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NARROW
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1-18 of 18
Juan C. Ordóñez
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Journal Articles
Accepted Manuscript
Article Type: Research Papers
J. Thermal Sci. Eng. Appl.
Paper No: TSEA-20-1744
Published Online: April 2, 2021
Abstract
In this work, a thermodynamic model based on endoreversible engine approach is developed to analyze the performance of heat engines operating under different thermodynamic cycles. The model considers finite heat transfer rate, variable heat source and sink temperatures, and irreversibilities associated with the expansion and compression. Expressions for the maximum power and efficiency at maximum power output are obtained as a function of hot and cold reservoir temperatures, the equivalent isentropic efficiency of compression and expansion components, and the effective conductance ratio between heat exchangers. In all cases, the Curzon-Ahlborn efficiency is retrieved at constant reservoir temperatures and neglected compression-expansion irreversibilities. The proposed model allows assessing the effect of isentropic efficiencies and heat exchanger design and operation characteristics for different thermodynamic cycles.
Proceedings Papers
Gleidson Souza, José V. C. Vargas, Wellington Balmant, Marcos C. Campos, Leonardo C. Martinez, Juan C. Ordóñez, André B. Mariano
Proc. ASME. HT2019, ASME 2019 Heat Transfer Summer Conference, V001T07A007, July 14–17, 2019
Paper No: HT2019-3708
Abstract
Current refrigeration and air conditioning systems are mostly based on the vapor compression cycle, which require electrical energy input. Absorption systems have gained new interest due to the possibility of utilizing waste heat as energy input. In addition, the environmental impact generated by such systems is recognized as much smaller than vapor compression systems. Therefore, this work developed and characterized an absorption refrigeration system with an innovative generator level optical control and variable working fluid mass flow rate, with potential for use in industrial, commercial and residential heating, ventilation, air conditioning, and refrigeration (HVAC & R) systems. The system is hybrid, since it was designed to be fed with heat from the burning of different fuels and/or waste heat sources in complementary fashion. The system consists of: a condenser, an evaporator, two expansion valves, two absorbers, a centrifugal pump, a regenerative heat exchanger, a generator, a rectifier, a generator level optical control system, and two liquid accumulators. The developed level control system consists of 3 light Dependent Resistors (LDR) positioned inside a box built around a transparent level meter, and illuminated internally by a low power light bulb. A frequency inverter and a centrifugal pump allow for the working fluid solution inside the generator to be within a safe range for efficient cooling cycle operation. The system measured refrigeration capacity rate was 2.3 TR, which qualifies as a good performance, since the equipment was originally designed for 1 TR.
Proceedings Papers
Marcos P. Rosa, Jose V. C. Vargas, Vanessa M. Kava, Fernando G. Dias, Daiani Savi, Beatriz Santos, Wellington Balmant, Andre B. Mariano, Andre Servienski, Juan C. Ordóñez
Proc. ASME. ES2019, ASME 2019 13th International Conference on Energy Sustainability, V001T11A008, July 14–17, 2019
Paper No: ES2019-3965
Abstract
Microalgae have a high biotechnological potential as a source of biofuels (biodiesel, biohydrogen) and other high-added value products (e.g., pharmaceuticals, proteins, pigments). However, for microalgae cultivation to be economically competitive with other fuel sources, it is necessary to apply the concept of biorefinery. This seems to be the most ambitious strategy to achieve viability. Therefore, the objectives of this study were to isolate and identify the main microalgae line used to produce biofuels at Federal University of Parana, Brazil, using the rDNA sequence and micromorphological analysis, and to evaluate the potential of this lineage in the production of hydrogen and co-products with biological activity. For the purification of the lineage (LGMM0001), an aliquot was seeded into solid CHU culture medium and an isolated colony was selected. The genomic DNA was purified using a commercial kit (Macherey-Nagel, Düren, Germany) for molecular identification, the ITS region (ITS1, 5.8S and ITS2) (Internal Transcribed Spacer) was amplified and sequenced using primers LS266 and V9G. Morphological characterization was performed as described by Hemschemeier et al. [1]. Finally, for biological activity research, secondary metabolites were extracted by fractionation and evaluated against bacteria of clinical interest. Through microscopic analysis, general characteristics shared by the genus Tetradesmus were observed. The plasticity of the morphological characteristics of this genus reinforces the need for further studies to classify correctly the species in this group, using DNA sequencing. ITS sequence analysis of LGMM0001 showed 100% homology with sequences from the Tetradesmus obliquus species, so, the lineage was classified as belonging to this species. The evaluated microalgae strain was able to produce hydrogen, showing positive results for gas formation. Biological activity was observed with the extract obtained from the residual culture carried out with alternative medium used in the photobioreactors (PBR), against the Staphylococcus aureus pathogenic lineage. In conclusion, the microalgae strain used in this work was identified as Tetradesmus obliquus (= Acutodesmus obliquus ), and was able to produce a compound with economic potential in association with the existing biofuel production process.
