bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal Design and Operation of a Hybrid Gas/Electric Chilled Water Plant
Authors: Ellis Michael W. , Permana Adhi , Ellis Kimberly P. 
Published: November 2021

Abstract
Large commercial buildings and many industrial facilities use central chilled water plants to provide chilled water for air conditioning and process cooling requirements. Equipment for producing chilled water can be driven by electric motors, natural gas fueled engines, or by thermal energy through absorption cooling cycles. The chilled water plant equipment is expensive and pricing structures for electricity, natural gas, and thermal energy are often complex. In order to minimize the cost associated with owning and operating a central chilled water facility, the design approach and operating strategy must consider equipment cost, cooling requirements for the facility, utility cost structures, and equipment performance characteristics.
A mathematical model of the chilled water plant design and operation problem is developed. The model minimizes the life cycle cost of a chilled water plant through selection of chilled water plant equipment and specification of an optimal operating schedule for the equipment. The problem is formulated as a mixed integer linear programming problem where non-linear chiller performance curves are transformed into linear constraints through the use of integer variables. The model is decomposed into design and operation problems. The design problem is solved heuristically with the underlying operational problem solved using branch and bound techniques. The solution approach is demonstrated through application to a case study. Results indicate that the approach can be used to establish a plant configuration and an operating strategy for all-electric, all-gas, and hybrid chiller plant configurations with the optimal design dependent upon the utility cost structure.
Analysis of Extended Environomic Cost Influence on Conventional Energy Systems Design
Authors: Borchiellini R. , Calì M. , Santarelli M. 
Published: November 2021

Abstract
In the paper the authors analyse how the application of an extended environomic procedure, based on charges linked to the pollutant activities of energy systems, influences the energy behaviour of energy systems.
If in the economic balance of an energy plant a cost is assigned only to the pollutant emissions (Environmental Cost), it can be shown that this choice allows a good promotion of the abatement devices and of the switching fuel approach, but the efficient utilization of energy resources is not sufficiently promoted.
The extended approach, here analysed, takes into account both the pollutant emissions and the inefficient use of energy resources. In the proposed method, on the basis of thermodynamic considerations, a cost is assigned to the exergy rate destroyed inside the system and to the exergy flows rejected into the biosphere with the plant wastes (Efficiency Penalty).
Many calculations have been developed using different sets of both the Environmental Cost and the Efficiency Penalty; assigning different weights to them. The calculations have been applied to a 30 MWel gas turbine cogeneration power plant (CGAM), and to an existing 350 MW combined cycle, considering the pollutant emissions of CO, NOx, SOx and CO2. The obtained results show that this approach can become a real energy policy instrument: in fact it allows to stimulate high efficiency design of conventional plants and advanced high-efficiency low-pollutant energy systems, becoming an opportunity to disseminate advanced technologies that still have difficulties to compete in the energy market due to their high investment costs.
Enhancing the Steam-Reforming Process With Acoustics: A Theoretical Investigation of Potential Benefits for Application in Fuel Cell Vehicles
Authors: Erickson Paul A. , Roan Vernon P. 
Published: November 2021

Abstract
This paper provides a theoretical basis for the investigation of using acoustic waves as a means of enhancing performance in conjunction with the hydrocarbon fuel steam-reforming process for application in fuel cell vehicles. In order to minimize liabilities associated with steam-reforming, a novel reforming enhancement is being investigated.
A reformation process that utilizes acoustic fields in critical fluid paths is introduced. Potential benefits of using acoustic fields in the reformation process are decreased effective space velocity, an increase of convective heat transfer rates, and increased specie mixing that would help produce an increase in capacity and overall reaction rate for a given reformer volume. The proposed acoustic enhancement should result in some combination of quicker start up times, faster dynamic response, smaller size and lower weight.
Enhancing Fuel Cell/Gas Turbine Hybrid Power Systems via

Reduced

Fuel Utilization Within Indirect Internally Reforming (IIR) Fuel Cell Stacks
Authors: Haynes Comas , Wepfer William J. 
Published: November 2021

