MDAC/Rocketdyne solar receiver: design review

Concentrated solar power (CSP) is a cutting-edge method of conserving renewable energy. The concentrated solar power is utilized as a heating source to increase the temperature of heat transfer fluid circulating in the piping of the central solar receiver. The solar central receiver is the most crucial part in solar tower power plants. In this study, a Computational Fluid Dynamics (CFD) framework was developed for analyzing four designs of the central tower receiver, namely, a conventional uniform tube diameter solar receiver (UTD), vertical variable tube diameter solar receiver (VTD), a circular solar variable tube diameter (CVTD) receiver and a leaf type circular solar receiver (LTSR). This analysis studied the solar radiation heat transfer efficiency, temperature distribution, and fluid outlet temperature; pressure and velocity distributions for the designs using CFD. It was found that the CVTD design helped achieve a higher rise in temperature of the heat transfer fluid (HTF) when the mass flow rate was in the range of 0.1 to 0.2 liter per minute. The CVTD and LSTR models of receiver were more efficient heat transfer receiver designs compared with other designs for same surface area and strength of beam radiations.

Next-generation high-flux concentrated solar receivers are deemed to operate at temperatures exceeding 1000ºC to enable advanced power cycles with high thermal-to-electric conversion efficiencies. The high temperature of a solar receiver, however, increases radiation losses (∝ T4), thereby degrading the solar-to-thermal conversion efficiency. Additionally, state-of-the-art 3D-printed metal and supper-alloy-based solar receivers fail to properly operate at high receiver temperatures due to excessive oxidation and creep experienced. To overcome the trade-off between the solar-to-thermal and thermal-to-electric conversion efficiency at high temperatures, and meet material requirements, transformational innovations in both the design and material of solar receivers should be made. This research proposes 3D-printed hierarchically-ordered and nature-inspired ceramic volumetric receivers for high-flux high-temperature solar thermal collectors. Particularly, a new class of high-flux volumetric solar receivers inspired by the stone lotus plant is introduced and examined. The conceptualized lotus-inspired solar receiver offers a low optical thickness and excellent light-trapping effects combined with strong convective effects. As a result, the lotus-inspired receiver remarkably improves both optical and thermal characteristics, thereby augmenting the solar-to-thermal conversion efficiency at high temperatures. These characteristics enable substantially increasing the outlet temperature of the receiver working fluid (i.e., air), thereby maximizing the so-called “volumetric effect” (i.e., a higher outlet fluid temperature than the receiver’s aperture temperature). To withstand high temperatures of future high-flux solar receivers and realize intricate topologies of the lotus-inspired class of solar receivers, here, 3D-printed ceramic volumetric receivers are adapted for high-flux solar receivers. Ceramics demonstrate some highly desirable thermal, mechanical, and corrosion resistance properties, including strength at temperatures exceeding 1000°C. However, ceramics are brittle and hard to be machined or shaped to a desired solar receiver architecture. Therefore, the proposed work matures ceramic 3D printing for advanced high-flux solar collectors. To better understand and thus design such advanced high-flux solar receivers, a detailed understanding of key parameters affecting opto-thermal performance of high-flux receivers is necessary. Therefore, a 3D pore-level Monte Carlo ray-tracing model was developed to examine the conjugate radiative, convective, and conductive heat transfer mechanisms of 3D-printed ceramic solar collectors. The model was first employed for lattice receivers with uniform and non-uniform porous structures. This allowed to systematically understand coupled optical and thermal characteristics of solar receivers at the pore level. It was found that the solar-to-thermal conversion efficiency might be thermally or optically limited depending on the thermo-hydraulic characteristics of the working fluid. The understanding obtained from the pore-level Monte Carlo ray-tracing modeling paved the