Proceedings Papers
Proc. ASME. ES2019, ASME 2019 13th International Conference on Energy Sustainability, V001T16A004, July 14–17, 2019
Paper No: ES2019-3961
Abstract
The global energy demand has increased at a very large rate, and in parallel, the Municipal Solid Waste (MSW) has also increased, both posing enormous technological challenges to world sustainable growth. Therefore, in order to contribute with concrete alternatives to face such quest for sustainability, this work presents an analysis of an integrated power plant fired by municipal solid waste that uses a biological filter for the combustion emissions fixation. The facility located in the Sustainable Energy Research & Development Center (NPDEAS) at Federal University of Parana is taken as a case study to analyze the process of technical and economic viability. For that, an exergoeconomic optimization model of the waste-to-energy power plant that generates electricity and produces microalgae biomass is utilized. An incineration furnace, which has a 50 kg/h capacity, heats the flue gas above 900°C and provides energy for a 15 kW water-vapor Rankine cycle. A set of heat exchangers preheats the intake air for combustion and provides warm utility water to other processes in the plant, which assures that the CO 2 rich flue gas can be airlifted to the microalgae cultivation photobioreactors (PBR) at a low temperature, using a 9 m high mass transfer emissions fixation column. Five 12 m 3 tubular photobioreactors are capable of supplying up to 30,000 kg/year of microalgae biomass with southern Brazil solar conditions of 1732 kWh/m 2 per year. The results show that considering the incineration services, the integrated power plant could have a payback period as short as 1.35 years. In conclusion, the system provides a viable way to obtain clean energy by thermally treating MSW, together with microalgae biomass production that could be transformed in a large variety of valuable bioproducts (e.g., nutraceuticals, pharmaceuticals, animal feed, and food supplements).
Journal Articles
Journal:
Journal of Heat Transfer
Article Type: Research-Article
J. Heat Transfer. November 2019, 141(11): 112502.
Paper No: HT-18-1800
Published Online: September 27, 2019
Abstract
We analyzed the optimal cooling channel layouts emerged from minimizing the total entropy generation S T and mean enclosure temperature T ¯ in a hot enclosure subject to natural convection. The conservation of mass, momentum, and energy were solved numerically in two-dimensional (2D) space using the finite element method, and an ant colony optimization algorithm was employed to determine the optimal layouts with respect to the number of cooling channels (N) and Rayleigh number (Ra). The total allocatable cooling channel area was fixed in all cases and thus each channel area decreased with increasing N. Subsequently, we examined the heat transfer and flow characteristics based on temperature field, streamlines, and local Bejan number of each optimum and deduced the following: (1) All optimal channel layouts were symmetric about the vertical enclosure centerline; however, the optima resulting in S T ,min and T ¯ min did not always coincide and depended heavily on the flow configuration dictated by N and Ra; (2) the competing nature between heat transfer and its irreversibility was pronounced at low Ra and N when convection and fluid friction were ineffective; and (3) the first and second law performance improved as N increased in most cases. Furthermore, results verified the global convergence and robustness of the ant colony optimization approach in solving a layout optimization problem with pure natural convection.
