Thesis (M.S. - Renewable Natural Resources)--University of Arizona, 1984. / Includes bibliographical references (leaf 69).

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Este trabalho propõe um método com objetivo de avaliar a eficiência energética de aquecedores de água residenciais de acumulação elétricos. Os aquecedores foram submetidos a um ciclo de operação simulando uma condição de uso para o cálculo da eficiência. Este ciclo de duração de um dia é composto pelas fases: produção de água quente, reaquecimento e manutenção da temperatura interna. O método foi aplicado no programa experimental e permitiu a identificação de diversos parâmetros referentes ao funcionamento dos aquecedores, tais como: perda passiva por 24 horas, produção de água quente, tempo de reaquecimento, variação da temperatura interna da água e a sua eficiência energética. / This work proposes a method with objective of evaluating the energy efficiency of electrical residential storage water heaters. The heaters were submitted to an operation cycle simulating a use condition for the calculation of the efficiency. This cycle with duration of one day is composed by the phases: hot water withdrawal, temperature recovery and standby thermal loss. The method was applied in the experimental program and it allowed the identification of several parameters regarding the operation of such heaters as: standby thermal loss per 24 hours, hot water rate output, reheating time, cyclic variation of the temperature and its energy efficiency.

Thesis (M. Sc.) (Hons) -- University of Western Sydney, 2003. / "A thesis submitted in partial fulfilment of the requirements for the degree of Master of Science (Hons.), University of Western Sydney, Australia, Water Research Laboratory, Centre for Water & Environmental Technology." Includes bibliography : leaves 168 - 183 and appendices.

Este trabalho propõe um método com objetivo de avaliar a eficiência energética de aquecedores de água residenciais de acumulação elétricos. Os aquecedores foram submetidos a um ciclo de operação simulando uma condição de uso para o cálculo da eficiência. Este ciclo de duração de um dia é composto pelas fases: produção de água quente, reaquecimento e manutenção da temperatura interna. O método foi aplicado no programa experimental e permitiu a identificação de diversos parâmetros referentes ao funcionamento dos aquecedores, tais como: perda passiva por 24 horas, produção de água quente, tempo de reaquecimento, variação da temperatura interna da água e a sua eficiência energética. / This work proposes a method with objective of evaluating the energy efficiency of electrical residential storage water heaters. The heaters were submitted to an operation cycle simulating a use condition for the calculation of the efficiency. This cycle with duration of one day is composed by the phases: hot water withdrawal, temperature recovery and standby thermal loss. The method was applied in the experimental program and it allowed the identification of several parameters regarding the operation of such heaters as: standby thermal loss per 24 hours, hot water rate output, reheating time, cyclic variation of the temperature and its energy efficiency.

The work generally deals with the possibilities of preparing hot water in household and analyzes saving posibilities. At the beginning of work the history of hot water preparation is briefly indicated. Chapter 3 deals with different ways of heating. Described in more detail electric storage heating is in chapter 4, where can be found the effect of heating to the power network, especially to the daily load diagram. The following are the information of the tariff policy, as a tool for motivation of consumers, for using the storage heating. In the next part, beginning with the fifth chapter, is written about the possibility of energy saving by means of intelligently controlled boiler. That eliminates the disadvantage of storage heating, which are the tank thermal losses. Heating is based on a certain regularity in the behaviour of the user and manages the preparation of water according to expected consumption. The sixth chapter then contains design of own algorithm for economical control of heating and also energetic and economic assessment of potential savings.

This diploma thesis describes the detailed design of heating and hot water heating for a family quest-house. At first the reader is introduced to the designed building, its design and construction elements. The thesis presents the calculation procedure and design of the heating system. This consists of designing radiators, the heat source, the circulating pumps, regulations of the heating system and the design of its security elements. The thesis also describes the design of the heat exchanger for hot water and security. In conclusion, an evaluation of operating costs with the recommended solution for their reduction. The thesis also includes drawing documentation of structural drawings, heating and unrolled schema that is mentioned in the attachment.

This master’s thesis elaborates a design of water heating and heating system for a building of a rehabilitation center in Horný Hričov. The theoretical section describes operational efficiency of gas boilers and associated calculation methods. The experimental section covers measurements of condensing gas boiler at various temperatures of heating water conducted in university laboratory. Operational efficiency was then calculated using indirect method based on the measurement results. Subsequently, calculated values and values measured by an operational efficiency analyzer were compared. The comparison revealed minor deviations in operational efficiency values and different values of condensing heat utilization between the calculations and the analyzer results. The analytical section of the thesis consists of complex designs of two versions of the heating system and the water heating. The first design version uses condensing gas boilers as a heat source while the second version uses a water-air heat pump instead. The project section of the thesis is executed in the scope for a building permit and consists of a technical report and a design documentation.

