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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

Byggnadsintegrerade Solceller : Applicering till ett flerbostadshus / Building integrated solar cells : Application to a multi-family dwelling

Lantz, Dennis, Stigeborn, Pontus January 2012 (has links)
Denna rapport presenterar det examensarbete som har gjorts i samarbete med företaget SMÅA AB. Syftet med arbetet är att öka kunskapen, för företaget, om solceller ur en teknisk och ekonomisk synpunkt då man väljer att integrera dessa i byggnadsskalet. Viktiga frågor som har tagits upp innefattar lönsamhet vid användning av solceller, möjligheter att integrera solceller samt hur tekniken ser ut idag och hur den kan utvecklas i framtiden. Dessa kunskaper har sedan applicerats på ett planerat flerbostadshus under resultatet. I lösningsförslaget har solceller blivit integrerade i tak och balkongräcken, där olika typer av solceller används baserad på dess respektive egenskaper som är bäst anpassade för ändamålet. Ämnesområden som berörs är energi, solceller, byggnadsintegrering samt ekonomi. Rapporten är baserad på fakta presenterad av yrkesmän, forskare och säljare som har goda kunskaper inom området. Lönsamheten, som är en central fråga, diskuteras under analys och slutsatser har sedan kunnat dras där man kan se att hur valda lösningar fungerar i dagsläget, om det är lönsamt samt hur det skulle kunna se ut. / This report presents the thesis that has been done in collaboration with SMÅA Corporation. The underlying aim is to increase knowledge, for the company, on photovoltaic cells from a technical and economic analysis when integrated into the building envelope. Important issues raised include profitability with the use of photovoltaic systems, ways to integrate them and also where the technology stands today and how it may evolve in the future. This knowledge has then been applied in a planned multi-family dwelling in the outcome. In the proposed solution, Photovoltaic systems have been integrated on the roof and balcony railings, where different types of solar cells are used based on their respective properties that are best suited for the purpose. Subject areas covered throughout the report include energy, photovoltaics, building integration and economy. The report is based on the facts presented by industry professionals, researchers and salesmen who are knowledgeable in the field. Profitability, which is a central issue, is discussed during the analysis and conclusions have been drawn where one can see whether the chosen solutions work in the current situation, if it is profitable and how it could look like.
2

Roadmapping and Critical Assessment of Emerging Heat Pump Technologies for Residential Applications

Zechao Lu (16798611) 08 August 2023 (has links)
<p>With increasing concerns about the global warming effects of HFC refrigerants, low-GWP refrigerants and non-vapor compression heat pumps are investigated as potential mid- and long-term replacements for current vapor compression heat pump systems that rely on high-GWP refrigerants. To address the need for more environmentally friendly space cooling and heating, and water heating solutions. the U.S. Department of Energy (DOE) Office of Energy Efficiency & Renewable Energy (EERE) is supporting the development of smarter, more efficient, and affordable heat pumping systems operating with low- or near-zero GWP refrigerants through different programs including the Energy, Emissions, and Equity (E3) Initiative. In addition, the Emerging Technologies (ET) Program within the Building Technologies Office (BTO) emphasized the research and development efforts needed to support new technologies that could reduce energy usage in residential and commercial buildings by 50\% over the next decades. In the literature, limited studies were found that systematically investigated different combinations of conventional and emerging space conditioning and water heating technologies while accounting for real building loads, different climate zones, utility structures, and current state-of-the-art equipment. Existing literature primarily focused on thermodynamic performance evaluations at fixed boundary conditions. In addition, separate sensible latent cooling (SSLC) and other novel cooling and dehumidification systems (e.g., membrane-based systems) can significantly reduce the electricity usage for space conditioning. To compare the performance of conventional and emerging technologies several figures-of-merit such as the second law efficiency, are often used. However, limitations exist in previous studies to define the thermodynamic reversible limits and second law efficiency for cooling and dehumidification systems.</p><p>This study developed a comprehensive modeling framework to evaluate both current state-of-the-art vapor compression systems and emerging HVAC\&R technologies in real-world scenarios. The platform will be used to assess potential energy savings, scalability issues, and the effectiveness of combined technologies for different buildings, climate conditions, and utility structures.</p><p>To compare HVAC technologies, a new physics-based definition for the reversible limit and the second law efficiencies for cooling and dehumidification systems with air recirculation has been developed. The new framework is then extended to define a novel performance metric, the seasonal second law efficiency, to form a universal benchmark for assessing various cooling and dehumidification systems. Five cooling and dehumidification systems including magnetocaloric cooling, solid desiccant dehumidification, and membrane dehumidification are evaluated using this benchmark. Steady-state thermodynamic models are constructed for each system. Second law efficiency for each system under various outdoor temperatures and indoor sensible heat ratios (SHR) are calculated. The annual electricity usage of the five systems is used to justify the seasonal second law efficiency definition. The results show that compared to conventional vapor compression systems with mechanical dehumidification, the membrane-based AMX-R cycle can reduce annual electricity use by 12.2%-22.2% and increase the seasonal second law efficiency by 36%.</p><p>The advancements of nine not-in-kind (defined as non-vapor compression systems, solid-state, and chemical-based systems) technologies, i.e. magnetocaloric, thermoelectric, elastocaloric, electrocaloric, membrane-based, Vuilleumier, sorption, chemical looping, and desiccant, were reviewed in detail and compared with the state-of-the-art vapor compression systems. Suitable figures-of-merit were defined to compare the different technologies from a thermodynamic standpoint as well as technology readiness level. As a result of the thorough literature review, a roadmap was created to track the development of emerging HVAC&R technologies and future developments. More importantly, the roadmap enabled the identification of several case studies to evaluate potential energy savings both for space conditioning and water heating. Techno-economic studies for eight HVAC configurations for space heating, cooling, and water heating were conducted for a realistic building scenario under various climate conditions. Different combinations of advanced equipment such as heat pump water heater (HPWH), ground-source heat pumps (GSHP), cold-climate heat pumps (CCHP), and membrane-heat pumps were compared with traditional vapor compression heat pumps and gas furnaces. A building model was developed in EnergyPlus and validated with historical data from the DC Nanogrid House at the Purdue University campus. A total of eleven climate zones were considered, and both local weather conditions and utility pricing were implemented in the simulations. Moreover, future SEER2/HSPF2 equipment ratings and E3 Initiative targets were also included in the analyses.</p><p>The initial simulation results provided climate-based equipment selection guidelines and quantitative techno-economic assessments. For instance, CCHPs with two-stage compression in heating mode save 10%-20% in annual heating cost compared with single-stage VCHPs in Climate Zone 4A, 4C, 5A, 5B, 6A, and 6B. Membrane evaporative air-conditioners could provide cooling cost savings in places where is a significant cooling load, such as Zone 1A, 2A, 2B, 3A, 3C, 4A, 5A, and 6A. Gas furnaces should only be used in cold places where the electricity price per kWh to gas price ratio is higher than 3. GSHP has the lowest HVAC annual energy cost in six out of eleven climate zones in the U.S. Dual fuel heat pumps are not always the most economical option but yield better average cost savings among the eleven locations. HPWHs should be recommended in areas where the electricity price to gas price ratio is below 3. </p><p>The developed simulation framework will be instrumental to continue in-depth investigations of current and next-generation heat pump technologies. The ultimate goal of this research is to provide future guidelines on the selection of building-specific and climate-specific equipment solutions that will enable energy savings and future decarbonization strategies (e.g., geospatially-resolved simulations).</p>
3

