FIFTH SYMPOSIUM

5th Int’l Symposium on Energy; February 6 – 8, 2013

Energy Harvesting: Power at Small Scale
Edwar Romero
Universidad del Turabo, Gurabo, Puerto Rico

Energy harvesting is a new promising research area for portable electronics. Portable electronic devices have been typically limited by the finite lifetime and size of the internal batteries. This has been a constant conflict and tradeoff between battery size and device capabilities. For instance, cardiac pacemaker lifespan is mostly limited by battery size, which occupies at least half the available volume. Energy harvesting or energy scavenging is an alternative that extracts energy from the surroundings in order to operate. Energy harvesting is also an interesting approach when battery replacement is not possible or is too costly, such as deployment of sensors in remote areas for surveillance or environmental monitoring. One of the best known examples is the self-winding wristwatch that started from being completely mechanical and operated by the wearer’s daily motion, to be nowadays a miniaturized electrical generator. Energy harvesting extracts energy from the surrounding by harnessing motion, vibrations, and temperature gradients among others. Kinetic energy generators extract energy by means of piezoelectric, electromagnetic, or electrostatic transduction techniques. Piezoelectricity is produced by materials with piezoelectric properties when subject to pressure, generating a voltage as a result. Electromagnetic transduction uses the relative motion of magnets and coils in order to induce a voltage. Electrostatic generators use the change of capacitance, by varying the separation between plates, to generate an electrical charge. Applications of the technology vary from consumer electronics, remote deployment of sensors to biomedical applications. This work presents the state-of-the-art on energy harvesting applications.

Iluminación Residencial Rural Mediante el uso de Bombillas LED y Energía Solar
Robinson Jiménez; Andres Jutinico
Universidad Antonio Nariño, Bogotá, Colombia

Nowadays, LED bulbs are an efficient lighting source, with low energy consumption and with a luminous power equivalent to the existing tungsten filament bulbs. The above, plus its operation with DC voltage, becomes an important advantage in systems that use these bulbs and solar panels as energy supply devices. The present paper presents the design, implementation and analysis of a residential illumination system in an isolated rural zone; this system its composed by solar panels as energy acquisition device, LED bulbs as illumination devices and a rack of batteries as energy storage device, which are in charge of the nightly energy supply.

Design and Control of Standalone P-V System for Rural Residential Applications
Ahmed Ghareeb; Tarek A. Youssef; Ahmed Mohamed; Osama A. Mohammed
Florida International University, Miami, Florida, USA

In this paper, the design of a standalone P-V system in terms of sizing of P-V units and battery storage will be discussed. The sizing of the system will be determinant based on the expected loads, characteristics of the used PV module and the meteorological data of the region of installation. The system consists of PV panels, a DC-DC converter interfacing PV panels, a bi-directional DC-DC battery charger and a single phase inverter interfacing the DC bus to the loads. The power conditioning unit needed to regulate the output voltage of the system across the terminals of the load and track the maximum power point (MPP) will be presented. The control of power electronic converter will be developed and investigated. An economic evaluation will be done to validate the applicability of the designed system.

Power Generation Using Diesel and Biogas  as Fuels for Agricultural Applications
Alvaro Fiorella; Herbert Jesús Del Carpio Beltrán; Juan José Milón Guzmán; Sergio Leal Braga
Pontifical Catholic University of Rio de Janeiro, Río de Janeiro, Brazil

