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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.
31

Zdravotně technické a plynovodní instalace v penzionu / Sanitation installation and gas installation in the guesthouse

Matějková, Lucie January 2017 (has links)
The Diploma thesis contains design of plumbing and gas installations in a pension. The theory solves warming of water, ways of warming, and dimensioning according to ČSN 06 0320. The calculation part solves variants of hot water preparations and installations of sewerage water. The practical part contains a design and a projekt of plumbing and gas installations.
32

Corrosion in the coolant circuit of Pansarterrängbil 203

Danielsson, Olivia, Jonsson, Sonja, Mildenberger, Ida January 2016 (has links)
The military vehicle, Pansarterrängbil 203 (PATGB 203) demonstrates a fault. There are some components in a coolant circuit that fail due to corrosion while others are unaffected. One of the affected components that will be investigated in this report is the water heater. The subject of this technical investigation has been an issue for FMV, Swedish Defence Materiel Administration since a decade. While seeking out the cause of the coolant circuit failing, this investigation aim to analyzing the underlying problems considering material, factors of corrosion and organization. In order to establish the origin of material and appearance of corrosion, experiments were performed. The experiments showed that the original material is an Al-Si alloy. The micrographs indicated varying stratification of the corrosion throughout the unit. The corrosive deposits consisted mainly of oxygen, silicon, aluminum and sodium. Consequently, the protecting passive oxide layer is compromised, which results in a direct connection between the coolant and the underlying material. This direct connection gives rise to the development of corrosion in the material. Clear underlying causes of the corrosion were not found but the most probable suggest on galvanic corrosion accelerated by a stray current. Properly grounding the components decreases the stray current in the system and is essential to avoid corrosion. If grounding the components is not sufficient, additional checks of the coolant with attention to the pH-value and the function of corrosion inhibitors may indicate corrosion at an earlier stage.
33

Vytápění objektu hotelového typu plynovým médiem a alternativním zdrojem / Hotel type building heating gas and alternative media source

Byrtus, Miroslav January 2014 (has links)
Proposal for heating the building of the hotel type. The first part describes the detailed description and analysis of heat sources proposed in the third part, which are gas-fired condensing boilers, fireplaces and stoves. In the second part we find two technical solutions involvement boiler room. The third section contains solutions for selected variants.
34

Vytápění objektu plynovou kotelnou a solárním doohřevem vody / Building heating gas boiler and solar water heating

Jelínek, Ondřej January 2015 (has links)
Proposal for heating and water warming of rehabilitation centre. The first part of the project analyses given topic, the matter of calculating heat losses and heating elements proposal. It also deals with heat source for heating, fuel for boilers and condensation boilers functioning. The second part covers the technical design of the theme and the third part deals with the solar system.
35

Energetický zdroj se spalovací turbinou / Power plant with gas turbine

Drábek, Ivo January 2012 (has links)
The goal of this master´s thesis is designing power plant with gas turbine of 50 MWe power output for the site. It includes appropriete choose of gas turbine and its simplified termodynamic calculation, designing the thermal diagram and its calculation, for the parameters complying with nominal temperature of outside air, layout design, annual energy and mass flow results, savings of combined heat and power, intended at this application and economic evaluation of investment.
36

Μελέτη ροϊκών φαινομένων για μεγιστοποίηση θερμανταλλαγής σε ολοκληρωμένο ηλιακό σύστημα συλλέκτη-αποθήκης / Flow field study for maximization of heat transfer in Integrated Collector Storage Solar System.

