Power Generation with Renewable Energy and Advanced Supercritical CO2 Thermodynamic Power Cycles: A Review

Supercritical CO2 (S-CO2) thermodynamic power cycles have been considerably investigated in the applications of fossil fuel and nuclear power generation systems, considering their superior characteristics such as compactness, sustainability, cost-effectiveness, environmentally friendly working fluid, and high thermal efficiency. They can be potentially integrated and applied with various renewable energy systems for low-carbon power generation such that extensive studies in these areas have also been conducted substantially. However, there is a shortage of reviews that specifically concentrate on the integrations of S-CO2 with renewable energy encompassing biomass, solar, geothermal, and waste heat. It is thus necessary to provide an update and overview of the development of S-CO2 renewable energy systems and identify technology and integration opportunities for different types of renewable resources. Correspondingly, this paper not only summarizes the advantages of CO2 working fluid, design layouts of S-CO2 cycles, and classifications of renewable energies to be integrated but also reviews the recent research activities and studies carried out worldwide on advanced S-CO2 power cycles with renewable energy. Moreover, the performance and development of various systems are well grouped and discussed

ECOS 2012

The 8-volume set contains the Proceedings of the 25th ECOS 2012 International Conference, Perugia, Italy, June 26th to June 29th, 2012. ECOS is an acronym for Efficiency, Cost, Optimization and Simulation (of energy conversion systems and processes), summarizing the topics covered in ECOS: Thermodynamics, Heat and Mass Transfer, Exergy and Second Law Analysis, Process Integration and Heat Exchanger Networks, Fluid Dynamics and Power Plant Components, Fuel Cells, Simulation of Energy Conversion Systems, Renewable Energies, Thermo-Economic Analysis and Optimisation, Combustion, Chemical Reactors, Carbon Capture and Sequestration, Building/Urban/Complex Energy Systems, Water Desalination and Use of Water Resources, Energy Systems- Environmental and Sustainability Issues, System Operation/ Control/Diagnosis and Prognosis, Industrial Ecology

Techno-economic projections for advanced small solar thermal electric power plants to years 1990-2000

Advanced technologies applicable to solar thermal electric power systems in the 1990-200 time-frame are delineated for power applications that fulfill a wide spectrum of small power needs with primary emphasis on power ratings less than 10MWe. Projections of power system characteristics (energy and capital costs as a function of capacity factor) are made based on development of identified promising technologies and are used as the basis for comparing technology development options and combinations of these options to determine developmental directions offering potential for significant improvements. Stirling engines, Brayton/Rankine combined cycles and storage/transport concepts encompassing liquid metals, and reversible-reaction chemical systems are considered for two-axis tracking systems such as the central receiver or power tower concept and distributed parabolic dish receivers which can provide efficient low-cost solar energy collection while achieving high temperatures for efficient energy conversion. Pursuit of advanced technology across a broad front can result in post-1985 solar thermal systems having the potential of approaching the goal of competitiveness with conventional power systems

Evaluation of Process and Economic Feasibility of Implementing a Topping Cycle Cogeneration System

Industrial applications that require steam for their end-uses generally utilize steam boilers that are at higher size than what is typically required. Similarly, gas turbine-based power plants corroborate the gas turbine system and eventually relieve the exhaust into the atmosphere. These facilities include food, paper, chemicals, refining, and primary metal manufacturing industries. This research focuses on the scope of a topping cycle combined heat and power (CHP) system by pushing the load on the boiler to a higher limit, or a gas turbine operation in place of a boiler system for a topping cycle CHP and its economic feasibility by utilizing the turbine exhaust to achieve the technological and economical evaluation of a CHP system. The excess steam is run through a condensing steam turbine to generate power that can offset the facility’s electricity usage cost and under favorable conditions, sell electricity back to the grid. Similarly, the steam turbine outlet water can be used to satisfy the plant’s heating needs in the form of comfort and district heating. A decision tool was developed to evaluate the technical and economic feasibility of a topping cycle CHP system, which can emulate a given facility’s steam or gas system and its operational parameters with steam turbines. It will help the user realize the point of breakeven (in terms of fuel cost incurred and overall cost savings) at the desired steam flow rate for a corresponding boiler system. Similarly, sensitive analysis of energy, power, cost savings, and payback of investment to boiler and steam parameters is also carried out. The research would provide necessary insights into the most appropriate parameters that will enable a CHP system to be advantageous in technical and economic aspects. The research determines that the fuel cost, electricity cost, and the steam quantity flowing through the turbines are the most important parameters for a desirable payback on the investment

Energy Conversion Alternatives Study (ECAS)

ECAS compared various advanced energy conversion systems that can use coal or coal-derived fuels for baseload electric power generation. It was conducted in two phases. Phase 1 consisted of parametric studies. From these results, 11 concepts were selected for further study in Phase 2. For each of the Phase 2 systems and a common set of ground rules, performance, cost, environmental intrusion, and natural resource requirements were estimated. In addition, the contractors defined the state of the associated technology, identified the advances required, prepared preliminary research and development plans, and assessed other factors that would affect the implementation of each type of powerplant. The systems studied in Phase 2 include steam systems with atmospheric- and pressurized-fluidized-bed boilers; combined cycle gas turbine/steam systems with integrated gasifiers or fired by a semiclean, coal derived fuel; a potassium/steam system with a pressurized-fluidized-bed boiler; a closed-cycle gas turbine/organic system with a high-temperature, atmospheric-fluidized-bed furnace; a direct-coal-fired, open- cycle magnetohydrodynamic/steam system; and a molten-carbonate fuel cell/steam system with an integrated gasifier. The sensitivity of the results to changes in the ground rules and the impact of uncertainties in capital cost estimates were also examined