In recent years, the technology of anaerobic digestion has been widely adopted by Peruvian agricultural industries for the processing of their organic residues, having as the main aim the obtainment of high quality bio-fertilizers; nevertheless, biogas was also produced in the process. Since this biofuel was not used in any process, it was burnt in torches or freed directly from the digester, polluting the environment in both ways. In this context, an experimental device was designed and built to evaluate the performance of a 36 kW Diesel cycle generator using diesel and biogas as fuels for electricity generation. A diesel-biogas conversion kit was installed in the generator set to allow the variation of the Duty Cycle, a varying parameter that controls the percentage of time the biogas injectors are opened, modifying, this way, the diesel substitution rate. The performance of the unit was evaluated at different electrical charges (from 5 to 30 kW) and different diesel substitution rates (from 0 to 75%). The biogas used for the tests contained 50% of methane. During the operation with biogas, the power output kept constant due to the diesel-biogas conversion kit control. The maximum substitution rate attained was 73% at 30 kW. The specific diesel consumption was reduced to 190 g/kWh at high loads. The results indicated that for higher Duty Cycles (higher quantities of biogas), the exhaust temperatures increased, due to the superior temperature of biogas combustion. The use of biogas for substitution of diesel for power generation shows itself as an opportunity for an appropriate management of energy resources, which could benefit the operation of enterprises located far from the city with energy supply problems, allowing the use of biogas commonly produced in the same place with the organic residues they manage for useful purposes, diminishing pollution and reducing costs.

Diseño del Control Digital de un Seguidor Solar para la Medición de Radiación Solar Directa en Bogotá
Andrés Jutinico
Universidad Distrital Francisco José de Caldas, Bogotá, Colombia

La radiación solar directa es una variable, que no es comúnmente medida en la ciudad de Bogotá y que es de gran interés en diseño de sistemas Foto Voltaicos. El presente artículo describe el diseño de un controlador digital, implementado en un seguidor solar acoplado a un Pirheliómetro, con el fin de realizar dicha medición. Los índices de desempeño del sistema son adecuados para el seguimiento solar, en particular se elimina el error de estado estacionario utilizando un compensador dither y el tiempo de estado estacionario es de 28 segundos. El controlador y el sensor se encuentran en funcionamiento desde el 17 de julio de 2012 de forma continua, esto contribuirá a complementar los estudios realizados al medio ambiente en la ciudad. El documento está divido en cinco secciones las cuales muestran la identificación del modelo de referencia del seguidor solar, el diseño del controlador utilizando un modelo de referencia y el controlador en LabVIEW.

Portable Green Unit: Harvesting Rain Energy
Andrés Tremante, Javier Palencia, Alberto Hernández
Florida International University, Miami, FL, USA

We propose two rainwater electric system concepts that use a small hydro turbine to generate electrical power to supplement other more common sources of renewable energy such as solar and wind. The first concept is designed for high precipitation density locations and consists in attaching a turbine assembly unit to a building’s existing gutter/ drainage system. The second concept stores the run-off rain water in a tank before passing through a turbine, making this design less dependent on precipitation density and able to generate a more stable power output. Both can be adapted to most homes or building gutter/drainage systems, and can serve as a low cost means of harnessing the natural energy produced by falling rainwater. We also describe the Green Energy Unit which is an off-grid portable and self-contained renewable energy system that is being developed at FIU for providing aid in emergency situations, such as disaster response, and remote locations where there is no access to shore line power. The rainwater system will be implemented as part of the Green Energy Unit, expanding its capability to provide electrical power in most climates, maximizing the use of each energy source while minimizing the need to run fossil fuel generators.

Characterization of Water Absorption and Desorption Properties of Natural Zeolites in Ecuador
Armando Adriano, Guillermo Soriano, Jorge Duque,
Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador

The feasibility of using natural zeolites from Policia deposit located at Chongon – Colonche mountain range in the ecuadorian coast as dessicant material is evaluated. Samples were collected and mineralogically characterized using X-ray Diffraction, Fourier Transform Infrared spectroscopy. It was found that samples consisted mainly of mordenite and clinoptilolite. A dissicant filter was built using samples reduced to three different sizes: Type I (250-150μm), II (150-45 μm) y III (<45μm). The filter was mounted on a wind tunnel and tests to measure difussion velocity of water were performed where the type III samples outperformed the other types. Desorption tests were performed using X-ray Diffraction, Fourier Transform Infrared spectroscopy with the samples subject to heating cycles at 60°C for 24 and 48 hours. Desorption tests showed small losses in the water content with possible changes in the porosity of the samples.

