| 1. |
- De Castro Marins, Karin Regina
(author)
-
Balanced assessment of energy systems : Integrating energy usage & supply
- 2006
-
In: PLEA - Int. Conf. Passive Low Energy Archit., Conf. Proc.. ; , s. II189-II194
-
Conference paper (peer-reviewed)abstract
- The present topic approaches energy systems, building and urban design in an integrated path. The objective of the project was to develop a methodology for balanced assessment of energy systems, considering two main pillars: Energy Usage and Energy Supply. Load management, cost, and environmental impact are analysed in order to identify a better overall performance, by the combination of initiatives in both sides. The research includes, in the energy usage side, design and management strategies for energy efficiency in residential and commercial buildings, and in urban planning as well. In the energy supply side, it includes decentralised systems in building scale, and centralised systems in neighbourhood and city scale. Electricity, space heating, and space cooling are considered. A quantitative assessment module and graphical interfaces were developed to support project development and decision-making, and demonstrate advantages of integrated approaches. A study-case was performed, corresponding to a master plan for urban development of the city of Miyun, in China, supposed to be a model of sustainable development. The project strongly emphasizes the need for relationship of dependent variables included in the design and management of city, building and energy systems, aiming to contribute to a more mature approach towards sustainability.
|
|
| 2. |
- Stenlund Nilsson Ivner, Jenny, 1976-
(author)
-
Plan and Reality : Municipal Energy Plans and Development of Local Energy Systems
- 2006
-
Licentiate thesis (other academic/artistic)abstract
- Enligt lagen om kommunal energiplanering ska varje svensk kommun ha en energiplan för tillförsel för tillförsel och användning av energi. Huruvida energiplanering är ett bra sätt att styra det kommunala energisystemet är dock omdebatterat. Denna avhandling studerar innehåll i, och implementering av, ett antal svenska kommunala energiplaner. Energiplanernas effektivitet studeras på två nivåer: uppfyllelse av mål och visioner i planerna, samt hur detta bidrar till att uppfylla de nationella energipolitiska målen.Forskningen baseras på tre studier: en studie av innehållet i tolv energiplaner från Östergötland, en studie av mål och visioner i sju energiplaner och hur energisystem utvecklats efter energiplanerna antagits, samt en fallstudie av Kungälvs kommun där mål och måluppfyllelse studerats mer utförligt. Innehåll och målformuleringar i energiplanerna har analyserats med avseende på miljö, effektiv energianvändning och systemnivå. Mål och måluppfyllelse har även analyserats med avseende på aktörer.Resultaten visar på att de studerade energiplanerna har smal systemsyn och att de miljöanalyser som finns i planerna är undermåliga. Energiplaneringen har varit effektiv till viss del. Bäst måluppfyllelse har kommunerna när det gäller mål på en relativt låg systemnivå och när det är kommunen själv som äger frågan, exempelvis fjärrvärmeutbyggnad och energieffektivisering av kommunens lokaler. När det gäller utvecklingens bidrag till de nationella energipolitiska målen är resultaten varierande: användning av biobränslen har ökat avsevärt, medan självförsörjningsgraden på el bara ökat något. Bäst är utvecklingen när det gäller minskade koldioxidutsläpp.Baserat på bristerna som upptäckts i de studerade energiplanerna och dess implementering förs en diskussion kring möjligheter att öka energiplaneringens effektivitet och vidga systemsynen. Förbättringar som diskuteras är att stärka kopplingen till fysisk planering, och att inkludera medborgarmedverkan och miljöbedömningar. Om kopplingen till energifrågor stärks i översiktlig planering och om även privata aktörer kommer till tals under planeringsprocessen, skulle detta kunna underlätta implementering av energiplanerna. Miljöbedömningar i sin tur kan bidra med en vidare systemsyn om mer relevanta mål i planerna. Slutligen föreslås att ramverket för miljöbedömning av planer och program (2001/42/EC) kan användas vid energiplanering eftersom det framhåller vikten av breda analyser, samråd med privata aktörer och miljöbedömningar.
