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

xviii, 170 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / New residence halls differ from their predecessors because of sophisticated systems, concern for energy efficiency, and attention to student satisfaction. Nevertheless, older facilities represent the bulk of housing stock on many campuses. A literature review revealed few recent studies related to student housing. This thesis questions how residence hall age influences occupant perceptions and actions related to comfort and energy consumption. The study took place in two residence halls, built in 1963 and 2006, and entailed an occupant survey of 103 residents as well as the collection of thermal and utility data. Survey results did not show a significant difference in occupant behaviors between the older and newer buildings. Thermal measurements in both buildings fell inside and outside the ASHRAE Comfort Zone, which supported occupant perceptions. Findings indicate a lack of student awareness of energy conservation strategies. Furthermore, greater consistency in campus utility metering would enable more accurate building performance comparisons. / Committee in Charge: Dr. Alison G. Kwok, Chair; Dr. Mark L. Gillem; Fred Tepfer

D.Phil. (Environmental Management) / Clean, efficient, and low carbon energy services are crucial to the sustainable functioning of a household unit. Therefore, this study explores a vital query on the best pathway to achieve universal modern energy access in low-income South African households, based on information gathered from interviews in urban settlements. The thesis is based on published papers touching on thematic areas of household energy access – from baseline assessments to appraisal of modern energy programmes. A set of factors that are necessary for successful introduction and uptake of clean energy are identified for consideration by policy makers. Results indicate widespread use of paraffin and solid fuels in inefficient combustion technologies among low-income urban households even in the rich Johannesburg metropolis. In the absence of formal employment, some township residents use the basic fuels and conventional combustion technologies for productive purposes. Growth in the thermal-intensive informal businesses could be achieved faster through provision of efficient and reliable alternative energy technologies and better operational environment. This study has highlighted the undue risk borne by energy-poor households in the performance of the day-to-day energy tasks. The results show that household risk is positively correlated with the quality and quantity of energy used, with paraffin being the most risky fuel and the apparent risk being larger in non-electrified households. The affected communities have expressed a desire to adopt cleaner and safer forms of energy for residential and economic uses. It is incumbent upon the government and relevant role players to create enabling systems for acquisition of the preferred modern energy streams. An LPG intervention project in the City of Tshwane has demonstrated the inherent potential for modern energy to transform the socioeconomics and overall wellbeing of a family. The impact of such energy interventions could be improved through better-designed energy delivery models that cater for residential and productive needs, leading to sustainable communities. Education and income have been shown to be good precursors for modern energy uptake. Therefore, efforts towards sustainable energy for all should not only focus on indigent assistance and expansion of electrification, but also be intertwined with policies addressing skills need and better household incomes.

Installation and utilization of residential distribution transformers has not changed substantially over a long period of time. Utilities typically size their transformers based on a formula that takes into account broadly what types and how many dwellings will be connected. Most new residential dwellings feature 200 Amp service per household with an anticipated energy demand of under 20,000 kWh per year. Average electrical energy consumption varies from state to state but averages to 11,280 kWh per year. Energy demand is expected to fall into a typical residential load curve that shows increased demand early in the morning, then decreasing during the day and another peak early to late evening. Distribution transformers are sized at the limit of the combined evening peak with the assumption that the transformer has enough thermal mass to absorb short overloads that may occur when concurrent loading situations among multiple dwellings arise. The assumption that concurrent loading is of short duration and the transformer can cool off during the night time has been validated over the years and has become standard practice. This has worked well when dwelling loads follow an averaging scheme and low level of coincidence. With the arrival of electric vehicles (EV's) this assumption has to be reevaluated. The acquisition of an electric vehicle in a household can drive up energy demand by over 4000 kWh per year. Potentially problematic is the increased capacity of battery packs and the resulting proliferation of Level 2 chargers. The additional load of a single Level 2 charger concurring with the combined evening peak load will push even conservatively sized distribution transformers over their nameplate rating for a substantial amount of time. Additionally, unlike common household appliances of similar power requirements such as ovens or water heaters, a Level 2 battery charger will run at peak power consumption for several hours, and the current drawn by the EVs has very high levels of harmonic distortion. The excessive loading and harmonic profile can potentially result in damaging heat build-up resulting in asset degradation. In this thesis I present a device and method that monitors pole mounted distribution transformers for overheating, collect and wirelessly upload data and initiate commands to chargers to change output levels from Level 2 to Level 1 or shut down EV charging altogether until the transformer returns into safe operational range.

No description available.

In previous studies, the analysis of ball mill operating parameters and their effects on breakage phenomena has been limited to homogeneous materials. Though these studies have proven to be an asset in predictions of product size distributions and mill scale-up, they have not addressed the primary role of grinding, i.e. liberation. The present investigation analyzes the effect of ball mill operating parameters on the breakage rates of both liberated and composite material. The operating parameters studied include mill rotational speed, ball size, mill charge, and wet versus dry grinding. Breakage rates have been determined experimentally utilizing a SEM-IPS image analyzer. The mineral sample used was acquired from ASARCO's Young Mine which is located in Jefferson City Tennessee. It was a binary ore consisting of sphalerite and dolomite. Batch grinding experiments were conducted to provide breakage rates for the various composition classes. Breakage rates were then normalized with respect to energy to see if the changes in breakage rates associated with mill operating parameters were due to changes in breakage kinetics, or simply a function of energy input. The energy normalized data indicates that the free dolomite breakage rates tend to normalize with respect to energy in the case of varying interstitial fillings. Furthermore, changes in mill rotational speed tend to provide energy normalizable breakage rates for both free dolomite and sphalerite. In all other cases, analysis of the breakage rates and energy-specific breakage rates indicate that a change in breakage kinetics may be occurring. In general, particles containing a high proportion of sphalerite are more apt to break under impact conditions. On the other hand, particles containing a large proportion of dolomite were found to prefer attrition breakage conditions. / Master of Science / incomplete_metadata

