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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

Energioptimering hos Freezing Food AB : Fallstudie i luftväxling och värmeöverföring

Nilsson, Dan, Magnusson Österberg, Patrik January 2017 (has links)
Arbetet handlade om att utreda energibehovet till följd av en industriport mellan ett fryslager och en utlastningsterminal, samt utreda om anläggningens golvvärme kan arbeta med sänkt temperatur för att minska uppvärmingen av fryslagret, båda delarna med syftet att identifiera energiförluster och kunna sänka energiåtgången. Energiförlusten till följd av porten identifierades genom uppmätning av luftflöden för att sedan beräknas över ett år med hjälp av en teoretisk modell. För att undersöka golvvärmens driftsparametrar gjordes en litteraturstudie för att bestämma ifall det vore tillrådligt att sänka dess arbetstemperatur. Slutsatsen blev att portens öppetvarande under år 2016 resulterade i omkring 145MWh i rent termisk energiförlust. Anläggningens vattenburna golvvärme drivs vid cirka 10-12°C vilket är enligt praxis och att en förändring av temperaturen därför inte kan rekommenderas. / This thesis was examining the energy demand due to an industrial gate dividing a freezer warehouse and it’s adjacent loading bay, as well as determining whether the facility’s sub-floor heating could be operated at a lower temperature setting in order to decrease the heat transfer into the freezer, both of which with the purpose to identify energy losses and possibly lower the total energy demand. The energy losses due to the gate were identified by measuring airflow and then calculate the loss over a whole year by means of a theoretical model. To examine the operating parameters of the sub-floor heating, a literature study was conducted in order to determine whether it would be feasible to lower its temperature. The conclusion was that the opening of the gate during year 2016 resulted in about 145MWh of purely thermal energy loss. The facility’s waterborne sub-floor heating is operated at around 10-12°C, which is according to practice, and a change of temperature cannot be recommended.
2

Exergy Analysis Of A Solar Assisted Absorption Heat Pump For Floor Heating System

Sari, Ozgur Gokmen 01 January 2004 (has links) (PDF)
Solar assisted single-stage absorption heat pump (AHP) was used to supply energy to a floor-heating system by using the exergy methods. An existing duplex-house,in Ankara, with a heating load of 25.5 kW was analysed. Heating loads of the spaces in the building were calculated and a floor heating panel was modelled for each space leading to the capacity of the AHP before it was designed. Solar energy was delivered to the evaporator and high temperature heat input delivered to the genarator are met by auxiliary units operating with natural gas.The solar energy gained by flat-plate collectors was circulated through AHP.The anaysis performed according to the storage tank temperature reference value if the water temperature leaving the storage tank exceeds a predetermined value it is directly circulated through the floor heating system. Exergue analysis were carried out with Mathcad program. Exergy analysis showed that irreversibility have an impact on absorption system performance.This study indicated which components in the system need to be improved thermally.A design procedure has been applied to a water-lithium-bromide absorption heat pump cycle and an optimisation procedure that consists of determinig the enthalpy, entropy ,exergy, temperature, mass flow rate in each component and coeficient of performance and exergetic coefficient of performance has been performed and tabulated.
3

Energetická rekonstrukce samostatně stojícího rodinného domu / Energy retrofit of a stand-alone house

Stupka, Jaroslav January 2020 (has links)
The aim of the master’s thesis was to design heating, ventilation and cooling systems and to evaluate possibility of using renewable sources in case of a reconstructed two-storey family house. Air to water heat pump and floor system were designed to ensure both heating and cooling supply in the building. A heat recovery ventilation system was proposed. Gains of electrical energy from photovoltaic array were calculated and then possibility of coverage the heat pump consumption was evaluated. The thesis contains required calculations including building heat losses, heat gains, air exchange rates and the dimensioning of all mentioned systems. Technical drawing is also comprised.
4

Wärmeabgabe teilbeheizter Fußböden

Kremonke, André 16 September 2000 (has links) (PDF)
Mit Hilfe von experimentellen Untersuchungen wird nachgewiesen, daß sich die nutzerseitig abgegebene Wärmestromdichte des außenwandnahen Fußbodenbereiches nicht allein über die Differenz zwischen der Heizflächen- und Raumtemperatur beschreiben läßt. Die Ableitung verallgemeinerbarer Berechnungsansätze ist Schwerpunkt der Arbeit. Die experimentellen Untersuchungen erfolgen in einem Modellraum in Originalgröße. Meßtechnisch erfaßt werden die Oberflächentemperaturen, die Lufttemperaturverteilung, die Luftgeschwindigkeitsverteilung und die örtliche Gesamtwärmestromdichte der beheizten Fußbodenbereiche. Der konvektive Wärmeübergang wird maßgeblich von der über dem Fußboden umgelenkten Falluftströmung an der Außenwand beeinflußt. Zur Berechnung der örtlichen Maximalgeschwindigkeiten wird ein einfacher Berechnungsansatz entwickelt. Mit Hilfe numerischer Untersuchungen erfolgt ein Vergleich verschiedener Heizsysteme hinsichtlich der Empfindungstemperaturverteilung.
5