|
|
| 3. |
- Åstrand, Kerstin
(author)
-
Energy Policy Instruments Perspectives on their Choice, Combination and Evaluation
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- Abstract The thesis aims at providing a better understanding of public policy instruments used in policy-making within the energy sector, particularly regarding their role in the change towards an increased use of renewable energy sources for generation of electricity. The research was guided by an underlying assumption that a markedly higher proportion of the energy generated from renewable sources can be considerably enhanced by use of policy instruments that support the development and the market creation of new, renewable energy technologies. The thesis consists of two parts. In the first part, the effects that policy instruments can have on technological development and the creation of markets are examined. The issue was empirically examined in connection with the wind power development in Sweden. The underlying aim was to identify potential measures that could be useful in terms of increasing the effectiveness of governmental interventions directed at effecting change in energy systems. Two such measures of relevance to energy policy-making could be identified. First, it was concluded that obtaining a balanced combination of policy instruments supporting technological development and the creation of markets for new technologies is of importance; i.e. reducing the risk of a premature lock-in of technologies that could turn out to be inferior in the long run. Secondly, it was concluded that evaluating the outcome of policy programmes in the sense of their effect on technological change, can be important in increasing the effectiveness of policy interventions. It was suggested that a systematic, continuous and systems-based approach to evaluation can be useful for the feedback on ongoing programmes and for the input on future decisions concerning relevant interventions. The second part of the thesis is concerned with policy formation; i.e. the process of choosing and adopting policy instruments. How policy instruments are selected and the factors that influenced this are analysed in the case of the Swedish green certificate trading scheme. The choice was shown to be based on a combination of factors. These included the characteristics of the instrument, in terms of cost-efficiency, non-interference with a deregulated electricity market and the effectiveness in terms of achieving a quantitative target. The choice was also found to be influenced by both the domestic and the European context and by the policy makers? preferences for market-based alternatives. EU policies appear to have strengthened the preferences for a market-based support scheme, as well as providing additional justification of the preferences for a specific instrument. The findings obtained highlight the complexity of public policy-making, helping to provide a better understanding of the broader context of changing energy systems. On the whole, the findings can be seen as contributing to knowledge of the societal aspects of technological solutions involved in the transition to a more sustainable energy system. The findings can also provide input to future research and can help policy makers to select more promising policy options and to improve the planning, design and evaluation of policy instruments or to refine ongoing policy programs.
|
|
| 4. |
- Di Benedetto, M. D., et al.
(author)
-
Wireless ventilation control for large-scale systems : The mining industrial case
- 2009
-
In: 2009 6th IEEE Annual Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks Workshops. - 9781424439386
-
Conference paper (peer-reviewed)abstract
- Mining ventilation is an interesting example of a large scale system with high environmental impact where advanced control strategies can bring major improvements. Indeed, one of the first objectives of modern mining industry is to fulfill environmental specifications [1] during the ore extraction and crushing, by optimizing the energy consumption or the production of polluting agents. The mine electric consumption was 4 % of total industrial electric demand in the US in 1994 (6 % in 2007 in South Africa) and 90 % of it was related to motor system energy [2]. Another interesting figure is given in [3] where it is estimated that the savings associated with global control strategies for fluid systems (pumps, fans and compressors) represent approximately 20 % of the total manufacturing motor system energy savings. This motivates the development of new control strategies for large scale aerodynamic processes based on appropriate automation and a global consideration of the system. More specifically, the challenge in this work is focused on the mining ventilation since as much as 50 % or more of the energy consumed by the mining process may go into the ventilation (including heating the air). It is clear that investigating automatic control solutions and minimizing the amount of pumped air to save energy consumption (proportional to the cube of airflow quantity [4]) is of great environmental and industrial interest.
