Thesis (Ph. D.)--Northeastern University, 2008. / Title from title page (viewed July 1, 2009). Graduate School of Engineering, Dept. of Chemical Engineering. Includes bibliographical references (p. 333-347).

Thesis (M.Sc.)--Aberdeen University, 2009. / Title from web page (viewed on July 29, 2009). Includes bibliographical references.

The energy crisis of 2001, high prices for gas and electricity and worries of climate change have caused a growing awareness about energy issues in California. The problems are clear. This paper looks at the next step of finding and implementing solutions. In this case the contribution that solar photovoltaic and solar thermal generation could make toward solving the problem. This paper looks at technological change, the current state of solar energy research, current government policies on solar energy, and finally makes policy recommendations to meet the stated problem.

This paper describes the process that was gone through to develop an averaged model for a three-port converter topology. The converter is based on a modified version of the isolated half-bridge converter topology. This modified topology utilizes three basic modes of operation within a constant-frequency switching cycle to provide two independent control variables. This allows tight control over two of the converter ports, while the third port provides the power balance in the system. The averaged model includes both the DC response of the circuit and the AC response. The DC response of the circuit during DCM is also considered. Simulated and experimental results are presented that validate the accuracy of the model. This model can be used in the future to design the feedback regulation loops needed to control the circuit

Carbon nanostructure based functional hybrid molecules hold promise in solarenergy harvesting. Research presented in this dissertation systematically investigates building of various donor-acceptor nanohybrid systems utilizing enriched single walled carbon nanotube and graphene with redox and photoactive molecules such as fullerene, porphyrin, and phthalocyanine. Design, synthesis, and characterization of the donor-acceptor hybrid systems have been carefully performed via supramolecular binding strategies. Various spectroscopic studies have provided ample information in terms of establishment of the formation of donor-acceptor hybrids and their extent of interaction in solution and eventual rate of photoinduced electron and/or energy transfer. Electrochemical studies enabled construction of energy level diagram revealing energetic details of the possible different photochemical events supported by computational studies carried out to establish the HOMO-LUMO levels in the donor acceptor systems. Transient absorption studies confirmed formation of charge separated species in the donor-acceptor systems which have been supported by electron mediation experiments. Based on the photoelectrochemical studies, IPCE of 8% was reported for enriched SWCNT(7,6)-ZnP donor-acceptor systems. In summary, the present investigation on the various nanocarbon sensitized donor-acceptor hybrids substantiates tremendous prospect, that could very well become the next generation of materials in building efficient solar energy harvesting devices andphotocatalyst.

With improvements of thermoelectric materials leading to higher figures of merit, interest has been developed in a broad spectrum of applications. In this study, the thermal performance of a solar-driven thermoelectric (TE) generator was examined by computer simulation and analytical formulations. The hot junction of the disk-shaped TE module is heated by a conical-shaped solar concentrator reflecting rays onto a cylindrical inner electrode. Controllable cooling water flow cools the outer P ΓÇô N junctions to establish the necessary thermal potential for electric generation. Desired power output can be obtained from a number of TE modules in series and parallel. The computer program was used to examine periodic constant flow rate of the cooling water. It was found that the constant flow rate operation yielded the highest time-integrated TE thermal efficiency. Other parametrical studies performed include the height of copper rod, the ratio of outer to inner diameters of the disks, the thickness of the disks, the solar influx and the heat transfer coefficient between cooling water and the modules. The computer and analytic results on these studies show similar behaviors. It was found that the efficiency of the solar thermoelectric cogenerator ranges from 1.5 to 5.0 percent which is considerably lower than a photovoltaic system.

This thesis describes the design, construction, and evaluation of a series of LED array photolysis systems for high throughput photochemistry. Three generations of array systems of increasing sophistication are evaluated using calorimetric measurements and potassium tris(oxalato)ferrate(III) chemical actinometry. The results are analyzed using descriptive statistics and analysis of variance (ANOVA). The LEDs in the third generation array were shown to be statistically equivalent, with respect to light output, according to physical and chemical actinometry experiments. The third generation LED array was compared with a traditional 1000 W Xe arc lamp source in terms of cost, light intensity, and light stability. Two constant current drivers were evaluated with respect to LED array performance. The optimized third generation LED array was evaluated as the photolysis source for photochemical hydrogen production experiments using the supramolecular catalyst [{(bpy)2Ru(dpp)}2RhCl2](PF6)5. / Master of Science

