Research Papers/Topics in Electrical Engineering

SQUARE WAVE TO SINOUNSIDAL WAVE FORM

The availability and stability of electrical energy is necessary for domestic and industrial use. But unfortunately the monopoly which the Power holding company of Nigeria (PHCN) enjoys in this country is not in favor of the electricity users, because the supply is never constant and damages occur due to inconsistency of this supply is very enormous. However, millions of naira’s are lost every day in the commercial and industrial sectors, and even at the same time a lot of Lives are wasted ...

Microstructurally Engineered p-layers for Obtaining High Open-Circuit Voltages in a-Si:H n-i-p Solar Cells

A study was carded out with the goal of obtaining high open circuit voltages (Voc) in a-Si:H n-i-p solar cells, taking into account the evolutionary nature of the microstructure of the p-layers during growth. It is found that cells with players in the protocrystalline Si:H growth regime give the highest values of Voc not those with microcrystalline Si:H p-layers. Evidence for this conclusion is presented whereby Voc is related directly to the microstructure of the p-layers, as characterized u...

Maximization of the open circuit voltage for a-Si:H n-i-p solar cells by incorporation of protocrystalline Si:H p-type layers

In studies of hydrogenated amorphous silicon (a-Si:H) n–i–p solar cells fabricated by rf plasma-enhanced chemical vapor deposition (PECVD), we have found that the maximum open circuit voltage (Voc) is obtained by incorporating p-type doped Si:H layers that are protocrystalline in nature. Specifically, these optimum p layers are prepared by PECVD in the a-Si:H growth regime using the maximum hydrogen-to-silane flow ratio possible without crossing the thickness-dependent transition into the...

Correlation of Light-Induced Changes in a-Si:H Films with Characteristics of Corresponding Solar Cells

For the first time direct correlations are obtained between the light induced changes under 1 sun illumination in the properties of a-Si:H and those in the characteristics of p-i-n cells incorporating identically-prepared i-layers. These correlations were obtained after account was taken of the effects that the location of the electron and hole quasi-Fermi levels have on the carrier recombination that occurs through the different gap states. The changes in midgap state density, as measured on...

Photovoltaics — a path to sustainable futures

As both population and energy use per capita increase, modern society is approaching physical limits to its continued fossil fuel consumption. The immediate limits are set by the planet’s ability to adapt to a changing atmospheric chemical composition, not the availability of resources. In order for a future society to be sustainable while operating at or above our current standard of living a shift away from carbon based energy sources must occur. An overview of the current state of active...

Absence of carrier recombination associated with the defect pool model in a-Si:H i-layers: Evidence from current-voltage characteristics on p-i-n and n-i-p solar cells

Forward bias current–voltage characteristics (JD–V) were studied for both p–i–n (superstrate) and n–i–p (substrate) (a-SiC:H p)/(a-Si:H i) solar-cell structures having different p/i interface layers and different thickness i-layers. Contributions of the p/i interfaces to the JD–V characteristics were separated, and the dependence on the thickness of the i-layers was established. Equivalence was observed in a comparison of the characteristics of p–i–n and n–i–p cells....

Light Induced Defect States in Hydrogenated Amorphous Silicon Centered Around 1.05 and 1.2eV from the Conduction Band Edge

To take into account the presence of multiple light-induced defect states in hydrogenated amorphous silicon (a-Si:H) the evolution of the entire spectra of photoconductive subgap absorption, α(hν), has been analyzed. Using this approach two distinctly different light-induced defect states centered around 1.0 and 1.2 eV from the conduction band edge are clearly identified. Results are presented on their evolution and respective effects on carrier recombination that clearly point to the impor...

Numerical Simulation of the Direct Application of Compound Parabolic Concentrators to a Single Effect Basin Solar Still

As regional shortages of fresh water become more prevalent, solar distillation using a single-effect basin holds promise as a method to bring low-cost, clean, and ecologically-responsible water to remote area dwellers. Compound parabolic concentrators (CPCs) can be used to direct more light onto the still increasing the throughput and efficiency of these passive solar devices. A computer program has been developed that uses the properties of materials and the solar energy characteristics of t...

3D-mapping optimization of embodied energy of transportation

Resources Conservation and Recycling, Jan 1, 2007The recent development of Google Earth, an information service that provides imagery and three dimensional data depicting the entire Earth, provides an opportunity to use a new method of navigating information to save energy in the real world. Google Earth uses Keyhole Markup Language (KML) for modeling and storing geographic features and information for display in the Google Earth Client. This paper will analyze the potential of this novel and...

Reducing greenhouse gas emissions by inducing energy conservation and distributed generation from elimination of electric utility customer charges

This paper quantifies the increased green house gas emissions and negative effect on energy conservation (or “efficiency penalty”) due to electric rate structures that employ an unavoidable customer charge. First the extent of customer charges was determined from a nationwide survey of U.S. electric tariffs. To eliminate the customer charge nationally while maintaining a fixed sum for electric companies for a given amount of electricity, an increase of 7.12% in the residential electrical ...

Increasing PV Velocity by Reinvesting the Nuclear Energy Insurance Subsidy into Large Scale Solar Photovoltaic Production

As the debate over the future of energy grows, often nuclear energy production is pitted against solar photovoltaic energy conversion. There is a widespread belief that solar cannot compete with nuclear energy economically without government subsidies. The continued and widespread belief in the economic viability of nuclear energy, however, is predicated in part on government-mandated limitation on the liability of the nuclear industry. To demonstrate the magnitude of this nuclear energy insu...

Expanded microchannel heat exchanger: design, fabrication and preliminary experimental test

This paper first reviews non-traditional heat exchanger geometry, laser welding, practical issues with microchannel heat exchangers, and high effectiveness heat exchangers. Existing microchannel heat exchangers have low material costs, but high manufacturing costs. This paper presents a new expanded microchannel heat exchanger design and accompanying continuous manufacturing technique for potential low-cost production. Polymer heat exchangers have the potential for high effectiveness. The pap...

Open-Source Colorimeter

The high cost of what have historically been sophisticated research-related sensors and tools has limited their adoption to a relatively small group of well-funded researchers. This paper provides a methodology for applying an open-source approach to design and development of a colorimeter. A 3-D printable, open-source colorimeter utilizing only open-source hardware and software solutions and readily available discrete components is discussed and its performance compared to a commercial porta...

Optimizing limited solar roof access by exergy analysis of solar thermal, photovoltaic, and hybrid photovoltaic thermal systems

An exergy analysis was performed to compare a conventional (1) two panel photovoltaic solar thermal hybrid (PVT x2) system, (2) side by side photovoltaic and solar thermal (PV + T) system, (3) two module photovoltaic (PV) system and (4) a two panel solar thermal (T x2) system with identical absorber areas to determine the superior technical solar energy systems for applications with a limited roof area. Three locations, Detroit, Denver and Phoenix, were simulated due to their differences in a...

Effects of spectral albedo on solar photovoltaic devices

Although the spectral effects of direct and diffuse radiation on solar photovoltaic (PV) performance are relatively well understood, recent investigations have shown that there can be a spectral bias introduced due to albedo from common ground surfaces that can impact the optimal selection of PV materials for a known location. This paper extends analysis to the effects of spectral bias due to the specular reflectivity of 22 commonly occurring surface materials (both man-made and natural) and ...


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