Arquitectura de Bajo Consumo: Modelos de Reducción Energética a través del Diseño
Emmanuel Ramírez, Wilfredo Méndez,
AIA, AIT, San Juan, Puerto Rico

Constantemente se presenta en la industria de la construcción el tema ecológico como la estrategia que mejorará el negocio. Presentar equipos que puedan reducir el consumo energético se interpreta como el valor añadido que debemos aspirar. La aplicación de productos “verdes” sin tener un modelo de negocio y una estrategia de diseño consistente con las iniciativas ecológicas, puede llegar a afectar el costo- efectividad de la obra. En nuestros tiempos, el edificio en ocasiones resulta ser más caro, más si sumamos el uso de iluminación y aire acondicionado adicional por no optimizar previamente su diseño, dará la estocada final, que es pretender amortiguar el consumo con sistemas sustentables. Debemos alejarnos de la pre-concepción de “la ecología” como la adquisición de productos “verdes”. Los profesionales de la industria deben comenzar a trabajar de forma integrada. ¿Qué les parece si la investigación logra optimizar el uso de sus materiales y a través de la integración pericial lográramos la reducción de energía de hasta un 35% sin añadir un sistema solar o de viento? Esta reducción equivale al 20% en ahorros en comparación con el costo total y reduciría la huella de monóxido de carbono hasta 3 toneladas. Presentaremos 3 ejemplos que cambiarán el concepto de construcción ecológica. Primero presentamos una cancha capaz de funcionar con cero consumo de energía y a un costo menor a la cancha convencional. Segundo, presentaremos un diseño de hospital capaz de reducir el consumo de energía y de utilidades basándose en el concepto de biomimesis. Por último, demostraremos estudios científicos que demuestran como a través del estudio de la naturaleza se puede lograr construcciones eficientes y energéticamente autosuficientes. El discurso ecológico suena bien, pero si no innovamos las estrategias de diseño y el modelo de negocio para una construcción sustentable,

Induced Air Flow Through a Vertical Pipe Heated by Radiation Effects
Gerardo Carbajal; Luis R. Rivera Santiago; Félix O. Cotto Flores
Universidad del Turabo, Gurabo, Puerto Rico

An experimental study of radiation effects on induced air flow through a vertical pipe is presented. To simulate the radiation effects, four bulbs of 120W each one, with a total power of 480W, were used in the experiments. Special concave plates were specially designed and built to receive the maximum radiation. An appropriate expression for the shape factor was applied. All the surfaces exposed to the direct radiation heat transfer were black painted. Different radiative power were tested in order to determine the minimum conditions for induced air flow. It was found that it was possible to generate a steady air flow inside the pipe. A radiative power of 240 W applied to a 11.4 cm inside pipe diameter produced and air flow with an average velocity of 0.1667 m/s.

Two Phase Flows with Magnetic Nanofluids in a Presence of a Magnetic Field
Gerardo Carbajal; Edwar Romero
Universidad del Turabo, Gurabo, Puerto Rico

The effect of air bubbles in 70 % isopropyl alcohol with magnetic nanoparticles (Fe3O4) in both the absence and presence of a magnetic field was studied. In this study, the magnetic nanofluids in isopropyl alcohol was found to counteract the buoyancy force of bubbles in the absence of the magnetic field. The air bubbles were generated by an air pump, that allow to study the behavior of the bubble rise with magnetic nanofluids in presence of a magnetic field. The air bubbles stay suspended much longer in presence of a magnetic field than in absence of a magnetic field. In presence of a magnetic field, the average size of the departing bubbles decreased and the bubble frequency increased by 19 percent compared with the bubble flow with nanofluids in the absence of a magnetic field. Additionally, it was observed that the magnetic field affected the air bubble velocity in the bulk fluid.