Γκέρτζος, Κωνσταντίνος 31 March 2008 (has links)
Τα ολοκληρωμένα ηλιακά συστήματα συλλέκτη αποθήκης αποτελούνται από μία δεξαμενή αποθήκευσης, της οποίας τμήμα της επιφάνειας της χρησιμοποιείται σαν ηλιακός συλλέκτης. Συνήθως το ρευστό της αποθήκης είναι το νερό χρήσης. Στο υπό εξέταση σύστημα το νερό χρήσης θερμαίνεται έμμεσα, διερχόμενο μέσα από σωληνώσεις εναλλάκτη θερμότητας που τοποθετείται στο εσωτερικό της παραλληλεπίπεδης δεξαμενής. Για την εντατικοποίηση της μετάδοσης θερμότητας προς το νερό χρήσης, δημιουργείται ανάδευση του ρευστού του δοχείου μέσω κυκλοφορητή, ο οποίος τίθεται σε λειτουργία μόνο όταν υπάρχει ζήτηση ζεστού νερού. Προς αποφυγή παραμορφώσεων τοποθετούνται πτερύγια συγκράτησης που ενώνουν τις δύο μεγάλες επιφάνειες της δεξαμενής. Στην παρούσα διδακτορική διατριβή διερευνήθηκαν τα ροϊκά φαινόμενα στο εσωτερικό του ICS που έχει περιγραφεί προηγουμένως, με στόχο τη μεγιστοποίηση της θερμανταλλαγής μεταξύ των δύο κυκλωμάτων νερού. Για την παρατήρηση του ροϊκού πεδίου καθώς και την λήψη μετρήσεων ταχυτήτων κατασκευάστηκε πειραματική συσκευή με διαφανή τοιχώματα από Plexiglas. Ελήφθησαν μετρήσεις ταχυτήτων και διακυμάνσεων με χρήση συστήματος Laser Doppler διπλής ακτίνας. Για την οπτικοποίηση του ροϊκού πεδίου τοποθετήθηκαν σωματίδια πολυστερίνης στο εσωτερικό της συσκευής. Ελήφθησαν ψηφιακές φωτογραφίες και βιντεοσκοπήσεις του ροϊκού πεδίου. Για την υπολογιστική προσομοίωση χρησιμοποιήθηκε το εμπορικό λογισμικό FLUENT. Αναπτύχθηκε υπολογιστικό μοντέλο και επιλύθηκε με όλα τα διαθέσιμα μοντέλα τύρβης. Στη συνέχεια πραγματοποιήθηκε σειρά υπολογιστικών προσομοιώσεων, στις οποίες διερευνήθηκε η βέλτιστη θέση και το μέγεθος των στομίων ανακυκλοφορίας, η βέλτιστη διάταξη των πτερυγίων συγκράτησης και η βέλτιστη θέση του εναλλάκτη. Επιπλέον προσδιορίστηκε υπολογιστικά και πειραματικά ο χρόνος αποκατάστασης του ροϊκού πεδίου. Τέλος, τα αποτελέσματα συγκρίθηκαν και με πειραματικά αποτελέσματα άλλων εργασιών. Τα συμπεράσματα που εξάγονται έχουν ως ακολούθως: Το μοντέλο τύρβης standard k-ω δίνει τα πιο αξιόπιστα αποτελέσματα. Το υπολογιστικό μοντέλο θεωρείται πιστοποιημένο μετά από πειραματική επιβεβαίωση ταχυτήτων και θερμοκρασιών. Το στόμιο ανακυκλοφορίας δεν πρέπει να τοποθετείται κάθετα στις μεγάλες επιφάνειες της δεξαμενής, ενώ η διάμετρος του πρέπει να είναι 1/2" ή και μικρότερη. Ο χρόνος αποκατάστασης του ροϊκού πεδίου είναι περίπου 35 s. Τα πτερύγια συγκράτησης πρέπει να ακολουθούν τις ροικές γραμμές. Ως βέλτιστη θέση του εναλλάκτη θεωρείται όταν τοποθετείται σε επαφή με το τοίχωμα. / Integrated Collector Storage (ICS) solar systems use part of the hot water storage as collector, i.e. half of the storage surface is used as absorber. Usually, the storage medium serves also as the energy transfer medium (service hot water). In the examined ICS, the service water is heated indirectly, passing through a serpentine heat exchanger placed inside the tank. The heat transfer from the stored water to the service water is intensified by the agitation of the stored water. A simple solution is the recirculation of the stored water by a small pump, which is functioning whenever a request for hot water exists. Fins in suitable positions, connect the front and back surface of the ICS, to withstand the deformation due to pressures by the tank water. In the present PhD thesis, the flow phenomena inside the ICS previous mentioned, are investigated. The aim is the maximization of the heat transfer between the two water circuits. An experimental device was constructed by transparent Plexiglas, for flow visualization and velocity measurements. A dual beam Laser Doppler Velocimetry (LDV) system was used to measure velocities. Polystyrene particles were added in the comprised water, for the visualization of the path lines. Photographs and video films were also taken. The commercial code FLUENT is used for the Computational Fluid Dynamics (CFD) simulations. A CFD model is developed and solutions are obtained using all the available turbulence models. Three main factors that influence the performance are optimized: the position and size of the recirculation ports, the arrangement and size of the interconnecting fins and the heat exchanger placement. The settling time, i.e., the time required for the flow field to be fully developed, is computed both numerically and experimentally. The previous analysis leads to the following conclusions: The standard k–ω model is selected as the most appropriate. The model is validated, with good agreement, against experimental measurements of velocities and temperatures. The placement of the inlet recirculation port perpendicular to the main surfaces of the ICS should be avoided, while its diameter should be 1/2" or less. The settling time is computed about 35s. The interconnecting fins, of the two main ICS surfaces should follow the flow filed path lines. The optimal placement of the tube heat exchanger is in contact with the two major surfaces of the storage tank.
37

