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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

Etudes des couplages thermohydrauliques en régime variable d'un système thermique avec stockage : application à la production d'eau chaude sanitaire à partir de la valorisation d'une source de chaleur basse température / Study of thermal-hydraulic couplings of a thermal storage system under variable conditions : application to the domestic hot water supply system with the recovery of a low temperature heat source

Segond, Guillaume 05 June 2015 (has links)
Le travail présenté ici a pour objectifs d’étudier et d’optimiser les performances énergétiques d’un chauffe-eau thermodynamique couplé à un stockage par chaleur sensible. La ressource utilisée consiste en la récupération de chaleur sur l’air extrait d’un logement de type collectif. L’enjeu est de caractériser les conditions dans lesquelles le système est capable d’assurer les besoins avec des performances requises lorsque les conditions aux limites sont très fluctuantes. Sur le plan fonctionnel, le système doit être le plus simple possible du point de vue de sa configuration hydraulique et de sa stratégie de régulation.Pour cette étude, nous avons développé un modèle physico-corrélatif sur TRNSYS pour simuler et analyser les différents scenarios et les couplages thermohydrauliques entre les composants du système. En parallèle de cette démarche de modélisation, nous avons conçu et mis en œuvre un dispositif expérimental à l’échelle 1 à des fins de validation du modèle sur une large plage de conditions opératoires.L’analyse des résultats, notamment sur la nature des écoulements au sein du ballon de stockage, a mis en évidence l’influence majeure d’un certain nombre de paramètres sur les performances du système. En particulier, la robustesse des performances face à des fluctuations importantes des conditions aux limites peut être assurée grâce à une stratégie de régulation adaptée.Cette étude a finalement conduit à proposer un modèle réduit pour le dimensionnement du système qui prend en compte les paramètres le plus pertinents pour la stratégie de régulation. / The work presented here aims to study and optimize the energy efficiency of a heat pump water heater coupled with a sensible heat storage. The resource used consists of heat recovery from exhaust air of a collective type of housing. The challenge is to characterize the conditions in which the system is capable of ensuring the needs with performance required when the boundary conditions are very volatile. Functionally, the system should be as simple as possible from the viewpoint of its hydraulic configuration and its control strategy.For this study, we developed a TRNSYS numerical model to simulate and analyze different scenarios and thermal hydraulic couplings between the system components. In parallel with this modeling approach, we designed and implemented an experimental set up with realistic scale to validate the model over a wide range of operating conditions.The analysis of the results, including the nature of flows within the storage tank, highlighted the major influence on a number of parameters on the system performance. In particular, the robust performance in the face of significant fluctuations of the boundary conditions can be ensured through appropriate control strategy.This study eventually led to propose a model for the design of the system that takes into account the most relevant parameters for the control strategy.
22

Rekonstrukce vytápění v rodinném domě / Retrofit of heating system in a family house

Doležel, Pavel January 2020 (has links)
The master’s thesis deals with the solid-fuel fired furnaces, complying with the new emission legislation, and their application in central heating. The introductory part of the thesis focuses on the theory of solid fuels combustion, pertinent legislation, and various designs of solid-fuel fired furnaces. The main part of the thesis deals with the design of a central heating system for a townhouse with a solid-fuel fired furnace as the primary heat source for central heating. A roof-mounted PV system was considered for solar-assisted domestic hot water heating. The energy performance of the house was evaluated with the use of the degree-day method and also with a detailed computer simulation in TRNSYS. As an appendix, the thesis includes the detailed engineering calculations and the engineering drawings and diagrams of the central heating system.
23

Zásobník tepla solární soustavy / Solar hot water storage tank

Vyhlídalová, Karolína January 2020 (has links)
The solar hot water storage tank is off great importance in the solar collector array. It allows transformed energy accumulation thus deals with the inconsistency between supply and demand. The suitable design of the storage tank can improve system efficiency. The storage capacity represents the balance between the amount of stored hot water and the tank's heat losses. The design of the storage capacity is based on three hypotheses. The coverage of hot water demand by solar energy, the ratio between storage capacity and solar thermal collector area and the prediction that the storage capacity corresponds to one- to twofold hot water demand. The purpose of this thesis is to share an understanding of the solar storage tanks design and to improve the design through numerical simulation, experimentations and general calculations. It also focuses on the confirmation of the used hypotheses and determination of the best way to design the solar storage tank for general practice and further potential discussions. The simulation model has three variables – the storage capacity, collector area and the number of occupants. The intent is to find the interdependence of these three variables. The purpose of the simulations is to modify the design of the solar tank based on the mutual influence of studied parameters. The modifications are performed based on the users' needs.
24