Biomass Ethanol Production for Flex Fuel Vehicles: The BBFuels of Puerto Rico Business Project
Johnny Lugo Vega, Jorge Nina
BBFuels of Puerto Rico,LLC, Carolina, Puerto Rico

BBFuels de Puerto Rico, LLC is a green company that proposes a novel approach to biomass conversion to energy that reduces the overall process complexity required to produce ethanol by means of wet water hyacinth of Puerto Rico (Eichhornia crassipes). The problems that this project solves are the lack of E85 supply for FFV owners, and the overpopulation of hyacinths. Due to hyacinths high lignocelluloses content they can be considered a promising substrate for the production of bioethanol. For that reason, the development of ethanol from water hyacinth of Puerto Rico is the innovation offered by this proposal. Water Hyacinth has an extremely rapid growth rate that clogs rivers and prevents navigation due to a perfect environment: the tropics. It could be useful as a source of biomass because of its abundance and feasible cultivation. The impact that this innovation could have over society consists of improving the quality of life and the environment while providing an alternative fuel that is less pollutant at a lower cost than fossil fuels. This innovation would provide E85 ethanol for flex fuel vehicles being acquired despite the lack of E85 in the Puerto Rican market. In addition, production of ethanol 100 will satisfy other unattended markets such as Universities, Hospitals or local and federal emergency agencies. The bioethanol from water hyacinth and anaerobic bacteria has a significant reduction in the cost per gallon of ethanol, (estimated 64%) due to use of wet biomass instead of typical dry biomass from water hyacinths. The production of ethanol in Puerto Rico will provide a real option to FFV owners and has a potential commercial value since the amount of such vehicles being produced and acquired is increasing as a result of federal and local incentives.

Producción de biodiesel a Partir de Aceite de Palma de Moriche Mauritia Flexuosa Lf., en la Altillanura Colombiana
Marco Aurelio Torres Mora
Universidad de los Llanos, Villavicencio, Meta, Colombia

Los biocombustibles se han venido implementando en el mundo como alternativa energética a los combustibles de origen fósil; con este propósito en la altillanura colombiana se han venido establecido grandes cultivos de palma de aceite para la producción de biodiesel y de caña de azúcar para alcohol, entre otros. En este estudio se planteó como objetivo el uso de aceite de palma de moriche, Mauritia flexuosa L.f., especie que forma grandes asociaciones en terrenos mal drenados conocidos como morichales, presentes únicamente en la orinoquia y amazonía, como fuente de materia prima para producción de biocarburante. La metodología consistió en caracterizar físico-químicamente el aceite y el biodiesel obtenido, y compararlos con los obtenidos a partir de aceites vegetales de la palma de aceite Elais guineensis jacq, de la palma de seje Oenocarpus bataua Mart, y de la colza Brassica napus L. En los resultados se encontró que la densidad del metiléster del aceite de moriche, de seje y de la palma de aceite son similares a la del diesel; en la temperatura obtenida del cloud point, para el moriche fue de 4ºC, resultado que favorece su uso, dado que en la región no se alcanzan esas temperaturas. Finalmente se concluyó que el moriche como ecosistema estratégico puede satisfacer necesidades básicas en la producción de energía y en el uso sostenible de recursos de la biodiversidad local.

Evaluación del Impacto de la Electrificación Rural Sobre El Bienestar de los Hogares en el Perú
Max Arturo Carbajal Navarro, Erix Aldo Ruiz Mondaca
Universidad Nacional Mayor de San Marcos, Lima, Perú
Organismo Supervisor de la Inversión en Energía y Minería (OSINERGMIN), Lima, Perú

Los biocombustibles se han venido implementando en el mundo como alternativa energética a los combustibles de origen fósil; con este propósito en la altillanura colombiana se han venido establecido grandes cultivos de palma de aceite para la producción de biodiesel y de caña de azúcar para alcohol, entre otros. En este estudio se planteó como objetivo el uso de aceite de palma de moriche, Mauritia flexuosa L.f., especie que forma grandes asociaciones en terrenos mal drenados conocidos como morichales, presentes únicamente en la orinoquia y amazonía, como fuente de materia prima para producción de biocarburante. La metodología consistió en caracterizar físico-químicamente el aceite y el biodiesel obtenido, y compararlos con los obtenidos a partir de aceites vegetales de la palma de aceite Elais guineensis jacq, de la palma de seje Oenocarpus bataua Mart, y de la colza Brassica napus L. En los resultados se encontró que la densidad del metiléster del aceite de moriche, de seje y de la palma de aceite son similares a la del diesel; en la temperatura obtenida del cloud point, para el moriche fue de 4ºC, resultado que favorece su uso, dado que en la región no se alcanzan esas temperaturas. Finalmente se concluyó que el moriche como ecosistema estratégico puede satisfacer necesidades básicas en la producción de energía y en el uso sostenible de recursos de la biodiversidad local.