Abstract
A system design process innovation is reported, in conjunction with a fuel cell/ gas turbine hybrid power system (HPS). Lowering cell stack fuel utilization increases system power generation and cost effectiveness. This occurs with minimal penalty to the system’s lofty efficiency. The cell stack produces more power at lower fuel utilizations, because reactant flows to the stack actually increase. The bottoming gas turbine also increases in power production, because a greater amount of unreacted fuel fires it. Since power generation installation cost is normalized per unit capacity rating (e.g., $/kW), increasing power production is a viable means of lowering capital costs. At lower cell stack fuel utilizations, enhanced regenerative effects within the HPS counteract the increasing prevalence of combustion. System efficiency thus remains stable. The adage that best system performance occurs at the highest cell stack fuel utilizations is based on “parallel plant” logic. The investigators have shown, however, that such reasoning is not necessarily applicable to these HPS designs (which incorporate indirect internal reformation). A process patent is pending.
Thermoeconomic Analysis of Power Plants With Integrated Exergy Stream
Authors: Kim Duck-Jin , Lee Hyun-Soo , Kwak Ho-Young , Hong Jae-Ho 
Published: November 2021

Abstract
Exegetic and thermoeconomic analysis were performed for a 500-MW combined cycle plant and a 137-MW steam power plant without decomposition of exergy into thermal and mechanical exergy. A unit cost was assigned to a specific exergy stream of matter, regardless of its condition or state in this analysis. The calculated costs of electricity were almost same within 0.5% as those obtained by the thermoeconomic analysis with decomposition of the exergy stream for the combined cycle plant, which produces the same kind of product. Such outcome indicated that the level at which the cost balances are formulated does not affect the result of thermoeconomic analysis, that is somewhat contradictory to that concluded previously. However this is true for the gas-turbine cogeneration plant which produces different kinds of products, electricity and steam whose unit costs are dominantly affected by the mechanical and thermal exergy respectively.
The Combined First and Second Laws of Thermodynamics and Exergy Analysis
Authors: Adebiyi George A. 
Published: November 2021

Abstract
A novel approach is proposed for combining the first and second laws of thermodynamics for systems undergoing arbitrary, non-reversible processes. A reference environment at an intensive state (p0, T0) is assumed, and combination of the two laws of thermodynamics yields the familiar equations used in the exergy analysis of processes.
The application of the laws of thermodynamics was made first to non-flow processes involving closed systems. An extension to the control volume and flow processes was carried out via the use of the Reynolds transport theorem.
Theoretical and Experimental Evaluation of the EvGT-Process
Authors: Lindquist Torbjörn O. , Rosén Per M. , Torisson Tord 
Published: November 2021

Abstract
In recent years the interest for new advanced thermodynamical gas turbine cycles has increased. One of the new designs is the evaporative gas turbine cycle. A lot of effort worldwide has been put into predicting the possible efficiency, pollutants, and dynamic behaviour of the evaporative gas turbine cycle, but all results so far have been affected by uncertain assumptions. Until now this cycle has not been demonstrated in a pilot plant. The purpose of this work has been to identify the potential of this cycle, by erecting a pilot plant at the Lund Institute of Technology. The project was financed on a 50/50 basis from the Swedish National Energy Administration and the industrial partners.
Three different thermodynamical cycles have been tested in the pilot plant: the simple, the recuperative, and the evaporative cycles. The final pilot plant roughly consists of a 600 kW gas turbine, a hydraulic brake, a recuperator, a humidification tower, an economiser, and a flue gas condenser. All layout and functional analysis were made within the project. The pilot plant is, however, optimized neither for best efficiency nor for best emissions. It has only been built for demonstration purpose.
It has been shown from the performance tests that the efficiency for the simple, recuperative, and evaporative cycles are 22, 27, and 35%, respectively, at rated power output. The NOx emissions were reduced by 90% to under 10 ppm, and the UHC and CO were not measurable when running the evaporative cycle at rated power output. The performance of the humidification tower was better than expected. The humidified air out from the humidification tower is always saturated. The pinch point, i.e. the temperature difference between the outcoming water from the humidification tower and the saturation temperature of the incoming air, is around 3°C. The water circuit was closed, i.e. there was no need for additional water, when the flue gases after the flue gas condenser reached a temperature of 35° C.
The inhouse heat balance program, used for both cycle optimization and evaluation, has been verified. The evaporative gas turbine cycle has, when optimized, at least the same efficiency as the best combined cycle today, based on the same gas turbine. The evaporative cycle will also show very good performance when used in small scale power plants.
An Integrated Approach for Gas Turbine Engine Simulation
Authors: Xie Zhiwu , Su Ming , Weng Shilie 
Published: November 2021

