angle Crank angle before top dead center 28° (CA BTDC 28°), The experimental results show that when the ignition angle advances, the performance and CO2 and NOx will increase, while HC and CO will decrease. Conversely, when the ignition angle is delayed, the performance and CO2 and NOx will decrease. HC and CO will have a rising trend. In the study of the effects of butyl propionate and gasoline blended fuel on the temperature of a single cylinder spark ignition engine. The experimental results show that when the content of butyl propionate is higher, the engine temperature, spark plug temperature, and the temperature of the exhaust pipe will increase. The influence of the ignition angle on the temperature of the mixed fuel of butyl propionate and gasoline in the single cylinder spark ignition engine. Based on the original setting of the ignition advance angle Crank angle before top dead center 28° (CA BTDC 28°), The experimental results show that when the ignition angle is advanced, the engine temperature, spark plug temperature, and the temperature of the exhaust pipe will increase. Conversely, when the ignition angle is delayed, the engine temperature, spark plug temperature, and the exhaust pipe front There will be a downward trend in temperature.

APA, Harvard, Vancouver, ISO, and other styles

37

Jian-YiHe and 何建頤. "Effect of Rich Oxygen and Hydrogen Rich Gas on Operating Performance and Exhaust Emissions for Closed Cycle Diesel Engine." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/92527377728429238196.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Luo, Mei-Tao, and 羅美滔. "A Study of the effect of iso-propanol additive on the performance and exhaust emissions for a diesel engine." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/25833479196751136121.

Full text

Abstract:

碩士
國立臺灣海洋大學
機械與輪機工程學系
93
Abstract Alcohols are oxygen-enriched fuels. Thus alcoholic fuel additives are able to promote the combustion of diesel engines, and to reduce the exhaust emissions of CO and smoke. Depending on the type of alcoholic fuel additives used, the exhaust NOX emissions may increase or decrease. Isopropyl alcohol (IPA) has a similar value of specific weight as diesel fuel. It has a high potential to serve as an alternate fuel for diesel engines. This study is to investigate the effects on the performance and exhaust emissions by adding different proportions of IPA into diesel fuel for a diesel engine under different loads and speeds. The experimental results shows that the bsfc of diesel engine can be effectively reduced by adding little amount of IPA into diesel fuel. But if too much IPA is added, the bsfc would be even larger then the engine burning pure diesel fuel. Adding IPA has minor improvement on the bsCO when the engine is under light or middle loads. It is noticeable that when the engine is under heavy loads, by adding IPA, the bsCO may be reduced to one half of the bsCO expelled from the engine burning pure diesel fuel. When IPA is added into diesel fuel, the experimental results also show that the bsNOXof diesel engine is also observably reduced.

APA, Harvard, Vancouver, ISO, and other styles

39

Cheng, Chin-Han, and 鄭錦翰. "The Study on Performance, Fuel Consumption, and Exhaust Emissions Effect of Methanol-Super Diesel Mixture Fuel in Direct Injection Diesel Engine." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/s9f349.

Full text

Abstract:

碩士
國立臺北科技大學
車輛工程系所
100
Diesel engines have the advantage of high thermal efficiency, maximum torque output, cheap oil, stability and durability. So diesel engine has an important contribution in dynamic machine, such as vehicle, ship, agri-motor etc. It is effective contributions to develop world economy. But the contaminant of diesel engines, such as smoke, NOX and HC emissions will lead air pollution to damage respiratory disease. In order to reducing exhaust emission, the theme of theses analyze that super diesel fuels are added by 90% with high-purity methanol additive and 5% water-contented methanol additive in non-modified diesel engines, respectively. The results show that the anhydrous methanol mixed fuel has higher BSFC value, the smoke, NOX, HC emissions and exhaust gas temperature, however, is lower than super diesel; the methanol mixed fuel with water which contains lower heating value also has higher BSFC value, but the smoke, NOX and HC emission levels, as well as exhaust gas temperature are lower than the anhydrous methanol mixed fuel.

APA, Harvard, Vancouver, ISO, and other styles

40

Huang, Wei-Tsang, and 黃威蒼. "The Study on Performance, Fuel Consumption, and Exhaust Emissions Effect of Butanol Fuel Mixture Super Diesel Fuel in Direct Injection Diesel Engine." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/gr296n.