Études expérimentales et numériques d'un micro-cogénérateur solaire : intégration à un bâtiment résidentiel / Experimental and numerical studies of a solar micro-cogenerator : integration into a residential buidling

Martinez, Simon 06 December 2018 (has links)
Ces travaux consistent en l’étude expérimentale et numérique des performances énergétiques d’un prototype de micro-cogénération solaire. L’installation, située sur le campus de l’Université de la Rochelle, fonctionne grâce au couplage d’un champ de capteur solaire cylindro-parabolique de 46,5 m² avec un moteur à vapeur à piston non lubrifié fonctionnant selon le cycle thermodynamique de Hirn. Le système de suivi solaire s’effectue selon deux axes et l’eau est directement évaporée au sein de l’absorbeur des capteurs cylindro-paraboliques. La génération d’électricité est assurée par une génératrice et la récupération des chaleurs fatales doit permettre d’assurer les besoins en chauffage et eau chaude sanitaire d’un bâtiment. La première partie de ces travaux présente les essais réalisés. L’objectif est de réaliser des essais complémentaires pour caractériser le concentrateur solaire, d’étudier les conditions de surchauffe de la vapeur, ainsi que le fonctionnement de l’installation complète en hiver. Ce travail a permis le développement de modèles pour le capteur cylindro-paraboliques, les essais en régime surchauffé ont montré la nécessité d’un appoint pour le fonctionnement d’une telle installation tandis que les essais avec moteur présentent des productions compatibles avec les consommations en électricité et chaleur d’un bâtiment résidentiel. La seconde partie concerne la modélisation des éléments constituant le micro-cogénérateur ainsi que l’intégration de cette installation au bâtiment à l’aide d’un logiciel de simulation thermique dynamique (TRNSYS©). Cette étude propose deux options d’intégration selon le positionnement de l’appoint de chaleur. Pour les deux configurations, des bilans hebdomadaires et annuels sont présentés permettant de discuter les avantages/inconvénients de chaque disposition. Il apparaît que le positionnement de l’appoint sur le circuit primaire permet de piloter la production électrique. L’ajout de l’appoint sur la distribution semble plus facilement réalisable mais empêche le contrôle de la production électrique. / This work consists of the experimental and numerical study of the energy performance of a prototype of solar micro-cogeneration. The facility, located on the campus of the University of La Rochelle, operates by coupling a 46.5 m² parabolic trough solar collector field with an oil-free piston steam engine operating according to the Hirn thermodynamic cycle. The solar tracking system is carried out in two axes and the water is evaporated directly into the absorber of the parabolic trough collectors. Electricity generation is provided by a generator and the recovery of fatal heat must make it possible to meet the heating and domestic hot water needs of a building. The first part of this work presents the tests performed. The objective is to carry out additional tests to characterize the solar concentrator, to study the conditions of steam overheating, as well as the operation of the complete installation in winter. This work has allowed the development of models for the parabolic trough sensor, the tests in overheated mode have shown the need for an extra charge for the operation of such an installation while the tests with motor present productions compatible with the electricity and heat consumption of a residential building. The second part concerns the modelling of the elements constituting the micro-cogenerator as well as the integration of this installation into the building using dynamic thermal simulation software (TRNSYS©). This study proposes two integration options depending on the positioning of the auxiliary heater. For both configurations, weekly and annual reviews are presented to discuss the advantages/disadvantages of each provision. It appears that the positioning of the auxiliary on the primary circuit makes it possible to control the electrical production. The addition of back-up boiler on the distribution seems more easily achievable but prevents the control of power generation.

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