|
|
| 5. |
- Zanki Alujevic, Vlasta
(author)
-
Energy use and environmental impact from hotels on Adriatic Coast in Croatia : current status and future possibilities for HVAC systems
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- This thesis analyses a specific type of energy usage system, “energy usage in hotels”, and how this system behaves. In order to evaluate the current state of energy use in hotels, an energy audit questionnaire was developed and conducted among 31,5% of hotels on the Adriatic coast. The energy audit was used as a tool to set a benchmark for energy consumption in hotels and to identify opportunities for increased energy efficiency measures in HVAC systems. The analysis has shown that the average energy consumption in hotels on the Adriatic coast is in the range of 159 to 180 kWh/m2 and 162 to 225 kWh/m2 for seasonal and non seasonal hotels respectively. In order to establish a relationship between different independent variables in the hotels (total floor area and number of rooms) and dependent variables, such as electricity and oil consumption, mathematical statistical methods, such as correlation and regression analysis, were implemented. The objective of this thesis was also to develop - from an energy, environmental and economical points of view - a methodology for the design and retrofit of HVAC systems in the hotels on the Adriatic coast. The methodology named HOTECO is based on a system thinking approach. With respect to the technological aspects, the first step was to analyse conventional HVAC system designs and to compare it with the three most promising alternative HVAC systems utilizing renewable energy sources for a typical hotel. Computer modelling in TRNSYS was used to assess energy consumption. TRNSYS software has been used for simulations for a number of years, is internationally recognized, and has been validated and verified. It was concluded that energy and environmental savings in hotels on the Adriatic coast could be achieved using readily available technologies. The HOTECO methodology also demonstrated a framework that supports decision making iv regarding system selection and operational strategies to limit environmental impact from HVAC systems in hotels. Four scenarios for energy consumption in hotels on the Adriatic coast with regards to current state of energy systems and improved retrofit solutions utilizing renewable energy source were given.
|
|
| 6. |
- Nair, Gireesh, 1973-, et al.
(author)
-
Adoption of energy efficiency measures in swedish detatched houses
- 2009
-
In: International Scientific Conference on Energy systems with IT, March 11-12, in connection with 'Energitiget 2009', Stockholm, Sweden.
-
Conference paper (peer-reviewed)abstract
- The paper focuses on Swedish homeowners’ need for and perceptions about adopting building envelop energy efficiency measures such as improved windows and attic and wall insulation. The results of a questionnaire surveying 3000 randomly selected homeowners during the summer of 2008 revealed that about 70-90% of the respondents had no intention of implementing such a measure over the next 10 years. The main reasons for non-adoption were that homeowners were satisfied with the physical condition, thermal performance, and aesthetics of their existing installations. A greater proportion of respondents perceived that improving attic insulation has more advantages than other measures, but windows were more likely to be installed than attic insulation was to be improved. Respondents gave high priority to economic factors in deciding on an energy efficiency measure, while environmental aspects were given lower priority. Hence, economic incentives could be useful in promoting the adoption of building envelope energy efficiency measures. Interpersonal sources, construction companies/installers, and energy advisers were important sources of information for homeowners as they planned to install energy efficiency measures.
|
|
| 7. |
- Surroop, Dinesh, et al.
(author)
-
Waste to energy : A source of energy to reduce greenhouse gas in mauritius
- 2008
-
In: Air and Waste Management Association. - 9781605603797 - 9781605603797 ; , s. 755-765
-
Conference paper (peer-reviewed)abstract
- Energy is one of the most basic of human needs and is extremely crucial for continued human development. The global demand for energy is rapidly increasing with increasing human population, urbanization and modernization. The growth in global energy demand is projected to rise sharply over the coming years. The enormous amount of energy being consumed across the world is having adverse implications on the ecosystem of the planet. The world heavily relies on fossil fuels to meet its energy requirements. Fossil fuels are inflicting enormous impacts on the environment. Climatic changes driven by human activities, in particular the production of greenhouse gas emissions (GHG), directly impact on the environment. Municipal Solid Waste (MSW) is regarded as biomass; therefore almost all the carbon dioxide generation from the combustion system should be carbon neutral. Since there are around 1200 tons of MSW generated daily in Mauritius, this can be a good source of energy. The study was, therefore, initiated to assess the amount of GHG being avoided by using MSW as a source of energy. The results showed that that the amount of energy per unit weight that is generated from MSW was 1.85 kWh/kg. The amount of GHG emitted from combustion of MSW was 0.153 kg CO 2/kg MSW. The amount of GHG per unit of electricity generated by the combustion of MSW was 250 g CO 2/ kWh e. It was found that 640 g CO 2/kWh e by replacing coal by MSW and 470 g CO 2/kWh e can be avoided by replacing oil by MSW.