Innovative waste heat valorisation technologies for zero-carbon ships − A review

The growing intensity of international commerce and the high share of total global greenhouse gas emissions by the maritime sector have motivated the implementation of regulations by the International Maritime Organisation to curtail vessel emissions. In this context, waste heat recovery (WHR) is an effective way to improve ship energy efficiency, lower amounts of wasted energy rejection to the environment, and therefore ultimately curb green-house gas emissions. Presently, there exists a heterogeneity within the body of literature concerning WHR technologies for on-board applications, study scope and results, complicating the interpretation and cross comparison of the outcomes. Sporadic attempts have been made to review and systematise this landscape, leaving some key areas uncovered. Therefore, the present article aims at filling these gaps by providing and holistic review of WHR technologies development and on-board applications. Further, the energy systems and available waste heat characteristics in large vessel types are overviewed, before both existing and developmental on-board waste heat recovery technologies for maritime applications are reviewed. Emphasis is placed on the performance of these technologies within the broader on-board energy system. Common key performance indicators are drawn from existing systems, experimental prototypes, and simulations, to quantitatively compare the different technologies. This review indicates that a wide range of technological options for embedding waste heat recovery in on-board energy systems are emerging. In particular, traditional turbocompounding is already fully implemented within the marine waste heat recovery (WHR) context. Conversely, ORC systems and absorption refrigeration systems have not yet been suitably adapted for marine applications due to a lack of research and prototypes, despite their deployment in conventional WHR contexts. Other technologies, such as thermal energy storage devices, hybrid refrigeration systems, isobaric expansion engines, Kalina Cycles, and adsorption desalination and cooling systems, are still at the research and development stage, while thermo-electric generation systems continue to incur high deployment costs. The development of research on these innovative technologies, the reduction of their cost and their synergistic integration could lead to significant improvements inengine fuel efficiency and emissions reduction, especially when coupled with existing waste heat recovery measures

Thermodynamic Analysis For Improving Understanding And Performance Of Hybrid Power Cycles Using Multiple Heat Sources Of Different Temperatures

Past studies on hybrid power cycles using multiple heat sources of different temperatures focused mainly on case studies and almost no general theory about this type of systems has been developed. This dissertation is a study of their general thermodynamic performance, with comparisons to their corresponding single heat source reference systems. The method used in the dissertation was step-wise: to first analyze the major hybrid power cycles (e.g. Rankine, Brayton, Combined Cycles, and their main variants) thermodynamically, without involving specific operation parameter values, and develop some generalized theory that is at least applicable to each type of system. The second step was to look for commonalities among these theories and develop the sought generalized theory based on these commonalities. A number of simulation case studies were performed to help the understanding and confirm the thermodynamic results. Exergo-economic analysis was also performed to complement the thermodynamic analysis with consideration of externalities, and was compared to the conventional economic analysis method. The generalized expressions for the energy/exergy efficiency differences between the hybrid and the corresponding single heat source systems were developed. The results showed that the energy and exergy efficiencies of the hybrid systems are higher than those of their corresponding single heat source reference systems if and only if the energy/exergy conversion efficiency (defined in the dissertation) of the additional heat source (AHS, can be any heat source that has lower temperature) is larger than that of the original heat source. Sensitivity analysis results showed the relations between the temperature and heat addition rate of the AHS and the energy/exergy efficiency of the hybrid systems. Other big advantages of hybrid systems, i.e. the effects on replacement of fossil fuel by renewable, nuclear and waste energy, lower emissions and depletion of fossil fuel, were revealed in the economic analysis, by considering the cost reduction from fuel saving and carbon tax. Simple criteria were developed to help compare the hybrid and reference systems and determine under which conditions the hybrid systems will have better thermodynamic or economic performance than the reference ones. The results and criteria can be used to help design the hybrid systems to achieve higher energy and/or exergy efficiencies and/or lower levelized electricity cost (LEC) before detailed design or simulation or experiment. So far, 3 archival journal papers and 3 conference papers were published from this dissertation work

Energy: A continuing bibliography with indexes, issue 38

This bibliography lists 1367 reports, articles and other documents introduced into the NASA scientific and technical information system from April 1, 1983 through June 30, 1983

Linking a Fluidized Bed Combustion Reactor with an Externally Fired Micro Gas Turbine

The purpose of this research work is to develop and test a small-scale system based on a stationary fluidized bed combustion reactor linked with an externally fired micro gas turbine. A heat exchanger transfers the heat of combustion to the compressed air stream entering the turbine. This cycle allows the combustion of solid biomass in a gas turbine without the problems associated with erosion, slagging, fouling, and corrosion of the turbine blades. By linking a stationary fluidized bed with an externally fired micro gas turbine an efficient small scale distributed electricity generation system for readily available problematic biomass fuels such as agricultural and forestry residues has been developed.Gegenstand der Arbeit sind die Entwicklung und Erprobung eines innovativen Konzepts zur Stromerzeugung aus Biomasse in einer extern gefeuerten Mikrogasturbine gekoppelt mit einer stationären Wirbelschichtfeuerung. Mit dieser Technik können Problembrennstoffe wie halmgutartige Biomasse direkt im Prozess verbrannt werden. Die Wärme wird über einen Wärmeübertrager auf die Turbine geleitet, ohne dass dabei für die Turbine die bekannten Probleme des Teeranfalls, der Verschmutzung und Korrosion auftreten. Damit ist es gelungen, eine kleine effiziente Anlage zu entwickeln, die eine dezentrale Stromerzeugung im kleinen Leistungsbereich aus festen Problembrennstoffen ermöglicht