published_or_final_version / Architecture / Doctoral / Doctor of Philosophy

This study determined winter and summer shading coefficients for six commonly used landscape trees in Tucson using a photographic dot-matrix method. Tree types were developed from this data reflecting canopy density, shape, and foliage periods, then applied to SPS and MICROPAS computer programs to model effects of tree shade on annual energy loads for three residential construction types. Statistical analysis showed pruning to have a significant effect for 5 of the 6 species tested. Significant differences were also found among species and within species due to seasonal effects in foliage density. Shading scenarios manipulated the number and location of tree types were modeled. Greatest net annual savings were from 3 African sumac trees located on the west side of a masonry house typical of the 1950s (121). Shade from tree species found to have significantly different shading coefficients (10%) did not substantially increase energy savings ($5-12).

The objectives of the study were to examine and quantify the relationship between vegetation and the thermal performance of residences in a hot arid environment. Also explored were structural and human influences on residential energy consumption. A primary goal was to determine how much energy savings could be realized through strategic planting of vegetation. This study sought to validate previous simulation and modeling studies that documented annual savings of 2-11% on residential cooling loads. Also examined was whether shrubs and grass could provide a benefit similar to that of trees, assessing the importance of evapotranspiration versus shading. An empirical study was conducted using 105 existing homes in the metropolitan area of Tucson, Arizona. Data included construction type, amenities, living habits of occupants, and energy consumption for heating and cooling over a two-year period. These data were analyzed with a combination of bivariate and multivariate analyses to examine direct correlations between specific variables and energy consumption and the relative importance of each variable. These analyses were unable to document any measurable savings in summer cooling loads as a result of vegetation adjacent to the house, and the presence of trees actually increased the winter heating load by 2%. While trees provide important shading benefits, and can reduce the direct solar gain through the windows of a house, analysis demonstrated that structural and human factors were the most important aspects in residential energy consumption. The size of the house is of primary importance. Houses with evaporative cooling consumed significantly less energy than those with air conditioning. Thermostat settings and habits regarding thermostat operation were the most critical human factors. Occupants who adjusted their thermostats a few degrees cooler in winter and warmer in summer realized measurable savings. Occupants who turned their heating and cooling equipment off when they were not home used significantly less energy for heating and cooling. These factors far outweighed any impact from vegetation on annual energy consumption. While trees should not be considered as a primary means of reducing annual energy consumption, properly placed vegetation can provide aesthetic benefits and increase the thermal comfort of the occupants.

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Includes bibliographical references (leaves 116-118). / With the growing awareness of the rapid disappearance of the global fuel resources, energy conservation became an issue of general concern. Prompted by the results of studies done in the 1970's--which show a marked increase of energy consumption per square foot of office space over the years, as well as differences in consumption between buildings of different periods -- this thesis looks at the features that determine the considerable variation in energy consumption in office buildings from the beginning of the century to our days. An overview of the historic evolution of the highrise offices presents the events that influenced the change in energy performance.The elements that determine the energy use in a building, like its orientation, exterior envelope, interior design, and mechanical systems, are individually analyzed to present a detailed picture of their role. Their characteristics in the periods before and after the second world war are then compared, showing how they determined the energy performance of buildings of the respective periods. / by Nora Anca Niculin. / M.Arch.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Bibliography: p. 104-109. / There are two distinguishable parts to this thesis. Part I is a discourse on architectural representation. It defines the theoretical boundary for Part II, research on a particular spatial representation system, physical models, and their use as a design aid. In Part I, representation is discussed as it pertains to the design process. An opinion is built around the excessive 'visual' nature of the topic. The many types of representation systems are described. Finally, a brief historical survey, as well as two current design processes provide insight into applications of these systems. Part II is the documentation of a research project that attempts to visualize physical phenomena (energy behavior) as they act on physical models representative of architectural form. A statement is put forth postulating a design approach that addresses energy behavior in a 'qualitative' sense based on its comprehension through these established visualization techniques. A procedure for testing physical phenomena on models is described and finally, the documentation of such tests for wind, solar shading, convection and light are presented. A conclusion forecasts potential applications of this research. The multi-disciplinary exploration of visual communications and energy conscious design is addressed in the content, as well as the communicative technique and medium of this presentation. The author is responsible for reproducing all the images in this book. Reproductions from other sources were copied photographically. In its original form several pages were printed in offset. This process was completed entirely by the author, from original photograph to pasteup, printing preparation and running the press. An experimental video production is being prepared as well. / by Donald Alberto. / M.S.

Thesis (M.Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Bibliography: p. 202-205. / Until now, passive solar energy has been overlooked as a viable alternative for home heating in urban subsidized housing. Rather ironically, in housing whose residents could most benefit from the use of solar energy, such concepts and technologies are not utilized. This thesis demonstrates how passive solar heating and energy conscious design can be economically implemented in low- and moderate-income subsidized housing. The research and design work presented explain the well-integrated system of natural environmental tempering that includes passive solar heating, natural daylighting, natural ventilation and energy conservation. A crucial aspect of the thesis is the method of dollar-for-dollar tradeoffs that is used to keep the cost of the natural environmental tempering components within the strict budget constraints of subsidized housing. Also, the housing is designed with careful attention paid to the needs of the inhabitants. Thus, in addition to the energy concerns, the design reflects new attitudes toward subsidized housing. The resulting solar architecture is a significant answer to the need for economical public housing that allows low-income urban residents to benefit from the sun's abundant energy. / by Karen M. Duncan. / M.Arch.

Thesis (M.Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Bibliography: p. 199-203. / by James E. Rosen. / M.Arch.

Thesis. 1977. M.Arch.--Massachusetts Institute of Technology. Dept. of Architecture. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Bibliography : leaves 98-100. / by James S. Day. / M.Arch.

Predicted cooling system performance plays an important role in choices among alternative system selections and designs. When system performance is expressed in proper indicators such as "overall system energy consumption" or "overall system efficiency", it can provide the decision makers with a quantitative measure of the extent to which a cooling system satisfies the system design requirements and objectives. Predictions of cooling system energy consumption and efficiency imply assumptions about component performance. Quantitative appraisal of the uncertainty (lack of knowledge) in these assumptions can be used by design practitioners to select and design systems, by energy contractors to guarantee future system energy cost savings, and codes and standards officials to set proper goals to conserve energy. Our lack of knowledge has different sources, notably unknown tolerances in equipment nameplate data, and unpredictable load profiles. Both cause systems to under-perform current predictions, and as a result decrease the accuracy of the outcomes of energy simulations that commonly are used to verify system performance during the design and construction stages. There can be many other causes of unpredictable system behavior, for example due to bad workmanship in the installation, occurrence of faults in the operation of certain system parts, deterioration over time and other. These uncertainties are typically much harder to quantify and their propagation into the calculated energy consumption is much harder to accomplish. In this thesis, these categories of failures are not considered, i.e. the treatment is limited to component tolerances and load variability. In this research the effects of equipment nameplate tolerances and cooling load profile variability on the overall energy consumption and efficiency of commonly used commercial cooling systems are quantified. The main target of this thesis is to present a methodology for calculating the chances that a specific cooling system could deviate from a certain efficiency level by a certain margin, and use these results to guide practitioners and energy performance contractors to select, and guarantee system performances more realistically. By doing that, the plan is to establish a systematic approach of developing expressions of risk, in commercial cooling system consumption and efficiency calculations, and thus to advocate the use of expressions of risk as design targets. This thesis makes a contribution to improving our fundamental understanding of performance risk in selecting and sizing certain HVAC design concepts.

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