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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.
121

Analise da evolução de ações na difusão do aquecimento solar de agua para habitações populares : estudo de caso em Contagem - MG / Evolution actions difusion of solar water heating technology for low-cost house : study case Contagem - MG

Fantinelli, Jane Tassinari 22 February 2006 (has links)
Orientador: Jose Tomaz Vieira Pereira, Elizabeth Marques Duarte Pereira / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-06T09:17:29Z (GMT). No. of bitstreams: 1 Fantinelli_JaneTassinari_D.pdf: 4761109 bytes, checksum: 24169f2686e7a2a24d1d355b5ef3e0d1 (MD5) Previous issue date: 2006 / Resumo: Os programas para a redução da pobreza e para o acesso das populações às condições básicas para uma boa qualidade de vida devem contemplar soluções que considerem os avanços tecnológicos e os benefícios da produtividade e da eficiência energética. O uso de sistemas termossolares (coletores solares) como forma de substituir a eletricidade para o aquecimento de água já foi uma solução adotada em diversos países do mundo, entre a Primeira e a Segunda guerras mundiais e no primeiro e segundo choques do petróleo. Hoje se insere como uma alternativa que causa menores danos ambientais e traz retorno financeiro para as populações de baixa renda, pela economia de energia elétrica. A eficiência energética alcançada com coletores solares dimensionados para pequenos volumes de água para o consumo no banho e a adaptação das famílias com a tecnologia foram constatados através de estudo de caso realizado no Bairro Sapucaias, em Contagem (MG). A economia com a redução da conta de energia se reflete na aquisição de eletrodomésticos e também nas aspirações e desejos que sinalizam novas perspectivas de futuro, como a posse de microcomputador. A investigação sobre as ações dos diversos agentes envolvidos na disseminação do uso de sistemas termossolares para os segmentos de interesse social no Brasil mostra que os sucessivos programas, planos e metas, estabelecidos para se incorporarem em políticas estratégicas de desenvolvimento do país, não foram implementados. A ausência de um planejamento energético específico para a parcela da população (49,7 milhões de pessoas - 27,6% da população) que ganha até 2 salários mínimos mostra que as políticas públicas deverão ser direcionadas para promover estratégias que considerem planos de longo prazo e de grande abrangência social. Para essa parcela, o gasto com energia elétrica para banho representa 14% a 23% de sua renda mensal. Ações que promovam o uso de tecnologias eficientes para o benefício de grandes parcelas da população devem estar inseridas no planejamento estratégico de desenvolvimento na nação, alinhadas com todas as demais estruturas: econômicas, energéticas, ambientais, educacionais / Abstract: The programs for reduction of poverty and for providing people with access to the basic conditions for a good life quality should include solutions that take into account technological advances and the benefits of productivity and energyc efficiency. The use of solar collectors to replace electricity in water heating has already been adopted in several countries of the world, between the First and Second World Wars and on the first and second oil crises. Today it appears as an alternative that causes less environmental harm and brings financial gains to low income populations through electric energy savings. The energyc efficiency attained with solar collectors designed for small water volumes for consumption in bathing and the families¿ adaptation to this technology have been verified by means of a case study conducted at the Sapucaias district, in Contagem, MG. The savings through the reduction of the energy bill are witnessed by the acquisition of electric and electronic goods and also by the aspirations and desires denoting new perspectives about the future, like possessing a personal computer. An inquiry on the actions of the several agents involved in the diffusion of the use of solar collectors among classes of lowcost houses in Brazil reveals that the successive programs, plans and goals proposed for incorporation in strategic development policies for the country have not been executed. The absence of an energy planning specific to the significant parcel of Brazilian population (49.7 million people, 27.6% of its population) earning up to 2 minimum wages shows that public policies should be directed to the promotion of strategies founded on long term planning of large social reach. For this, parcel the expenditure with electric energy for bathing represents approximately 14 to 23 percent of their monthly income. The actions promoting the use of efficient technologies for the benefit of great parcels of population should be inserted in the strategic planning for the nation¿s development, in line with all its other structures: economic, energetic, environmental, educational / Doutorado / Doutor em Planejamento de Sistemas Energéticos
122

Modelagem de um secador solar de produtos agrícolas com sistema de armazenagem de energia térmica / Modeling of a solar dryer for agricultural products with thermal energy storage system