|
|
| 8. |
- Kyprianidis, Konstantinos G., et al.
(author)
-
Thermo-Fluid Modelling for Gas Turbines-Part I: Theoretical Foundation and Uncertainty Analysis
- 2009
-
In: ASME TURBO EXPO 2009 Proceedings, GT2009-60092.
-
Conference paper (peer-reviewed)abstract
- In this two-part publication, various aspects of thermo-fluidmodelling for gas turbines are described and their impact onperformance calculations and emissions predictions at aircraftsystem level is assessed. Accurate and reliable fluid modellingis essential for any gas turbine performance simulation softwareas it provides a robust foundation for building advanced multidisciplinarymodelling capabilities. Caloric properties forgeneric and semi-generic gas turbine performance simulationcodes can be calculated at various levels of fidelity; selection ofthe fidelity level is dependent upon the objectives of thesimulation and execution time constraints. However, rigorousfluid modelling may not necessarily improve performancesimulation accuracy unless all modelling assumptions andsources of uncertainty are aligned to the same level. Certainmodelling aspects such as the introduction of chemical kinetics,and dissociation effects, may reduce computational speed andthis is of significant importance for radical space explorationand novel propulsion cycle assessment.This paper describes and compares fluid models, based ondifferent levels of fidelity, which have been developed for anindustry standard gas turbine performance simulation code and an environmental assessment tool for novel propulsion cycles.The latter comprises the following modules: engineperformance, aircraft performance, emissions prediction, andenvironmental impact. The work presented aims to fill thecurrent literature gap by: (i) investigating the commonassumptions made in thermo-fluid modelling for gas turbinesand their effect on caloric properties and (ii) assessing theimpact of uncertainties on performance calculations andemissions predictions at aircraft system level.In Part I of this two-part publication, a comprehensiveanalysis of thermo-fluid modelling for gas turbines is presentedand the fluid models developed are discussed in detail.Common technical models, used for calculating caloricproperties, are compared while typical assumptions made influid modelling, and the uncertainties induced, are examined.Several analyses, which demonstrate the effects of composition,temperature and pressure on caloric properties of workingmediums for gas turbines, are presented. The working mediumsexamined include dry air and combustion products for variousfuels and H/C ratios. The errors induced by ignoringdissociation effects are also discussed.
|
|
| 9. |
- Kyprianidis, Konstantinos G., et al.