Návrh vytápění a nuceného větrání pro rodinný dům Doubrava / Heating and ventilation in the "Doubrava" family house

Jirsová, Tereza January 2021 (has links)
The diploma thesis is focused on the design of heating and forced ventilation for the project of the family house Doubrava. In the first two chapters is briefly described the theory and there is also described the project of the family house. The next chapter deals with the design of the forced equal pressure ventilation with the heat and moisture recovery. Than the heat loss are calculated according to the norm ČSN EN 12831-1. The next part is focused on the design of heating system and the heat source for the family house Doubrava. There is described detailed design of the floor heating, including necessary calculations, and also the type of the heat pump, as the heat source and source for hot water heating, is chosen. This part also contains a selection of expansion tank and safety valve and approximate calculation of the size of the primar circuit. The last part deals with the possibilities of using renewable energy sources. At the end of the thesis, there are more detailed results of the calculations and the mechanical drawings of individual designs of the ventilation and heating system and also there are tables of the acquisition costs.
6

A hybrid low - temperature heating system in geothermal retrofitting for public buildings in the Mediterranean climate

Bizimana, Boumediene January 2019 (has links)
More than 50 % of EU’s yearly energy demand is spent on heating and cooling systems with which most of its source is generated from non-renewable fossil fuel [1]. Furthermore, half of the EU buildings are heated with a non-efficient boiler of about 60% or less efficiency [1]. The report released by EU from 1990 to 2007 revealed that fuel combustion and fugitive emission contribute to about 79.3% of total greenhouse gas emissions in CO2 equivalents [1]. The EU-EBPD long-term renovation strategy is to improve the energy performance of all residential and non-residential buildings in its member countries through supporting the renovation of the existing buildings into highly energy efficient and decarbonised buildings [2]. Despite all these EU policies and efforts to replace these non-efficient heating systems, the main challenge is price comparison of different solutions and their efficiency in retrofitting of the heating old systems together with the lack of information about the functioning of those old systems [1]. Thus, the development of an easy to install heating system in retrofitting with low exergy heat supply is a significant contribution to a sustainable solution in minimizing energy resources depletion and environmental emission. Furthermore, efficient system control of these easy to install heating systems, hybrids combinations solution for retrofitting building could be a sustainable solution for the preservation of the existing building. The main objective of this work was to design an easy to install hybrid low-temperature floor heating system in retrofitting buildings and compare its results on energy performance, thermal comfort and indoor air quality with other conventional heating mainly used in the Mediterranean climate. This study was performed in two existing radiators heated buildings located in Sant Cugat del vallès in Catalonia, Spain.The results showed that the hybrid low-temperature heating system has the highest energy performance and energy saving of 48 % and 52% compared to that of existing radiator heating and all air heating, respectively. However, hybrid low-temperature floor heating showed a slow heating response, and consequently, it showed lower operative temperature compared to others even though it was within the recommended standards limits. The hybrid low-temperature heating system with demand-controlled ventilation also showed a better indoor air quality, while as existing radiator with its natural ventilation showed the worst indoor air quality. All three compared heating systems showed a better coefficient of performance with low-temperature heat supply and were able to operate with low-temperature heat supply. / Mer än 50% av EU:s årliga energibehov spenderas på värme- och kylsystem där de flesta av deras källor genereras från icke-förnybart fossilt bränsle [1]. Dessutom värms hälften av EU:s byggnader upp med en ineffektiv panna med cirka 60% eller mindre effektivitet [1]. EU:s rapport från 1990 till 2007 avslöjade att bränsleförbränning och flyktiga utsläpp bidrar till cirka 79% av de totala utsläppen av växthusgaser i koldioxidekvivalenter [1]. EU:s och EBPD:s långsiktiga renoveringsstrategi är att förbättra energiprestanda för alla bostäder och andra byggnader i dess medlemsländer genom att stödja renovering av befintliga byggnader till mycket energieffektiva byggnader [2].Trots alla dessa EU-policyer och ansträngningar för att ersätta dessa ineffektiva värmesystem, är den största utmaningen prisjämförelse av olika lösningar och deras effektivitet i renovering av de gamla värmesystemen tillsammans med bristen på information om hur de gamla systemen fungerar [1]. Därför är utvecklingen av ett installationsenkelt värmesystem med låg värmeförsörjning av exergi ett viktigt bidrag till en hållbar lösning för att minimera energiresurser och miljöutsläpp. Dessutom kan effektiv systemkontroll av dessa värmesystem med olika kombinationslösningar för renovering av byggnaden vara en hållbar lösning för att bevara den befintliga byggnaden.Huvudsyftet med detta arbete var att utforma ett lågtemperaturgolvvärmesystem att använda vid renovering av byggnader och jämföra dess resultat på energiprestanda, termisk komfort och inomhusluftkvalitet med annan konventionell uppvärmning som huvudsakligen används i medelhavsklimat. Denna studie utfördes i två befintliga radiatoruppvärmda byggnadet i Sant Cugat del vallès i Katalonien, Spanien. Resultaten visade att hybridsystemet med låg temperatur har den högsta energiprestandan och energibesparingen på 48% och 52% för den befintliga radiatorvärme respektive luftvärme. Emellertid visade lågtemperaturgolvvärme ett långsamt uppvärmningssvar, och följaktligen visade det lägre driftstemperatur jämfört med de andra systemen trots att det låg inom de rekommenderade standardgränserna. Lågtemperaturvärmesystem med efterfrågningsstyrd ventilation visade också en bättre inomhusluftkvalitet, medan befintliga radiatorer med sin naturliga ventilation visade den sämsta inomhusluftkvaliteten. Alla tre jämförda värmesystemen visade bättre prestanda med lågtemperaturvärmeförsörjning och kunde fungera med lågtemperaturvärmeförsörjning.
7