Abstract
The static and transient performance of a gas turbine engine is determined by both the characteristics of the engine components and their interactions. This paper presents a generalized simulation framework that enables the integration of different component and system simulation codes.
The concept of engine simulation integration and its implementation model is described. The model is designed as an object-oriented system, in which various simulation tasks are assigned to individual software components that interact with each other. A new design rationale called “message-based modeling” and its resulting class structure is presented and analyzed.
The object model is implemented within a heterogeneous network environment. To demonstrate its flexibility, the codes that deal with different engine components are separately programmed on different computers running various operating systems. These components communicate with each other via a CORBA compliant ORB, which simulates the overall performance of an engine system.
The resulting system has been tested on a Local Area Network (LAN) to simulate the transient response of a three-shaft gas turbine engine, subject to small fuel step perturbations. The simulation results for various network configurations are presented. It is evident that in contrast to a standalone computer simulation, the distributed implementation requires much longer simulation time. This difference of simulation efficiency is analyzed and explained.
The limitations of this endeavor, along with some future research topics, are also reported in this paper.
Optimization of the Thermodynamic Efficiency of a Recuperative Heat Exchanger
Authors: Adebiyi George A. 
Published: November 2021

Abstract
A heat exchanger is strictly speaking a thermal exergy transfer device, and the proper measure of its efficiency is the second law efficiency. This article considers the efficiency of a single-pass, recuperative heat exchanger in which a given stream of hot fluid is available for heating a cold stream of fluid in a specified manner. The analysis takes cognizance of the required exergy input to overcome fluid friction in the flow passages, as well as the thermal exergy flow rates for the fluid streams, in the determination of the second-law efficiency. Maximization of the second-law efficiency is found to provide a basis for sizing the heat exchanger for optimum thermodynamic efficiency of operation.
The key parameters that determine this optimum include the number of transfer units (NTU), the ratio of thermal capacity rates (Cr), a dissipation parameter which involves the Eckert and Prandtl numbers, and the flow configuration (whether parallel-flow, or counter-flow). Other parameters relevant to the performance of the heat exchanger are the tare capacity (εtare), and the ratio of the inlet temperature of the hot fluid to the ambient temperature.
Evaluation and Optimization of Automated Operation in Small CHP Plants
Authors: Grue Jeppe , Andersen Jens , From Niels , Bach Inger 
Published: November 2021

Abstract
In Denmark power generation is extensively based on small combined heat and power plants, which produce electric power and district heating. This work will focus on the small plants around 1 MW in size, which are often unmanned and operating completely automatically. The objective of this work is to formulate a method which can be used to determine the optimal operating strategy for a CHP plant, and that this strategy must be fully automated. The contribution margin of the plant is used as the objective function for the optimization. Finally the method is tested on a small CHP plant, which is a gas engine producing 1.34 MW electrical power and 1.6 MJ/s district heating. The methods, which are developed, can be used in general for the evaluation and optimization of automated strategies for the operation of small-unmanned CHP plants. The strong feature of the method is that it sets an ultimate target that is the best possible one to obtain with a view to any strategy. This provides a basis for the evaluation and optimization of the actual strategy.
Determining Optimal Operating Conditions for Cogeneration Systems Using Minimum Entropy Generation Rate and Maximum Performance Criterion
Authors: Kowalski Gregory J. , Zenouzi Mansour 
Published: November 2021