(author)
-
Thermo-Fluid Modelling for Gas Turbines-Part II : Impact on Performance Calculations and Emissions Predictions at Aircraft System Level
- 2009
-
In: ASME TURBO EXPO 2009 Proceedings, GT-2009-60101. ; , s. 483-494
-
Conference paper (peer-reviewed)abstract
- In this two-part publication, various aspects of thermo-fluidmodelling for gas turbines are described and their impact onperformance calculations and emissions predictions at aircraftsystem level is assessed. Accurate and reliable fluid modellingis essential for any gas turbine performance simulation softwareas it provides a robust foundation for building advanced multidisciplinarymodelling capabilities. Caloric properties forgeneric and semi-generic gas turbine performance simulationcodes can be calculated at various levels of fidelity; selection ofthe fidelity level is dependent upon the objectives of thesimulation and execution time constraints. However, rigorousfluid modelling may not necessarily improve performancesimulation accuracy unless all modelling assumptions andsources of uncertainty are aligned to the same level. Certainmodelling aspects such as the introduction of chemical kinetics,and dissociation effects, may reduce computational speed andthis is of significant importance for radical space explorationand novel propulsion cycle assessment.This paper describes and compares fluid models, based ondifferent levels of fidelity, which have been developed for anindustry standard gas turbine performance simulation code and an environmental assessment tool for novel propulsion cycles.The latter comprises the following modules: engineperformance, aircraft performance, emissions prediction, andenvironmental impact. The work presented aims to fill thecurrent literature gap by: (i) investigating the commonassumptions made in thermo-fluid modelling for gas turbinesand their effect on caloric properties and (ii) assessing theimpact of uncertainties on performance calculations andemissions predictions at aircraft system level.In Part II of this two-part publication, the uncertaintyinduced in performance calculations by common technicalmodels, used for calculating caloric properties, is discussed atengine level. The errors induced by ignoring dissociation areexamined at 3 different levels: i) component level, ii) enginelevel, and iii) aircraft system level. Essentially, an attempt ismade to shed light on the trade-off between improving theaccuracy of a fluid model and the accuracy of a multidisciplinarysimulation at aircraft system level, againstcomputational time penalties. The results obtained demonstratethat accurate modelling of the working fluid is not alwaysessential; the accuracy/uncertainty for an overall engine modelwill always be better than the mean accuracy/uncertainty of the individual component estimates as long as systematic errors arecarefully examined and reduced to acceptable levels to ensureerror propagation does not cause significant discrepancies.Computational time penalties induced by improving theaccuracy of the fluid model as well as the validity of the idealgas assumption for future turbofan engines and novelpropulsion cycles are discussed.
|
|
| 10. |
- Granström, Karin
(author)
-
Emissions of volatile organic compounds from wood
- 2005
-
Doctoral thesis (other academic/artistic)abstract
- The central aim of this thesis is to support the efforts to counteract certain environmental problems caused by emissions of volatile organic compounds. The purpose of this work was (1) to develop a method to establish the amount of emitted substances from dryers, (2) to determine the effect of drying medium temperature and end moisture content of the processed material on emissions of monoterpenes and other hydrocarbons, (3) to examine the emissions of monoterpenes during production of pellets, and (4) to examine the natural emissions from forests with an eye to implications for modelling. The measurement method (1) resolves the difficulties caused by diffuse emissions, and also solves the problems associated with high moisture content of the drying medium. The basic idea is to use water vapour to determine the exhaust flow, while a dry ice trap is used both to preconcentrate emitted volatile organic compounds and to determine the moisture content of the drying medium. The method as used in this paper has an uncertainty of 13% using a 95% confidence interval. Emissions from a spouted bed (2) in continuous operation drying Norway spruce sawdust at temperatures of 140°C, 170°C or 200°C was analysed with FID and GC-MS. When the sawdust end moisture content was reduced below 10%wb, emissions of terpenes and volatile organic compounds per oven dry weight increased rapidly. Increased temperature of the drying medium increased the amounts of emitted monoterpenes when sawdust moisture content was below the fibre saturation point. Examination of sawdust and wood pellets from different pellets producers (3) revealed that most of the terpene emissions happened during the drying step, with rotary dryers causing higher emissions than steam dryers. Almost all of the volatile terpenes remaining in wood after drying were released during pelleting. When sawdust with higher moisture content was used in the pellets press, the terpene emissions were increased. Terpenes emitted naturally from vegetation can have an adverse environmental impact. Factors affecting terpene emissions from tree species in Sweden were reviewed (4). Models for prediction of terpene fluxes should include not only temperature but also light intensity, seasonal variation, and a base level of herbivory and insect predation. Prediction of high concentrations of ambient terpenes demand sufficient resolution to capture emission peaks e.g. those caused by bud break.
|
|