Journal Articles
Fernando G. Dias, Jose V. C. Vargas, Sam Yang, Marcos P. Rosa, Beatriz Santos, Vanessa M. Kava, Wellington Balmant, Andre B. Mariano, Juan C. Ordonez
Article Type: Research-Article
J. Verif. Valid. Uncert. June 2019, 4(2): 021002.
Paper No: VVUQ-19-1002
Published Online: September 16, 2019
Abstract
A dynamic physics-based model developed for the prediction of biohydrogen production in a compact tubular photobioreactor (PBR) was calibrated experimentally. The spatial domain in the model was discretized with lumped control volumes and the principles of classical thermodynamics, mass, species, and heat transfer were combined to derive a system of ordinary differential equations, whose solution was the temperature and mass fraction distributions across the entire system. Two microalgae species, namely, Acutodesmus obliquus and Chlamydomonas reinhardtii strain cc125, were cultured in triplicate with different culture media via indirect biophotolysis. Measured biomass and hydrogen concentrations were then used to adjust the specific microalgae growth and hydrogen production rates in the model based on residual sum of squares (RSS) and the direct search method. Despite its simplicity, the presented volume element model was verified to well predict both hydrogen and biomass concentration over time. The microalgae growth rate for each species was determined as 2.16 μ alga,0 s −1 and 0.91 μ alga,0 s −1 for A. obliquus and C. reinhardtii strain cc125, respectively, where μ alga,0 is the specific growth rate of Scenedesmus almeriensis for given temperature and irradiance. The adjusted maximum hydrogen production rates for the local nonmutant A. obliquus and for C. reinhardtii strain cc125 were 1.3 × 10 −7 s −1 and 4.1 × 10 −7 s −1 . Consequently, these hydrogen production rates were 59 times and 19 times smaller, respectively, than that for the mutant C. reinhardtii strain cc849.
Proceedings Papers
Proc. ASME. ES2018, ASME 2018 12th International Conference on Energy Sustainability, V001T07A010, June 24–28, 2018
Paper No: ES2018-7545
Abstract
This work addresses the development and construction of a sustainable alkaline membrane fuel cell (SAMFC). The SAMFC couples an alkaline membrane fuel cell (AMFC) with a hydrogen generation reactor that uses recycled aluminum from soda cans to split the water molecule through the oxidation of aluminum catalyzed by sodium hydroxide. An innovative cellulosic membrane supports the electrolyte, which avoids the undesirable characteristics of liquid electrolytes, and asbestos or ammonia that are substances that have been used to manufacture alkaline electrolyte membranes, which are knowingly toxic and carcinogenic. Aluminum is an inexpensive, abundant element in the earth’s crust and fully recyclable. Oxygen is supplied to the cell with atmospheric air that is pumped through a potassium hydroxide (KOH) aqueous solution in order to fix CO 2 , and in this way avoid potassium carbonate formation in order to keep the cell fully functional. A sustainable alkaline membrane fuel cell (SAMFC) system with one unitary cell, the reactor, and CO 2 purifier was designed and built in the laboratory. The results are presented in polarization and power curves directly measured in the laboratory. Although recycled aluminum was used in the experiments, the results demonstrate that the cell was capable of delivering 0.9 V in open circuit and approximately 0.42 W of maximum power. The main conclusion is that by allowing for in situ sustainable hydrogen production, the SAMFC could eventually become economically competitive with traditional power generation systems.
Proceedings Papers
Proc. ASME. POWER2018, Volume 1: Fuels, Combustion, and Material Handling; Combustion Turbines Combined Cycles; Boilers and Heat Recovery Steam Generators; Virtual Plant and Cyber-Physical Systems; Plant Development and Construction; Renewable Energy Systems, V001T01A013, June 24–28, 2018
Paper No: POWER2018-7497
Abstract
Urban solid waste generation has drastically grown around the world, requiring creative, ecologically correct and sustainable solutions to be developed. This work considers a problem of thermodynamic optimization of extracting the most energy from a stream of hot exhaust produced by urban solid waste incineration, considering a stoichiometric combustion model, when the contact heat transfer area is fixed. For that, a mathematical model is introduced to evaluate the rate of heat generation due to the waste incineration process, and the exergetic (power) rate captured by a heat recovery steam generator (heat exchanger). The numerical results show that when the (cold) receiving stream boils in the counterflow heat exchanger; the thermodynamic optimization consists of locating the optimal capacity rate of the cold current. At the optimum, the cold side of the heat transfer surface is divided into three sections: preheating of liquid, boiling and superheating of steam. Experimental results are in good qualitative and quantitative agreement with the numerically calculated mathematical model results. Microalgae cultivated in large-scale vertical tubular compact photobiorreactors are investigated to treat the emissions produced by the incineration, and to increase the efficiency of the global system via cogeneration of co-products with high aggregated commercial value.