Luciano Roberto da Silveira 26 February 2016 (has links)
Nos países em desenvolvimento, como o Brasil, a secagem de produtos agrícolas com uso de secador solar representa uma alternativa promissora de baixo custo, reduzindo perdas e agregando valor aos produtos. Porém, devido à natureza periódica da radiação solar e das condições do tempo, nem sempre é viável sua utilização. Dessa forma, o objetivo do trabalho foi a modelagem de um sistema auxiliar de armazenagem de energia térmica (SAET) em um secador solar, cuja finalidade é armazenar energia durante o dia para ser utilizada conforme necessário. Com base em registros de temperatura e umidade relativa, ambas do ar, de um secador solar, foi feito um estudo da termodinâmica dos processos envolvidos, a fim de propor meios para o dimensionamento do SAET. Foram explorados a estimativa do fluxo de massa de ar no secador, a modelagem da temperatura em função da radiação, e o dimensionamento para diferentes modos de operação do SAET, considerando o sistema ideal. Este dimensionamento tratou tanto do caso de fornecimento contínuo de fluxo de água preaquecida, como de uso de automação para controlar o fluxo. A estimativa de fluxo de ar no secador se aproximou de valores típicos encontrados na literatura. O dimensionamento do sistema, embora considerado ideal, mostra que a utilização do SAET melhora o desempenho do secador, servindo como parâmetro para melhor compreender o comportamento das variáveis durante seu funcionamento. / In developing countries such as Brazil, drying of agricultural products by using solar dryer is a promising low cost alternative to reduce losses and add value to products. However, due to periodic behavior of solar radiation and weather conditions, the use of solar drier is not always feasible. The objective of this study is to model an auxiliary thermal energy storage (ATES) in a solar drier, aiming to store energy during the day to be used as needed. Based on both air temperature and relative humidity records of a solar dryer, the thermodynamics of the underlying processes was studied in order to propose means for designing the ATES. It was addressed the estimative of the air mass flow in the dryer, the modeling of the temperature as a function of the radiation, and the designing of the ATES for different modes of operation, considering the optimal system. The designing dealt with both the continuous supply of preheated water flow and the use of automation for controlling the flow. The estimated air flow in the dryer approached typical values found in the literature. The designing of the system, although considered ideal, shows that the use of ATES improves the drying performance, serving as a parameter to better understand the behavior of variables during operation.
123

Návrh řízení a regulace tepelného systému u RD s využitím systémové instalace LOXONE / Using LOXONE system installation for Design control and regulation the heating system in house

Novák, Michael January 2017 (has links)
The diploma thesis deals with the division of the system installation and gives an overview of electrical appliances and heating system. It focuses on the Loxone system installation. The main part is the project documentation of wiring, programming the control of a family house and regulation of the solar thermal system for heating water and the heating system control. It also includes a simple economic evaluation of the proposed solar system.
124

Optimalizace provozu solárního systému určeného k ohřevu TUV školní jídelny / Optimization of the solar system designed for DHW school canteens heating

Doskočil, Filip January 2016 (has links)
Masters’s thesis describes the use of solar energy for solar thermal systems used for domestic hot water heating. It is about the size of the incident solar radiation on Earth. Distributes various types of solar collectors for water heating. It deals with the monitoring, remote management of this system and the design of optimal control used in this area.
125

Kvantifikace energetických ztrát fototermického systému ohřevu TUV při napájení fotovoltaikou / Quantification of energy loss in photothermic system of hot water supply in photovoltaics

Havlíček, Lukáš January 2014 (has links)
This masters’s thesis is about quantify of energy losses in the solar system for heating of hot water by energy from photovoltaics. During the April in year 2014 will be realized a practical data collection on the real system. Then, based on these measurements, calculations will be performed.
126

Solární chladicí systém / Solar cooling system

Klusák, Jan January 2009 (has links)
The work is focused on the issue of cold production using absorbent circulation driven by thermal energy solar collectors recovered. The work can be divided into several main parts. In the first part of this work is given an overview of the possible principles of solar cooling system. In the next section followed by a description of the principle of absorption cycles. In the practical part is solved design proposal absorption refrigeration units with a cooling power of 6 kW. This is followed by a proposal to link solar cooling system with the absorption unit. Final section is made of basic technical-economic comparison of solar refrigeration unit with the compressor refrigeration units.
127

Návrh a porovnání otopných soustav s různými zdroji tepla pro vytápění rodinného domu / Design and comparison of a space heating systems with different heat sources in family house

