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Techno-Economic And Sustainability Analysis Of Renewable Natural Gas (Rng) Production, Eesha Bhattacharjee

USF Tampa Graduate Theses and Dissertations

Natural Gas (NG) is one of the major sources of energy currently used in the United States. Its major applications include generating electricity, domestic, and industrial heating purposes and as a transportation fuel. The largest component of NG is methane, and it contains trace amounts of hydrocarbons, some CO2 and water vapor.

Biogas (produced by anaerobic digestion (AD) of biomass) upgraded to have high purity methane (often termed as biomethane or renewable natural gas) can be used as an alternative to NG. The upgrading techniques may include CO2 separation from the biogas stream or via to a methanation facility where …

Innovative Desalination Systems Using Low-Grade Heat, Chennan Li

USF Tampa Graduate Theses and Dissertations

Water and energy crises have forced researchers to seek alternative water and energy sources. Seawater desalination can contribute towards meeting the increasing demand for fresh water using alternative energy sources like low-grade heat. Industrial waste heat, geothermal, solar thermal, could help to ease the energy crisis.

Unfortunately, the efficiency of the conventional power cycle becomes

uneconomically low with low-grade heat sources, while, at the same time, seawater desalination requires more energy than a conventional water treatment process. However, heat discarded from low-grade heat power cycles could be used as part of desalination energy sources with seawater being used as coolant …

Synthesis And Characterization Of Nanocomposites For Electrochemical Capacitors, Farah Alvi

USF Tampa Graduate Theses and Dissertations

Presently there are deep concerns over the environmental consequences and the consumption of non-renewable energy sources, with the accelerated greenhouse effect, triggered enormous interest in the use of renewable energy sources e.g., solar, hydropower, wind and geothermal. However the intermittent nature of harvesting renewable energy sources has recently gained considerable attention in the alternative reliable, cost effective, and environmentally friendly energy storage devices. The supercapacitor and lithium ion batteries are considered more efficient electrical energy storage devices than conventional energy storage systems.

Both devices have many useful and important applications; they could be an excellent source for high power and …

Crack Analysis In Silicon Solar Cells, Maria Ines Echeverria Molina

USF Tampa Graduate Theses and Dissertations

Solar cell business has been very critical and challenging since more efficient and low costs materials are required to decrease the costs and to increase the production yield for the amount of electrical energy converted from the Sun's energy. The silicon-based solar cell has proven to be the most efficient and cost-effective photovoltaic industrial device. However, the production cost of the solar cell increases due to the presence of cracks (internal as well as external) in the silicon wafer. The cracks of the wafer are monitored while fabricating the solar cell but the present monitoring techniques are not sufficient when …

Smart Grid Functionality Of A Pv-Energy Storage System, Nenad Damnjanovic

USF Tampa Graduate Theses and Dissertations

Renewable Energy will be the key to preserving the Earth's remaining resources and continuing this surge of technological progress that we have experienced this past century. New philosophies of how/when/where energy should be consumed and produced are attempting to improve upon the current grid infrastructure. The massive advancement in communications, renewable and control systems will allow this new-age electric grid to maximize its efficiency while reducing cost. Renewable, "green" energy is now at the forefront of innovation. As the world population increases, there will be a need to free ourselves from natural resources as much as possible. Advanced Energy Storage …

Analyses Of Variable Refrigerant Flow And Exergy In Air Conditioning Systems, Rashid Ali Alshatti

USF Tampa Graduate Theses and Dissertations

This thesis consists of two research problems in the air conditioning (A/C) area. For the first problem, the aim is to model and simulate a variable refrigerant flow (VRF) air conditioning system. The coefficient of performance (COP) for refrigeration or heat pump system is one of the critical parameters for designing an air conditioning system. The modeling of the system components for a VRF cycle under different cooling conditions using R-134a and R-22 as refrigerants was carried out. Calculations were performed by varying different parameters such as condenser and evaporator temperatures, and refrigerant type. The R-134a refrigerant shows a better …

The Conversion Of Low-Grade Heat Into Power Using Supercritical Rankine Cycles, Huijuan Chen

USF Tampa Graduate Theses and Dissertations

Low-grade heat sources, here defined as below 300 ºC, are abundantly available as industrial waste heat, solar thermal, and geothermal, to name a few. However, they are under-exploited for conversion to power because of the low efficiency of conversion. The utilization of low-grade heat is advantageous for many reasons. Technologies that allow the efficient conversion of low-grade heat into mechanical or electrical power are very important to develop.

This work investigates the potential of supercritical Rankine cycles in the conversion of low-grade heat into power. The performance of supercritical Rankine cycles is studied using ChemCAD linked with customized excel macros …