Proceedings Papers
Fernando G. Dias, Jose V. C. Vargas, Sam Yang, Vanessa M. Kava, Wellington Balmant, Andre B. Mariano, Juan C. Ordonez
Proc. ASME. VVS2018, ASME 2018 Verification and Validation Symposium, V001T03A004, May 16–18, 2018
Paper No: VVS2018-9341
Abstract
In this work, a dynamic physics-based model developed for the prediction of biohydrogen production in a compact tubular photobioreactor was calibrated experimentally. The spatial domain in the model was discretized with lumped control volumes, and the principles of classical thermodynamics, mass, species and heat transfer were combined to derive a system of ordinary differential equations whose solution was the temperature and mass fraction distributions across the entire system. Two microalgae species, namely, Acutodesmus obliquus and Chlamydomonas reinhardtii strain ccI25 were cultured in triplicate with different culture media via indirect biophotolysis. Experimental biomass and hydrogen concentrations were then used to adjust the specific microalgae growth and hydrogen production coefficients based on residual sum of squares and the direct search method.
Proceedings Papers
Volume Element Model for Modeling, Simulation, and Optimization of Parabolic Trough Solar Collectors
Proc. ASME. ES2017, ASME 2017 11th International Conference on Energy Sustainability, V001T05A010, June 26–30, 2017
Paper No: ES2017-3597
Abstract
In this paper we present a dynamic three-dimensional volume element model (VEM) of a parabolic trough solar collector (PTC) comprising an outer glass cover, annular space, absorber tube, and heat transfer fluid. The spatial domain in the VEM is discretized with lumped control volumes (i.e., volume elements) in cylindrical coordinates according to the predefined collector geometry; therefore, the spatial dependency of the model is taken into account without the need to solve partial differential equations. The proposed model combines principles of thermodynamics and heat transfer, along with empirical heat transfer correlations, to simplify the modeling and expedite the computations. The resulting system of ordinary differential equations is integrated in time, yielding temperature fields which can be visualized and assessed with scientific visualization tools. In addition to the mathematical formulation, we present the model validation using the experimental data provided in the literature, and conduct two simple case studies to investigate the collector performance as a function of annulus pressure for different gases as well as its dynamic behavior throughout a sunny day. The proposed model also exhibits computational advantages over conventional PTC models-the model has been written in Fortran with parallel computing capabilities. In summary, we elaborate the unique features of the proposed model coupled with enhanced computational characteristics, and demonstrate its suitability for future simulation and optimization of parabolic trough solar collectors.
Journal Articles
Journal:
Journal of Heat Transfer
Article Type: Research-Article
J. Heat Transfer. May 2014, 136(5): 051903.
Paper No: HT-13-1170
Published Online: March 6, 2014
Abstract
A plate fin is an extended surface made from a plate. Classical longitudinal and radial fins are particular cases of plate fins with very simple shapes and no curvature. In this paper, the problem of a flat plate fin of constant thickness, straight base, and symmetrical shape given by a proposed power law is considered. Particular attention is paid to some basic shapes: rectangular, triangular, convex parabolic, concave parabolic, convergent trapezoidal, and divergent trapezoidal. One- and two-dimensional analyses are conducted for every shape and comparison of results is carried through the usage of a proposed shape factor. Beyond shape, temperature fields and performance for the considered plate fins are shown to be dependent on a set of three Biot numbers characterizing the ratio between conduction resistances through every direction and convection resistance at the fin surface. Effectiveness and shape factor are found to be hierarchically organized by an including-figure rule. For the rectangular, zero-tip, and convergent trapezoidal cases, effectiveness is limited by a maximum possible value of Bit-1/2, and two-dimensional effects are very small. For the divergent trapezoidal case instead, effectiveness can be larger than Bit-1/2, and one-dimensional over-estimation of the actual heat transfer can be substantially large.