熱泵熱水系統生命週期評估與淨能源分析之整合研究 / Integrated Studies on Life Cycle Assessment and Net Energy Analysis of the Heat Pump Water Heater System

郭乃頊 Unknown Date (has links)
根據歐盟2009 年發布之再生能源指令,定義熱泵系統所擷取之大氣熱能、水熱能以及地熱能為再生能源之選項,熱泵技術不受日夜與天候影響,且具安全、有低耗能、低排碳的優點,可應用在空調、暖氣、熱水等設備,備受歐美日本等先進國家重視,也是歐美各國政府極力推廣的項目之一。本研究針對台灣地區家戶住宅所使用小型空氣源熱泵熱水機組,透過環境資源及能源效率的角度,來探討熱泵熱水系統對於台灣住宅部門的適用性。 在研究方法上,針對國內熱泵個案廠商進行系統盤查分析,並且估算使用運轉過程中所需之能源投入,以計算熱水系統在製造過程與運轉使用過程中之環境影響。選擇生命週期評估軟體SimaPro 7.3做為評估工具,使用Eco-Indicator 95、EPS 2000兩種衝擊評估模式,來以生命週期評估探討熱泵熱水系統對環境之影響。並輔以淨能源分析法中能源投資報酬率與能源回收期,以及估算熱泵熱水系統生命週期CO2排放量,來衡量熱泵熱水系統之能源效率是否具有其效益。並進一步針對不同的再生能源發電比例與提升熱泵能源效率比例,探討不同方案的敏感度分析。 根據本研究分析結果顯示,熱泵熱水系統不管從Eco-indicator 95或EPS 2000衝擊評估模式下,運轉使用階段對環境衝擊較大,主要的衝擊項目為重金屬汙染,是因為熱泵熱水系統運轉所使用的電力消耗所致。使用熱泵熱水系統對環境衝擊程度遠較電熱水系統來得小,雖在Eco-indicator 95之衝擊評估模式下,瓦斯熱水系統較熱泵熱水系統環境衝擊程度較小,但以EPS 2000衝擊評估模式下,熱泵熱水系統對環境是最為友善的熱水系統。以淨效益估算熱泵熱水系統源投資報酬(EROI)值為1.45~5.55,能源回收期約為0.22年至2.16年,表示熱泵熱水系統從生命週期的角度來檢視能源效率是具有效益的。由於目前熱泵熱水系統對環境最大的負擔來源是電力的使用,若未來能提高再生能源發電比例、降低臺灣電能含碳濃度,或者提高熱泵能源生產效率,均能降低熱泵熱水系統對環境的負面影響。 / The purpose of this study is to apply life cycle assessment (LCA) and net energy analysis to explore the environmental impacts of the heat pump water heater in Taiwan. In order to achieve this objective, domestic data inventory was gathered from local heat pump industry in Taiwan through questionnaires including input of energy, product output and waste, etc. The SimaPro7.3 program and two impact assessment methods including Eco-Indicator 95, EPS 2000 were utilized to evaluate the environmental impact of the heat pump water heater. Also, we used net energy analysis such as energy return on investment and energy payback time, and estimated the life-cycle CO2 emissions to see whether if the heat pump water heater has its energy efficiency. In addition, the sensitivity analysis was performed by varying renewable energy generation portfolio and the heat pump energy efficiency ratio. Emprical results of two impact assessment methods (Eco-indicator 95 and EPS 2000) show that the main impact on environment of heat pump water heater is from operation phase. When operating the heat pump water heater, it needs to consume electricity which is generated from fossil fuel and caused the environmental impact. Compared with the electric water heater, the environmental impact degree of heat pump water heater is much smaller. In Eco-indicator 95 method, gas water heater has less influence on the environment than heat pump water heater; however, heat pump water heater is the most environment-friendly system in EPS 2000 method. That is because gas is a kind of nonrenewable resource. From the viewpoint of resource stock, gas indeed influence “Depletion of reserves” of environmental impact. By utilizing net energy analysis, the