In dieser Arbeit wird eine einheitliche physikalische Beschreibung des Feuchtespeicherverhaltens poröser Materialien gegeben, und ein anwendungsorientiertes Modell daraus abgeleitet. Insbesondere wird die Hysteresis der Feuchtespeicherung berücksichtigt. Die thermodynamischen Grundlagen der Feuchtespeicherung werden vollständig abgeleitet. Die Energie des kondensierten Wassers wird durch die Energie der freien Flüssigphase zuzüglich einer Porenwechselwirkungsenergie dargestellt. Um das Kondensationsverhalten zu beschreiben, wird ein thermodynamisches Kondensationspotential eingeführt; dabei werden ein Ungleichgewicht zwischen Kondensatphase und Wasserdampf sowie mehrere unabhängige Wassergehalte im Porensystem zur Darstellung der Hysteresis berücksichtigt. Für verschiedene in der Literatur beschriebene Sorptionsprozesse wird mit einheitlichen Zustandsgrössen das Kondensationspotential berechnet. Die Hysteresis wird als verzögerte Bewegung des Systemzustandes in der Berg- und Tallandschaft des Kondensationspotentials interpretiert. Es wurden an 11 Materialien Sorptionsmessungen im hygroskopischen Luftfeuchtebereich (0-92% RH) durchgeführt: Eine Adsorptionskurve und mehrere Desorptionskurven, sowie eine Langzeitmessung der Feuchteaufnahme bei 92% RH. Aus dem Adsorptions-Desorptionsverhältnis entnimmt man, dass der Hysteresis-Effekt typischerweise etwa 20% ausmacht. Mit den Messungen werden für alle Materialien das Modell der unabhängigen Domänen, das hysteretische thermodynamische Kondensationspotential und das Sorptionskurvensystem parametrisiert. Die Feuchteaufnahme bei dem Langzeitexperiment lässt sich durch eine bimodale Exponentialfunktion beschreiben. Die Kurven von hygroskopischer Adsorption und Desorption werden durch analytische Funktionen angenähert. Die Steigungen der Zwischenkurven werden aus den Steigungen der Hauptkurven berechnet. In gleicher Weise wird auch der überhygroskopische Bereich dargestellt, unter Zuhilfenahme externer Messdaten. Schliesslich ergeben sich zwei getrennt parametrisierte, aneinander angrenzende Sorptionsschleifen für den hygroskopischen und den überhygroskopischen Bereich. Alle Parameter werden so angepasst, dass eine grösstmögliche Übereinstimmung mit dem Domänenmodell erzielt wird.:1. Einleitung 2. Allgemeine Thermodynamik der Feuchtesorption 3. Sorptionsmodelle in einheitlicher Beschreibung 4. Experimentell untersuchte Materialien 5. Parametrisierung von Modell und Sorptionskurven 6. Zusammenfassung A.1. Details zur Theorie A.2. Details zum Experiment A.3. Details zur Parametrisierung / This work gives a unified physical description of moisture storage in very different porous materials and derives an application-oriented model, especially the hysteresis of moisture storage has been investigated extensively. A full derivation of the thermodynamics of moisture sorption is given. The energy of condensed water is described by the energy of the free liquid plus a pore interaction energy. To describe the condensation behaviour, a thermodynamic condensation potential is introduced. It takes into account a non-equilibrium between condensed water and water vapour as well as several independent moisture contents in the liquid phase to describe the hysteresis. For many different sorption processes described in literature the condensation potential is derived, using always the same state variables. Hysteresis is interpreted as a delayed movement of the system in the hill-and-valley-landscape of the condensation potential. Sorption measurements have been performed for 11 different materials in the hygroscopic region (0-92% RH). One adsorption curve and several desorption curves and also the time dependent moisture sorption at 92% RH in a long-time experiment have been measured. From the adsorption-desorption ratio it can be concluded that the influence of hygroscopic hysteresis is typically about 20%. From the measurement results, for all materials the model of independent domains, the hysteretic condensation potential and the sorption curve system are parameterised. The moisture uptake of the long-time experiment can be described by a bimodal exponential function. The curves of hygroscopic adsorption and desorption are approximated by analytical functions. The slopes of the intermediate curves are calculated from the slopes of the main curves. In the same way the overhygroscopic region is approximated, using external measurement results. Finally a model is presented with two neighbouring sorption loops, one for the hygroscopic, one for the overhygroscopic region. All parameters are fitted to the predictions of the domain model.:1. Einleitung 2. Allgemeine Thermodynamik der Feuchtesorption 3. Sorptionsmodelle in einheitlicher Beschreibung 4. Experimentell untersuchte Materialien 5. Parametrisierung von Modell und Sorptionskurven 6. Zusammenfassung A.1. Details zur Theorie A.2. Details zum Experiment A.3. Details zur Parametrisierung