Journal Articles
Article Type: Research Papers
J. Electrochem. En. Conv. Stor. August 2012, 9(4): 041006.
Published Online: June 15, 2012
Abstract
As fuel cells continue to improve in performance and power densities levels rise, potential applications ensue. System-level performance modeling tools are needed to further the investigation of future applications. One such application is small-scale aircraft propulsion. Both piloted and unmanned fuel cell aircrafts have been successfully demonstrated suggesting the near-term viability of revolutionizing small-scale aviation. Nearly all of the flight demonstrations and modeling efforts are conducted with low temperature fuel cells; however, the solid oxide fuel cell (SOFC) should not be overlooked. Attributing to their durability and popularity in stationary applications, which require continuous operation, SOFCs are attractive options for long endurance flights. This study presents the optimization of an integrated solid oxide fuel cell-fuel processing system model for performance evaluation in aircraft propulsion. System parameters corresponding to maximum steady state thermal efficiencies for various flight phase power levels were obtained through implementation of the particle swarm optimization (PSO) algorithm. Optimal values for fuel utilization, air stoichiometric ratio, air bypass ratio, and burner ratio, a four-dimensional optimization problem, were obtained while constraining the SOFC operating temperature to 650–1000 °C. The PSO swarm size was set to 35 particles, and the number of iterations performed for each case flight power level was set at 40. Results indicate the maximum thermal efficiency of the integrated fuel cell-fuel processing system remains in the range of 44–46% throughout descend, loitering, and cruise conditions. This paper discusses a system-level model of an integrated fuel cell-fuel processing system, and presents a methodology for system optimization through the particle swarm algorithm.
Proceedings Papers
Proc. ASME. FUELCELL2011, ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology, 399-408, August 7–10, 2011
Paper No: FuelCell2011-54505
Abstract
As fuel cells continue to improve in performance and power densities levels rise, potential applications ensue. System-level performance modeling tools are needed to further the investigation of future applications. One such application is small-scale aircraft propulsion. Both piloted and unmanned fuel cell aircrafts have been successfully demonstrated suggesting the near-term viability of revolutionizing small-scale aviation. Nearly all of the flight demonstrations and modeling efforts are conducted with low temperature fuel cells; however, the solid oxide fuel cell (SOFC) should not be overlooked. Attributing to their durability and popularity in stationary applications, which require continuous operation, SOFCs are attractive options for long endurance flights. This study presents the optimization of an integrated solid oxide fuel cell-fuel processing system model for performance evaluation in aircraft propulsion. System parameters corresponding to maximum steady state thermal efficiencies for various flight phase power levels were obtained through implementation of the PSO algorithm (Particle Swarm Optimization). Optimal values for fuel utilization, air stoichiometric ratio, air bypass ratio, and burner ratio, a 4-dimensional optimization problem, were obtained while constraining the SOFC operating temperature to 650–1000 °C. The PSO swarm size was set to 35 particles and the number of iterations performed for each case flight power level was set at 40. Results indicate the maximum thermal efficiency of the integrated fuel cell-fuel processing system remains in the range of 44–46% throughout descend, loitering, and cruise conditions. This paper discusses a system-level model of an integrated fuel cell - fuel processing system, and presents a methodology for system optimization through the particle swarm algorithm.
Proceedings Papers
Proc. ASME. ES2009, ASME 2009 3rd International Conference on Energy Sustainability, Volume 1, 305-314, July 19–23, 2009
Paper No: ES2009-90345
Abstract
In this paper, a simplified and comprehensive PEMFC mathematical model introduced in previous studies is experimentally validated. Numerical results are obtained with the model for an existing set of commercial unit PEM fuel cells. The model accounts for pressure drops in the gas channels, and for temperature gradients with respect to space in the flow direction, and current increase that are investigated by direct infrared imaging, showing that even at low current operation such gradients are present in fuel cell operation, and therefore should be considered by a PEMFC model, since large coolant flow rates are limited due to induced high pressure drops in the cooling channels. The computed polarization and power curves are directly compared to the experimentally measured ones with good qualitative and quantitative agreement. The combination of accuracy and low computational time allow for the future utilization of the model as a reliable tool for PEMFC simulation, control, design and optimization purposes.