The purpose of this study was to determine intermediaries’ perceptions of barriers and incentives to innovative, energy efficient housing in Iowa. Data was collected by two surveys. The questionnaire for the first survey collected data from 102 communities in Iowa. Respondents were asked to determine the number of building permits issued for all new single family dwellings between 1975 and 1985 as well as the number of permits issued that were for passive solar, active solar, or earth sheltered housing. A rate of adoption was calculated for each community. The second questionnaire surveyed housing intermediaries drawn from the 102 communities included in the first survey. The sample consisted of 481 builders, building inspectors, realtors, lenders, and solar suppliers. Intermediary groups differed in their perceptions of barriers and incentives to innovative, energy-efficient housing. Significant differences were found among the intermediaries for whether state mandated solar standards would reduce the risk of inspection of solar energy houses and whether risky resale potential acts as a barrier to building solar energy housing. The major barriers were the "first costs" associated with building active solar and earth sheltered housing and the lack of skills among subcontractors to build active solar and earth sheltered housing. There was no significant relationship between rate of adoption among communities and their location in the state. There was, however, a significant relationship between category of building official and rate of adoption among communities. Communities with a high rate of adoption did not cluster in any one quadrant of the state. Additional differences among intermediaries occurred between lenders who had financed innovative energy efficient housing and lenders who had not. Lenders who had not financed solar or earth sheltered housing perceived the barriers to be greater than those who had. There were fewer differences in perceptions among solar/earth sheltered builders and nonsolar/earth sheltered builders. In conclusion, variability in perceptions among intermediaries on the barriers and incentives to innovative, energy efficient housing impact on the rate of adoption in communities in Iowa. / Ph. D.

Call number: LD2668 .T4 1979 D65 / Master of Arts

In the process of electricity generation, water is used as the working fluid to transport energy from the fuel to the turbine. This water has to be ultrapure in order to reduce maintenance cost on the boilers. For the production of ultrapure water, a desalination process is used. This process consists of an ultrafiltration pretreatment section, two reverse osmosis stages and a continuous electrodeionisation stage. Reverse osmosis desalination plants are, however, inherently inefficient with a high specific energy consumption. In an attempt to improve the efficiency of low recovery seawater applications, energy recovery devices are installed on the brine outlet of the reverse osmosis stages. The energy recovery device recovers the energy that is released through the high pressure brine stream and reintroduces it to the system. The investigated desalination process has a fresh water feed with a salinity of 71 ppm and is operated at recoveries above 85%. The plant produces demineralised water at a salinity lower than 0.001ppm for the purpose of high pressure boiler feed. A thermodynamic analysis determined the Second Law efficiencies for the first and second reverse osmosis sections as 3.85% and 3.68% respectively. The specific energy consumption for the reverse osmosis plants is 353 Wh/m3 and 1.31 Wh/m3. This was used as the baseline for the investigation. An exergy analysis determined that energy is lost through the brine throttling process and that a pressure exchanging system can be installed on all reverse osmosis brine streams. Energy recovery devices are untested in high recovery fresh water applications due to the low brine pressure and low brine flow. It was determined that pressure exchanging systems can reduce the specific energy consumption of the first reverse osmosis stage with 12.2% whereas the second RO stage energy consumption can be improved with 7.7%. The Second Law efficiency can be improved by 25.6% for the first reverse osmosis stage while the efficiency is improved with 18.1% for the second stage. The optimal operating recovery for the PES is between 80% and 90%. / MIng (Chemical Engineering), North-West University, Potchefstroom Campus, 2015

In the process of electricity generation, water is used as the working fluid to transport energy from the fuel to the turbine. This water has to be ultrapure in order to reduce maintenance cost on the boilers. For the production of ultrapure water, a desalination process is used. This process consists of an ultrafiltration pretreatment section, two reverse osmosis stages and a continuous electrodeionisation stage. Reverse osmosis desalination plants are, however, inherently inefficient with a high specific energy consumption. In an attempt to improve the efficiency of low recovery seawater applications, energy recovery devices are installed on the brine outlet of the reverse osmosis stages. The energy recovery device recovers the energy that is released through the high pressure brine stream and reintroduces it to the system. The investigated desalination process has a fresh water feed with a salinity of 71 ppm and is operated at recoveries above 85%. The plant produces demineralised water at a salinity lower than 0.001ppm for the purpose of high pressure boiler feed. A thermodynamic analysis determined the Second Law efficiencies for the first and second reverse osmosis sections as 3.85% and 3.68% respectively. The specific energy consumption for the reverse osmosis plants is 353 Wh/m3 and 1.31 Wh/m3. This was used as the baseline for the investigation. An exergy analysis determined that energy is lost through the brine throttling process and that a pressure exchanging system can be installed on all reverse osmosis brine streams. Energy recovery devices are untested in high recovery fresh water applications due to the low brine pressure and low brine flow. It was determined that pressure exchanging systems can reduce the specific energy consumption of the first reverse osmosis stage with 12.2% whereas the second RO stage energy consumption can be improved with 7.7%. The Second Law efficiency can be improved by 25.6% for the first reverse osmosis stage while the efficiency is improved with 18.1% for the second stage. The optimal operating recovery for the PES is between 80% and 90%. / MIng (Chemical Engineering), North-West University, Potchefstroom Campus, 2015