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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Development of an electric heat pump for domestic use

Crossman, D. R. January 1986 (has links)
This thesis records the design and development of an electrically driven, air to water, vapour compression heat pump of nominally 6kW heat output, for residential space heating. The study was carried out on behalf of GEC Research Ltd through the Interdisciplinary Higher Degrees Scheme at Aston University. A computer based mathematical model of the vapour compression cycle was produced as a design aid, to enable the effects of component design changes or variations in operating conditions to be predicted. This model is supported by performance testing of the major components, which revealed that improvements in the compressor isentropic efficiency offer the greatest potential for further increases in cycle COPh. The evaporator was designed from first principles, and is based on wire-wound heat transfer tubing. Two evaporators, of air side area 10.27 and 16.24m2, were tested in a temperature and humidity controlled environment, demonstrating that the benefits of the large coil are greater heat pump heat output and lower noise levels. A systematic study of frost growth rates suggested that this problem is most severe at the conditions of saturated air at 0oC combined with low condenser water temperature. A dynamic simulation model was developed to predict the in-service performance of the heat pump. This study confirmed the importance of an adequate radiator area for heat pump installations. A prototype heat pump was designed and manufactured, consisting of a hermetic reciprocating compressor, a coaxial tube condenser and a helically coiled evaporator, using Refrigerant 22. The prototype was field tested in a domestic environment for one and a half years. The installation included a comprehensive monitoring system. Initial problems were encountered with defrosting and compressor noise, both of which were solved. The unit then operated throughout the 1985/86 heating season without further attention, producing a COPh of 2.34.
2

Strategic stakeholder dialogue and social sustainability indicator development for nuclear decision-making in Anglesey, North Wales

Parry, Ioan Mihangel January 2017 (has links)
As new nuclear power developments are proposed for the UK over the coming decades, it is important that public engagement and decision-making processes for these developments are carried out as effectively and sustainably as possible to benefit both current and future generations and mitigate negative social impact and conflict, particularly at the local scale. Alternative approaches are required to those employed historically, which were often expert-led, public-excluding, and vulnerable to extensive critique and opposition, particularly for large-scale and often contentious industrial or technological developments. The research employs a mixed-method approach to engage with different social groups in Anglesey, North Wales, a predominantly rural island where the Wylfa Newydd Nuclear Power Station is proposed to be developed. Quantitative and qualitative techniques are employed to study intra-community social priorities, both generally and development- related, in order to highlight important social sustainability issues for a potential development. The four social groups that participated in this research included two secondary school student groups (YUB and YSTJ Students) and two adult groups (YSTJ Teachers and CTGYM Farmers), reflecting multi- generational representation. Similarities and differences between groups are highlighted which suggests that engagement with ‘the public’ may be more effective if a strategic, social group and priority-based approach was employed, working with existing social collectives at the local scale. The Social Group Dialogue Strategy is proposed to facilitate this approach. I argue that both engagement and decision-making should reflect the pluralism present within local communities, and thereby enhance the effectiveness of stakeholder engagement and legitimacy of decision-making processes. I also argue that deliberative dialogue focussed on understanding social priorities can facilitate indicator development and effective engagement with local communities. Concepts of fairness and justice, such as procedural justice, are identified and discussed in the context of strategic decision-making, sustainability indicator development and dialogue-based engagement with public stakeholders.
3

Understanding the design of energy interventions to reduce end-user demand in organisational and domestic environments

Foster, Derek January 2017 (has links)
Energy demand is on the rise globally due to unchecked factors such as population growth, lifestyle choices, and the industrialization of developing countries. Governments are investing in technologies for efficient and renewable energy in an attempt to secure energy for the future over current dependencies on fossil fuels, but the development costs are high, and the rate of developed technologies is projected to fall far short of meeting global requirements. Overshadowing this growing appetite for energy is the global issue of climate change, igniting the scientific and humanitarian debate over the use of fossil fuels and a need for renewable energy, presenting a societal problem of generating clean, sustainable and secure energy for future generations. As part of understanding how society can make positive changes to daily practices around energy use, many governments have turned to behaviour change, or ‘nudge’ units, that research work on changing energy consumption behaviours. The importance of this is underlined by a focus on reducing end-user energy demand (EUED) by providing contextual energy feedback, interwoven with behaviour change strategies, in both residential and organizational sectors. EUED in large organisations and small-medium enterprises (SMEs) accounts for a significant proportion of a nation’s energy requirements. In Europe, the services sector saw a 34% growth in EUED in the period 1990-2012, with computers and other appliances in the office substantially contributing to this. In the UK, for example, 13% of total energy consumed in 2011-2012 was within the services sector, which accounts for services and business, while the residential sector consumed 30% of total consumption. Given a lack of academic HCI research in the organisational energy intervention space when comparted to domestic, the principle research undertaken in this thesis was to understand employee energy consumption practices and attitudes in the workplace, through a combination of qualitative enquiry and analysis. Additionally, alternative forms of feedback such as aversive stimuli are often ignored in the HCI literature, with favour focused on positive feedback alone as a means for behaviour change. The work in this thesis presents findings on the design implications and considerations that inform the design of in-the-field organisational energy interventions that integrate feedback and antecedent behaviour contingencies. Additionally, research is undertaken in understanding the design of aversive feedback as part of domestic energy interventions. A significant contribution is made to the HCI sustainability literature on understanding the workplace energy intervention design space, and a contribution made on how aversive feedback can in fact be a useful and engaging method for the domestic environment.
4