Abstract
Many systems, such as domestic residences and business, institutional or shopping building complexes, require both a power input and a heat input to properly operate. Usually, the power input is in the form of electricity. An analysis for determining the most advantageous method of satisfying the energy requirements for these types of systems and of estimating the maximum possible value of the energy utilization factor is developed using an idealized regeneration cycle with heat exchangers that operate between different temperature reservoirs. The results are summarized in terms of the ratio of the heat load to the required power, (HLRP). The HLRP ratio is the significant design factor for these system and all results are scalable with it. The first law thermal efficiency or energy utilization factor and the entropy generation rate, (EGR), are determined at different practical operating conditions. The EGR is directly proportional to the rate of exergy destruction because of the system definition used in the analysis. The usefulness of the thermal efficiency and the EGR as design tools is investigated. The first law thermal efficiency reaches a maximum possible value of 76% at a HLRP ratio value of 0.67 for practical values of the operating conditions. At this HLRP ratio value the heat rejected from the heat engine equals the required heat load, the critical HLRP value. No minimum behavior was observed for the EGR as a function of the HLRP ratio for the cogeneration system. The EGR results are not a useful design tool during the initial design phase for cogeneration systems because of this trend. The results suggest that cogeneration systems should be selected for HLRP ratio values that are greater than the critical value. As the HLRP ratio increases the performance of the cogeneration system approaches that of the traditional system and are in an operating range that is governed by cost factors rather than energy usage factors. The results are compared to irreversible heat engine system and to a system without cogeneration. This research is the only first step of an investigation that will include the cost analysis and comparison to operating cogeneration installations in the next phase.
A New Type of Gas Turbine Based-Hybrid Propulsion System: Part 1—Concept Development, Definition of Mission Parameters and Preliminary Sizing
Authors: Cioffarelli Emiliano , Sciubba Enrico 
Published: November 2021

Abstract
A hybrid propulsion system of new conception for medium-size passenger cars is described and its preliminary design developed. The system consists of a turbogas set operating at fixed rpm, and a battery-operated electric motor that constitutes the actual “propulsor”. The battery pack is charged by the thermal engine which works in an electronically controlled on/off mode. Though the idea is not entirely new (there are some concept cars with similar characteristics), the present study has important new aspects, in that it bases the sizing of the thermal engine on the foreseen “worst case” vehicle mission (derived from available data on mileage and consumption derived from road tests and standard EEC driving mission cycles) that they can in fact be accomplished, and then proceeds to develop a control strategy that enables the vehicle to perform at its near–peak efficiency over a wide range of possible missions. To increase the driveability of the car, a variable-inlet vane system is provided for the gas turbine.
After developing the mission concept, and showing via a thorough set of energy balances (integrated over various mission profiles), a preliminary sizing of the turbogas set is performed. The results of this first part of the development program show that the concept is indeed feasible, and that it has important advantages over both more traditional (Hybrid Vehicles powered by an Internal Combustion Engine) and novel (All-Electric Vehicle) propulsion systems.
Impact of Reformer/Burner Thermal Integration on the Efficiency and Dynamic Response of an Onboard Fuel Processor in an Indirect Methanol Fuel Cell Vehicle
Authors: Ramaswamy Sitaram , Sundaresan Meena , Moore Robert M. 
Published: November 2021