Návrh vytápění z pohledu primární energie / Proposal of heating from the perspective of the primary energy

Jurka, Vít January 2014 (has links)
This master´s thesis proposal addresses the heating from the perspective of primary energy in the object. The building is located in Brno and is used as a villa with a pool hall. The object of this work is the selection of appropriate variants of three heat sources (gas boiler, pellet and electric) in terms of primary energy. The project is design of the heating system chosen mode of heat, which is a pellet boiler. The theoretical part is focused on the pellets and their history, classification, properties, production, storage and transport.
25

Characterization of greywater heat exchangers and the potential of implementation for energy savings / Värmeväxlare för spillvatten – karakterisering och energibesparingsmöjligheter

Garcia, Jose Daniel January 2016 (has links)
Buildings account for up to 32% of the total energy use in different countries. Directives from the European Union have pointed out the importance of increasing energy efficiency in buildings. New regulation in countries like Sweden establishes that new buildings should fulfill regulations of Nearly Zero Energy Buildings (NZEB), opening an opportunity for new technologies to achieve these goals. Almost 80-90% of the energy in domestic hot water use is wasted from different applications with almost no use and with a lot of potential energy to be recovered. The present work studied the characteristics of greywater heat exchanger as a solution to recuperate heat from greywater to increase efficiency in buildings. This study explored the fluid mechanics involved in the vertical greywater heat exchangers, analyzing the falling film effect present in drain pipes and the effects of the secondary flow generated in the external helical coil. A heat transfer model from a theoretical approach was proposed and validated. In addition, this study explored the different variables influencing the economic feasibility of the technology and an economic analysis was performed. A theoretical comparison between a greywater heat exchanger application and a reference case without it was evaluated highlighting the importance of all the variables involved in the potential of implementation of the technology. The technology shows big potential in households with high water consumptions, especially with electric boilers.
26

Využití odpadního tepla provozu Špitálka / Utilization of Waste Heat from Heating Plant Spitalka

Hromádka, Martin January 2018 (has links)
This master’s thesis deals with utilization of waste heat from heating plant Spitalka. The aim of the thesis is to explain the general principle of the operation of the heating plants, respectively the heating circuit, then to describe the operation of heating plant Spitalka and to try to identify possible sources of waste heat. Other goals are to make the calculation of waste heat and to make the proposal for its utilization. The final aim of the thesis was to design technological device for utilization of waste heat and to carry out economic evaluation. The master’s thesis describes the principle of functioning of the heating circuit. It explains the issue of combined heat and power production, the principle of functioning of the main technological elements, but also the ecology of operation or distribution of heat through the district heating. Then there is a description of the heating plant Spitalka. The thesis also deals with the water treatment and the description of the technological circuit from the beginning to the distribution to the customer. Next, the waste heat source is identified as water in a closed cooling circuit. The amount of this heat energy is calculated and suggestions for its possible utilization are made. As an application, there are selected two systems, heating and domestic hot water heating. The heating is made by heat pump. Based on the calculations, a heating system using two heat pumps in a bivalent way of connection was designed. In conclusion, the results of the design of the heating system are summarized and an economic evaluation is carried out.
27

Energetické hodnocení systémů TZB / Energy Evaluation of Technical Services Systems

Cap, Petr January 2013 (has links)
This Master’s thesis deals with the energy evaluation of existing buildings sports-recreational company complex in Brušperk. For this purpose provides a comparison of selected fuels as an energy source for the heating in terms of economy and their impact on the environment. In addition, provides an overview of existing legislation for elaboration of an energy audit. To complement shows the calculation of return on investment in solar panels on the roof of one of the objects. Calculation is based on the results of performed experimental measurement. Finally, the thesis presents a comparison of energy performance of buildings simulated in the Bsim software with reality.

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