Kamenský, Petr January 2010 (has links)
Diploma thesis deals with design and comparison of heating systems. In diploma thesis is designed system with gas condensing boiler, system with heat pump and system with gas condensing boiler for heating and solar collectors for heating of hot water. Content of this thesis is calculation of house heat loss, design of radiators, design of heat systems including a check of protective components, regulation with the help of thermostatic radiator valve, calculation of economical evaluation and creation of design documentation. Design is made for systems with unified temperature fall 55/45. For the variation with heat pump is computed a possibility of using the heat pump as an univalent or bivalent heat source. In the analysis of costs is considered a usage of natural gas for heating and warming of hot water with a condensing boiler, annual consumption of electric energy for operation of electrical appliances in household, consumption of electric energy for operation of heat pump for heating and warming of hot water and consumption of electric energy for warming of hot water in case of system with solar collectors. In the final evaluation a pay-off period is determined.
128

Optimalizace provozu solárního systému určeného k ohřevu TUV školní jídelny / Optimization of the solar system designed for DHW school canteens heating

Doskočil, Filip January 2016 (has links)
Masters’s thesis describes the use of solar energy for solar thermal systems used for domestic hot water heating. It is about the size of the incident solar radiation on Earth. Distributes various types of solar collectors for water heating. It deals with the monitoring, remote management of this system and the design of optimal control used in this area.
129

Termisk energilagring i borrhål : En studie av borrhålets temperaturinverkan på värmepumpens värmefaktor / Borehole thermal energy storage : A study of the boreholes temperature impact on the heat pump's coefficient of performance

Raschke, Marcus, Peterson, Victor January 2014 (has links)
Sverige har en hög andel installerade bergvärmepumpar, som är en typ av vätska-vatten värmepump. Ett problem som finns för befintliga bergvärmesystem är att berget med tiden kyls ned då returslangen till borrhålet konstant levererar kyla till berget. Till följd av detta mister systemet en betydande del av sin verkningsgrad samtidigt som det i extrema fall kan leda till permanent isbildning i borrhålet. Ett sätt att motverka detta problem är att tillämpa termisk energilagring i bergvärmesystemets borrhål. Den internationella benämningen för denna teknik är ”Borehole Thermal Energy Storage, BTES”. Rapporten har behandlat en friliggande enplansvilla med ett befintligt bergvärmesystem som tillämpar termisk energilagring i bergvärmesystemets borrhål med solvärme. Två beräkningsfall har gjorts och resultatet från simuleringarna i en upprättad beräkningsmodell visar att en temperaturhöjning i borrhålet inte alltid innebär en årlig energibesparing. Vid varje grads temperaturhöjning sker en ökning av värmepumpens COP med ca 1,85 % enligt ett linjärt samband för höga temperaturdifferenser över värmepumpen. Detta motsvarar en kostnadsbesparing på 1,02 %/°C. Detta gäller för normala förhållanden med en framledningstemperatur för tappvarmvatten och rumsvärmare på 55 ⁰C. Med en högre energiförbrukning finns alltså större besparingar att göra. Vid mycket låga temperaturdifferenser mellan förångare och kondensor sker dock större procentuella förändringar, vilket medför att lågtemperatursystem kan bidra till en större energibesparing. I normalfallet är dessa system svåra att räkna hem för småhus. För en god lönsamhet krävs en optimerad systemlösning och effektiv styrning av cirkulationspumpar och andra samspelande komponenter med en PLC. I framtiden kommer dock sannolikt värmepumparnas mekaniska verkningsgrad att öka med bättre teknik och även energipriset som följd av politiska beslut, tillgång etc. Detta innebär att varje besparad kilowattimme kommer att bli mer värd. / Sweden has a high proportion of installed geothermal heat pumps, which are a type of liquid -water heat pump. One problem that exists for existing geothermal heating systems is that the rock in time cool down when the return hose to the borehole constantly supply cooling to the rock. As a result of this the system loses a significant portion of their efficiency while in extreme cases has led to the permanent ice in the borehole. One way to counter this problem is to apply thermal energy storage in the geothermal heating systems borehole. The international term for this technique is "Borehole Thermal Energy Storage, BTES". This report has analyzed a detached single storey house with an existing geothermal heating system utilizing thermal energy storage in the geothermal heating systems borehole with solar heating. Two calculation cases has been made and the results of the simulations in an established computational model shows that an increase in temperature in the borehole does not always result in an annual energy savings. Each degree of increased temperature is an increase in the heat pumps COP of 1.85 %, according to a linear relationship for high temperature differences across the heat pump. This results in a cost saving of 1.02 %/°C. This applies to normal conditions with a radiator temperature at 55 ⁰ C. With higher energy consumption can greater savings be made. At very low temperature differences between the evaporator and condenser is however larger percentage changes made, which means that low temperature systems can lead to greater energy savings. Typically, these systems are difficult to recoup for small detached houses. For a good profitability requires an optimized system solution and efficient control of circulation pumps and other interacting components with a PLC. In the future the heat pump mechanical efficiency will probably increase with better technology and even energy prices as a result of political decisions, access, etc. This means that each spared kilowatt hour will be worth more.
130

Zero CO2 factory : Energikartläggning av industrier och ett exempel på hur noll utsläpp nås / Zero CO2 factory : An energy audit of industries and an example on how to reach zero emissions

Wannemo, John January 2019 (has links)
Industrin står för 32% av den globala energianvändningen och majoriteten av industrins utsläpp sker vid förbränning av fossila bränslen för värmeanvändning. Hälften av industrins värmeanvändning uppskattas vara i temperaturer upp till 400 °C vilket är lämpligt för värme från solfångare.Klädesindustrin står för 10% av de globala växthusgasutsläppen och majoriteten av de utsläppen sker vid textilproduktion och flera av textilindustrins processer är i temperaturintervall som kan använda värme från solfångare likt Absolicons T160.Data från energianvändning hos textilfabriker har samlats in och beräkningar på energianvändning och utsläpp har gjorts för erhållna data. Solfångarnas energiberäkningar har gjorts med hjälp av simuleringar från Absolicon applikation Field Simulator. En 3-stegs plan gjordes för 2 stora textilfabriker i Indien som visar hur de skulle kunna eliminera sina utsläpp från energianvändning.Kartläggningen visar att textilindustrin till stor del använder fossila bränslen och de 5 största textilfabrikerna i denna rapport visar en energifördelning mellan värme och el på 85% respektive 15%. Utsläppen per producerad massa varor i kg för de 5 fabrikerna uppskattas vara i snitt 6,1 kgCO2e vilket motsvarar en förbränning av 2,1 kg brunkol.De två stora textilfabriker i Indien samlade utsläpp från energianvändning redovisas vara 686 ktCO2e. Värmeanvändningen i fabrikerna sänks i 3-stegsplanen med 17% och fossila bränslen ersätts med värme från solfångare och biomassa. För att täcka 68% av det nya värmebehovet med värme från solfångare så behövs det solfångarfält med en termisk effekt på cirka 400 MW och en yta på cirka 1,3 km2. De resterande 32% av värmebehovet ska komma från förbränning av cirka 100 000 ton biomassa per år.Industrin har möjlighet att sänka stora delar av sina utsläpp genom att ersätta fossila bränslen i värmeanvändningen med till exempel värme från solfångare och biomassa. För att täcka stora delar av värmeanvändningen med solfångarfält behövs lediga ytor runt om och på fabrikerna. Fossila bränslen har i dagsläget ett lågt pris i förhållande till dess utsläpp och tillämpning av globala utsläppsrätter eller skatter bör appliceras för att påskynda omställningen till utsläppsfri energi och lägre utsläpp. / The industry sector accounts for 32% of the global energy usage where the majority of the energy is being used as heat. Most of the heat is generated by burning fossil fuels which leads to heat use being the largest source of emissions in the sector. About half of energy used as in the industries are in temperatures up to 400 °C which is suitable for heat provided by solar collectors.The apparel industry accounts for 10% of the global carbon emissions and multiple of the industry processes used in textile production are in temperature ranges reachable with solar collectors such as Absolicons T160.Energy data was collected from textile factories and calculations of energy usage and emissions was made. The calculations for solar collectors was made with Absolicons web application Field Simulator. A 3-step plan was created to demonstrate how two textile factories in India could reach zero CO2 emissions.The analysis shows that the textile industry’s majority of energy is being used from fossil fuels to generate heat where the 5 largest factories in this report average energy is 85% as heat and 15% as electricity. The emissions per produced mass of goods in kg is an average of 6,1 kgCO2e at these 5 factories which is comparable to burning 2,1 kg of black coal.The two large textile factories combined emissions from energy usage is reported to be 686 ktCO2e. In the 3-step plan the heat usage is reduced by 17% and heat from fossil fuels are replaced by heat from solar collectors and biomass. To cover 68% of the new energy demand it would require solar fields with a total thermal capacity of about 400 MW and an area of 1,3 km2. The remaining 32% of heat demand would be covered by burning 100 000 tonne of biomass per year.The conclusion is that he industry sector has a huge potential of reducing their emissions by replacing fossil fuels for generating thermal energy by thermal energy from e.g. solar collectors or biomass. It will require available spaces close to or on top of the factories to be able cover large portions of the heat demand with solar collectors. The current prices of energy from fossil fuels is low compared to their emissions and a global carbon market or taxes should be applied to accelerate the change to clean energy and lower emissions.

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