A description of the electricity system in Spain since 2005 and the economic potential for renewable energy technologies

Izquierdo-Millan, Javier 24 January 2014 (has links)
The energy system in Spain can be characterized as being high energy intensive when compared to the rest of Europe and because of its high dependence on imported resources (around 84%). The focus of this document is to explore a novel approach to describe, as part of this energy system, the electricity system in Spain since 2005 and the economic potential for renewable energy technologies (RET) to replace the electricity generated from fossil resources by 2050. The heart of the design and implementation of any RET policy should be the reduction or elimination of fossil fuel dependency. This document aims at describing the evolution of the Spanish electricity system in the last decade, and addressing the possible influence of certain factors in the design and implementation of the electricity system by using modern modeling technologies to evaluate the potential of RET. This will represent a novel approach to bridge the results from modeling technologies to policy makers. To ensure the credibility and reliability of the data researched, validation criteria has been used which includes the accuracy of information, the content (whether factual or opinion), time (limited to certain periods), format (validity of internet sources, journals, etc), authority (reputable authors and sources), objective reasoning, currency and links to other resources, and the quality of writings and its review among others. The proposed research approach follows a methodology where the first step is to understand the electricity system in Spain, followed by the definition of the model of interest (optimization models) and the design of three different scenarios (Business as Usual, FIT and High fossil prices) for the evaluation of the potential of RET, finishing with the analysis of the results from the model and data collected from the perspectives of what has been done in previous RET policies and plans, and the possible influence of factors such as organizations and corporations on those policies and plans. The results obtained from the model are analysed and compared to the Business as Usual scenario. The amount of electricity generated from fossil resources and to be replaced by RET is calculated using the scenarios, as well as the evolution of primary energy, imports, final energy consumptions and CO2 emissions. In order to test the applicability of this approach, the results of the model have been compared with the current situation of the Spanish electricity system. Calculations using capacity factors of the RET and their share in the current electricity generation are performed in order to identify the final amount of power (MW) to be installed in order to replace the electricity generated (GWh) by fossil resources by 2050. Based on the conclusions, RET has the potential to replace the generation of electricity from fossil fuels but improvements in the efficiency of RET will be needed. In addition, it is recommended that significant considerations in RET policy like the energy and electricity systems should be a strategic component of the Spanish policy system, be done in order to set the Spanish electricity system in a more sustainable path .
5

Motivations et barrières à l'adoption des technologies solaires par les ménages marocains : quels enseignements pour les politiques publiques ? / Motivations and barriers to solar technologies adoption by moroccan households : lessons for the public policies