Full text

Abstract:

碩士
國立臺北科技大學
車輛工程系所
100
With industrial developing, fossil energies are widely used; they produce some problems like a large number of exhaust pollutants and the greenhouse effect. In this study, we use the characteristics of the high oxygen content and low carbon content of the alcohol fuel to reduce the concentration of pollutants in the exhaust emissions from diesel engines. In the procedure, the super diesel fuel is added by 90 wt% with high-purity butanol additive and 5 wt% water-contented butanol additive in non-modified diesel engine, respectively. The results show that the butanol mixed fuel has higher BSFC value, higher HC emissions and lower BMEP value than super diesel fuel, however, the Smoke, NOx, exhaust gas temperature are lower than super diesel; the butanol mixed fuel with water-contented additive also has higher BSFC value and BMEP value, yet the Smoke, Nox, HC emission levels, and exhaust gas temperature are lower than the butanol mixed fuel without water.

APA, Harvard, Vancouver, ISO, and other styles

41

Lee, Kuo-Yu, and 李國裕. "The Study on the Effect of Engine Performance and Exhaust Emissions on DI Diesel engine by using Nanometer Ceramic Complexes Powder Lubricant Additives." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/ec7693.

Full text

Abstract:

碩士
國立臺北科技大學
車輛工程系所
100
Nano Powder Technology is explored on many territories. It plays a very important role in the future technological development. Since Nano Powder Technology has flourished in the past few years, many traditional territories in science technology and reducing wear technology can change the material of the mechanical, manufacturing processes and production methods. Many references also prove that it can reduce friction performances in Tribological territory. In this study, Nanometer Ceramic Complexes Powder Additive, also called NCCPA, is added into the original lubricating oil, and we test NCCPA’s ability in a single cylinder direct injection diesel engine experiments and compare with the original lubricating oil. The results show that NCCPA trial in diesel engine could diminish fuel consumption 1.30%, smoke concentration 18.87%, NOX concentration 2.99%, HC concentration 9.41% and can dwindle exhaust temperature 1.24% as well. It can prove that adding NCCPA into the original lubricating oil can diminish fuel consumption and emissions, and it augments the engine performance and the sealing of cylinder to ameliorate lubrication performance. NCCPA undoubtedly thus accomplishes the goal of energy saving.

APA, Harvard, Vancouver, ISO, and other styles

42

Lozano, Adolfo. "Analysis of a novel thermoelectric generator in the built environment." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-08-4131.

Full text

Abstract:

This study centered on a novel thermoelectric generator (TEG) integrated into the built environment. Designed by Watts Thermoelectric LLC, the TEG is essentially a novel assembly of thermoelectric modules whose required temperature differential is supplied by hot and cold streams of water flowing through the TEG. Per its recommended operating conditions, the TEG nominally generates 83 Watts of electrical power. In its default configuration in the built environment, solar-thermal energy serves as the TEG’s hot stream source and geothermal energy serves as its cold stream source. Two systems-level, thermodynamic analyses were performed, which were based on the TEG’s upcoming characterization testing, scheduled to occur later in 2011 in Detroit, Michigan. The first analysis considered the TEG coupled with a solar collector system. A numerical model of the coupled system was constructed in order to estimate the system’s annual energetic performance. It was determined numerically that over the course of a sample year, the solar collector system could deliver 39.73 megawatt-hours (MWh) of thermal energy to the TEG. The TEG converted that thermal energy into a net of 266.5 kilowatt-hours of electricity in that year. The second analysis focused on the TEG itself during operation with the purpose of providing a preliminary thermodynamic characterization of the TEG. Using experimental data, this analysis found the TEG’s operating efficiency to be 1.72%. Next, the annual emissions that would be avoided by implementing the zero-emission TEG were considered. The emission factor of Michigan’s electric grid, RFCM, was calculated to be 0.830 tons of carbon dioxide-equivalent (CO2e) per MWh, and with the TEG’s annual energy output, it was concluded that 0.221 tons CO2e would be avoided each year with the TEG. It is important to note that the TEG can be linearly scaled up by including additional modules. Thus, these benefits can be multiplied through the incorporation of more TEG units. Finally, the levelized cost of electricity (LCOE) of the TEG integrated into the built environment with the solar-thermal hot source and passive ground-based cold source was considered. The LCOE of the system was estimated to be approximately $8,404/MWh, which is substantially greater than current generation technologies. Note that this calculation was based on one particular configuration with a particular and narrow set of assumptions, and is not intended to be a general conclusion about TEG systems overall. It was concluded that while solar-thermal energy systems can sustain the TEG, they are capital-intensive and therefore not economically suitable for the TEG given the assumptions of this analysis. In the end, because of the large costs associated with the solar-thermal system, waste heat recovery is proposed as a potentially more cost-effective provider of the TEG’s hot stream source.
text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'CO2 emissions effect on E performance'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles