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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.
21

Méthode simplifiée d'évaluation de la performance énergétique utilisable en conception et alimentée par des données issues de politiques publiques de produit : application aux systèmes de chauffage de bâtiments / A simplified energy performance assessment method supporting system design and fed by EU product policy data : application to heating systems in buildings

Calero Pastor, Maria 07 February 2018 (has links)
La performance environnementale des produits influence largement la performance des systèmes. De plus, les systèmes présentent encore un potentiel d'économie d'énergie inexploité pour la performance environnementale globale, comparé aux produits individuels qui les composent.L'objectif de ce travail est de proposer une approche pour l'évaluation de performance énergétique de systèmes, en tenant compte d'information / de données livrées par les politiques européennes de produits (Directives Eco-conception et Étiquetage énergétique, Verdissement des marchés publics, Ecolabel Européen). L'hypothèse considérée ici est que les politiques environnementales des produits, qui ont été très utiles pour faciliter un système de notation homogène sur le marché européen des produits, peuvent également être avantageusement utilisées dans une démarche visant pour évaluer la performance énergétique des systèmes.Ce travail de recherche propose une méthode simplifiée pour soutenir la conception de systèmes de chauffage performants en utilisant les données des politiques environnentales de produits de l'Union Européenne, disponibles en phase de conception. Tout d'abord, une modélisation du système avec une approche "top-down" est utilisée pour prendre en compte les aspects système (conditions géographiques, caractéristiques du bâtiment, etc.). Deuxièmement, la performance énergétique du système est calculée à partir d'une approche "bottom-up", à partir de la performance des produits et des sous-systèmes composant le système. La méthode comporte 5 étapes divisées en deux phases principales: diagnostic du système initial et amélioration. La méthode est supportée par un outil de calcul original qui détermine les paramètres énergétiques (demande d'énergie, consommation d'énergie et rendement énergétique) au niveau du système en utilisant les données de performance telles que documentées par les politiques produits de l'Union Européenne. La méthode permet d'évaluer la performance d'un système de chauffage en définissant les systèmes les plus mauvais et les meilleurs possibles. La méthode est flexible et permet d'évaluer différentes configurations de produits et peut donc soutenir les activités de conception des systèmes de chauffage de bâtiment.La méthode est testée sur une étude de cas, la re-conception conception d'un système de chauffage existant d'une habitation dans le nord de l'Italie, incluant un système d'eau chaude sanitaire solaire et un système de chauffage des locaux. L'étude de cas démontre le potentiel d'amélioration du système de chauffage basé sur les résultats produits par la méthode, en aidant à sélectionner les produits actuellement disponibles sur le marché. En outre, sur la base de l'évaluation, plusieurs variantes de re-conception peuvent être proposées combinant différentes performances des produits qui composent les systèmes de chauffage. La thèse analyse également l'évolution des différentes approches adoptées par les politiques de produits de l'Union Européenne (approche produit, approche produit étendu et approche système). En particulier, le concept de "package" (ou produits combinés) défini dans les réglementations d'étiquetage énergétique des systèmes de chauffage est étudié en détail. L'étiquette du "package" du règlement 811/2013 est mise en œuvre dans la même étude de cas, de sorte que les résultats puissent être comparés à ceux des sections précédentes. Il est démontré que le concept de "package" peut également soutenir les décisions prises dans la phase de conception du système de chauffage, en particulier dans la sélection des composants appropriés en fonction de l'estimation de la performance du système. En outre, le chapitre 6, composé essentiellement d'un article publié dans un journal scientifique, analyse le lien entre les politiques publiques européennes relatives aux produits du bâtiment et celles liées à la performance énergétique des bâtiments: il est conclu qu'elles pourraient être mieux alignées. / Environmental performances of products largely influence performances of systems. Moreover, systems have still an untapped energy-saving potential concerning environmental performances at system level rather than at the level of the individual products of which they are composed.The objective of this work is to propose an approach to deal with energy performance assessments at system level considering information/data from European product policies (Ecodesign, Energy Labels, Green Public Procurement and EU Ecolabel). The hypothesis here is that environmental product policies, that have been very useful in facilitating a homogeneous rating scheme in the EU market for individual products, can also be advantageously used in a method to assess the energy performance of systems.This research work proposes a simplified method for supporting the design of good performing heating systems using data from EU product policies, which is available during the design stage. Firstly, a system modelling with a top-down approach is used so that system aspects (geographical conditions, building characteristics, etc.) are regarded. Secondly, the system energy performance is calculated from a bottom-up approach so that, from the performance of the products and sub-systems composing the system. The method has 5 steps divided in two main phases: diagnostic of the initial system and improvement. The method is supported by an original calculation tool which determines the energy parameters (energy demand, energy losses, energy consumption and low-emission energy efficiency) at system level using performance figures from EU product policies. It helps assessing how good a heating system is by setting worst, benchmark and best possible systems. The method is flexible, and allows different product configurations to be assessed and can hence support the design activities of heating systems.The method is tested on a real case study, the re-design of existing heating systems of a dwelling in north Italy, including a solar hot water system and a space heating system. The case study demonstrates the potential of improvement of the heating systems based on the results produced by the method, by helping selecting products currently available in the market. In addition, based on the assessment, several improved design alternatives can be proposed combining different performances of the products which compose the heating systems.The dissertation also analyses the evolution of the different approaches of EU product policies (product, extended product and system). In particular, the package concept set in the energy labelling regulations of heating systems is studied in detail. The package label of Regulation 811/2013 is implemented on the same prior case study so that results can be compared with the ones of previous sections. It is shown that the package concept can also support decisions made in the building design phase especially in the choice of appropriate components based on estimation of system performances. In addition, the peer-reviewed paper analyses the link of building-related product policies with the Energy Performance of Buildings Directive, and it is concluded that they should be somehow better aligned.
22

Otimização de parâmetros de projeto de tubulações de sistemas de calefação por piso radiante. / Optimization of piping design parameters for a radiant floor heating system.

María Carolina Díaz Rastello 02 September 2013 (has links)
Devido à climatização dos ambientes internos condicionar o bem estar e o conforto térmico das pessoas é que se fazem necessárias novas pesquisas que procurem potencializar as tecnologias existentes e reduzir tanto os custos de instalação quanto o consumo de energia. É sabido que os sistemas convencionais de calefação proporcionam um alto consumo de energia e uma emissão de níveis de ruído muitas vezes inaceitáveis, entretanto os sistemas radiantes ganham, a cada dia, uma maior abrangência como alternativa de climatização devido às suas vantagens comparativas com relação aos sistemas convencionais. O emprego de sistemas de calefação por piso radiante em muitos países é limitada pelo preço da instalação como consequência do elevado custo dos materiais como é o caso da fabricação das tubulações. Estas geralmente são fabricadas de polietileno ou de cobre, sendo este ultimo o que entrega um maior desempenho térmico e, por conseguinte um melhor fornecimento de energia, mas o elevado custo deste material restringe o seu uso principalmente ao setor residencial, podendo atingir um mercado maior que compreenda edifícios públicos, de escritório, escolas, hospitais, etc. Com isso, este trabalho procura reduzir a quantidade de materiais de tubulação necessários para garantir o desempenho do sistema e o conforto térmico de uma habitação aquecida com um sistema radiante. Para isto, foi desenvolvida a resolução numérica do modelo matemático da transferência de calor no interior do piso pelo método dos volumes finitos na formulação implícita e implementada em código computacional na linguagem Matlab. Para isto, foram considerados dois parâmetros fundamentais para garantir o conforto térmico da habitação que correspondem à temperatura da água e a distancia entre os tubos que compõem o sistema. A análise corresponde ao cálculo da temperatura superficial do piso para distintas temperaturas da água e distintas distâncias, obtendo resultados interessantes que permitem reduzir o custo da instalação em até um 40%. / Due to temperature control of interiors conditioning the well-being and the thermal comfort of people, it is necessary to make new researches aiming to improve the existing technologies and to reduce both installation costs and energy consumption. It is known that the use of traditional heating systems involves high energy consumption and, in some cases, unacceptable noise levels; while radiant systems are gaining a wider scope as a heating alternative due to its advantages compared to conventional systems. The use of radiant floor heating systems in Brazil is limited by installation cost due to the high price of required materials. This fact restricts the use of these systems primarily to the residential sector. However, it may be possible for this technology to reach a larger market, including public buildings, offices, schools and hospitals. Therefore, to optimize the most relevant design parameters relating to the thermal performance of the system and reduce both the amount of required materials and the system operating time, this paper elaborates on a method consisting of a high-resolution numerical mathematical model of the heat transfer within a floor using a finite control volume method with an implicit solution scheme. In this work, we consider how the properties of the materials, environmental thermal comfort factors and the performance of the system work together with the theoretical underpinnings of the heat transfer phenomenon to define the design parameters to optimize the materials and provide greater control over the energy consumption. This optimization is achieved without changing any environmental thermal comfort conditions or the well-being of the occupants. Finally, a numerical solution for the heat transfer within the floor is implemented using the computer code Matlab.
23

Desempenho energético e caracterização dos sistemas de aquecimento de água de piscinas. / Energetic performance and characterization of swimming pool heating systems.

Claudio Azer Maluf 16 June 2010 (has links)
O objetivo deste trabalho é investigar o desempenho energético de dois diferentes tipos de sistemas de aquecimento de piscinas: á gás natural e por bomba de calor elétrica. Foi realizada instrumentação em duas piscinas localizadas em uma mesma academia, cada uma delas dotada de um dos tipos de sistema de aquecimento. Além destas duas piscinas, que são objeto de investigação desta pesquisa, outras quatro piscinas, localizadas cada uma em um local distinto na cidade de São Paulo, também receberam instrumentação e a coleta de dados está sendo executada através de sistemas de aquisição de dados, para posterior análise e novos trabalhos de pesquisa. Como resultados da análise das duas piscinas, obteve-se um coeficiente de desempenho - COP, médio para o sistema de aquecimento por bomba de calor igual a 4. Para o sistema a gás natural, os resultados para a eficiência global do sistema indicaram 76%, ao passo que o rendimento apenas dos aquecedores foi de 82%. As análises dos dados permitiram comprovar a influência da temperatura ambiente sobre o COP da bomba de calor. Quanto menor a temperatura do ar, menor o COP. A Temperatura do ar também mostrou forte influência sobre o consumo de energia. / The aim of this research is to investigate the energetic performance of two distinct kinds of swimming pool heating systems: gas-fired and electric heat pump. A practical instrumentation research was prepared in these two indoor swimming pools, placed in the same location. Besides these, other four swimming pool, placed each in a different ambient in the city of São Paulo also received the instrumentation so that it will be possible to run future researches, once the data is already being collected by the data loggers installed. As a result of the data analysis, it was found that the average coefficient of performance of the heat pumps studied is 4. For the natural gas fired system, the global efficiency factor was found to be 76%. The efficiency of the heaters isolated was found to be 82%. This research showed that the COP of heat pump systems has strong correlation with the air temperature. The lower the air temperature, the lower the COP. Temperature also has strong influence on the consumption of energy.
24

Inverkan av värmesystem på termisk komfort i ett flerbostadshus med hänsyn till energianvändning / Impact of heating systems on thermal comfort in a residential building with regard to energy use

Larek, Adrian, Tran, Jimmy January 2015 (has links)
Inomhusklimatet har en avgörande roll för människans hälsa och välmående då människor befinner sig inomhus i nästan halva sitt liv. Det finns flera aspekter till hur det ska erhållas ett bra inomhusklimat men de mer betydelsefulla aspekterna är både god luftkvalitet och termisk komfort. Samtidigt som innebörden av reducering av energianvändning har en viktig roll i dagens utveckling. Då det ständigt arbetas med att försöka reducera energianvändningen i syfte till att underlätta för miljö- belastningen, väcker det frågor om hur den termiska komforten påverkas av detta. Rapportens syfte kommer därmed ligga i identifikation av uppvärmningssystem för ett givet flerbostadshus i Stockholmsområdet med fokus på termisk komfort och energianvändning. Utvärderingen baseras på olika typer av inverkan från diverse system som har utförts med beräkningssprogrammet IDA ICE. Ett referensfall för ett flerbostadshus användes som underlag och modellerades enligt A- och K-ritningar samt indata enligt Sveby. Det kommer även att inkludera de miljöcertifieringar som används i störst utsträckning här i Sverige och både ange deras krav gällande den termiska komforten samt respektive fokusområde då olika miljöcertifieringar har olika bedömningskriterier.   Under denna studie visade det sig att det sällan tas hänsyn till den termiska komforten på motsvarande sätt som energianvändningen. Det har även visat sig att i de fall där krav gällande den termiska komforten finns, är den otillräckligt definierad för att ge en god uppfattning av komforten. Kraven tar, med andra ord, inte hänsyn till hur bra ett hus presterar under ett helt år utan fokuserar på ett momentant värde. Till simuleringen gjordes en känslighetsanalys som påvisade vikten och behovet av en tydlig standard för odefinierade variabler för att uttrycka människors bedömning av termisk komfort. Efter samtliga simuleringarna, granskades energiberäkningar efter erhållen granskningsmall från WSP Systems i syfte att utföra en egenkontroll samt ge ett underlag för rimlighetsbedömning. Från de erhållna resultaten visade det sig att golvvärme och ökad börvärde till 22 °C gav en ökad termisk komfort men samtidigt en ökning i energianvändningen medan FTX-systemet med radiatorer gav upphov till reducerad energianvändning med cirka en tredjedel samt en liten ökning av den termiska komforten. Det visade sig även vara att vid val av FTX-systemet gav högst årlig energibesparing men att det även bör tas hänsyn till installationskostnaderna för FTX-system och golvvärmesystemet till skillnad från om börvärdet ökas till 22 °C. Det blir då en kostnadsfråga och en avgörande parameter för val bland dessa tre systemen. / The indoor climate plays a crucial role in human health and well-being when people are indoors for nearly half their life. There are several aspects to how one should achieve good indoor climate, but the more significant aspects are both good air quality and thermal comfort. Simultaneously one must regard that the reduction of energy has an important role in today’s development. While trying to reduce energy consumption in order to facilitate the environmental load, it raises the questions whether the thermal comfort is affected by this.  The purpose of the report will lie in the identification of a heating system for a given apartment building in the Stockholm area, with a focus on thermal comfort and energy use. The evaluation is based on various types of impacts from various systems that have been computed in IDA ICE. A reference case for an apartment building was used as a basis and was modeled according to architectural and constructional drawings while input data was used according to Sveby. It will also include the environmental certifications used in Sweden and specify their requirements regarding the thermal comfort, and each focus area as various environmental certifications have different assessment criteria’s. During this study it was found that we rarely take into account the thermal comfort in the same way we do with the energy consumption. It has also been found that in cases where the requirements for the thermal comfort exist, it is often insufficiently defined to provide one with a good perception of comfort. The requirements do, in other words, not take into account how well a building performs during a whole year but instead focuses on one instantaneous value. For the simulation a sensitivity analysis was made that revealed the importance and necessity of a clear standard for undefined variables to express the people’s assessment of thermal comfort. After the simulation part, the energy calculations were examined according to a review template from WSP Systems. This provided a basis for fair consideration. From the obtained results it was shown that floor heating and increasing the setpoint to 22 °C gave an increased thermal comfort but at the same time an increase in energy use. An HVAC system with a heat exchanger and radiators resulted in reduced energy use by about a third from the reference case and a slight increase in current thermal comfort. It also proved that the choice of an HVAC system with heat exchanger produced the highest annual energy savings. However one must take into account installation costs for different types of systems as opposed to when the setpoint is increased to 22 °C. Thus it becomes a cost issue and a critical parameter for selecting among these three types of solutions.
25

Solfångare : Ett system för att minska energitillförseln / Solar collectors : A system for reducing energy supply

Wikström, Ludvig January 2020 (has links)
Klimatet och samhället förändras hela tiden och medvetenheten för konsekvenserna ökar. Genom att utnyttja alla tillgängliga delar i en energieffektivisering blir det möjligt att minska den tillförda energin till fastigheten. Detta arbete kommer belysa den potentiella energin i solen som kan utnyttjas för att värma upp fastigheter och andra resurser som har ett värmebehov. Rapporten kommer titta på hur solfångare kan bidra med värmeenergi till Hedlunda förskola. Med hjälp av beräkningar kommer lutningen på solfångarna visa vilka skillnader som framkommer gällande energimängd samt när energin går att nyttja. För att kunna besvara syftet med projektet kommer tre frågeställningar besvaras:  ·       Är det möjligt att minska energibehovet med 2,5 kWh/m2 med hjälp av solfångare? ·       Är det ekonomiskt lönsamt att använda solfångare för att minska energibehovet? ·       Hur löser man ett eventuellt problem med överhettning när energin inte utnyttjas under sommaren? Den metod som har använts för att undersöka solfångarnas tillförda energi är främst via beräkningar i Excel. För att få en ökad förståelse har litteraturstudier och informativa webbplatser använts. Avslutningsvis så visade resultatet att det är fullt möjligt att minska energibehovet årligen med 2,5 kWh/m2 eller 4 625 kWh totalt med solfångare.  Det framkommer att det inte är ekonomiskt lönsamt att använda sig av solfångare i den undersökta fastigheten. Detta beror till stor del på att den nuvarande uppvärmningen uppnås med relativt billig fjärrvärme. Att fjärrvärmen dessutom är billigast under sommaren då solfångarna är mest produktiva försvårar lönsamheten ytterligare. Det finns ett antal tekniska lösningar som gör det möjligt att undvika överhettning och kokning i systemet vilket möjliggör för en installation av solfångare. Sammanfattningsvis är det möjligt att använda sig av solfångare för att komma ner till energinivåer för ett internationellt certifierat passivhus. Solfångare kan vara intressant för Umeå Kommun trots att det inte är ekonomiskt lönsamt. En installation av solfångare kan ge Umeå Kommun mer kunskap om hur solfångare fungerar i praktiken samt vara ett budskap att man satsar på innovativitet och framtiden. / The climate and society are constantly changing, and awareness of the consequences of both is increasing. By utilizing energy efficient solutions, it will be possible to reduce the energy supplied to the system. This work will highlight the potential energy in the sunlight that can be used to heat structures and other facilities that have a heating demand. The report will look at how solar collectors can contribute thermal energy to Hedlunda preschool. By means of various calculations, the tilt angle of the solar collectors will show what differences appear in the current amount of energy and when the energy can be used. To fulfill the purpose of the project, three questions will be answered: ·        Is it possible to reduce the energy demand by 2.5 kWh/m2 with the help of solar collectors? ·        Is it economically profitable to use solar collectors to reduce external energy demand? ·        How do you solve a possible problem with overheating when the energy is not used during summer?  The method that has been used to investigate the solar energy supply is primarily calculations in Excel. To gain a better understanding, literature studies and informational websites have been used. In conclusion, the results showed that it is quite possible to reduce the yearly energy demand by 2.5 kWh/m2 living space or 4,625 kWh total with solar collectors. However, using solar panels in the investigated property is not financially profitable. This is largely because the heating is currently managed by a cheap district heating. Furthermore, the fact that district heating is at its cheapest during summer when solar collectors are most productive further complicates profitability. There are several technical solutions that make it possible to avoid overheating and boiling in the system, which allows for the installation of solar panels. In summary, it is possible to use solar collectors to reduce energy levels to an international certified passive house standard. Solar collectors can be interesting for Umeå Kommun even though it is not financially profitable. An installation of solar collectors can give Umeå Kommun more knowledge about how solar collectors work in practice and be a message that they are investing in innovation and the future.
26

Numerical study of performance of porous fin heat sink of functionally graded material for improved thermal management of consumer electronics

Oguntala, George A., Sobamowo, G., Abd-Alhameed, Raed, Noras, James M. 27 March 2019 (has links)
Yes / The ever-increasing demand for high performance electronic and computer systems has unequivocally called for increased microprocessor performance. However, increasing microprocessor performance requires increasing the power and on-chip power density of the microprocessor, both of which are associated with increased heat dissipation. In recent times, thermal management of electronic systems has gained intense research attention due to increased miniaturization trend in the electronics industry. In the paper, we present a numerical study on the performance of a convective-radiative porous heat sink with functionally graded material for improved cooling of various consumer electronics. For the theoretical investigation, the thermal property of the functionally graded material is assumed as a linear and power-law function. We solved the developed thermal models using the Chebyshev spectral collocation method. The effects of inhomogeneity index of FGM, convective and radiative parameters on the thermal behaviour of the porous heat sink are investigated. The present study shows that increase in the inhomogeneity index of FGM, convective and radiative parameter improves the thermal efficiency of the porous fin heat sink. Moreover, for all values of Nc and Rd, the temperature gradient along the fin of FGM is negligible compared to HM fin in both linear and power-law functions. For comparison, the thermal predictions made in the present study using Chebyshev spectral collocation method agrees excellently with the established results of Runge-Kutta with shooting and homotopy analytical method. / Supported in part from PhD sponsorship of the first author by the Tertiary Education Trust Fund of the Federal Government of Nigeria.
27

A Hammerstein-bilinear approach with application to heating ventilation and air conditioning systems

Zajic, I. January 2013 (has links)
This thesis considers the development of a Hammerstein-bilinear approach to non-linear systems modelling, analysis and control systems design, which builds on and extends the applicability of an existing bilinear approach. The underlying idea of the Hammerstein-bilinear approach is to use the Hammerstein-bilinear system models to capture various physical phenomena of interest and subsequently use these for model based control system designs with the premise being that of achieving enhanced control performance. The advantage of the Hammerstein-bilinear approach is that the well-structured system models allow techniques that have been originally developed for linear systems to be extended and applied, while retaining moderate complexity of the corresponding system identification schemes and nonlinear model based control designs. In recognition of the need to be able to identify the Hammerstein-bilinear models a unified suite of algorithms, being the extensions to the simplified refined instrumental variable method for parameter estimation of linear transfer function models is proposed. These algorithms are able to operate in both the continuous-time and discrete-time domains to reflect the requirements of the intended purposes of the identified models with the emphasis being placed on straightforward applicability of the developed algorithms and recognising the need to be able to operate under realistic practical system identification scenarios. Moreover, the proposed algorithms are also applicable to parameter estimation of Hammerstein and bilinear models, which are special cases of the wider Hammerstein-bilinear model class. The Hammerstein-bilinear approach has been applied to an industrial heating, ventilation and air conditioning (HVAC) system, which has also been the underlying application addressed in this thesis. A unique set of dynamic control design purpose oriented air temperature and humidity Hammerstein-bilinear models of an environmentally controlled clear room manufacturing zone has been identified. The greater insights afforded by the knowledge of the system nonlinearities then allow for enhanced control tuning of the associated commercial HVAC control system leading to an improved overall control performance.
28

Identificação de barreiras para a ampliação do uso de gases combustíveis para aquecimento de água no setor residencial / Identification of barriers to increase the use of domestic gas based water-heating systems

Barufi, Clara Bonomi 29 August 2008 (has links)
Este trabalho é motivado pela constatação de que a instalação de sistemas de aquecimento de água a gases combustíveis nos apartamentos novos pode ter custos inferiores à instalação de sistemas elétricos e pelas perspectivas de aumento da oferta de gás natural no país. Considerando isso e a perspectiva de aumento no consumo de eletricidade, a pesquisa procura identificar barreiras para expansão do uso dos sistemas a gás, sugerindo formas para que sejam superadas. Considerando que as decisões tomadas durante a construção definem em grande medida os usos da energia nos imóveis, o trabalho se baseia numa pesquisa de campo desenvolvida por meio de entrevistas com agentes da construção civil. Inclui ainda uma contextualização sobre o uso da energia no setor residencial. Essa contextualização mostra a evolução do mercado brasileiro de gases combustíveis, a baixa participação histórica desses energéticos no aquecimento de água e as perspectivas de crescimento da oferta de gás natural no país. Também descreve o uso de água quente para banho, abordando os principais sistemas de aquecimento disponíveis no mercado paulistano. Perspectivas relativas ao aumento do consumo de eletricidade e de desenvolvimento do mercado imobiliário completam essa contextualização. A pesquisa mostra que já há ampla disseminação do uso de sistemas de aquecimento de água a gás na cidade de São Paulo. Esse desenvolvimento deveu-se a fatores como a obrigatoriedade da introdução de tais sistemas em alguns tipos de construção a partir de meados dos anos 1980, as exigências de conforto dos consumidores de classe média e classe alta e ao racionamento de eletricidade de 2001. Por outro lado, verifica-se que o chuveiro elétrico continua sendo usado nas construções voltadas para a classe baixa. Como esse é o segmento com maior demanda por novas residências, identifica-se um espaço importante para substituição de eletrotermia e aumento do uso dos gases combustíveis para aquecimento de água. / This research is motivated by the verification that the installation of gas based water-heating systems in new apartments may be cheaper than the use of electric systems. It is also motivated by the perspectives of a growing supply of natural gas in the country. Considering these points and the perspective of general growing use of electricity, this research identifies barriers to expand the use of gas based systems, suggesting ways to overcome those barriers. Considering that the energy uses in an apartment are largely affected by decisions taken during the construction of the building, the study is based on a field research developed through interviews with construction agents. It also includes a definition on the residential energy use, which details the gas (natural gas and LPG) market evolution, the historically reduced use of these fuels in water-heating systems, and the perspectives of rising supply of natural gas in Brazil. It also describes the use of hot water to hygiene, considering the main systems available in São Paulo. This context is completed by the perspectives related to the increase of electricity demand and the current real estate market development. The research concludes that gas based water-heating systems are already extensively used in São Paulo. This development is related to the mandatory use of those systems in some apartment configurations, the users demand for comfort, and the 2001 electric power shortage. On the other hand, it shows that electric showers are still largely used in building of poorer families. Since this segment has the largest demand for new houses in the country, there is space to substitute energy consumed for thermal purposes with the direct use of gas.
29

Identificação de barreiras para a ampliação do uso de gases combustíveis para aquecimento de água no setor residencial / Identification of barriers to increase the use of domestic gas based water-heating systems