Several techniques have been proposed for storing collected solar energy. A study was undertaken to investigate energy losses to the soil surrounding a below grade solar energy storage pond. A three dimensional finite element model was developed to approximate the solution of the differential equation of heat transfer. The Crank-Nicholson central difference scheme was used to solve for the time derivative. Four small ponds were constructed at the VPI & SU Swine Center, Blacksburg, Virginia, to study the effect of insulation on heat losses from a warmed water pond. The water in each pond was warmed with an electric resistance immersion heater. The power consumed by each heater was metered. The uninsulated (control) pond was more thoroughly instrumented with thermocouples than were the other three ponds. These thermocouples provided data that were used as input to the computer model as well as data to verify the model. Based on the conditions under which the model was tested, energy losses to the soil from an uninsulated pond were on the order of 26.H-31-7 MJ/day (25-30 k BTU/day). By providing insulation to the ground surface and to a depth of 0.66 m (2 ft) at a distance of 0.33 m (1 ft) from the pond edge, energy loss to the soil was reduced to about 33 percent of the uninsulated case. Insulation of the pond sides and bottom resulted in energy losses that were about 16 percent of those for the uninsulated pond. / Ph. D.

Orientadores: Carla Kazue Nakao Cavaliero, Ennio Peres da Silva / Tese (doutorado) -Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-12T18:30:16Z (GMT). No. of bitstreams: 1 Varella_FabianaKarladeOliveiraMartins_D.pdf: 2814812 bytes, checksum: 2b3d8b0306df42b90c009281f0150f0d (MD5) Previous issue date: 2009 / Resumo: A Lei nº 10.438/02 estabeleceu o Programa de Incentivo às Fontes Alternativas de Energia Elétrica - PROINFA, único programa nacional a estimular as fontes renováveis alternativas, com o intuito de aumentar a participação da energia elétrica produzida por empreendimentos a partir das fontes eólica, pequenas centrais hidrelétricas - PCHs e biomassa no sistema interligado nacional. Posteriormente, o PROINFA foi revisado pela Lei nº 10.762/03 e alterou em sua regulamentação a obrigatoriedade de um índice mínimo de nacionalização de serviços e equipamentos, que em sua primeira etapa passou a corresponder a 60% do custo total da construção dos projetos contemplados. A energia solar fotovoltaica não foi contemplada pelo Programa, e o objetivo desta tese é estimar o índice de nacionalização para cada um dos três sistemas fotovoltaicos selecionados para estudo (sistema de bombeamento de água, sistema de eletrificação rural e sistema conectado à rede elétrica). Para elaboração desse cálculo foi efetuada uma adaptação da metodologia utilizada pelo PROINFA e considerados somente os custos dos principais equipamentos e não dos serviços. Os resultados obtidos permitiram concluir que os sistemas de bombeamento de água e de eletrificação rural são sistemas que 5% e 35%, respectivamente, dos seus equipamentos já são disponibilizados pela indústria nacional. mesmo não ocorre com os sistemas fotovoltaicos conectados à rede elétrica, que atualmente tem 100% dos seus principais equipamentos importados / Abstract: The Law nº 10.438/02 established the Program of Incentives for Alternative Electric Power Sources - PROINFA, which is the only national program aimed to foster alternative renewable energy sources and to increase the share of electric energy production from enterprises based on wind power, small hydropower plants and biomass in the interconnected national power grid. PROINFA was later modified by the Law nº 10.762/03 which revised the regulation imposing a minimum nationalization index of services and equipment that in its first stage corresponded to 60% of the total cost of the selected projects. Solar photovoltaic power was not included in PROINFA and because of that the objective of this thesis is to estimate the nationalization index of each of the following photovoltaic systems selected for the study: water pumping PV system, rural electrification PV system and grid-connected PV system. In order to carry out the calculations, the methodology used at PROINFA was adapted and only the costs of the key equipment, not the services, were considered. The results led to the conclusion that the water pumping and the rural electrification systems are those in which 5% and 35%, respectively, equipment is already made available by the national industry. The same is not verified for the grid-connected PV systems in which 100% of the key equipment is imported / Doutorado / Doutor em Planejamento de Sistemas Energéticos

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