The primary goal of this research is to create a new billboard-style central spherical solar receiver with varying header and tube diameter, for which two spiral central receiver designs and a new circular central solar receiver with varying pipe radius and varying mass circulation are utilized. The exhaust temperature of the water was determined employing a computational fluid dynamics assessment employing ANSYS Fluent. Following the verification of the standards models, a novel central solar receiver project was made that accomplishes computational fluid dynamics assessment with almost the same boundary condition.The heat export fluid is water, and the spiral coil tube is copper. The mass circulation rate varies among 0.1 LPM, 0.2 LPM, and 0.3 LPM, with the inlet temperature of water being 299K at continuous solar irradiation. The findings demonstrate that at 0.1 LPM, the redesign of the central solar receiver produces a temperature of 383.9 K, which is 28.39 percent higher than the inlet temperature and 7.32 percent higher than the spiral central receiver. As a consequence, the circular central solar recipient to varying pipe radius is suggested and considered in upcoming usages

ABSTRACTIn this paper, optimisation of the supercritical CO Brayton cycles integrated with a solar receiver, which provides heat input to the cycle, was performed. Four S-CO Brayton cycle configurations were analysed and optimum operating conditions were obtained by using a multi-objective thermodynamic optimisation. Four different sets, each including two objective parameters, were considered individually. The individual multi-objective optimisation was performed by using Non-dominated Sorting Genetic Algorithm. The effect of reheating, solar receiver pressure drop and cycle parameters on the overall exergy and cycle thermal efficiency was analysed. The results showed that, for all configurations, the overall exergy efficiency of the solarised systems achieved at maximum value between 700°C and 750°C and the optimum value is adversely affected by the solar receiver pressure drop. In addition, the optimum cycle high pressure was in the range of 24.2–25.9 MPa, depending on the configurations and reheat condition.

Experimental demonstration of the hybrid solar receiver combustor

A Mid-Term Review of the Barstow pilot plant was held in Barstow, California, in July 1983. At that meeting, a panel of representatives from various utilities and repowering studies gathered to review the first year of the Test and Evaluation Phase, as well as the planned activities for the second year of that phase. The panel concurred that plant checkout and testing have progressed well, and they fully support next year's test plan. In general, the panel's recommendations fall into four categories: (1) Information dissemination - information about the success of the pilot plant needs to reach key decision makers; (2) Automation - work on the automatic control system needs to be completed; (3) Electricity production - in this next year, the plant should operate as an energy producer as much as possible; and (4) Energy balances - increased effort should be directed at performing energy balances. These and other recommendations are more fully described in the body of this report. This document also presents summaries of the presentations made at the meeting and a list of the reports that will be prepared during the last half of the Test and Evaluation Phase. The list of meeting participants and the agenda can be found in Appendixes A and B, respectively.

Development of a petrochemical process from laboratory scale tests to a commercial plant. A plant producing TAME (tertiary amyl methyl ether) and isoamylene serves as an example illustrating the development of a petrochemical process from laboratory scale tests to a commercial size plant. TAME is an anti‐knock compound used in unleaded gasoline, and isoamylene is a multi‐purpose specialty chemical. In an introduction, the laboratory and pilot plants at EC Erdoelchemie GmbH in Cologne, Germany are presented. Subsequently the main process engineering developments made through experience gained with a semicommercial demonstration plant are discussed. These include optimization of the reactors, design of a methanol extraction unit, and the separation of TAME and high purity isoamylene in specially designed distillation towers. The high degree of coordination during the experimental testing phase to match the requirements of the basic and detail engineering allowed the commercial plant to be started up without expensive modifications within 4 years. The resulting savings overcompensate the costs of the semicommercial plant.

This report assesses the performance of the H-Coal process, a catalytic direct liquefaction process, at a process development and large pilot-plant scale of operation. The assessment focused on the evaluation of operating results from selected long-term successful process development unit (PDU) and pilot plant runs made on Illinois No. 6 coal. The pilot plant has largely duplicated the product yield structure obtained during the PDU runs. Also, the quality of products, particularly liquid products, produced during the pilot plant run is quite comparable to that produced during the PDU runs. This confirms the scalability of the H-Coal ebullated-bed reactor system from a PDU-scale, 3 tons of coal per day, to a large pilot scale, 220 tons of coal per day, plant. The minor product yield differences, such as higher yields of C/sub 3/, C/sub 4/, and naphtha fractions, and lower yields of distillate oils obtained during pilot plant runs as compared to the PDU runs, will not impact the projected technical and economic performance of a first-of-a-kind commercial H-Coal plant. Thus, the process yield and operating data collected during the PDU operations provided an adequate basis for projecting the technical and economic performance of the proposed H-Coal commercial plant. 18 references, 9 figures, 56 tables.