Journal Articles
Fuel Cell-Based Powertrain System Modeling and Simulation for Small Aircraft Propulsion Applications
Article Type: Research Papers
J. Electrochem. En. Conv. Stor. November 2009, 6(4): 041012.
Published Online: August 17, 2009
Abstract
A solid oxide fuel cell-based power system is modeled and simulated to investigate both power management and controllability issues experienced while subjecting the system to the typical power requirements of a small aircraft. Initially, the fuel cell stack is assumed to operate along one characteristic I - V curve, thus isolating the power management study to the system’s powertrain components. Electrical converters transfer dc power from the fuel cell to usable ac power for an electric motor-driven propeller. To avoid oversizing, the fuel cell stack is designed to operate near its maximum power limit during aircraft cruising, while a battery is employed as an alternative source to provide additional power beyond the cruising kilowatt requirement (e.g., takeoff or maneuvering).
Proceedings Papers
Proc. ASME. HT-FED2004, Volume 3, 113-120, July 11–15, 2004
Paper No: HT-FED2004-56398
Abstract
In this paper we consider the fundamental problem of maximizing the power extraction from a hot stream when the collecting stream experiences a phase change and there are limits imposed by the materials on the operating temperatures. It constitutes an extension of [4] where it was pointed out the existence of an optimal mass flow rate ratio of the hot stream to the collecting stream. In this work, we study the effects of the restrictions imposed by limiting temperatures on the spatial configuration, power extraction and the optimal matching of the two streams. An optimal hot-stream-to-collecting-stream mass flow rate ratio can be found when the collecting stream experiences a phase change while in contact with the hottest section of the hot stream. Associated to the optimal mass flow rate ratio there is also an optimal heat exchanger area allocation. The effects of several operating parameters on the optimal configuration are documented. This paper constitutes an illustration of how thermodynamic optimization leads to the discovery of system structure (constructal theory [1]).
Proceedings Papers
Proc. ASME. FUELCELL2004, 2nd International Conference on Fuel Cell Science, Engineering and Technology, 67-78, June 14–16, 2004
Paper No: FUELCELL2004-2454
Abstract
The hydrogen economy is a possible alternative to the current oil based global economy. The technology to build and operate fuel cells is well advanced. However, cost is the reason why fuel cells are not being installed wherever there is a need for more power. Therefore, optimization is a natural alternative to reduce cost and make fuel cells increasingly more attractive for power generation. This paper discusses the process of determining the internal geometric configuration of a unit fuel cell for maximum power. The optimization of construction (architecture) starts at the smallest (elemental) fuel cell level. The optimization of system architecture must be subjected to a fixed volume constraint. There are several degrees of freedom in the fuel cell configuration, i.e., the thickness of two gas channels (fuel and oxidant), two diffusion layers and two reaction layers (anode and cathode) and the electrolyte solution space. Research perspectives for fuel cells are presented and discussed.
Proceedings Papers
Constructal Optimization of the Coupling Between a Hot and a Cold Stream for Power and Refrigeration
Proc. ASME. IMECE2004, Advanced Energy Systems, 263-271, November 13–19, 2004
Paper No: IMECE2004-62102
Abstract
The first part of this paper reviews some basic results regarding the extraction of power from a hot stream. The second part of the paper outlines the thermodynamic optimization of the coupling between a hot and a cold stream for refrigeration under a total heat transfer area constraint, via constructal theory. The refrigeration system is driven by a hot stream of single-phase fluid that is subsequently discharged into the ambient. The irreversibility is due to three heat exchangers and the discharging of the used stream. It is shown that the thermodynamic optimum is pinpointed by an optimal ratio between the mass flow rates of the hot stream and the stream that is heated by the hot stream, and by an optimal distribution of the heat exchanger area inventory among the three heat exchangers of the installation. The robustness of the optima found is investigated regarding to the variation of the design and operating parameters. The connection between constructal theory and the thermodynamic optimization employed in this paper is the end product: the optimal matching of the streams. It represents configuration (architecture, geometry) derived from principle. If design is approached in this manner (constructal theory), design becomes science, not art.