Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (M.S.) -- Worcester Polytechnic Institute. / Keywords: uniformity of heating; optimization; optimal process; modeling; microwave pulsing; microwave heating; FDTD method; coupled problem. Includes bibliographical references (leaves 50-59).

No description available.

A numerical model has been developed for the dynamic simulation of heat and radiation transfer from lamps and ballasts in an enclosure. The model, named LITEAC1, calculates temperatures, cooling loads and illuminances at each simulation time step. LITEAC1 is an improvement upon existing models in the literature in the following aspects: it performs dynamic simulation for all nodes without assuming that some nodes are massless; it calculates illuminances on room surfaces; and it runs faster on a desktop computer. In order to refine the simulation of the two-way interaction between lighting and HVAC systems, a fluorescent lamp positive column discharge model, named LAMPPC, has been incorporated into LITEAC1 to improve calculation of the conversion of input electrical energy into light, thermal radiation and heat. LAMPPC employs established principles in plasma physics to quantify the energy conversion processes.

No description available.

This thesis investigates the design of domestic glazed spaces in the United Kingdom, by studying the effect of a range of variables on the thermal properties of glazed spaces, in order to achieve a thermally comfortable environment while minimising the use of energy for heating and cooling. Earlier research work on domestic glazed spaces has concentrated on optimising the design of the space as a mechanism for reducing the space heating load of the parent house. Computer based dynamic thermal simulation is used in this study as the method of assessment and the variables tested are; glazing type, orientation and the degree of integration of the glazed space with the parent building. Unshaded, unventilated, and unheated, glazed spaces were found to be thermally comfortable for only a quarter to a third of the hours of possible use whatever the form, orientation or glazing type. Generally the higher the insulating value of the glazing the fewer the number of comfortable hours for all orientations and arrangements, due to discomfort being caused by high temperatures, even though the weather data used for the simulations only rose above 27'C for 25 hours during the course of the year. Further studies showed that significant reductions in the number of hours experiencing high temperatures could be achieved by the use of buoyancy driven ventilation. The studies indicated that glazed spaces integrated into the house plan tended to experience high temperatures for long periods but that the peak temperatures were much lower than those experienced for shorter periods in the exposed spaces. The effect of ventilation on overheating was therefore more marked in the integral than in the exposed glazed spaces. A study of the effects of roof shading blinds indicated that internal blinds had minimal effect in reducing high temperatures. External blinds had a greater effect than ventilation and a combination of external roof blinds and ventilation appears to provide the best strategy for the control of high temperatures. Studies on space heating loads for the houses and glazed spaces indicated wide variations in the heating loads of the glazed spaces depending predominantly on the insulating properties of the glazing. In terms of the reduction in the space heating load for the parent house, the thermal simulation results predict very little change due to the presence of the glazed space. A study on the effect of increasing the thermal storage properties of the floor construction of the glazed spaces, by substituting a clay tile finish for the original thin carpet layer, in order to reduce high temperatures proved inconclusive with minimal changes in the number of comfortable hours experienced. An investigation of thermal comfort during the Winter indicated that low surface temperatures did not reduce resultant temperatures below the lower limit of the comfortable range in the glazed spaces, during the heated period.

The development of products which enable passive solar-energy air-heating to be integrated into the heating strategies of public, commercial and industrial buildings is described. These buildings are, in general, only occupied significantly during the day; consequently the bulk of heating demand coincides with the period of solar gain. In these circumstances collected solar heat should be delivered with the minimum of delay. The design and operation of units which are capable of supplying solar heated air in this manner is outlined. These are passive, naturalcirculation air-heating collectors, also known as natural-convection air-heaters, or thermosyphoning air panels. Four methods of retrofitting such solar collectors to non-domestic buildings have been identified, one of which, the overcladding collector, has not been proposed previously. Problems associated with the successful installation and operation of these units have also been considered. The relative merits of a number of methods of testing passive solarenergy air-heating collectors have been investigated. A method of determining instantaneous collector efficiency based on the measurement of glazing temperature, inlet and outlet air temperature, ambient temperature and insolation has been developed. Three novel design proposals have been presented: i) a collector constructed with the insulation fitted outside, rather than inside, so that the metal body of the collector may provide more symmetrical heating of the air flow than the conventional arrangement, ii) an absorber which consisted of parallel ducts to increase the rate of heat transfer to the air, heating it symmetrically, (iii) a hinged air-deflector for conversion from the heating to the ventilation mode.

No description available.

This research focussed on the identification, evaluation and recommendation of passive design strategies suitable for housing design in hot and dry climates in India. The term 'passive' refers to those design techniques which, in order to enhance thermal comfort, utilize the favourable and mininimize the unfavourable elements of the local climate. The objective of the research was to determine means by which reliance on mechanical means of achieving comfort and associated socio-economic costs can be minimized. The thesis is divided into two parts. The first part identifies and evaluates the passive design techniques used in the dwellings of pre-industrial and post-industrial cities located in hot and dry region in India. Climate, environmental problems (primarily cooling), and indoor comfort criteria were analysed to establish preliminary criteria for evaluating the thermal performance of design techniques. The main objective was to enable designers to identify those techniques which can be used in contemporary dwelling designs. The second part proposes strategies to incorporate passive techniques in contemporary housing design. General strategies recommended at various levels of design include the following: -minimize solar gain -minimize conductive heat flow -promote ventilation -minimize internal heat gains -promote radiant cooling -delay periodic heat flow -promote evaporative cooling -control high velocity wind -control glare These strategies, which recognize the comfort-related needs of dwelling occupants, promote the use of local construction practices. The application of passive techniques presents architects with a considerable scope for creativity in housing design. However, at the outset, it is necessary to define priorities in the selection of design strategies, and to ensure these priorities are addressed through each level of design. The strategies selected in this thesis emphasize the need for minimizing heat gain during day time, and maximizing heat loss at night. It is concluded from this research that the application of passive techniques in contemporary housing design allows for maintenance of most thermal comfort needs, thereby reducing reliance on mechanical means of control. At the same time, the use of passive techniques provides a potential for the housing designs to respond effectively to certain socio-cultural needs of the occupants. / Applied Science, Faculty of / Architecture and Landscape Architecture (SALA), School of / Received degree under the name Bhatia / Graduate

No description available.