Estudos de sistemas de aquecimento aplicado a galpões avícolas com uso de elementos finitos

Leva, Flavia Fernandes de 23 November 2010 (has links)
The aim of this research was to evaluate and compare the behavior of temperature inside poultry sheds with bell jar type gas conventional heating and heating in the floor with use of a heat exchanger. It was used the public domain program FEMM 4.2 for the analysis of temperature through the use of finite elements techniques with data collected from two lots. Heating in the floor is made with the hot water flowing through a heat exchanger, which is installed below the bed; this hot water is from solar heaters. From the results obtained with the simulations can be observed that the heating through the floor provides a more homogeneous distribution breast when compared with the bell jar type heating. The flow of heat is upwards supplying thus the most needed heating of the bird that is the pectoral part. Energy consumption evaluation was made with use of LPG; this has enabled a comparative analysis of the quantity of electric energy necessary to provide the same thermal energy and the financial expenses obtained with the heating though LPG or electric energy for each lot. / Essa pesquisa foi conduzida com o objetivo de avaliar e comparar o comportamento da temperatura dentro do galpão avícola com aquecimento convencional tipo campânula a gás com o aquecimento pelo piso com o uso de serpentina. Foi utilizado para a análise do comportamento da temperatura o programa de computador de domínio público FEMM 4.2 que utiliza técnicas de elementos finitos, com base em 2 dos lotes coletados. O aquecimento pelo piso se dá com a utilização de água quente passando por um sistema tipo serpentina, que é instalada abaixo da cama, essa água quente é proveniente de aquecedor solar. A partir dos resultados obtidos com as simulações nota-se que o aquecimento através do piso fornece uma distribuição mais homogênea da temperatura quando comparado com o aquecimento tipo campânula. O fluxo de calor se dá de baixo para cima suprindo assim a necessidade maior de aquecimento da ave que é na parte peitoral. Foi realizada uma avaliação do consumo energético com a utilização do GLP, o que possibilitou uma análise comparativa da quantidade de energia elétrica necessária para fornecer a mesma energia térmica e os gastos financeiros obtidos com o aquecimento via GLP ou energia elétrica para cada lote. / Doutor em Ciências
8

Wärmeabgabe teilbeheizter Fußböden

Kremonke, André 13 June 2000 (has links)
Mit Hilfe von experimentellen Untersuchungen wird nachgewiesen, daß sich die nutzerseitig abgegebene Wärmestromdichte des außenwandnahen Fußbodenbereiches nicht allein über die Differenz zwischen der Heizflächen- und Raumtemperatur beschreiben läßt. Die Ableitung verallgemeinerbarer Berechnungsansätze ist Schwerpunkt der Arbeit. Die experimentellen Untersuchungen erfolgen in einem Modellraum in Originalgröße. Meßtechnisch erfaßt werden die Oberflächentemperaturen, die Lufttemperaturverteilung, die Luftgeschwindigkeitsverteilung und die örtliche Gesamtwärmestromdichte der beheizten Fußbodenbereiche. Der konvektive Wärmeübergang wird maßgeblich von der über dem Fußboden umgelenkten Falluftströmung an der Außenwand beeinflußt. Zur Berechnung der örtlichen Maximalgeschwindigkeiten wird ein einfacher Berechnungsansatz entwickelt. Mit Hilfe numerischer Untersuchungen erfolgt ein Vergleich verschiedener Heizsysteme hinsichtlich der Empfindungstemperaturverteilung.
9

Návrh vytápění polyfunkčního objektu / Space heating of a mixed-use building

Dvořák, Jakub January 2017 (has links)
The subject of this diploma thesis is to design space heating system for building with five floors, where the first above ground floor is used as commercial space. Designed building have one underground floor and four above ground floors. Diploma thesis is designed as project of Building Service, specifically that of Heating. This diploma thesis contains calculations of the design heat load, design of radiators and others heating surfaces, hydraulic balancing, generation of domestic hot water, design of heat source, calculations of safety devices and pumps design. Part of this diploma thesis is also conceptual design of regulation.
10

Tvorba vnitřního mikroklima v domu s "téměř nulovou spotřebou" energie / Creation of internal microclimate in the house with "nearly zero" energy consuption

Fibich, Marek January 2013 (has links)
Design of heating of the house with almost zero energy consumption. The first part describes the analysis of the building and heating, heat pumps theory and evaluation systems with heat pump.In the second part we find three variants of technical solutions. The third part contains solutions for selected variant and it is heating with heat pump air – water.

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