Juidette, Mehdi 11 December 2015 (has links)
Le Maroc, en tant que pays non producteur d’énergie fossile, subit de plein fouet les fluctuations des prix des produits entrant dans la production de l’énergie. Afin de créer une indépendance énergétique, il a lancé en 2007 un programme qui vise à produire de l’énergie à partir de sources alternatives aux sources fossiles. Dans notre thèse, nous essayons à travers une démarche qualitative de comprendre les motivations et également les barrières qui ont une influence directe sur la décision d’adoption des technologies solaires par les ménages marocains. Pour ce faire nous nous sommes appuyés sur un cadre théorique ayant été utilisé dans plusieurs contextes pour comprendre notre objet de recherche qui est la diffusion d’une innovation technologique. Après avoir présenté une revue de littérature sur les différents modèles de diffusion, nous avons réalisé une étude comparative entre trois pays ayant déjà entamé l’expérience du solaire voire même devenus pionniers en la matière et le Maroc. Par la suite, nous avons réalisé une approche qualitative en deux temps. Nous avons réalisé des entretiens d’experts avec les principaux acteurs de la filière solaire au Maroc. Ensuite nous avons organisé des groupes de discussion avec des ménages ayant adopté ou non des technologies solaires. Cette approche nous a permis d’identifier des axes de travail importants sur lesquels le pouvoir public devrait agir. Nous avons constaté que le facteur coût joue un rôle central dans la décision d’achat de ces technologies, de même que l’accès à l’information, d’où l’importance d’une bonne communication autour des possibilités offertes par le solaire / Morocco is not a country that produces a fossil energy. He undergoes the price fluctuations of the products used in the energy production. In order to to reduce its energy bill, he started in 2007 an ambitious program which aims to produce energy starting from alternative sources. He seeks to produce 42% of his energy needs starting from renewable energies including 14% from the solar one. In our thesis, we try through a qualitative approach to understand the motivations and also the barriers which have a direct influence on the decision of adoption of solar technologies by Moroccan households. After having presented a review of literature on the various models of diffusion, we carried out a comparative study between three countries having already started the experiment of solar and even become pionniers on the matter and Morocco. Thereafter, we carried out a qualitative approach in two times. We carried out talks with the main actors of the solar sector in Morocco. Then we organized focus groups with households having adopted or not solar technologies. This approach enabled us to identify important work axes on which the public authority should act. We noted that the factor cost plays a central role in the decision of purchase of these technologies. Just as the access to the information which can be sometimes erroneous from where importance of a good communication around the opportunities given by the solar technologies
6

Life performance assessment methodologies for combined solar energy technologies : a case study on system parts in nordic climates

Stojanovic, Bojan January 2007 (has links)
<p>The main questions concerning energy technologies today are their economical and environmental impacts. These entities are (at the present) assessed on the basis that operations proceed as newly installed/designed systems, during an assumed working life period. While this is the common way of perceiving energy systems, performance-over-time will change as an effect of (e.g. material) degradation and not solely of different operation scenarios. How and to what extent, is the question that needs assessing in order to evaluate if these changes will jeopardise the intended system performance requirement. In turn, this pro-active assessment and analysis is in line with today’s performance based directives, laws, regulations and concepts; of which the working life is an essential part.</p><p>The main context of the thesis, is a contribution to the Research and Development (R&D) topic on life performance of energy technologies, with papers on a literature review and case study on two system parts: <i>solar collector and ground heat exchanger (borehole)</i>; within the energy technology area of combined solar energy technologies/systems utilised in buildings. The thesis specifically presents a general description of requirements on constructed works and their material, components and systems. It also gives an insight to the energy technology R&D and engineering sector, regarding durability and service life assessment methodologies; and also to the durability of constructed works sector, regarding the needs for assessing material degradation in relation to system performance. The case studies presented in the thesis, show how durability of energy technologies may be sought-after, as well as specific knowledge and useful tools, methodologies and test setups for assessing long-term performance of combined solar energy technologies (in this case a solar-assisted heat pump system utilising a building integrated Unglazed Solar Collector and energy storage).</p><p>The utilisation of solar collectors and heat pumps (primarily for space and domestic tap water heating) has rapidly increased in Sweden during the last decades. Sweden has today the largest heat pump market in Europe. During recent years, there has also been an increased interest in heating systems that combine heat pumps with solar collectors (glazed and unglazed) and energy storages; with the aim of attaining a system that provides higher energy and greater economical performances than individual solar collector or heat pump systems. If these systems are to be successful they must be economically feasible; placing emphasis on the cost, durability and performance of the system.</p><p>The main issue on life performance of energy technologies is how and to what extent, performance reduction in individual materials and components influences the overall system performance; as the essence of energy system sustainability is system performance.</p>
7

Going solar in paradise : solar water heaters on the island of Hawaii

Murray, Julie Marie 20 November 2013 (has links)
Energy efficient technologies and renewable energy technologies are becoming less of a novelty in the American energy mix. These technologies offer the promise of a decreased dependence on foreign oil, considerable savings of energy bills, and protections for the environment. Despite the many potential benefits, these technologies face many barriers to adoption. The lack of renewable energy technologies and energy efficient technologies is particularly damaging in the State of Hawaii, where 90% of energy needs are met with imported fossil fuels. This report focuses on the current energy policies in Hawaii and the barriers to the incorporation of renewable energy technologies and energy efficient technologies, specifically solar water heaters. / text
8

The contribution of renewable energy technologies to sustainable community development in Rusitu Valley, Zimbabwe