Abstract
Using a fuel other than pure hydrogen in a fuel cell vehicle (FCV) employing a proton exchange membrane (PEM) fuel cell stack typically requires an on-board fuel processor to provide hydrogen-rich fuel to the stack. On board fuel processors that generate hydrogen from on-board liquid methanol (and other Hydrocarbons) have been proposed as possible alternative sources of hydrogen needed by the fuel cell. This paper focuses on a methanol fueled fuel processor that using steam reformation process to generate hydrogen. The reformation process involves a steam reformer and a catalytic burner (which provides the necessary energy for the endothermic steam reforming reactions to occur). This paper focuses on the importance of reformer/burner thermal integration and its impact on the dynamic response of the fuel processor. The model uses MATLAB/Simulink software and the simulation provides results for both dynamic response and energy efficiency.
Experimental Investigation of Convective Melting of Granular Packed Bed Under Microgravity
Authors: Jiang J. , Hao Y. , Tao Y.-X. 
Published: November 2021

Abstract
To improve the understanding of convective melting of packed solid particles in a fluid, an experimental investigation is conducted to study the melting characteristics of a packed bed by unmasking the buoyancy forces due to the density difference between the melt and solid particles. A close-loop apparatus, named the particle-melting-in-flow (PMF) module, is designed to allow a steady state liquid flow under a specified temperature. The module is on board NASA’s KC-135 reduced gravity aircraft for the experiments. In the test module, water is used as the fluid, and ice particles are fed to the test section at the beginning of the test. As the liquid flows though the bed, the solid grains melt. A perforate plate, through which liquid can flow while the ice particles are retained, bounds the downstream of the packed bed. From the digital video images the local packed bed thickness is measured under control flow rate, and the melting rate is determined. The temperature distribution along the horizontal direction and vertical direction is measured using 19 thermocouples. An infrared camera is mounted to record the local temperature variation between liquid and solid. The melting rates are presented as a function of upstream flow velocity, temperature and initial average particle size of the packed bed. It is found that the melting rate is influenced mainly by the ratio of the Reynolds number (Re, based on the initial particle diameter) to the square of the Froud number (Fr), and me Stefan number (Ste). In general, the dimensionless melting rate decreases as Re/Fr2 increases and increases as Ste increases. With the absence of gravity, i.e., Froud number approaches infinity, a maximum melting rate can be achieved for otherwise the same test conditions. The increase in the melting rate with the increase in Stephan number also becomes more pronounced under the zero gravity condition.
Development of an Analytical Model: Tank Pressure Control Experiment
Authors: Albayyari Jihad M. , Subramanya Karteek K. 
Published: November 2021

Abstract
The “Reduced-Fill Tank Pressure Control Experiment (TPCE/RF)” is a space experiment developed to meet the need for a critical aspect of cryogenic fluid management technology: “control of storage tank pressures in the absence of gravity by forced-convection mixing”. The experiment used Freon-113, at near saturation conditions and a constant 40% fill level, to simulate the fluid dynamics and thermodynamics of cryogenic fluids in space applications. The objectives of TPCE/RF were: Characterize the fluid dynamics of an axial jet-induced mixing in low gravity. Evaluate the validity of empirical mixing models, and provide data for use in developing and validating computational fluid dynamics model of mixing processes.
TPCE/RF accomplished all of its objectives in flight on the Space Shuttle flight in May 1996. The flow patterns observed generally agreed with a prior correlation derived from drop tower tests. Several existing mixing correlations were found to provide reasonable performance predictions. Low-energy mixing jets, dissipating on the order of 1% of the kinetic energy of previous mixer designs, were found to be effective and reliable at reducing thermal non-uniformities, promoting heat and mass active mixing, whether continuous or periodic, offers increased reliability and predictability in space cryogenic systems and can be accomplished with no significant boiloff penalty caused by kinetic energy dissipation.
MEMS as In-Vivo Sensors and Actuators: Challenges and Opportunities
Authors: Mahajan Roop L. 
Published: November 2021

Abstract
MicroElectroMechanical Systems (MEMS) is a developing field which promises to open up new fields of applications in such diverse areas as medical systems, wireless communications and space explorations. They are particularly attractive to the medical community for their consistent reproducibility, high levels of accuracy and reliability, and exceptional stability. This is achieved through silicon micro-fabrication techniques conducive to high volume manufacturing at a low cost.