estimated energy return on investment (EROI) of heat pump water heater is 1.45~5.55, and energy payback time is 0.22~2.16 years. It indicates that heat pump water heater has significant benefit from life-cycle perspective. The main impact to environment by heat pump water heater is essentially derived from electricity input. To mitigation this environmental issue, one can reduce environmental impact by increase the proportion of renewable energy generation, and reducing the electricity CO2 emission. Furthermore, improving the energy efficiency of the heat pump would also helpful.
38

Účinnost zdrojů a nepřímotopný ohřev teplé vody / Boiler efficiency and indirect heating of hot water

Matůšů, Ondřej January 2019 (has links)
This diploma thesis deals with efficiency of heat sources and indirect heating of hot water. First part of this thesis is about heating of hot water, particulary indirect heating of hot water and it is all summarized in theoretical knowledge section. Second part deals with central heating and indirect heating of hot water in four floor flat house. The heat source for this object is cascade of two gas condensing boilers. In this building there are mostly used panel radiators. In the last, third part, I experimentaly deal with operational efficiency of heating sources with heating of hot water.
39

Sustainable Construction Practices of Intentional Communities: a Pilot Investigation in Loudoun County, Virginia and Frederick County, Maryland

Shedd, Jason Lee 11 August 2012 (has links)
This project investigated the sustainability of homes within three intentional communities. Semi-structured interview and photographic walkthroughs examined the variability of architectural and technological approaches toward sustainability. These include: passive solar design, green roofs, radiant flooring, composting toilets, ground assist heat pumps, solar water heaters, multiamily units and modular construction. It was hypothesized that variation in sustainable construction is related to socioeconomic status and that economics would be a constraint. This project investigated whether communities were transmitting their practices to wider society, if individuals were copying vernacular architecture and if architectural practices followed individual beliefs regarding sustainability. It was found that the Internet is the main method of conveying these practices; that variability was tied less to individual beliefs than to the communities’ institutional documents; and that copying vernacular architecture was for aesthetics not sustainability. Intentional communities are good models for sustainable development, but knowledge transmission is limited.

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