Mavindidze, Zororo January 2012 (has links)
Magister Artium (Development Studies) - MA(DVS) / This exploratory study is based on the case of the Rusitu Valley, a low income rural community in Zimbabwe. Data was collected using largely qualitative methods and quantitative methods were used to obtain supportive descriptive statistics. Information elicited from focus group discussions conducted with members of the Rusitu Valley community as well as responses obtained from a brief structured questionnaire were used to abstract the Rusitu Valley as a complex adaptive system. Input from in-depth interviews with government representatives in energy policy, local government and non-governmental organisations as well as a review of secondary sources was used to support the analysis and confirm the contextual validity of the study. This study revealed that there is intimate connection between renewable energy technologies and sustainable community development. A key finding was that the contribution of renewable energy technologies in Rusitu Valley is mostly towards the economic dimensions of the community and is relatively limited with regard to social and environmental dimensions. Therefore, this study concluded that renewable energy technologies have not sufficiently contributed towards sustainable community development in the Rusitu Valley. This study also found that the contribution of renewable energy technologies is constrained not only by internal limitations but also external factors. A conclusion drawn from this study was that effective contribution of renewable energy technologies towards social, economic and environmental facets can be enhanced through mainstreaming of renewable energy in policy and planning, as well strengthening institutions and local capacity which would have the overall effect of sustainable community development in low income communities
9

Critical analysis of the right of access electricity for the destitute in South Africa : issues and challenges

Moshoeu, Lesiba Benedict January 2017 (has links)
Thesis (M. Dev.) -- University of Limpopo, 2017. / This mini-dissertation examines and articulates the right to access electricity for the destitute in South Africa. Further, this mini-dissertation finds that high tariffs on electricity impede the accessibility and realisation of electricity as a human basic need. As a result, this mini- dissertation submits that accessibility and affordability of electricity as human basic need are compromised. Subsequently, the destitute are unable to afford and access electricity as encapsulated in the legislation. Therefore, this mini- dissertation submits that there must be investment in energy technologies to meet electricity demands. Furthermore, this mini-dissertation submits that there should be radical deployment of renewable energy in order to provide sufficient and affordable electricity to all, including the destitute. The investments in the building of the new power stations (Medupi, Kusile and Ingula) is welcomed by this mini- dissertation since it will solve the load shedding challenges which has affected South Africans and threaten the economic growth. Keywords: Energy, electricity, high tariffs, South Africa, destitute and accessibility.
10

Life performance assessment methodologies for combined solar energy technologies : a case study on system parts in nordic climates

Stojanovic, Bojan January 2007 (has links)
The main questions concerning energy technologies today are their economical and environmental impacts. These entities are (at the present) assessed on the basis that operations proceed as newly installed/designed systems, during an assumed working life period. While this is the common way of perceiving energy systems, performance-over-time will change as an effect of (e.g. material) degradation and not solely of different operation scenarios. How and to what extent, is the question that needs assessing in order to evaluate if these changes will jeopardise the intended system performance requirement. In turn, this pro-active assessment and analysis is in line with today’s performance based directives, laws, regulations and concepts; of which the working life is an essential part. The main context of the thesis, is a contribution to the Research and Development (R&amp;D) topic on life performance of energy technologies, with papers on a literature review and case study on two system parts: solar collector and ground heat exchanger (borehole); within the energy technology area of combined solar energy technologies/systems utilised in buildings. The thesis specifically presents a general description of requirements on constructed works and their material, components and systems. It also gives an insight to the energy technology R&amp;D and engineering sector, regarding durability and service life assessment methodologies; and also to the durability of constructed works sector, regarding the needs for assessing material degradation in relation to system performance. The case studies presented in the thesis, show how durability of energy technologies may be sought-after, as well as specific knowledge and useful tools, methodologies and test setups for assessing long-term performance of combined solar energy technologies (in this case a solar-assisted heat pump system utilising a building integrated Unglazed Solar Collector and energy storage). The utilisation of solar collectors and heat pumps (primarily for space and domestic tap water heating) has rapidly increased in Sweden during the last decades. Sweden has today the largest heat pump market in Europe. During recent years, there has also been an increased interest in heating systems that combine heat pumps with solar collectors (glazed and unglazed) and energy storages; with the aim of attaining a system that provides higher energy and greater economical performances than individual solar collector or heat pump systems. If these systems are to be successful they must be economically feasible; placing emphasis on the cost, durability and performance of the system. The main issue on life performance of energy technologies is how and to what extent, performance reduction in individual materials and components influences the overall system performance; as the essence of energy system sustainability is system performance. / QC 20101117

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