Efficient Heat Transfer Teaching in Engineering Energy Problems
Roberto C. Callarotti;
Universidad del Turabo, Gurabo, Puerto Rico

In this paper we discuss the application of the proper eigenvalue method (PEM) developed by the author to time dependent problems in heat transfer not involving the changes of phase of the system components.
The method is based on the solution of the generalized eigenvalue problem, where the eigenvalues are identified as poles and zeros. This process allows a trivial determination of the inverse Laplace transforms involved Iteration in time is avoided (thus avoiding possible instabilities in systems with more than one space dimension), achieving a reduction of several orders of magnitude in the required computer time. The method can also be applied to linear problems in electrochemistry, fluid flow in porous media, electromagnetic theory, and fluid mechanics.

Fossil Fuels and Energy Sustainability
Roberto C. Callarotti;
Universidad del Turabo, Gurabo, Puerto Rico

In this paper we discuss the concept of net energy efficiency (Energy Return On energy Invested EROI) in general. We discuss the reality of world energy resources of oil, shale oil, gas, shale gas, and coal. For some of them (oil, gas and coal) we estimate the future of their production in tem of logistic models. We analyze the current production of shale gas.
We present detailed results for the EROI associated with heavy oil production. For steam injection the EROI is found to be in the range of 10 to 50. For electrical heating, reported field data falls in the same range when the applied energy is taken to be the maximum energy of the heaters.
We discuss the EROI for the production of methane from submarine hydrate deposits by 60Hz electrical heating (EROI = 1.7) and the EROI for or the case of thermal excitation in accordance to the Japanese scheme for the Nankay trough – EROI above 30 when the production starts, decreasing to a value of 7 after 30 years.

Biomass Briquettes: A Sustainable and Environment Friendly Energy Option for the Caribbean
Sastry Musti K.S. , Jacqueline Bridge; Alvin Brown3, Renee Williams
University of the West Indies, St Augustine Campus, Trinidad and Tobago

Since the beginning of the 21st century the cost of energy has been a significant percentage of countries’ production cost. For most countries their main source of energy has been fossil fuels. The use of fossil fuels is not sustainable as this is a non renewable source of energy. This paper outlines the adoption experiences of biobriquetting industry across the globe and current experimental investigations carried out by us. It then goes into detail about a relatively untapped option in the Caribbean – biomass briquettes, specifically countries like Jamaica where the energy import bills are very high. Biomass briquettes have been successfully used as alternative form of fuel in a number of countries. The overall bio-briquetting process from production to end-use offers solution to the disposal of harmful waste, results in a cheaper form of energy, creates new employment/ business opportunities and is very eco-friendly.

Electrical Energy from Fluttering Membranes
Visvanatha Sundararajan; Edwar Romero; Pablo J. Pérez Pereira Jorge Jiménez Polanco Luis Vilar Carrasquillo
Universidad del Turabo, Gurabo, Puerto Rico

Vibration energy harvesting using piezoelectric generators have been preferred due to the higher power output. Such low power generated can be successfully used to power wireless sensors nodes while extracting energy from environmental sources. Machine vibrations have been typically chosen for this endeavor, but recently fluid flow energy harvesting induced are being investigated. This research focuses on study of the self-sustained oscillations (panel flutter) for energy generation with the use of flexible piezoelectric materials (MFC) with a thickness of 9 μm attached to a thin Mylar. Wind speeds a low as 7 mph can produce an open-circuit of 0.85 volt.