Clara Bonomi Barufi 29 August 2008 (has links)
Este trabalho é motivado pela constatação de que a instalação de sistemas de aquecimento de água a gases combustíveis nos apartamentos novos pode ter custos inferiores à instalação de sistemas elétricos e pelas perspectivas de aumento da oferta de gás natural no país. Considerando isso e a perspectiva de aumento no consumo de eletricidade, a pesquisa procura identificar barreiras para expansão do uso dos sistemas a gás, sugerindo formas para que sejam superadas. Considerando que as decisões tomadas durante a construção definem em grande medida os usos da energia nos imóveis, o trabalho se baseia numa pesquisa de campo desenvolvida por meio de entrevistas com agentes da construção civil. Inclui ainda uma contextualização sobre o uso da energia no setor residencial. Essa contextualização mostra a evolução do mercado brasileiro de gases combustíveis, a baixa participação histórica desses energéticos no aquecimento de água e as perspectivas de crescimento da oferta de gás natural no país. Também descreve o uso de água quente para banho, abordando os principais sistemas de aquecimento disponíveis no mercado paulistano. Perspectivas relativas ao aumento do consumo de eletricidade e de desenvolvimento do mercado imobiliário completam essa contextualização. A pesquisa mostra que já há ampla disseminação do uso de sistemas de aquecimento de água a gás na cidade de São Paulo. Esse desenvolvimento deveu-se a fatores como a obrigatoriedade da introdução de tais sistemas em alguns tipos de construção a partir de meados dos anos 1980, as exigências de conforto dos consumidores de classe média e classe alta e ao racionamento de eletricidade de 2001. Por outro lado, verifica-se que o chuveiro elétrico continua sendo usado nas construções voltadas para a classe baixa. Como esse é o segmento com maior demanda por novas residências, identifica-se um espaço importante para substituição de eletrotermia e aumento do uso dos gases combustíveis para aquecimento de água. / This research is motivated by the verification that the installation of gas based water-heating systems in new apartments may be cheaper than the use of electric systems. It is also motivated by the perspectives of a growing supply of natural gas in the country. Considering these points and the perspective of general growing use of electricity, this research identifies barriers to expand the use of gas based systems, suggesting ways to overcome those barriers. Considering that the energy uses in an apartment are largely affected by decisions taken during the construction of the building, the study is based on a field research developed through interviews with construction agents. It also includes a definition on the residential energy use, which details the gas (natural gas and LPG) market evolution, the historically reduced use of these fuels in water-heating systems, and the perspectives of rising supply of natural gas in Brazil. It also describes the use of hot water to hygiene, considering the main systems available in São Paulo. This context is completed by the perspectives related to the increase of electricity demand and the current real estate market development. The research concludes that gas based water-heating systems are already extensively used in São Paulo. This development is related to the mandatory use of those systems in some apartment configurations, the users demand for comfort, and the 2001 electric power shortage. On the other hand, it shows that electric showers are still largely used in building of poorer families. Since this segment has the largest demand for new houses in the country, there is space to substitute energy consumed for thermal purposes with the direct use of gas.
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Didelių erdvių, turinčių didelius įstiklintus paviršius, mikroklimato užtikrinimo galimybės / The Possibilities to Ensure Microclimate in Large Areas with Large Glazed Surfaces

Bartkus, Edvinas 04 February 2013 (has links)
Darbo tikslas – naudojant kompiuterinį modeliavimą ištirti, kaip formuojasi temperatūriniai laukai didelėse erdvėse šalia šaltų įstiklintų paviršių, ir nustatyti, koks šildymo būdas labiausiai tinka mikroklimato parametrų užtikrinimui tokiose patalpose. Pasirinkus kompiuterinį programinį paketą SolidWorks ® Flow Simulation skirtingų aukščių patalpose sumodeliuotas ir išnagrinėtas temperatūrų pasiskirstymas prie įvairių įstiklintų paviršių, esant skirtingoms šildymo sistemoms. Darbe išanalizuoti 14 variantų patalpų, turinčių skirtingą įstiklinimo plotą, modeliai. Jose sumodeliuotos radiatorinio, grindinio ir orinio šildymo sistemos. Darbą sudaro įvadas ir problemos analizė, tikslo ir uždavinių jam pasiekti parinkimas, literatūros šaltinių apžvalga, tiriamų objektų analizė, modeliavimo programinų paketų apžvalga ir tinkamiausio programinio paketo pasirinkimas, modeliavimo rezultatų aptarimas ir išvados, informacijos šaltiniai, priedai. Nustatyta, kad geriausias šildymo būdas patalpoms su dideliais įstiklintais paviršiais yra radiatorinis. Darbo apimtis – 81 psl. teksto be priedų, 65 iliustr., 5 lent., 49 bibliografiniai šaltiniai, 2 priedai. / The assignment of this project is to investigate the forming of various temperature fields in large volumes next to cool glazed surfaces using digital modelling and determine the most efficient heating system solution for ensuring microclimate parameters in such accommodations. The heat distribution in various height spaces next to changing size glazed surfaces is modelled and analysed using SolidWorks ® Flow Simulation software package, comparing the results of several different heating systems. In this paper are analyzed 14 models of accommodations with changing size glazed surfaces, every with one or more of three: radiator, floor and air heating system. This paper consists of introduction, problem analysis, main objective and tasks to achieve it selection, source literature review, investigated objects analysis, modelling software packages review and a choice of the most suitable, simulations results interpretation and conclusion, references and appendixes. It was determined that most suitable heating system for indoor spaces with large glazed surfaces is radiator one. This paper consists of 81 pages of text, 65 pictures, 5 tables, 49 references, 2 appendixes.

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