Spreadsheets have been used to collect and understand existing solar thermal central receiver design data. Correlation of these data has led to the development of many useful algorithms. The algorithms provide the basis for calculating performance efficiencies, annual energy production, plant cost, and levelized energy cost. Variations in design details are evaluated with example results of the effect of plant location, collector field dield size, efficiencies for North and surround configurations as a function of field size, efficiencies of external and cavity receivers for similar operating conditions, and interactions of the collector field and receiver design. Examples are also presented for the plant total capital investment and levelized energy cost as a function of the annual energy produced. Sensitivities to various parameters affecting the net annual energy production and levelized energy cost are also discussed. The performance and cost characteristics of large and small plants are considered. Use of the spreadsheet analysis is demonstrated where one possible design utilizes modular solar systems. The design includes a single steam generator and turbine plant. This optimizes the performance and cost attributes of both small solar and large non-solar systems to arrive at a more cost-effective plant.

04/02893 GaAs/Ge solar cell AC parameters underillumination: Anil Kumar, R. et al. Solar Energy, 2004, 76, (4), 417–421

Volumetric receivers in Solar Thermal Power Plants with Central Receiver System technology: A review

Unique Challenges in the Design and Operation Philosophy of Solar Thermal Power Plants

This is the Executive Summary of a study conducted for Phase 1 of a two-phase project whose objectives were to develop a reliable, cost-effective molten salt steam generating subsystem for solar thermal plants, minimize uncertainty in capital, operating, and maintenance costs, and demonstrate the ability of molten salt to generate high-pressure, high-temperature steam. The Phase 1 study involved the conceptual design of molten salt steam generating subsystems for a nominal 100-MWe net stand-alone solar central receiver electric generating plant, and a nominal 100-MWe net hybrid fossil-fueled electric power generating plant that is 50% repowered by a solar central receiver system. As part of Phase 1, a proposal was prepared for Phase 2, which involves the design, construction, testing and evaluation of a Subsystem Research Experiment of sufficient size to ensure successful operation of the full-size subsystem designed in Phase 1. Evaluation of several concepts resulted in the selection of a four-component (preheater, evaporator, superheater, reheater), natural circulation, vertically oriented, shell and tube (straight) heat exchanger arrangement. Thermal hydraulic analysis of the system included full and part load performance, circulation requirements, stability, and critical heat flux analysis. Flow-induced tube vibration, tube buckling, fatigue evaluation of tubesheet junctions, steady-state tubesheet analysis, and a simplified transient analysis were included in the structural analysis of the system. Operating modes and system dynamic response to load changes were identified. Auxiliary equipment, fabrication, erection, and maintenance requirements were also defined. Installed capital costs and a project schedule were prepared for each design. The complete Phase 1 final report has been published as SAND 82-8179.

Floating-fixed-bed-gasification: From Vision to Reality

Thermal design of solar receivers is commonly accomplished via approximate models, where the receiver is treated as an isothermal box with lumped quantities of heat losses to the surroundings by radiation, conduction and convection. These approximate models, though adequate for preliminary design purposes, are not detailed enough to distinguish between different receiver designs, or to predict transient performance under variable solar flux, ambient temperatures, etc. A computer code has been written for this purpose and is given the name HEAP, an acronym for Heat Energy Analysis Program. HEAP has a basic structure that fits a general heat transfer problem, but with specific features that are custom-made for solar receivers. The code is written in MBASIC computer language. This document explains the detailed methodology followed in solving the heat transfer problem, and includes a program flow chart, an explanation of input and output tables, and an example of the simulation of a cavity-type solar receiver.