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This thesis explored the energy conservation requirements necessary to retrofit existing historic structures. Residential and small commercial buildings were selected as significant examples. This study discussed and analyzed the historic, climatic, technical, and economic contexts which impact the energy conservation strategy. The major economic and architectural benefits were identified and described. A methodology was developed incorporating feasible retrofitting measures for historic buildings. This included technical and economic ranking of retrofitting measures with prototypical building type studies documenting the theoretical thermal performance before and after incorporation of retrofitting measures. / Department of Architecture

The simple gas turbine engine Operates on the basic Joule-Brayton cycle and it is notorious for its poor thermal efficiency. Several modifications have been made to the simple cycle in order to increase its thermal efficiency but, within the thermal and mechanical stress constrains, the efficiency still ranges between 28 and 35%. However, higher values of energy utilisation efficiency have been claimed in recent years by using low grade heat from the engine exhaust either for district heating or for raising low pressure steam for chemical processes. Both applications are not very attractive in hot countries. The concept of using the low grade thermal energy from the gas turbine exhaust to raise steam in order to drive a steam turbine and generate additional electricity, i. e. the combined power and power or CPP plant would be more attractive in hot countries than the CHP plant. It was hypothesized that the operational parameters, hence the performance of the CPP plant, would depend on the allowable gas turbine entry temperature. Hence, the exhaust gas temperature could not be decided arbitrarily. This thesis deals with the performance of the gas turbine engine operating as a part of the combined power and power plant. In a CPP plant, the gas turbine does not only produce power but also the thermal energy that is required to operate the steam turbine plant at achievable thermal efficiency. The combined gas turbine-steam turbine cycles are thermodynamically analysed. A parametric study for different configurations of the combined gas-steam cycles has been carried out to show the influence of the main parameters on the CPP cycle performance. The parametric study was carried out using realistic values in view of the known constraints and taking into account any feasible future developments. The results of the parametric study show that the maximum CPP cycle efficiency would be at a point for which the gas turbine cycle would have neither its maximum efficiency nor its maximum specific work output. It has been shown that supplementary heating or gas turbine reheating would decrease the CPP cycle efficiency; hence, it could only be justified at low gas turbine inlet temperatures. Also it has been shown that although gas turbine intercooling would enhance the performance of the gas turbine cycle, it would have only a slight effect on the CPP cycle performance. A graphical method for studying operational compatibility, i.e. matching, between gas turbine components has been developed for a steady state or equilibrium operation. The author would like to submit that the graphical method offers a novel and easy to understand approach to the complex problem of component matching. It has been shown that matching conditions between the compressor and the turbine could be satisfied by superimposing the turbine performance characteristics on the compressor performance characteristics providing the axes of both were normalised. This technique can serve as a valuable tool to determine the operating range and the engine running line. Furthermore, it would decide whether the gas turbine engine was operating in a region of adequate compressor and turbine efficiencies. A computer program capable of simulating the steady state off-design conditions of the gas turbine engine as part of the CPP plant has been developed. The program was written in Visual Basic. Also, another program was developed to simulate the steady state off-design operation of the steam turbine power plant. A combination of both programs was used to simulate the combined power plant. Finally, it could be claimed that the computer simulation of the CPP plant makes significant contribution to the design of thermal power plants as it would help in investigating the effects of the performance characteristics of the components on the performance of complete engines at the design and off-design conditions. This investigation of the CPP plant performance can be carried out at the design and engineering stages and thus help to reduce the cost of manufacturing and testing the expensive prototype engines.

Sharply increasing power dissipations in microprocessors and telecommunications systems have resulted in significant cooling challenges at the data center facility level.Energy efficient cooling of data centers has emerged as an area of increasing importance in electronics thermal management. One of the lowest cost options for significantly cutting the cooling cost for the data center is an airside economizer. If outside conditions are suitable, the airside economizer introduces the outside air into the data center, making it the primary source for cooling the space and hence a source of low cost cooling. Full-scale model of a representative data center was developed, with the arrangement of bringing outside air.Four different cities over the world were considered to evaluate the savings over the entire year.Results show a significant saving in chiller energy (upto 50%).The limits of relative humidity can be met at the inlet of the server for the proposed design, even if the outside air humidity is higher or lower than the allowable limits.The saving in the energy is significant and justifies the infrastructure improvements, such as improved filters and control mechanism for the outside air influx.

The purpose of this research is to develop and verify a simplified and concise building simulation model suitable for high-level applications such as preliminary design or for embedding into adaptive control systems. An actual complex modern building and its energy system has been monitored. The monitored energy performance of this building has been compared with the empirical performance predicted by two simulation modeling programs and, alternatively, by a simplified single-zone model. This project is composed of several related tasks. The first component is the monitoring of the energy consumption rates, pertinent environmental data, and load indicators of the new Klaus Advanced Computing Building on the Georgia Institute of Technology's Atlanta campus. The Klaus building was chosen because it represents a typical non-residential building. Subsequently, these findings have been compared with results from DOE-2 and eQUEST, well established energy simulation modeling programs. These comparisons allow for an empirical verification of the modeling program for Atlanta conditions. Finally, a simplified single-zone building model has been developed, and its predictions compared with the empirical data and with the results of the more complex programs. The results verify both the more complex programs and the single-zone model, and also demonstrate the use of a single-zone model for future work and predictions.

Commercial office building occupants are a significant consumer of electricity, and they subsequently contribute a significant amount of greenhouse gases into the environment in the process. An opportunity exists to improve the energy efficiency in existing buildings, and the Energy Star certification program provides both tools to do so and an independent verification of a building's superior energy efficiency. However, only 16% of metro Atlanta's office space has achieved this certification. The intent of the research was to identify the current state of energy efficiency in buildings, and to identify potential obstacles to obtaining the Energy Star certification. Towards this goal, secondary research was conducted among prominent academic journals, as well as numerous professional and governmental organizations and publications. Primary research was conducted through an online survey of Facility Managers, Property Managers, and Building Engineers of Energy Star office buildings and comparable non-Energy Star office buildings in the metro Atlanta area. The survey was conducted mostly using closed-ended questions using a Likert scale so as to provide a basis for statistical analysis among responses, and open-ended questions were also included to identify the current state of energy efficiency practices. The research identified three areas which hold statistically significant differences between Energy Star and directly comparable buildings. An analysis also determined that building age does seem to play a role in the building representatives' responses. Four conclusions were found regarding characteristics of Energy Star buildings themselves. The research also identified five conclusions regarding the expected result when pursuing the Energy Star certification. These conclusions include the best method to achieve the Energy Star certification, the expected energy savings, the expected time spent to achieve the certification, the expected cost to achieve the certification, and the main reasons to recertify the building. Finally, this research highlights innovative practices in other states and cities, such as financial incentives and legislation which require commercial buildings to obtain a building rating. Such innovative practices are currently not employed in the Atlanta metro area, but would be beneficial to both the Atlanta area and individual buildings.

Thesis (M. Sc.)--University of Hong Kong, 1995. / Includes bibliographical references (leaf 96-103).

Thesis (M.P.A.)--University of Hong Kong, 1998. / Includes bibliographical references (leaf 133-137).

Thesis (M.P.A.)--University of Hong Kong, 1998. / Includes bibliographical references (leaves 133-137). Also available in print.

Thesis (M.Sc.)--University of Hong Kong, 1995. / Includes bibliographical references (leaf 96-103). Also available in print.